Patent Description:
Wireless communication systems are widely deployed to provide various telecommunication services such as telephony, video, data, messaging, broadcasts, etc. These wireless communication systems may employ multiple-access technologies capable of supporting communication with multiple users by sharing available system resources (e.g., bandwidth, transmit power, or other resources). Multiple-access technologies can rely on any of code division, time division, frequency division, orthogonal frequency division, single-carrier frequency division, or time division synchronous code division multiple access (TD-SCDMA) systems, to name a few. These and other multiple access technologies have been adopted in various telecommunication standards to provide a common protocol that enables different wireless devices to communicate on a municipal, national, regional, and even global level.

Sidelink communications are communications from one UE to another UE. As the demand for mobile broadband access continues to increase, there exists a need for further improvements in NR and LTE technology, including improvements to sidelink communications. These improvements should be applicable to other multi-access technologies and the telecommunication standards that employ these technologies.

Document <CIT> relates to a method and apparatus from the perspective of a first device to perform sidelink communication. The method includes the first device performing sidelink resource selection or reselection procedure for a sidelink transmission to a second device, wherein the sidelink resource selection or reselection procedure is performed to select at least one sidelink resource from candidate sidelink resources within a time duration of selection window. The method further includes the first device selecting a first sidelink resource based on sidelink active time or wake-up time of the second device, wherein the first sidelink resource is within the time duration of selection window. The method also includes the first device performing the sidelink transmission on the first sidelink resource to the second device.

<NPL> relates to a discussion on sidelink DRX timer handling. The authors of the draft propose that RetransmissionTimerTX should be introduced on sidelink to provide opportunity for feedback transmission. RetransmissionTimerTX should be started at the start of feedback occasion.

The claimed invention is defined by the independent claims. Further embodiments of the claimed invention are described in the dependent claims.

The present disclosure is directed to a method for wireless communication performed by a transmitter according to claim <NUM>.

The present disclosure is further directed to an apparatus for wireless communication by a transmitter UE according to claim <NUM>.

The present disclosure is further directed to a method for wireless communication performed by a receiver according to claim <NUM>.

The present disclosure is further directed to an apparatus for wireless communication by a receiver UE according to claim <NUM>.

The present disclosure is further directed to a computer program according to claim <NUM>.

While aspects and embodiments are described in this application by illustration to some examples, those skilled in the art will understand that additional implementations and use cases may come about in many different arrangements and scenarios. Innovations described herein may be implemented across many differing platform types, devices, systems, shapes, sizes, packaging arrangements. For example, embodiments and/or uses may come about via integrated chip embodiments and other non-module-component based devices (e.g., end-user devices, vehicles, communication devices, computing devices, industrial equipment, retail/purchasing devices, medical devices, AI-enabled devices, etc.). While some examples may or may not be specifically directed to use cases or applications, a wide assortment of applicability of described innovations may occur. Implementations may range in spectrum from chip-level or modular components to non-modular, non-chip-level implementations and further to aggregate, distributed, or OEM devices or systems incorporating one or more aspects of the described innovations. In some practical settings, devices incorporating described aspects and features may also necessarily include additional components and features for implementation and practice of claimed and described embodiments. For example, transmission and reception of wireless signals necessarily includes a number of components for analog and digital purposes (e.g., hardware components including antenna, RF-chains, power amplifiers, modulators, buffer, processor(s), interleaver, adders/summers, etc.). It is intended that innovations described herein may be practiced in a wide variety of devices, chip-level components, systems, distributed arrangements, end-user devices, etc. of varying sizes, shapes, and constitution.

The following description and the appended figures set forth certain features for purposes of illustration.

The appended figures depict certain features of the various aspects described herein and are not to be considered limiting of the scope of this disclosure.

Aspects of the present disclosure provide apparatus, methods, processing systems, and computer readable mediums for handling retransmissions in sidelink communication. For example, a user equipment (UE) may implement of hybrid automatic repeat request (HARQ) timer and a retransmission timer during sidelink discontinuous reception (DRX) operations to manage retransmission of failed transmissions.

<FIG> illustrates an example of a wireless communication network <NUM> (e.g., an NR/<NUM> network) in which aspects described herein may be implemented.

For example, a user equipment (UE) 120a, a UE 120b, and/or a base station (BS) 110a of <FIG> may be configured to perform operations described below with reference to <FIG> and/or <FIG> to handle acknowledgement and retransmission timers during sidelink discontinuous reception (DRX) communication.

