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Title:
BANDWIDTH PART EXTENSIONS
Document Type and Number:
WIPO Patent Application WO/2020/058562
Kind Code:
A1
Abstract:
Channel characteristics of a radio channel component or beam received by a user equipment from a network apparatus over at least one configured bandwidth part of a radio channel are estimated (S30). Based on the estimated channel characteristics, a required bandwidth is estimated (S32), which is required to estimate, with a predetermined reliability, characteristics of a predetermined signal. A bandwidth part indicator is reported (S34) to the network apparatus, which indicates the estimated required bandwidth for the radio channel component or beam received by the user equipment from the network apparatus. The network apparatus may adapt configured bandwidth parts of the radio channel based on the received bandwidth part indicator.

Inventors:
ZIRWAS WOLFGANG (DE)
ENESCU MIHAI (FI)
DALSGAARD LARS (FI)
Application Number:
FI2018/050680
Publication Date:
March 26, 2020
Filing Date:
September 21, 2018
Export Citation:
Click for automatic bibliography generation   Help
Assignee:
NOKIA TECHNOLOGIES OY (FI)
International Classes:
H04W72/04; H04B7/0408; H04B7/06; H04B17/24; H04B17/309; H04L5/00; H04L25/02; H04W16/10; H04W24/10; H04W28/06; H04B7/024
Domestic Patent References:
WO2016115654A12016-07-28
Foreign References:
US20170126439A12017-05-04
US20180183551A12018-06-28
CN107872891A2018-04-03
Other References:
"Technical Specification Group Radio Access Network; NR; Physical layer procedures for data (Release 15", 3GPP TS 38.214, 29 June 2018 (2018-06-29), XP051454110, Retrieved from the Internet [retrieved on 20190611]
Attorney, Agent or Firm:
NOKIA TECHNOLOGIES OY et al. (FI)
Download PDF:
Claims:
CLAIMS

1. A method for use by a user equipment, the method comprising :

estimating channel characteristics of at least one radio channel component or beam received by the user equipment from at least one network apparatus over at least one configured bandwidth part of a radio channel; based on the estimated channel characteristics, estimating a required bandwidth which is required to estimate, with a predetermined reliability, characteristics of a predetermined signal; and

reporting a bandwidth part indicator to the at least one network apparatus, which indicates the estimated required bandwidth for the at least one radio channel component or beam received by the user equipment from the at least one network apparatus.

2. The method of claim 1, wherein the channel characteristics comprise multi path component parameters.

3. The method of claim 1 or 2, comprising :

estimating characteristics of the predetermined signal received by the user equipment over at least one adapted configured bandwidth part with a bandwidth determined by the bandwidth part indicator;

based on the estimated characteristics, reconstructing a transfer function of the radio channel with a bandwidth larger than that of the adapted configured bandwidth part; and

estimating channel state information of the radio channel based on the reconstructed transfer function and reporting the estimated channel state information to the at least one network apparatus.

4. The method of claim 3, wherein a configured bandwidth part comprises at least two subsets of the overall frequency bandwidth of the configured bandwidth part, wherein a subband bandwidth of the at least two subsets is determined by the bandwidth part indicator for at least two different beams or antenna ports corresponding to the at least two subsets.

5. The method of claim 3,

wherein the estimating comprises:

alternately activating over time

a first adapted configured bandwidth part with a first bandwidth determined by the bandwidth part indicator, wherein the first adapted configured bandwidth part is configured in a lower frequency band of the radio channel, and

a second adapted configured bandwidth part with a second bandwidth determined by the bandwidth part indicator, wherein the second adapted configured bandwidth part is configured in an upper frequency band of the radio channel;

at a first time instance, estimating first characteristics of the

predetermined signal over a first physical resource block of the first adapted configured bandwidth part;

at a second time instance, estimating second characteristics of the predetermined signal over a second physical resource block of the second adapted configured bandwidth part;

at a third time instance, estimating third characteristics of the

predetermined signal over a third physical resource block of the first adapted configured bandwidth part; and

interpolating fourth characteristics of the predetermined signal over the second physical resource block of the first adapted configured bandwidth part by using the first and third characteristics of the predetermined signal, and wherein the reconstructing comprises:

reconstructing the transfer function of the radio channel based on the estimated second characteristics of the predetermined signal and the interpolated fourth characteristics of the predetermined signal.

6. The method of claim 5, wherein by using the first to third physical resource blocks coordinated reference signals for channel state information are received from the at least one network apparatus.

7. A method for use by a network apparatus, the method comprising : configuring bandwidth parts of a radio channel according to a bandwidth part concept in which user equipments are active only in one single bandwidth part at a time;

receiving, from a user equipment, a bandwidth part indicator indicating an estimated required bandwidth for each of at least one radio channel component or beam used by the user equipment for communicating with the network apparatus, wherein the estimated required bandwidth is required to estimate, with a predetermined reliability, characteristics of a predetermined signal; and

adapting the configured bandwidth parts of the radio channel based on the received bandwidth part indicator.

8. The method of claim 7, comprising :

configuring, for a beam or an antenna port, a subset of the overall frequency bandwidth of a configured bandwidth part, wherein a subband bandwidth of the subset is determined by the bandwidth part indicator for the beam.

9. The method of claim 7, comprising :

configuring, in a lower frequency band of the radio channel, a first adapted bandwidth part with a first bandwidth determined by the bandwidth part indicator; and

configuring, in an upper frequency band of the radio channel, a second adapted bandwidth part with a second bandwidth determined by the

bandwidth part indicator;

at a first time instance, transmitting the predetermined signal over a first physical resource block of the first adapted bandwidth part;

at a second time instance, transmitting the predetermined signal over a second physical resource block of the second adapted bandwidth part; and at a third time instance, transmitting the predetermined signal over a third physical resource block of the first adapted bandwidth part.

10. The method of claim 9, wherein by using the first to third physical resource blocks coordinated reference signals for channel state information are transmitted from the network apparatus.

