FIELD

The present disclosure relates to wireless communications, and in particular, to generation of a high rate amplitude shift keying (ASK) signal.

INTRODUCTION

The Internet of Things (IoT) is expected to increase the number of connected devices significantly. A vast majority of these devices may operate in unlicensed bands, in particular the 2.4 GHz Industrial Scientific and Medical (ISM) band. There is also increased demand for using the unlicensed bands for services that traditionally have been supported in licensed bands. As an example of the latter, the Third Generation Partnership Project (3 GPP) that traditionally develops specifications only for licensed bands have now also developed versions of Long Term Evolution (LTE) which will operate in the 5 GHz unlicensed band.

A large number of these IoT devices are expected to be powered by coin-cell batteries, which means that energy consumption is of importance. In the future, these devices may be able to harvest their energy themselves, potentially further increasing the importance of low energy consumption.

For these kinds of applications, the supported data rates are low, both concerning peak data rates and aggregated data rate during an average day, for example. This means that a major part of the power is not consumed when the IoT device is transmitting or receiving data, but rather when the device is listening to determine whether there might be a transmission for which it is the intended receiver.

The fact that such a large part of the total energy consumption is due to listening for a potential transmission, only to find that the transmission is not there, has motived the development of so-called wake-up receivers (WUR). A WUR is a device which has extremely low power consumption and that is to wake up the main transceiver. So, an IoT device with a WUR will not need to turn on the main receiver to scan for a potential packet, but will instead turn on the WUR. If there is data for the IoT device, a wake-up signature or signal (WUS) will be sent to the WUR. When the WUR has decoded this WUS, and determined that there is data present, the WUR will then wake up the main receiver and transmitter, and a communication link can be established. A commonly used modulation for the wake-up signal (WUS), i.e., the signal sent to the WUR, is on-off keying (OOK). OOK is a binary modulation, where a logical one represents sending a signal (ON), whereas a logical zero represents not sending a signal (OFF). OOK may be considered a special case of amplitude shift keying (ASK)

There are currently activities ongoing in the Institute of Electrical and Electronics Engineer (IEEE) 802.11 standards task group (TG), called IEEE 802.11ba, to standardize the physical (PHY) layer and medium access control (MAC) layer for a Wake-Up Radio to be used as a companion radio to the 802.11 primary communications radio (PCR), with the purpose of significantly reducing power consumption of the PCR. Similar activities have also started within 3 GPP with a similar purpose.

However, the support of WURs by one or more communication standards come with some challenges. A first challenge is that the WUS typically is sent in-band, i.e., it is sent in the same channel that otherwise could have been used for sending data. This means that the supported data rate is reduced and spectrum efficient means for sending the WUS concurrently with data may be of importance. In 802.1 lba, this is not done, but instead a WUS is sent instead of data. Since most existing communication systems are based on orthogonal frequency division multiplexing (OFDM), there may be a straight-forward way to multiplex the WUS with data using orthogonal frequency division multiple access (OFDMA), provided the symbol rate of the OOK can be matched to the OFDM symbol rate, as illustrated in FIG. 1 where FIG. 1 shows an inverse fast Fourier transform (IFFT) 2, followed by a cyclic prefix 4 for multiplexing a WUS with information data, The WUS is allocated to a suitable number of sub carriers and to represent ON (some random) data is sent on the sub-carriers and to represent OFF no data is sent. However, this puts restrictions on the symbol rate, which may be particularly limiting when the fast Fourier transform (FFT) size is large and thus the OFDM symbol duration is long.

A desirable feature obtained by generating the WUS is that the WUS by design will be orthogonal to the data, which means that the intended receivers of the data signal may not be affected.

Generating the WUS means that a relatively large number of OFDM symbols are needed to generate a WUS, typically 50 -100 symbols in a WUS in order to obtain acceptable receiver performance.

On the other hand, if the WUS has a much higher symbol rate than the OFDM symbol rate used for data, the orthogonality will be lost and the WUS may cause significant inter carrier interference (ICI) for the data sub-carriers. SUMMARY

Some embodiments include methods, network nodes and wireless devices configured to generate wake-up signals (WUS) at a high symbol rate which can be multiplexed with OFDM data while substantially reducing detrimental degradation to the data signal compared to known methods.

Some embodiments advantageously provide methods, network nodes and wireless device for generation of a high rate amplitude shift keying signal.

Some embodiments include generating the WUS at the desired symbol rate, which is higher than the OFDM symbol rate, and then optimizing the waveform such that the leakage into the adjacent bands is at a level that only gives a negligible degradation of the data transmission compared to known methods.

According to another aspect, a network node is configured to communicate with a wireless device, WD. The network node includes processing circuitry configured to: determine a first wake up signal, WUS, the first WUS being configured to indicate when the network node has data intended for the WD, the first WUS having first information being embedded in an amplitude of the WUS. The processing circuitry is further configured to modify the first WUS to produce a second WUS, the second WUS having less energy leakage into at least one neighboring band of the first WUS than the first WUS. The processing circuitry is further configured to multiplex information data with the second WUS to produce a multiplexed signal, the information data being carried by subcarriers in the neighboring band of the first WUS. The network node also includes a radio interface configured to send the multiplexed signal to the WD.

According to this aspect, in some embodiments, the modifying includes determining an optimization of an objective function that is based at least in part on the first WUS. In some embodiments, the objective function includes a matrix having columns that correspond to subcarriers carrying the information data and the second WUS. In some embodiments, at least one matrix column further corresponds to at least one subcarrier of at least one neighboring band. In some embodiments, the modifying includes modulating the information data, and frequency shifting the modulated data so that frequency content of the modulated data falls within a bandwidth not used for sending other data.

According to yet another aspect, a method implemented in a network node includes determining a first wake up signal, WUS, the first WUS being configured to indicate when the network node has data intended for the WD, the first WUS having first information being embedded in an amplitude of the WUS. The method further includes modifying the first WUS to produce a second WUS, the second WUS having less energy leakage into at least one neighboring band of the first WUS than the first WUS. The method further includes multiplexing information data with the second WUS to produce a multiplexed signal, the information data being carried by subcarriers in the neighboring band of the first WUS, and sending the multiplexed signal to the WD.

According to this aspect, in some embodiments, the modifying includes determining an optimization of an objective function that is based at least in part on the first WUS. In some embodiments, the objective function includes a matrix having columns that correspond to subcarriers carrying the information data and the second WUS. In some embodiments, at least one matrix column further corresponds to at least one subcarrier of at least one neighboring band. In some embodiments, the modifying includes modulating the information data, and frequency shifting the modulated data so that frequency content of the modulated data falls within a bandwidth not used for sending other data.

According to another aspect, a WD is configured to communicate with a network node. The WD includes processing circuitry configured to: detect, using an envelope detector, an envelope of a wake up signal, WUS, received by a first receiver to determine a power of the WUS, compare the determined power to a first threshold, and if the determined power falls below the first threshold, using a second receiver to detect a phase of the WUS.

According to this aspect, in some embodiments, if the power of the received WUS is less than a second threshold lower than the first threshold, the WD ignores the WUS and enters a wake state. In some embodiments, the second receiver is a principal communication receiver responsive to a wakeup signal from the first receiver. In some embodiments, the processing circuitry is further configured to first detect a presence of the WUS, followed by determining whether the WUS is intended for the WD.