As illustrated in <FIG>, the wireless communication network <NUM> may include a number of BSs 110a-z (each also individually referred to herein as BS <NUM> or collectively as BSs <NUM>) and other network entities. In aspects of the present disclosure, a roadside service unit (RSU) may be considered a type of BS, and a BS <NUM> may be referred to as an RSU. The BSs <NUM> communicate with UEs 120a-y (each also individually referred to herein as UE <NUM> or collectively as UEs <NUM>) in the wireless communication network <NUM>.

According to certain aspects, the UEs <NUM> may be configured to recover a sidelink communication from another UE. As shown in <FIG>, UE 120a includes a sidelink manager <NUM> and UE 120b includes a sidelink manager <NUM>. The sidelink managers <NUM> and <NUM> may be configured to transmit a sidelink communication to each other or another UE, in accordance with aspects of the present disclosure.

Certain wireless networks (e.g., LTE) utilize orthogonal frequency division multiplexing (OFDM) on the downlink (DL) and single-carrier frequency division multiplexing (SC-FDM) on the uplink (UL).

NR may utilize OFDM with a CP on the UL and DL and include support for half-duplex operation using TDD.

BSs are not the only entities that may function as a scheduling entity.

ANC <NUM> may include one or more TRPs <NUM> (e.g., cells, BSs, gNBs, etc.).

The Radio Resource Control (RRC) layer, Packet Data Convergence Protocol (PDCP) layer, Radio Link Control (RLC) layer, Medium Access Control (MAC) layer, and a Physical (PHY) layers may be adaptably placed at the DU (e.g., TRP <NUM>) or CU (e.g., ANC <NUM>).

<FIG> illustrates an example physical architecture of a distributed RAN <NUM>, in accordance with certain aspects of the present disclosure.

<FIG> illustrates example components of BS 110a and UE 120a (as depicted in <FIG>), which may be used to implement aspects of the present disclosure. For example, antennas <NUM>, processors <NUM>, <NUM>, <NUM>, and/or controller/processor <NUM> of the UE 120a and/or antennas <NUM>, processors <NUM>, <NUM>, <NUM>, and/or controller/processor <NUM> of the BS 110a may be used to perform the various techniques and methods described herein with reference to <FIG>.

At the BS 110a, a transmit processor <NUM> may receive data from a data source <NUM> and control information from a controller/processor <NUM>. Each modulator may further process (e.g., convert to analog, amplify, filter, and upconvert) the output sample stream to obtain a DL signal. DL signals from modulators 432a through 432t may be transmitted via the antennas 434a through 434t, respectively.

At the UE 120a, the antennas 452a through 452r may receive the downlink signals from the BS 110a and may provide received signals to the demodulators (DEMODs) in transceivers 454a through 454r, respectively. Each demodulator may condition (e.g., filter, amplify, downconvert, and digitize) a respective received signal to obtain input samples. A MIMO detector <NUM> may obtain received symbols from all the demodulators in transceivers 454a through 454r, perform MIMO detection on the received symbols if applicable, and provide detected symbols. A receive processor <NUM> may process (e.g., demodulate, deinterleave, and decode) the detected symbols, provide decoded data for the UE 120a to a data sink <NUM>, and provide decoded control information to a controller/processor <NUM>.

On the UL, at UE 120a, a transmit processor <NUM> may receive and process data (e.g., for the physical uplink shared channel (PUSCH)) from a data source <NUM> and control information (e.g., for the physical uplink control channel (PUCCH) from the controller/processor <NUM>. The symbols from the transmit processor <NUM> may be precoded by a TX MIMO processor <NUM> if applicable, further processed by the demodulators in transceivers 454a through 454r (e.g., for SC-FDM, etc.), and transmitted to the BS 110a. At the BS 110a, the UL signals from the UE 120a may be received by the antennas <NUM>, processed by the modulators <NUM>, detected by a MIMO detector <NUM> if applicable, and further processed by a receive processor <NUM> to obtain decoded data and control information sent by the UE 120a.

The controllers/processors <NUM> and <NUM> may direct the operation at the BS 110a and the UE 120a, respectively. The processor <NUM> and/or other processors and modules at the BS 110a may perform or direct the execution of processes for the techniques described herein. As shown in <FIG>, the controller/processor <NUM> of the UE 120a has a sidelink manager <NUM> that may be configured for transmitting a sidelink communication to another UE. Although shown at the controller/processor <NUM> and controller/processor <NUM>, other components of the UE 120a and BS 110a may be used performing the operations described herein. A scheduler <NUM> may schedule UEs for data transmission on the DL, sidelink, and/or UL.

While communication between user equipments (UEs) (e.g., UE <NUM> of <FIG> and <FIG>) and base stations (BSs) (e.g., BSs <NUM> of <FIG> and <FIG>) may be referred to as the access link, and the access link may be provided via a cellular (Uu) interface, communication between devices may be referred to as the sidelink.

