Connected mode discontinuous reception (c-DRX) enhancement with wake-up signals for

Abstract

Apparatuses, methods, and computer-readable media for connected mode discontinuous reception (DRX) enhancement with wake-up signals for sidelink communications are disclosed herein. A receiver user equipment (UE) may receive a sidelink DRX configuration that configures the receiver UE with a first sidelink DRX configuration or a second sidelink DRX configuration, the first sidelink DRX configuration configures the receiver UE to transition to a sleep state when a sidelink WUS is indicated and the second sidelink DRX configuration configures the receiver UE to transition to a wake-up state when the sidelink WUS is indicated. The receiver UE transitions to the sleep state in a second DRX cycle based on receiving the sidelink WUS and the first sidelink DRX configuration within a sidelink WUS monitoring occasion, or transitions to the wake state based on receiving the sidelink WUS and the second sidelink DRX configuration within the sidelink WUS monitoring occasion.

Description

Background Art Technical Field

[0001] The present disclosure generally relates to communication systems, and more particularly to enhanced connected mode discontinuous reception (C-DRX) using wake-up signals for sidelink communication.

[0002] Introduction

[0003] Wireless communication systems are widely deployed to provide various telecommunication services such as telephony, video, data, messaging, and broadcasting. A typical wireless communication system may employ multiple access technologies capable of supporting communication with multiple users by sharing available system resources. Examples of such multiple access technologies include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, orthogonal frequency division multiple access (OFDMA) systems, single carrier frequency division multiple access (SC-FDMA) systems, and time division synchronous code division multiple access (TD-SCDMA) systems.

[0004] These multiple access technologies have been adopted in various telecommunication standards to provide a common protocol that enables different wireless devices to communicate at the urban, national, regional, and even global levels. An example telecommunication standard is 5G New Radio (NR). 5G NR is part of the ongoing evolution of mobile broadband promulgated by the Third Generation Partnership Project (3GPP) to meet new requirements associated with latency, reliability, security, scalability (e.g., related to the Internet of Things (IoT)), and other requirements. 5G NR includes services associated with enhanced mobile broadband (eMBB), massive machine type communication (mMTC), and ultra-reliable low latency communication (URLLC). Some aspects of 5G NR may be based on the 4G Long Term Evolution (LTE) standard. Further improvements to 5G NR technology are needed.

[0005] In addition, these improvements may also be applicable to other multiple access technologies and telecommunication standards that employ these technologies. For example, some aspects of wireless communication include direct communication between devices such as device-to-device (D2D), vehicle-to-everything (V2X), etc. Further improvements to this direct communication between devices are needed. Improvements related to direct communication between devices may also be applicable to other multiple access technologies and telecommunication standards that employ these technologies. Summary of the Invention

[0006] A simplified review of one or more aspects is presented below to provide a basic understanding of these aspects. This summary of the invention is not an extensive overview of all contemplated aspects, and is neither intended to identify key or critical elements of all aspects nor to describe the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form as a prelude to the more detailed description that is presented later.

[0007] Describes various aspects and features related to power saving in a wireless communication system. Some aspects described herein allow for supporting multiple power and / or spectrum efficient modes / configurations in a wireless communication device (such as an IoT device for example) to facilitate low power operation and / or reduce power consumption.

[0008] In Uu link power saving techniques, a wake-up signal (WUS) based on a downlink control channel may configure a configurable offset before a discontinuous reception (DRX) active duration cycle to achieve improvements in power saving. A connected mode DRX (C-DRX) mechanism is also introduced in sidelink communication to save power. However, there may be unnecessary wake-up events in sidelink communication, which may adversely affect the power efficiency during C-DRX operation.

[0009] The present subject technology provides for enhancing C-DRX by utilizing WUS for sidelink communication to help avoid such unnecessary wake-up events. For example, a receiving UE may be configured with a first sidelink DRX configuration that configures the receiving UE to transition to a sleep state when a sidelink WUS is indicated, or with a second sidelink DRX configuration that configures the receiving UE to transition to a wake-up state when a sidelink WUS is indicated. Upon detecting the WUS, the receiving UE transitions to the sleep state based on receiving the sidelink WUS within a sidelink WUS monitoring occasion, and the receiving UE is configured with the first sidelink DRX configuration. Alternatively, the receiving UE transitions to the wake-up state based on receiving the sidelink WUS within a sidelink WUS monitoring occasion, and the receiving UE is configured with the second sidelink DRX configuration.

[0010] In one aspect of the present disclosure, a method, a computer-readable medium, and a device are provided. The device may be a receiving user equipment (UE). The device is configured to receive a sidelink discontinuous reception (DRX) configuration from a transmitting UE via a transceiver. The device is further configured to determine whether to configure the receiving UE with a first sidelink DRX configuration or a second sidelink DRX configuration, where the first sidelink DRX configuration configures the receiving UE to transition to a sleep state when a sidelink wake-up signal (WUS) is indicated, and the second sidelink DRX configuration configures the receiving UE to transition to a wake-up state when a sidelink WUS is indicated. The device is further configured to determine whether a sidelink WUS is received within a sidelink WUS monitoring occasion in a first DRX cycle based on the sidelink DRX configuration. The device is further configured to transition to a sleep state in a second DRX cycle based on receiving the sidelink WUS within the sidelink WUS monitoring occasion and the sidelink DRX configuration configuring the receiving UE with the first sidelink DRX configuration. The device is further configured to transition to a wake-up state in a second DRX cycle based on receiving the sidelink WUS within the sidelink WUS monitoring occasion and the sidelink DRX configuration configuring the receiving UE with the second sidelink DRX configuration.

[0011] In one aspect of the present disclosure, a method, a computer-readable medium, and a device are provided. The device may be a transmitting UE. The device is configured to determine a first sidelink DRX configuration to configure a receiving UE to transition to a sleep state when a sidelink WUS is indicated, and to determine a second sidelink DRX configuration to configure the receiving UE to transition to a wake-up state when a sidelink WUS is indicated. The device is further configured to send, via a transceiver, a sidelink DRX configuration to the receiving UE to configure the receiving UE with the first sidelink DRX configuration or the second sidelink DRX configuration. The device is further configured to send a sidelink WUS to the receiving UE via the transceiver within a sidelink WUS monitoring occasion in a first DRX cycle based on the sidelink DRX configuration.

[0012] To achieve the foregoing and related purposes, one or more aspects include the features described comprehensively hereinafter and particularly pointed out in the claims. The following description and the drawings set forth in detail some illustrative features of one or more aspects. However, these features are only indicative of some of the various ways in which the principles of the various aspects may be employed, and this specification is intended to include all such aspects and their equivalents. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 is a diagram illustrating an example of a wireless communication system and an access network.

[0014] Figure 2A 、 Figure 2B 、 Figure 2C andFigure 2D It is a diagram illustrating examples of a first 5G / NR frame, DL channels within a 5G / NR subframe, a second 5G / NR frame, and UL channels within a 5G / NR subframe respectively.

[0015] Figure 3 It illustrates an example aspect of a sidelink slot structure.

[0016] Figure 4 It is a diagram illustrating examples of a base station and a user equipment (UE) in an access network.

[0017] Figure 5 It illustrates an example of sidelink communication between wireless devices according to one or more aspects of the present disclosure.

[0018] Figure 6 It illustrates an example discontinuous reception (DRX) cycle at the PC-5 interface.

[0019] Figure 7 It illustrates an example of sidelink communication between wireless devices with enhanced connected-mode discontinuous reception (C-DRX) using a wake-up signal for sidelink communication according to one or more aspects of the present disclosure.

[0020] Figure 8 It is a diagram illustrating an example of a DRX cycle with a wake-up signal (WUS) monitoring occasion according to one or more aspects of the present disclosure.

[0021] Figure 9 It is a diagram illustrating another example of a DRX cycle with sidelink control information (SCI) transmitted during a wake-up signal (WUS) monitoring occasion according to one or more aspects of the present disclosure.

[0022] Figure 10A It is a diagram illustrating an example of a DRX cycle with a WUS monitoring occasion according to one or more aspects of the present disclosure.

[0023] Figure 10B It is a diagram illustrating another example of a DRX cycle with SCI transmitted during a WUS monitoring occasion embedding a DRX-on duration instance according to one or more aspects of the present disclosure.

[0024] Figure 11A It is a diagram illustrating an example of a sidelink WUS monitoring occasion embedding a DRX-on duration according to one or more aspects of the present disclosure.

[0025] Figure 11B It is a diagram illustrating an example of a sidelink WUS monitoring occasion outside a DRX-on duration according to one or more aspects of the present disclosure.

[0026] Figure 12 FIG. is an illustration of an example of a DRX cycle having a sidelink WUS associated with multiple consecutive DRX on-duration instances in accordance with one or more aspects of the present disclosure.