According to yet another aspect, a method implemented in a wireless device, WD, includes detecting, using an envelope detector, an envelope of a wake up signal, WUS, received by a first receiver to determine a power of the WUS, comparing the determined power to a first threshold, and if the determined power falls below the first threshold, using a second receiver to detect a phase of the WUS.

According to this aspect, in some embodiments, if the power of the received WUS is less than a second threshold lower than the first threshold, the WD ignores the WUS and enters a wake state. In some embodiments, the second receiver is a principal communication receiver responsive to a wakeup signal from the first receiver. In some embodiments, the method further includes first detecting a presence of the WUS, followed by determining whether the WUS is intended for the WD.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete understanding of the present embodiments, and the attendant advantages and features thereof, will be more readily understood by reference to the following detailed description when considered in conjunction with the accompanying drawings wherein:

FIG. 1 is a block diagram showing an input of a WUS and information data into an inverse fast Fourier transform (IFFT);

FIG. 2 is a schematic diagram of an exemplary network architecture illustrating a communication system connected via an intermediate network to a host computer according to the principles in the present disclosure;

FIG. 3 is a block diagram of a host computer communicating via a network node with a wireless device over an at least partially wireless connection according to some embodiments of the present disclosure;

FIG. 4 is a flowchart illustrating exemplary methods implemented in a communication system including a host computer, a network node and a wireless device for executing a client application at a wireless device according to some embodiments of the present disclosure;

FIG. 5 is a flowchart illustrating exemplary methods implemented in a communication system including a host computer, a network node and a wireless device for receiving user data at a wireless device according to some embodiments of the present disclosure;

FIG. 6 is a flowchart illustrating exemplary methods implemented in a communication system including a host computer, a network node and a wireless device for receiving user data from the wireless device at a host computer according to some embodiments of the present disclosure;

FIG. 7 is a flowchart illustrating exemplary methods implemented in a communication system including a host computer, a network node and a wireless device for receiving user data at a host computer according to some embodiments of the present disclosure;

FIG. 8 is a flowchart of an exemplary process in a network node according to some embodiments of the present disclosure;

FIG. 9 is a flowchart of an exemplary process in a wireless device according to some embodiments of the present disclosure;

FIG. 10 is a block diagram of an embodiment for multiplexing WUS and information data; FIG. 11 is a diagram of a WUS showing ON and OFF periods, the ON and OFF periods being dictated by the WUR data shown in FIG. 11;

FIG. 12 is a power spectral density of the signal of FIG. 11;

FIG. 13 is a block diagram of an alternative embodiment for multiplexing WUS and information data;

FIG. 14 is the power spectral density of the output of the OPT block of FIG. 13;

FIG. 15 is a plot of WUS which is the output of the OPT block of FIG. 13; and

FIG. 16 is a block diagram of an embodiment for computing a modified wake up signal.

DETAILED DESCRIPTION

Before describing in detail exemplary embodiments, it is noted that the embodiments reside primarily in combinations of apparatus components and processing steps related to generation and detection of amplitude shift keying (ASK) signals for a wake up receiver (WUR), some embodiments enabling generation and detection of an ASK signal at higher rates than known methods, where the ASK signal at the higher rate(s) may be referred to herein as a high rate ASK signal. Accordingly, components have been represented where appropriate by conventional symbols in the drawings, showing only those specific details that are pertinent to understanding the embodiments so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein. Like numbers refer to like elements throughout the description.

As used herein, relational terms, such as“first” and“second,”“top” and“bottom,” and the like, may be used solely to distinguish one entity or element from another entity or element without necessarily requiring or implying any physical or logical relationship or order between such entities or elements. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the concepts described herein. As used herein, the singular forms“a”,“an” and“the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms“comprises,”“comprising,”“includes” and/or“including” when used herein, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

In embodiments described herein, the joining term,“in communication with” and the like, may be used to indicate electrical or data communication, which may be accomplished by physical contact, induction, electromagnetic radiation, radio signaling, infrared signaling or optical signaling, for example. One having ordinary skill in the art will appreciate that multiple components may interoperate, and modifications and variations are possible of achieving the electrical and data communication.

In some embodiments described herein, the term“coupled,”“connected,” and the like, may be used herein to indicate a connection, although not necessarily directly, and may include wired and/or wireless connections.

The term“network node” used herein can be any kind of network node comprised in a radio network which may further comprise any of base station (BS), radio base station, base transceiver station (BTS), base station controller (BSC), radio network controller (RNC), g Node B (gNB), evolved Node B (eNB or eNodeB), Node B, multi- standard radio (MSR) radio node such as MSR BS, multi-cell/multicast coordination entity (MCE), relay node, donor node controlling relay, radio access point (AP), transmission points, transmission nodes, Remote Radio Unit (RRU) Remote Radio Head (RRH), a core network node (e.g., mobile management entity (MME), self-organizing network (SON) node, a coordinating node, positioning node, MDT node, etc.), an external node (e.g., 3rd party node, a node external to the current network), nodes in distributed antenna system (DAS), a spectrum access system (SAS) node, an element management system (EMS), etc. The network node may also comprise test equipment. The term“radio node” used herein may be used to also denote a wireless device (WD) such as a wireless device (WD) or a radio network node.

In some embodiments, the non-limiting terms wireless device (WD) or a user equipment (UE) are used interchangeably. The WD herein can be any type of wireless device capable of communicating with a network node or another WD over radio signals, such as wireless device (WD). The WD may also be a radio communication device, target device, device to device (D2D) WD, machine type WD or WD capable of machine to machine communication (M2M), low-cost and/or low-complexity WD, a sensor equipped with WD, Tablet, mobile terminals, smart phone, laptop embedded equipped (LEE), laptop mounted equipment (LME), USB dongles, Customer Premises Equipment (CPE), an Internet of Things (IoT) device, or a Narrowband IoT (NB-IOT) device etc.

Also, in some embodiments the generic term“radio network node” is used. It can be any kind of a radio network node which may comprise any of base station, radio base station, base transceiver station, base station controller, network controller, RNC, evolved Node B (eNB), Node B, gNB, Multi-cell/multicast Coordination Entity (MCE), relay node, access point, radio access point, Remote Radio Unit (RRU) Remote Radio Head (RRH). Note that although terminology from one particular wireless system, such as, for example, 3GPP LTE and/or New Radio (NR), may be used in this disclosure, this should not be seen as limiting the scope of the disclosure to only the aforementioned system. Other wireless systems, including without limitation Wide Band Code Division Multiple Access (WCDMA), Worldwide Interoperability for Microwave Access (WiMax), Ultra Mobile Broadband (UMB) and Global System for Mobile Communications (GSM), may also benefit from exploiting the ideas covered within this disclosure.

Note further, that functions described herein as being performed by a wireless device or a network node may be distributed over a plurality of wireless devices and/or network nodes. In other words, it is contemplated that the functions of the network node and wireless device described herein are not limited to performance by a single physical device and, in fact, can be distributed among several physical devices.

Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. It will be further understood that terms used herein should be interpreted as having a meaning that is consistent with their meaning in the context of this specification and the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

Embodiments provide power efficient WURs based at least in part on, for example, an envelope detector in a spectrally efficient way by multiplexing the WUS with the data. The multiplexing is performed in a way which may ensure that the performance for the data receivers are not degraded in a noticeable way compared to known methods, implying that the scheduling of the data can be done without any need to take the presence of a WUS into account. Note that although embodiments may be described when the WUS is modulated using OOK, the principles set forth herein are also applicable to ASK.

Referring again to the drawing figures, in which like elements are referred to by like reference numerals, there is shown in FIG. 2 a schematic diagram of a communication system 10, according to an embodiment, such as a 3 GPP -type cellular network that may support standards such as LTE and/or NR (5G), which comprises an access network 12, such as a radio access network, and a core network 14. The access network 12 comprises a plurality of network nodes 16a, 16b, 16c (referred to collectively as network nodes 16), such as NBs, eNBs, gNBs or other types of wireless access points, each defining a corresponding coverage area 18a, 18b, 18c (referred to collectively as coverage areas 18). Each network node 16a, 16b, 16c is connectable to the core network 14 over a wired or wireless connection 20. A first wireless device (WD) 22a located in coverage area 18a is configured to wirelessly connect to, or be paged by, the corresponding network node 16c. A second WD 22b in coverage area 18b is wirelessly connectable to the corresponding network node 16a. While a plurality of WDs 22a, 22b (collectively referred to as wireless devices 22) are illustrated in this example, the disclosed embodiments are equally applicable to a situation where a sole WD is in the coverage area or where a sole WD is connecting to the corresponding network node 16. Note that although only two WDs 22 and three network nodes 16 are shown for convenience, the communication system may include many more WDs 22 and network nodes 16.

Also, it is contemplated that a WD 22 can be in simultaneous communication and/or configured to separately communicate with more than one network node 16 and more than one type of network node 16. For example, a WD 22 can have dual connectivity with a network node 16 that supports LTE and the same or a different network node 16 that supports NR. As an example, WD 22 can be in communication with an eNB for LTE/E-UTRAN and a gNB for NR/NG-RAN.

The communication system 10 may itself be connected to a host computer 24, 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. The host computer 24 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. The connections 26, 28 between the communication system 10 and the host computer 24 may extend directly from the core network 14 to the host computer 24 or may extend via an optional intermediate network 30. The intermediate network 30 may be one of, or a combination of more than one of, a public, private or hosted network. The intermediate network 30, if any, may be a backbone network or the Internet. In some embodiments, the intermediate network 30 may comprise two or more sub networks (not shown).

The communication system of FIG. 2 as a whole enables connectivity between one of the connected WDs 22a, 22b and the host computer 24. The connectivity may be described as an over-the-top (OTT) connection. The host computer 24 and the connected WDs 22a, 22b are configured to communicate data and/or signaling via the OTT connection, using the access network 12, the core network 14, any intermediate network 30 and possible further infrastructure (not shown) as intermediaries. The OTT connection may be transparent in the sense that at least some of the participating communication devices through which the OTT connection passes are unaware of routing of uplink and downlink communications. For example, a network node 16 may not or need not be informed about the past routing of an incoming downlink communication with data originating from a host computer 24 to be forwarded (e.g., handed over) to a connected WD 22a. Similarly, the network node 16 need not be aware of the future routing of an outgoing uplink communication originating from the WD 22a towards the host computer 24.

A network node 16 is configured to include a multiplexer unit 32 which is configured to multiplex information data and a WUS. A wireless device 22 is configured to include a comparator unit 34 which is configured to compare a power of a WUS received by a first receiver having an envelope detector to a first threshold.

Example implementations, in accordance with an embodiment, of the WD 22, network node 16 and host computer 24 discussed in the preceding paragraphs will now be described with reference to FIG. 3. In a communication system 10, a host computer 24 comprises hardware (HW) 38 including a communication interface 40 configured to set up and maintain a wired or wireless connection with an interface of a different communication device of the communication system 10. The host computer 24 further comprises processing circuitry 42, which may have storage and/or processing capabilities. The processing circuitry 42 may include a processor 44 and memory 46. In particular, in addition to or instead of a processor, such as a central processing unit, and memory, the processing circuitry 42 may comprise integrated circuitry for processing and/or control, e.g., one or more processors and/or processor cores and/or FPGAs (Field Programmable Gate Array) and/or ASICs (Application Specific Integrated Circuitry) adapted to execute instructions. The processor 44 may be configured to access (e.g., write to and/or read from) memory 46, which may comprise any kind of volatile and/or nonvolatile memory, e.g., cache and/or buffer memory and/or RAM (Random Access Memory) and/or ROM (Read-Only Memory) and/or optical memory and/or EPROM (Erasable Programmable Read-Only Memory).

Processing circuitry 42 may be configured to control any of the methods and/or processes described herein and/or to cause such methods, and/or processes to be performed, e.g., by host computer 24. Processor 44 corresponds to one or more processors 44 for performing host computer 24 functions described herein. The host computer 24 includes memory 46 that is configured to store data, programmatic software code and/or other information described herein. In some embodiments, the software 48 and/or the host application 50 may include instructions that, when executed by the processor 44 and/or processing circuitry 42, causes the processor 44 and/or processing circuitry 42 to perform the processes described herein with respect to host computer 24. The instructions may be software associated with the host computer 24. The software 48 may be executable by the processing circuitry 42. The software 48 includes a host application 50. The host application 50 may be operable to provide a service to a remote user, such as a WD 22 connecting via an OTT connection 52 terminating at the WD 22 and the host computer 24. In providing the service to the remote user, the host application 50 may provide user data which is transmitted using the OTT connection 52. The“user data” may be data and information described herein as implementing the described functionality. In one embodiment, the host computer 24 may be configured for providing control and functionality to a service provider and may be operated by the service provider or on behalf of the service provider. The processing circuitry 42 of the host computer 24 may enable the host computer 24 to observe, monitor, control, transmit to and/or receive from the network node 16 and or the wireless device 22.

The communication system 10 further includes a network node 16 provided in a communication system 10 and including hardware 58 enabling it to communicate with the host computer 24 and with the WD 22. The hardware 58 may include a communication interface 60 for setting up and maintaining a wired or wireless connection with an interface of a different communication device of the communication system 10, as well as a radio interface 62 for setting up and maintaining at least a wireless connection 64 with a WD 22 located in a coverage area 18 served by the network node 16. The radio interface 62 may be formed as or may include, for example, one or more RF transmitters, one or more RF receivers, and/or one or more RF transceivers. The communication interface 60 may be configured to facilitate a connection 66 to the host computer 24. The connection 66 may be direct or it may pass through a core network 14 of the communication system 10 and/or through one or more intermediate networks 30 outside the communication system 10.