In some examples, the sidelink signals may be communicated using a licensed spectrum (unlike wireless local area networks (WLANs), which typically use an unlicensed spectrum).

<FIG> show diagrammatic representations of example vehicle to everything (V2X) systems, in accordance with certain aspects of the present disclosure. For example, the vehicles shown in <FIG> may communicate via sidelink channels and may perform sidelink channel state information (CSI) reporting as described herein.

V2X systems, provided in <FIG> provide two complementary transmission modes. A first transmission mode, shown by way of example in <FIG>, involves direct communications (for example, also referred to as sidelink communications) between participants in proximity to one another in a local area. A second transmission mode, shown by way of example in <FIG>, involves network communications through a network, which may be implemented over a Uu interface (for example, a wireless communication interface between a radio access network (RAN) and a UE).

Referring to <FIG>, a V2X system 500A (for example, including vehicle-to-vehicle (V2V) communications) is illustrated with two vehicles <NUM>, <NUM>. The first transmission mode may allow for direct communication between different participants in a given geographic location. As illustrated, a vehicle may have a wireless communication link <NUM> with an individual (i.e., vehicle to pedestrian (V2P)) (for example, via a UE) through a PC5 interface. Communications between vehicles <NUM> and <NUM> may also occur through a PC5 interface <NUM>. In a like manner, communication may occur from a vehicle <NUM> to other highway components (for example, roadside service unit <NUM>), such as a traffic signal or sign (i.e., vehicle to infrastructure (V2I)) through a PC5 interface <NUM>. With respect to each communication link illustrated in <FIG>, two-way communication may take place between elements, therefore each element may be a transmitter and a receiver of information. The V2X system <NUM> may be a self-managed system implemented without assistance from a network entity. A self-managed system may enable improved spectral efficiency, reduced cost, and increased reliability as network service interruptions do not occur during handover operations for moving vehicles. The V2X system may be configured to operate in a licensed or unlicensed spectrum, thus any vehicle with an equipped system may access a common frequency and share information. Such harmonized/common spectrum operations allow for safe and reliable operation.

<FIG> shows a V2X system 500B for communication between a vehicle <NUM> and a vehicle <NUM> through a network entity <NUM>. These network communications may occur through discrete nodes, such as a BS (for example, an eNB or gNB), that sends and receives information to and from (for example, relays information between) vehicles <NUM>, <NUM>. The network communications through vehicle to network (V2N) links <NUM> and <NUM> may be used, for example, for long range communications between vehicles, such as for communicating the presence of a car accident a distance ahead along a road or highway. Other types of communications may be sent by the node to vehicles, such as traffic flow conditions, road hazard warnings, environmental/weather reports, and service station availability, among other examples. Such data can be obtained from cloud-based sharing services.

As described above, V2V and V2X communications are examples of communications that may be transmitted via a sidelink. Other applications of sidelink communications may include public safety or service announcement communications, communications for proximity services, communications for UE-to-network relaying, device-to-device (D2D) communications, Internet of Everything (IoE) communications, Internet of Things (IoT) communications, mission-critical mesh communications, among other suitable applications. Generally, a sidelink may refer to a direct link between one subordinate entity (for example, UE1) and another subordinate entity (for example, UE2). As such, a sidelink may be used to transmit and receive a communication (also referred to herein as a "sidelink signal") without relaying the communication through a scheduling entity (for example, a BS), even though the scheduling entity may be utilized for scheduling or control purposes. In some examples, a sidelink signal may be communicated using a licensed spectrum (unlike wireless local area networks (WLANs), which typically use an unlicensed spectrum).

Various sidelink channels may be used for sidelink communications, including a physical sidelink discovery channel (PSDCH), a physical sidelink control channel (PSCCH), a physical sidelink shared channel (PSSCH), and a physical sidelink feedback channel (PSFCH). The PSDCH may carry discovery expressions that enable proximal devices to discover each other. The PSCCH may carry control signaling such as sidelink resource configurations and other parameters used for data transmissions, and the PSSCH may carry the data transmissions.

For the operation regarding PSSCH, a UE performs either transmission or reception in a slot on a carrier. A reservation or allocation of transmission resources for a sidelink transmission is typically made on a sub-channel of a frequency band for a period of a slot. NR sidelink supports for a UE a case where all the symbols in a slot are available for sidelink, as well as another case where only a subset of consecutive symbols in a slot is available for sidelink.

PSFCH may carry feedback such as CSI related to a sidelink channel quality. A sequence-based PSFCH format with one symbol (not including automatic gain control (AGC) training period) may be supported. The following formats may be possible: a PSFCH format based on PUCCH format <NUM> and a PSFCH format spanning all available symbols for sidelink in a slot.