[0027] Figure 13 FIG. is an illustration of an example of a DRX cycle having a physical sidelink feedback channel (PSFCH) transmitted in a WUS monitoring occasion in accordance with one or more aspects of the present disclosure.

[0028] Figure 14 FIG. is an illustration of another example of a DRX cycle having a PSFCH transmitted in a WUS monitoring occasion in accordance with one or more aspects of the present disclosure.

[0029] Figure 15 FIG. is an illustration of yet another example of a DRX cycle having a PSFCH transmitted in a WUS monitoring occasion in accordance with one or more aspects of the present disclosure.

[0030] Figure 16 FIG. is a flow diagram of a process for wireless communication supporting C-DRX enhancements with a wake-up signal for sidelink communication at a receiver UE in accordance with some aspects of the present disclosure.

[0031] Figure 17 FIG. is a flow diagram of a process for wireless communication supporting C-DRX enhancements with a wake-up signal for sidelink communication at a transmitter UE in accordance with some aspects of the present disclosure.

[0032] Figure 18 FIG. is an illustration of an example of a hardware implementation for an example apparatus. DETAILED DESCRIPTION

[0033] The detailed description set forth below in connection with the appended drawings is intended as a description of various configurations and is not intended to represent the only configurations in which the concepts described herein may be practiced. The detailed description includes specific details for the purpose of providing a thorough understanding of various concepts. However, it will be apparent to those skilled in the art that these concepts may be practiced without these specific details. In some instances, well-known structures and components are shown in block diagram form to avoid obscuring such concepts.

[0034] A User Equipment (UE) can be configured by a base station for Discontinuous Reception (DRX) mode. When there is no data to be sent in either direction between the UE and the base station, e.g., no uplink or downlink transmission, the UE can enter the DRX mode, where the UE can use sleep and wake-up cycles to discontinuously monitor the control channel. DRX saves battery power at the UE to improve power efficiency. Without DRX, the UE may monitor the control channel in each time slot / subframe to check for data for the UE. Continuous monitoring of the control channel poses a demand on the UE's battery power.

[0035] The DRX configuration can be configured by the network in Radio Resource Control (RRC) signaling from the base station (e.g., in the RRC connection setup request or RRC connection reconfiguration request). The DRX configuration can include the configuration of any one of a plurality of timers and values, e.g., on-duration timer, DRX inactivity timer, DRX DL retransmission timer, DRX UL retransmission timer, DRX long cycle, value of DRX start offset, DRX short cycle timer, and / or DRX short cycle, etc. The DRX cycle can include a periodic repetition of an on-duration and an off-duration during which the UE monitors the Physical Downlink Control Channel (PDCCH), and the off-duration can be referred to as a DRX opportunity. During the off-duration, the UE does not monitor the PDCCH. The UE can enter a sleep mode or a low-power mode, in which the UE minimizes power consumption by turning off the radio frequency (RF) function and not detecting communications from the base station.

[0036] As an example, the DRX inactivity timer can indicate the time (e.g., expressed in terms of Transmission Time Interval (TTI) duration) after the UE successfully decodes the PDCCH when the UE can enter the off-duration again. The on-duration timer can indicate the amount of time the UE monitors communications from the base station when the UE wakes up from the off-duration in the DRX cycle. For example, the on-duration timer can give the number of consecutive PDCCH subframes to be monitored / decoded when the UE wakes up from the off-duration of the DRX cycle. If at least one associated timer is running (e.g., DRX on-duration timer, DRX inactivity timer, and / or DRX retransmission timer) and the UE is monitoring communications from the base station, the UE can be considered to be in the DRX active time.

[0037] The Connected DRX (C-DRX) mechanism is introduced to reduce power consumption by allowing the UE to periodically enter a power saving mode (or sleep state), where the UE can turn off the main circuits when no packets are expected to arrive. However, the UE also wakes up periodically to monitor for any packet arrivals. To prevent any data loss, the UE and the network may need to have a predefined agreement regarding the periodic transitions of the UE between the sleep state and the wake state. Typically, the UE receives the DRX configuration parameters in a downlink Radio Resource Control (RRC) configuration message transmitted by the network.

[0038] The Wake-Up Signal (WUS) is introduced to further reduce the power consumption of the UE, where the WUS is a special downlink control signal (e.g., Physical Downlink Control Channel (PDCCH)) transmitted by the network before the DRX active duration to indicate whether the UE should stay active to receive new data or skip the current DRX active duration until the next DRX active duration. The WUS can be transmitted outside the DRX active duration by using the group common Downlink Control Information (DCI) with a Cyclic Redundancy Check (CRC) scrambled by a Radio Network Temporary Identifier (RNTI) (referred to as Power Saving RNTI (PS-RNTI)). The DCI can have a specified format (e.g., DCI format 2_6) that can carry one or more information blocks, where each information block is intended for a specific UE (e.g., block number 1, block number 2,......, block number N).

[0039] In the Uu link power saving technology, the PDCCH-based WUS is configured with a configurable offset before the DRX active duration cycle to achieve improvements in power saving. The C-DRX mechanism is also introduced in sidelink communication to save power. It may be desirable to improve the power efficiency during C-DRX operation while reducing the likelihood of unnecessary wake-up events in sidelink communication.

[0040] The present subject technology provides for facilitating C-DRX enhancement using WUS for sidelink communication. In some particular implementations, a receiving UE for facilitating C-DRX enhancement using WUS may receive a sidelink DRX configuration and determine whether the sidelink DRX configuration configures the receiving UE with a first sidelink DRX configuration or a second sidelink DRX configuration, where the first sidelink DRX configuration configures the receiving UE to transition to a sleep state when a sidelink WUS is indicated, and the second sidelink DRX configuration configures the receiving UE to transition to a wake state when a sidelink WUS is indicated. The UE may determine whether a sidelink WUS is received within a sidelink WUS monitoring occasion in a first DRX cycle based on the sidelink DRX configuration. The UE may also transition to a sleep state in a second DRX cycle based on receiving the sidelink WUS within the sidelink WUS monitoring occasion and the sidelink DRX configuration configuring the receiving UE with the first sidelink DRX configuration. The UE may also transition to a wake state in a second DRX cycle based on receiving the sidelink WUS within the sidelink WUS monitoring occasion and the sidelink DRX configuration configuring the receiving UE with the second sidelink DRX configuration.

[0041] Certain aspects of the telecommunications system will now be presented with reference to various apparatuses and methods. These apparatuses and methods will be described in the following detailed description and illustrated in the drawings by various blocks, components, circuits, processes, algorithms, etc. (collectively referred to as "elements"). These elements can be implemented using electronic hardware, computer software, or any combination thereof. Whether such elements are implemented as hardware or software depends on the particular application and design constraints imposed on the overall system.

[0042] As an example, an element, or any portion of an element, or any combination of elements can be implemented as a "processing system" that includes one or more processors. Examples of processors include a microprocessor, a microcontroller, a graphics processing unit (GPU), a central processing unit (CPU), an application processor, a digital signal processor (DSP), a reduced instruction set computing (RISC) processor, a system on a chip (SoC), a baseband processor, a field programmable gate array (FPGA), a programmable logic device (PLD), a state machine, gated logic, discrete hardware circuits, and other suitable hardware configured to perform the various functions described throughout the present disclosure. One or more processors in the processing system may execute software. Whether referred to as software, firmware, middleware, microcode, hardware description language, or other names, software should be broadly interpreted to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software components, applications, software applications, software packages, routines, subroutines, objects, executable files, execution threads, processes, functions, etc.

[0043] Thus, in one or more example embodiments, the described functionality may be implemented in hardware, software, or any combination thereof. If implemented in software, the functionality may be stored or encoded as one or more instructions or code on a computer-readable medium. Computer-readable media includes computer storage media. Storage media can be any available media that can be accessed by a computer. By way of example and not limitation, such computer-readable media can include random access memory (RAM), read-only memory (ROM), electrically erasable programmable ROM (EEPROM), optical disk storage, magnetic disk storage, other magnetic storage devices, combinations of the aforementioned types of computer-readable media, or any other medium that can be used to store computer-executable code in the form of instructions or data structures that can be accessed by a computer.

[0044] Figure 1 FIG. 4 is a diagram illustrating an example of a wireless communication system and an access network 100. The wireless communication system (which is also referred to as a wireless wide area network (WWAN)) includes base stations 102, UEs 104, an evolved packet core (EPC) 160, and another core network 190 (e.g., a 5G core (5GC)). The base stations 102 may include macro cells (high-power cellular base stations) and / or small cells (low-power cellular base stations). Macro cells include base stations. Small cells include femtocells, picocells, and microcells.

