MECHANISMS FOR USER EQUIPMENT BEAM PAIRING ON SIDELINK COMMUNICATION

Some aspects of this disclosure relate to apparatuses and methods for implementing a beam pairing procedure between a transmission UE and a receiver UE. The transmission UE and the receiver UE can configure a set of beam patterns to be used in the beam pairing procedure. The set of beam patterns can include one or more transmission beams of the UE, and one or more receiving beams of the receiver UE. The transmission UE can transmit one or more sidelink reference signals to the receiver UE, and the receiver UE can perform signal strength measurements of the one or more sidelink reference signals. Based on the signal strength measurements, either the transmission UE or the receiver UE can make the selection of the transmission beam and the corresponding receiving beam for the beam pairing procedure.

BACKGROUND

Field

The described aspects generally relate to managing user equipment beam pairing on sidelink communication in a wireless communication system.

Related Art

A user equipment (UE) communicates with a base station (for example, an evolved Node B (eNB), a next generation node B (gNB), or other base station) in a wireless communication network or system. In addition, device-to-device (D2D) or sidelink communication among UEs is becoming more and more important for information exchange in wireless communication systems. Sidelink communication enables direct communication between proximate devices, e.g., multiple UEs, without going through the base station, leading to lower latency for communication among UEs. However, there are various issues to be resolved for sidelink communication among UEs in a wireless communication system.

SUMMARY

Some aspects of this disclosure relate to apparatuses and methods for implementing device-to-device (D2D) or sidelink communications among multiple user equipments (UEs) in wireless communication systems, e.g., a wireless communication system based on 3rd Generation Partnership Project (3GPP) release 16 (Rel-16), release 17 (Rel-17), or others. For example, systems and methods are provided implementing designs for New Radio (NR) wireless systems.

Some aspects of this disclosure relate to a UE. The UE, which may be a transmission UE, includes a transceiver and a processor communicatively coupled to the transceiver. The transceiver is configured to wirelessly communicate through an interface for sidelink communication with one or more UEs including a receiver UE. The processor configures a set of beam patterns to be used in a beam pairing procedure between the transmission UE and the receiver UE. The set of beam patterns can include one or more transmission beams of the UE, and one or more receiving beams of the receiver UE.

The processor can further be configured to transmit, using one or more beam patterns of the set of beam patterns, one or more sidelink reference signals to the receiver UE, and receive a message from the receiver UE. In some examples, the one or more sidelink reference signals are carried using a physical sidelink shared channel (PSSCH) that carries data information. The message may contain information related to signal strength measurements on the one or more beam patterns based on the one or more sidelink reference signals. Based on the received message, the processor can further be configured to determine a selected transmission beam selected from the one or more transmission beams of the UE for signal transmissions from the UE to the receiver UE. Afterwards, the processor is further configured to transmit data from the UE to the receiver UE using the selected transmission beam. In some examples, the UE can further be configured to receive a beam pairing request from the receiver UE before transmitting the one or more sidelink reference signals to the receiver UE.

In some examples, the one or more sidelink reference signals includes a sidelink (SL) channel state information reference signal (CSR-RS), and the signal strength measurements performed on the one or more beam patterns based on the one or more sidelink reference signals include a Reference Signal Receive Power (RSRP) measurement, a Reference Signal Received Quality (RSRQ), or a Signal to Interference & Noise Ratio (SINR).

In some examples, the message received from the receiver UE contains an identifier of the selected transmission beam selected by the receiver UE. In some other examples, the message received from the receiver UE contains the information related to the signal strength measurements on the one or more beam patterns based on the one or more sidelink reference signals. To determine the selected transmission beam, the processor is configured to select the selected transmission beam of the UE and a related receiving beam of the receiver UE based on the information related to the signal strength measurements on the one or more beam patterns based on the one or more sidelink reference signals. Afterwards, the processor is configured to transmit an indication to the receiver UE to indicate the selected transmission beam and the related receiving beam of the receiver UE. The indication to indicate the selected transmission beam and the related receiving beam includes a quasi-co-location (QCL) indication.

Some aspects of this disclosure relate to a UE and a method performed by a UE.

The UE, which may be a receiver UE, includes a transceiver and a processor communicatively coupled to the transceiver. The method performed by the receiver UE may include configuring a set of beam patterns to be used in a beam pairing procedure, where the set of beam patterns includes one or more receiving beams of the UE, and one or more transmission beams of a transmission UE. The method may further include receiving, using one or more beam patterns of the set of beam patterns, one or more sidelink reference signals from the transmission UE, where the one or more sidelink reference signals may be carried by a PSSCH that carries data information. Afterwards, the method can include performing signal strength measurements of the one or more sidelink reference signals.

In some examples, the one or more sidelink reference signals includes a sidelink (SL) channel state information reference signal (CSR-RS), and the signal strength measurements of the one or more sidelink reference signals include a Reference Signal Receive Power (RSRP) measurement, a Reference Signal Received Quality (RSRQ), or a Signal to Interference & Noise Ratio (SINR).

In some examples, the method may further include transmitting a message to the transmission UE, where the message may contain information related to the signal strength measurements of the one or more sidelink reference signals. In some examples, the message may be transmitted by a physical sidelink feedback channel (PSFCH). The method may further include determining a selected receiving beam selected from the one or more receiving beams of the UE for receiving signal transmissions from the transmission UE.

In some examples, the method may further include determining a selected transmission beam selected from the one or more transmission beams of the transmission UE, where the message transmitted to the transmission UE contains an identifier of the selected transmission beam. The identifier of the selected transmission beam includes a slot index, or a resource identifier of the one or more sidelink reference signals.