In the embodiment shown, the hardware 58 of the network node 16 further includes processing circuitry 68. The processing circuitry 68 may include a processor 70 and a memory 72. In particular, in addition to or instead of a processor, such as a central processing unit, and memory, the processing circuitry 68 may comprise integrated circuitry for processing and/or control, e.g., one or more processors and/or processor cores and/or FPGAs (Field Programmable Gate Array) and/or ASICs (Application Specific Integrated Circuitry) adapted to execute instructions. The processor 70 may be configured to access (e.g., write to and/or read from) the memory 72, which may comprise any kind of volatile and/or nonvolatile memory, e.g., cache and/or buffer memory and/or RAM (Random Access Memory) and/or ROM (Read-Only Memory) and/or optical memory and/or EPROM (Erasable Programmable Read-Only Memory). Thus, the network node 16 further has software 74 stored internally in, for example, memory 72, or stored in external memory (e.g., database, storage array, network storage device, etc.) accessible by the network node 16 via an external connection. The software 74 may be executable by the processing circuitry 68. The processing circuitry 68 may be configured to control any of the methods and/or processes described herein and/or to cause such methods, and/or processes to be performed, e.g., by network node 16. Processor 70 corresponds to one or more processors 70 for performing network node 16 functions described herein. The memory 72 is configured to store data, programmatic software code and/or other information described herein. In some embodiments, the software 74 may include instructions that, when executed by the processor 70 and/or processing circuitry 68, causes the processor 70 and/or processing circuitry 68 to perform the processes described herein with respect to network node 16. For example, processing circuitry 68 of the network node 16 may include multiplexer unit 32 configured to multiplex information data and a WUS.

The communication system 10 further includes the WD 22 already referred to. The WD 22 may have hardware 80 that may include a radio interface 82 configured to set up and maintain a wireless connection 64 with a network node 16 serving a coverage area 18 in which the WD 22 is currently located. The radio interface 82 may be formed as or may include, for example, one or more RF transmitters, one or more RF receivers, and/or one or more RF transceivers. In particular, in some embodiments, the radio interface 82 may include a first WUR 82A, which may have an envelope detector, and a second WUR 82B, which may have a phase detector. For example, in some embodiments, the envelope detector of the first WUR 82A detects an envelope of a WUS received by the first WUR 82 A in order to determine a power of the WUS. Comparator unit 34 may compare the determined power to a first threshold. If the determined power falls below the threshold, the second WUR 82B may operate to detect a phase of the WUS.

The hardware 80 of the WD 22 further includes processing circuitry 84. The processing circuitry 84 may include a processor 86 and memory 88. In particular, in addition to or instead of a processor, such as a central processing unit, and memory, the processing circuitry 84 may comprise integrated circuitry for processing and/or control, e.g., one or more processors and/or processor cores and/or FPGAs (Field Programmable Gate Array) and/or ASICs (Application Specific Integrated Circuitry) adapted to execute instructions. The processor 86 may be configured to access (e.g., write to and/or read from) memory 88, which may comprise any kind of volatile and/or nonvolatile memory, e.g., cache and/or buffer memory and/or RAM (Random Access Memory) and/or ROM (Read-Only Memory) and/or optical memory and/or EPROM (Erasable Programmable Read-Only Memory).

Thus, the WD 22 may further comprise software 90, which is stored in, for example, memory 88 at the WD 22, or stored in external memory (e.g., database, storage array, network storage device, etc.) accessible by the WD 22. The software 90 may be executable by the processing circuitry 84. The software 90 may include a client application 92. The client application 92 may be operable to provide a service to a human or non-human user via the WD 22, with the support of the host computer 24. In the host computer 24, an executing host application 50 may communicate with the executing client application 92 via the OTT connection 52 terminating at the WD 22 and the host computer 24. In providing the service to the user, the client application 92 may receive request data from the host application 50 and provide user data in response to the request data. The OTT connection 52 may transfer both the request data and the user data. The client application 92 may interact with the user to generate the user data that it provides.

The processing circuitry 84 may be configured to control any of the methods and/or processes described herein and/or to cause such methods, and/or processes to be performed, e.g., by WD 22. The processor 86 corresponds to one or more processors 86 for performing WD 22 functions described herein. The WD 22 includes memory 88 that is configured to store data, programmatic software code and/or other information described herein. In some embodiments, the software 90 and/or the client application 92 may include instructions that, when executed by the processor 86 and/or processing circuitry 84, causes the processor 86 and/or processing circuitry 84 to perform the processes described herein with respect to WD 22. For example, the processing circuitry 84 of the wireless device 22 may include a comparator unit 34 configured to compare a power of a WUS received by a first receiver having an envelope detector to a first threshold.

In some embodiments, the inner workings of the network node 16, WD 22, and host computer 24 may be as shown in FIG. 3 and independently, the surrounding network topology may be that of FIG. 2.

In FIG. 3, the OTT connection 52 has been drawn abstractly to illustrate the communication between the host computer 24 and the wireless device 22 via the network node 16, 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 the WD 22 or from the service provider operating the host computer 24, or both. While the OTT connection 52 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).

The wireless connection 64 between the WD 22 and the network node 16 is in accordance with the teachings of the embodiments described throughout this disclosure. One or more of the various embodiments improve the performance of OTT services provided to the WD 22 using the OTT connection 52, in which the wireless connection 64 may form the last segment. More precisely, the teachings of some of these embodiments may improve the data rate, latency, and/or power consumption and thereby provide benefits such as reduced user waiting time, relaxed restriction on file size, better responsiveness, extended battery lifetime, etc.

In some embodiments, 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 the OTT connection 52 between the host computer 24 and WD 22, in response to variations in the measurement results. The measurement procedure and/or the network functionality for reconfiguring the OTT connection 52 may be implemented in the software 48 of the host computer 24 or in the software 90 of the WD 22, or both. In embodiments, sensors (not shown) may be deployed in or in association with communication devices through which the OTT connection 52 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 48, 90 may compute or estimate the monitored quantities. The reconfiguring of the OTT connection 52 may include message format, retransmission settings, preferred routing etc.; the reconfiguring need not affect the network node 16, and it may be unknown or imperceptible to the network node 16. Some such procedures and functionalities may be known and practiced in the art. In certain embodiments, measurements may involve proprietary WD signaling facilitating the host computer’s 24 measurements of throughput, propagation times, latency and the like. In some embodiments, the measurements may be implemented in that the software 48, 90 causes messages to be transmitted, in particular empty or‘dummy’ messages, using the OTT connection 52 while it monitors propagation times, errors etc.

Thus, in some embodiments, the host computer 24 includes processing circuitry 42 configured to provide user data and a communication interface 40 that is configured to forward the user data to a cellular network for transmission to the WD 22. In some embodiments, the cellular network also includes the network node 16 with a radio interface 62. In some embodiments, the network node 16 is configured to, and/or the network node’s 16 processing circuitry 68 is configured to perform the functions and/or methods described herein for preparing/initiating/maintaining/supporting/ending a transmission to the WD 22, and/or preparing/terminating/maintaining/supporting/ending in receipt of a transmission from the WD 22

In some embodiments, the host computer 24 includes processing circuitry 42 and a communication interface 40 that is configured to a communication interface 40 configured to receive user data originating from a transmission from a WD 22 to a network node 16. In some embodiments, the WD 22 is configured to, and/or comprises a radio interface 82 and/or processing circuitry 84 configured to perform the functions and/or methods described herein for preparing/initiating/maintaining/supporting/ending a transmission to the network node 16, and/or preparing/terminating/maintaining/supporting/ending in receipt of a transmission from the network node 16. The radio interface 82 also includes a wake up receiver (WUR) configured to receive and detect a wake up signal (WUS).