[0045] Base stations 102 configured for 4G LTE (collectively referred to as evolved universal mobile telecommunications system (UMTS) terrestrial radio access network (E-UTRAN)) may interface with the EPC 160 via a backhaul link 132 (e.g., an S1 interface). Base stations 102 configured for 5G NR (collectively referred to as next-generation RAN (NG-RAN)) may interface with the core network 190 via a backhaul link 184. Among other functions, the base stations 102 may perform one or more of the following functions: transfer of user data, radio channel encryption and decryption, integrity protection, header compression, mobility control functions (e.g., handover, dual connectivity), inter-cell interference coordination, connection establishment and release, load balancing, distribution of non-access stratum (NAS) messages, NAS node selection, synchronization, radio access network (RAN) sharing, multimedia broadcast multicast service (MBMS), subscriber and equipment tracking, radio access network information management (RIM), paging, positioning, and delivery of warning messages. The base stations 102 may communicate with each other directly or indirectly (e.g., via the EPC 160 or the core network 190) via a backhaul link 134 (e.g., an X2 interface). The backhaul link 134 may be wired or wireless.

[0046] Base station 102 can communicate wirelessly with UE 104. Each base station in base station 102 can provide communication coverage for a corresponding geographical coverage area 110. There may be overlapping geographical coverage areas 110. For example, small cell 102' may have a coverage area 110' that overlaps with the coverage area 110 of one or more macro base stations 102. A network including both small cells and macro cells may be referred to as a heterogeneous network. The heterogeneous network may also include a home evolved Node B (eNB) (HeNB), which may provide services to a restricted group called a closed subscriber group (CSG). The communication link 120 between base station 102 and UE 104 may include an uplink (UL) (also called a reverse link) transmission from UE 104 to base station 102 and / or a downlink (DL) (also called a forward link) transmission from base station 102 to UE 104. The communication link 120 may use multiple-input multiple-output (MIMO) antenna technology, including spatial multiplexing, beamforming, and / or transmit diversity. The communication link may pass through one or more carriers. For each carrier allocated in carrier aggregation with a total of up to Yx MHz (x component carriers) for transmission in each direction, base station 102 / UE 104 may use a spectrum with a bandwidth of up to Y MHz (e.g., 5 MHz, 10 MHz, 15 MHz, 20 MHz, 100 MHz, 400 MHz, etc.). These carriers may or may not be adjacent to each other. The allocation of carriers may be asymmetric with respect to DL and UL (e.g., more or fewer carriers may be allocated for DL compared to UL). The component carriers may include a primary component carrier and one or more secondary component carriers. The primary component carrier may be referred to as the primary cell (PCell) and the secondary component carriers may be referred to as secondary cells (SCells).

[0047] Some UEs 104 may use device-to-device (D2D) communication links 158 to communicate with each other. The D2D communication links 158 may use DL / UL WWAN spectrum. Some wireless communications may be directly exchanged between wireless devices based on the sidelink. The communication may be based on vehicle-to-everything (V2X) or other device-to-device (D2D) communications, such as proximity services (ProSe), etc. For example, the sidelink communication may be exchanged based on the PC5 interface. For example, the D2D communication link 158 may use one or more sidelink channels, such as the physical sidelink broadcast channel (PSBCH), the physical sidelink discovery channel (PSDCH), the physical sidelink shared channel (PSSCH), and the physical sidelink control channel (PSCCH). The D2D communication may be through various wireless D2D communication systems, such as, for example, FlashLinQ, WiMedia, Bluetooth, ZigBee, Wi-Fi based on the IEEE 802.11 standard, LTE, or NR.

[0048] In sidelink communication, a transmitting UE may indicate control information in multiple SCI parts. The SCI may indicate resources that the UE intends to use, such as for sidelink transmission. The UE may transmit a first part of the control information indicating information about resource reservation in the PSCCH region, and may transmit a second part of the control information in the PSSCH region. For example, a first-level control (e.g., SCI-1) may be transmitted on the PSCCH and may include information for resource allocation and information for decoding a second-level control (e.g., SCI-2). The second-level control (SCI-2) may be transmitted on the PSSCH and may include information for decoding data (SCH). Thus, the control information may be indicated by a combination of a first SCI part (e.g., SCI-1) included in the PSCCH region and a second SCI part (e.g., SCI-2) included in the PSSCH region. In other aspects, the control information may be indicated in the medium access control (MAC) control element (MAC-CE) part of the PSSCH.

[0049] Some examples of sidelink communication may include vehicle-based communication, such as vehicle-to-vehicle (V2V), vehicle-to-infrastructure (V2I) (e.g., from a vehicle-based communication device to a road infrastructure node, such as a roadside unit (RSU)), vehicle-to-network (V2N) (e.g., from a vehicle-based communication device to one or more network nodes, such as a base station), vehicle-to-pedestrian (V2P), cellular vehicle-to-everything (C-V2X), and / or combinations thereof and / or communication with other devices, which may be collectively referred to as V2X communication. As an example, in Figure 1 UE 104 (e.g., a transmitting vehicle user equipment (VUE) or other UE 104) may be configured to directly send a message to another UE 104. This communication may be based on V2X or other D2D communication, such as proximity services (ProSe), etc. V2X- and / or D2D-based communication may also be sent and received by other transmitting and receiving devices (such as roadside unit (RSU) 107, etc.). Aspects of this communication may be based on PC5 or sidelink communication, e.g., as described in the examples in Figure 3 Although the following description may provide examples of V2X / D2D communication related to 5G NR, the concepts described herein may apply to other similar domains, such as LTE, LTE-A, CDMA, GSM, and other wireless technologies.

[0050] In addition, although the present disclosure may focus on vehicle-to-pedestrian (V2P) communication and pedestrian-to-vehicle (P2V) communication, the concepts and aspects described herein may be applicable to other similar fields, such as D2D communication, IoT communication, vehicle-to-everything (V2X) communication, or other standards / protocols for communication in wireless / access networks.

[0051] The wireless communication system may further include a Wi-Fi access point (AP) 150 that communicates with a Wi-Fi station (STA) 152 via a communication link 154 in the 5 GHz unlicensed spectrum. When communicating in the unlicensed spectrum, the STA 152 / AP 150 may perform a clear channel assessment (CCA) before communication to determine whether the channel is available.

[0052] The small cell 102' may operate in licensed and / or unlicensed spectrum. When operating in the unlicensed spectrum, the small cell 102' may adopt NR and use the same 5 GHz unlicensed spectrum as that used by the Wi-Fi AP 150. The small cell 102' adopting NR in the unlicensed spectrum may improve the coverage of the access network and / or increase the capacity of the access network.

[0053] The base station 102, whether it is a small cell 102' or a large cell (e.g., a macro base station), may include an eNB, a gNodeB (gNB), or another type of base station. Some base stations, such as the gNB 180, may operate in the traditional sub-6 GHz spectrum, millimeter wave (mmW) frequencies, and / or near mmW frequencies to communicate with the UE 104. When the gNB 180 operates in mmW or near mmW frequencies, the gNB 180 may be referred to as a mmW base station. The extremely high frequency (EHF) is a part of the RF in the electromagnetic spectrum. The EHF has a range of 30 GHz to 300 GHz, with wavelengths between 1 millimeter and 10 millimeters. The radio waves in this band may be referred to as millimeter waves. The near mmW may extend down to a frequency of 3 GHz, with a wavelength of 100 millimeters. The super high frequency (SHF) band extends between 3 GHz and 30 GHz, which is also referred to as centimeter waves. Communication using the mmW / near mmW radio frequency band (e.g., 3 GHz - 300 GHz) has extremely high path loss and short distances. The mmW base station 180 may use beamforming 182 together with the UE 104 to compensate for the extremely high path loss and short distances.

[0054] Base station 180 may transmit beamformed signals to UE 104 in one or more transmission directions 182'. UE 104 may receive beamformed signals from base station 180 in one or more reception directions 182". UE 104 may also transmit beamformed signals to base station 180 in one or more transmission directions. Base station 180 may receive beamformed signals from UE 104 in one or more reception directions. Base station 180 / UE 104 may perform beam training to determine the optimal reception and transmission directions for each of base station 180 / UE 104. The transmission direction and reception direction of base station 180 may be the same or may not be the same. The transmission direction and reception direction of UE 104 may be the same or may not be the same.

[0055] EPC 160 may include a Mobility Management Entity (MME) 162, other MMEs 164, Serving Gateway 166, Multimedia Broadcast Multicast Service (MBMS) Gateway 168, Broadcast Multicast Service Center (BM-SC) 170, and Packet Data Network (PDN) Gateway 172. MME 162 may communicate with a Home Subscriber Server (HSS) 174. MME 162 is a control node that processes signaling between UE 104 and EPC 160. Generally, MME 162 provides bearer and connection management. All user Internet Protocol (IP) packets are passed through Serving Gateway 166, which itself is connected to PDN Gateway 172. PDN Gateway 172 provides UE IP address allocation and other functions. PDN Gateway 172 and BM-SC 170 are connected to IP services 176. IP services 176 may include the Internet, intranet, IP Multimedia Subsystem (IMS), PS streaming services, and / or other IP services. BM-SC 170 may provide functions for MBMS user service configuration and delivery. BM-SC 170 may serve as an entry point for content provider MBMS transmissions, may be used to authorize and initiate MBMS bearer services in a Public Land Mobile Network (PLMN), and may be used to schedule MBMS transmissions. MBMS Gateway 168 may be used to distribute MBMS traffic to base stations 102 belonging to a Multicast Broadcast Single Frequency Network (MBSFN) area for a particular broadcast service, and may be responsible for session management (start / stop) and for collecting eMBMS-related charging information.