In some examples, the message transmitted to the transmission UE can contain the information related to the signal strength measurements, and the method further comprising receiving a message from the transmission UE that includes an indication of the selected receiving beam selected from the one or more receiving beams of the UE by the transmission UE.

In some examples, the method may further include transmitting a beam pairing request from the UE before receiving the one or more sidelink reference signals from the transmission UE. The transmitting the beam pairing request may be triggered by a timer or an event, and the beam pairing request may be contained in a medium access control (MAC) control element (CE) or sidelink control information (SCI) stage 2.

This Summary is provided merely for purposes of illustrating some aspects to provide an understanding of the subject matter described herein. Accordingly, the above-described features are merely examples and should not be construed to narrow the scope or spirit of the subject matter in this disclosure. Other features, aspects, and advantages of this disclosure will become apparent from the following Detailed Description, Figures, and Claims.

The present disclosure is described with reference to the accompanying drawings.

In the drawings, generally, like reference numbers indicate identical or functionally similar elements. Additionally, generally, the left-most digit(s) of a reference number identifies the drawing in which the reference number first appears.

DETAILED DESCRIPTION

In a wireless system, a user equipment (UE) can communicate via uplink and downlink with a base station (for example, an evolved Node B (eNB), a next generation node B (gNB), or other base station) in a wireless communication network or system. In addition, a UE can communicate with one or more UEs directly by device-to-device (D2D) or sidelink (SL) communication through sidelink channels. Various sidelink channels are defined in an interface for sidelink communication, e.g., Physical Sidelink Control Channel (PSCCH) and physical sidelink shared channel (PSSCH) in a PC5 interface. Compared to the conventional cellular communication, sidelink communication can have many advantages, e.g., more efficient and transparent to achieve higher spectral efficiency and low latency. Other terms have been used to describe SL related communication systems, e.g., proximity service (ProSe) communication, D2D communication. Even though those terms, e.g., SL communication, D2D communication, ProSe communication, can differ from each other in some aspects. In the current disclosure, SL, D2D, and ProSe are used interchangeably. SL communication can operate using both licensed cellular spectrum (known as in-band communication) and unlicensed spectrum (known as out-band communication).

According to some aspects, in a wireless system, a UE can include an antenna having a plurality of antenna panels, where an antenna panel can include an array of antenna elements that can be located in close physical location. In some examples, an antenna can be a smart antenna system, where all antenna elements are considered as pseudo-omni or quasi-sector-omni antenna elements including a phase shifter. A directional beam, such as a transmission (TX) beam or a receiving (RX) beam, can be formed by adjusting the phase shifter of the antenna element. According to some aspects, for sidelink communication between multiple UEs, a transmission UE can have multiple TX beams such as N TX beams, and a receiver UE can have multiple RX beams such as M TX beams.

According to some aspects, in a wireless system, a TX/RX beam pairing operation or procedure may be performed between a transmission UE and a receiver UE so that data communication between the transmission UE and the receiver UE can happen. During the beam pairing operation or procedure, a specific or selected transmission beam is selected from the multiple transmission beams of the transmission UE, and a selected receiving beam is selected from the multiple receiving beams of the receiver UE, so that data are transmitted between the transmission UE and the receiver UE using the selected transmission beam and the selected receiving beam.

However, various technical problems may occur during the beam pairing procedure between a transmission UE and a receiver UE for sidelink communication. Performing the beam pairing procedure by broadcasting operations among all the UEs in the communication range can be inefficient in terms of resource overhead or power consumption of the UE. In the unicast based beam pairing procedure, operations based on some limited types of sidelink reference signals and signal strength measurements of the one or more sidelink reference signals are performed. For example, some systems may only provide a channel state information reference signal configured by PC5-RRC configuration, and the measurement of the reference signals may be limited to a channel quality indicator. In addition, the procedures performed between the transmission UE and the receiver UE may be inefficient and not flexible.

Some aspects of this disclosure provide improved solutions to a TX/RX beam pairing procedure performed between a transmission UE and a receiver UE for sidelink communication. A UE can either perform the function of a transmission UE or a receiver UE. Accordingly, a UE can be either a transmission UE or a receiver UE. The beam pairing procedure presented herein can have the flexibility that either the transmission UE or the receiver UE can initialize the beam pairing procedure, and the selected transmission beam or the selected receiving beam can be determined by either the transmission UE or the receiver UE. In addition, the selection of the TX/RX beam pair can be performed among a set of beam patterns to be used in a beam pairing procedure, which may be a smaller subset of all the possible N*M beam pairs between the N TX beams of the transmission UE and the M RX beams of the receiver UE. The set of beam patterns can be configured on both the transmission UE and the receiver UE. Since the set of beam patterns is smaller than all the possible N*M beam pairs, the efficiency for the selection of the beam pair can be improved.

The UEs disclosed herein can operate in a wireless communication system based on 3rd Generation Partnership Project (3GPP) release 16 (Rel-16), release 17 (Rel-17), or a New Radio (NR) system. However, these 3GPP release versions are not meant to be limiting. Although some examples of the contents of SL communication among multiple UEs are provided above, the aspects of this disclosure are not limited to these examples and SL communication among multiple UEs can include less, more, or other parameters, instructions, and/or information.

FIG.1illustrates an example wireless network100implementing designs for sidelink communications among multiple UEs, according to some aspects of the disclosure. The wireless system100is provided for the purpose of illustration only and does not limit the disclosed aspects. The system100can include, but is not limited to, a network node (herein referred to as a base station)101and multiple UEs, e.g., a UE102, a UE103, a UE104, a UE106, a UE108.