<FIG> illustrates a diagrammatic representation of an example deployment <NUM> implementing sidelink communication (e.g., PC5) and cellular communication (Uu), in accordance with certain aspects of the present disclosure. In certain aspects, the deployment <NUM> may be understood to be a more general version of the systems 500A and 500B of <FIG>.

As shown, multiple UEs (e.g., UE1, UE2, UE3, and UE4) can have direct (e.g., sidelink) communication with one another without needing to go through a BS (e.g., the gNB). Further, this can be accomplished even for UEs that are out of coverage from a gNB (e.g., UE4). In some cases, the UEs (e.g., UE1, UE2, UE3, and UE4) communicating via sidelink may use sidelink discontinuous reception (DRX) to save power.

Aspects of the present disclosure provide techniques that may help coordinate retransmissions for sidelink communications between UEs, such as those shown in <FIG>, while in DRX modes. For example, such UEs may implement of hybrid automatic repeat request (HARQ) timer and a retransmission during sidelink DRX operations to manage retransmission of failed transmissions.

In general, timer-based sidelink DRX is used in sidelink radio resource control (RRC) connected mode. In some systems (e.g., Release <NUM>), RRC connected mode may be the only mode in which timer-based sidelink DRX is supported. Sidelink DRX may be applied to both regular data transmission and paging messages.

Sidelink DRX operation typically involves ON slots and OFF slots. During the ON slots, the UE is in an active state where the UE may transmit and/or monitor for signals. In OFF slots, the UE enters a sleep (or inactive) state during which the UE does not monitor a physical sidelink control channel (PSCCH). Additionally, a UE may not be permitted to interrupt the inactive state to transmit to another UE. This is different from a typical cellular (Uu) interface, as the destination UE is not monitoring PSCCH. Further, it may be assumed that a source UE and a destination UE have aligned active (common ON) times. That is, the source UE and/or the destination UE may be active during a common ON period.

Sidelink DRX generally helps UEs save on power consumption. Further, a UE may return to an active state temporarily after (a first/initial) data transmission/reception to perform a potential data retransmission of the first data transmission. Accordingly, certain aspects are generally directed to proposals for handling of timers that correspond to such data retransmissions during sidelink DRX.

<FIG> is a flow diagram illustrating example operations <NUM> for wireless communication by a transmitter UE, in accordance with certain aspects of the present disclosure. The operations <NUM> may be performed, for example, by a transmitter UE (e.g., UE 120a or 120b of <FIG> or UE 120a of <FIG>) to handle timers in sidelink communication with a receiver UE. The operations <NUM> may be implemented as software components that are executed and run on one or more processors (e.g., controller/processor <NUM> of <FIG>). Further, the transmission and reception of signals by the transmitter UE in operations <NUM> may be enabled, for example, by one or more antennas (e.g., antennas <NUM> of <FIG>). In certain aspects, the transmission and/or reception of signals by the transmitter UE may be implemented via a bus interface of one or more processors (e.g., controller/processor <NUM> of <FIG>) obtaining and/or outputting signals.

The operations <NUM> begin, at <NUM>, by transmitting a first repetition of a physical sidelink shared channel (PSSCH) to receiver UE prior to entering an inactive state, while the transmitter UE is operating in a sidelink DRX mode.

At <NUM>, the transmitter UE returns to an active state to monitor for acknowledgment feedback from the receiver UE, wherein the return is based on a first timer relative to an end of the first repetition of the PSSCH.

At <NUM>, the transmitter UE remains in the active state for a duration defined by a second timer. In some cases, the first and second timers are set such that transmitter UE transmits a second repetition of the PSSCH when the receiver UE is in an active state and/or such that the transmitter UE is in an active state when the receiver UE is configured to send acknowledgment feedback.

At <NUM>, the transmitter UE takes one or more actions depending on whether the transmitter UE receives acknowledgment feedback during the duration indicating failed reception of the first repetition of the PSSCH by the receiver UE. For example, the transmitter UE may return to the inactive state unless the UE receives acknowledgment feedback during the duration indicating failed reception of the first repetition of the PSSCH by the receiver UE. As another example, the transmitter UE may transmit a second repetition of the PSSCH when the UE receives acknowledgment feedback during the duration indicating failed reception of the first repetition of the PSSCH by the receiver UE.

