Methods and apparatus for transmission and detection of multi-band wake-up

Multi-band Wake-up (MWU) signal transmission and detection is disclosed. A transmitter determines a MWU signal that indicates availability of one or more sub-bands to a first user in a serving cell, and transmits the MWU signal for the one or more sub-bands in the serving cell. A clear channel assessment (CCA) status on the one or more sub-bands that are available to the first user is carried by the payload of MWU signals. The MWU signal includes a first user identifier that identifies the first user as a targeted receiver of the MWU signal. The first user has priority over a second user to utilize the one or more sub-bands. Correspondingly, a receiver receives a MWU signal for one or more sub-bands in the serving cell, decodes a payload of the MWU signal, and determines availability of the one or more sub-bands to the first user based on the payload of the MWU signal.

BACKGROUND

Field

Aspects of the present disclosure relate generally to wireless communication systems, and more particularly, to transmission and detection of multi-band wake-up signals.

BACKGROUND

New radio (NR) networks support scalable OFDM numerology and flexible channel bandwidth design for both a network and a UE. For example, for the frequency range of sub to six (6) GHz, a channel bandwidth may vary between five (5) MHz and one hundred (100) MHz. As a further example, for the frequency above twenty-four (24) GHz, a channel bandwidth may vary between fifty (50) MHz and four hundred (400) MHz. A wideband spectrum can be divided into multiple non-overlapping sub-bands. A network node may perform a listen before talk (LBT) procedure prior to using a certain sub-band in order to determine whether this sub-band is reserved. A sub-band based LBT may maximize a re-use factor of radio resources. The transmission opportunity (TxOP) after each LBT may be associated with different combinations of sub-bands. It may be beneficial for both a desirable user and an aggressor to be timely informed of multi-band medium sharing status for efficient utilization of sub-bands in unlicensed spectrum.

SUMMARY

In one aspect of the present disclosure, a method of wireless communication is provided. The method includes determining a multi-band wake-up (MWU) signal that indicates availability of one or more sub-bands to a first user in a serving cell, a clear channel assessment (CCA) on the one or more sub-bands that are available to the first user being clear, the MWU signal including a first user identifier that identifies the first user as a targeted receiver of the MWU signal, the first user having priority over a second user in the serving cell to utilize the one or more sub-bands, and transmitting the MWU signal for the one or more sub-bands in the serving cell.

In an additional aspect of the present disclosure, a method of wireless communication is provided. The method includes receiving a multi-band wake-up (MWU) signal for one or more sub-bands in a serving cell that includes a first user and a second user, the MWU signal including a first user identifier that identifies the first user as a targeted receiver of the MWU signal, decoding a payload of the MWU signal, and determining availability of the one or more sub-bands to the first user in the serving cell based on the payload of the MWU signal, a clear channel assessment (CCA) on the one or more sub-bands that are available to the first user being clear, the first user having priority over the second user in the serving cell to utilize the one or more sub-bands.

In one aspect of the present disclosure, an apparatus of wireless communication is provided. The apparatus includes means for determining a multi-band wake-up (MWU) signal that indicates availability of one or more sub-bands to a first user in a serving cell, a clear channel assessment (CCA) on the one or more sub-bands that are available to the first user being clear, the MWU signal including a first user identifier that identifies the first user as a targeted receiver of the MWU signal, the first user having priority over a second user in the serving cell to utilize the one or more sub-bands, and means for transmitting the MWU signal for the one or more sub-bands in the serving cell.

In an additional aspect of the present disclosure, an apparatus of wireless communication is provided. The apparatus includes means for receiving a multi-band wake-up (MWU) signal for one or more sub-bands in a serving cell that includes a first user and a second user, the MWU signal including a first user identifier that identifies the first user as a targeted receiver of the MWU signal, means for decoding a payload of the MWU signal, and means for determining availability of the one or more sub-bands to the first user in the serving cell based on the payload of the MWU signal, a clear channel assessment (CCA) on the one or more sub-bands that are available to the first user being clear, the first user having priority over the second user in the serving cell to utilize the one or more sub-bands.

In one aspect of the disclosure, a non-transitory computer-readable medium has program code recorded thereon. The program code further includes program code executable by a computer for causing the computer to receive a multi-band wake-up (MWU) signal for one or more sub-bands in a serving cell that includes a first user and a second user, the MWU signal including a first user identifier that identifies the first user as a targeted receiver of the MWU signal, decoding a payload of the MWU signal, and to determine availability of the one or more sub-bands to the first user in the serving cell based on the payload of the MWU signal, a clear channel assessment (CCA) on the one or more sub-bands that are available to the first user being clear, the first user having priority over the second user in the serving cell to utilize the one or more sub-bands.

In an additional aspect of the disclosure, a non-transitory computer-readable medium has program code recorded thereon. The program code further includes program code executable by a computer for causing the computer to determine a multi-band wake-up (MWU) signal that indicates availability of one or more sub-bands to a first user in a serving cell, a clear channel assessment (CCA) on the one or more sub-bands that are available to the first user being clear, the MWU signal including a first user identifier that identifies the first user as a targeted receiver of the MWU signal, the first user having priority over a second user in the serving cell to utilize the one or more sub-bands, and to transmit the MWU signal for the one or more sub-bands in the serving cell.