According to some aspects, the base station101can include a node configured to operate based on a wide variety of wireless communication techniques such as, but not limited to, techniques based on 3GPP standards. For example, base station101can include a node configured to operate using Rel-16, Rel-17, or others. The base station101can be a fixed station, and may also be called a base transceiver system (BTS), an access point (AP), a transmission/reception point (TRP), an evolved NodeB (eNB), a next generation node B (gNB), or some other equivalent terminology. The system100can operate using both licensed cellular spectrum (known as in-band communication) and unlicensed spectrum (known as out-band communication).

According to some aspects, a UE, e.g., the UE102, the UE103, the UE104, the106, or the UE108, can be configured to operate based on a wide variety of wireless communication techniques. These techniques can include, but are not limited to, techniques based on 3rd Generation Partnership Project (3GPP) standards. For example, referring toFIG.1, the UE102can be configured to operate using Rel-16, Rel-17 or later. UE102, UE103, UE104, UE106, or UE108, can include, but is not limited to, a wireless communication device, a smart phone, a laptop, a desktop, a tablet, a personal assistant, a monitor, a television, a wearable device, an Internet of Things (IoTs), a vehicle's communication device, a mobile station, a subscriber station, a remote terminal, a wireless terminal, a user device, or the like.

According to some aspects, base station101communicates with the multiple UEs within a coverage area111, e.g., UE102, UE104, UE103, while UE106and UE108are outside the coverage area111. Among them, UE103is a relay UE. A UE within the coverage area111, e.g., UE102, communicates with the base station101in uplink (UL) and downlink (DL) through a communication interface, e.g., a Uu interface.

According to some aspects, a UE can perform SL communication with another UE. For example, UE102can perform SL communication with UE104, UE106, and UE108. UE104is an in-coverage UE with respect to UE102and base station101since both UE102and UE104are within coverage area111of base station101. UE106is a partial-coverage UE with respect to UE102and base station101since UE106is outside coverage area111but UE102is within coverage area111and operates a link112with UE102. Furthermore, UE106can perform SL communication with UE108, where both UE106and UE108are an out-of-coverage UE since both UE106and UE108are out of coverage area111of base station101.

According to some aspects, a UE can perform SL communication with another UE over a SL link through an interface, e.g., PC5 interface, which is different from the interface between the UE and the base station. The interface for SL communication between UEs can support one-to-many and/or any-to-any communication between a group of UEs. For example, UE102and UE106can communicate over link112through the PC5 interface. A message can be sent from UE102to UE106using SL communication by a broadcast transmission, a groupcast transmission, or a unicast transmission.

According to some aspects, a UE can perform SL communication with another UE for various applications. For example, UE102can perform SL communication with UE106for public safety use or commercial application, to provide a data offloading facility that can reduce the overall network overhead, for indoor installation and positioning, for machine type communication (MTC), or more. UE102can perform vehicle-to-vehicle (V2V) communication and vehicle-to-everything (V2X) communication with UE106by SL communication. For example, UE102and UE106can be two vehicles. UE102can be a vehicle running at high speed that warns UE106, which is a nearby vehicle, using link112before it changes highway lanes.

According to some aspects, UE102can include an antenna having a plurality of antenna panels, e.g., an antenna panel117, and an antenna panel118. In general, an antenna can include one or more antenna panels. An antenna panel can include an array of antenna elements that can be located in close physical location. Any antenna element, can be an omnidirectional antenna element, a quasi-omnidirectional antenna element, a directional antenna element, or any other antenna element. In some examples, antenna can be a smart antenna system, where all antenna elements are considered as pseudo-omni or quasi-sector-omni antenna elements including a phase shifter. A directional beam, such as such as a TX beam or a RX beam, can be formed by adjusting the phase shifter of the antenna element. Accordingly, antenna panel117can provide corresponding antenna beam (herein “beam”)122, beam124, beam126. And antenna panel119can provide beam151, beam153, or beam155, which can either be a transmission beam or a receiving beam. Antenna panel117, antenna panel118, and antenna panel119are only shown as examples. In some examples, there can be more or fewer antenna panels, and an antenna panel can include 2, 4, 8, 16, or other number of antenna elements, which can include a dipole antenna element, a monopole antenna element, a patch antenna element, a loop antenna element, a microstrip antenna element, or any other type of antenna elements suitable for transmission of RF signals.

According to some aspects, UE102can include a transceiver131and a processor133communicatively coupled to transceiver131. Transceiver131can be configured to wirelessly communicate through an interface for sidelink communication with one or more UEs including a receiver UE, such as UE108. According to some aspects, processor133can configure a set of beam patterns142to be used in a beam pairing procedure between a transmission UE and a receiver UE. When UE102functions as a transmission UE, processor133can transmit one or more sidelink reference signals141to the receiver UE, and receive a message143from the receiver UE. When UE102functions as a receiver UE, processor133can perform signal strength measurements144of the one or more sidelink reference signals. Other UEs, such as UE104, UE106, UE108can have a structure similar to UE102. UE108can include a transceiver135and a processor137, which may perform similar functions as transceiver131and processor133.

According to some aspects, UE102, or any other UE can be implemented according to a block diagram as illustrated inFIG.2.

