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Title:
WELCH BOUND SIGNATURE SEQUENCE DESIGN FOR NOMA
Document Type and Number:
WIPO Patent Application WO/2019/158691
Kind Code:
A1
Abstract:
According to one embodiment, a method implemented by a transmitter of non-orthogonal data transmission is provided. The method comprises obtaining a non-orthogonal signature sequence selected from a set of non-orthogonal signature sequences used by two or more users transmitting simultaneously on shared resources, wherein a total squared correlation for the set of signature sequences is directly proportional to the multiple access interference between users, spreading a data signal using the obtained non-orthogonal signature sequence and transmitting the spread data signal on the shared resources.

Inventors:
REIAL, Andres (Barometergatan 44, MALMÖ, SE-211 17, SE)
BEHRAVAN, Ali (Robert Almströmsgatan 3, STOCKHOLM, SE-113 36, SE)
CHITTI, Krishna (Kvarnkroken 29, LUND, SE-226 47, SE)
HARRISON, Robert Mark (3208 Walker Place, GRAPEVINE, TX, 76051, US)
Application Number:
EP2019/053809
Publication Date:
August 22, 2019
Filing Date:
February 15, 2019
Export Citation:
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Assignee:
TELEFONAKTIEBOLAGET LM ERICSSON (PUBL) (S Stockholm, SE-164 83, SE)
International Classes:
H04J13/00
Other References:
NTT DOCOMO ET AL: "NOMA scheme with user grouping", vol. RAN WG1, no. Vancouver, Canada; 20180122 - 20180126, 12 January 2018 (2018-01-12), XP051384410, Retrieved from the Internet [retrieved on 20180112]
JARKKO PAAVOLA ET AL: "Distance-Optimal Oversaturated CDMA Signature Ensemble", WIRELESS COMMUNICATION SYSTEMS, 2007. ISWCS 2007. 4TH INTERNATIONAL SYMPOSIUM ON, IEEE, PISCATAWAY, NJ, USA, 1 October 2007 (2007-10-01), pages 480 - 484, XP031166815, ISBN: 978-1-4244-0978-5
None
Attorney, Agent or Firm:
ERICSSON (Patent Development, Torshamnsgatan 21-23, STOCKHOLM, 164 80, SE)
Download PDF:
Claims:
CLAIMS

1. A method implemented by a transmitter of non-orthogonal data transmission, said method comprising:

obtaining (310) a non-orthogonal signature sequence selected from a set of non- orthogonal signature sequences used by two or more users transmitting simultaneously on shared resources, wherein a total squared correlation for the set of signature sequences is directly proportional to the multiple access interference between users;

spreading (320) a data signal using the obtained non-orthogonal signature sequence; and

transmitting (330) the spread data signal on the shared resources.

2. The method of embodiment 1 wherein the signature sequences in the set in the set of signature sequences comprise unit norm vectors.

3. The method of embodiment 1 wherein the signature sequences in the set in the set of signature sequences are equiangular in a vector space corresponding to the signature sequence set.

4. The method of embodiment 3 wherein all elements of the signature sequences in the set in the set of signature sequences, except those corresponding to diagonal elements of a Gramian matrix corresponding to the set of signature sequences, have equal magnitude.

5. The method of claim 3 wherein all elements of the signature sequences in the set of signature sequence have unit magnitude.

6. The method of claim 1 wherein the signature sequences in the set of signature sequences are selected from equiangular sub-spaces of a vector space corresponding to the set of signature sequences, wherein each subspace corresponds to a different user.

7. The method of claim 1 wherein the signature sequences in the set of signature sequences are selected from equiangular sub-spaces of a vector space corresponding to the set of signature sequences, wherein the subspaces correspond to subsets of the signature sequences for different users.

8. The method of claim 1 wherein the signature sequences in the set of signature sequences are selected from equidistant sub-spaces of a vector space corresponding to the set of signature sequences, wherein the subspaces correspond to subsets of the signature sequences for different users.

9. The method of claim 1 1 wherein the total squared correlation of the set of signature sequences is equal to the square of the number of users divided by a length of the signature sequences.

10. The method of any of the previous claims, further comprising:

providing user data; and

forwarding the user data to a host computer via the transmission to the base station.

1 1. A method of receiving a non-orthogonal data transmission from a plurality of users, said method comprising

receiving (410) a composite signal comprising a plurality of individual uplink signals from different users on shared radio resources, wherein each uplink signal is spread with a respective signature sequence selected from a common set of signature sequence, wherein a total squared correlation for the set of signature sequences is directly proportional to the multiple access interference between users; and separating (420) the uplink signals using the corresponding signature sequences applied to the uplink signals.

12. The method of claim 1 1 wherein the signature sequences in the set of signature sequences comprise unit norm vectors.

13. The method of claim 1 1 wherein the signature sequences in the set of signature sequences are equiangular in a vector space corresponding to the signature sequence set.

14. The method of claim 13 wherein all elements of the signature sequences in the set in the set of signature sequences, except those corresponding to diagonal elements of a Gramian matrix corresponding to the set of signature sequences, have equal magnitude.

15. The method of claim 13 wherein all elements of the signature sequences in the set of signature sequence have unit magnitude.

16. The method of claim 1 1 wherein the signature sequences in the set of signature sequences are selected from equiangular sub-spaces of a vector space corresponding to the set of signature sequences, wherein each subspace corresponds to a different user.

17. The method of claim 1 1 wherein the signature sequences in the set of signature sequences are selected from equiangular sub-spaces of a vector space corresponding to the set of signature sequences, wherein the subspaces correspond to subsets of the signature sequences for different users.

18. The method of claim 1 1 wherein the signature sequences in the set of signature sequences are selected from equidistant sub-spaces of a vector space corresponding to the set of signature sequences, wherein the subspaces correspond to subsets of the signature sequences for different users.

19. The method of claim 1 1 wherein the total squared correlation of the set of signature sequences is equal to the square of the number of users divided by a length of the signature sequences.

20. The method of any of claims 11-20, further comprising:

obtaining user data; and

forwarding' the user data to a host computer or a wireless device.

21. A transmitter in a wireless communication network, said transmitter,:

a communication circuit configured for communication with one or more serving cells the wireless communication network; and

a processing circuit configured to:

obtain a non-orthogonal signature sequence selected from a set of non- orthogonal signature sequences used by two or more users transmitting simultaneously on shared resources, wherein a total squared correlation for the set of signature sequences is directly proportional to the multiple access interference between users;

spread a data signal using the obtained non-orthogonal signature sequence; and transmit the spread data signal on the shared resources .

22. The transmitter of claim 21 wherein the signature sequences in the set in the set of signature sequences comprise unit norm vectors.

23. The transmitter of claim 21 wherein the signature sequences in the set in the set of signature sequences are equiangular in a vector space corresponding to the signature sequence set.

24. The transmitter of claim 23 wherein all elements of the signature sequences in the set in the set of signature sequences, except those corresponding to diagonal elements of a Gramian matrix corresponding to the set of signature sequences, have equal magnitude.

25. The transmitter of claim 23 wherein all elements of the signature sequences in the set of signature sequence have unit magnitude.

26. The transmitter of claim 21 wherein the signature sequences in the set of signature sequences are selected from equiangular sub-spaces of a vector space corresponding to the set of signature sequences, wherein each subspace corresponds to a different user.

27. The transmitter of claim 21 wherein the signature sequences in the set of signature sequences are selected from equiangular sub-spaces of a vector space corresponding to the set of signature sequences, wherein the subspaces correspond to subsets of the signature sequences for different users.

28. The transmitter of claim 21 wherein the signature sequences in the set of signature sequences are selected from equidistant sub-spaces of a vector space corresponding to the set of signature sequences, wherein the subspaces correspond to subsets of the signature sequences for different users.

29. The transmitter of claim 21 wherein the total squared correlation of the set of signature sequences is equal to the square of the number of users divided by a length of the signature sequences.

30. A computer program comprising executable instructions that, when executed by a processing circuit in a transmitter in a wireless communication network, causes the transmitter to perform any one of the methods of claims 1 - 10.

31. A carrier containing a computer program of claim C12, wherein the carrier is one of an electronic signal, optical signal, radio signal, or computer readable storage medium.

32. A wireless device comprising:

processing circuitry configured to perform any of the steps of any of the claims 1 -10; and power supply circuitry configured to supply power to the wireless device.

33. A wireless device comprising: processing circuitry and memory, the memory containing instructions executable by the processing circuitry whereby the wireless device is configured to perform any of the steps of any of claims1-10.

34. A user equipment (UE) comprising:

an antenna configured to send and receive wireless signals;

radio front-end circuitry connected to the antenna and to processing circuitry, and

configured to condition signals communicated between the antenna and the processing circuitry;

the processing circuitry being configured to perform any of the steps of any of claims 1 - 10;

an input interface connected to the processing circuitry and configured to allow input of information into the UE to be processed by the processing circuitry; an output interface connected to the processing circuitry and configured to output

information from the UE that has been processed by the processing circuitry; and a battery connected to the processing circuitry and configured to supply power to the UE.

35. A receiver in a serving cell of the wireless communication network, said receiver comprising:

a communication circuit configured for communication with one or more transmitters in a wireless communication network; and

a processing circuit configured to:

receive a composite signal comprising a plurality of individual uplink signals from different users on shared radio resources, wherein each uplink signal is spread with a respective signature sequence selected from a common set of signature sequence, wherein a total squared correlation for the set of signature sequences is directly proportional to the multiple access interference between users; and

separate the uplink signals using the corresponding signature sequences applied to the uplink signals.

36. The receiver of claim 35 wherein the signature sequences in the set of signature sequences comprise unit norm vectors.

37. The receiver of claim 35 wherein the signature sequences in the set of signature sequences are equiangular in a vector space corresponding to the signature sequence set.

38. The receiver of claim 37 wherein all elements of the signature sequences in the set in the set of signature sequences, except those corresponding to diagonal elements of a Gramian matrix corresponding to the set of signature sequences, have equal magnitude.

39. The receiver of claim 37 wherein all elements of the signature sequences in the set of signature sequence have unit magnitude.

40. The receiver of claim 35 wherein the signature sequences in the set of signature sequences are selected from equiangular sub-spaces of a vector space corresponding to the set of signature sequences, wherein each subspace corresponds to a different user.

41. The receiver of claim 35 wherein the signature sequences in the set of signature sequences are selected from equiangular sub-spaces of a vector space corresponding to the set of signature sequences, wherein the subspaces correspond to subsets of the signature sequences for different users.

42. The receiver of claim 35 wherein the signature sequences in the set of signature sequences are selected from equidistant sub-spaces of a vector space corresponding to the set of signature sequences, wherein the subspaces correspond to subsets of the signature sequences for different users.

43. The receiver of claim 35 wherein the total squared correlation of the set of signature sequences is equal to the square of the number of users divided by a length of the signature sequences.

44. A computer program comprising executable instructions that, when executed by a processing circuit in a receiver in a wireless communication network, causes the receiver to perform any one of the methods of claims 1 1 - 20.

45. A carrier containing a computer program of claim 44, wherein the carrier is one of an electronic signal, optical signal, radio signal, or computer readable storage medium.

46. A base station configured to perform any of the steps of any of claims 1 1 -20.

Description:
WELCH BOUND SIGNATURE SEQUENCE DESIGN FOR NOMA

TECHNICAL FIELD

[001] The present disclosure relates generally to multiple access technologies and, more particularly, to non-orthogonal multiple access (NOMA) using Welch bound signature sequences.

BACKGROUND

[002] The Third Generation Partnership Project (3GPP) has performed a study item of the New Radio (NR) standard on non-orthogonal multiple access (NOMA) schemes. NOMA schemes are generally based on modulation and spreading methods that map the user data to resources that are shared among multiple users. In NOMA, transmissions from user equipment (UEs) overlap on shared time and frequency resources. By using properly designed signature sequences/vectors in order to spread the information symbols in frequency, it is possible to separate the overlapping signals from different users.. This preprocessing is carried out by repeating e.g. M-QAM information symbols over a number of possibly contiguous resource elements (REs), each with different weight and phase determined by a signature sequence (SS). The idea behind the NOMA paradigm is that the clever design of spreading vectors can facilitate the implementation of advanced multi-user detectors (MUD), such as the minimum- mean squared-error (MMSE) detector or the maximum a posteriori (MAP) detector, in order to improve the joint detection/demodulation of the superimposed user equipment (UE)

transmissions. The system can then achieve enhanced performance, in terms of sum-rate and/or number of supported UEs, when NOMA-enabled UEs are sharing the time/frequency resources and effective MUD solutions are used to separate their data signals from different UEs.

[003] Traditionally, signal transmission to or from multiple UEs in a cellular network is preferably done by ensuring, or at least attempting to ensure, orthogonality of the transmitted signals (herein referred to conventional orthogonal multiple access, COMA) via orthogonal time, frequency, or spatial allocation of the transmitted signal resources. Additionally, to account for imperfections in such allocation or in the propagation channel, restoring orthogonality is the aim of receiver procedures, using equalizers, interference rejection combining (IRC) and other MMSE-like receivers for e.g. Spread Orthogonal Frequency Division Multiplexing (S-OFDM) or multiple-input, multiple output (MIMO) transmission, but also non-linear variants of such receivers.

[004] In some scenarios, the network prioritizes the ability to handle a larger number of users over given resources than would be allowed according to the COMA approach, e.g. when the available degrees of freedom (DoFs) are fewer than the number of users to be served. Multiple users can then be scheduled in same resources, according to a NOMA approach, with the inherent realization that the users’ signals will not be substantially orthogonal at the receiver. Rather, there will exist residual inter-user interference that needs to be handled by the receiver. By the nature of NOMA transmission, multiple signals are received non-orthogonally and the overlapping signals must generally be separated by the receiver prior to decoding. To assist in that handling, it is a known technique to impose UE-specific signature sequences (SSs) on the individual UE signals. The receiver can then use the presence of the SSs to facilitate extracting the individual user signals. Another equivalent view is that invoking the SSs allows the effective end-to-end channel to be made closer to diagonal.

[005] In NOMA, each UE spreads its Quadrature Amplitude Modulation (QAM) information symbols using an N-length spreading sequence or signature sequence {s k } . Let K denote the number of simultaneously active UEs. For a base station (e.g. eNB or gNB), the received signal vectory e C N , where C denotes complex valued variables, and N is the number of REs spanned by the signature vectors and carry the same QAM information symbols, at the eNB can be written as: y = Y s k O k x k + w,

1 where h k is the channel vector between UE k and the base station, x k is the QAM symbol of UE k , and the operator O represents the pointwise multiplication/product of two vectors. For multiple receive (RX) antennas, the received signal corresponding to a single QAM symbol per UE can be formed by concatenating the /V-length received vector y from each RX antenna.

From a system performance point-of-view, it is optimal to jointly choose the transmit strategies for all UEs and then employ a joint MUD detector. Typically, the QAM symbols are spread using sequences that are designed to have certain desired correlation properties. The differences between various schemes lie in how the signature sequences are constructed.