In one aspect of the disclosure, an apparatus configured for wireless communication is disclosed. The apparatus includes at least one processor, and a memory coupled to the processor. The processor is configured to determine a multi-band wake-up (MWU) signal that indicates availability of one or more sub-bands to a first user in a serving cell, a clear channel assessment (CCA) on the one or more sub-bands that are available to the first user being clear, the MWU signal including a first user identifier that identifies the first user as a targeted receiver of the MWU signal, the first user having priority over a second user in the serving cell to utilize the one or more sub-bands, and to transmit the MWU signal for the one or more sub-bands in the serving cell.

In an additional aspect of the disclosure, an apparatus configured for wireless communication is disclosed. The apparatus includes at least one processor, and a memory coupled to the processor. The processor is configured to determine a multi-band wake-up (MWU) signal that indicates availability of one or more sub-bands to a first user in a serving cell, a clear channel assessment (CCA) on the one or more sub-bands that are available to the first user being clear, the MWU signal including a first user identifier that identifies the first user as a targeted receiver of the MWU signal, the first user having priority over a second user in the serving cell to utilize the one or more sub-bands, and to transmit the MWU signal for the one or more sub-bands in the serving cell.

DETAILED DESCRIPTION

FIG. 1is a block diagram illustrating 5G network100including various base stations and UEs configured according to aspects of the present disclosure. The 5G network100includes a number of base stations105and other network entities. A base station may be a station that communicates with the UEs and may also be referred to as an evolved node B (eNB), a next generation eNB (gNB), an access point, and the like. Each base station105may provide communication coverage for a particular geographic area. In 3GPP, the term “cell” can refer to this particular geographic coverage area of a base station and/or a base station subsystem serving the coverage area, depending on the context in which the term is used.

The 5G network100may support synchronous or asynchronous operation. For synchronous operation, the base stations may have similar frame timing, and transmissions from different base stations may be approximately aligned in time. For asynchronous operation, the base stations may have different frame timing, and transmissions from different base stations may not be aligned in time.

The UEs115are dispersed throughout the wireless network100, and each UE may be stationary or mobile. A UE may also be referred to as a terminal, a mobile station, a subscriber unit, a station, or the like. A UE may be a cellular phone, a personal digital assistant (PDA), a wireless modem, a wireless communication device, a handheld device, a tablet computer, a laptop computer, a cordless phone, a wireless local loop (WLL) station, or the like. UEs115a-115dare examples of mobile smart phone-type devices accessing 5G network100A UE may also be a machine specifically configured for connected communication, including machine type communication (MTC), enhanced MTC (eMTC), narrowband IoT (NB-IoT) and the like. UEs115e-115kare examples of various machines configured for communication that access 5G network100. A UE may be able to communicate with any type of the base stations, whether macro base station, small cell, or the like. InFIG. 1, a lightning bolt (e.g., communication links) indicates wireless transmissions between a UE and a serving base station, which is a base station designated to serve the UE on the downlink and/or uplink, or desired transmission between base stations, and backhaul transmissions between base stations.

FIG. 2shows a block diagram of a design of a base station105and a UE115, which may be one of the base station and one of the UEs inFIG. 1. At the base station105, a transmit processor220may receive data from a data source212and control information from a controller/processor240. The control information may be for the PBCH, PCFICH, PHICH, PDCCH, EPDCCH, MPDCCH etc. The data may be for the PDSCH, etc. The transmit processor220may process (e.g., encode and symbol map) the data and control information to obtain data symbols and control symbols, respectively. The transmit processor220may also generate reference symbols, e.g., for the PSS, SSS, and cell-specific reference signal. A transmit (TX) multiple-input multiple-output (MIMO) processor230may perform spatial processing (e.g., precoding) on the data symbols, the control symbols, and/or the reference symbols, if applicable, and may provide output symbol streams to the modulators (MODs)232athrough232t. Each modulator232may process a respective output symbol stream (e.g., for OFDM, etc.) to obtain an output sample stream. Each modulator232may further process (e.g., convert to analog, amplify, filter, and upconvert) the output sample stream to obtain a downlink signal. Downlink signals from modulators232athrough232tmay be transmitted via the antennas234athrough234t, respectively.

At the UE115, the antennas252athrough252rmay receive the downlink signals from the base station105and may provide received signals to the demodulators (DEMODs)254athrough254r, respectively. Each demodulator254may condition (e.g., filter, amplify, downconvert, and digitize) a respective received signal to obtain input samples. Each demodulator254may further process the input samples (e.g., for OFDM, etc.) to obtain received symbols. A MIMO detector256may obtain received symbols from all the demodulators254athrough254r, perform MIMO detection on the received symbols if applicable, and provide detected symbols. A receive processor258may process (e.g., demodulate, deinterleave, and decode) the detected symbols, provide decoded data for the UE115to a data sink260, and provide decoded control information to a controller/processor280.

On the uplink, at the UE115, a transmit processor264may receive and process data (e.g., for the PUSCH) from a data source262and control information (e.g., for the PUCCH) from the controller/processor280. The transmit processor264may also generate reference symbols for a reference signal. The symbols from the transmit processor264may be precoded by a TX MIMO processor266if applicable, further processed by the modulators254athrough254r(e.g., for SC-FDM, etc.), and transmitted to the base station105. At the base station105, the uplink signals from the UE115may be received by the antennas234, processed by the demodulators232, detected by a MIMO detector236if applicable, and further processed by a receive processor238to obtain decoded data and control information sent by the UE115. The processor238may provide the decoded data to a data sink239and the decoded control information to the controller/processor240.