11. The method of any one of claims 1 to 10, wherein

the coordinated reference signals comprise channel state information reference signals, and/or

the bandwidth part indicator is reported using a table relating numbers of physical resource blocks to values, and/or

the characteristics, including the first to third characteristics, comprise channel state information, and/or

the method comprises communicating configuration of bandwidth parts, configuration of a switching pattern defining alternate activation of configured bandwidth parts, configuration of reference signals, and amounts of at least one of a predetermined power, predetermined reliability and predetermined error between the user equipment and the at least one network apparatus, and/or

configuration and amounts are communicated using at least one of dedicated radio resource control signaling, downlink control information and a message including a control element of medium access control.

12. A user equipment comprising at least one processor and at least one memory including computer program code, the at least one memory and the computer program code configured to, with the at least one processor, cause the user equipment at least to perform :

estimating channel characteristics of at least one radio channel component or beam received by the user equipment from at least one network apparatus over at least one configured bandwidth part of a radio channel; based on the estimated channel characteristics, estimating a required bandwidth which is required to estimate, with a predetermined reliability, characteristics of a predetermined signal; and

reporting a bandwidth part indicator to the at least one network apparatus, which indicates the estimated required bandwidth for the at least one radio channel component or beam received by the user equipment from the at least one network apparatus.

13. The user equipment of claim 12, wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the user equipment to further perform :

estimating characteristics of the predetermined signal received by the user equipment over at least one adapted configured bandwidth part with a bandwidth determined by the bandwidth part indicator;

based on the estimated characteristics, reconstructing a transfer function of the radio channel with a bandwidth larger than that of the adapted configured bandwidth part; and

estimating channel state information of the radio channel based on the reconstructed transfer function and reporting the estimated channel state information to the at least one network apparatus.

14. The user equipment of claim 13,

wherein the estimating comprises:

alternately activating over time

a first adapted configured bandwidth part with a first bandwidth determined by the bandwidth part indicator, wherein the first adapted configured bandwidth part is configured in a lower frequency band of the radio channel, and

a second adapted configured bandwidth part with a second bandwidth determined by the bandwidth part indicator, wherein the second adapted configured bandwidth part is configured in an upper frequency band of the radio channel;

at a first time instance, estimating first characteristics of the

predetermined signal over a first physical resource block of the first adapted configured bandwidth part;

at a second time instance, estimating second characteristics of the predetermined signal over a second physical resource block of the second adapted configured bandwidth part; at a third time instance, estimating third characteristics of the

predetermined signal over a third physical resource block of the first adapted configured bandwidth part; and

interpolating fourth characteristics of the predetermined signal over the second physical resource block of the first adapted configured bandwidth part by using the first and third characteristics of the predetermined signal, and wherein the reconstructing comprises:

reconstructing the transfer function of the radio channel based on the estimated second characteristics of the predetermined signal and the interpolated fourth characteristics of the predetermined signal.

15. The user equipment of claim 14, wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the user equipment to further perform :

receiving from the at least one network apparatus coordinated reference signals for channel state information by using the first to third physical resource blocks.

16. A network apparatus comprising at least one processor and at least one memory including computer program code, the at least one memory and the computer program code configured to, with the at least one processor, cause the network apparatus at least to perform:

configuring bandwidth parts of a radio channel according to a bandwidth part concept in which user equipments are active only in one single bandwidth part at a time;

receiving, from a user equipment, a bandwidth part indicator indicating an estimated required bandwidth for each of at least one radio channel component or beam used by the user equipment for communicating with the network apparatus, wherein the estimated required bandwidth is required to estimate, with a predetermined reliability, characteristics of a predetermined signal; and

adapting the configured bandwidth parts of the radio channel based on the received bandwidth part indicator.

17. The network apparatus of claim 16, wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the network apparatus to further perform :

configuring, for a beam or an antenna port, a subset of the overall frequency bandwidth of a configured bandwidth part, wherein a subband bandwidth of the subset is determined by the bandwidth part indicator for the beam.

18. The network apparatus of claim 16, wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the network apparatus to further perform :

configuring, in a lower frequency band of the radio channel, a first adapted bandwidth part with a first bandwidth determined by the bandwidth part indicator; and

configuring, in an upper frequency band of the radio channel, a second adapted bandwidth part with a second bandwidth determined by the

bandwidth part indicator;

at a first time instance, transmitting the predetermined signal over a first physical resource block of the first adapted bandwidth part;

at a second time instance, transmitting the predetermined signal over a second physical resource block of the second adapted bandwidth part; and at a third time instance, transmitting the predetermined signal over a third physical resource block of the first adapted bandwidth part.

19. The network of claim 18, wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the network apparatus to further perform :

transmitting coordinated reference signals for channel state information by using the first to third physical resource blocks.

20. A non-transitory computer-readable storage medium storing a program comprising instructions that when executed by a computer cause the computer to perform : estimating channel characteristics of at least one radio channel component or beam received by the user equipment from at least one network apparatus over at least one configured bandwidth part of a radio channel;

based on the estimated channel characteristics, estimating a required bandwidth which is required to estimate, with a predetermined reliability, characteristics of a predetermined signal; and

reporting a bandwidth part indicator to the at least one network apparatus, which indicates the estimated required bandwidth for the at least one radio channel component or beam received by the user equipment from the at least one network apparatus.

21. A non-transitory computer-readable storage medium storing a program comprising instructions that when executed by a computer cause the computer to perform :

configuring bandwidth parts of a radio channel according to a bandwidth part concept in which user equipments are active only in one single bandwidth part at a time;

receiving, from a user equipment, a bandwidth part indicator indicating an estimated required bandwidth for each of at least one radio channel component or beam used by the user equipment for communicating with the network apparatus, wherein the estimated required bandwidth is required to estimate, with a predetermined reliability, characteristics of a predetermined signal; and

adapting the configured bandwidth parts of the radio channel based on the received bandwidth part indicator.