Although FIGS. 2 and 3 show various“units” such as multiplexer unit 32, and comparator unit 34 as being within a respective processor, it is contemplated that these units may be implemented such that a portion of the unit is stored in a corresponding memory within the processing circuitry. In other words, the units may be implemented in hardware or in a combination of hardware and software within the processing circuitry.

FIG. 4 is a flowchart illustrating an exemplary method implemented in a communication system, such as, for example, the communication system of FIGS. 2 and 3, in accordance with one embodiment. The communication system may include a host computer 24, a network node 16 and a WD 22, which may be those described with reference to FIG. 3. In a first step of the method, the host computer 24 provides user data (Block SI 00). In an optional sub step of the first step, the host computer 24 provides the user data by executing a host application, such as, for example, the host application 50 (Block SI 02). In a second step, the host computer 24 initiates a transmission carrying the user data to the WD 22 (Block S 104). In an optional third step, the network node 16 transmits to the WD 22 the user data which was carried in the transmission that the host computer 24 initiated, in accordance with the teachings of the embodiments described throughout this disclosure (Block S106). In an optional fourth step, the WD 22 executes a client application, such as, for example, the client application 114, associated with the host application 50 executed by the host computer 24 (Block SI 08).

FIG. 5 is a flowchart illustrating an exemplary method implemented in a communication system, such as, for example, the communication system of FIG. 2, in accordance with one embodiment. The communication system may include a host computer 24, a network node 16 and a WD 22, which may be those described with reference to FIGS. 2 and 3. In a first step of the method, the host computer 24 provides user data (Block SI 10). In an optional sub step (not shown) the host computer 24 provides the user data by executing a host application, such as, for example, the host application 50. In a second step, the host computer 24 initiates a transmission carrying the user data to the WD 22 (Block SI 12). The transmission may pass via the network node 16, in accordance with the teachings of the embodiments described throughout this disclosure. In an optional third step, the WD 22 receives the user data carried in the transmission (Block SI 14).

FIG. 6 is a flowchart illustrating an exemplary method implemented in a communication system, such as, for example, the communication system of FIG. 2, in accordance with one embodiment. The communication system may include a host computer 24, a network node 16 and a WD 22, which may be those described with reference to FIGS. 2 and 3. In an optional first step of the method, the WD 22 receives input data provided by the host computer 24 (Block SI 16). In an optional substep of the first step, the WD 22 executes the client application 114, which provides the user data in reaction to the received input data provided by the host computer 24 (Block SI 18). Additionally or alternatively, in an optional second step, the WD 22 provides user data (Block S120). In an optional substep of the second step, the WD provides the user data by executing a client application, such as, for example, client application 114 (Block S122). In providing the user data, the executed client application 114 may further consider user input received from the user. Regardless of the specific manner in which the user data was provided, the WD 22 may initiate, in an optional third substep, transmission of the user data to the host computer 24 (Block S124). In a fourth step of the method, the host computer 24 receives the user data transmitted from the WD 22, in accordance with the teachings of the embodiments described throughout this disclosure (Block S126).

FIG. 7 is a flowchart illustrating an exemplary method implemented in a communication system, such as, for example, the communication system of FIG. 2, in accordance with one embodiment. The communication system may include a host computer 24, a network node 16 and a WD 22, which may be those described with reference to FIGS. 2 and 3. In an optional first step of the method, in accordance with the teachings of the embodiments described throughout this disclosure, the network node 16 receives user data from the WD 22 (Block S128). In an optional second step, the network node 16 initiates transmission of the received user data to the host computer 24 (Block S130). In a third step, the host computer 24 receives the user data carried in the transmission initiated by the network node 16 (Block SI 32). FIG. 8 is a flowchart of an exemplary process in a network node 16 for generation of a high rate amplitude shift keying (ASK) signal accordance with principles of the present disclosure. One or more blocks described herein may be performed by one or more elements of network node 16 such as by one or more of processing circuitry 68 (including the multiplexer unit 32), processor 70, radio interface 62 and/or communication interface 60. Network node 16 such as via processing circuitry 68 and/or processor 70 and/or radio interface 62 and/or communication interface 60 is configured to determine a first wake up signal, WUS, the first WUS being configured to indicate when the network node 16 has data intended for the WD 22, the first WUS having first information being embedded in an amplitude of the WUS (Block SI 34). Network node 16 such as via processing circuitry 68 and/or processor 70 and/or radio interface 62 and/or communication interface 60 is further configured to modify the first WUS to produce a second WUS, the second WUS having less energy leakage at least one neighboring band of the first WUS than the first WUS (Block SI 36 Network node 16 such as via processing circuitry 68 and/or processor 70 and/or radio interface 62 and/or communication interface 60 is further configured to multiplex information data with the second WUS to produce a multiplexed signal, the information data being carried in the neighboring band of the first WUS (Block SI 38), and send the multiplexed signal to the WD 22 (Block S140).

FIG. 9 is a flowchart of an exemplary process in a wireless device 22 according to some embodiments of the present disclosure. One or more Blocks described herein may be performed by one or more elements of wireless device 22 such as by one or more of processing circuitry 84 (including the comparator unit 34), processor 86, radio interface 82 and/or communication interface 60. Wireless device 22 such as via processing circuitry 84 and/or processor 86 and/or radio interface 82 is configured to detect, using an envelope detector, an envelope of a wake up signal, WUS, received by a first receiver to determine a power of the WUS (Block S142). Wireless device 22 such as via processing circuitry 84 and/or processor 86 and/or radio interface 82 is configured to compare the determined power to a first threshold (Block S144). Wireless device 22 such as via processing circuitry 84 and/or processor 86 and/or radio interface 82 is configured to, if the determined power falls below the first threshold (Block SI 46), use a second receiver to detect a phase of the WUS (Block S148).

Having described the general process flow of arrangements of the disclosure and having provided examples of hardware and software arrangements for implementing the processes and functions of the disclosure, the sections below provide details and examples of arrangements for generation of ASK signals for a WUR, some embodiments enabling generation and detection of a high rate amplitude shift keying signal. Embodiments are presented as being applied to a specific system with specific parameters to more easily describe the concepts set forth herein. As would be obvious for anyone of ordinary skill in the art, the ideas presented here are easily adopted to other systems with potentially very different parameters.

Parameters corresponding to the transmission of a New Radio (NR) or Fifth Generation (5G) signal in a 20 MHz channel are employed in some embodiments. Specifically, in one example, the sampling rate is 30.72 MHz and a 2048-point inverse fast Fourier transform (IFFT) is used to generate the signal. This implies that an OFDM symbol consists of 2048 samples to which, typically a cyclic prefix (CP) of 144 samples are added so that the total duration becomes 2192 samples with a total duration of roughly 71 us.

The WUS can be sent by multiplexing it, via the multiplexer unit 32, with data. Schematically, an example of this is illustrated in FIG. 10. As seen in FIG. 10, some of the bandwidth that could be used for data transmission is not used as indicated by the 0 input to some inputs of the IFFT 100 which may be added to a CP 101. In parallel, the WUS is generated by, for example, modulating some WUR data, via the modulator 102 and then frequency shifting this modulated data, via the frequency shifter 104, so that its frequency contents fit within the bandwidth (BW) not used for sending data. The modulating and/or frequency shifting may be performed by the radio interface 62. The IFFT 100 output plus CP 101 may be added to the modulated, frequency shifted WUR data by the adder 106.