[0056] The core network 190 may include an Access and Mobility Management Function (AMF) 192, other AMFs 193, a Session Management Function (SMF) 194, and a User Plane Function (UPF) 195. The AMF 192 may communicate with a Unified Data Management (UDM) 196. The AMF 192 is a control node that processes signaling between the UE 104 and the core network 190. Generally speaking, the AMF 192 provides QoS flow and session management. All user Internet Protocol (IP) packets are transmitted through the UPF 195. The UPF 195 provides UE IP address allocation and other functions. The UPF 195 is connected to an IP service 197. The IP service 197 may include the Internet, an intranet, an IP Multimedia Subsystem (IMS), a PS streaming media service, and / or other IP services.

[0057] The base station may also be referred to as a gNB, Node B, evolved Node B (eNB), access point, base station transceiver, radio base station, radio transceiver, transceiver function, Basic Service Set (BSS), Extended Service Set (ESS), Transmission and Reception Point (TRP), or some other suitable term. The base station 102 provides an access point to the EPC 160 or the core network 190 for the UE 104. Examples of the UE 104 include a cellular phone, a smart phone, a Session Initiation Protocol (SIP) phone, a laptop computer, a Personal Digital Assistant (PDA), a satellite radio, a Global Positioning System, a multimedia device, a video device, a digital audio player (e.g., an MP3 player), a camera, a game console, a tablet computer, a smart device, a wearable device, a vehicle, a meter, a gas pump, a large or small kitchen appliance, a healthcare device, an implant, a sensor / actuator, a display, or any other device with similar functionality. Some of the UEs in the UE 104 may be referred to as IoT devices (e.g., a parking meter, a gas pump, a toaster, a vehicle, a heart monitor, etc.). The UE 104 may also be referred to as a station, a mobile station, a subscriber station, a mobile unit, a subscriber unit, a wireless unit, a remote unit, a mobile device, a wireless device, a wireless communication device, a remote device, a mobile subscriber station, an access terminal, a mobile terminal, a wireless terminal, a remote terminal, a cell phone, a user agent, a mobile client, a client, or some other suitable term.

[0058] Refer again to Figure 1, in some aspects, the UE 104 may include a sidelink C-DRX enhancement component 198 configured to receive a sidelink DRX configuration from a transmitting UE. The C-DRX enhancement component 198 is further configured to determine whether the receiver UE is configured with a first sidelink DRX configuration or a second sidelink DRX configuration, where the first sidelink DRX configuration configures the receiver UE to transition to a sleep state when a sidelink WUS is indicated, and the second sidelink DRX configuration configures the receiver UE to transition to an awake state when a sidelink WUS is indicated. In other aspects, the sidelink C-DRX enhancement component 198 is configured to determine whether a sidelink WUS is received within a sidelink WUS monitoring occasion in a first DRX cycle based on the sidelink DRX configuration. The sidelink C-DRX enhancement component 198 is further configured to transition to a sleep state in a second DRX cycle based on receiving the sidelink WUS within the sidelink WUS monitoring occasion and the sidelink DRX configuration configuring the receiver UE with the first sidelink DRX configuration. The sidelink C-DRX enhancement component 198 is further configured to transition to an awake state in a second DRX cycle based on receiving the sidelink WUS within the sidelink WUS monitoring occasion and the sidelink DRX configuration configuring the receiver UE with the second sidelink DRX configuration.

[0059] In some aspects, another UE 104 may include a sidelink C-DRX enhancement configuration component 199 configured to determine a first sidelink DRX configuration to configure the receiver UE to transition to a sleep state when a sidelink WUS is indicated. The sidelink C-DRX enhancement configuration component 199 is further configured to determine a second sidelink DRX configuration to configure the receiver UE to transition to an awake state when a sidelink WUS is indicated. In other aspects, the sidelink C-DRX enhancement configuration component 199 is configured to send the sidelink DRX configuration to the receiver UE via a transceiver to configure the receiving UE with the first sidelink DRX configuration or the second sidelink DRX configuration. The sidelink C-DRX enhancement configuration component 199 is further configured to send the sidelink WUS to the receiver UE via the transceiver within the sidelink WUS monitoring occasion in a first DRX cycle based on the sidelink DRX configuration. Further related aspects and features are described in more detail. Although the following description may focus on 5G NR, the concepts described herein may be applicable to other similar areas, such as LTE, LTE-A, CDMA, GSM, and other wireless technologies. Figures 5 to 18 Further related aspects and features are described in more detail. Although the following description may focus on 5G NR, the concepts described herein may be applicable to other similar areas, such as LTE, LTE-A, CDMA, GSM, and other wireless technologies.

[0060] Figure 2A is a diagram 200 illustrating an example of a first subframe within a 5G / NR frame structure. Figure 2B is a diagram 230 illustrating an example of a DL channel within a 5G / NR subframe. Figure 2CFIG. 250 is an illustration example of a second subframe within a 5G / NR frame structure. Figure 2D FIG. 280 is an illustration example of an UL channel within a 5G / NR subframe. The 5G / NR frame structure can be FDD, where for a particular set of subcarriers (carrier system bandwidth), the subframes within that set of subcarriers are dedicated to DL or UL, or can be TDD, where for a particular set of subcarriers (carrier system bandwidth), the subframes in the set of subcarriers are dedicated to both DL and UL. In Figure 2A 、 Figure 2C the example provided, it is assumed that the 5G / NR frame structure is TDD, where subframe 4 is configured with slot format 28 (mostly DL), where D is DL, U is UL, and X is flexibly used between DL / UL, and subframe 3 is configured with slot format 34 (mostly UL). Although subframes 3 and 4 are shown as having slot formats 34 and 28 respectively, any particular subframe can be configured with any of the various available slot formats 0 - 61. Slot formats 0 and 1 are full DL and full UL respectively. The other slot formats 2 - 61 include a mixture of DL, UL, and flexible symbols. The UE is configured with the slot format by receiving a slot format indicator (SFI) (configured dynamically via DL control information (DCI) or semi-statically / statically via radio resource control (RRC) signaling). Note that the following description also applies to a 5G / NR frame structure that is TDD.

[0061] Other wireless communication technologies may have different frame structures and / or different channels. One frame (10 ms) can be divided into 10 equal-sized subframes (1 ms). Each subframe may include one or more slots. A subframe may also include mini-slots, which may include 7, 4, or 2 symbols. Each slot may include 7 or 14 symbols, depending on the slot configuration. For slot configuration 0, each slot may include 14 symbols, and for slot configuration 1, each slot may include 7 symbols. The symbols on the DL can be cyclic prefix (CP) OFDM (CP - OFDM) symbols. The symbols on the UL can be CP - OFDM symbols (for high throughput scenarios) or discrete Fourier transform (DFT) spread OFDM (DFT - s - OFDM) symbols (also known as single carrier frequency division multiple access (SC - FDMA) symbols) (for power - limited scenarios; limited to single - stream transmission). The number of slots within a subframe is based on the slot configuration and numerology. For slot configuration 0, the different numerologies μ0 to 5 allow each subframe to have 1, 2, 4, 8, 16, and 32 slots respectively. For slot configuration 1, the different numerologies 0 to 2 allow each subframe to have 2, 4, and 8 slots respectively. Thus, for slot configuration 0 and numerology μ, there are 14 symbols per slot and 2 μtime slots. The subcarrier spacing and symbol length / duration are functions of the parameter set. The subcarrier spacing can be equal to 2 μ *15 kHz, where μ ranges from parameter set 0 to 5. Thus, the subcarrier spacing for parameter set μ = 0 is 15 kHz, and the subcarrier spacing for parameter set μ = 5 is 480 kHz. The symbol length / duration is negatively correlated with the subcarrier spacing. Figures 2A to 2D An example of slot configuration 0 with 14 symbols per time slot and parameter set μ = 0 with 1 time slot per subframe is provided. The subcarrier spacing is 15 kHz and the symbol duration is approximately 66.7 μs.

[0062] A resource grid can be used to represent the frame structure. Each time slot includes a resource block (RB) (also referred to as a physical RB (PRB)) that extends over 12 consecutive subcarriers. The resource grid is divided into multiple resource elements (REs). The number of bits carried by each RE depends on the modulation scheme.