<FIG> is a flow diagram illustrating example operations <NUM> for wireless communication by a receiver UE, in accordance with certain aspects of the present disclosure. The operations <NUM> may be performed, for example, by a receiver UE (e.g., UE 120a or 120b of <FIG> or UE 120a of <FIG>) to handle timers in sidelink communication with a transmitter UE. The operations <NUM> may be implemented as software components that are executed and run on one or more processors (e.g., controller/processor <NUM> of <FIG>). Further, the transmission and reception of signals by the receiver UE in operations <NUM> may be enabled, for example, by one or more antennas (e.g., antennas <NUM> of <FIG>). In certain aspects, the transmission and/or reception of signals by the receiver UE may be implemented via a bus interface of one or more processors (e.g., controller/processor <NUM> of <FIG>) obtaining and/or outputting signals. In some cases, the operations <NUM> performed by the receiver UE may be complementary to the operations <NUM> of <FIG> performed by the transmitter UE.

The operations <NUM> begin, at <NUM>, by monitoring for a first repetition of a PSSCH from a transmitter UE prior to entering an inactive state, while the receiver UE is operating in a sidelink DRX mode.

At <NUM>, the receiver UE transmits acknowledgment feedback to the transmitter UE indicating failed reception of the first repetition of the PSSCH.

At <NUM>, the receiver UE returns to an active state after transmitting the acknowledgment feedback, wherein the return is based on a first timer relative to an end of the acknowledgment feedback transmission.

At <NUM>, the receiver UE remains in the active state for a duration defined by a second timer to monitor for a second repetition of the PSSCH. In some cases, the first and second timers are set such that the receiver UE is in an active state when the transmitter UE transmits the second repetition of the PSSCH and/or such that the receiver UE is configured to send the acknowledgment feedback when the transmitter UE is in an active state.

Operations <NUM> and <NUM> of <FIG> and <FIG> may be understood with reference to <FIG>, which show exemplary transmission timelines 900A and 900B illustrating handling of HARQ and retransmission timers during sidelink DRX operations, in accordance with certain aspects of the present disclosure. In other words, the timeline 900A corresponds to a transmitter UE (e.g., the transmitter UE performing the operations <NUM> of <FIG>), while the timeline 900B corresponds to a receiver UE (e.g., the receiver UE performing the operations <NUM> of <FIG>).

In certain aspects, the HARQ timer (e.g., sl-drx-HARQ-RTT-TimerTX) of the timeline 900A may specify the timing of a return to an active state (from an inactive state) relative to the end of a first repetition of a PSSCH transmission. When the transmitter UE returns to the active state (e.g., the sl-drx-HARQ-RTT-TimerTX has expired), the transmitter UE remains active for a period defined by the retransmission timer (e.g., sl-drx-RetransmissionTimerTX). In certain aspects, the transmitter UE may return to an inactive state if a retransmission request (e.g., a negative acknowledgement message (NACK)) is not received during this time window. As used herein, HARQ timer (of the transmitter UE and the receiver UE) and sl-drx-HARQ-RTT-TimerTX/sl-drx-HARQ-RTT-TimerRX may be used interchangeably. Further, as used herein, retransmission timer (of the transmitter UE and the receiver UE) and drx-RetransmissionTimerTX/drx-RetransmissionTimerRX may be used interchangeably. In certain aspects, the HARQ timer and/or the retransmission timer may be configured via signaling from a network entity (e.g., radio resource control (RRC) signaling from a network entity such as the gNB <NUM> of <FIG>). In some cases, the HARQ timer and/or the retransmission timer may be configured via sidelink DRX configuration signaling between Tx and Rx UEs to share their respective sidelink DRX timer configuration values.

Referring now to the timeline 900B, if a receiver UE sends a NACK for the data on PSCCH, the receiver UE returns to an active state to receive the retransmission from the transmitter UE. As shown, the timer sl-drx-HARQ-RTT-TimerRX starts after the receiver UE has transmitted the NACK on PSCCH to the transmitter UE. Additionally, as shown, the receiver UE remains active for a period defined by the timer sl-drx-RetransmissionTimerRX while waiting to receive the retransmission.

<FIG> are exemplary transmission timelines 1000A and 1000B illustrating handling of HARQ and retransmission timers based on whether a transmission was received successfully, in accordance with certain aspects of the present disclosure.

As shown in the timeline 1000A, if the data reception at a receiver UE is successful, the receiver UE sends an ACK message to the transmitter UE, then both UEs return to the inactive state (e.g., the TX UE may return to inactive after expiration of the sl-drx-RetransmissionTimerTX timer). Further, the timers sl-drx-HARQ-RTT-TimerTX and sl-drx-RetransmissionTimerTX of the transmitter UE may be set so that the transmitter UE is active when the receiver UE sends the ACK message.