The controllers/processors240and280may direct the operation at the base station105and the UE115, respectively. The controller/processor240and/or other processors and modules at the base station105may perform or direct the execution of various processes for the techniques described herein. The controllers/processor280and/or other processors and modules at the UE115may also perform or direct the execution of the functional blocks illustrated inFIGS. 5, 6, and 7, and/or other processes for the techniques described herein. The memories242and282may store data and program codes for the base station105and the UE115, respectively. A scheduler244may schedule UEs for data transmission on the downlink and/or uplink.

Wireless communications systems operated by different network operating entities (e.g., network operators) may share spectrum. In some instances, a network operating entity may be configured to use an entirety of a designated shared spectrum for at least a period of time before another network operating entity uses the entirety of the designated shared spectrum for a different period of time. Thus, in order to allow network operating entities use of the full designated shared spectrum, and in order to mitigate interfering communications between the different network operating entities, certain resources (e.g., time) may be partitioned and allocated to the different network operating entities for certain types of communication.

For example, a network operating entity may be allocated certain time resources reserved for exclusive communication by the network operating entity using the entirety of the shared spectrum. The network operating entity may also be allocated other time resources where the entity is given priority over other network operating entities to communicate using the shared spectrum. These time resources, prioritized for use by the network operating entity, may be utilized by other network operating entities on an opportunistic basis if the prioritized network operating entity does not utilize the resources. Additional time resources may be allocated for any network operator to use on an opportunistic basis.

Access to the shared spectrum and the arbitration of time resources among different network operating entities may be centrally controlled by a separate entity, autonomously determined by a predefined arbitration scheme, or dynamically determined based on interactions between wireless nodes of the network operators.

Use of a medium-sensing procedure to contend for access to an unlicensed shared spectrum may result in communication inefficiencies. This may be particularly evident when multiple network operating entities (e.g., network operators) are attempting to access a shared resource. In 5G network100, base stations105and UEs115may be operated by the same or different network operating entities. In some examples, an individual base station105or UE115may be operated by more than one network operating entity. In other examples, each base station105and UE115may be operated by a single network operating entity. Requiring each base station105and UE115of different network operating entities to contend for shared resources may result in increased signaling overhead and communication latency.

FIG. 3illustrates an example of a timing diagram300for coordinated resource partitioning. The timing diagram300includes a superframe305, which may represent a fixed duration of time (e.g., 20 ms). Superframe305may be repeated for a given communication session and may be used by a wireless system such as 5G network100described with reference toFIG. 1. The superframe305may be divided into intervals such as an acquisition interval (A-INT)310and an arbitration interval315. As described in more detail below, the A-INT310and arbitration interval315may be subdivided into sub-intervals, designated for certain resource types, and allocated to different network operating entities to facilitate coordinated communications between the different network operating entities. For example, the arbitration interval315may be divided into a plurality of sub-intervals320. Also, the superframe305may be further divided into a plurality of subframes325with a fixed duration (e.g., 1 ms). While timing diagram300illustrates three different network operating entities (e.g., Operator A, Operator B, Operator C), the number of network operating entities using the superframe305for coordinated communications may be greater than or fewer than the number illustrated in timing diagram300.

The A-INT310may be a dedicated interval of the superframe305that is reserved for exclusive communications by the network operating entities. In some examples, each network operating entity may be allocated certain resources within the A-INT310for exclusive communications. For example, resources330-amay be reserved for exclusive communications by Operator A, such as through base station105a, resources330-bmay be reserved for exclusive communications by Operator B, such as through base station105b, and resources330-cmay be reserved for exclusive communications by Operator C, such as through base station105c. Since the resources330-aare reserved for exclusive communications by Operator A, neither Operator B nor Operator C can communicate during resources330-a, even if Operator A chooses not to communicate during those resources. That is, access to exclusive resources is limited to the designated network operator. Similar restrictions apply to resources330-bfor Operator B and resources330-cfor Operator C. The wireless nodes of Operator A (e.g., UEs115or base stations105) may communicate any information desired during their exclusive resources330-a, such as control information or data.

When communicating over an exclusive resource, a network operating entity does not need to perform any medium sensing procedures (e.g., listen-before-talk (LBT) or clear channel assessment (CCA)) because the network operating entity knows that the resources are reserved. Because only the designated network operating entity may communicate over exclusive resources, there may be a reduced likelihood of interfering communications as compared to relying on medium sensing techniques alone (e.g., no hidden node problem). In some examples, the A-INT310is used to transmit control information, such as synchronization signals (e.g., SYNC signals), system information (e.g., system information blocks (SIBs)), paging information (e.g., physical broadcast channel (PBCH) messages), or random access information (e.g., random access channel (RACH) signals). In some examples, all of the wireless nodes associated with a network operating entity may transmit at the same time during their exclusive resources.