[0063] As Figure 2A illustrated, some of the REs carry reference (pilot) signals (RS) for the UE. The RS can include demodulation RS (DM-RS) for channel estimation at the UE (indicated as R x , where 100x is the port number, but other DM-RS configurations are possible) and channel state information reference signal (CSI-RS). The RS can also include beam measurement RS (BRS), beam refinement RS (BRRS), and phase tracking RS (PT-RS).

[0064] Figure 2B Examples of various DL channels within a subframe of a frame are illustrated. The physical downlink control channel (PDCCH) carries DCI within one or more control channel elements (CCEs), each CCE including nine resource element groups (REGs), each REG including four consecutive REs in an OFDM symbol. The primary synchronization signal (PSS) can be in symbol 2 of a specific subframe of the frame. The PSS is used by the UE 104 to determine subframe / symbol timing and the physical layer identity. The secondary synchronization signal (SSS) can be in symbol 4 of a specific subframe of the frame. The SSS is used by the UE to determine the physical layer cell identity group number and radio frame timing. Based on the physical layer identity and the physical layer cell identity group number, the UE can determine the physical cell identifier (PCI). Based on the PCI, the UE can determine the location of the aforementioned DM-RS. The physical broadcast channel (PBCH) carrying the master information block (MIB) can be logically grouped with the PSS and SSS to form a synchronization signal (SS) / PBCH block. The MIB provides the system frame number (SFN) and the number of RBs in the system bandwidth. The physical downlink shared channel (PDSCH) carries user data, broadcast system information not transmitted via the PBCH (such as system information blocks (SIBs)), and paging messages.

[0065] As Figure 2C illustrated, some of the REs in the RE carry DM-RS (designated as R for a particular configuration, but other DM-RS configurations are possible) for channel estimation at the base station. The UE may transmit DM-RS for the physical uplink control channel (PUCCH) and the physical uplink shared channel (PUSCH). The PUSCH DM-RS may be transmitted in the previous one or two symbols of the PUSCH. Depending on whether a short PUCCH or a long PUCCH is transmitted and depending on the particular PUCCH format used, the PUCCH DM-RS may be transmitted in different configurations. Although not shown, the UE may transmit a sounding reference signal (SRS). The SRS may be used by the base station for channel quality estimation to enable frequency-dependent scheduling of the UL.

[0066] Figure 2D Examples of various UL channels within a subframe of a frame are illustrated. The PUCCH may be located at the position indicated in one configuration. The PUCCH carries uplink control information (UCI), such as a scheduling request, a channel quality indicator (CQI), a precoding matrix indicator (PMI), a rank indicator (RI), and HARQ ACK / NACK feedback. The PUSCH carries data and may additionally be used to carry a buffer status report (BSR), a power headroom report (PHR), and / or UCI.

[0067] Figure 3 Example FIG. 300 is shown, which shows a non-limiting example of time and frequency resources that may be used for sidelink-based wireless communication. In some examples, the time and frequency resources may be based on a time slot structure. In other examples, a different structure may be used. In some examples, the time slot structure may be within the 5G / NR frame structure. Although the following description may focus on 5G NR, the concepts described herein may be applicable to other similar domains, such as LTE, LTE-A, CDMA, GSM, and other wireless technologies. This is merely an example, and other wireless communication technologies may have different frame structures and / or different channels. A frame (10 ms) may be divided into 10 equally sized subframes (1 ms). Each subframe may include one or more time slots. The subframe may also include mini-slots, which may include 7, 4, or 2 symbols. Each time slot may include 7 or 14 symbols, depending on the time slot configuration. For time slot configuration 0, each time slot may include 14 symbols, and for time slot configuration 1, each time slot may include 7 symbols. FIG. 300 illustrates single time slot transmission, for example, which may correspond to a 0.5 ms transmission time interval (TTI).

[0068] The resource grid can be used to represent the frame structure. Each time slot may include a resource block (RB) (also referred to as a physical RB (PRB)) that extends over 12 consecutive subcarriers. The resource grid is divided into a plurality of resource elements (REs). The number of bits carried by each RE depends on the modulation scheme. Figure 300 also shows a plurality of subchannels, where each subchannel may include a plurality of RBs. For example, one subchannel in sidelink communication may include 10 - 100 RBs. As Figure 3 shown, the first symbol of the subframe may be a symbol for automatic gain control (AGC). Some REs may include control information, for example, together with the PSCCH and / or PSSCH. The control information may include sidelink control information (SCI). For example, the PSCCH may include the SCI of the first stage. The PSCCH resources may start from the first symbol of the time slot and may occupy 1, 2, or 3 symbols. The PSCCH may occupy at most one subchannel with the lowest subcarrier index. Figure 3 Symbols that may include the PSSCH are also shown. Figure 3 The symbols indicated for the PSCCH or PSSCH in include PSCCH or PSSCH REs. Such symbols corresponding to the PSSCH may also include REs containing the second stage SCI and / or data. At least one symbol may be used for feedback (e.g., PSFCH), as described herein. As Figure 3 shown, symbols 12 and 13 are indicated for the PSFCH, which indicates that these symbols include PSFCH REs. In some aspects, symbol 12 of the PSFCH may be a repetition of symbol 13. Gap symbols before and / or after the feedback may be used for the turnaround between receiving data and sending feedback. As Figure 3 shown, symbol 10 includes a gap symbol to enable the turnaround for the feedback in symbol 11. Another symbol (e.g., at the end of the time slot) (symbol 14) may be used as a gap. This gap enables the device to switch from operating as a transmitting device to preparing to operate as a receiving device, for example, in a subsequent time slot. As illustrated, data may be transmitted in the remaining REs. The data may include the data messages described herein. The position of any one of the PSCCH, PSSCH, PSFCH, and gap symbols may be different from Figure 3 the example shown.

[0069] Figure 4It is a block diagram of the communication between the base station 410 in the access network and the UE 450. In the DL, IP packets from the EPC 160 can be provided to the controller / processor 475. The controller / processor 475 implements layer 3 and layer 2 functionality. Layer 4 includes the radio resource control (RRC) layer, and layer 2 includes the service data adaptation protocol (SDAP) layer, the packet data convergence protocol (PDCP) layer, the radio link control (RLC) layer, and the media access control (MAC) layer. The controller / processor 475 provides RRC layer functionality associated with the broadcast of system information (e.g., MIB, SIB), RRC connection control (e.g., RRC connection paging, RRC connection establishment, RRC connection modification, and RRC connection release), inter-radio access technology (RAT) mobility, and measurement configuration for UE measurement reporting; PDCP layer functionality associated with header compression / decompression, security (encryption, decryption, integrity protection, integrity verification), and handover support functions; RLC layer functionality associated with the transfer of upper layer packet data units (PDUs), error correction via ARQ, concatenation, segmentation, and reassembly of RLC service data units (SDUs), re-segmentation of RLC data PDUs, and re-ordering of RLC data PDUs; and MAC layer functionality associated with the mapping between logical channels and transport channels, multiplexing of MAC SDUs onto transport blocks (TBs), demultiplexing of MAC SDUs from TBs, scheduling information reporting, error correction via HARQ, priority handling, and logical channel prioritization.

[0070] The transmit (TX) processor 416 and the receive (RX) processor 470 implement layer 1 functionality associated with various signal processing functions. Layer 1, which includes the physical (PHY) layer, may include error detection on the transport channel, forward error correction (FEC) encoding / decoding of the transport channel, interleaving, rate matching, mapping to the physical channel, modulation / demodulation of the physical channel, and MIMO antenna processing. The TX processor 416 handles the mapping to signal constellations based on various modulation schemes (e.g., binary phase shift keying (BPSK), quadrature phase shift keying (QPSK), M-phase phase shift keying (M-PSK), M-quadrature amplitude modulation (M-QAM)). The encoded and modulated symbols may then be split into parallel streams. Subsequently, each stream may be mapped to OFDM subcarriers, multiplexed with reference signals (e.g., pilots) in the time domain and / or frequency domain, and then combined together using an inverse fast Fourier transform (IFFT) to generate a physical channel carrying a time-domain OFDM symbol stream. The OFDM stream is precoded in space to generate multiple spatial streams. Channel estimates from the channel estimator 474 may be used to determine the encoding and modulation schemes, as well as for spatial processing. The channel estimates may be derived from reference signals transmitted by the UE 450 and / or channel state feedback. Then, each spatial stream may be provided to a different antenna 420 via a separate transmitter 418TX. Each transmitter 418TX modulates an RF carrier with the corresponding spatial stream for transmission.