Referring now to the timeline 1000B, if the data reception at the receiver UE fails, the receiver UE sends a NACK message to the transmitter UE. In response, the transmitter UE retransmits the data, during the duration defined by the sl-drx-RetransmissionTimerRX timer. In other words, the timers sl-drx-HARQ-RTT-TimerTX and sl-drx-RetransmissionTimerTX of the transmitter UE may be set so that the transmitter UE is active when the receiver UE sends the NACK message. The timers sl-drx-HARQ-RTT-TimerRX and sl-drx-RetransmissionTimerRX of the receiver UE are set so that the receiver UE is active when the transmitter UE retransmits the data.

<FIG> are exemplary transmission timelines 1100A and 1100B illustrating extending of HARQ and/or retransmission timers through a common OFF period of sidelink DRX operations, in accordance with certain aspects of the present disclosure.

As shown in the timeline 1100A, the timers sl-drx-HARQ-RTT-TimerTX of the transmitter UE and sl-drx-HARQ-RTT-TimerRX of the receiver UE may extend in to a common OFF period. In this case, a common OFF period may be understood to be a period during which both the transmitter UE and the receiver UE are in a DRX OFF state. Thus, the HARQ timer for each UE continues during the common OFF period, and each UE returns to an active state when the HARQ timers expire. Further, the UEs remain active before each respective retransmission timer expires.

Similarly, as shown in the timeline 1100B, the retransmission timers sl-drx-RetransmissionTimerTX and sl-drx-RetransmissionTimerRX of the transmitter UE and the receiver UE, respectively, extend/continue into the common OFF period. That is, each UE returns to the active state when the respective HARQ timers expire and remains active before retransmission timers expire and into the common OFF period.

<FIG> are exemplary transmission timelines 1200A and 1200B illustrating pausing of HARQ and/or retransmission timers through a common OFF period of sidelink DRX operations, in accordance with certain aspects of the present disclosure.

As shown in the timeline 1200A, the HARQ timers are paused during the common OFF period. That is, the HARQ timers are paused, but not stopped/terminated during the common OFF period. Accordingly, the HARQ timers are resumed at the beginning of the next common ON, and each UE returns to an active state when the HARQ timers expire, and remains active before its retransmission timer expires.

As shown in the timeline 1200B, the retransmission timers are paused (but not stopped/terminated) during the common OFF period, and resumed at the beginning of the next common ON duration. As described above, the UEs return to the active state when each respective HARQ timer expires, and each UE remains active before its retransmission timer expires.

<FIG> are exemplary transmission timelines 1300A and 1300B illustrating expiration of HARQ and/or retransmission timers prior to a common OFF period, in accordance with certain aspects of the present disclosure.

As shown in the timeline 1300A, the HARQ timer for each of the transmitter UE and the receiver UE expires at the beginning of common OFF, and the short/long sidelink DRX cycle starts at a subsequent (not shown) common ON duration. As shown in the timeline 1300B, the retransmission timer of each of the transmitter UE and the receiver UE expires at the beginning of common OFF, and the short/long sidelink DRX cycle starts at a subsequent (not shown) common ON duration (during which the TX UE and/or RX UE is on). In each of the cases illustrated in the timelines 1300A and 1300B, the transmission/reception of the data fails.

<FIG> illustrates a communications device <NUM> that may include various components (e.g., corresponding to means-plus-function components) configured to perform operations for the techniques disclosed herein, such as the operations <NUM> illustrated in <FIG>.

Communications device <NUM> includes a processing system <NUM> coupled to a transceiver <NUM> (e.g., a transmitter and/or a receiver). Transceiver <NUM> is configured to transmit and receive signals for the communications device <NUM> via an antenna <NUM>, such as the various signals as described herein.

Processing system <NUM> includes a processor <NUM> coupled to a computer-readable medium/memory <NUM> via a bus <NUM>. In certain aspects, computer-readable medium/memory <NUM> is configured to store instructions (e.g., computer-executable code) that when executed by the processor <NUM>, cause the processor <NUM> to perform the operations <NUM> illustrated in <FIG>, or other operations for handling timers in sidelink discontinuous reception (DRX) communication. In certain aspects, the processor <NUM> can include one or more components of UE 120a with reference to <FIG> such as controller/processor <NUM>, transmit processor <NUM>, receive processor <NUM>, and/or the like. Additionally, in certain aspects, computer-readable medium <NUM> can include one or more components of UE 120a with reference to <FIG> such as, for example, memory <NUM>, and/or the like.

Computer-readable medium/memory <NUM> stores code <NUM> for transmitting; code <NUM> for returning; code <NUM> for remaining; code <NUM> for taking; code <NUM> for allowing; code <NUM> for pausing; and code <NUM> for resuming.