In order to reduce the leakage that may result, there may need to be a guard band between the WUR and the data, i.e., the bandwidth of the WUS may be significantly less than the bandwidth not used for sending data. Alternatively, in case the symbol rate of the WUS is only slightly larger than the OFDM symbol rate, one may try to populate the corresponding sub-carriers such that an approximation of the desired WUS is obtained. However, if it is desirable to have a symbol rate of the WUS that is considerably higher than the OFDM symbol rate, these approaches might not be feasible, in some embodiments.

In FIG. 11, shows the amplitude of the WUS generated as described in FIG. 10. In the example shown in FIG. 11, the WUR data consists of 85 bits of information, where the ON and OFF periods are of 24 samples in duration. This is shown by the rectangular pulses in FIG. 11. A bandwidth of 1 MHz in a total of a 20 MHz bandwidth is allocated to the WUS which is obtained by the process of modulation and frequency shift as shown in FIG. 10. The resulting WUS envelope is shown in FIG. 11 represented by the non-rectangular waveforms between the rectangular pulses. In FIG. 12, the spectrum of the WUS signal shown in FIG. 11 is plotted. As illustrated in FIG. 12, the leakage caused to the adjacent bands by the WUS can be large depending upon the system parameters and scenario. Thus, some embodiments are configured to generate a high-rate WUS signal while at the same time keeping the leakage below a desired level. This can be achieved as described below.

Embodiment 1 : TX part - WUS signal design

According to this embodiment, the WUS is constructed in such a way that the information in the WUS is contained in the amplitude at the same time as the specific waveform is designed such that the caused leakage to the data sent at adjacent frequencies is kept low compared to known methods.

An illustration of such an implementation is illustrated in FIG. 13. One or more of IFFT 100, CP 101, modulator 102, frequency shifter 104, optimizer 105 and adder 106 may be provided by one or more of radio interface 82, processing circuitry 84, etc. Here the WUS obtained with reference to FIG. 10 is denoted WUS’. This signal, i.e., WUS’, is then sent to a block denoted OPT 105 (i.e., optimizer 105) which modifies the WUS’ to WUS such that it remains similar to WUS’ but with considerably less energy leaking into the bandwidth used for sending data compared to known methods.

An example the operation of this OPT 105 block may be as follows:

• Prior to optimization, the OPT 105 block first determines the adjacent band of subcarriers that comprise the data. This band is represented by a matrix Q, i.e., the columns of the matrix Q constitute the data subcarriers. The total bandwidth including the WUS bandwidth is represented by a matrix F which is the IFFT matrix. The columns of Q form a subset of the columns of F.

• Denote the WUS’ input to the OPT 105 block, in FIG. 13, by w' and the WUS output of OPT 105 by w = Fx, where x is a variable to be determine. By determining x, w is determined.

• The objective of the OPT 105 block may be as follows: To seek a w that is as close as possible to its input w', while at the same time minimizing the leakage that w causes to the adjacent band represented by Q. This can be mathematically expressed as: where in the above minimization, a is a tunable parameter that controls the leakage. The higher the value of a, the lower is the leakage to neighboring subcarriers and vice-versa. The first term in the minimization problem above represents the closeness to w', while the second term represents the total leakage caused by w = Fx to the entire adjacent band represented by the matrix Q.

• The solution to the minimization problem above is a smooth convex function whose solution is given by w' = pinv(I + crF ^† QQ ^† F)F ^† w', where pinv( *) denotes pseudo-inverse of the matrix inside the parentheses and / is the identity matrix.

• The OPT 105 block outputs w which is computed according to the above equation.

The OPT 105 block may be implemented in the radio interface 62 or by the processing circuitry 68.

As an example, FIGS. 14 and 15 show, respectively, the spectrum and envelope of the WUS signal designed and/or generated by the OPT 105 block for different values of a. As illustrated in FIG. 14, for a given choice of a, the resulting WUS signal designed by the OPT 105 block has lower leakage compared to the WUS’ signal that is input to the OPT 105 block. The higher the values of a, the larger is the leakage power suppression.

The corresponding signal amplitude (envelope) of the designed WUS signals are shown in FIG. 15, for this example. As is illustrated in FIG. 15, the designed WUS signals do not have the exact same envelope of the input WUS’ signal. This is evident during the OFF-periods, where there is a non-zero amplitude for the WUS signals during the OFF- period. This slight loss in approximation accuracy may be a trade off to achieve a larger leakage suppression.

An alternative to the above optimization criteria on minimizing the total out-of-band power constraint on the maximum energy on any individual

subcarrier. The problem will then turn into a quadratically constrained convex problem. Either the constraint value can be fixed, or be minimized in the goal function. This limitation on the maximum value may serve as a power spectral density (PSD) constraint on the out-of- band emissions, and can, in some embodiments, at least help guarantee the performance for wireless devices 22 with a narrow frequency allocation close to the WUS band. Another alternative is to assign some random data to the WUS subcarriers via the processing circuitry 68. Other alternatives also exist, such as assigning a constant complex value, or a pre-defmed vector of complex values, for example. In addition, in some or all of these cases, a windowing function can also be applied, limiting the power near the edges of the WUS band, thereby limiting the leakage outside the WUS band.

In another approach, the radio interface/transceiver 62 can skip the OPT 105 step if there is a sufficient guard band between the WUS and the data. For example, if there is no data over a number of subcarriers immediately next to the WUS, the radio interface/transceiver 62 can help ensure the data is not affected and thus skip the OPT 105 box. As such, the radio interface/transceiver 62 can have a criterion to skip or activate the OPT 105 box.

Embodiments are not limited to a specific way of generating the WUS signal. Rather some embodiments relate to the design of a desired signal carrying information in the amplitude within a certain bandwidth at the same time the energy outside of this bandwidth is kept at a low enough level, where a low enough level relates to the signal -to-noise ratio (SNR) needed to demodulate the data, according to some embodiments.

One specific example of how the WUS’ may be generated is depicted in FIG. 16. In this case, the same transmitter structure as used for the data is implemented, but now with WUR data transmitted on the sub-carriers that are not used for data and nothing is sent on the sub carriers that are typically used for data. A cyclic prefix (CP) 101 may then be added to the output of the IFFT 100 as is typically done in existing OFDM. Adding a CP 101 has the advantage that the WUS’ signal becomes slightly longer which can be beneficial from a performance point of view. In addition, if the duration of the WUS’ is more than one symbol, e.g., corresponds to two or three symbols, adding a CP 101 has the advantage that the symbol boundaries for the data and symbols in the WUS may coincide. The signal is then multiplied 108 with the WUR data via multiplexer unit 32, which for instance may be OOK as illustrated in FIG. 16.

If the same WUR data is used to generate the WUS every time, the optimization 105 may only need to be performed once, and the resulting WUS could just be stored in memory 72 and reused every time a WUS is to be transmitted. The transmitting can be done via radio interface 62.

As another example for generating the WUS’, one may let WUS’ = WUR data.