[006] In general, the transmitter and receiver (e..g. the UE and the base station in a cellular network UL use case) are aware of the signatures used and/or their relevant properties. One way to achieve this is for the base station or other network node to inform each UE about the SS it should use, or provide other sufficient information for the UE to determine a suitable SS.

[007] Some approaches considered for SS design include pseudo-random sequences and conventional Hadamard-like spreading sequences. One aim of such considered SS designs is to provide good separation between UEs while also allowing low-complexity decoding at the receiver. However, the performance of current signature sequence designs in terms of some metrics of interest (sum rate, block error rate (BLER), etc.) is not optimal given the available resources and variable-sized sets of UEs. In other words, in the same conditions and using the same transmission resources, the network does not maximize its capacity and

transmission efficiency. [008] Furthermore, the range of NOMA transmission scenarios is broad and the current state of the art in signature sequence design schemes that are optimal in certain operating modes are not optimal in others, e.g. the number of users.

[009] There is thus a need for a signature sequence design framework that maximizes networks performance metrics of interest, or closely approaches the relevant performance limits, while adapting to changes in the transmission scenario.

SUMMARY

[010] The disclosure relates to methods of signature sequence (SS) design for NOMA transmission that optimizes a set of signature sequence vectors by jointly considering transmission system properties and effects (the number of users, the available time and frequency resources, and spatial degrees of freedom) of the candidate SS vectors or vector entries, to minimize the total inter-user interference in the resulting end-to-end system.

[011] The techniques herein described enable SS design for NOMA that maximizes aggregate performance for simultaneously scheduled users and that allows approach this optimality in a variety of transmission scenarios.

[012] According to one embodiment, a method implemented by a transmitter of non- orthogonal data transmission is provided. The method comprises obtaining a non-orthogonal signature sequence selected from a set of non-orthogonal signature sequences used by two or more users transmitting simultaneously on shared resources, wherein a total squared correlation for the set of signature sequences is directly proportional to the multiple access interference between users, spreading a data signal using the obtained non-orthogonal signature sequence and transmitting the spread data signal on the shared resources.

[013] According to another embodiment, a method of receiving a non-orthogonal data transmission from a plurality of users is provided. The method comprises receiving a composite signal comprising a plurality of individual uplink signals from different users on shared radio resources, wherein each uplink signal is spread with a respective signature sequence selected from a common set of signature sequence, and wherein a total squared correlation for the set of signature sequences is directly proportional to the multiple access interference between users. The method further comprises separating the uplink signals using the corresponding signature sequences applied to the uplink signals.

BRIEF DESCRIPTION OF THE DRAWINGS

[014] Figure 1 illustrates an exemplary wireless communication network employing NOMA according to an embodiment.

[015] Figure 2 illustrates an exemplary method of computing signature sequences used for NOMA data transmissions.

[016] Figure 3 illustrates a signature signal matrix of user k with r orthonormal columns. [017] Figure 4 illustrates a signal model for a single user.

[018] Figure 5 illustrates a method of NOMA data transmission using Welch bound signature sequences implemented by a transmitter of configuring measurement reporting for a UE in a wireless communication network.

[019] Figure 6 illustrates a method of NOMA data reception using Welch bound signature sequences implemented by a receiver (e.g. base station) in a wireless communication network.

[020] Figure 7 is a schematic block diagram of an exemplary transmitter configured to use Welch bound signature sequences for data transmission.

[021] Figure 8 is a schematic block diagram of an exemplary receiver configured to use Welch bound signature sequences for data reception.

[022] Figure 9 is a functional block diagram of a wireless terminal that can be configured as a UE or base station in a wireless communication network.

[023] Figure 10 illustrates a network node for computing the Welch bound signature sequences.

[024] Figure 1 1 illustrates a illustrates an exemplary wireless communication network employing NOMA according to one or more embodiments;

[025] Fi gure 12 illustrates one embodiment of a UE;

[026] Figure 13 is a schematic block diagram illustrating a virtualization environment;

[027] Figure 14 illustrates a telecommunication network connected via an intermediate network to a host computer in accordance with some embodiments;

[028] Figure 15 illustrates a host computer communicating via a base station with a user equipment over a partially wireless connection in accordance with some embodiments;

[029] Figures 16-19 illustrate methods implemented in a communication system, in accordance with various embodiments.

DETAILED DESCRIPTION

[030] The disclosure provides techniques NOMA transmissions in a wireless communication network using Welch bound signature sequences to enable separation of individual user signals. In some embodiments, the signature sequences may comprise vectors that are applied to a single modulation symbol. In other embodiments, the signature sequences may comprises matrices that are applied to multiple modulation symbols. The techniques are particularly useful for uplink transmissions from the UE to the network, but could also be applied to downlink transmissions. [031] The disclosure relates to methods of signature sequence (SS) design for NOMA transmission that optimizes a set of signature sequence vectors by jointly considering transmission system properties and effects (the number of users, the available time and frequency resources, and spatial degrees of freedom) of the candidate SS vectors or vector entries, to minimize the total inter-user interference in the resulting end-to-end system.

[032] In one embodiment, a metric is formulated to reach the Welch lower bound of the total sum interference power over all users. Some embodiments of metric choices that lead to Welch bound equality (WBE) can ensure equality as the number of users in the system changes. The resulting multiple-access scheme can then be referred to as WBE based spread multiple access (WSMA).

[033] The metric may comprise, for example, the post-processed signal to interference plus noise ratio (SINR) of the received data vector, the sum data rate of the active users, the sum of off-diagonal terms in a signature sequence vector inner product (Gramian) matrix, the number of non-zero terms in the Gramian, or other examples.

[034] The optimization can be performed using an iterative non-linear search algorithm. The minimization of total inter-user interference may be achieved via maximizing or minimizing a predetermined metric at each stage.

[035] The techniques herein described enable SS design for NOMA that maximizes aggregate performance for simultaneously scheduled users and that allows approach this optimality in a variety of transmission scenarios.

[036] Figure 1 illustrates NOMA transmissions from a plurality of UEs 200 to a base station 100 in one cell 20 of a wireless communication network 10. The uplink transmissions from the different UEs 200 are spread using different non-orthogonal signature sequences denoted SS1 - SS4 and overlap in time and frequency. At the receiver MUD techniques are used to separate the uplink signals and minimize inter-user interference.

[037] In exemplary embodiments, the signature sequences used by the UEs 200 or other transmitters (or users) are optimized by jointly considering transmission system properties and effects (e.g., the number of users, the available time and frequency resources, and spatial degrees of freedom, etc.) of the candidate signature sequence vectors or vector entries, to minimize the total inter-user interference in the resulting end-to-end system. In one

embodiment, a metric is formulated to reach the Welch lower bound of the total sum

interference power over all users, i.e. over all transmitting users’ received signals. Some embodiments of metric choices that lead to Welch bound equality (WBE) can ensure equality as the number of users in the system changes. The resulting multiple-access scheme can then be referred to as WBE based spread multiple access (WSMA). The metric may comprise, for example, the post-processed signal to interference plus noise ratio (SINR) of the received data vector, the sum data rate of the active users, the sum of off-diagonal terms in a signature sequence vector inner product (Gramian) matrix, or the number of non-zero terms in the Gramian matrix. The optimization can be performed using an iterative non-linear search algorithm. The minimization of total inter-user interference may be achieved via maximizing or minimizing a predetermined metric at each stage. The optimization may be performed by the UE, or by a previous offline design process, or by an online process by the network node.

[038] Design Approach

[039] One aspect of the disclosure comprises designs for the signature sequences that maximize aggregate performance for simultaneously scheduled users or user equipments and that approach this optimality in a variety of transmission scenarios.

[040] Figure 2 illustrates an exemplary method 50 for deriving signature sequences for NOMA transmission. A typical (but not exclusive) use case may be multi-user (MU) transmission in the uplink.

[041] In step 60, the network or network node 100 assesses the transmission scenario parameters, in terms of e.g. the number of UEs 200 to be served in relation to the total available resources, and/or the available degrees of freedom (DoF) in the transmission system (e.g. the spatial DoF in the form of available transmit and receive antennas and propagation channel properties, or frequency and temporal DoF in the form of available resource blocks or resource elements in time and frequency). In some embodiments, the network may also determine instantaneous channel state information or second-order statistics of the channel for the users 200 to be scheduled.

[042] In step 70, a computation algorithm is configured in accordance with the transmission scenario parameters, e.g. configuring to handle the required number of users, determining the signature sequence vector length, etc.

[043] In step 80, an appropriate optimization metric is selected, by the network node 100, that leads to minimizing the total cross-talk over all users 200 according to the Welch bound principle.

[044] In step 90, the network node 100 then computes the signature sequence vectors according to the previous algorithm selection and metric configuration. The UEs 200 to be scheduled are informed about the signature sequence they should use.

[045] Signature Sequence Computation and Application Contexts

[046] In some embodiments, one or more signature sequence sets, possibly matched to multiple transmission scenarios, are computed offline as herein described and specified in a standard specification. In operation, the network 100 may compute a preferred signature sequence for the current transmission scenario online as herein described and select one out of multiple specified signature sequence sets, or a subset of signature sequence from a single specified signature sequence set, that best match the preferred signature sequence. The best match may be determined e.g. using one of the signature sequence optimization metrics.

Alternatively, the network 100 may choose the signature sequence to use in the given scenario by evaluating the expected performance, e.g. according to one of the above-mentioned metrics, for some or all of the predetermined specified signature sequences and selecting the one(s) that maximize the performance metric. The network 100 then informs simultaneously scheduled UEs 200 which signature sequences out of the available codebook(s) they should use, e.g. by signaling indices to signature sequence codebook entries.

[047] In other embodiments, the network 100 may compute preferred signature sequence for the current transmission scenario as herein described, unconstrained by predetermined codebook contents. The network then informs UEs 200 to use the computed signature sequence, e.g. by signaling quantized versions of signature sequence vector elements or indices to lists of quantized element values.

[048] Example WBE Formulation and Optimization Criteria

[049] Various criteria can be used for deriving the signature sequence sets. Exemplary criteria include, post-processed SINR of the received data vector, sum data rate of the active users, sum of off-diagonal terms in a signature sequence vector inner product (Gramian) matrix, and number of non-zero terms in the Gramian matrix. In some embodiments, the SSs are generated simultaneously by the network node. In other embodiments, each UE can generate its own SS locally.

[050] In general, signature sequences in embodiments of the present disclosure are designed to the meet Welsh bound equality (WBE) criteria. The term WBE refers to a set of signature sequences that meet with equality the Welsh bound of total inter-sequence interference.

[051] A property common to all sequence designs in the broad class of WBE sequences is

that they all exhibit a total squared correlation (TSC) metric according to TSC =— , where K is the number of users and N is the length of the signature sequences. The TSC metric describes the total squared correlation (auto and cross-correlations) of the sequences in the group. When the TSC metric is satisfied, the TSC of the set of signature sequences is directly proportional to the multiple-access interference (MAI) experienced by the users

[052] Alternatively, the TSC metric can be converted into a limit on the total multiple-access interference (MAI) experienced by the users using the sequences -- the total residual

interference power after receiver processing over all users’ signals: MAI =—— K.

[053] Thus, WBE-based sequence set design minimizes the MAI metric over all possible signature sequence set designs. The MAI (and TSC) minimization corresponds simultaneously to maximizing the sum rate, maximizing per-user rates, and minimizing the MMSE of the received composite signal. Thus, the TSC criterion may in some embodiments be replaced by these alternative criteria.

[054] A subclass of WBE sequences is the subclass of harmonic WBE (HWBE) sequences. In this subclass, all signature sequence vectors have a unit magnitude.

[055] Another subclass of WBE sequences is the subclass of Equiangular Tight Frames (ETF) sequences. In the ETF subclass, the K signature sequence vectors of length N are placed in N- dimensional space so that the angles between any pair of vectors is equal. An ETF signature sequence set S can be further characterized by that all off-diagonal elements of the Gramian matrix S H S have equal magnitude. The ETF signature sequence set satisfies a worst-case matrix coherence criterion, minimizing the maximal inter-vector correlation.

[056] A further sub-class of the ETF signature sequences is the subclass of harmonic ETF (HETF) signature sequences where the signature sequence vectors are equiangular and have a unit magnitude.

[057] Further classes of signature sequence sets can be defined using distance properties in higher-dimensional spaces where each user is allocated a subspace. This configuration results e.g. when multiple symbols are employed for signature sequence transmission. The spectral distance-optimized sequences (EIF) subclass generalizes the ETF class, as it creates subspaces for signature sequence sets for individual users that are equiangular (instead of the signature sequence vectors themselves being equiangular).

[058] Similarly, a subclass of Chordal distance-optimized sequences generalizes the broader TSC-optimized (WBE) class to for multiple symbol transmission.

[059] The WBE-signature sequence computation procedure may be based on various optimization criteria, e.g.:

• Maximizing post-processed SINR of the received data vector

• Maximizing sum data rate of active users

• Minimizing sum of inner products of unequal signature sequence vectors

• Minimizing number of non-zero terms in the signature sequence vector inner product (Gramian) matrix.

[060] Examples of Welch Bound-Based Constructions in Different System Configurations

[061] The following description involves complex valued variables (denoted as C), so that the description provided is w.r.t. (C, unless explicitly mentioned. Though the signature sequence construction criteria in real value variables (denoted as M ) remains the same as the counter parts in C, the conditions under which each attains a certain optimality may be different.

[062] On the uplink (UL) transmission, a user k , of K active users or user equipments 200, in the network, is identified by a 5-tuple {N tx k , N te>k , N sy>k , p k , T fc , S k ), where

• N tX:k is the number of transmit antennas, i.e., spatial dimension,

• N te>k is the number of time slots, i.e., temporal dimension,

• N sy k is the number of transmit symbols,

• p fe is the transmit power vector (power domain), one element for each of the N sy k transmit symbols,

• T fe is the spatial transmit beamforming (BF) matrix (spatial domain), one column for each of the N sy k transmit symbols, • S fc is the temporal spreading signature sequence matrix (temporal domain), one column for each of the N sy k transmit symbols.

[063] These parameters provide a more general representation of the decision variables that need to be optimized. It is assumed that N te k = N, Vk, N sy c = r, \/k, and r £ N. There are K active users in the network and the receiver or the network node is equipped with N rx receive antennas. From the 5-tuple of each user, it can be said that each user is present in a subspace of different dimension both temporally {N te k ) and spatially {N tx k ). It should be noted that the time domain for the signature sequence assumed here may be equivalently addressed in any of the other domain such as frequency. But the temporal domain is retained here.