Referring toFIG.2, UE102can have antenna panel117including one or more antenna elements to form various beams, e.g., beam122, beam124, or beam126, coupled to transceiver131and controlled by processor133. Transceiver131and antenna panel117can be configured to enable wireless communication in a wireless network, such as wireless network100, including wireless communication with UE108and base station101. In detail, transceiver113can include radio frequency (RF) circuitry216, transmission circuitry212, and reception circuitry214to enable wireless communication with other UEs and/or a base station as discussed for wireless network100. RF circuitry216can include multiple parallel RF chains for one or more of transmit or receive functions, each connected to one or more antenna elements of the antenna panel. In addition, processor133can be communicatively coupled to a memory201, which are further coupled to the transceiver131. Various data can be stored in memory201.

In some examples, memory201can store one or more sidelink reference signals141, message143, or signal strength measurements144. Memory201can store the set of beam patterns142to be used in a beam pairing procedure. The set of beam patterns142can include one or more transmission beams of the UE, and one or more receiving beams of the receiver UE. As shown inFIG.1, UE102can generate beam122, beam124, beam126, and UE108can generate beam151, beam153, and beam155. In theory, there could be 3*3 different beam pairs for data communication between UE102and UE108. However, the number of beams is not limited to this 3*3 construct. A transmission beam can be selected from beam122, beam124, and beam126, while a receiving beam can be selected from beam151, beam153, and beam155. The total 3*3=9 possible pairs of a transmission beam and a receiving beam can be represented as A={(122,151), (124,151), (126,151), (122,153), (124,153), (126,153), (122,155), (124,155), (126,155)}. To reduce the candidates for the selection of a pair of a transmission beam and a receiving beam, the set of beam patterns142can be a subset of the set of all possible pairs of a transmission beam and a receiving beam. For example, the set of beam patterns142can be subset B={(122,151), (124,151), (122,155), (124,155), (126,155)}, which is a subset of all possible beam patterns A. Since the set of beam patterns142may be smaller than all the possible N*M beam pairs, the efficiency for the selection of the beam pair can be improved.

Based on the discussion herein, it will apparent that the other UEs103,104,106, and108inFIG.1can have a same or similar structure to that described for UE102inFIG.2.

In some embodiments, memory201can store instructions, that when executed by processor133perform or cause to perform operations described herein, e.g., operations to perform a beam pairing procedure for sidelink communications. Alternatively, processor133can be “hard-coded” to perform the operations described herein. In some embodiments, processor133can be configured to perform operations described forFIG.3Awhen UE102functions as a transmission UE orFIG.3Bwhen UE102functions as a receiver UE, as will be understood by one skilled in the art.

FIGS.3A-3Billustrate example process310and process320performed by a transmission UE and a receiver UE to perform a beam pairing procedure for sidelink communications, according to some aspects of the disclosure. Process310and process320can be performed by UE102, UE104, UE106, or UE108, which may be implemented as shown inFIG.2. Process310and process320may also be performed by a computer system700ofFIG.7. Process310and process320are not limited to the specific aspects depicted in those figures and other systems may be used to perform the method as will be understood by those skilled in the art. It is to be appreciated that not all operations may be needed, and the operations may not be performed in the same order as shown in process310and process320.

UE102functions as a transmission UE, where data communication is transmitted from the transmission UE to a receiver UE such as UE108.

At312, processor133of UE102can configure the set of beam patterns142to be used in a beam pairing procedure. For example, the set of beam patterns142can be C={(122,151), (124,151), (122,155), (124,155)}. The set C includes one or more transmission beams of UE102(beam122and beam124), and one or more receiving beams (beam151and beam155) of UE108.

At314, processor133of UE102can transmit, using one or more beam patterns of the set of beam patterns, the one or more sidelink reference signals141to the receiver UE. In some examples, the one or more sidelink reference signals141can include a sidelink channel state information reference signal (CSR-RS). In some examples, the one or more sidelink reference signals141can be carried using a physical sidelink shared channel (PSSCH) that carries data information. In some examples, UE102can further be configured to receive a beam pairing request from the receiver UE before transmitting the one or more sidelink reference signals141to the receiver UE.

At316, processor133of UE102can receive message143from the receiver UE, which can be UE108. Message143may contain information related to signal strength measurements144on the one or more beam patterns based on the one or more sidelink reference signals141. The signal strength measurements144performed on the one or more beam patterns based on the one or more sidelink reference signals141can include a Reference Signal Receive Power (RSRP) measurement, a Reference Signal Received Quality (RSRQ), or a Signal to Interference & Noise Ratio (SINR).

At318, based on the received message143, processor133of UE102can further determine a selected transmission beam selected from the one or more transmission beams of UE102for signal transmissions from UE102to the receiver UE. For example, processor133can determine the selected transmission beam to be beam122based on one or more transmission beams of UE102defined by the set of beam patterns C={(122,151), (124,151), (122,155), (124,155)}. In some examples, the receiver UE108can make a selection for the selected transmission beam, and message143received from the receiver UE108can contain an identifier of the selected transmission beam selected by the receiver UE108. In such a situation, processor133can determine the selected transmission beam by reading the identifier of the selected transmission beam contained in message143.

At step319, processor133can transmit data from UE102to UE108using the selected transmission beam122.

It will be understood that the transmit and receive operations discussed herein for process310can be enabled at least in part by transceiver131and/or antenna panel117.

In some embodiments, to determine the selected transmission beam, processor133can select the selected transmission beam of UE102and a related receiving beam of the receiver UE based on the information related to the signal strength measurements on the one or more beam patterns based on the one or more sidelink reference signals. Afterwards, processor133can transmit an indication to the receiver UE108to indicate the selected transmission beam and the related receiving beam of the receiver UE108. The indication to indicate the selected transmission beam and the related receiving beam includes a quasi-co-location (QCL) indication.