Embodiment 2: RX part - Selective use of an envelope detector

Although the WUR information can be extracted from the amplitude of the signal alone by an envelope detector such as an envelope detector that is part of the first WUR 82A, improved detector performance can be obtained if information of the phase is extracted, which can be performed by a phase detector of a second WUR 82B. This may imply that complex processing of second WUR 82B may be required so that both the in-phase and the quadrature component of the signal may be extracted. Compared to only considering the envelope of the signal as in first WUR 82A, there may be more stringent requirements on the receiver of the radio interface 82 in terms of frequency and phase stability for such complex processing as may be performed by second WUR 82B, thus implying an increased power consumption.

According to this embodiment, two types of WURs in the radio interface 82 for the WUS are supported in a wireless device 22. The first type of WUR 82A may only use the information in the envelope of the signal, whereas the second type of WUR 82B also uses information carried in the phase. Furthermore, the WD 22 determines whether it is expected that the first WUR 82A will result in sufficiently good performance or satisfactory performance (i.e., performance meeting a predefined criterion) or if the second WUR 82B needs to be used in order result in the sufficiently good performance. Thus, in some embodiments, the more complex processing of the second type of WUR 82B is not executed when at least satisfactory performance can be achieved by the simpler processing of the first WUR 82A.

One metric that may be used by WD 22 to determine whether the first WUR 82a suffices, is the expected SNR of the WUS (i.e., comparing expected SNR of the WUS to a predefined SNR threshold). If the expected SNR of the WUS is determined to be sufficiently high, as determined by the comparator unit 34, the WD 22 may then use only the first WUR 82A for reception of the WUS, otherwise the second WUR 82B will be used instead. For example, in case of NR, if the reference signal received power (RSRP) is more than a threshold, the WD 22 can employ the simpler detector of the first WUR 82A, while if the RSRP is lower than a threshold, the WD 22 can employ a more complicated detector of the second WUR 82B. Furthermore, if the RSRP is very low, i.e., less than a second threshold which is much less than the normal threshold, the NR WD 22 can decide to ignore the WUS detection all together, and wake up the WD 22 to make sure the WUS is not missed.

Another metric that may be used by the device to determine whether the first WUR 82A suffices is whether the frequency and phase accuracies are considered to be sufficiently high. In case the frequency and phase accuracy is considered to not be sufficiently high, the first WUR 82A will be used, whereas if higher performance is needed and the frequency and phase accuracies are considered to be sufficiently high, the second WUR 82B may be used instead. The needed level of accuracy may be dependent on various measurements, e.g., SNR/RSRP as described above, or measured Doppler or delay spread, in some embodiments, Other types of receivers may be implemented. For example, the receiver implemented in radio interface 82 can employ edge detection techniques to discover the 0, 1 pattern of the received signal in time. Similar to envelope detection, edge detection also has a lower complexity. A special class of edge detectors are wavelet detectors. In case the phase offset remains relatively the same for all the subcarriers (which, because of a low bandwidth (BW), is a reasonable assumption), the wavelet detector may still be able to discover the edges even if the phase synchronization is not very accurate.

In another realization, the receiver/receiver interface 82 can consider a two-step process where in the first step, a simple detector is used within the WUS bandwidth to detect the presence of the WUS, and if there is an indication of a WUS presence, then the receiver can implement more sophisticated detectors to at least help ensure the WUS is indeed intended for this receiver/receiver interface 82. One realization of this detector is right after the fast Fourier transform (FFT), by spectral detection within the WUS bandwidth.

Some embodiments include a network node 16 configured to determine a first wake up signal, WUS, the first WUS being configured to indicate when the network node 16 has data intended for the WD 22, the WUS having information embedded in an amplitude of the WUS. The network node 16 is further configured to modify the first WUS to produce a second WUS, the second WUS having less energy leakage into an information band than the first WUS. The network node 16 is further configured to multiplex information data with the second WUS to produce a multiplexed signal, the information data being carried in a subband that neighbors a band of the first WUS; and send the multiplexed signal to the WD 22.

According to this aspect, in some embodiments, the modifying of the first WUS includes determining an optimization of an objective function that is based at least in part on the first WUS. In some embodiments, the objective function includes a matrix having columns that correspond to subcarriers for carrying the information data.

According to another aspect, a wireless device 22 is configured to compare a power of a WUS received by a first receiver having an envelope detector to a first threshold. The WD 22 is further configured to, if the power of the received WUS falls below the first threshold, using a second receiver to detect the WUS, the second receiver detecting a phase of the WUS.

According to this aspect, in some embodiments, if the power of the received WUS is less than a second threshold lower than the first threshold, the WD 22 ignores the WUS and enters a wake state.

According to another aspect, a network node 16 is configured to communicate with a wireless device, WD 22. The network node includes processing circuitry 68 configured to: determine a first wake up signal, WUS, the first WUS being configured to indicate when the network node has data intended for the WD, the first WUS having first information being embedded in an amplitude of the WUS. The processing circuitry 68 is further configured to modify the first WUS to produce a second WUS, the second WUS having less energy leakage into at least one neighboring band of the first WUS than the first WUS. The processing circuitry 68 is further configured to multiplex information data with the second WUS to produce a multiplexed signal, the information data being carried by subcarriers in the neighboring band of the first WUS. The network node 16 also includes a radio interface 62 configured to send the multiplexed signal to the WD 22.

According to this aspect, in some embodiments, the modifying includes determining, via the processing circuitry 68, an optimization of an objective function that is based at least in part on the first WUS. In some embodiments, the objective function includes a matrix having columns that correspond to sub carriers carrying the information data and the second WUS. In some embodiments, at least one matrix column further corresponds to at least one subcarrier of at least one neighboring band. In some embodiments, the modifying includes modulating the information data, and frequency shifting the modulated data so that frequency content of the modulated data falls within a bandwidth not used for sending other data.

According to yet another aspect, a method implemented in a network node 16 includes determining a first wake up signal, WUS, the first WUS being configured to indicate when the network node 16 has data intended for the WD 22, the first WUS having first information being embedded in an amplitude of the WUS. The method further includes modifying, via the processing circuitry 68, the first WUS to produce a second WUS, the second WUS having less energy leakage into at least one neighboring band of the first WUS than the first WUS. The method further includes multiplexing, via the processing circuitry 68, information data with the second WUS to produce a multiplexed signal, the information data being carried by subcarriers in the neighboring band of the first WUS, and sending the multiplexed signal to the WD 22.

According to this aspect, in some embodiments, the modifying, via the processing circuitry 68, includes determining an optimization of an objective function that is based at least in part on the first WUS. In some embodiments, the objective function includes a matrix having columns that correspond to sub carriers carrying the information data and the second WUS. In some embodiments, at least one matrix column further corresponds to at least one subcarrier of at least one neighboring band. In some embodiments, the modifying includes modulating, via the radio interface 62, the information data, and frequency shifting the modulated data so that frequency content of the modulated data falls within a bandwidth not used for sending other data.

According to another aspect, a WD 22 is configured to communicate with a network node 16. The WD 22 includes processing circuitry 84 configured to: detect, using an envelope detector, an envelope of a wake up signal, WUS, received by a first receiver 82 A of the radio interface 82, to determine a power of the WUS, compare, via the processing circuitry 84, the determined power to a first threshold, and if the determined power falls below the first threshold, using a second receiver 82B of the radio interface 82, to detect a phase of the WUS.