Description:
BANDWIDTH PART EXTENSIONS

TECHNICAL FIELD

At least some embodiments relate to bandwidth part (BWP) extensions in a communication system.

BACKGROUND

Recently, BWPs have been introduced into a communication system according to New Radio. One main restriction of this newly introduced BWP concept is that UEs will be active only in one single BWP at a time, with the goal to reduce the UE complexity or to save power. At the same time UEs will be able to switch BWPs by DCI messages within short time intervals, i.e., in the ms range.

LIST OF ABBREVIATIONS

BWP bandwidth part

CC channel components

CE control element

CIR channel impulse response h(t,tau)

time-domain representation of the channel

CoMP coordinated multipoint

CQI channel quality indicator

CSI channel state information

CTF channel transfer function

DCI downlink control information

DL downlink

gNB NR base station

IoT internet of things

JT joint transmission

MAC medium access control (protocol layering context)

MPC multipath components

NLOS non-line-of-sight

NR new radio

OFDM orthogonal frequency division multiplexing

RF radio frequency RRC radio resource control

RS reference signal

RSRP reference signal received power

SINR signal to interference and noise ratio

SRS sounding reference signal

TRP transmit receive point

TTI transmission timing interval

PNL power normalization loss

PRB physical resource block

UE user equipment

UL uplink

SUMMARY

At least some embodiments address a problem of how to enhance the BWP framework so that more advanced multi TRP JT CoMP schemes can be supported, for example for efficient estimation of relevant channel components or for close to optimum channel estimation, possibly including the support of channel prediction.

Further, at least some embodiments address a problem of how to minimize scheduling delays, which are so far unavoidable for the BWP concept.

According to at least some embodiments, the above problems are solved by methods, apparatuses and non-transitory computer-readable media as defined in the appended claims.

In particular, according to an example embodiment, a user equipment comprising at least one processor and at least one memory including computer program code is provided, the at least one memory and the computer program code configured to, with the at least one processor, cause the user equipment at least to perform :

estimating channel characteristics of at least one radio channel component or beam received by the user equipment from at least one network apparatus over at least one configured bandwidth part of a radio channel; based on the estimated channel characteristics, estimating a required bandwidth which is required to estimate, with a predetermined reliability, characteristics of a predetermined signal; and

reporting a bandwidth part indicator to the at least one network apparatus, which indicates the estimated required bandwidth for the at least one radio channel component or beam received by the user equipment from the at least one network apparatus.

According to an example embodiment, the channel characteristics comprise multi path component parameters.

According to an example embodiment, the at least one memory and the computer program code are configured to, with the at least one processor, cause the user equipment to further perform :

estimating characteristics of the predetermined signal received by the user equipment over at least one adapted configured bandwidth part with a bandwidth determined by the bandwidth part indicator;

based on the estimated characteristics, reconstructing a transfer function of the radio channel with a bandwidth larger than that of the adapted configured bandwidth part; and

estimating channel state information of the radio channel based on the reconstructed transfer function and reporting the estimated channel state information to the at least one network apparatus.

According to an example embodiment, a configured bandwidth part comprises at least two subsets of the overall frequency bandwidth of the configured bandwidth part, wherein a subband bandwidth of the at least two subsets is determined by the bandwidth part indicator for at least two different beams or antenna ports corresponding to the at least two subsets.

According to an example embodiment,

the estimating comprises:

alternately activating over time a first adapted configured bandwidth part with a first bandwidth determined by the bandwidth part indicator, wherein the first adapted configured bandwidth part is configured in a lower frequency band of the radio channel, and

a second adapted configured bandwidth part with a second bandwidth determined by the bandwidth part indicator, wherein the second adapted configured bandwidth part is configured in an upper frequency band of the radio channel;

at a first time instance, estimating first characteristics of the

predetermined signal over a first physical resource block of the first adapted configured bandwidth part;

at a second time instance, estimating second characteristics of the predetermined signal over a second physical resource block of the second adapted configured bandwidth part;

at a third time instance, estimating third characteristics of the

predetermined signal over a third physical resource block of the first adapted configured bandwidth part; and

interpolating fourth characteristics of the predetermined signal over the second physical resource block of the first adapted configured bandwidth part by using the first and third characteristics of the predetermined signal, and the reconstructing comprises:

reconstructing the transfer function of the radio channel based on the estimated second characteristics of the predetermined signal and the interpolated fourth characteristics of the predetermined signal.

According to an example embodiment, the at least one memory and the computer program code are configured to, with the at least one processor, cause the user equipment to further perform :

receiving from the at least one network apparatus coordinated reference signals for channel state information by using the first to third physical resource blocks.

According to an example embodiment, a network apparatus comprising at least one processor and at least one memory including computer program code is provided, the at least one memory and the computer program code configured to, with the at least one processor, cause the network apparatus at least to perform :

configuring bandwidth parts of a radio channel according to a bandwidth part concept in which user equipments are active only in one single bandwidth part at a time;

receiving, from a user equipment, a bandwidth part indicator indicating an estimated required bandwidth for each of at least one radio channel component or beam used by the user equipment for communicating with the network apparatus, wherein the estimated required bandwidth is required to estimate, with a predetermined reliability, characteristics of a predetermined signal; and

adapting the configured bandwidth parts of the radio channel based on the received bandwidth part indicator.

According to an example embodiment, the at least one memory and the computer program code are configured to, with the at least one processor, cause the network apparatus to further perform :

configuring, for a beam or an antenna port, a subset of the overall frequency bandwidth of a configured bandwidth part, wherein a subband bandwidth of the subset is determined by the bandwidth part indicator for the beam.