[0071] At the UE 450, each receiver 454RX receives signals via its corresponding antenna 452. Each receiver 454RX recovers the information modulated onto the RF carrier and provides the information to the receive (RX) processor 456. The TX processor 468 and the RX processor 456 implement layer 1 functionality associated with various signal processing functions. The RX processor 456 may perform spatial processing on the information to recover any spatial streams destined for the UE 450. If multiple spatial streams are destined for the UE 450, they may be combined by the RX processor 456 into a single OFDM symbol stream. The RX processor 456 then uses a fast Fourier transform (FFT) to transform the OFDM symbol stream from the time domain to the frequency domain. The frequency-domain signal includes a separate OFDM symbol stream for each subcarrier of the OFDM signal. The symbols and reference signals on each subcarrier are recovered and demodulated by determining the most likely signal constellation points transmitted by the base station 410. These soft decisions may be based on channel estimates computed by the channel estimator 458. The soft decisions are then decoded and deinterleaved to recover the data and control signals originally transmitted by the base station 410 on the physical channel. The data and control signals are then provided to the controller / processor 459, which implements layer 4 and layer 2 functionality.

[0072] The controller / processor 459 may be associated with a memory 460 that stores program code and data. The memory 460 may be referred to as a computer-readable medium. In the UL, the controller / processor 459 provides demultiplexing between the transport channel and the logical channel, packet reassembly, decryption, header decompression, and control signal processing for IP packets recovered from the EPC 160. The controller / processor 459 is also responsible for error detection using the ACK and / or NACK protocols to support HARQ operations.

[0073] Similar to the functionality described in connection with DL transmissions performed by the base station 410, the controller / processor 459 provides RRC layer functionality associated with system information (e.g., MIB, SIB) acquisition, RRC connection, and measurement reporting; PDCP layer functionality associated with header compression / decompression and security (encryption, decryption, integrity protection, integrity verification); RLC layer functionality associated with the transfer of upper layer PDUs, error correction via ARQ, concatenation, segmentation, and reassembly of RLC SDUs, re-segmentation of RLC data PDUs, and re-ordering of RLC data PDUs; and MAC layer functionality associated with the mapping between the logical channel and the transport channel, multiplexing of MAC SDUs onto TBs, demultiplexing of MAC SDUs from TBs, scheduling information reporting, error correction via HARQ, priority handling, and logical channel prioritization.

[0074] Channel estimates derived by the channel estimator 458 based on reference signals or feedback transmitted by the base station 410 may be used by the TX processor 468 to select an appropriate decoding and modulation scheme and to facilitate spatial processing. The spatial streams generated by the TX processor 468 may be provided to different antennas 452 via a separate transmitter 454TX. Each transmitter 454TX modulates an RF carrier with the corresponding spatial stream for transmission.

[0075] UL transmissions are processed at the base station 410 in a manner similar to that described in connection with the receiver functionality at the UE 450. Each receiver 418RX receives signals via its corresponding antenna 420. Each receiver 418RX recovers the information modulated onto the RF carrier and provides the information to the RX processor 470.

[0076] The controller / processor 475 may be associated with a memory 476 that stores program code and data. The memory 476 may be referred to as a computer-readable medium. In the UL, the controller / processor 475 provides demultiplexing between the transport channel and the logical channel, packet reassembly, decryption, header decompression, control signal processing for IP packets recovered from the UE 450. The IP packets from the controller / processor 475 may be provided to the EPC 160. The controller / processor 475 is also responsible for error detection using the ACK and / or NACK protocols to support HARQ operations.

[0077] At least one of TX processor 468, RX processor 456, and controller / processor 459 may be configured to perform aspects related to Figure 1 the sidelink C-DRX enhancement component 198.

[0078] At least one of TX processor 416, RX processor 470, and controller / processor 475 may be configured to perform aspects related to Figure 1 the sidelink C-DRX enhancement configuration component 199.

[0079] The UE may be configured by the base station for DRX mode at the Uu interface. When there is no data to be transmitted in either direction between the UE and the base station, e.g., no uplink or downlink transmission at the Uu interface, the UE may enter the DRX mode, where the UE may use a sleep and wake cycle to discontinuously monitor the control channel. DRX saves battery power at the UE to improve power efficiency. In the absence of DRX, the UE may monitor the control channel in each time slot / subframe to check for data for the UE. Continuous monitoring of the control channel places a demand on the UE's battery power. The sidelink DRX configuration may be configured by the network in RRC signaling from the base station (e.g., in an RRC connection setup request or an RRC connection reconfiguration request) for the PC5 interface. The sidelink DRX configuration may include the configuration of any one of a plurality of timers and values, e.g., a sidelink on-duration timer, a sidelink DRX inactivity timer, a sidelink DRX HARQ retransmission timer, a value of the sidelink DRX start offset, and / or a sidelink DRX cycle, etc. The sidelink DRX cycle may include a sidelink DRX active duration. The sidelink DRX active duration may refer to the duration during which the UE operating as a transmitter is active or the UE operating as a receiver is active. The sidelink DRX cycle may also include the periodic repetition of a sidelink on-duration during which the UE monitors the PSCCH (e.g., SCI-1 and / or SCI-2) and a off-duration, which may be referred to as a DRX opportunity. During the off-duration, the UE does not monitor the PSCCH for scheduling on the sidelink. The UE may enter a sleep mode or a low-power mode, in which the UE minimizes power consumption by turning off the radio frequency (RF) function and not detecting communication from the base station.

[0080] As an example of DRX at the Uu interface, the DRX inactivity timer may indicate the time (e.g., expressed in terms of the TTI duration) after the UE has successfully decoded a PDCCH when the UE may enter the off duration again. The on duration timer may indicate the amount of time the UE monitors communication from the base station when the UE wakes up from the off duration in the DRX cycle. For example, the on duration timer may give the number of consecutive PDCCH subframes monitored / decoded when the UE wakes up from the off duration in the DRX cycle. If at least one associated timer is running (e.g., the DRX on duration timer, the DRX inactivity timer, and / or the DRX retransmission timer) and the UE is monitoring communication from the base station, the UE may be considered to be in DRX active time.

[0081] In an example of sidelink DRX at the PC5 interface, the sidelink DRX inactivity timer may indicate the time (e.g., expressed in terms of the slot or subframe duration) from when the UE has successfully decoded a PSCCH until the UE may enter the off duration again. The sidelink on duration timer may indicate the amount of time the UE monitors communication from other UEs at the sidelink or at the PC5 interface when the UE wakes up from the off duration in the DRX cycle. For example, the on duration timer may give the number of consecutive subframes or slots (e.g., physical slots or logical slots, where a logical slot is a slot available for sidelink communication with data) monitored / decoded when the UE wakes up from the off duration in the DRX cycle. If at least one associated timer is running (e.g., the DRX on duration timer, the DRX inactivity timer, and / or the DRX retransmission timer or the HARQ retransmission timer) and the UE is monitoring communication on the sidelink (i.e., the PC5 interface), the UE may be considered to be in DRX active time.

[0082] The connected mode DRX (C-DRX) mechanism is introduced to reduce power consumption by allowing the UE to periodically enter a power saving mode (or sleep state), where the UE may turn off the main circuits when no packets are expected to arrive. However, the UE also wakes up periodically to monitor for any packet arrivals. To prevent any data loss, the UE and the network may need to have a predefined agreement regarding the periodic transitions of the UE between the sleep state and the wake state. Typically, the UE receives the DRX configuration parameters in a downlink RRC configuration message transmitted by the network.

[0083] A wake-up signal (WUS) is introduced to further reduce the power consumption of the UE, where the WUS is a special downlink control signal (e.g., Physical Downlink Control Channel (PDCCH)) transmitted by the network before the DRX active duration to indicate whether the UE should remain active to receive new data or skip the current DRX active duration until the next DRX active duration. The WUS can be transmitted outside the DRX active duration by using group common downlink control information (DCI) with a cyclic redundancy check (CRC) scrambled by a Radio Network Temporary Identifier (RNTI) (referred to as Power Saving RNTI (PS-RNTI)). The DCI can have a specified format (e.g., DCI format 2_6) that can carry one or more information blocks, where each information block is intended for a specific UE (e.g., block number 1, block number 2,......, block number N).

[0084] In the Uu link power saving technology, a configurable offset is configured before the DRX active duration cycle for the PDCCH-based WUS to achieve improvements in power saving. A C-DRX mechanism is also introduced in sidelink communication to save power. It may be desirable to improve power efficiency during C-DRX operation while reducing the likelihood of unnecessary wake-up events in sidelink communication.

[0085] The present subject technology provides for facilitating C-DRX enhancements by using WUS for sidelink communication. In some specific implementations, a receiver UE for using WUS to facilitate C-DRX enhancements can receive a sidelink DRX configuration and determine whether the sidelink DRX configuration configures the receiver UE with a first sidelink DRX configuration or a second sidelink DRX configuration, where the first sidelink DRX configuration configures the receiver UE to transition to a sleep state when a sidelink WUS is indicated, and the second sidelink DRX configuration configures the receiver UE to transition to a wake-up state when a sidelink WUS is indicated. The UE can determine whether to receive a sidelink WUS within a sidelink WUS monitoring occasion in a first DRX cycle based on the sidelink DRX configuration. The UE can also transition to a sleep state in a second DRX cycle based on receiving the sidelink WUS within the sidelink WUS monitoring occasion and the sidelink DRX configuration configuring the receiver UE with the first sidelink DRX configuration. The UE can also transition to a wake-up state in a second DRX cycle based on receiving the sidelink WUS within the sidelink WUS monitoring occasion and the sidelink DRX configuration configuring the receiver UE with the second sidelink DRX configuration.