According to this aspect, in some embodiments, if the power of the received WUS is less than a second threshold lower than the first threshold, the WD 22 ignores the WUS and enters a wake state. In some embodiments, the second receiver 82B is a principal communication receiver responsive to a wakeup signal from the first receiver 82A. In some embodiments, the processing circuitry is further configured to first detect a presence of the WUS, followed by determining whether the WUS is intended for the WD 22.

According to yet another aspect, a method implemented in a wireless device, WD 22, includes detecting, using an envelope detector implemented by the processing circuitry 84 and/or radio interface 82„ an envelope of a wake up signal, WUS, received by a first receiver 82A to determine a power of the WUS, comparing, via the comparator unit 34, the determined power to a first threshold, and if the determined power falls below the first threshold, using a second receiver 82B to detect a phase of the WUS.

According to this aspect, in some embodiments, if the power of the received WUS is less than a second threshold lower than the first threshold, the WD 22 ignores the WUS and enters a wake state. In some embodiments, the second receiver 82B is a principal communication receiver responsive to a wakeup signal from the first receiver 82A. In some embodiments, the method further includes first detecting a presence of the WUS, followed by determining whether the WUS is intended for the WD 22.

Some embodiments include:

Embodiment Al . A network node 16 configured to communicate with a wireless device 22 (WD 22), the network node 16 configured to, and/or comprising a radio interface 62 and/or comprising processing circuitry 68 configured to:

determine a first wake up signal, WUS, the first WUS being configured to indicate when the network node 16 has data intended for the WD 22;

modify the first WUS to produce a second WUS, the second WUS having less energy leakage into an information band than the first WUS; multiplex information data with the second WUS to produce a multiplexed signal; and send the multiplexed signal to the WD 22.

Embodiment A2. The network node 16 of Embodiment A1 , wherein the modifying includes an determining an optimization of an objective function that is based at least in part on the first WUS.

Embodiment A3. The network node 16 of Embodiment A2, wherein the objective function includes a matrix having columns that correspond to subcarriers for carrying the information data.

Embodiment Bl . A method implemented in a network node 16, the method comprising:

determining a first wake up signal, WUS, the first WUS being configured to indicate when the network node 16 has data intended for the WD 22;

modifying the first WUS to produce a second WUS, the second WUS having less energy leakage into an information band than the first WUS;

multiplexing information data with the second WUS to produce a multiplexed signal; and

sending the multiplexed signal to the WD 22.

Embodiment B2. The method of Embodiment Bl, wherein the modifying includes an determining an optimization of an objective function that is based at least in part on the first WUS.

Embodiment B3. The method of Embodiment B2, wherein the objective function includes a matrix having columns that correspond to subcarriers for carrying the information data.

Embodiment Cl . A wireless device 22 (WD 22) configured to communicate with a network node 16, the WD 22 configured to, and/or comprising a radio interface 82 and/or processing circuitry 84 configured to:

compare a power of a WUS received by a first receiver having an envelope detector to a first threshold; and

if the power of the received WUS falls below the first threshold, using a second receiver to detect the WUS, the second receiver detecting a phase of the WUS.

Embodiment C2. The WD 22 of Embodiment Cl, wherein if the power of the received WUS is less than a second threshold lower than the first threshold, the WD 22 ignores the WUS and enters a wake state. Embodiment Dl . A method implemented in a wireless device 22 (WD 22), the method comprising:

comparing a power of a WUS received by a first receiver having an envelope detector to a first threshold; and

if the power of the received WUS falls below the first threshold, using a second receiver to detect the WUS, the second receiver detecting a phase of the WUS.

Embodiment D2. The method of Embodiment Dl, wherein if the power of the received WUS is less than a second threshold lower than the first threshold, the WD 22 ignores the WUS and enters a wake state.

As will be appreciated by one of skill in the art, the concepts described herein may be embodied as a method, data processing system, computer program product and/or computer storage media storing an executable computer program. Accordingly, the concepts described herein may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects all generally referred to herein as a“circuit” or“module.” Any process, step, action and/or functionality described herein may be performed by, and/or associated to, a corresponding module, which may be implemented in software and/or firmware and/or hardware. Furthermore, the disclosure may take the form of a computer program product on a tangible computer usable storage medium having computer program code embodied in the medium that can be executed by a computer. Any suitable tangible computer readable medium may be utilized including hard disks, CD- ROMs, electronic storage devices, optical storage devices, or magnetic storage devices.

Some embodiments are described herein with reference to flowchart illustrations and/or block diagrams of methods, systems and computer program products. It will be understood that each block of the flowchart illustrations and/or block diagrams, and combinations of blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer (to thereby create a special purpose computer), special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks.

These computer program instructions may also be stored in a computer readable memory or storage medium that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer readable memory produce an article of manufacture including instruction means which implement the function/act specified in the flowchart and/or block diagram block or blocks.

The computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks.

It is to be understood that the functions/acts noted in the blocks may occur out of the order noted in the operational illustrations. For example, two blocks shown in succession may in fact be executed substantially concurrently or the blocks may sometimes be executed in the reverse order, depending upon the functionality/acts involved. Although some of the diagrams include arrows on communication paths to show a primary direction of communication, it is to be understood that communication may occur in the opposite direction to the depicted arrows.

Computer program code for carrying out operations of the concepts described herein may be written in an object oriented programming language such as Java® or C++. However, the computer program code for carrying out operations of the disclosure may also be written in conventional procedural programming languages, such as the "C" programming language. The program code may execute entirely on the user's computer, partly on the user's computer, as a stand-alone software package, partly on the user's computer and partly on a remote computer or entirely on the remote computer. In the latter scenario, the remote computer may be connected to the user's computer through a local area network (LAN) or a wide area network (WAN), or the connection may be made to an external computer (for example, through the Internet using an Internet Service Provider).

Many different embodiments have been disclosed herein, in connection with the above description and the drawings. It will be understood that it would be unduly repetitious and obfuscating to literally describe and illustrate every combination and subcombination of these embodiments. Accordingly, all embodiments can be combined in any way and/or combination, and the present specification, including the drawings, shall be construed to constitute a complete written description of all combinations and subcombinations of the embodiments described herein, and of the manner and process of making and using them, and shall support claims to any such combination or subcombination.

Abbreviations that may be used in the preceding description include:

Abbreviation Explanation CP Cyclic Prefix

DFT Discrete Fourier Transform

FFT Fast Fourier Transform

IFFT Inverse FFT

MC-OOK Multicarrier-OOK

OFDM Orthogonal Frequency Division Multiplexing

OOK On-Off Keying

PCR Primary Connectivity Radio

RF Radio Frequency

WUR Wake-Up Radio

WURx Wake-Up Receiver

WUS Wake-Up Signal

It will be appreciated by persons skilled in the art that the embodiments described herein are not limited to what has been particularly shown and described herein above. In addition, unless mention was made above to the contrary, it should be noted that all of the accompanying drawings are not to scale. A variety of modifications and variations are possible in light of the above teachings without departing from the scope of the following claims.