According to an example embodiment, the at least one memory and the computer program code are configured to, with the at least one processor, cause the network apparatus to further perform :

configuring, in a lower frequency band of the radio channel, a first adapted bandwidth part with a first bandwidth determined by the bandwidth part indicator; and

configuring, in an upper frequency band of the radio channel, a second adapted bandwidth part with a second bandwidth determined by the

bandwidth part indicator;

at a first time instance, transmitting the predetermined signal over a first physical resource block of the first adapted bandwidth part; at a second time instance, transmitting the predetermined signal over a second physical resource block of the second adapted bandwidth part; and at a third time instance, transmitting the predetermined signal over a third physical resource block of the first adapted bandwidth part.

According to an example embodiment, the at least one memory and the computer program code are configured to, with the at least one processor, cause the network apparatus to further perform :

transmitting coordinated reference signals for channel state information by using the first to third physical resource blocks.

According to an example embodiment, the coordinated reference signals comprise channel state information reference signals.

According to an example embodiment, the bandwidth part indicator is reported using a table relating numbers of physical resource blocks to values.

According to an example embodiment, the characteristics, including the first to third characteristics, comprise channel state information.

According to an example embodiment, the at least one memory and the computer program code are configured to, with the at least one processor, cause the user equipment to further perform receiving configuration of bandwidth parts, configuration of a switching pattern defining alternate activation of configured bandwidth parts, configuration of reference signals, and amounts of at least one of a predetermined power, predetermined reliability and predetermined error from the at least one network apparatus.

According to an example embodiment, the at least one memory and the computer program code are configured to, with the at least one processor, cause the network apparatus to further perform transmitting configuration of bandwidth parts, configuration of a switching pattern defining alternate activation of configured bandwidth parts, configuration of reference signals, and amounts of at least one of a predetermined power, predetermined reliability and predetermined error to the user equipment.

According to an example embodiment, configuration and amounts are communicated using at least one of dedicated radio resource control signaling, downlink control information and a message including a control element of medium access control.

In the following embodiments will be described with reference to the

accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 shows a diagram illustrating varying channel characteristics and their impact on a BWP bandwidth size.

Fig. 2 shows a diagram illustrating a relation of BWP indicator and channel characteristics.

Fig. 3 shows a flowchart illustrating a process 1 according to an example embodiment.

Fig. 4 shows a flowchart illustrating a process 2 according to an example embodiment.

Fig. 5 shows a diagram illustrating an interpolation scheme.

Fig. 6 shows a diagram illustrating a simultaneous estimation for multiple beams on different frequency subbands or BWPs.

Fig. 7 shows a schematic block diagram illustrating a configuration of control units in which examples of embodiments are implementable.

DESCRIPTION OF THE EMBODIMENTS The BWP concept supports, for example, reduced UE bandwidth capability, reduced UE energy consumption, FDM of different numerologies, non- contiguous spectrum, and forward compatibility.

According to the BWP concept, only one BWP is active at a time, thereby limiting, for example, the channel estimation quality.

Further, according to the BWP concept, fast switching based on DCI messages between BWPs is possible. Fast means in this case that per TTI BWP switching is possible at a minimum switching time, which mainly is limited by RF component characteristics. For example, the switching time is in the range few OFDM symbols, but this reflects only the RF components.

However, the BWP switching on the RF side is only one part of the relevant timing, while scheduling of UEs from one BWP to a potential other BWP currently takes a much longer time. This is due to the need for new channel estimation, reporting of CSI and CQI information as well as scheduling for the new BWP.

An issue of interest is as illustrated in Fig. 1, i.e., the different characteristics of radio channels and their impact to the BWP bandwidth. For example, the radio channel 100 depicted in Fig. 1 is a slowly over frequency varying channel as it is typical for indoor channels, outdoor channels in urban micro scenarios or, e.g., for outdoor urban macro UEs close to a base station.

Quite different is the radio channel 200 depicted in Fig. 1, which is a typical frequency selective NLOS urban macro radio channel. For the BWP it leads to the issue that for the radio channel 100, basic channel characteristics at one BWP might be very different from that at a potential other BWP frequency, for example with respect to an Rx-power (RSRP measurement). Otherwise, the radio channel 200 will have at any possible BWP quite similar channel characteristics. According to at least some embodiments, specific BWP switching modes are defined and parameters like the bandwidth of a certain BWP is adapted based on a predetermined reliability of predetermined signal measurements (e.g. RSRP measurements) for a certain BWP bandwidth. For the reporting of such reliability, a BWP indicator is being proposed, which indicates a required bandwidth for a predetermined reliability of, e.g., 90%.

The corresponding BWP indicator IBWP can be applied to different

applications, like for example setting UE specific SRS bandwidth so that in the UL all relevant beams and their relative power can be estimated with a predetermined reliability, in case the BWP bandwidth is at least as large as proposed by the BWP indicator IBWP.

A way how the BWP indicator IBWP is calculated is illustrated in Fig. 2 showing two different CIRs, one with a relatively distributed allocation of MPCs and the lower one, where the MPCs all have quite similar delay.

Using a profiling concept, one can do a parameter estimation for the relevant multi path components even for a relatively low measurement bandwidth. For the calculation of the BWP indicator the estimation quality for MPC parameters can be relaxed as for this purpose the general structure of the CIR is sufficient. Based on this general structure, the required bandwidth to capture a certain RSRP power with a predetermined reliability can be estimated.

After having calculated the BWP indicator IBWP, a UE reports values of the IBWP per relevant radio channel component or per beam to a gNB with which the UE communicates. According to an implementation example, the reporting is performed using a table so that for example an IBWP value of Ί' indicates a bandwidth of 6 PRBs, '2' indicates 12 PRBs, '3' indicates 24 PRBs, and '4' indicates a full bandwidth over all PRBs.

Fig. 3 shows a flowchart illustrating a process 1 according to an example embodiment. Process 1 shown in Fig. 3 may be performed by a user equipment (e.g. the above-mentioned UE) of a communication system applying the BWP concept.

In step S30, channel characteristics of at least one radio channel component or beam received by the user equipment from at least one network apparatus of a communication system (e.g. from a base station such as the above- mentioned gNB) over at least one configured bandwidth part (e.g. the above- mentioned BWP) of a radio channel are estimated. The channel characteristics may comprise multi path component parameters.