In some examples, resources may be classified as prioritized for certain network operating entities. Resources that are assigned with priority for a certain network operating entity may be referred to as a guaranteed interval (G-INT) for that network operating entity. The interval of resources used by the network operating entity during the G-INT may be referred to as a prioritized sub-interval. For example, resources335-amay be prioritized for use by Operator A and may therefore be referred to as a G-INT for Operator A (e.g., G-INT-OpA). Similarly, resources335-bmay be prioritized for Operator B, resources335-cmay be prioritized for Operator C, resources335-dmay be prioritized for Operator A, resources335-emay be prioritized for Operator B, and resources335-fmay be prioritized for operator C.

The various G-INT resources illustrated inFIG. 3appear to be staggered to illustrate their association with their respective network operating entities, but these resources may all be on the same frequency bandwidth. Thus, if viewed along a time-frequency grid, the G-INT resources may appear as a contiguous line within the superframe305. This partitioning of data may be an example of time division multiplexing (TDM). Also, when resources appear in the same sub-interval (e.g., resources340-aand resources335-b), these resources represent the same time resources with respect to the superframe305(e.g., the resources occupy the same sub-interval320), but the resources are separately designated to illustrate that the same time resources can be classified differently for different operators.

When resources are assigned with priority for a certain network operating entity (e.g., a G-INT), that network operating entity may communicate using those resources without having to wait or perform any medium sensing procedures (e.g., LBT). For example, the wireless nodes of Operator A are free to communicate any data or control information during resources335-awithout interference from the wireless nodes of Operator B or Operator C.

A network operating entity may additionally signal to another operator that it intends to use a particular G-INT. For example, referring to resources335-a, Operator A may signal to Operator B and Operator C that it intends to use resources335-a. Such signaling may be referred to as an activity indication. Moreover, since Operator A has priority over resources335-a, Operator A may be considered as a higher priority operator than both Operator B and Operator C. However, as discussed above, Operator A does not have to send signaling to the other network operating entities to ensure interference-free transmission during resources335-abecause the resources335-aare assigned with priority to Operator A.

Similarly, a network operating entity may signal to another network operating entity that it intends not to use a particular G-INT. This signaling may also be referred to as an activity indication. For example, referring to resources335-b, Operator B may signal to Operator A and Operator C that it intends not to use the resources335-bfor communication, even though the resources are assigned with priority to Operator B. With reference to resources335-b, Operator B may be considered a higher priority network operating entity than Operator A and Operator C. In such cases, Operators A and C may attempt to use resources of sub-interval320on an opportunistic basis. Thus, from the perspective of Operator A, the sub-interval320that contains resources335-bmay be considered an opportunistic interval (O-INT) for Operator A (e.g., O-INT-OpA). For illustrative purposes, resources340-amay represent the O-INT for Operator A. Also, from the perspective of Operator C, the same sub-interval320may represent an O-INT for Operator C with corresponding resources340-b. Resources340-a,335-b, and340-ball represent the same time resources (e.g., a particular sub-interval320), but are identified separately to signify that the same resources may be considered as a G-INT for some network operating entities and yet as an O-INT for others.

To utilize resources on an opportunistic basis, Operator A and Operator C may perform medium-sensing procedures to check for ongoing communications on multiple sub-bands before transmitting their own data. For example, if Operator B decides not to use resources335-b(e.g., G-INT-OpB), then Operator A may use those same resources (e.g., represented by resources340-a) by first checking the channel for interference (e.g., LBT) and then transmitting data if the channel was determined to be clear. Similarly, if Operator C wanted to access resources on an opportunistic basis during sub-interval320(e.g., use an O-INT represented by resources340-b) in response to an indication that Operator B was not going to use its G-INT, Operator C may perform a medium sensing procedure and access the resources if available. In some cases, two operators (e.g., Operator A and Operator C) may attempt to access the same resources, in which case the operators may employ contention-based procedures to avoid interfering communications. The operators may also have sub-priorities assigned to them designed to determine which operator may gain access to resources if more than one operator is attempting access simultaneously.

In some examples, a network operating entity may intend not to use a particular G-INT assigned to it, but may not send out an activity indication that conveys the intent not to use the resources. In such cases, for a particular sub-interval320, lower priority operating entities may be configured to monitor the channel to determine whether a higher priority operating entity is using the resources. If a lower priority operating entity determines through LBT or similar method that a higher priority operating entity is not going to use its G-INT resources, then the lower priority operating entities may attempt to access the resources on an opportunistic basis as described above.

In some examples, access to a G-INT or O-INT may be preceded by a reservation signal (e.g., request-to-send (RTS)/clear-to-send (CTS)), and the contention window (CW) may be randomly chosen between one and the total number of operating entities.

In some examples, an operating entity may employ or be compatible with coordinated multipoint (CoMP) communications. For example an operating entity may employ CoMP and dynamic time division duplex (TDD) in a G-INT and opportunistic CoMP in an O-INT as needed.

In the example illustrated inFIG. 3, each sub-interval320includes a G-INT for one of Operator A, B, or C. However, in some cases, one or more sub-intervals320may include resources that are neither reserved for exclusive use nor reserved for prioritized use (e.g., unassigned resources). Such unassigned resources may be considered an O-INT for any network operating entity, and may be accessed on an opportunistic basis as described above.