[0086] In other specific embodiments, the transmitter UE may determine a first sidelink DRX configuration to configure the receiver UE to transition to a sleep state when sidelink WUS is indicated, and determine a second sidelink DRX configuration to configure the receiver UE to transition to a wake-up state when sidelink WUS is indicated. The transmitter UE may send the sidelink DRX configuration to the receiver UE via a transceiver to configure the receiving UE with the first sidelink DRX configuration or the second sidelink DRX configuration. In some specific embodiments, the transmitter UE may also send sidelink WUS to the receiver UE via the transceiver within the sidelink WUS monitoring occasion in the first DRX cycle based on the sidelink DRX configuration.

[0087] Figure 5 Example 500 of sidelink communication between wireless devices is illustrated. The communication may be based on a slot structure or another sidelink structure including aspects described in conjunction with Figure 3 Although the examples in Figure 5 are described for UEs 502, 504, 506, 508, the aspects may be applied to other wireless devices configured for sidelink communication, such as RSU, IAB nodes, etc.

[0088] As Figure 5 illustrated, UE 502 may send a sidelink transmission including control information (e.g., SCI) and / or a corresponding data channel (such as a Physical Sidelink Shared Channel (PSSCH)) that may be received by receiving UEs 504, 506, 508. As Figure 5As illustrated, sidelink transmissions can be sent in multicast transmissions to each of UEs 504, 506, and 508 belonging to a common group or different groups. In other respects, sidelink transmissions can be sent in broadcast transmissions to UEs 504, 506, and 508. The SCI (e.g., SCI-2) can include information for decoding the corresponding data, and the SCI (e.g., SCI-1) can also be used by the receiving device to avoid interference by suppressing transmissions on the occupied resources during data transmission. For example, the SCI (e.g., SCI-1) can reserve resources for sidelink communication. The time slots and the number of subchannels that the data transmission will occupy can be indicated in the SCI (e.g., SCI-1) from the transmitting device. In addition to operating as receiving devices, each of UEs 502, 504, 506, 508 may also be capable of operating as a transmitting device. Thus, UEs 506, 508 are illustrated as making transmissions 516 and 518. Transmissions 514, 516, or 518 can be broadcast or multicast to nearby devices. For example, UE 502 can send communications (e.g., distance-based multicast or connectionless multicast) intended to be received by other UEs within the desired communication range 501 of UE 502. In other examples, transmissions 514, 516, or 518 can be multicast to nearby devices that are group members (e.g., connection-based multicast). In other examples, transmissions 514, 516, or 518 can be unicast from one UE to another UE. In some respects, UE 502 can be the group leader for connection-based multicast. In other respects, UE 502 can be the cluster head for distance-based multicast or connectionless multicast. In other respects, UE 502 can be a scheduling UE for managing and / or supporting sidelink communication between nearby UEs (e.g., UEs 504, 506, or 508). Additionally or alternatively, RSU 507 can receive communications from and / or send communications to UE 508.

[0089] UEs 502, 504, 506, 508, and / or RSU 507 can include sidelink C-DRX enhancement components similar to the sidelink C-DRX enhancement component 198 described in connection with Figure 1 Additional or alternative, UEs 502, 504, 506, 508, and / or RSU 507 can include sidelink C-DRX enhancement configuration components similar to the sidelink C-DRX enhancement configuration component 199 described in connection with Figure 1 description.

[0090] Resource allocation refers to how resources are allocated to devices for packet transmission. In sidelink communication, resource allocation can be performed in a centralized manner (mode 1) or a distributed manner (mode 2). When operating in mode 1, the resource allocation for sidelink communication is determined by the base station. For example, the base station can send an indication to the UE, indicating the resources allocated to the UE for sidelink communication (e.g., sending sidelink data packets to other UEs). When operating in mode 2, the resource allocation for sidelink communication is determined by the communicating UEs. For example, the transmitting UE can autonomously determine the resource allocation for sending sidelink control and data to one or more receiving UEs. When operating in mode 2 (e.g., in a distributed manner), the transmitting UE can determine the resources for communication from a resource pool. A resource pool refers to a set of time and / or frequency resources on which sidelink communication can occur.

[0091] As Figure 5 shown, a transmitter (Tx) UE 502 and a receiver (Rx) UE 504 can communicate with each other via a sidelink. In some sidelink modes, the base station 102 / 180 can communicate with the Tx UE 502 via a first access link (not shown). Additionally or alternatively, in some sidelink modes, the base station 102 / 180 can communicate with the Rx UE 504 via a second access link (not shown). The Tx UE 502 and / or the Rx UE 504 can correspond to one or more UEs described elsewhere herein, such as Figure 1 UE104. Thus, the direct link between UEs 104 (e.g., via the PC5 interface) can be referred to as a sidelink, and the direct link between the base station 102 / 180 and the UE 104 (e.g., via the Uu interface) can be referred to as an access link. Sidelink communication can be sent via the sidelink, and access link communication can be sent via the access link. Access link communication can be downlink communication (from the base station 102 / 180 to the UE 104) or uplink communication (from the UE 104 to the base station 102 / 180).

[0092] As described above, the UE 502 may operate in Mode 1, where resource selection and / or scheduling is performed by the base station 102 / 180. That is, in Mode 1, the base station 102 / 180 allocates resources for transmitting sidelink communication. Specifically, the base station 102 / 180 may send downlink control information (DCI) (e.g., in DCI format 3_0), indicating resource allocation (e.g., time resources and / or frequency resources) and / or transmission timing. In Mode 1, the MCS value for sidelink transmission may be selected by the UE 502 (e.g., within the limits set by the base station 102 / 180). Additionally, Mode 1 may support dynamic grant or configured grant for scheduling sidelink transmission. The configured grant may be of type 1 (e.g., which may be activated by the base station 102 / 180 via radio resource control (RRC) signaling) or type 2 (e.g., which may be activated by the base station 102 / 180 via DCI signaling).

[0093] As described above, the UE 502 may operate in Mode 2, where resource selection and / or scheduling is performed by the UE 502. That is, the transmitting UE 502 may autonomously determine the resources for sidelink transmission. In this case, the transmitting UE 502 may perform channel sensing by performing blind decoding of all PSCCH channels to determine the resources reserved for sidelink transmission (e.g., by other transmitting UEs). In this way, the transmitting UE 502 may determine the available resources and may report the available resources to the upper layer of the transmitting UE 502 that determines the resource usage. The receiving UE 504 operates according to the same behavior in Mode 1 or Mode 2. In some aspects, the UE 502 may perform resource selection and / or scheduling by sensing the channel availability for transmission. For example, the UE 502 may measure the received signal strength indication (RSSI) parameter associated with various sidelink channels (e.g., the sidelink RSSI (S-RSSI) parameter), may measure the reference signal received power (RSRP) parameter associated with various sidelink channels (e.g., the PSCCH-RSRP or PSSCH-RSRP parameter), may measure the reference signal received quality (RSRQ) parameter associated with various sidelink channels (e.g., the PSSCH-RSRQ parameter), etc., and may select the channel for sidelink communication transmission at least partially based on these measurement results.

[0094] In some cases, the UE 502 can communicate directly with another UE 504 on the sidelink (or with another group of UEs 506, 508; RSU 507) (e.g., using the peer-to-peer (P2P) or D2D protocol). Such communication can be referred to as D2D or sidelink communication, where the first UE 502 can be scheduled (e.g., by the base station 102 / 180 or another UE 104) to send data or control information to the second UE 504 on the sidelink. In some cases, the sidelink can be a communication link or signal sent between different UEs 104 in the network, where one UE 104 can act as a relay for information sent by another device.

[0095] In the example of the wireless communication system 500, in addition to direct communication with the base station 102 within the coverage area 501 of the base station 102, one or more UEs in a group of UEs 104 (e.g., UE 502 and UE 504) can also support sidelink communication. In such cases, the UEs 502 and 504 can be within the coverage. For example, the UE 502 can communicate with the base station 102 via the communication link 120 while maintaining sidelink communication with the UE 504 on the sidelink 230-a. Additionally, the UE 504 can communicate with the base station on the communication link 120 while communicating with the UE 502 using the sidelink channel. In some coverage cases, each UE 104 can be connected to the base station 102 via a direct link (e.g., via the Uu interface).