Process320shown inFIG.3Bdescribes operations performed by a receiver UE such as UE108, where data communication is transmitted from a transmission UE such as UE102to UE108.

At322, processor137of UE108can configure the set of beam patterns142to be used in a beam pairing procedure, where the set of beam patterns142is the same set of beam patterns used to configure the transmission UE such as UE102.

At324, processor137of UE108can receive one or more sidelink reference signals141from transmission UE102. The one or more sidelink reference signals141may be carried by a PSSCH that carries data information. In some examples, the one or more sidelink reference signals includes a sidelink (SL) channel state information reference signal (CSR-RS). In some examples, processor137of UE108can transmit a beam pairing request to the transmission UE102before receiving the one or more sidelink reference signals141from the transmission UE102. The transmitting the beam pairing request to the transmission UE102can be triggered by a timer or an event, and the beam pairing request can be contained in a MAC CE or in SCI stage 2.

At326, processor137of UE108can perform signal strength measurements144on the one or more beam patterns based on the one or more sidelink reference signals141. The signal strength measurements144of the one or more sidelink reference signals141can include a RSRP measurement, a RSRQ measurement, or a SINR measurement.

At328, processor137of UE108can transmit message143to the transmission UE102. Message143may contain information related to the signal strength measurements144of the one or more sidelink reference signals141. In some examples, message143may be transmitted by a physical sidelink feedback channel (PSFCH).

In some examples, processor137of UE108can further determine a selected transmission beam selected from the one or more transmission beams of the transmission UE102. In such examples, message143transmitted to the transmission UE102can contain an identifier of the selected transmission beam. The identifier of the selected transmission beam can include a slot index, or a resource identifier of the one or more sidelink reference signals.

At329, processor137of UE108can determine a selected receiving beam selected from the one or more receiving beams of the UE for receiving signal transmissions from the transmission UE. In some examples, UE108can make the selection to determine the selected receiving beam. In some other examples, the transmission UE102can make the selection to determine the selected receiving beam. Accordingly, UE108can receive a message from the transmission UE102that includes an indication of the selected receiving beam selected from the one or more receiving beams of the UE by the transmission UE102.

At330, processor137of UE108can receive data from the transmission UE102using the selected receiving beam.

It will be understood that the transmit and receive operations discussed herein for process320can be enabled at least in part by transceiver135and/or antenna panel119.

FIGS.4A-4Billustrate example process410and process420performed by a transmission UE and a receiver UE for a beam pairing procedure for sidelink communications, according to some aspects of the disclosure.

As shown inFIG.4A, process410can be an implementation and example of process310, which can be performed by a transmission UE such as UE102.

At412, processor133of UE102can configure the set of beam patterns142to be used in a beam pairing procedure with a receiver UE. Operations performed at412can be examples of operations performed at312. The configuration of the set of beam patterns142may include configuring various parameters such as a total number of beam transmissions for beam pairing, initial transmission and retransmission, a time window of the beam pairing procedure, and the set of beam pairs to be used in the beam pairing procedure. For example, transport block 1 (TB1) transmission can initially be transmitted with beam122, and TB1 retransmission can be transmitted with beam124; transport block 2 (TB2) transmission can initially be transmitted with beam124, and TB2 retransmission can be transmitted with the same beam124; TB1 initial transmission and retransmission are both transmitted with beam122; TB2 initial transmission and retransmission are both transmitted with beam124; TB1 initial transmission can be transmitted by both beam122and beam124, and TB1 retransmission can be transmitted with beam124and beam126.

At414, processor133of UE102can transmit one or more sidelink reference signals by PSSCH with different transmission beams to the receiver UE. Operations performed at414can be examples of operations performed at314. The PSSCH can include SL CSI-RS for RSRP measurement, SCI to indicate the start of the beam pairing procedure. In addition, dummy PSSCH may be used for the beam pairing. The transmission of PSSCH with different beams may be triggered by various mechanisms. For example, PSSCH transmission can be triggered periodically, based on a request from a base station, or based on a detection of an existence of a receiver UE.

At416, processor133of UE102can receive from the receiver UE the indicated paired transmission beam identifier (ID) for the transmission beam. Operations performed at416can be examples of operations performed at316and318, where the message received contains the ID of the transmission beam. The selection of the transmission beam of UE102can be performed by the receiver UE108. If no transmission beam ID is received from the receiver UE within a certain time, UE102can retransmit the one or more sidelink reference signals by PSSCH to the receiver UE. Retransmission of the PSSCH could have same set of beams or different sets of beams from the initial PSSCH transmissions. Certain time gap may be introduced between the PSSCH transmission and PSSCH retransmission for beam pairing.

At419, processor133of UE102can transmit a PSSCH data transmission to the receiver UE using the indicated transmission beam ID for the PSSCH data transmission. Optionally, UE102may send an acknowledgement (ACK) to the receiver UE108to confirm the reception of the transmission beam ID indication from the receiver UE108.

It will be understood that the transmit and receive operations discussed herein for process410can be enabled at least in part by transceiver131and/or antenna panel117.

As shown inFIG.4B, process420can be an implementation or an example of process320, which can be performed by a receiver UE such as UE108.

At422, processor137of UE108can configure the set of beam patterns142to be used in a beam pairing procedure with a transmission UE such as UE102. Operations performed at422can be examples of operations performed at322, with details described similarly as operations performed at412by the transmission UE.