Code <NUM> for transmitting includes code for transmitting a first repetition of a physical sidelink shared channel (PSSCH) transmission to a receiver UE prior to entering an inactive state, while the transmitter UE is operating in a sidelink discontinuous reception (DRX) mode.

Code <NUM> for returning includes code for returning to an active state to monitor for acknowledgment feedback from the receiver UE, wherein the return is based on a first timer relative to an end of the first repetition of the PSSCH.

Code <NUM> for remaining includes code for remaining in the active state for a duration defined by a second timer.

Code <NUM> for taking includes code for taking one or more actions depending on whether the transmitter UE receives acknowledgment feedback during the duration indicating failed reception of the first repetition of the PSSCH by the receiver UE.

In some cases, code <NUM> for allowing may include code for allowing at least one of the first or second timers to run during a common OFF period during which both the transmitter UE and the receiver UE are in a DRX OFF state.

Code <NUM> for pausing includes code for pausing at least one of the first or second timers during a common OFF period during which both the transmitter UE and the receiver UE are in a DRX OFF state.

Code <NUM> for resuming includes code for resuming at least one of the first or second timers during a subsequent common ON period during which at least one of the transmitter UE or the receiver UE is in a DRX ON state.

The processor <NUM> has circuitry configured to implement the code stored in the computer-readable medium/memory <NUM>. The processor <NUM> includes circuitry <NUM> for transmitting; circuitry <NUM> for returning; circuitry <NUM> for remaining; circuitry <NUM> for taking; circuitry <NUM> for allowing; circuitry <NUM> for pausing; and circuitry <NUM> for resuming.

Circuitry <NUM> for transmitting includes circuitry for transmitting a first repetition of a PSSCH transmission to a receiver UE prior to entering an inactive state, while the transmitter UE is operating in a sidelink DRX mode.

Circuitry <NUM> for returning includes circuitry for returning to an active state to monitor for acknowledgment feedback from the receiver UE, wherein the return is based on a first timer relative to an end of the first repetition of the PSSCH.

Circuitry <NUM> for remaining includes code for remaining in the active state for a duration defined by a second timer.

Circuitry <NUM> for taking includes circuitry for taking one or more actions depending on whether the transmitter UE receives acknowledgment feedback during the duration indicating failed reception of the first repetition of the PSSCH by the receiver UE.

In some cases, circuitry <NUM> for allowing may include circuitry for allowing at least one of the first or second timers to run during a common OFF period during which both the transmitter UE and the receiver UE are in a DRX OFF state.

Circuitry <NUM> for pausing includes circuitry for pausing at least one of the first or second timers during a common OFF period during which both the transmitter UE and the receiver UE are in a DRX OFF state.

Circuitry <NUM> for resuming includes circuitry for resuming at least one of the first or second timers during a subsequent common ON period during which at least one of the transmitter UE or the receiver UE is in a DRX ON state.

The operations <NUM> illustrated in <FIG>, as well as other operations described herein, are implemented by one or more means-plus-function components. For example, in some cases, such operations may be implemented by means for identifying and means for using.

In some cases, means for returning, means for remaining, means for taking, means for allowing, means for pausing, and means for resuming includes a processing system, which may include one or more processors, such as the receive processor <NUM>, the transmit processor <NUM>, the TX MIMO processor <NUM>, and/or the controller/processor <NUM> of the UE 120a and/or UE 120b illustrated in <FIG> and/or the processing system <NUM> of the communication device <NUM> in <FIG>.

Processing system <NUM> includes a processor <NUM> coupled to a computer-readable medium/memory <NUM> via a bus <NUM>. In certain aspects, computer-readable medium/memory <NUM> is configured to store instructions (e.g., computer-executable code) that when executed by the processor <NUM>, cause the processor <NUM> to perform the operations <NUM> illustrated in <FIG>, or other operations for handling timers in sidelink discontinuous reception (DRX) communication. In certain aspects, the processor <NUM> can include one or more components of UE 120a with reference to <FIG> such as controller/processor <NUM>, transmit processor <NUM>, receive processor <NUM>, and/or the like. Additionally, in certain aspects, computer-readable medium <NUM> can include one or more components of UE 120a (and/or UE 120b) with reference to <FIG> such as, for example, memory <NUM>, and/or the like.

Computer-readable medium/memory <NUM> stores code <NUM> for monitoring; code <NUM> for transmitting; code <NUM> for returning; code <NUM> for remaining; code <NUM> for allowing; code <NUM> for pausing; and code <NUM> for resuming.

Code <NUM> for monitoring includes code for monitoring for a first repetition of a PSSCH from a transmitter UE prior to entering an inactive state, while the receiver UE is operating in a sidelink DRX mode.