[064] Single Symbol and Single Antenna (r = 1, Vfc: N = 1: N ^ i . = 1 , Vk)

[065] If the Welch Bound (WB) on the performance indicator (PI) TSC is satisfied with equality, then the set of obtained signature sequence vectors are optimum in the overall Mean Square Error (MSE) sense (and also in the capacity sense). These are the Welch Bound Equality (WBE) sequences. Total Squared Correlation (TSC) captures the total permissible interference for each of the K active users in an overloaded system (K>N). Any change to any of signature sequence vectors will change the TSC and hence every user’s Signal to Interference plus Noise Ratio (SINR) also changes. The signature sequence design while optimizing the overall MSE can be viewed as a two-stage procedure, 1 ) construction and 2) selection. This separation into two will be evident in the subsections to follow.

[066] In general, the number of users, K , may vary in the network. Each time a user, or a UE drops out or a new user, or UE, is admitted, the existing set of WBE signature sequences are no longer valid for that given instance. A change in K will change the TSC and hence the SINR at each user. This implies reconstruction of the WBE signature sequences by obtaining the new correlation values which correspond to the Multiple Access Interference (MAI), among the signature sequence vectors for the new set of active users. So, it is reasonable to consider a design criterion such that the signature sequence vector of each user is at the same angle (equiangular or same correlation) from every other user’s signature sequence vector and select an appropriate performance indicator (PI) that captures this constraint. With such a requirement, the TSC and hence the SINR may be easily evaluated. The increase or decrease in the MAI at each user is already known, since the correlation is known at the construction stage and the signature sequence vectors have a unit norm. This is the interference invariance property of the signature sequences. For a given N and K, the signature sequence vectors are constructed only once. Large K may be assumed in the initial constructed, so that any user that joins can only select from the already evaluated signature sequence vectors. Two-stage problem at each instance is then reduced to a single-stage selection problem. [067] A suitable performance indicator (PI) is the worst-case coherence of the signature sequence matrix, given as the m(£) = max Is^S j l A lower bound (LB) on m(£) is defined by the

Bound and is given by:

K-N

NK-l) < M 2 (S).

If this bound is met with equality, then WBE signature sequences are obtained. These newly obtained signature sequence vectors are a subset of the WBE sequences obtained while minimizing the total squared correlation (TSC). To meet the LB with equality, the optimization problem must minimize m(5) , the outcome of which is a set of signature sequences where the correlation between any two vectors is the same. Such equiangular WBE signature sequences are known as Grassmannian signature sequences or Equiangular Tight Frames (ETF) signature sequences. It must be emphasized that the existence of an ETF is not guaranteed for any random combination of N and K.

[068] From the hardware point of view where the number of radio frequency (RF) chains is mostly limited to one at the users or the user equipments, it is preferable to choose a subset of ETFs called Harmonic Frames. These signature sequence vectors are relatively easy to generate. In addition to having a unit vector norm, each element in each vector will also have a unit magnitude. Such a signature sequence is constructed from the complex roots of unity.

[069] Multiple Symbols and Single Antenna (r > 1, V/r:

[070] This section extends the idea of ETF signature sequence in the previous section when each user has more than one symbol to transmit. It involves temporal multiplexing. It must be recollected that the signature sequence vectors discussed above must in a sense define a basis, i.e. , the columns s k , V/c, of the signature sequence matrix S form basis vectors. The rank of S H S for overloaded systems is limited to the temporal dimension N, showing that there can be at most N orthogonal vectors, i.e., N non-overlapping subspaces. So for K active users, packing the remaining ( K— N ) vectors is done by allowing controlled amount of interference among all the K users such that the columns of S are no longer orthogonal since S H S is not a scaled identity matrix. However, the rows of S are still orthogonal, i.e., SS H is a scaled identity matrix.

[071] This problem can be phrased as packing K subspaces, such that there is one r dimensional subspace of C N for each user k. Each subspace k has basis S k , the size which is (JV x r). The columns of S fe , Vfc, are orthonormal vectors for the subspace of user k, so S k S fc = I. This signature sequence design problem can be viewed as a subspace packing problem which basically provides upper bounds (UB) on the admissible number of users for a feasible (K, N, r) under some design criteria (like equidistant or equiangular). Feasible here again emphasizes on the existence of K signature sequence matrices in€ N x r w.r.t. the chosen metric. When Kr £ N, there can always be orthogonal columns across all K users such that the user subspaces are non-overlapping. [072] Fi gure 3 illustrates temporal multiplexing of r symbols of user k by r orthonormal vectors, that form the basis for the user’s subspace, and spreading it over N time slots.

[073] Once again, the worst-case coherence (now called worst-case block coherence) is

VK—N

defined as m(£) = max |S S j l. A LB is given as N(K-1 ^ £ 2 (S). If this bound is met with equality

(analogous to WBE), then the subspaces are known as equi-isoclinic, which is analogous to ETF in the WBE signature sequence with r = 1. So varying number of users in permitted. An UB on admissible users K in€ N for the equi-isoclinic subspaces is given as K £ ( N 2 - r 2 + 1). This can provide the user capacity, i.e., the maximum number of users the network would probably support.

[074] Since each subspace is assumed to have an orthonormal basis, from intra-user perspective, each user’s symbols are orthogonal (since once can always perform MF at the receiver).

[075] Single Symbol and Multiple Antennas (r— l. V/r: > 1 Vk)

[076] The received (and sampled) temporal signal vector (in a row form) at the receive antenna m from all the K users is:

where, for a user k, the spatial channel from all its N tx k transmit antennas to the receive antenna m is the unit norm spatial beamforming (BF) vector is t fc , the transmit power is p k , and the transmitted symbol is b k . For a spatially flat ( N rx x N tx k ) Ml MO channel H fe of user k at a given time instance, h fe m denotes all the elements in its row m. The temporally uncorrelated noise for all the users at the receive antenna m is z^. Each user must now adapt its own transmit strategy by optimizing its space time (ST) block code matrix to minimize the overall MSE. Figure 4 shows the signal model for user k.

[077] From Figure 4, it can be seen that the received signal of user k is a matrix Y k that is spread over both the spatial and temporal domains. Further, the K users’ signal received matrices will be superimposed on the UL, i.e., å£ =1 Y fe . To obtain an estimate b k for the transmit symbol b k from the composite signal å k=1 Y fc , a ST receive matrix F fe must be designed. The required orthogonality to satisfy the WBE among the temporal signature sequence vectors is perturbed by the inclusion of the spatial domain. This is because the overall effective space time (ST) channel of the spatial domain. It can be achieved in an iterative and alternate manner.

[078] Examples of Signature Sequence Computation by the Network

[079] The following examples illustrate approaches where Welch-bound-based signature sequence vectors are produced to generate codebooks and/or individual UE signature sequence vectors. The obtained signature sequences are then signaled or otherwise distributed to UEs. [080] Assume there are K single antenna users communicating with a single antenna receiver. Each user has a single symbol to transmit. This symbol modulates a temporal codeword (CW) vector, called a signature sequence (signature sequence), before transmitting the vector over iV time slots, i.e. , the symbol is spread (or repeated) over N time slots. It must be noted that this representation is a sampled baseband version of the communication process. Also, the terms signature sequence and CW are used with the same meaning here. Since all the users access the channel over the same N time slots, there is interference among them. This interference arising due to the multiple access (MA) is called Multiple Access Interference (MAI). This MA communication may be viewed as a network (NW) with N degrees of freedom (DoF) trying to serve K users, each with a required quality of service (QoS). So the design of the signature sequence so that each CW is placed at an optimal distance (or angle) from each other in the vector space. When K £ N, there can always be a collision free transmission from all the users, since there can be at least one DoF, which is a time slot, for each user for its transmission. This leads to an interference free transmission and such a MA transmission scheme is called orthogonal multiple access (OMA). With OMA there is a performance loss, which is quite visible when each user has a Quality of Service (QoS). The system capacity (SC) is also not optimal. OM) is not possible when the system is overloaded, i.e., when K > N. So the signature sequence vectors must be carefully adjusted to allow controlled interference among the users such that the Pis are optimized. Since the signature sequence vectors are no longer orthogonal, the MA scheme is known as Non-Orthogonal Multiple Access (NOMA).

[081] The signature sequence for each of the K users must be designed in such a manner that the overall mean squared error (MSE) is minimized. Choosing other performance indicator (PI) such as the signal to noise plus interference ratio (SINR) or the SC is also a possibility while considering the signature sequence design. These two Pis need to be maximized in the NW. Fortunately for an overloaded system, under certain design conditions, optimizing one PI leads to optimizing the other two Pis. To understand this another PI called total squared correlation (TSC) is introduced here which is directly related to the previously mentioned three Pis. The signature sequence is designed by optimizing (or minimizing) the TSC since the NW optimality, in the SC sense and also the overall MSE sense simultaneously, is defined by the achievable lower bounds (LB) on the TSC in an overloaded system.

[082] For a user k, let b k be the transmitted symbol that modulates a unit norm signature sequence vector s k . The signal model may be given as y = Sb + z, where z is the zero-mean additive white Gaussian noise vector with a covariance matrix I, the overall signature sequence matrix with codewords (CWs) in each of its columns is S, the transmit symbol vector is b. The transmit power of each user is set to unity, so the power control problem is not addressed here. A unit norm temporal receive filter f k , such as a matched filter (MF) or a linear MMSE filter, may be employed by the receiver to obtain an estimate b k for the transmitted symbol b k . The post processed SINR of each user is given as where trace(-) is the trace operator, v k is the noise component in the SINR y k . The trace(-) term in the denominator is the TSC, which also contains the desired unit signal power. So an additional unity term arises in the denominator. If the post processed noise is white, i.e., the noise power of each v k is the same, then the TSC can directly be used as a PI.

[083] A LB known as Welch Bound (WB) is defined for the TSC. For overloaded systems it is given as— < TSC and for the under loaded systems it is K < TSC. To meet the optimality conditions in the mentioned Pis, the bound must be satisfied by equality. In such a case, the obtained signature sequence is called a Welch Bound Equality (WBE) signature sequence. It must be noted that the SC optimality may not be achieved by the binary WBE signature sequence vectors.

[084] For the construction of the WBE signature sequences, interference avoidance (IA) techniques are used. A nice property of the IA methods is that the signature sequences can be obtained iteratively in a sequential and distributed manner. It is guaranteed that the iterations converge, since there exists a fixed-point for S that is an optimum. Though verifying if the obtained optimum is local or global is not easy. By optimum it is meant that the entire matrix S converges as an ensemble (as against each CW convergence), with the considered PI reaching the required tolerance. Hence the converged WBE CWs are not unique. At convergence, all the mentioned Pis are optimized.

[085] From the center part of the SINR equation, let R fc = ( åf =1j¹k Sj s + I), which is the correlation matrix of the interference plus noise. It can be readily identified that minimizing the denominator (or equivalently maximizing y fe ) is a Rayleigh-Quotient problem. From this, the Eigen vector corresponding to the minimum Eigen value of R fc may be considered as CW for user k, if it is assumed that f fc is matched to s fc . The fixed-point iterations start from the users choosing a random CW. In a given sequential user order, each user updates its signature sequence s k by solving the Eigen value problem while other signature sequence, s j ,j ¹ k, are kept fixed. After user k, the next user updates it’s CW in the same way by assuming the other CWs to be fixed. The iterations progress up to the final user in the order, such that in each iteration there are K updates, one for each CW in S. After the final update in the given iteration, the first user in the order restarts the updates until convergence.

[086] Again, from the center part of the SINR equation, the solution to f k can also be identified as the Generalized Eigen Value Problem (GEVP), i.e., finding a common Eigen value for the matrix pair (I, R fe ). The solution to which is the linear MMSE vector given as:

in its normalized form.

[087] Sequential iterations as mentioned before can be used, except that instead of solving the Eigen value problem, the normalized linear MMSE expression is used during updates. For this SINR maximization problem (or TSC minimization), the obtained solution to S from both the MMSE IA iterations and the Eigen vector IA iterations is the same fixed-point.

[088] In some embodiments, a Kronecker product based approach is employed to obtained (or construct) higher dimensional WBE signature sequence, i.e., higher N values, from lower dimensional WBE signature sequence. If the elements of S are binary antipodal, then WBE set is defined when N is a multiple of 4, i.e., modOV, 4) = 0. In cases with mod(/V, 4) ¹ 0, where the WB is loose, a LB known as Karystinos-Pados (KP) bound may be used instead.

[089] Data Transmission Using Signature Sequences

[090] The signature sequences derived in accordance with the procedures herein described can be used for transmitting signals from a plurality of transmitters (e.g. UEs 200) to a receiver (e.g. base station 100). The signature sequences are particularly useful for uplink transmission, but can also be used for downlink transmissions. For the uplink transmission scenario, according to some embodiments, the network node determines the signal sequences and sends or signals these to each user or UE. Each UE then transmits its data in the uplink using NOMA spreading with its signature sequence. In embodiments, the SSs are generated simultaneously by the network node. In other embodiments, each UE can generate its own SS locally.

[091] Figure 5 illustrates an exemplary method 300 of non-orthogonal data transmission implemented by a transmitter in a wireless communication system. The transmitter may, for example, comprise a UE 200. The transmitter obtains a non-orthogonal signature sequence selected from a set of non-orthogonal signature sequences used by two or more users transmitting simultaneously on shared resources (block 310). The total squared correlation for the set of signature sequences is directly proportional to the multiple access interference between users.

[092] In some embodiments, the set of signature sequences is specified in a codebook and the signature sequence is obtained or selected from the codebook. In the case of uplink transmissions by a UE 200, the network may select a signature sequence for the UE 200 and signal the selected signature sequence to the UE 200 by sending an index for the selected signature sequence. In other embodiments, the UE 200 may be provided information to enable it to select the signature sequence from the codebook.

[093] In some embodiments, the network may provide the signature sequence to the UE 200 via signaling. As one example, the network may transmit a quantized version of the signature sequence to the UE 200. [094] After the signature sequence is obtained, the transmitter uses the signature sequence to spread a data signal to be transmitted (block 320). After spreading, the transmitter transmits the spread data signal on the shared resources (block 330).

[095] In some embodiments of the method 300, the signature sequences in the set comprise unit norm vectors.

[096] In some embodiments of the method 300, the signature sequences in the set of signature sequences are equiangular in a vector space corresponding to the signature sequence set.

[097] In some embodiments of the method 300, all elements of the signature sequences in the set of signature sequences, except those corresponding to diagonal elements of a Gramian matrix corresponding to the set of signature sequences, have equal magnitude.

[098] In some embodiments of the method 300, all elements of the signature sequences in the set of signature sequences have unit magnitude.

[099] In some embodiments of the method, the signature sequences in the set of signature sequences are selected from equiangular sub-spaces of a vector space corresponding to the set of signature sequences, wherein each subspace corresponds to a different user.

[0100] In some embodiments of the method 300, the signature sequences in the set of signature sequences are selected from equiangular sub-spaces of a vector space

corresponding to the set of signature sequences, wherein the subspaces correspond to subsets of the signature sequences for different users.