In some examples, each subframe325may contain 14 symbols (e.g., 250-μs for 60 kHz tone spacing). These subframes325may be standalone, self-contained Interval-Cs (ITCs) or the subframes325may be a part of a long ITC. An ITC may be a self-contained transmission starting with a downlink transmission and ending with a uplink transmission. In some embodiments, an ITC may contain one or more subframes325operating contiguously upon medium occupation. In some cases, there may be a maximum of eight network operators in an A-INT310(e.g., with duration of 2 ms) assuming a 250-μs transmission opportunity.

Although three operators are illustrated inFIG. 3, it should be understood that fewer or more network operating entities may be configured to operate in a coordinated manner as described above. In some cases, the location of the G-INT, O-INT, or A-INT within superframe305for each operator is determined autonomously based on the number of network operating entities active in a system. For example, if there is only one network operating entity, each sub-interval320may be occupied by a G-INT for that single network operating entity, or the sub-intervals320may alternate between G-INTs for that network operating entity and O-INTs to allow other network operating entities to enter. If there are two network operating entities, the sub-intervals320may alternate between G-INTs for the first network operating entity and G-INTs for the second network operating entity. If there are three network operating entities, the G-INT and O-INTs for each network operating entity may be designed as illustrated inFIG. 3. If there are four network operating entities, the first four sub-intervals320may include consecutive G-INTs for the four network operating entities and the remaining two sub-intervals320may contain O-INTs. Similarly, if there are five network operating entities, the first five sub-intervals320may contain consecutive G-INTs for the five network operating entities and the remaining sub-interval320may contain an O-INT. If there are six network operating entities, all six sub-intervals320may include consecutive G-INTs for each network operating entity. It should be understood that these examples are for illustrative purposes only and that other autonomously determined interval allocations may be used.

It should be understood that the coordination framework described with reference toFIG. 3is for illustration purposes only. For example, the duration of superframe305may be more or less than 20 ms. Also, the number, duration, and location of sub-intervals320and subframes325may differ from the configuration illustrated. Also, the types of resource designations (e.g., exclusive, prioritized, unassigned) may differ or include more or less sub-designations.

In NR networks, a shared radio frequency spectrum band, which may include licensed or unlicensed frequency spectrum, can be divided into multiple non-overlapping sub-bands. The multiple sub-bands can belong to different carrier frequencies, which can be contiguous, non-contiguous, or a hybrid of thereof. In an unlicensed frequency portion of the shared radio frequency spectrum band, a network node, such as a base station, a gNB, a UE, or a wireless node in the networks, may access one or more sub-bands on an opportunistic basis by performing medium sensing procedures. For example, a network node may perform a CCA in order to determine whether certain sub-bands or channels are available. The medium sensing procedures may mitigate interferences between a desirable user and an aggressor.

A desirable user may be a user that is authorized to access and utilize certain sub-bands; and an aggressor may be a user that is not authorized to access and utilize the sub-bands reserved for the desirable user or that is not given priority to access and utilize such sub-bands. Therefore, a desirable user may be also called as a prioritized user. However, a network node may not be defined as a desirable user or an aggressor permanently. For example, a network node may be a desirable user in one transmission opportunity (TxOP) utilizing certain sub-bands, but may be an aggressor in another TxOP utilizing other sub-bands. As a further example, a network node may be a desirable user in its own serving cell, but may be an aggressor for another cell.

Both a desirable user and an aggressor may benefit from an early indication of multi-band medium sharing status. They can react accordingly and save resources and power. For instance, upon knowing that certain sub-bands are reserved for a desirable user, an aggressor may refrain from transmitting signals on such sub-bands to mitigate interference. As a further instance, upon knowing availability of certain sub-bands, a desirable user may reduce its search space of PDCCH based on the knowledge of available sub-bands. Therefore, the desirable user can save power and reduce processing complexity and latency, since it does not need to search for DL/UL control information on unavailable sub-bands.

Various aspects of the present disclosure provide enhancement for early medium sharing status signaling and indication. The signaling and indication of multi-band medium sharing status, such as availability of sub-bands in unlicensed spectrum, may be different for different users. A multi-band wake-up (MWU) signal may target a desirable user and indicate availability of one or more sub-bands. On the other hand, a multi-band channel reservation (MCR) signal may target an aggressor and indicate an occupancy status of one or more sub-bands that are reserved for a desirable user. MWU and MCR signals may be scrambled with different radio network temporary identifiers (RNTIs) in order to target different users. MWU and MCR signals may be multiplexed in frequency domain and fully or partially overlap in time domain.

Further aspects of the present disclosure provide details regarding how to determine a waveform for the multiplexed MWU and MCR signals, and how to indicate availability of sub-bands in the MWU signals. MWU and MCR signals may be not needed in licensed spectrum as the resources in licensed spectrum are not allocated on an opportunistic basis.

FIG. 4is a block diagram illustrating details of a wireless communication system. In serving cell400, base station402may transmit MWU signals, MCR signals, or multiplexed MWU and MCR signals to UEs404a-fbefore transmitting regular control information and data traffic. Base station402may be an eNB, a gNB, an access point, or the like and have the same or similar configuration as the configuration of base station105and base station1000inFIGS. 1, 2, 3, and 10. UEs404a-fmay be a terminal, a mobile station, a mobile device, a subscriber unit, a station, or the like and have the same or similar configuration of UE115and UE1100inFIGS. 1, 2, 3, and 11. In some sub-bands, UEs404a-cmay be desirable users and UEs404d-fmay be aggressors in serving cell400. In some sub-bands, UEs404d-fmay be desirable users and UEs404a-cmay be aggressors in serving cell400. Desirable users may be given priority over aggressors to communicate using certain shared sub-bands.