At424, processor137of UE108can receive one or more sidelink reference signals carried by PSSCH with different receiving beams from the transmission UE such as UE102. Operations performed at424can be examples of operations performed at324, with details described similarly as operations performed at414by the transmission UE.

At426, to measure the strength of different transmission beams, processor137of UE108can perform signal strength measurements144of the one or more sidelink reference signals141. Operations performed at426can be examples of operations performed at326and at328. If more than one retransmission uses the same transmission beam, then the averaged RSRP measurement or the later in time RSRP measurement is used for the transmission beam. In some embodiments, PSSCH RSRP or PSCCH RSRP can be measured. In addition, UE108can make the selection of the selected transmission beam based on the signal strength measurements144on various transmission beams. The selection can be based on configuration, such as resource pool (pre)configuration or PC5-RRC configuration between a pair of UEs.

In some embodiments, processor137of UE108can further transmit message143to the transmission UE102to report the selected transmission beam for the UE102. The message143can include various contents. In some embodiments, message143can include only the transmission beam ID corresponding to the strongest RSRP (or SINR) measured by UE108, without a separate RSRP measurement reporting, such as per beam or per PSSCH transmission. The transmission beam ID may be represented by the order of the PSSCH transmission, or represented by the slot index of the corresponding PSSCH transmission (with the strongest RSRP value). Additionally and alternatively, the transmission beam ID may be represented by the CSI-RS resource ID. In some embodiments, message143can include multiple transmission beam ID whose signal strength measurements may be stronger than a threshold and which corresponds to the same receiver beam.

In some embodiments, message143can be transmitted by a PSFCH transmission corresponding to the last PSCCH/PSSCH transmission for the beam pairing procedure. The PSFCH transmission priority can be (pre)configured per resource pool or based on SL beam pairing configuration. The PSFCH transmission for beam pairing may have a higher priority than PSFCH for SL HARQ or inter-UE coordination. The PSFCH transmission for beam pairing may have a lower priority than PSFCH for SL HARQ or inter-UE coordination. In some embodiments, message143can be transmitted by a PSCCH/PSSCH transmission. The PSCCH/PSSCH transmission may follow a legacy resource selection procedure, and packet delay budget (PDB) may be (pre)configured per resource pool or based on SL beam pairing configuration. Similarly, data priority may be (pre)configured per resource pool or based on SL beam pairing configuration.

At429, processor137of UE108can receive data using the receiving beam corresponding to the reported transmission beam contained in message143. In some embodiments, the receiver UE108does not need to be informed by the transmission UE102for the paired beam, UE108can autonomously receive data using the receiving beam corresponding to the reported transmission beam. UE108may receive data using the receiving beam at a time instance of some offset after sending the message143to UE102. The offset may be pre-defined or (pre)configured per resource pool or configured during PC5-RRC configuration. In some other embodiments, UE108may receive data using the receiving beam corresponding to the reported transmission beam contained in message143after receiving an acknowledgement (ACK) message for message143to indicate that message143has been received. The ACK message can be a SCI stage 2 message to indicate the reception of beam reporting message143by UE102. Additionally and alternatively, the ACK message can be a MAC CE message to indicate the reception of beam reporting message143by UE102. Furthermore, in some embodiments, the ACK message can be sent based on a timer ACK for CG-PUSCH. In some embodiments, a time gap may be applied between beam reporting message143being sent and the use of the corresponding receiving beam by UE108. If the message143is sent by a PSSCH transmission, the ACK message to the PSSCH transmission of message143can be the slot to receive data using the receiving beam corresponding to the reported transmission beam contained in message143.

It will be understood that the transmit and receive operations discussed herein for process420can be enabled at least in part by transceiver135and/or antenna panel119.

FIGS.5A-5Billustrate example process510and process520performed by a transmission UE and a receiver UE for a beam pairing procedure for sidelink communications, according to some aspects of the disclosure.

As shown inFIG.5A, process510can be an implementation of process310. Previously, process410inFIG.4Ashows the one or more sidelink reference signals by PSSCH are sent by the transmission UE102without being triggered by a receiving UE. Alternatively, process510shows the one or more sidelink reference signals carried by PSSCH are triggered by a request from the receiver UE108.

At512, processor133of UE102can configure the set of beam patterns142to be used in a beam pairing procedure. Operations performed at512can be examples of operations performed at312. Details of operations performed at512can be similar to details of operations performed at412.

At513, processor133of UE102can receive a beam pairing request from a receiver UE. The request can trigger the transmission UE to send multiple sidelink reference signals repeatedly transmitted with different transmission beams. The beam pairing request can be sent via a SCI stage 2 message, or a MAC CE. The beam pairing request may be triggered based on some events or timer. For example, the beam pairing request may be triggered when several continuous PSSCH decoding failures are detected, when the receiver UE wants to set up the sidelink connection with the transmission UE, when the receiver UE has some sidelink data to be sent to the transmission UE where data priority is higher than a threshold, or some other events.

At514, processor133of UE102can transmit, one or more sidelink reference signals by PSSCH with different transmission beams. Operations performed at514can be examples of operations performed at314with details similar to the details described for operations performed at414.

At516, processor133of UE102can receive from the receiver UE the indicated paired beam ID for the transmission beam. Operations performed at416can be examples of operations performed at316and318, where the message received contains the ID of the transmission beam. Operations performed at516can have details similar to the details described for operations performed at416by the transmission UE102.