[0101] In some embodiments of the method 300, the signature sequences in the set of signature sequences are selected from equidistant sub-spaces of a vector space corresponding to the set of signature sequences, wherein the subspaces correspond to subsets of the signature sequences for different users.

[0102] In some embodiments of the method 300, the total squared correlation of the set of signature sequences is equal to the square of the number of users divided by a length of the signature sequences.

[0103] Figure 6 illustrates an exemplary method 400 of non-orthogonal data reception implemented by a receiver in a wireless communication system. The receiver may, for example, comprises a base station 100 receiving simultaneous transmissions from multiple UEs 200 on shared resources. The receiver receives a composite signal comprising a plurality of individual uplink signals from different transmitters on shared radio resources, wherein each uplink signal is spread with a respective signature sequence selected from a common set of signature sequence (block 410). A total squared correlation for the set of signature sequences is directly proportional to the multiple access interference between users. The receiver separates the uplink signals using the corresponsing signature sequences applied to the respective uplink signals (block 420). [0104] In some embodiments of the method 400, the signature sequences in the set of signature sequences are equiangular in a vector space corresponding to the signature sequence set.

[0105] In some embodiments of the method 400, all elements of the signature sequences in the set of signature sequences, except those corresponding to diagonal elements of a Gramian matrix corresponding to the set of signature sequences, have equal magnitude.

[0106] In some embodiments of the method 400, all elements of the signature sequences in the set of signature sequence have unit magnitude.

[0107] In some embodiments of the method 400, the signature sequences in the set of signature sequences are selected from equiangular sub-spaces of a vector space

corresponding to the set of signature sequences, wherein each subspace corresponds to a different user.

[0108] In some embodiments of the method 400, the signature sequences in the set of signature sequences are selected from equiangular sub-spaces of a vector space

corresponding to the set of signature sequences, wherein the subspaces correspond to subsets of the signature sequences for different users.

[0109] In some embodiments of the method 400, the signature sequences in the set of signature sequences are selected from equidistant sub-spaces of a vector space corresponding to the set of signature sequences, wherein the subspaces correspond to subsets of the signature sequences for different users.

[0110] In some embodiments of the method 400, the total squared correlation of the set of signature sequences is equal to the square of the number of users divided by a length of the signature sequences.

[0111] An apparatus can perform any of the methods herein described by implementing any functional means, modules, units, or circuitry. In one embodiment, for example, the apparatuses comprise respective circuits or circuitry configured to perform the steps shown in the method figures. The circuits or circuitry in this regard may comprise circuits dedicated to performing certain functional processing and/or one or more microprocessors in conjunction with memory. For instance, the circuitry may include one or more microprocessor or microcontrollers, as well as other digital hardware, which may include Digital Signal Processors (DSPs), special-purpose digital logic, and the like. The processing circuitry may be configured to execute program code stored in memory, which may include one or several types of memory such as read-only memory (ROM), random-access memory, cache memory, flash memory devices, optical storage devices, etc. Program code stored in memory may include program instructions for executing one or more telecommunications and/or data communications protocols as well as instructions for carrying out one or more of the techniques described herein, in several embodiments. In embodiments that employ memory, the memory stores program code that, when executed by the one or more processors, carries out the techniques described herein. [0112] Figure 7 illustrates a transmitter 250, which may function as a UE 200, in accordance with one or more embodiments configured to implement the method 300 of Figure 5. The transmitter 250 comprises one or more antennas 260, an obtaining module 270, a spreading module 280 and a transmitting (TX) module 290. The various modules 270, 280, and 290 can be implemented by hardware and/or by software code that is executed by one or more processors or processing circuits. The obtaining module 270 is configured obtain a non- orthogonal signature sequence selected from a set of non-orthogonal signature sequences used by two or more users transmitting simultaneously on shared resources. The total squared correlation for the set of signature sequences is directly proportional to the multiple access interference between users. The spreading module 280 is configured to spreading a data signal using the obtained non-orthogonal signature sequence. The TX module 290 is configured to transmitting the spread data signal on the shared resources.

[0113] Figure 8 illustrates a receiver 150, which may function as a base station 100, in accordance with one or more embodiments configured to implement the method 400 of Figure 6. The receiver 150 comprises one or more antenna 160 for receiving signals, a receiving (RX) module 170, and a separating module 180. The various modules 170 and 180 can be implemented by hardware and/or by software code that is executed by a processor or processing circuit. The receiving module 170 is configured to receive a composite signal comprising a plurality of individual uplink signals from different users on shared radio resources, wherein each uplink signal is spread with a respective signature sequence selected from a common set of signature sequence. The total squared correlation for the set of signature sequences is directly proportional to the multiple access interference between users. The separating module 180 is configured to separate the uplink signals using the corresponding signature sequences applied to the uplink signals.

[0114] Figure 9 illustrates a wireless device or radio node 500 according to one embodiment that may be configured to function as a base station 100 or UE 200 as herein described. The radio node 500 comprises one or more antennas 510, a communication circuit 520, a processing circuit 530, and memory 590.

[0115] The communication circuit 520 is coupled to the antennas 510 and comprises the radio frequency (RF) circuitry needed for transmitting and receiving signals over a wireless communication channel. The processing circuit 530 controls the overall operation of the radio node 500 and processes the signals transmitted to or received by the radio node 500. Such processing includes coding and modulation of transmitted data signals, and the demodulation and decoding of received data signals. The processing circuit 530 may comprise one or more microprocessors, hardware, firmware, or a combination thereof.

[0116] Memory 540 comprises both volatile and non-volatile memory for storing computer program code and data needed by the processing circuit 530 for operation. Memory 540 may comprise any tangible, non-transitory computer-readable storage medium for storing data including electronic, magnetic, optical, electromagnetic, or semiconductor data storage.

Memory 540 stores a computer program 550 comprising executable instructions that configure the processing circuit 530 to implement methods 300 for NOMA data transmission or 400 for NOMA data reception according to Figures 5 and 6 respectively as described herein. In general, computer program instructions and configuration information are stored in a nonvolatile memory, such as a ROM, erasable programmable read only memory (EPROM) or flash memory. Temporary data generated during operation may be stored in a volatile memory, such as a random access memory (RAM). In some embodiments, computer program 550 for configuring the processing circuit 530 as herein described may be stored in a removable memory, such as a portable compact disc, portable digital video disc, or other removable media. The computer program 550 may also be embodied in a carrier such as an electronic signal, optical signal, radio signal, or computer readable storage medium.

[0117] Figure 10 illustrates a network node 600 according to one embodiment that may be configured to compute the signature sequences as herein described. The network node 600 comprises a communication circuit 610 for communication with other network nodes over a communication network, , a processing circuit 620 for computing the signature sequences as herein described, and a memory 630 for storing computer code and/or program instructions 640 that is executed by the processing circuit to perform the computations of the signature sequences. Memory 630 comprises both volatile and non-volatile memory for storing computer program code and data needed by the processing circuit 620 for operation. Memory 630 may comprise any tangible, non-transitory computer-readable storage medium for storing data including electronic, magnetic, optical, electromagnetic, or semiconductor data storage.

Memory 630 stores a computer program 640 comprising executable instructions that configure the processing circuit 620 to perform the computations as described herein. In general, computer program instructions and configuration information are stored in a non-volatile memory, such as a ROM, erasable programmable read only memory (EPROM) or flash memory. Temporary data generated during operation may be stored in a volatile memory, such as a random access memory (RAM). In some embodiments, computer program 640 for configuring the processing circuit 620 as herein described may be stored in a removable memory, such as a portable compact disc, portable digital video disc, or other removable media. The computer program 640 may also be embodied in a carrier such as an electronic signal, optical signal, radio signal, or computer readable storage medium.

[0118] Although the subject matter described herein may be implemented in any appropriate type of system using any suitable components, the embodiments disclosed herein are described in relation to a wireless network, such as the example wireless network illustrated in Figure 1 1. For simplicity, the wireless network of Figure 1 1 only depicts network 706, network nodes 760 and 760b, and WDs 710, 710b, and 710c. In practice, a wireless network may further include any additional elements suitable to support communication between wireless devices or between a wireless device and another communication device, such as a landline telephone, a service provider, or any other network node or end device. Of the illustrated components, network node 760 and wireless device (WD) 710 are depicted with additional detail. The wireless network may provide communication and other types of services to one or more wireless devices to facilitate the wireless devices’ access to and/or use of the services provided by, or via, the wireless network.

[0119] The wireless network may comprise and/or interface with any type of communication, telecommunication, data, cellular, and/or radio network or other similar type of system. In some embodiments, the wireless network may be configured to operate according to specific standards or other types of predefined rules or procedures. Thus, particular embodiments of the wireless network may implement communication standards, such as Global System for Mobile Communications (GSM), Universal Mobile Telecommunications System (UMTS), Long Term Evolution (LTE), Narrowband Internet of Things (NB-loT), and/or other suitable 2G, 3G, 4G, or 5G standards; wireless local area network (WLAN) standards, such as the IEEE 802.11 standards; and/or any other appropriate wireless communication standard, such as the

Worldwide Interoperability for Microwave Access (WiMax), Bluetooth, Z-Wave and/or ZigBee standards.

[0120] Network 706 may comprise one or more backhaul networks, core networks, IP networks, public switched telephone networks (PSTNs), packet data networks, optical networks, wide-area networks (WANs), local area networks (LANs), wireless local area networks (WLANs), wired networks, wireless networks, metropolitan area networks, and other networks to enable communication between devices.

[0121] Network node 760 and WD 710 comprise various components described in more detail below. These components work together in order to provide network node and/or wireless device functionality, such as providing wireless connections in a wireless network. In different embodiments, the wireless network may comprise any number of wired or wireless networks, network nodes, base stations, controllers, wireless devices, relay stations, and/or any other components or systems that may facilitate or participate in the communication of data and/or signals whether via wired or wireless connections.

[0122] As used herein, network node refers to equipment capable, configured, arranged and/or operable to communicate directly or indirectly with a wireless device and/or with other network nodes or equipment in the wireless network to enable and/or provide wireless access to the wireless device and/or to perform other functions (e.g., administration) in the wireless network. Examples of network nodes include, but are not limited to, access points (APs) (e.g., radio access points), base stations (BSs) (e.g., radio base stations, Node Bs, evolved Node Bs (eNBs) and NR NodeBs (gNBs)). Base stations may be categorized based on the amount of coverage they provide (or, stated differently, their transmit power level) and may then also be referred to as femto base stations, pico base stations, micro base stations, or macro base stations. A base station may be a relay node or a relay donor node controlling a relay. A network node may also include one or more (or all) parts of a distributed radio base station such as centralized digital units and/or remote radio units (RRUs), sometimes referred to as Remote Radio Heads (RRHs). Such remote radio units may or may not be integrated with an antenna as an antenna integrated radio. Parts of a distributed radio base station may also be referred to as nodes in a distributed antenna system (DAS). Yet further examples of network nodes include multi-standard radio (MSR) equipment such as MSR BSs, network controllers such as radio network controllers (RNCs) or base station controllers (BSCs), base transceiver stations (BTSs), transmission points, transmission nodes, multi-cell/multicast coordination entities (MCEs), core network nodes (e.g., MSCs, MMEs), O&M nodes, OSS nodes, SON nodes, positioning nodes (e.g., E-SMLCs), and/or MDTs. As another example, a network node may be a virtual network node as described in more detail below. More generally, however, network nodes may represent any suitable device (or group of devices) capable, configured, arranged, and/or operable to enable and/or provide a wireless device with access to the wireless network or to provide some service to a wireless device that has accessed the wireless network.

[0123] In Figure 1 1 , network node 760 includes processing circuitry 770, device readable medium 780, interface 790, auxiliary equipment 784, power source 786, power circuitry 787, and antenna 762. Although network node 760 illustrated in the example wireless network of Figure 1 1 may represent a device that includes the illustrated combination of hardware components, other embodiments may comprise network nodes with different combinations of components. It is to be understood that a network node comprises any suitable combination of hardware and/or software needed to perform the tasks, features, functions and methods disclosed herein. Moreover, while the components of network node 760 are depicted as single boxes located within a larger box, or nested within multiple boxes, in practice, a network node may comprise multiple different physical components that make up a single illustrated component (e.g., device readable medium 780 may comprise multiple separate hard drives as well as multiple RAM modules).

[0124] Similarly, network node 760 may be composed of multiple physically separate components (e.g., a NodeB component and a RNC component, or a BTS component and a BSC component, etc.), which may each have their own respective components. In certain scenarios in which network node 760 comprises multiple separate components (e.g., BTS and BSC components), one or more of the separate components may be shared among several network nodes. For example, a single RNC may control multiple NodeB’s. In such a scenario, each unique NodeB and RNC pair, may in some instances be considered a single separate network node. In some embodiments, network node 760 may be configured to support multiple radio access technologies (RATs). In such embodiments, some components may be duplicated (e.g., separate device readable medium 780 for the different RATs) and some components may be reused (e.g., the same antenna 762 may be shared by the RATs). Network node 760 may also include multiple sets of the various illustrated components for different wireless

technologies integrated into network node 760, such as, for example, GSM, WCDMA, LTE, NR, WiFi, or Bluetooth wireless technologies. These wireless technologies may be integrated into the same or different chip or set of chips and other components within network node 760.

[0125] Processing circuitry 770 is configured to perform any determining, calculating, or similar operations (e.g., certain obtaining operations) described herein as being provided by a network node. These operations performed by processing circuitry 770 may include processing information obtained by processing circuitry 770 by, for example, converting the obtained information into other information, comparing the obtained information or converted information to information stored in the network node, and/or performing one or more operations based on the obtained information or converted information, and as a result of said processing making a determination.

[0126] Processing circuitry 770 may comprise a combination of one or more of a

microprocessor, controller, microcontroller, central processing unit, digital signal processor, application-specific integrated circuit, field programmable gate array, or any other suitable computing device, resource, or combination of hardware, software and/or encoded logic operable to provide, either alone or in conjunction with other network node 760 components, such as device readable medium 780, network node 760 functionality. For example, processing circuitry 770 may execute instructions stored in device readable medium 780 or in memory within processing circuitry 770. Such functionality may include providing any of the various wireless features, functions, or benefits discussed herein. In some embodiments, processing circuitry 770 may include a system on a chip (SOC).

[0127] In some embodiments, processing circuitry 770 may include one or more of radio frequency (RF) transceiver circuitry 772 and baseband processing circuitry 774. In some embodiments, radio frequency (RF) transceiver circuitry 772 and baseband processing circuitry 774 may be on separate chips (or sets of chips), boards, or units, such as radio units and digital units. In alternative embodiments, part or all of RF transceiver circuitry 772 and baseband processing circuitry 774 may be on the same chip or set of chips, boards, or units

[0128] In certain embodiments, some or all of the functionality described herein as being provided by a network node, base station, eNB or other such network device may be performed by processing circuitry 770 executing instructions stored on device readable medium 780 or memory within processing circuitry 770. In alternative embodiments, some or all of the functionality may be provided by processing circuitry 770 without executing instructions stored on a separate or discrete device readable medium, such as in a hard-wired manner. In any of those embodiments, whether executing instructions stored on a device readable storage medium or not, processing circuitry 770 can be configured to perform the described

functionality. The benefits provided by such functionality are not limited to processing circuitry 770 alone or to other components of network node 760, but are enjoyed by network node 760 as a whole, and/or by end users and the wireless network generally.