FIG. 5is a functional block diagram illustrating exemplary blocks executed to implement procedures for processing MWU and MCR signals, respectively. InFIG. 5, a desirable user may follow procedure502to process frequency-multiplexed MWU and MCR signals504or MWU signal524; and an aggressor may follow procedure500to process frequency-multiplexed MWU and MCR signals504or MCR signal522. Procedures500and502may be performed for a TxOP in one or more LBT phases periodically or dynamically according to radio resource control (RRC). The time duration of the TxOP may be pre-configured by RRC and known by both a base station and users. The schedule of wake-up, at which users may enter a connected mode from a power-saving mode to monitor MWU signals, MCR signals, or control information, may be determined based on the TxOP configuration. In a preferred case, procedures500and502may be performed for a TxOP in each LBT phase on each sub-band.

In procedure502, at block514, a desirable user may monitor one or more MWU signals. The MWU signal may be transmitted or broadcast alone, such as MWU signal524, or multiplexed with a MCR signal in frequency domain and transmitted or broadcast along with the MCR signal, such as multiplexed MWU and MCR signals504. The MWU signal may be scrambled with a radio network temporary identifier (RNTI) of the desirable user to target the desirable user. The MCR signal may be scrambled with an RNTI of an aggressor to target the aggressor. Accordingly, the desirable user may be able to receive and process the MWU signal and disregard the MCR signal that does not target itself. RNTIs of the desirable users and aggressors may be pre-configured by an upper layer and known by both a base station and users in a serving cell in advance via a hand-shake procedure or the like.

At block516, the desirable user may decode a payload of the MWU signal in order to retrieve information regarding availability of one or more sub-bands in a serving cell that the desirable user belongs. The one or more sub-bands that pass a CCA check may be available to the desirable user. At block518, the desirable user may adjust PDCCH search space according to the availability of the one or more sub-bands. For example, the desirable user may avoid from searching for DL/UL control information in resources on unavailable sub-bands. At block520, the desirable user may receive or transmit regular DL/UL control information and data traffic on the available sub-bands. Procedure502may repeat for a TxOP in a next LBT phase.

In procedure500, at block506, an aggressor may monitor one or more MCR signals. The MCR signals may be transmitted or broadcast alone, such as MCR signal522, or multiplexed with a MWU signal in frequency domain and transmitted or broadcast along with the MWU signal, such as multiplexed MWU and MCR signals504. The MCR signal may be scrambled with a radio network temporary identifier (RNTI) of the aggressor to target the aggressor. Accordingly, the aggressor may be able to receive and process the MCR signal and disregard the MWU signal that does not target itself.

At block508, the aggressor may decode a payload of the MCR signal in order to retrieve information regarding an occupancy status of one or more sub-bands by a desirable user. At block510, the aggressor may yield to the desirable user and enter a power-saving mode, such as a sleep mode, according to the information regarding the occupancy status of the one or more sub-bands. In the power-saving mode, the aggressor may refrain from utilizing the sub-bands reserved for the desirable user. At block512, the aggressor may wake up from the power-saving mode in order to monitor MCR signals before the beginning of a next LBT phase. In some cases, the aggressor may monitor MCR signals from a base station of a serving cell of a desirable user as well as MWU signals from a base station of its own serving cell. Procedure500may repeat for a TxOP in a next LBT phase.

In some aspects of the present disclosure, a desirable user that performs procedure502in a TxOP on one sub-band may perform procedure500in another TxOP on another sub-band. Also, an aggressor that performs procedure500in a TxOP on one sub-band may perform procedure502in another TxOP on anther sub-band. A user may perform different procedures based on its sub-band specific category (either a desirable user or an aggressor).

FIG. 6is a functional block diagram illustrating exemplary blocks executed to implement one aspect of the present disclosure. The example blocks may be implemented by a desirable user, such as UE115or UE1100inFIGS. 1, 2, 3, and 11. At block600, a MWU signal for one or more sub-bands in a serving cell that includes a first user and a second user may be received. The first user may be a desirable user. The second user may be an aggressor. The MWU signal may include a first user identifier that identifies the first user as a targeted receiver of the MWU signal. For example, the first user identifier may be a RNTI of the desirable user. At block602, a payload of the MWU signal may be decoded. At block604, availability of the one or more sub-bands to the first user in the serving cell may be determined based on the payload of the MWU signal. The one or more sub-bands that are indicated to be available to the first user may have a clear CCA result. The first user may have priority over the second user in the serving cell to utilize the available sub-bands.

In some aspects of the present disclosure, a desirable user may reduce PDCCH search space based on the availability of the one or more sub-bands. In another aspect of the present disclosure, the desirable user may also receive a MCR signal that is multiplexed with the MWU signal in frequency domain. However, the desirable user may disregard the received MCR signal as the MCR signal may only target an aggressor. After receiving the MWU signal or the multiplexed MWU and MCR signals, the desirable user may receive regular control information and/or data traffic on the available sub-bands. In an additional aspect of the present disclosure, the desirable user may receive the MWU signal or multiplexed MWU and MCR signals on each of the available sub-bands.