In step S32, based on the estimated channel characteristics, a required bandwidth is estimated, which is required to estimate, with a predetermined reliability, characteristics of a predetermined signal.

In step S34, a bandwidth part indicator (e.g. the above-mentioned BWPI) is reported to the at least one network apparatus, which indicates the estimated required bandwidth for the at least one radio channel component or beam received by the user equipment from the at least one network apparatus.

Fig. 4 shows a flowchart illustrating a process 2 according to an example embodiment.

Process 2 shown in Fig. 4 may be performed by a network apparatus, e.g. a base station such as the above-mentioned gNB, of the communication system applying the BWP concept.

In step S40, bandwidth parts of a radio channel are configured according to a bandwidth part concept (e.g. the above-mentioned BWP concept) in which user equipments are active only in one single bandwidth part at a time.

In step S42, a bandwidth part indicator (e.g. the above-mentioned BWPI) is received from a user equipment (e.g. the above-mentioned UE), which indicates an estimated required bandwidth for each of at least one radio channel component or beam used by the user equipment for communicating with the network apparatus, wherein the estimated required bandwidth is required to estimate, with a predetermined reliability, characteristics of a predetermined signal.

In step S44, the configured bandwidth parts of the radio channel are adapted based on the received bandwidth part indicator.

As mentioned above, the estimation accuracy for the multi path component parameters for the purpose of finding the proper BWP indicator value is relatively low. However, it may be desired to estimate or predict CSI information for the full bandwidth of the radio channel based on a CSI estimation for the limited BWP bandwidth. This is in principle possible by applying super resolution techniques like the already mentioned concept of CIR profiling, which is basically a parameter estimation of the MPC parameters plus a reconstruction of the full wideband channel transfer function (CTF) based on these estimated MPC parameters. This reconstruction is now obviously much more sensitive to any parameter estimation error.

According to an example embodiment, the bandwidth part concept is extended to the application of frequency domain channel prediction. In other words, per radio channel a minimum bandwidth is estimated, which allows for an accurate estimation of a CTF up to a certain overall bandwidth.

A corresponding normalized mean square error (NMSE) for the CSI estimation and the possible bandwidths may be predefined or standardized or set by corresponding RRC messages between the network apparatus and the user equipment.

According to an example embodiment, referring to the description of Fig. 3 above, characteristics of the predetermined signal received by the user equipment over at least one adapted configured bandwidth part with a bandwidth determined by the bandwidth part indicator are estimated. Based on the estimated characteristics, a transfer function (e.g. the above- mentioned CTF) of the radio channel with a bandwidth larger than that of the adapted configured bandwidth part is reconstructed. Channel state information of the radio channel is estimated based on the reconstructed transfer function, and the estimated channel state information is reported to the at least one network apparatus.

According to an example embodiment, the channel predictability is improved despite the limited overall BWP bandwidth according to the illustration in Fig.

5. The upper part of Fig. 5 shows two different radio channels, where for the CTF 300 the BWP indicator IBWP is large, while for the CTF 400 a low value of the BWP indicator IBWP indicates that a reliable RSRP estimation is possible with a small bandwidth. The BWP indicator IBWP can be used for example to adapt the frequency bandwidth of the upper and lower BWP, used for interpolation of the radio channel as shown in the lower part of Fig. 5 and described below.

In that case, a suitably adapted BWP switching pattern is adopted for the CSI estimation process, where a lower and an upper BWP are configured using e.g. an RRC message, and then switching is performed in a predefined manner between the lower and the upper bandwidth parts. According to an

implementation example, in the first OFDM symbol or PRB the lower BWP is activated, in the second PRB the upper BWP is activated, and in the third PRB again the lower BWP is activated. This switching provides very good

interpolation opportunities in frequency as well as time domain. By using the lowest and highest possible BWP frequencies the 'effective' bandwidth for the super resolution parameter estimation is maximized. This enables best possible interpolation performance. By switching to the lowest BWP in the first and in the third PRB it is possible to interpolate in time domain for the second PRB so that the interpolated lowest BWP CSI and the highest BWP CSI can be combined into one single combined CTF for a single time instance.

As described above, characteristics of the predetermined signal received by the user equipment over at least one adapted configured bandwidth part with a bandwidth determined by the bandwidth part indicator are estimated.

According to an example embodiment, in this estimation, a first adapted configured bandwidth part with a first bandwidth determined by the bandwidth part indicator, wherein the first adapted configured bandwidth part is configured in a lower frequency band of the radio channel, and a second adapted configured bandwidth part with a second bandwidth determined by the bandwidth part indicator, wherein the second adapted configured bandwidth part is configured in an upper frequency band of the radio channel are alternately activated over time.

At a first time instance, first characteristics of the predetermined signal over a first physical resource block of the first adapted configured bandwidth part are estimated. At a second time instance, second characteristics of the

predetermined signal over a second physical resource block of the second adapted configured bandwidth part are estimated. At a third time instance, third characteristics of the predetermined signal over a third physical resource block of the first adapted configured bandwidth part are estimated.

Fourth characteristics of the predetermined signal over the second physical resource block of the first adapted configured bandwidth part are interpolated by using the first and third characteristics of the predetermined signal. The transfer function of the radio channel is reconstructed based on the estimated second characteristics of the predetermined signal and the interpolated fourth characteristics of the predetermined signal.

According to an example implementation, by using the first to third physical resource blocks, coordinated reference signals for channel state information are received from the at least one network apparatus.

Referring to the description of Fig. 4, according to an example embodiment, at the network apparatus site, in a lower frequency band of the radio channel, a first adapted bandwidth part with a first bandwidth determined by the bandwidth part indicator is configured. Further, in an upper frequency band of the radio channel, a second adapted bandwidth part with a second bandwidth determined by the bandwidth part indicator is configured. At a first time instance, the predetermined signal is transmitted over a first physical resource block of the first adapted bandwidth part, at a second time instance, the predetermined signal is transmitted over a second physical resource block of the second adapted bandwidth part, and at a third time instance, the predetermined signal is transmitted over a third physical resource block of the first adapted bandwidth part.