At519, processor133of UE102can transmit a PSSCH data transmission to the receiver UE using the indicated transmission beam ID for the PSSCH data transmission. Operations performed at519can have details similar to the details described for operations performed at419by the transmission UE102.

It will be understood that the transmit and receive operations discussed herein for process510can be enabled at least in part by transceiver131and/or antenna panel117.

As shown inFIG.5B, process520can be an implementation of process320, which can be performed by a receiver UE such as UE108. Process520shows the one or more sidelink reference signals carried by PSSCH are triggered by a request from the receiver UE108.

At522, processor137of UE108can configure the set of beam patterns142to be used in a beam pairing procedure. Operations performed at522can be examples of operations performed at322. Details of operations performed at522can be similar to details of operations performed at422.

At523, processor137of UE108can send the beam pairing request to the transmission UE to trigger the transmission UE sending multiple signals repeatedly with different transmission beams. The beam pairing request may be triggered based on some events or timer. For example, the beam pairing request may be triggered when several continuous PSSCH decoding failures are detected, when the receiver UE wants to set up the sidelink connection with the transmission UE, when the receiver UE has some sidelink data to be sent to the transmission UE where data priority is higher than a threshold, or some other events. The beam pairing request can be sent via a SCI stage 2 message, or a MAC CE. The content of the beam pairing request can include the beam patterns to be used to transmit one or more sidelink reference signals, beam pairing starting time, and other parameters. The beam pairing request can have a priority (pre)configured per resource pool.

At524, processor137of UE108can receive the one or more sidelink reference signals carried by PSSCH with different transmission beams from the transmission UE. Operations performed at524can be examples of operations performed at324with details similar to the details described for operations performed at424.

At526, processor137of UE108can perform signal strength measurements144of the one or more sidelink reference signals141, and can further transmit message143to the transmission UE102to report the selected transmission beam for the UE102. Operations performed at526can be examples of operations performed at326and328, with details similar to the details described for operations performed at426.

At529, processor137of UE108can receive data communication from transmission UE102using the receiving beam corresponding to the reported transmission beam contained in message143. Operations performed at529can have details similar to the details described for operations performed at429.

It will be understood that the transmit and receive operations discussed herein for process520can be enabled at least in part by transceiver135and/or antenna panel119.

FIGS.6A-6Billustrate example process610and process620performed by a transmission UE and a receiver UE for a beam pairing procedure for sidelink communications, according to some aspects of the disclosure.

As shown inFIG.6A, process610can be an implementation of process310. Previously, in process410and process510, the receiver UE108makes the selection of the transmission beam and sends message143to transmission UE102to indicate the selected transmission beam. Alternatively, process610shows the operations performed by transmission UE102to make the selection of the transmission beam and potentially the corresponding receiving beam for receiver UE108.

At612, processor133of UE102can configure the set of beam patterns142to be used in a beam pairing procedure with a receiver UE. Operations performed at612can be examples of operations performed at312.

At614, processor133of UE102transmits one or more sidelink reference signals by PSSCH with different transmission beams to the receiver UE. Operations performed at614can be examples of operations performed at314.

At616, processor133of UE102can receive from the receiver UE108message143containing information related to signal strength measurements on the one or more beam patterns based on the one or more sidelink reference signals. In some example, the receiver UE108performs signal strength measurements such as L1-RSRP or L1-SINR measurements. Operations performed at616can be examples of operations performed at316.

At618A, processor133of UE102can perform the transmission beam selection to include a Quasi-co-location (QCL) indication. In some embodiments, processor133of UE102can determine the transmitting beam corresponding to the highest beam strength in the reported beam strengths. In some embodiments, processor133of UE102can also determine the receiving beam of the receiver UE108based on the transmission beam selection. Operations performed at618A can be examples of operations performed at318.

At618B, processor133of UE102can transmit an indication to the receiver UE108to indicate the selected transmission beam and the related receiving beam of the receiver UE108. Operations performed at618B can be examples of operations performed at318. In some embodiments, the indication to indicate the selected transmission beam and the related receiving beam of the receiver UE108may be the QCL indication providing a CSI-RS as the source reference signal for QCL-TypeD (spatial Rx parameter) indication. In some embodiments, the QCL indication may be common for multiple channels or dedicated for each channel, e.g. PSSCH, PSCCH, PSFCH and so on. In some embodiments, for PSFCH, the beam indication is to provide a spatial relation indication to determine the transmission beam. The QCL indication may be provided based on transmission configuration indicator (TCI), where the TCI index can be indicated by SCI or MAC CE.

At619, processor133of UE102can transmit, a PSSCH data transmission to the receiver UE using the indicated transmission beam ID for the PSSCH data transmission. Operations performed at619can have details similar to the details described for operations performed at419by the transmission UE102.

It will be understood that the transmit and receive operations discussed herein for process610can be enabled at least in part by transceiver131and/or antenna panel117.

As shown inFIG.6B, process620can be an implementation of process320. Previously, in process420and process520, the receiver UE108makes the selection of the transmission beam and sends message143to transmission UE102to indicate the selected transmission beam. Alternatively, process620shows the operations performed by transmission UE102to make the selection of the transmission beam and potentially the corresponding receiving beam for receiver UE108.

At622, processor137of UE108can configure the set of beam patterns142to be used in a beam pairing procedure with a receiver UE. Operations performed at622can be examples of operations performed at322.

At624, processor137of UE108can receive the one or more sidelink reference signals carried by PSSCH with different transmission beams from the transmission UE. Operations performed at624can be examples of operations performed at324with details similar to the details described for operations performed at424.