FIG. 7is a functional block diagram illustrating exemplary blocks executed to implement one aspect of the present disclosure. The example blocks may be implemented by a base station, such as base station105or base station1000inFIGS. 1, 2, 3, and 10. At block700, a MWU signal may be determined. The MWU signal may be determined to indicate availability of one or more sub-bands to a first user in a serving cell. A CCA on the one or more sub-bands that are available to the first user may be clear. The MWU signal may include a first user identifier that identifies the first user as a targeted receiver of the MWU signal. The first user may have priority over a second user in the serving cell to utilize the one or more sub-bands. For example, the first user may be a desirable user and the second user may be an aggressor. The first user identifier may be a RNTI of the desirable user. At block702, the MWU signal may be transmitted for the one or more sub-bands in the serving cell.

In some aspects of the present disclosure, the base station may also transmit a MCR signal that is multiplexed with the MWU signal in frequency domain. The MCR signal may target an aggressor so that may be disregard by a desirable user. After transmitting the MWU signal or the multiplexed MWU and MCR signals, the base station may further transmit regular control information and/or data traffic on the available sub-band. In an additional aspect of the present disclosure, the base station may transmit the MWU signal or multiplexed MWU and MCR signals on each of the available sub-bands. In the case that the MCR signal is multiplexed with the MWU signal, the transmit power of both MCR and MWU signals may be considered together in order to be compliant with regulatory constraints.

MWU and MCR signals may have different configuration. A MWU signal that targets a desirable user may be synchronized with the transmission timeline of the desirable user. Therefore, an extra synchronization signal or an acquisition signal may be optional. However, a MCR signal that targets an aggressor may not be synchronized with the transmission timeline of the desirable user. As such, the MCR signal may need an additional synchronization or acquisition signal to establish timing/frequency synchronization. For example, the MCR signal may have a CR preamble in front of its payload for such purpose.

FIG. 8illustrates a block diagram illustrating configuration of multiplexed MWU and MCR signals according to one aspect of the present disclosure. MCR signal800may be multiplexed with MWU signal802in frequency domain. MCR signal800may partially overlap with MWU signal802in time domain. The frequency-multiplexing of MCR and MWU signals may be beneficial to reduce overall overhead of signaling. MCR signal800may include CR preamble804and payload808. CR preamble804may have time duration r826. Payload808may have time duration τsym828. MWU signal802may include payload814. Payload814may have time duration τsym828.

In unlicensed spectrum, a base station may need time to obtain resources to transmit signals, information, or data traffic after passing a CCA check. Therefore, there may be time gap TG824between CCA clearance at time838and a start of transmission of an OFDM symbol at time840. In order to determine a waveform for frequency-multiplexed MWU and MCR signals, this time gap, which may vary in different conditions, may be considered to construct dynamic cyclic prefixes806and812preceding OFDM symbol836, in which payloads808and814are transmitted. For example, time duration τDCP832of dynamic cyclic prefixes806and812may be the difference between time gap TG824and CR preamble804and calculated by the base station. Dynamic cyclic prefix806may be copied from by the tail part of OFDM symbol810. Dynamic cyclic prefix812may be copied from the tail part of OFDM symbol816.

In some aspects of the present disclosure, time duration τDCP832of dynamic cyclic prefixes806and812may be shorter than a time duration of a normal cyclic prefix, such as τNCP834of normal cyclic prefix818of OFDM symbol830. In OFDM symbol830, the payload of regular control information or data traffic820is transmitted. Normal cyclic prefix818may be copied from the tail part of OFDM symbol822. In order to avoid interference between OFDM symbols and compensate the time gap TG824, time duration τDCP832of dynamic cyclic prefixes806and812may be longer than time duration τNCP834of normal cyclic prefix818.

FIG. 9illustrates a block diagram illustrating configuration of multiplexed MWU and MCR signals on multiple sub-bands according to one aspect of the present disclosure. In TxOP940, MWU signals902and922and MCR signals900and920may be transmitted on multiple sub-bands, such as sub-bands918and938. MWU signals902and922may be multiplexed with MCR signals900and920on sub-bands918and938, respectively. On sub-band918, MWU signal902may have dynamic cyclic prefix910and payload912; and MCR signal900may have CR preamble904, dynamic cyclic prefix906, and payload908. After transmissions of MCR signal900and MWU signal902, the payload of regular control information or data traffic916and its normal cyclic prefix914may be transmitted. On sub-band938, MWU signal922may have dynamic cyclic prefix930and payload932; and MCR signal920may have CR preamble924, dynamic cyclic prefix926, and payload928. After transmissions of MCR signal920and MWU signal922, the payload of regular control information or data traffic936and its normal cyclic prefix934may be transmitted.

Availability of one or more sub-bands may be indicated in a MWU signal in various ways. For example, a MWU signal may include sub-band size information of a current sub-band on which the MWU signal is transmitted. This option may cause a small overhead and low diversity gain. However, this MWU signal may not be used to perform integrity check because it does not include information regarding availability of other sub-bands. As a further example, a MWU signal may include information regarding availability of its own sub-band and other sub-bands. This option may cause a higher overhead but improve reliability because integrity check can be performed based on availability information across sub-bands. For instance, in addition to sub-band size of its own sub-band, the MWU signal may also carry a bitmap of other available sub-bands to indicate availability of other sub-bands. Moreover, a MWU signal may include information regarding availability of a cluster of sub-bands, which may be a subset of all the sub-bands. The information may include a cluster size, a cluster index, an indicator indicating a sub-band location in the cluster of sub-bands, and a bitmap of clustered sub-bands. Further, a MWU signal may include information regarding availability of contiguous sub-bands. The information may include a length of continuous sub-bands, a location of a start of the contiguous sub-bands, and a sub-band size of a sub-band within the contiguous sub-bands.