According to an example implementation, after some e.g. predefined time this pattern is repeated so that a channel tracking and periodic reporting is possible. In addition, this example implementation may be combined with channel prediction.

Generally, the NR BWP framework may enable such fast BWP switching by according DCI messages. Nonetheless, according to an example

implementation, such BWP switching patterns are predefined. Then, UE and gNBs are prepared for the switching, transmission of according CSI RSs as well as the CSI estimation of the according BWPs. The same is true, e.g., for the interpolation and parameter estimation processes at the UE.

By predefining the patterns e.g. using specific RRC messages corresponding DCI messages can be saved and replaced by one single MAC CE message.

According to an example implementation, for the above-described frequency interpolation scheme the BWP indicator IBWP is used with a slightly different estimation of the BWP bandwidth, because the interpolation estimation quality depends on the bandwidth of the higher and the lower BWP, the frequency distance between the upper and lower BWP as well as on the channel characteristics as mentioned already above, like compact or distributed allocation of MPCs, SINR, etc.

According to an example embodiment, for the usage of the BWP indicator, a multi TRP mode like inter site JT CoMP is considered, where the BWPs of the beams of multiple cells and sites are switched in a harmonized way, for example with the goal to support multi TRP accurate CSI estimation for all relevant channel components with moderate - or even minimum possible - overhead. This is illustrated in Fig. 6, where UEs use a large BWP bandwidth and beams from cells or antenna ports use certain subsets of the overall frequency bandwidth so that at one time instance for example simultaneously three beams can be measured per UE and each UE can estimate the RSRP power for these three beams. For that purpose, the UE - receiving over the large bandwidth part bandwidth - will do separate estimations for the smaller bandwidth subsets in parallel and independently between the subsets. In case the subset bandwidth per beam has been chosen according to the bandwidth part indicator the estimation quality will be similar to the case when doing an estimation over the full bandwidth for each beam sequentially. That way, a significant overhead saving for example with respect to CSI reference signals will be possible.

For this application of the BWP indicator the BWP concept may be considered. Alternatively, a single wideband BWP with certain subbands can be adopted. The BWP indicator IBWP is used as the gNBs have to decide on the minimum beam width needed for each beam to allow all UEs to do reliable RSRP measurements.

According to an example implementation, a configured bandwidth part comprises at least two subsets of the overall frequency bandwidth of the configured bandwidth part, wherein a subband bandwidth of the at least two subsets is determined by the bandwidth part indicator for at least two different beams corresponding to the at least two subsets.

According to at least some embodiments, support of channel estimation and prediction over a frequency-band of maximum size despite a relatively small BWP configuration is provided. This enables trade-offs between the Fisher information - which would be optimal for the maximum possible estimation bandwidth - and a low BWP bandwidth, with accordingly lower power consumption and lower resource usage. According to at least some embodiments, required bandwidth for estimation of relevant channel components (CC) or beams is minimized. For example, for a multi TRP cooperation area over nine cells, there may be up to 288 possible beams and in a first step the relevant beams have to be identified per UE. One option to estimate the relevant channel components is to rely on channel reciprocity and to estimate the UL power for all beams based on SRS

transmission. To minimize the UE Tx-power and to enable RSRP

measurements for multiple UEs, with the above-described RSRP reliability measure, the BWPs size per UE can be suitably adapted to the channel characteristics.

At least some embodiments support fast scheduling by inter band CSI interpolation or prediction. For that purpose, most upper and lower BWPs are combined for the best frequency interpolation performance.

According to an example implementation, BWPs are configured, e.g. by a network apparatus of a communication system, for a single or for upper and lower frequency bands. The size of the BWP(s) is adapted e.g. by the network apparatus so that it fits to the channel characteristic of the intended channel components.

According to an example implementation, UEs of the communication system report bandwidth part indicators IBWP for their relevant channel components.

According to an example implementation adopting the above-described interpolation mode, the network apparatus, e.g. gNB, switches upper and lower BWPs in a fast and predefined manner, coordinated over multiple sites and cells as shown in Fig. 5 and transmits corresponding predefined CSI information (also referred to here as predetermined signal) per beam.

In the interpolation mode, the UEs estimate CSI per BWP and interpolate between two lower BWPs over time so that CSI for upper and lower BWP can be combined, despite the fact that at any time instance there is only one BWP active. The UEs report estimated and interpolated CSI to the gNB, which may use it, e.g., for MU MIMO, JT CoMP, NL precoding or other advanced transmission schemes. In particular, the gNB may use the interpolated CSI to estimate CQI and other values needed for flexible scheduling in any other frequency subband or BWP.

According to at least some embodiments, the bandwidth part indicator IBWP enables a fine granular adaptation of the gNB Tx- and UE Rx bandwidth to the channel characteristics as well as to certain load conditions or other relevant criteria. This can be used to improve energy efficiency for measurements like RSRP per beam or CSI estimations, with or without additional interpolation over frequency and/or time.

According to at least some embodiments, the BWP indicator provides a measure to what extent a certain RSRP measurement will be valid also for other BWPs. Assuming suitable channel conditions one RSRP measurement may be then used for all possible BWPs, while still guaranteeing a certain estimation accuracy.

Particularly in case of CSI interpolation, overhead for CSI RSs and for CSI reporting can be saved, e.g. by limited estimation and reporting to the BWP(s) plus reconstruction of the full wideband CSI by super resolution techniques at the gNB.

Similarly, multiple CSI for multiple beams can be multiplexed in multiple parallel frequency subbands or BWPs.