[0129] Device readable medium 780 may comprise any form of volatile or non-volatile computer readable memory including, without limitation, persistent storage, solid-state memory, remotely mounted memory, magnetic media, optical media, random access memory (RAM), read-only memory (ROM), mass storage media (for example, a hard disk), removable storage media (for example, a flash drive, a Compact Disk (CD) or a Digital Video Disk (DVD)), and/or any other volatile or non-volatile, non-transitory device readable and/or computer-executable memory devices that store information, data, and/or instructions that may be used by processing circuitry 770. Device readable medium 780 may store any suitable instructions, data or information, including a computer program, software, an application including one or more of logic, rules, code, tables, etc. and/or other instructions capable of being executed by processing circuitry 770 and, utilized by network node 760. Device readable medium 780 may be used to store any calculations made by processing circuitry 770 and/or any data received via interface 790. In some embodiments, processing circuitry 770 and device readable medium 780 may be considered to be integrated.

[0130] Interface 790 is used in the wired or wireless communication of signalling and/or data between network node 760, network 706, and/or WDs 710. As illustrated, interface 790 comprises port(s)/terminal(s) 794 to send and receive data, for example to and from network 706 over a wired connection. Interface 790 also includes radio front end circuitry 792 that may be coupled to, or in certain embodiments a part of, antenna 762. Radio front end circuitry 792 comprises filters 798 and amplifiers 796. Radio front end circuitry 792 may be connected to antenna 762 and processing circuitry 770. Radio front end circuitry may be configured to condition signals communicated between antenna 762 and processing circuitry 770. Radio front end circuitry 792 may receive digital data that is to be sent out to other network nodes or WDs via a wireless connection. Radio front end circuitry 792 may convert the digital data into a radio signal having the appropriate channel and bandwidth parameters using a combination of filters 798 and/or amplifiers 796. The radio signal may then be transmitted via antenna 762. Similarly, when receiving data, antenna 762 may collect radio signals which are then converted into digital data by radio front end circuitry 792. The digital data may be passed to processing circuitry 770. In other embodiments, the interface may comprise different components and/or different combinations of components.

[0131] In certain alternative embodiments, network node 760 may not include separate radio front end circuitry 792, instead, processing circuitry 770 may comprise radio front end circuitry and may be connected to antenna 762 without separate radio front end circuitry 792. Similarly, in some embodiments, all or some of RF transceiver circuitry 772 may be considered a part of interface 790. In still other embodiments, interface 790 may include one or more ports or terminals 794, radio front end circuitry 792, and RF transceiver circuitry 772, as part of a radio unit (not shown), and interface 790 may communicate with baseband processing circuitry 774, which is part of a digital unit (not shown).

[0132] Antenna 762 may include one or more antennas, or antenna arrays, configured to send and/or receive wireless signals. Antenna 762 may be coupled to radio front end circuitry 790 and may be any type of antenna capable of transmitting and receiving data and/or signals wirelessly. In some embodiments, antenna 762 may comprise one or more omni-directional, sector or panel antennas operable to transmit/receive radio signals between, for example, 2 GHz and 66 GHz. An omni-directional antenna may be used to transmit/receive radio signals in any direction, a sector antenna may be used to transmit/receive radio signals from devices within a particular area, and a panel antenna may be a line of sight antenna used to

transmit/receive radio signals in a relatively straight line. In some instances, the use of more than one antenna may be referred to as MIMO. In certain embodiments, antenna 762 may be separate from network node 760 and may be connectable to network node 760 through an interface or port.

[0133] Antenna 762, interface 790, and/or processing circuitry 770 may be configured to perform any receiving operations and/or certain obtaining operations described herein as being performed by a network node. Any information, data and/or signals may be received from a wireless device, another network node and/or any other network equipment. Similarly, antenna 762, interface 790, and/or processing circuitry 770 may be configured to perform any transmitting operations described herein as being performed by a network node. Any information, data and/or signals may be transmitted to a wireless device, another network node and/or any other network equipment.

[0134] Power circuitry 787 may comprise, or be coupled to, power management circuitry and is configured to supply the components of network node 760 with power for performing the functionality described herein. Power circuitry 787 may receive power from power source 786. Power source 786 and/or power circuitry 787 may be configured to provide power to the various components of network node 760 in a form suitable for the respective components (e.g., at a voltage and current level needed for each respective component). Power source 786 may either be included in, or external to, power circuitry 787 and/or network node 760. For example, network node 760 may be connectable to an external power source (e.g., an electricity outlet) via an input circuitry or interface such as an electrical cable, whereby the external power source supplies power to power circuitry 787. As a further example, power source 786 may comprise a source of power in the form of a battery or battery pack which is connected to, or integrated in, power circuitry 787. The battery may provide backup power should the external power source fail. Other types of power sources, such as photovoltaic devices, may also be used.

[0135] Alternative embodiments of network node 760 may include additional components beyond those shown in Figure 11 that may be responsible for providing certain aspects of the network node’s functionality, including any of the functionality described herein and/or any functionality necessary to support the subject matter described herein. For example, network node 760 may include user interface equipment to allow input of information into network node 760 and to allow output of information from network node 760. This may allow a user to perform diagnostic, maintenance, repair, and other administrative functions for network node 760.

[0136] As used herein, wireless device (WD) refers to a device capable, configured, arranged and/or operable to communicate wirelessly with network nodes and/or other wireless devices. Unless otherwise noted, the term WD may be used interchangeably herein with user equipment (UE). Communicating wirelessly may involve transmitting and/or receiving wireless signals using electromagnetic waves, radio waves, infrared waves, and/or other types of signals suitable for conveying information through air. In some embodiments, a WD may be configured to transmit and/or receive information without direct human interaction. For instance, a WD may be designed to transmit information to a network on a predetermined schedule, when triggered by an internal or external event, or in response to requests from the network. Examples of a WD include, but are not limited to, a smart phone, a mobile phone, a cell phone, a voice over IP (VoIP) phone, a wireless local loop phone, a desktop computer, a personal digital assistant (PDA), a wireless cameras, a gaming console or device, a music storage device, a playback appliance, a wearable terminal device, a wireless endpoint, a mobile station, a tablet, a laptop, a laptop-embedded equipment (LEE), a laptop-mounted equipment (LME), a smart device, a wireless customer-premise equipment (CPE) a vehicle-mounted wireless terminal device, etc.. A WD may support device-to-device (D2D) communication, for example by implementing a 3GPP standard for sidelink communication, vehicle-to-vehicle (V2V), vehicle-to-infrastructure (V2I), vehicle-to-everything (V2X) and may in this case be referred to as a D2D communication device. As yet another specific example, in an Internet of Things (loT) scenario, a WD may represent a machine or other device that performs monitoring and/or measurements, and transmits the results of such monitoring and/or measurements to another WD and/or a network node. The WD may in this case be a machine-to-machine (M2M) device, which may in a 3GPP context be referred to as an MTC device. As one particular example, the WD may be a UE implementing the 3GPP narrow band internet of things (NB-loT) standard. Particular examples of such machines or devices are sensors, metering devices such as power meters, industrial machinery, or home or personal appliances (e.g. refrigerators, televisions, etc.) personal wearables (e.g., watches, fitness trackers, etc.). In other scenarios, a WD may represent a vehicle or other equipment that is capable of monitoring and/or reporting on its operational status or other functions associated with its operation. A WD as described above may represent the endpoint of a wireless connection, in which case the device may be referred to as a wireless terminal. Furthermore, a WD as described above may be mobile, in which case it may also be referred to as a mobile device or a mobile terminal.

[0137] As illustrated, wireless device 710 includes antenna 71 1 , interface 714, processing circuitry 720, device readable medium 730, user interface equipment 732, auxiliary equipment 734, power source 736 and power circuitry 737. WD 710 may include multiple sets of one or more of the illustrated components for different wireless technologies supported by WD 710, such as, for example, GSM, WCDMA, LTE, NR, WiFi, WiMAX, NB-loT, or Bluetooth wireless technologies, just to mention a few. These wireless technologies may be integrated into the same or different chips or set of chips as other components within WD 710.

[0138] Antenna 71 1 may include one or more antennas or antenna arrays, configured to send and/or receive wireless signals, and is connected to interface 714. In certain alternative embodiments, antenna 71 1 may be separate from WD 710 and be connectable to WD 710 through an interface or port. Antenna 71 1 , interface 714, and/or processing circuitry 720 may be configured to perform any receiving or transmitting operations described herein as being performed by a WD. Any information, data and/or signals may be received from a network node and/or another WD. In some embodiments, radio front end circuitry and/or antenna 71 1 may be considered an interface.

[0139] As illustrated, interface 714 comprises radio front end circuitry 712 and antenna 711. Radio front end circuitry 712 comprise one or more filters 718 and amplifiers 716. Radio front end circuitry 714 is connected to antenna 71 1 and processing circuitry 720, and is configured to condition signals communicated between antenna 71 1 and processing circuitry 720. Radio front end circuitry 712 may be coupled to or a part of antenna 711. In some embodiments, WD 710 may not include separate radio front end circuitry 712; rather, processing circuitry 720 may comprise radio front end circuitry and may be connected to antenna 71 1. Similarly, in some embodiments, some or all of RF transceiver circuitry 722 may be considered a part of interface 714. Radio front end circuitry 712 may receive digital data that is to be sent out to other network nodes or WDs via a wireless connection. Radio front end circuitry 712 may convert the digital data into a radio signal having the appropriate channel and bandwidth parameters using a combination of filters 718 and/or amplifiers 716. The radio signal may then be transmitted via antenna 71 1. Similarly, when receiving data, antenna 71 1 may collect radio signals which are then converted into digital data by radio front end circuitry 712. The digital data may be passed to processing circuitry 720. In other embodiments, the interface may comprise different components and/or different combinations of components.

[0140] Processing circuitry 720 may comprise a combination of one or more of a

microprocessor, controller, microcontroller, central processing unit, digital signal processor, application-specific integrated circuit, field programmable gate array, or any other suitable computing device, resource, or combination of hardware, software, and/or encoded logic operable to provide, either alone or in conjunction with other WD 710 components, such as device readable medium 730, WD 710 functionality. Such functionality may include providing any of the various wireless features or benefits discussed herein. For example, processing circuitry 720 may execute instructions stored in device readable medium 730 or in memory within processing circuitry 720 to provide the functionality disclosed herein. [0141] As illustrated, processing circuitry 720 includes one or more of RF transceiver circuitry 722, baseband processing circuitry 724, and application processing circuitry 726. In other embodiments, the processing circuitry may comprise different components and/or different combinations of components. In certain embodiments processing circuitry 720 of WD 710 may comprise a SOC. In some embodiments, RF transceiver circuitry 722, baseband processing circuitry 724, and application processing circuitry 726 may be on separate chips or sets of chips. In alternative embodiments, part or all of baseband processing circuitry 724 and application processing circuitry 726 may be combined into one chip or set of chips, and RF transceiver circuitry 722 may be on a separate chip or set of chips. In still alternative embodiments, part or all of RF transceiver circuitry 722 and baseband processing circuitry 724 may be on the same chip or set of chips, and application processing circuitry 726 may be on a separate chip or set of chips. In yet other alternative embodiments, part or all of RF transceiver circuitry 722, baseband processing circuitry 724, and application processing circuitry 726 may be combined in the same chip or set of chips. In some embodiments, RF transceiver circuitry 722 may be a part of interface 714. RF transceiver circuitry 722 may condition RF signals for processing circuitry 720.

[0142] In certain embodiments, some or all of the functionality described herein as being performed by a WD may be provided by processing circuitry 720 executing instructions stored on device readable medium 730, which in certain embodiments may be a computer-readable storage medium. In alternative embodiments, some or all of the functionality may be provided by processing circuitry 720 without executing instructions stored on a separate or discrete device readable storage medium, such as in a hard-wired manner. In any of those particular embodiments, whether executing instructions stored on a device readable storage medium or not, processing circuitry 720 can be configured to perform the described functionality. The benefits provided by such functionality are not limited to processing circuitry 720 alone or to other components of WD 710, but are enjoyed by WD 710 as a whole, and/or by end users and the wireless network generally.

[0143] Processing circuitry 720 may be configured to perform any determining, calculating, or similar operations (e.g., certain obtaining operations) described herein as being performed by a WD. These operations, as performed by processing circuitry 720, may include processing information obtained by processing circuitry 720 by, for example, converting the obtained information into other information, comparing the obtained information or converted information to information stored by WD 710, and/or performing one or more operations based on the obtained information or converted information, and as a result of said processing making a determination.

[0144] Device readable medium 730 may be operable to store a computer program, software, an application including one or more of logic, rules, code, tables, etc. and/or other instructions capable of being executed by processing circuitry 720. Device readable medium 730 may include computer memory (e.g., Random Access Memory (RAM) or Read Only Memory (ROM)), mass storage media (e.g., a hard disk), removable storage media (e.g., a Compact Disk (CD) or a Digital Video Disk (DVD)), and/or any other volatile or non-volatile, non-transitory device readable and/or computer executable memory devices that store information, data, and/or instructions that may be used by processing circuitry 720. In some embodiments, processing circuitry 720 and device readable medium 730 may be considered to be integrated.

[0145] User interface equipment 732 may provide components that allow for a human user to interact with WD 710. Such interaction may be of many forms, such as visual, audial, tactile, etc. User interface equipment 732 may be operable to produce output to the user and to allow the user to provide input to WD 710. The type of interaction may vary depending on the type of user interface equipment 732 installed in WD 710. For example, if WD 710 is a smart phone, the interaction may be via a touch screen; if WD 710 is a smart meter, the interaction may be through a screen that provides usage (e.g., the number of gallons used) or a speaker that provides an audible alert (e.g., if smoke is detected). User interface equipment 732 may include input interfaces, devices and circuits, and output interfaces, devices and circuits. User interface equipment 732 is configured to allow input of information into WD 710, and is connected to processing circuitry 720 to allow processing circuitry 720 to process the input information. User interface equipment 732 may include, for example, a microphone, a proximity or other sensor, keys/buttons, a touch display, one or more cameras, a USB port, or other input circuitry. User interface equipment 732 is also configured to allow output of information from WD 710, and to allow processing circuitry 720 to output information from WD 710. User interface equipment 732 may include, for example, a speaker, a display, vibrating circuitry, a USB port, a headphone interface, or other output circuitry. Using one or more input and output interfaces, devices, and circuits, of user interface equipment 732, WD 710 may communicate with end users and/or the wireless network, and allow them to benefit from the functionality described herein.