In addition, a MWU signal may be designed for a carrier aggregation (CA) scenario. The MWU signal may include at least one component carrier (CC) index and at least one sub-band index. For example, the MWU signal may indicate that CC1 (the first CC) on 2 GHz band and CC3 (the third CC) on 6 GHz band are available. Also, the MWU signal may further indicate that certain sub-bands on CC1 and CC3 are available. For instance, the MWU signal may indicate that CC1 has 80 MHz bandwidth but only the first and the fourth 20 MHz bands are available for transmissions (assuming 80 MHz bandwidth is divided into four portions).

A base station may perform rate matching, interleaving, channel coding, modulation, and control channel resource set (Coreset) mapping on the payload of a MWU signal in order to map the MWU signal onto resource elements, and to configure the MWU search space and determine an aggregation level for the MWU signal. The format in the payload of the MWU signal may be similar to downlink control information (DCI). Therefore, in some cases, the base station may reuse the design of NR PDCCH Coreset. The MWU Coreset may include common search space. In order to avoid decoding or detecting mistakes, a MWU signal may carry limited information, such as basic information indicating the availability of sub-bands, in its payload to increase reliability and leave other detailed information to be transmitted in regular control channel or data channel.

In some aspects of the present disclosure, a channel state information-reference signal (CSI-RS) may be multiplexed with a MWU signal. Accordingly, a desirable user may perform CSI measurement and interference measurement sooner. In another aspect of the present disclosure, a pointer may be added into a MWU signal to point to different search space for users with different capabilities regarding CA. For example, a pointer may be added into a MWU signal to indicate a low-end UE without the support of CA functionality to monitor PDCCH on a given carrier frequency. As a further example, another pointer may be added into a MWU signal to indicate a relatively high-end UE with the CA functionality to monitor PDCCH on multiple carrier frequencies.

FIG. 10is a block diagram of base station1000in a communication network according to one aspect of the present disclosure. Base station1000may have the same or similar configuration as the configuration of base station105inFIGS. 1, 2, and 3. Base station1000may include controller/processor240to perform or direct the execution of various processes or program codes stored in memory242. Base station1000may further include wireless radios1002to process uplink or downlink signals received from antennas234a-t. Memory242may store program codes for execution of MWU signal determining logic1004and signal transmitting logic1010. MWU signal determining logic1004may be used to determine a MWU signal that indicates availability of one or more sub-bands to a first user in a serving cell. Signal transmitting logic1010may be used to transmit the MWU signal for the one or more sub-bands in the serving cell. A CCA on the one or more sub-bands that are available to the first user may be clear. The MWU signal may include a first user identifier that identifies the first user as a targeted receiver of the MWU signal. The first user may have priority over a second user in the serving cell to utilize the one or more sub-bands. Memory242may further store program codes for execution of MCR signal determining logic1006and signal multiplexer1008. MCR signal determining logic1006may be used to determine a MCR signal that indicates an occupancy status of at least one of the one or more sub-bands by the first user. The MCR signal may include a second user identifier that identifies the second user a s target receiver of the MCR signal. Signal multiplexer1008may be used to multiple the MWU signal with the MCR signal in frequency domain. Signal transmitting logic1010may be also used to transmit the multiplexed MWU and MCR signals.

FIG. 11is a block diagram of UE1100in a communication network according to one aspect of the present disclosure. UE1100may have the same or similar configuration as the configuration of UE115inFIGS. 1, 2, and 3. UE1100may include controller/processor280to perform or direct the execution of various processes or program codes stored in memory282. UE1100may further include wireless radios1102to process uplink or downlink signals received from antennas252a-r. Memory282may store program codes for execution of signal receiving logic1104, signal decoding logic1106, and sub-band availability determining logic1108. Signal receiving logic1104may be used to receive a MWU signal for one or more sub-band in a serving cell that includes a first user and a second user. The first user may be UE1100and the second user may be an aggressor in the serving cell. The MWU signal may include a first user identifier that identifies the first user as a targeted receiver of the MWU signal. Signal decoding logic1106may be used to decode a payload of the MWU signal. Sub-band availability determining logic1108may be used to determine availability of the one or more sub-bands to the first user in the serving cell based on the payload of the MWU signal. A CCA on the one or more sub-bands that are availability to the first user may be clear. The first user may have priority over the second user in the serving cell to utilize the one or more sub-bands. Memory282may further store program codes for execution of search space determining logic1110. Search space determining logic1110may be used to adjust PDCCH search space based on the availability of the one or more sub-bands. The adjusting may include increase or decrease of the PDCCH search space. Signal receiving logic1104may be further used to receive a MWU signal that is multiplexed with a MCR signal in frequency domain. The MCR signal may indicate an occupancy status of at least one of the one or more sub-bands by the first user and includes a second user identifier identifying the second user as a targeted receiver of the MCR signal.