The proposed lower and upper BWP switching pattern maximizes the Fisher information for channel estimation due to maximum 'effective' bandwidth, which results in significantly improved CSI estimation quality. This combined estimation for a lower and upper BWP is especially well suited for the parameter estimation concepts like the CIR profiling as a parameter mismatch in one BWP will generally lead to a strong CSI error in the other BWP. It is noted that for certain CIR constellations an additional BWP in the middle of the overall frequency band may be useful. According to an example

implementation, this is part of a further enhanced BWP indicator reporting.

The predefined BWP switching enables an accurate interpolation between BWPs despite there is only a single BWP per time slot active. Using a predefined switching pattern causes a minimum extra control overhead.

Two predefined estimation instances allow to estimate the CSI evolution over time and accordingly the MPC evolution. Based on this, an accurate prediction of the MPC parameters becomes possible.

The CSI interpolation in frequency direction enables fast switching into other BWPs as it avoids the otherwise needed extra steps of CSI estimation and reporting as well as scheduling in the newly activated BWP. This reduces the BWP switching time to that of the RF part switching time, which can be very low.

According to an example implementation, the BWP indicator is used for DL CSI RSs as well as for UL SRS signals due to the channel reciprocity.

Now reference is made to Fig. 7 illustrating a simplified block diagram of various electronic devices that are suitable for use in practicing at least some embodiments.

Fig. 7 shows a control unit 10 comprising processing resources (e.g.

processing circuitry) 11, memory resources (e.g. memory circuitry) 12, and interfaces (e.g. interface circuitry) 13, which are coupled via a link 14.

According to an example embodiment, the control unit 10 executes process 1 shown in Fig. 3. According to an example embodiment, the control unit 10 is part of and/or is used by a user equipment of a communication system applying the BWP concept. The memory resources 12 may store a program that is executed by the processing resources 11. The interfaces 13 may comprise a suitable radio frequency (RF) transceiver coupled to one or more antennas for bidirectional wireless communications over one or more wireless links 33 with a control unit

20. The transceiver includes both transmitter and receiver, and inherent in each is a modulator/demodulator commonly known as a modem.

In general, various embodiments of the user equipment can include, but are not limited to, mobile stations, cellular telephones, personal digital assistants (PDAs) having wireless communication capabilities, portable computers having wireless communication capabilities, image capture devices such as digital cameras having wireless communication capabilities, gaming devices having wireless communication capabilities, music storage and playback appliances having wireless communication capabilities, Internet appliances permitting wireless Internet access and browsing, as well as portable units or terminals that incorporate combinations of such functions.

The control unit 20 comprises processing resources (e.g. processing circuitry)

21, memory resources (e.g. memory circuitry) 22, and interfaces (e.g.

interface circuitry) 23, which are coupled via a link 24.

According to an example embodiment, the control unit 20 executes process 2 shown in Fig. 4. According to an example embodiment, the control unit 20 is part of and/or is used by a network apparatus of the communication system applying the BWP concept.

The memory resources 22 may store a program that is executed by the processing resources 21. The interfaces 23 may comprise a suitable radio frequency (RF) transceiver coupled to one or more antennas for bidirectional wireless communications over the one or more wireless links 33 with the control unit 10. The transceiver includes both transmitter and receiver, and inherent in each is a modulator/demodulator commonly known as a modem. The terms "connected," "coupled," or any variant thereof, mean any

connection or coupling, either direct or indirect, between two or more elements, and may encompass the presence of one or more intermediate elements between two elements that are "connected" or "coupled" together. The coupling or connection between the elements can be physical, logical, or a combination thereof. As employed herein two elements may be considered to be "connected" or "coupled" together by the use of one or more wires, cables and printed electrical connections, as well as by the use of electromagnetic energy, such as electromagnetic energy having wavelengths in the radio frequency region, the microwave region and the optical (both visible and invisible) region, as non-limiting examples.

The programs stored in the memory resources 12, 22 are assumed to include program instructions that, when executed by the associated processing resources 11, 21, enable the electronic device to operate in accordance with at least some embodiments and example implementations, as detailed above. Inherent in the processing resources 11, 21 is a clock to enable synchronism among the various apparatus for transmissions and receptions within the appropriate time intervals and slots required, as the scheduling grants and the granted resources/subframes are time dependent.

In general, example embodiments may be implemented by computer software stored in the memory resources 12, 22 and executable by the processing resources 11, 21, or by hardware, or by a combination of software and/or firmware and hardware in any or all of the devices shown.

The memory resources 12, 22 may be of any type suitable to the local technical environment and may be implemented using any suitable data storage technology, such as semiconductor based memory devices, magnetic memory devices and systems, optical memory devices and systems, fixed memory and removable memory. The processing resources 11, 21 may be of any type suitable to the local technical environment, and may include one or more of general purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs) and processors based on a multi core processor architecture, as non-limiting examples.

Further, as used in this application, the term "circuitry" refers to one or more or all of the following :

(a) hardware-only circuit implementations (such as implementations in only analog and/or digital circuitry) and

(b) to combinations of circuits and software (and/or firmware), such as (as applicable) : (i) to a combination of processor(s) or (ii) to portions of

processor(s)/software (including digital signal processor(s)), software, and memory(ies) that work together to cause an apparatus, such as a mobile phone or server, to perform various functions) and

(c) to circuits, such as a microprocessor(s) or a portion of a microprocessor(s), that require software or firmware for operation, even if the software or firmware is not physically present.

This definition of "circuitry" applies to all uses of this term in this application, including in any claims. As a further example, as used in this application, the term "circuitry" would also cover an implementation of merely a processor (or multiple processors) or portion of a processor and its (or their) accompanying software and/or firmware. The term "circuitry" would also cover, for example and if applicable to the particular claim element, a baseband integrated circuit or applications processor integrated circuit for a mobile phone or a similar integrated circuit in server, a cellular network device, or other network device.