[0146] Auxiliary equipment 734 is operable to provide more specific functionality which may not be generally performed by WDs. This may comprise specialized sensors for doing

measurements for various purposes, interfaces for additional types of communication such as wired communications etc. The inclusion and type of components of auxiliary equipment 734 may vary depending on the embodiment and/or scenario.

[0147] Power source 736 may, in some embodiments, be in the form of a battery or battery pack. Other types of power sources, such as an external power source (e.g., an electricity outlet), photovoltaic devices or power cells, may also be used. WD 710 may further comprise power circuitry 737 for delivering power from power source 736 to the various parts of WD 710 which need power from power source 736 to carry out any functionality described or indicated herein. Power circuitry 737 may in certain embodiments comprise power management circuitry. Power circuitry 737 may additionally or alternatively be operable to receive power from an external power source; in which case WD 710 may be connectable to the external power source (such as an electricity outlet) via input circuitry or an interface such as an electrical power cable. Power circuitry 737 may also in certain embodiments be operable to deliver power from an external power source to power source 736. This may be, for example, for the charging of power source 736. Power circuitry 737 may perform any formatting, converting, or other modification to the power from power source 736 to make the power suitable for the respective components of WD 710 to which power is supplied.

[0148] Figure 12 illustrates one embodiment of a UE in accordance with various aspects described herein. As used herein, a user equipment or UE may not necessarily have a user in the sense of a human user who owns and/or operates the relevant device. Instead, a UE may represent a device that is intended for sale to, or operation by, a human user but which may not, or which may not initially, be associated with a specific human user (e.g., a smart sprinkler controller). Alternatively, a UE may represent a device that is not intended for sale to, or operation by, an end user but which may be associated with or operated for the benefit of a user (e.g., a smart power meter). UE 8200 may be any UE identified by the 3rd Generation

Partnership Project (3GPP), including a NB-loT UE, a machine type communication (MTC) UE, and/or an enhanced MTC (eMTC) UE. UE 800, as illustrated in Figure 12, is one example of a WD configured for communication in accordance with one or more communication standards promulgated by the 3rd Generation Partnership Project (3GPP), such as 3GPP’s GSM, UMTS, LTE, and/or 5G standards. As mentioned previously, the term WD and UE may be used interchangeable. Accordingly, although Figure 12 is a UE, the components discussed herein are equally applicable to a WD, and vice-versa.

[0149] In Figure 12, UE 800 includes processing circuitry 801 that is operatively coupled to input/output interface 805, radio frequency (RF) interface 809, network connection interface 811 , memory 815 including random access memory (RAM) 817, read-only memory (ROM) 819, and storage medium 821 or the like, communication subsystem 831 , power source 833, and/or any other component, or any combination thereof. Storage medium 821 includes operating system 823, application program 825, and data 827. In other embodiments, storage medium 821 may include other similar types of information. Certain UEs may utilize all of the

components shown in Figure 12, or only a subset of the components. The level of integration between the components may vary from one UE to another UE. Further, certain UEs may contain multiple instances of a component, such as multiple processors, memories,

transceivers, transmitters, receivers, etc.

[0150] In Figure 12, processing circuitry 801 may be configured to process computer instructions and data. Processing circuitry 801 may be configured to implement any sequential state machine operative to execute machine instructions stored as machine-readable computer programs in the memory, such as one or more hardware-implemented state machines (e.g., in discrete logic, FPGA, ASIC, etc.); programmable logic together with appropriate firmware; one or more stored program, general-purpose processors, such as a microprocessor or Digital Signal Processor (DSP), together with appropriate software; or any combination of the above. For example, the processing circuitry 801 may include two central processing units (CPUs).

Data may be information in a form suitable for use by a computer.

[0151] In the depicted embodiment, input/output interface 805 may be configured to provide a communication interface to an input device, output device, or input and output device. UE 800 may be configured to use an output device via input/output interface 805. An output device may use the same type of interface port as an input device. For example, a USB port may be used to provide input to and output from UE 800. The output device may be a speaker, a sound card, a video card, a display, a monitor, a printer, an actuator, an emitter, a smartcard, another output device, or any combination thereof. UE 800 may be configured to use an input device via input/output interface 805 to allow a user to capture information into UE 800. The input device may include a touch-sensitive or presence-sensitive display, a camera (e.g., a digital camera, a digital video camera, a web camera, etc.), a microphone, a sensor, a mouse, a trackball, a directional pad, a trackpad, a scroll wheel, a smartcard, and the like. The presence-sensitive display may include a capacitive or resistive touch sensor to sense input from a user. A sensor may be, for instance, an accelerometer, a gyroscope, a tilt sensor, a force sensor, a

magnetometer, an optical sensor, a proximity sensor, another like sensor, or any combination thereof. For example, the input device may be an accelerometer, a magnetometer, a digital camera, a microphone, and an optical sensor.

[0152] In Figure 12, RF interface 809 may be configured to provide a communication interface to RF components such as a transmitter, a receiver, and an antenna. Network connection interface 81 1 may be configured to provide a communication interface to network 843a.

Network 843a may encompass wired and/or wireless networks such as a local-area network (LAN), a wide-area network (WAN), a computer network, a wireless network, a

telecommunications network, another like network or any combination thereof. For example, network 843a may comprise a Wi-Fi network. Network connection interface 81 1 may be configured to include a receiver and a transmitter interface used to communicate with one or more other devices over a communication network according to one or more communication protocols, such as Ethernet, TCP/IP, SONET, ATM, or the like. Network connection interface 811 may implement receiver and transmitter functionality appropriate to the communication network links (e.g., optical, electrical, and the like). The transmitter and receiver functions may share circuit components, software or firmware, or alternatively may be implemented separately.

[0153] RAM 817 may be configured to interface via bus 802 to processing circuitry 801 to provide storage or caching of data or computer instructions during the execution of software programs such as the operating system, application programs, and device drivers. ROM 819 may be configured to provide computer instructions or data to processing circuitry 801. For example, ROM 819 may be configured to store invariant low-level system code or data for basic system functions such as basic input and output (I/O), startup, or reception of keystrokes from a keyboard that are stored in a non-volatile memory. Storage medium 821 may be configured to include memory such as RAM, ROM, programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), magnetic disks, optical disks, floppy disks, hard disks, removable cartridges, or flash drives. In one example, storage medium 821 may be configured to include operating system 823, application program 825 such as a web browser application, a widget or gadget engine or another application, and data file 827. Storage medium 821 may store, for use by UE 800, any of a variety of various operating systems or combinations of operating systems.

[0154] Storage medium 821 may be configured to include a number of physical drive units, such as redundant array of independent disks (RAID), floppy disk drive, flash memory, USB flash drive, external hard disk drive, thumb drive, pen drive, key drive, high-density digital versatile disc (HD-DVD) optical disc drive, internal hard disk drive, Blu-Ray optical disc drive, holographic digital data storage (HDDS) optical disc drive, external mini-dual in-line memory module (DIMM), synchronous dynamic random access memory (SDRAM), external micro-DIMM SDRAM, smartcard memory such as a subscriber identity module or a removable user identity (SIM/RUIM) module, other memory, or any combination thereof. Storage medium 821 may allow UE 800 to access computer-executable instructions, application programs or the like, stored on transitory or non-transitory memory media, to off-load data, or to upload data. An article of manufacture, such as one utilizing a communication system may be tangibly embodied in storage medium 821 , which may comprise a device readable medium.

[0155] In Figure 12, processing circuitry 801 may be configured to communicate with network 843b using communication subsystem 831. Network 843a and network 843b may be the same network or networks or different network or networks. Communication subsystem 831 may be configured to include one or more transceivers used to communicate with network 843b. For example, communication subsystem 831 may be configured to include one or more transceivers used to communicate with one or more remote transceivers of another device capable of wireless communication such as another WD, UE, or base station of a radio access network (RAN) according to one or more communication protocols, such as IEEE 802.8, CDMA, WCDMA, GSM, LTE, UTRAN, WiMax, or the like. Each transceiver may include transmitter 833 and/or receiver 835 to implement transmitter or receiver functionality, respectively, appropriate to the RAN links (e.g., frequency allocations and the like). Further, transmitter 833 and receiver 835 of each transceiver may share circuit components, software or firmware, or alternatively may be implemented separately.

[0156] In the illustrated embodiment, the communication functions of communication subsystem 831 may include data communication, voice communication, multimedia communication, short- range communications such as Bluetooth, near-field communication, location-based communication such as the use of the global positioning system (GPS) to determine a location, another like communication function, or any combination thereof. For example, communication subsystem 831 may include cellular communication, Wi-Fi communication, Bluetooth communication, and GPS communication. Network 843b may encompass wired and/or wireless networks such as a local-area network (LAN), a wide-area network (WAN), a computer network, a wireless network, a telecommunications network, another like network or any combination thereof. For example, network 843b may be a cellular network, a Wi-Fi network, and/or a near-field network. Power source 813 may be configured to provide alternating current (AC) or direct current (DC) power to components of UE 800.

[0157] The features, benefits and/or functions described herein may be implemented in one of the components of UE 800 or partitioned across multiple components of UE 800. Further, the features, benefits, and/or functions described herein may be implemented in any combination of hardware, software or firmware. In one example, communication subsystem 831 may be configured to include any of the components described herein. Further, processing circuitry 801 may be configured to communicate with any of such components over bus 802. In another example, any of such components may be represented by program instructions stored in memory that when executed by processing circuitry 801 perform the corresponding functions described herein. In another example, the functionality of any of such components may be partitioned between processing circuitry 801 and communication subsystem 831. In another example, the non-computationally intensive functions of any of such components may be implemented in software or firmware and the computationally intensive functions may be implemented in hardware.

[0158] Figure 13 is a schematic block diagram illustrating a virtualization environment 900 in which functions implemented by some embodiments may be virtualized. In the present context, virtualizing means creating virtual versions of apparatuses or devices which may include virtualizing hardware platforms, storage devices and networking resources. As used herein, virtualization can be applied to a node (e.g., a virtualized base station or a virtualized radio access node) or to a device (e.g., a UE, a wireless device or any other type of communication device) or components thereof and relates to an implementation in which at least a portion of the functionality is implemented as one or more virtual components (e.g., via one or more applications, components, functions, virtual machines or containers executing on one or more physical processing nodes in one or more networks).

[0159] In some embodiments, some or all of the functions described herein may be

implemented as virtual components executed by one or more virtual machines implemented in one or more virtual environments 900 hosted by one or more of hardware nodes 930. Further, in embodiments in which the virtual node is not a radio access node or does not require radio connectivity (e.g., a core network node), then the network node may be entirely virtualized.

[0160] The functions may be implemented by one or more applications 920 (which may alternatively be called software instances, virtual appliances, network functions, virtual nodes, virtual network functions, etc.) operative to implement some of the features, functions, and/or benefits of some of the embodiments disclosed herein. Applications 920 are run in virtualization environment 900 which provides hardware 930 comprising processing circuitry 960 and memory 990. Memory 990 contains instructions 995 executable by processing circuitry 960 whereby application 920 is operative to provide one or more of the features, benefits, and/or functions disclosed herein.

[0161] Virtualization environment 900, comprises general-purpose or special-purpose network hardware devices 930 comprising a set of one or more processors or processing circuitry 960, which may be commercial off-the-shelf (COTS) processors, dedicated Application Specific Integrated Circuits (ASICs), or any other type of processing circuitry including digital or analog hardware components or special purpose processors. Each hardware device may comprise memory 990-1 which may be non-persistent memory for temporarily storing instructions 995 or software executed by processing circuitry 960. Each hardware device may comprise one or more network interface controllers (NICs) 970, also known as network interface cards, which include physical network interface 980. Each hardware device may also include non-transitory, persistent, machine-readable storage media 990-2 having stored therein software 995 and/or instructions executable by processing circuitry 960. Software 995 may include any type of software including software for instantiating one or more virtualization layers 950 (also referred to as hypervisors), software to execute virtual machines 940 as well as software allowing it to execute functions, features and/or benefits described in relation with some embodiments described herein.

[0162] Virtual machines 940, comprise virtual processing, virtual memory, virtual networking or interface and virtual storage, and may be run by a corresponding virtualization layer 950 or hypervisor. Different embodiments of the instance of virtual appliance 920 may be implemented on one or more of virtual machines 940, and the implementations may be made in different ways.

[0163] During operation, processing circuitry 960 executes software 995 to instantiate the hypervisor or virtualization layer 950, which may sometimes be referred to as a virtual machine monitor (VMM). Virtualization layer 950 may present a virtual operating platform that appears like networking hardware to virtual machine 940.

[0164] As shown in Figure 13, hardware 930 may be a standalone network node with generic or specific components. Hardware 930 may comprise antenna 9225 and may implement some functions via virtualization. Alternatively, hardware 930 may be part of a larger cluster of hardware (e.g. such as in a data center or customer premise equipment (CPE)) where many hardware nodes work together and are managed via management and orchestration (MANO) 9100, which, among others, oversees lifecycle management of applications 920.

[0165] Virtualization of the hardware is in some contexts referred to as network function virtualization (NFV). NFV may be used to consolidate many network equipment types onto industry standard high volume server hardware, physical switches, and physical storage, which can be located in data centers, and customer premise equipment.

[0166] In the context of NFV, virtual machine 940 may be a software implementation of a physical machine that runs programs as if they were executing on a physical, non-virtualized machine. Each of virtual machines 940, and that part of hardware 930 that executes that virtual machine, be it hardware dedicated to that virtual machine and/or hardware shared by that virtual machine with others of the virtual machines 940, forms a separate virtual network elements (VNE).

[0167] Still in the context of NFV, Virtual Network Function (VNF) is responsible for handling specific network functions that run in one or more virtual machines 940 on top of hardware networking infrastructure 930 and corresponds to application 920 in Figure 13.

[0168] In some embodiments, one or more radio units 9200 that each include one or more transmitters 9220 and one or more receivers 9210 may be coupled to one or more antennas 9225. Radio units 9200 may communicate directly with hardware nodes 930 via one or more appropriate network interfaces and may be used in combination with the virtual components to provide a virtual node with radio capabilities, such as a radio access node or a base station.

[0169] In some embodiments, some signalling can be effected with the use of control system 9230 which may alternatively be used for communication between the hardware nodes 930 and radio units 9200.

[0170] Figure 14 illustrates a telecommunication network connected via an intermediate network to a host computer in accordance with some embodiments. In particular, with reference to Figure 14, in accordance with an embodiment, a communication system includes

telecommunication network 1010, such as a 3GPP-type cellular network, which comprises access network 101 1 , such as a radio access network, and core network 1014. Access network 101 1 comprises a plurality of base stations 1012a, 1012b, 1012c, such as NBs, eNBs, gNBs or other types of wireless access points, each defining a corresponding coverage area 1013a, 1013b, 1013c. Each base station 1012a, 1012b, 1012c is connectable to core network 1014 over a wired or wireless connection 1015. A first UE 1091 located in coverage area 1013c is configured to wirelessly connect to, or be paged by, the corresponding base station 1012c. A second UE 1092 in coverage area 1013a is wirelessly connectable to the corresponding base station 1012a. While a plurality of UEs 1091 , 1092 are illustrated in this example, the disclosed embodiments are equally applicable to a situation where a sole UE is in the coverage area or where a sole UE is connecting to the corresponding base station 1012.