At626, processor137of UE108can perform signal strength measurements144of the one or more sidelink reference signals141, and can further transmit message143to the transmission UE102to report the selected transmission beam for the UE102. Operations performed at626can be examples of operations performed at326and328, with details similar to the details described for operations performed at426.

At627, processor137of UE108can receive an indication from the transmission UE102to indicate the receiving beam of the receiver UE108corresponding to a transmission beam selected by UE102. In some embodiments, the indication to indicate the selected transmission beam and the related receiving beam of the receiver UE108may be the QCL indication providing a CSI-RS as the source reference signal for QCL-TypeD (spatial Rx parameter) indication.

At629, processor137of UE108can receive data communication from transmission UE102using the receiving beam corresponding to the reported transmission beam contained in message143. Operations performed at529can have details similar to the details described for operations performed at429.

It will be understood that the transmit and receive operations discussed herein for process620can be enabled at least in part by transceiver135and/or antenna panel119.

Various aspects can be implemented, for example, using one or more computer systems, such as computer system700shown inFIG.7. Computer system700can be any computer capable of performing the functions described herein such as UE102, UE103, UE104, UE106, UE108in inFIG.1. Computer system700includes one or more processors (also called central processing units, or CPUs), such as a processor704. Processor704is connected to a communication infrastructure706(e.g., a bus). Computer system700also includes user input/output device(s)703, such as monitors, keyboards, pointing devices, etc., that communicate with communication infrastructure706through user input/output interface(s)702. Computer system700also includes a main or primary memory708, such as random access memory (RAM). Main memory708may include one or more levels of cache. Main memory708has stored therein control logic (e.g., computer software) and/or data.

Computer system700may also include one or more secondary storage devices or memory710. Secondary memory710may include, for example, a hard disk drive712and/or a removable storage device or drive714. Removable storage drive714may be a floppy disk drive, a magnetic tape drive, a compact disk drive, an optical storage device, tape backup device, and/or any other storage device/drive.

Removable storage drive714may interact with a removable storage unit718. Removable storage unit718includes a computer usable or readable storage device having stored thereon computer software (control logic) and/or data. Removable storage unit718may be a floppy disk, magnetic tape, compact disk, DVD, optical storage disk, and/ any other computer data storage device. Removable storage drive714reads from and/or writes to removable storage unit718in a well-known manner.

According to some aspects, secondary memory710may include other means, instrumentalities or other approaches for allowing computer programs and/or other instructions and/or data to be accessed by computer system700. Such means, instrumentalities or other approaches may include, for example, a removable storage unit722and an interface720. Examples of the removable storage unit722and the interface720may include a program cartridge and cartridge interface (such as that found in video game devices), a removable memory chip (such as an EPROM or PROM) and associated socket, a memory stick and USB port, a memory card and associated memory card slot, and/or any other removable storage unit and associated interface.

In some examples, main memory708, the removable storage unit718, the removable storage unit722can store instructions that, when executed by processor704, cause processor704to perform operations for a UE, e.g., UE102, UE103, UE104, UE106, UE108inFIG.1. In some examples, the operations can include operations described inFIGS.3A-3B,FIGS.4A-4B,FIGS.5A-5B, orFIGS.6A-6B,

Computer system700may further include a communication or network interface724. Communication interface724enables computer system700to communicate and interact with any combination of remote devices, remote networks, remote entities, etc. (individually and collectively referenced by reference number728). For example, communication interface724may allow computer system700to communicate with remote devices728over communications path726, which may be wired and/or wireless, and which may include any combination of LANs, WANs, the Internet, etc. Control logic and/or data may be transmitted to and from computer system700via communication path726.

The operations in the preceding aspects can be implemented in a wide variety of configurations and architectures. Therefore, some or all of the operations in the preceding aspects may be performed in hardware, in software or both. In some aspects, a tangible, non-transitory apparatus or article of manufacture includes a tangible, non-transitory computer useable or readable medium having control logic (software) stored thereon is also referred to herein as a computer program product or program storage device. This includes, but is not limited to, computer system700, main memory708, secondary memory710and removable storage units718and722, as well as tangible articles of manufacture embodying any combination of the foregoing. Such control logic, when executed by one or more data processing devices (such as computer system700), causes such data processing devices to operate as described herein.

While the disclosure has been described herein with reference to exemplary aspects for exemplary fields and applications, it should be understood that the disclosure is not limited thereto. Other aspects and modifications thereto are possible, and are within the scope and spirit of the disclosure. For example, and without limiting the generality of this paragraph, aspects are not limited to the software, hardware, firmware, and/or entities illustrated in the figures and/or described herein. Further, aspects (whether or not explicitly described herein) have significant utility to fields and applications beyond the examples described herein.

Aspects have been described herein with the aid of functional building blocks illustrating the implementation of specified functions and relationships thereof. The boundaries of these functional building blocks have been arbitrarily defined herein for the convenience of the description. Alternate boundaries can be defined as long as the specified functions and relationships (or equivalents thereof) are appropriately performed. In addition, alternative aspects may perform functional blocks, steps, operations, methods, etc. using orderings different from those described herein.

The breadth and scope of the disclosure should not be limited by any of the above-described exemplary aspects, but should be defined only in accordance with the following claims and their equivalents.

For one or more embodiments or examples, at least one of the components set forth in one or more of the preceding figures may be configured to perform one or more operations, techniques, processes, and/or methods as set forth in the example section below. For example, circuitry associated with a UE, base station, network element, etc. as described above in connection with one or more of the preceding figures may be configured to operate in accordance with one or more of the examples set forth below in the example section.