According to an example embodiment, a user equipment is provided, which comprises means for estimating channel characteristics of at least one radio channel component or beam received by the user equipment from at least one network apparatus over at least one configured bandwidth part of a radio channel, means for, based on the estimated channel characteristics,

estimating a required bandwidth which is required to estimate, with a predetermined reliability, characteristics of a predetermined signal, and means for reporting a bandwidth part indicator to the at least one network apparatus, which indicates the estimated required bandwidth for the at least one radio channel component or beam received by the user equipment from the at least one network apparatus.

According to an example embodiment, the channel characteristics comprise multi path component parameters.

According to an example embodiment, the user equipment further comprises means for estimating characteristics of the predetermined signal received by the user equipment over at least one adapted configured bandwidth part with a bandwidth determined by the bandwidth part indicator, means for, based on the estimated characteristics, reconstructing a transfer function of the radio channel with a bandwidth larger than that of the adapted configured

bandwidth part, and means for estimating channel state information of the radio channel based on the reconstructed transfer function and reporting the estimated channel state information to the at least one network apparatus.

According to an example embodiment, a configured bandwidth part comprises at least two subsets of the overall frequency bandwidth of the configured bandwidth part, wherein a subband bandwidth of the at least two subsets is determined by the bandwidth part indicator for at least two different beams or antenna ports corresponding to the at least two subsets.

According to an example embodiment, the means for estimating comprises means for alternately activating over time, a first adapted configured bandwidth part with a first bandwidth determined by the bandwidth part indicator, wherein the first adapted configured bandwidth part is configured in a lower frequency band of the radio channel, and a second adapted configured bandwidth part with a second bandwidth determined by the bandwidth part indicator, wherein the second adapted configured bandwidth part is configured in an upper frequency band of the radio channel, means for, at a first time instance, estimating first characteristics of the predetermined signal over a first physical resource block of the first adapted configured bandwidth part, at a second time instance, estimating second characteristics of the

predetermined signal over a second physical resource block of the second adapted configured bandwidth part, at a third time instance, estimating third characteristics of the predetermined signal over a third physical resource block of the first adapted configured bandwidth part; and interpolating fourth characteristics of the predetermined signal over the second physical resource block of the first adapted configured bandwidth part by using the first and third characteristics of the predetermined signal, and the means for

reconstructing comprises means for reconstructing the transfer function of the radio channel based on the estimated second characteristics of the

predetermined signal and the interpolated fourth characteristics of the predetermined signal.

According to an example embodiment, the user equipment comprises means for receiving coordinated reference signals for channel state information from the at least one network apparatus by using the first to third physical resource blocks.

According to an example embodiment, the user equipment comprises means for executing process 1 shown in Fig. 3.

According to an example embodiment, the above-described means of the user equipment are implemented by the processing resources 11, the memory resources 12 and the interfaces 13 of the control unit 10.

According to an example embodiment, a network apparatus is provided, which comprises means for configuring bandwidth parts of a radio channel according to a bandwidth part concept in which user equipments are active only in one single bandwidth part at a time, means for receiving, from a user equipment, a bandwidth part indicator indicating an estimated required bandwidth for each of at least one radio channel component or beam used by the user equipment for communicating with the network apparatus, wherein the estimated required bandwidth is required to estimate, with a predetermined reliability, characteristics of a predetermined signal, and means for adapting the configured bandwidth parts of the radio channel based on the received bandwidth part indicator. According to an example embodiment, the network apparatus further comprises means for configuring, for a beam or an antenna port, a subset of the overall frequency bandwidth of a configured bandwidth part, wherein a subband bandwidth of the subset is determined by the bandwidth part indicator for the beam.

According to an example embodiment, the network apparatus further comprises means for configuring, in a lower frequency band of the radio channel, a first adapted bandwidth part with a first bandwidth determined by the bandwidth part indicator, and configuring, in an upper frequency band of the radio channel, a second adapted bandwidth part with a second bandwidth determined by the bandwidth part indicator, and means for, at a first time instance, transmitting the predetermined signal over a first physical resource block of the first adapted bandwidth part, at a second time instance,

transmitting the predetermined signal over a second physical resource block of the second adapted bandwidth part, and at a third time instance, transmitting the predetermined signal over a third physical resource block of the first adapted bandwidth part.

According to an example embodiment, the network apparatus further comprises means for transmitting coordinated reference signals for channel state information by using the first to third physical resource blocks.

According to an example embodiment, the coordinated reference signals comprise channel state information reference signals.

According to an example embodiment, the bandwidth part indicator is reported using a table relating numbers of physical resource blocks to values.

According to an example embodiment, the characteristics, including the first to third characteristics, comprise channel state information. According to an example embodiment, the user equipment further comprises means for receiving configuration of bandwidth parts, configuration of a switching pattern defining alternate activation of configured bandwidth parts, configuration of reference signals, and amounts of at least one of a

predetermined power, predetermined reliability and predetermined error from the at least one network apparatus.

According to an example embodiment, the network apparatus further comprises means for transmitting configuration of bandwidth parts,

configuration of a switching pattern defining alternate activation of configured bandwidth parts, configuration of reference signals, and amounts of at least one of a predetermined power, predetermined reliability and predetermined error to the user equipment.

According to an example embodiment, configuration and amounts are communicated using at least one of dedicated radio resource control signaling, downlink control information and a message including a control element of medium access control.

According to an example embodiment, channel characteristics of a radio channel component or beam received by a user equipment from a network apparatus over at least one configured bandwidth part of a radio channel are estimated. Based on the estimated channel characteristics, a required bandwidth is estimated, which is required to estimate, with a predetermined reliability, characteristics of a predetermined signal. A bandwidth part indicator is reported to the network apparatus, which indicates the estimated required bandwidth for the radio channel component or beam received by the user equipment from the network apparatus. The network apparatus may adapt configured bandwidth parts of the radio channel based on the received bandwidth part indicator.

It is to be understood that the above description is illustrative and is not to be construed as limiting the disclosure. Various modifications and applications may occur to those skilled in the art without departing from the true spirit and scope of the disclosure as defined by the appended claims.