[0171] Telecommunication network 1010 is itself connected to host computer 1030, which may be embodied in the hardware and/or software of a standalone server, a cloud-implemented server, a distributed server or as processing resources in a server farm. Host computer 1030 may be under the ownership or control of a service provider, or may be operated by the service provider or on behalf of the service provider. Connections 1021 and 1022 between telecommunication network 1010 and host computer 1030 may extend directly from core network 1014 to host computer 1030 or may go via an optional intermediate network 1020. Intermediate network 1020 may be one of, or a combination of more than one of, a public, private or hosted network; intermediate network 1020, if any, may be a backbone network or the Internet; in particular, intermediate network 1020 may comprise two or more sub-networks (not shown).

[0172] The communication system of Figure 14 as a whole enables connectivity between the connected UEs 1091 , 1092 and host computer 1030. The connectivity may be described as an over-the-top (OTT) connection 1050. Host computer 1030 and the connected UEs 1091 , 1092 are configured to communicate data and/or signaling via OTT connection 1050, using access network 101 1 , core network 1014, any intermediate network 1020 and possible further infrastructure (not shown) as intermediaries. OTT connection 1050 may be transparent in the sense that the participating communication devices through which OTT connection 1050 passes are unaware of routing of uplink and downlink communications. For example, base station 1012 may not or need not be informed about the past routing of an incoming downlink communication with data originating from host computer 1030 to be forwarded (e.g., handed over) to a connected UE 1091. Similarly, base station 1012 need not be aware of the future routing of an outgoing uplink communication originating from the UE 1091 towards the host computer 1030.

[0173] Example implementations, in accordance with an embodiment, of the UE, base station and host computer discussed in the preceding paragraphs will now be described with reference to Figure 15. Figure 15 illustrates host computer communicating via a base station with a user equipment over a partially wireless connection in accordance with some embodiments In communication system 1 100, host computer 1 1 10 comprises hardware 1 1 15 including communication interface 1 1 16 configured to set up and maintain a wired or wireless connection with an interface of a different communication device of communication system 1 100. Host computer 1 1 10 further comprises processing circuitry 1 118, which may have storage and/or processing capabilities. In particular, processing circuitry 1 118 may comprise one or more programmable processors, application-specific integrated circuits, field programmable gate arrays or combinations of these (not shown) adapted to execute instructions. Host computer 1 110 further comprises software 1 1 11 , which is stored in or accessible by host computer 11 10 and executable by processing circuitry 1 118. Software 11 1 1 includes host application 1 112. Host application 1 112 may be operable to provide a service to a remote user, such as UE 1130 connecting via OTT connection 1150 terminating at UE 1130 and host computer 11 10. In providing the service to the remote user, host application 11 12 may provide user data which is transmitted using OTT connection 1150.

[0174] Communication system 1 100 further includes base station 1 120 provided in a telecommunication system and comprising hardware 1 125 enabling it to communicate with host computer 1 1 10 and with UE 1130. Hardware 1125 may include communication interface 1126 for setting up and maintaining a wired or wireless connection with an interface of a different communication device of communication system 1100, as well as radio interface 1 127 for setting up and maintaining at least wireless connection 1 170 with UE 1 130 located in a coverage area (not shown in Figure 15) served by base station 1 120. Communication interface 1 126 may be configured to facilitate connection 1 160 to host computer 1 110. Connection 1160 may be direct or it may pass through a core network (not shown in Figure 15) of the

telecommunication system and/or through one or more intermediate networks outside the telecommunication system. In the embodiment shown, hardware 1 125 of base station 1 120 further includes processing circuitry 1 128, which may comprise one or more programmable processors, application-specific integrated circuits, field programmable gate arrays or combinations of these (not shown) adapted to execute instructions. Base station 1 120 further has software 1 121 stored internally or accessible via an external connection.

[0175] Communication system 1 100 further includes UE 1 130 already referred to. Its hardware 1 135 may include radio interface 1137 configured to set up and maintain wireless connection 1 170 with a base station serving a coverage area in which UE 1 130 is currently located.

Hardware 1 135 of UE 1 130 further includes processing circuitry 1138, which may comprise one or more programmable processors, application-specific integrated circuits, field programmable gate arrays or combinations of these (not shown) adapted to execute instructions. UE 1 130 further comprises software 1 131 , which is stored in or accessible by UE 1 130 and executable by processing circuitry 1 138. Software 1 131 includes client application 1132. Client application 1 132 may be operable to provide a service to a human or non-human user via UE 1 130, with the support of host computer 11 10. In host computer 1 110, an executing host application 1 1 12 may communicate with the executing client application 1132 via OTT connection 1 150 terminating at UE 1 130 and host computer 1 110. In providing the service to the user, client application 1 132 may receive request data from host application 1 112 and provide user data in response to the request data. OTT connection 1150 may transfer both the request data and the user data. Client application 1 132 may interact with the user to generate the user data that it provides.

[0176] It is noted that host computer 1 110, base station 1120 and UE 1 130 illustrated in Figure 15 may be similar or identical to host computer 1030, one of base stations 1012a, 1012b, 1012c and one of UEs 1091 , 1092 of Figure 14, respectively. This is to say, the inner workings of these entities may be as shown in Figure 15 and independently, the surrounding network topology may be that of Figure 14.

[0177] In Figure 15, OTT connection 1 150 has been drawn abstractly to illustrate the communication between host computer 1 110 and UE 1 130 via base station 1120, without explicit reference to any intermediary devices and the precise routing of messages via these devices. Network infrastructure may determine the routing, which it may be configured to hide from UE 1 130 or from the service provider operating host computer 1 110, or both. While OTT connection 1150 is active, the network infrastructure may further take decisions by which it dynamically changes the routing (e.g., on the basis of load balancing consideration or reconfiguration of the network).

[0178] Wireless connection 1 170 between UE 1 130 and base station 1 120 is in accordance with the teachings of the embodiments described throughout this disclosure. 290ne or more of the various embodiments improve the performance of OTT services provided to UE 1130 using OTT connection 1 150, in which wireless connection 1170 forms the last segment. More precisely, the teachings of these embodiments may reduce multi-user interference in NOMA scenarios and thereby improve the capacity and spectral efficiency of the wireless network.

[0179] A measurement procedure may be provided for the purpose of monitoring data rate, latency and other factors on which the one or more embodiments improve. There may further be an optional network functionality for reconfiguring OTT connection 1 150 between host computer 1 1 10 and UE 1130, in response to variations in the measurement results. The measurement procedure and/or the network functionality for reconfiguring OTT connection 1 150 may be implemented in software 1 1 11 and hardware 1 115 of host computer 1 110 or in software 1 131 and hardware 1 135 of UE 1 130, or both. In embodiments, sensors (not shown) may be deployed in or in association with communication devices through which OTT connection 1 150 passes; the sensors may participate in the measurement procedure by supplying values of the monitored quantities exemplified above, or supplying values of other physical quantities from which software 1 11 1 , 1131 may compute or estimate the monitored quantities. The

reconfiguring of OTT connection 1 150 may include message format, retransmission settings, preferred routing etc.; the reconfiguring need not affect base station 1120, and it may be unknown or imperceptible to base station 1 120. Such procedures and functionalities may be known and practiced in the art. In certain embodiments, measurements may involve proprietary UE signaling facilitating host computer 1 110’s measurements of throughput, propagation times, latency and the like. The measurements may be implemented in that software 11 1 1 and 1131 causes messages to be transmitted, in particular empty or‘dummy’ messages, using OTT connection 1150 while it monitors propagation times, errors etc.

[0180] Figure 16 is a flowchart illustrating a method implemented in a communication system, in accordance with one embodiment. The communication system includes a host computer, a base station and a UE which may be those described with reference to Figures 14 and 15. For simplicity of the present disclosure, only drawing references to Figure 16 will be included in this section. In step 1610, the host computer provides user data. In substep 1611 (which may be optional) of step 1610, the host computer provides the user data by executing a host application. In step 1620, the host computer initiates a transmission carrying the user data to the UE. In step 1630 (which may be optional), the base station transmits to the UE the user data which was carried in the transmission that the host computer initiated, in accordance with the teachings of the embodiments described throughout this disclosure. In step 1640 (which may also be optional), the UE executes a client application associated with the host application executed by the host computer.

[0181] Figure 17 is a flowchart illustrating a method implemented in a communication system, in accordance with one embodiment. The communication system includes a host computer, a base station and a UE which may be those described with reference to Figures 14 and 15. For simplicity of the present disclosure, only drawing references to Figure 17 will be included in this section. In step 1710 of the method, the host computer provides user data. In an optional substep (not shown) the host computer provides the user data by executing a host application.

In step 1720, the host computer initiates a transmission carrying the user data to the UE. The transmission may pass via the base station, in accordance with the teachings of the

embodiments described throughout this disclosure. In step 1730 (which may be optional), the UE receives the user data carried in the transmission.

[0182] Figure 18 is a flowchart illustrating a method implemented in a communication system, in accordance with one embodiment. The communication system includes a host computer, a base station and a UE which may be those described with reference to Figures 14 and 15. For simplicity of the present disclosure, only drawing references to Figure 18 will be included in this section. In step 1810 (which may be optional), the UE receives input data provided by the host computer. Additionally or alternatively, in step 1820, the UE provides user data. In substep 1821 (which may be optional) of step 1820, the UE provides the user data by executing a client application. In substep 181 1 (which may be optional) of step 1810, the UE executes a client application which provides the user data in reaction to the received input data provided by the host computer. In providing the user data, the executed client application may further consider user input received from the user. Regardless of the specific manner in which the user data was provided, the UE initiates, in substep 1830 (which may be optional), transmission of the user data to the host computer. In step 1840 of the method, the host computer receives the user data transmitted from the UE, in accordance with the teachings of the embodiments described throughout this disclosure.

[0183] Fi gure 19 is a flowchart illustrating a method implemented in a communication system, in accordance with one embodiment. The communication system includes a host computer, a base station and a UE which may be those described with reference to Figures 14 and 15. For simplicity of the present disclosure, only drawing references to Figure 19 will be included in this section. In step 1910 (which may be optional), in accordance with the teachings of the embodiments described throughout this disclosure, the base station receives user data from the UE. In step 1920 (which may be optional), the base station initiates transmission of the received user data to the host computer. In step 1930 (which may be optional), the host computer receives the user data carried in the transmission initiated by the base station.

[0184] Any appropriate steps, methods, features, functions, or benefits disclosed herein may be performed through one or more functional units or modules of one or more virtual apparatuses. Each virtual apparatus may comprise a number of these functional units. These functional units may be implemented via processing circuitry, which may include one or more microprocessor or microcontrollers, as well as other digital hardware, which may include digital signal processors (DSPs), special-purpose digital logic, and the like. The processing circuitry may be configured to execute program code stored in memory, which may include one or several types of memory such as read-only memory (ROM), random-access memory (RAM), cache memory, flash memory devices, optical storage devices, etc. Program code stored in memory includes program instructions for executing one or more telecommunications and/or data

communications protocols as well as instructions for carrying out one or more of the techniques described herein. In some implementations, the processing circuitry may be used to cause the respective functional unit to perform corresponding functions according one or more

embodiments of the present disclosure.

[0185] Generally, all terms used herein are to be interpreted according to their ordinary meaning in the relevant technical field, unless a different meaning is clearly given and/or is implied from the context in which it is used. All references to a/an/the element, apparatus, component, means, step, etc. are to be interpreted openly as referring to at least one instance of the element, apparatus, component, means, step, etc., unless explicitly stated otherwise. The steps of any methods disclosed herein do not have to be performed in the exact order disclosed, unless a step is explicitly described as following or preceding another step and/or where it is implicit that a step must follow or precede another step. Any feature of any of the embodiments disclosed herein may be applied to any other embodiment, wherever appropriate. Likewise, any advantage of any of the embodiments may apply to any other embodiments, and vice versa. Other objectives, features and advantages of the enclosed embodiments will be apparent from the description.

[0186] The term unit may have conventional meaning in the field of electronics, electrical devices and/or electronic devices and may include, for example, electrical and/or electronic circuitry, devices, modules, processors, memories, logic solid state and/or discrete devices, computer programs or instructions for carrying out respective tasks, procedures, computations, outputs, and/or displaying functions, and so on, as such as those that are described herein.

[0187] Representative embodiments of the disclosure are described below:

GROUP A EMBODIMENTS

A1 . A method implemented by a transmitter of non-orthogonal data transmission, said method comprising:

obtaining a non-orthogonal signature sequence selected from a set of non-orthogonal signature sequences used by two or more users transmitting simultaneously on shared resources, wherein a total squared correlation for the set of signature sequences is directly proportional to the multiple access interference between users; spreading a data signal using the obtained non-orthogonal signature sequence; and transmitting the spread data signal on the shared resources.

A2. The method of embodiment A1 wherein the signature sequences in the set in the set of signature sequences comprise unit norm vectors.

A3. The method of embodiment A1 wherein the signature sequences in the set in the set of signature sequences are equiangular in a vector space corresponding to the signature sequence set.

A4. The method of embodiment A3 wherein all elements of the signature sequences in the set in the set of signature sequences, except those corresponding to diagonal elements of a Gramian matrix corresponding to the set of signature sequences, have equal magnitude.

A5. The method of embodiment A3 wherein all elements of the signature sequences in the set of signature sequence have unit magnitude.

A6. The method of embodiment A1 wherein the signature sequences in the set of signature sequences are selected from equiangular sub-spaces of a vector space corresponding to the set of signature sequences, wherein each subspace corresponds to a different user.

A7. The method of embodiment A1 wherein the signature sequences in the set of signature sequences are selected from equiangular sub-spaces of a vector space corresponding to the set of signature sequences, wherein the subspaces correspond to subsets of the signature sequences for different users.

A8. The method of embodiment A1 wherein the signature sequences in the set of signature sequences are selected from equidistant sub-spaces of a vector space corresponding to the set of signature sequences, wherein the subspaces correspond to subsets of the signature sequences for different users.

A9. The method of embodiment A1 wherein the total squared correlation of the set of signature sequences is equal to the square of the number of users divided by a length of the signature sequences.

A10. The method of any of the previous embodiments, further comprising:

providing user data; and

forwarding the user data to a host computer via the transmission to the base station. GROUP B EMBODIMENTS

B1 . A method of receiving a non-orthogonal data transmission from a plurality of users, said method comprising

receiving a composite signal comprising a plurality of individual uplink signals from

different users on shared radio resources, wherein each uplink signal is spread with a respective signature sequence selected from a common set of signature sequence, wherein a total squared correlation for the set of signature sequences is directly proportional to the multiple access interference between users; and separating the uplink signals using the corresponding signature sequences applied to the uplink signals.