Code <NUM> for transmitting includes code for transmitting acknowledgment feedback to the transmitter UE indicating failed reception of the first repetition of the PSSCH.

Code <NUM> for returning includes code for returning to an active state after transmitting the acknowledgment feedback, wherein the return is based on a first timer relative to an end of the acknowledgment feedback transmission.

Code <NUM> for remaining includes code for remaining in the active state for a duration defined by a second timer to monitor for a second repetition of the PSSCH.

The processor <NUM> has circuitry configured to implement the code stored in the computer-readable medium/memory <NUM>. The processor <NUM> includes circuitry <NUM> for monitoring; circuitry <NUM> for transmitting; circuitry <NUM> for returning; circuitry <NUM> for remaining; circuitry <NUM> for allowing; circuitry <NUM> for pausing; and circuitry <NUM> for resuming.

Circuitry <NUM> for monitoring includes circuitry for monitoring for a first repetition of a PSSCH from a transmitter UE prior to entering an inactive state, while the receiver UE is operating in a sidelink DRX mode.

Circuitry <NUM> for transmitting includes circuitry for transmitting acknowledgment feedback to the transmitter UE indicating failed reception of the first repetition of the PSSCH.

Circuitry <NUM> for returning includes circuitry for returning to an active state after transmitting the acknowledgment feedback, wherein the return is based on a first timer relative to an end of the acknowledgment feedback transmission.

Circuitry <NUM> for remaining includes circuitry for remaining in the active state for a duration defined by a second timer to monitor for a second repetition of the PSSCH.

In some cases, means for returning, means for remaining, means for allowing, means for pausing, and means for resuming includes a processing system, which may include one or more processors, such as the receive processor <NUM>, the transmit processor <NUM>, the TX MIMO processor <NUM>, and/or the controller/processor <NUM> of the UE 120a (and/or UE 120b) illustrated in <FIG> and/or the processing system <NUM> of the communication device <NUM> in <FIG>.

The preceding description provides examples of utilizing physical resource blocks (PRBs) that do not belong to a sub-channel in sidelink, and is not limiting of the scope, applicability, or examples set forth in the claims. In addition, the scope of the disclosure is intended to cover such an apparatus or method that is practiced using other structure, functionality, or structure and functionality in addition to, or other than, the various aspects of the disclosure set forth herein.

The techniques described herein may be used for various wireless communication technologies, such as <NUM> (e.g., <NUM> NR), 3GPP Long Term Evolution (LTE), code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), orthogonal frequency division multiple access (OFDMA), single-carrier frequency division multiple access (SC-FDMA), time division synchronous code division multiple access (TD-SCDMA), and other networks.

NR access (e.g., <NUM> technology) may support various wireless communication services, such as enhanced mobile broadband (eMBB) targeting wide bandwidth (e.g., <NUM> or beyond), millimeter wave (mmW) targeting high carrier frequency (e.g., <NUM> or beyond), massive machine type communications MTC (mMTC) targeting non-backward compatible MTC techniques, and/or mission critical targeting ultra-reliable low-latency communications (URLLC).

Generally, where there are operations illustrated in figures, those operations may have corresponding counterpart means-plus-function components. For example, various operations shown in <FIG> and <FIG> may be performed by various processors shown in <FIG>, such as processors <NUM>, <NUM>, <NUM>, and/or controller/processor <NUM> of the UE 120a.

In the case of a UE <NUM> (see <FIG>), a user interface (e.g., keypad, display, mouse, joystick, etc.) may also be connected to the bus.

For example, instructions for performing the operations described herein and illustrated in <FIG> and <FIG>.

Claim 1:
A method for wireless communications performed by a transmitter user equipment, UE, the method comprising:
transmitting (<NUM>) a first repetition of a physical sidelink shared channel, PSSCH, transmission to a receiver UE prior to entering an inactive state, while the transmitter UE is operating in a sidelink discontinuous reception, DRX, mode;
returning (<NUM>) to an active state to monitor for acknowledgment feedback from the receiver UE, wherein the return is based on a first timer relative to an end of the first repetition of the PSSCH;
remaining (<NUM>) in the active state for a duration defined by a second timer; and
taking (<NUM>) one or more actions depending on whether the transmitter UE receives acknowledgment feedback during the duration indicating failed reception of the first repetition of the PSSCH by the receiver UE;
characterized in that the method further comprises:
pausing at least one of the first or second timers during a common OFF period during which both the transmitter UE and the receiver UE are in a DRX OFF state; and
resuming at least one of the first or second timers during a subsequent common ON period during which at least one of the transmitter UE or the receiver UE is in a DRX ON state.