B2. The method of embodiment B1 wherein the signature sequences in the set of signature sequences comprise unit norm vectors.

B3. The method of embodiment B1 wherein the signature sequences in the set of signature sequences are equiangular in a vector space corresponding to the signature sequence set.

B4. The method of claim B3 wherein all elements of the signature sequences in the set in the set of signature sequences, except those corresponding to diagonal elements of a Gramian matrix corresponding to the set of signature sequences, have equal magnitude.

B5. The method of embodiment B3 wherein all elements of the signature sequences in the set of signature sequence have unit magnitude.

B6. The method of embodiment B1 wherein the signature sequences in the set of signature sequences are selected from equiangular sub-spaces of a vector space corresponding to the set of signature sequences, wherein each subspace corresponds to a different user.

B7. The method of embodiment B1 wherein the signature sequences in the set of signature sequences are selected from equiangular sub-spaces of a vector space corresponding to the set of signature sequences, wherein the subspaces correspond to subsets of the signature sequences for different users.

B8. The method of embodiment B1 wherein the signature sequences in the set of signature sequences are selected from equidistant sub-spaces of a vector space corresponding to the set of signature sequences, wherein the subspaces correspond to subsets of the signature sequences for different users.

B9. The method of embodiment B1 wherein the total squared correlation of the set of signature sequences is equal to the square of the number of users divided by a length of the signature sequences.

B10. The method of any of embodiments B1 to B9, further comprising:

obtaining user data; and

forwarding ' the user data to a host computer or a wireless device.

GROUP C EMBODIMENTS

C1 . A transmitter in a wireless communication network, said transmitter comprising:

a communication circuit configured for communication with one or more serving cells the wireless communication network; and

a processing circuit configured to:

obtain a non-orthogonal signature sequence selected from a set of non- orthogonal signature sequences used by two or more users transmitting simultaneously on shared resources, wherein a total squared correlation for the set of signature sequences is directly proportional to the multiple access interference between users; spread a data signal using the obtained non-orthogonal signature sequence; and transmit the spread data signal on the shared resources.

C2. The transmitter of embodiment C1 wherein the signature sequences in the set in the set of signature sequences comprise unit norm vectors.

C3. The transmitter of embodiment C1 wherein the signature sequences in the set in the set of signature sequences are equiangular in a vector space corresponding to the signature sequence set.

C4. The transmitter of claim C3 wherein all elements of the signature sequences in the set in the set of signature sequences, except those corresponding to diagonal elements of a Gramian matrix corresponding to the set of signature sequences, have equal magnitude.

C5. The transmitter of embodiment C3 wherein all elements of the signature sequences in the set of signature sequence have unit magnitude.

C6. The transmitter of embodiment C1 wherein the signature sequences in the set of signature sequences are selected from equiangular sub-spaces of a vector space

corresponding to the set of signature sequences, wherein each subspace corresponds to a different user.

C7. The transmitter of embodiment C1 wherein the signature sequences in the set of signature sequences are selected from equiangular sub-spaces of a vector space

corresponding to the set of signature sequences, wherein the subspaces correspond to subsets of the signature sequences for different users.

C8. The transmitter of embodiment C1 wherein the signature sequences in the set of signature sequences are selected from equidistant sub-spaces of a vector space corresponding to the set of signature sequences, wherein the subspaces correspond to subsets of the signature sequences for different users.

C9. The transmitter of embodiment C1 wherein the total squared correlation of the set of signature sequences is equal to the square of the number of users divided by a length of the signature sequences.

C10. A transmitter in a wireless communication network, said transmitter comprising, said transmitter comprising:

a communication circuit configured for communication with a receiver in the wireless communication network; and

a processing circuit configured to:

obtain a non-orthogonal signature sequence selected from a set of non- orthogonal signature sequences used by two or more users transmitting simultaneously on shared resources, wherein a total squared correlation for the set of signature sequences is directly proportional to the multiple access interference between users;

spread a data signal using the obtained non-orthogonal signature sequence; and transmit the spread data signal on the shared resources.

C1 1. The transmitter of embodiment C10 configured to perform any one of the methods of embodiments A2-A10.

C12. A computer program comprising executable instructions that, when executed by a processing circuit in a transmitter in a wireless communication network, causes the transmitter to perform any one of the methods of embodiments A1 - A10.

C13. A carrier containing a computer program of embodiment C12, wherein the carrier is one of an electronic signal, optical signal, radio signal, or computer readable storage medium.

C14. A non-transitory computer-readable storage medium containing a computer program comprising executable instructions that, when executed by a processing circuit in a transmitter in a wireless communication network causes the transmitter to perform any one of the methods of embodiments A1 - A10.

C15. A wireless device comprising:

processing circuitry configured to perform any of the steps of any of the Group A

embodiments; and

power supply circuitry configured to supply power to the wireless device.

C16. A wireless device comprising:

processing circuitry and memory, the memory containing instructions executable by the processing circuitry whereby the wireless device is configured to perform any of the steps of any of the Group A embodiments.

C17. A user equipment (UE) comprising:

an antenna configured to send and receive wireless signals;

radio front-end circuitry connected to the antenna and to processing circuitry, and

configured to condition signals communicated between the antenna and the processing circuitry;

the processing circuitry being configured to perform any of the steps of any of the Group A embodiments;

an input interface connected to the processing circuitry and configured to allow input of information into the UE to be processed by the processing circuitry; an output interface connected to the processing circuitry and configured to output

information from the UE that has been processed by the processing circuitry; and a battery connected to the processing circuitry and configured to supply power to the UE.

C18. A computer program comprising instructions which, when executed by at least one processor of a wireless device, causes the wireless device to carry out the steps of any of the Group A embodiments.

C19. A carrier containing the computer program of embodiment C18, wherein the carrier is one of an electronic signal, optical signal, radio signal, or computer readable storage medium. GROUP D EMBODIMENTS

D1 . A receiver in a serving cell of the wireless communication network, said receiver comprising:

a communication circuit configured for communication with one or more transmitters in a wireless communication network; and

a processing circuit configured to:

receive a composite signal comprising a plurality of individual uplink signals from different users on shared radio resources, wherein each uplink signal is spread with a respective signature sequence selected from a common set of signature sequence, wherein a total squared correlation for the set of signature sequences is directly proportional to the multiple access interference between users; and

separate the uplink signals using the corresponding signature sequences applied to the uplink signals.

D2. The receiver of embodiment D1 wherein the signature sequences in the set of signature sequences comprise unit norm vectors.

D3. The receiver of embodiment D1 wherein the signature sequences in the set of signature sequences are equiangular in a vector space corresponding to the signature sequence set.

D4. The receiver of claim D3 wherein all elements of the signature sequences in the set in the set of signature sequences, except those corresponding to diagonal elements of a Gramian matrix corresponding to the set of signature sequences, have equal magnitude.

D5. The receiver of embodiment D3 wherein all elements of the signature sequences in the set of signature sequence have unit magnitude.

D6. The receiver of embodiment D1 wherein the signature sequences in the set of signature sequences are selected from equiangular sub-spaces of a vector space corresponding to the set of signature sequences, wherein each subspace corresponds to a different user.

D7. The receiver of embodiment D1 wherein the signature sequences in the set of signature sequences are selected from equiangular sub-spaces of a vector space corresponding to the set of signature sequences, wherein the subspaces correspond to subsets of the signature sequences for different users.

D8. The receiver of embodiment D1 wherein the signature sequences in the set of signature sequences are selected from equidistant sub-spaces of a vector space corresponding to the set of signature sequences, wherein the subspaces correspond to subsets of the signature sequences for different users.

D9. The receiver of embodiment D1 wherein the total squared correlation of the set of signature sequences is equal to the square of the number of users divided by a length of the signature sequences. D10. A receiver in a serving cell of the wireless communication network, said receiver configured to:

receive a composite signal comprising a plurality of individual uplink signals from

different users on shared radio resources, wherein each uplink signal is spread with a respective signature sequence selected from a common set of signature sequence, wherein a total squared correlation for the set of signature sequences is directly proportional to the multiple access interference between users; and separate the uplink signals using the corresponding signature sequences applied to the uplink signals.

D1 1. The receiver of embodiment D10 configured to perform any one of the methods of embodiments B2-B10.

D12. A computer program comprising executable instructions that, when executed by a processing circuit in a receiver in a wireless communication network, causes the receiver to perform any one of the methods of embodiments B1 - B10.

D13. A carrier containing a computer program of embodiment D12, wherein the carrier is one of an electronic signal, optical signal, radio signal, or computer readable storage medium.

D14. A non-transitory computer-readable storage medium containing a computer program comprising executable instructions that, when executed by a processing circuit in a receiver in a wireless communication network causes the receiver to perform any one of the methods of embodiments B1 - B10.

D15. A base station configured to perform any of the steps of any of the Group B

embodiments.

D15. A base station comprising:

processing circuitry configured to perform any of the steps of any of the Group B

embodiments;

power supply circuitry configured to supply power to the base station.

D16. A base station comprising:

processing circuitry and memory, the memory containing instructions executable by the processing circuitry whereby the base station is configured to perform any of the steps of any of the Group B embodiments.

D17. A computer program comprising instructions which, when executed by at least one processor of a base station, causes the base station to carry out the steps of any of the Group B embodiments.

D18. A carrier containing the computer program of embodiment C10, wherein the carrier is one of an electronic signal, optical signal, radio signal, or computer readable storage medium. GROUP E EMBODIMENTS E1 . A communication system including a host computer comprising:

processing circuitry configured to provide user data; and

a communication interface configured to forward the user data to a cellular network for transmission to a user equipment (UE),

wherein the cellular network comprises a base station having a radio interface and

processing circuitry, the base station’s processing circuitry configured to perform any of the steps of any of the Group B embodiments.

E2. The communication system of the pervious embodiment further including the base station.

E3. The communication system of the previous 2 embodiments, further including the UE, wherein the UE is configured to communicate with the base station.

E4. The communication system of the previous 3 embodiments, wherein:

the processing circuitry of the host computer is configured to execute a host application, thereby providing the user data; and

the UE comprises processing circuitry configured to execute a client application

associated with the host application.

E5. A method implemented in a communication system including a host computer, a base station and a user equipment (UE), the method comprising:

at the host computer, providing user data; and

at the host computer, initiating a transmission carrying the user data to the UE via a cellular network comprising the base station, wherein the base station performs any of the steps of any of the Group B embodiments.

E6. The method of the previous embodiment, further comprising, at the base station, transmitting the user data.

E7. The method of the previous 2 embodiments, wherein the user data is provided at the host computer by executing a host application, the method further comprising, at the UE, executing a client application associated with the host application.

E8. A user equipment (UE) configured to communicate with a base station, the UE comprising a radio interface and processing circuitry configured to perform any of the previous 3 embodiments.

E9. A communication system including a host computer comprising:

processing circuitry configured to provide user data; and

a communication interface configured to forward user data to a cellular network for transmission to a user equipment (UE),

wherein the UE comprises a radio interface and processing circuitry, the UE’s

components configured to perform any of the steps of any of the Group A embodiments.

E10. The communication system of the previous embodiment, wherein the cellular network further includes a base station configured to communicate with the UE.

E1 1. The communication system of the previous 2 embodiments, wherein:

the processing circuitry of the host computer is configured to execute a host application, thereby providing the user data; and

the UE’s processing circuitry is configured to execute a client application associated with the host application.

E12. A method implemented in a communication system including a host computer, a base station and a user equipment (UE), the method comprising:

at the host computer, providing user data; and

at the host computer, initiating a transmission carrying the user data to the UE via a cellular network comprising the base station, wherein the UE performs any of the steps of any of the Group A embodiments.

E13. The method of the previous embodiment, further comprising at the UE, receiving the user data from the base station.

E14. A communication system including a host computer comprising:

communication interface configured to receive user data originating from a transmission from a user equipment (UE) to a base station,

wherein the UE comprises a radio interface and processing circuitry, the UE’s

processing circuitry configured to perform any of the steps of any of the Group A embodiments.

E15. The communication system of the previous embodiment, further including the UE.

E16. The communication system of the previous 2 embodiments, further including the base station, wherein the base station comprises a radio interface configured to communicate with the UE and a communication interface configured to forward to the host computer the user data carried by a transmission from the UE to the base station.

E17. The communication system of the previous 3 embodiments, wherein:

the processing circuitry of the host computer is configured to execute a host application; and

the UE’s processing circuitry is configured to execute a client application associated with the host application, thereby providing the user data. E18. The communication system of the previous 4 embodiments, wherein:

the processing circuitry of the host computer is configured to execute a host application, thereby providing request data; and

the UE’s processing circuitry is configured to execute a client application associated with the host application, thereby providing the user data in response to the request data.

E19. A method implemented in a communication system including a host computer, a base station and a user equipment (UE), the method comprising:

at the host computer, receiving user data transmitted to the base station from the UE, wherein the UE performs any of the steps of any of the Group A embodiments. E20. The method of the previous embodiment, further comprising, at the UE, providing the user data to the base station.

E21. The method of the previous 2 embodiments, further comprising:

at the UE, executing a client application, thereby providing the user data to be

transmitted; and

at the host computer, executing a host application associated with the client application. E22. The method of the previous 3 embodiments, further comprising:

at the UE, executing a client application; and

at the UE, receiving input data to the client application, the input data being provided at the host computer by executing a host application associated with the client application,

wherein the user data to be transmitted is provided by the client application in response to the input data.

E23. A communication system including a host computer comprising a communication interface configured to receive user data originating from a transmission from a user equipment (UE) to a base station, wherein the base station comprises a radio interface and processing circuitry, the base station’s processing circuitry configured to perform any of the steps of any of the Group B embodiments.

E24. The communication system of the previous embodiment further including the base station.

E25. The communication system of the previous 2 embodiments, further including the UE, wherein the UE is configured to communicate with the base station.

E26. The communication system of the previous 3 embodiments, wherein:

the processing circuitry of the host computer is configured to execute a host application; the UE is configured to execute a client application associated with the host application, thereby providing the user data to be received by the host computer.

E27. A method implemented in a communication system including a host computer, a base station and a user equipment (UE), the method comprising: at the host computer, receiving, from the base station, user data originating from a transmission which the base station has received from the UE, wherein the UE performs any of the steps of any of the Group A embodiments.

E28. The method of the previous embodiment, further comprising at the base station, receiving the user data from the UE.

E29. The method of the previous 2 embodiments, further comprising at the base station, initiating a transmission of the received user data to the host computer.

[0188] Some of the embodiments contemplated herein are described more fully with reference to the accompanying drawings. Other embodiments, however, are contained within the scope of the subject matter disclosed herein. The disclosed subject matter should not be construed as limited to only the embodiments set forth herein; rather, these embodiments are provided by way of example to convey the scope of the subject matter to those skilled in the art.