[0096] In the example of the wireless communication system 500, one or more UEs in a group of UEs 104 (e.g., UE 508; RSU 507) can support sidelink communication technologies. In Figure 5 the example, each of the RSU 507 and the UE 508 can be outside the coverage area 501 and can communicate with the base station 102 using a non-direct link (e.g., the RSU 507, UE 508 may not have a Uu or RRC connection established with the base station 102). In other cases, the RSU 507 can be within the coverage area 501 but may not be able to communicate directly with the base station 102 (e.g., the RSU 507 may experience interference, reduced signal strength, or otherwise blocked communication). In these cases, the RSU 507 can use the sidelink channel to communicate with the UE 508.

[0097] In Figure 5In the example, the group of UEs 104 may be in partial coverage (e.g., at least one of the UEs may communicate directly with the base station, and at least one other UE may be outside the coverage). In such a partial coverage scenario, the UE 104 that communicates directly with the base station (e.g., UE 504) may act as a relay for the information sent from the base station 102. For example, UE 504 may receive data or control information directly from the base station 102 via the communication link 120, and may relay this information to UE 506 via the sidelink channel. In such a case, UE 504 may assist in the communication between the base station 102 and the UE 506 outside the coverage.

[0098] Radio resource allocation for sidelink communication may be based on resource reservation (e.g., mode 2). For example, when a UE is about to send data on the sidelink, the UE may first determine whether the resources are reserved by other UEs. Then, the UE may reserve resources from the remaining available unreserved resources. The resource allocation for each UE may be in units of one or more subchannels (e.g., subchannels SC1 to SC5) in the frequency domain, and may be based on one time slot in the time domain. The UE may also use the resources in the current time slot to perform the first transmission, and may reserve resources in future time slots for retransmission.

[0099] Figure 6 Example DRX timelines 600, 650 are illustrated. In DRX timeline 600, UE 604a may be configured for DRX by the base station (e.g., 102 / 180). During the RRC connected state, when there is no data transmission in either direction (e.g., UL / DL), UE 604a may operate in the DRX mode. In the DRX mode, UE 604a uses "sleep" and "wake-up" cycles to discontinuously monitor the PDCCH channel. When UE 604a is in the RRC connected state or RRC connected mode, DRX may also be referred to as connected mode DRX (C-DRX). DRX saves battery power at UE 604a. In the non-DRX mode, UE 604a monitors the PDCCH in each subframe to check for available downlink data. Continuous monitoring of the PDCCH consumes the battery power of UE 604a.

[0100] The DRX configuration of UE 604a can be configured by the network using RRC signaling from base station 102 / 180 (such as in an RRC connection setup request or an RRC connection reconfiguration request). The DRX configuration can include the configuration of one or more timers and values. In some examples, the DRX configuration can include any one of an on-duration timer, a DRX inactivity timer, a DRX retransmission timer, a DRX UL retransmission timer, a DRX long cycle 690, a value of a DRX start offset, a DRX short cycle timer 682, and / or a DRX short cycle 680, etc. As illustrated by DRX timeline 600, DRX cycle 610 can include the periodic repetition of an on-duration and an off-duration 630 during which UE 604a monitors the PDCCH from base station 102 / 180.

[0101] DRX cycle 610 can include an on-duration 620 during which the UE monitors the PDCCH periodically and an off-duration 630 during which the UE does not monitor the PDCCH. The off-duration 630 can be referred to as a DRX opportunity. During the off-duration 630, UE 604a does not monitor the PDCCH. UE 604a can enter a sleep mode or a low-power mode, in which UE 604a reduces power consumption by turning off the RF function and not detecting communications from another device (e.g., base station 102 / 180 at the Uu interface or sidelink UE 104 at the PC5 interface).

[0102] The on-duration timer can correspond to the number of consecutive PDCCH subframes to be monitored or decoded when UE 604a wakes up from the off-duration 630 in DRX cycle 610. The DRX retransmission timer can correspond to the number of consecutive PDCCH subframes for UE 604a to monitor when UE 604a expects a retransmission. The DRX inactivity timer can correspond to the amount of time before UE 604a can enter the off-duration 630 again after successfully decoding the PDCCH. This amount of time can be expressed in terms of the TTI duration. After UE 604a successfully receives downlink data, the DRX inactivity timer can start counting the number of subframes. If any uplink or downlink data transmission occurs while the DRX inactivity timer is running, the timer restarts. If the DRX inactivity timer expires without uplink or downlink activity, UE 604a can enter DRX cycle 610 to achieve power savings.

[0103] Example DRX timeline 650 illustrates example DRX short cycle 680. For example, UE 604b may start with DRX short cycle 680. DRX short cycle 680 may correspond to the first DRX cycle that UE 604b enters after the DRX inactivity timer expires successfully. DRX short cycle 680 may include periodic on-duration 660 during which UE 604b monitors the PDCCH. UE 604b may operate using DRX short cycle 680 until DRX short cycle timer 682 expires. DRX short cycle timer 682 may correspond to a plurality of consecutive subframes during which UE 604b follows short DRX cycle 680 after the DRX inactivity timer has expired. Example DRX timeline 650 also illustrates example DRX long cycle 690. For example, once DRX short cycle 680 expires, UE 604b may enter DRX long cycle 690. DRX long cycle 690 may include periodic on-duration 670 during which UE 604b monitors the PDCCH. In some aspects, DRX short cycle 680 and DRX long cycle 690 are used together. For example, multiple DRX short cycles 680 may coexist within DRX long cycle 690. UE 604b is also capable of transitioning to the idle DRX mode based on the RRC inactivity timer.

[0104] Some NR communication systems may support much wider channel BW (CBW) that is scalable compared to LTE, which involves the data rates, latencies, bandwidths, and / or frequency bands that can be supported. The wide CBW may allow for more efficient use of resources than existing carrier aggregation (CA) schemes. Additionally, NR provides a mechanism to adjust the operating BW of a UE based on the bandwidth part (BWP) concept. When using BWP, the UE may not need to transmit or receive outside the configured frequency range of the active BWP (except for measurement gaps). The BWP concept enables improvements in power efficiency and / or reduction in power consumption, thus facilitating low-power operation.

[0105] The concept of BWP for NR may allow the UE to operate with a BW smaller than the configured CBW, which enables high-power efficiency operation. In the case of using BWP, the UE may not need to transmit or receive outside the configured frequency range of the active BWP, thereby achieving and resulting in power savings. The power savings may be attributed to certain aspects. For example, there may be power savings in some scenarios due to the possible operation at a lower sampling rate (e.g., of the UE's) RF-baseband interface and the reduced baseband processing required for transmission or reception with a narrower bandwidth. Another example is that if the carrier bandwidth before bandwidth adaptation is large, the bandwidth adaptation may provide power savings for the UE.

[0106] In 5G / NR, the BWP framework can be used to adjust the UE receiver bandwidth. The BWP framework may be a useful tool for implementing low-power operation. For example, in C-DRX wake-up, a small BWP can be used to monitor control signaling. DCI signaling can be used for BWP switching for data reception, and data scheduling can be targeted at the UE switching time delay (e.g., K0>0, where K0 is the time slot offset for determining the time slot assigned to the PDSCH scheduled by DCI). For example, DCI can provide an indication to the IoT device to switch the bandwidth part (switch to another bandwidth part) for data reception.

[0107] Figure 7 An example of sidelink communication 700 between wireless devices that enhances C-DRX using a wake-up signal for sidelink communication in accordance with one or more aspects of the present disclosure is illustrated.

[0108] In some aspects, a transmitter UE (e.g., 702) may determine a first sidelink DRX configuration to configure a receiver UE (e.g., 704) to transition to a sleep state when a sidelink WUS is indicated (represented as step "1"). For example, the first sidelink DRX configuration may configure the receiver UE 704 to transition to a sleep state when a sidelink WUS is indicated.

[0109] In other aspects, a transmitter UE (e.g., 702) may determine a second sidelink DRX configuration to configure the receiver UE 704 to transition to a wake state when a sidelink WUS is indicated (represented as step "2"). For example, the second sidelink DRX configuration configures the receiver UE 704 to transition to a wake state when a sidelink WUS is indicated.

[0110] In some aspects, the transmitter UE 702 may send a sidelink DRX configuration indicating the first sidelink DRX configuration or the second sidelink DRX configuration to one or more receiver UEs or a group of receiver UEs (e.g., 704) (represented as step "3"). The receiver UE (e.g., 704) may receive the sidelink DRX configuration.

[0111] In some aspects, the receiver UE 704 may determine whether the sidelink DRX configuration configures the receiver UE 704 with the first sidelink DRX configuration or the second sidelink DRX configuration (represented as step "4").

[0112] In some aspects, the transmitter UE 702 may send a sidelink WUS (denoted as step "5") to the receiver UE 704 within a sidelink WUS monitoring occasion in a first DRX cycle based on a sidelink DRX configuration. Subsequently, the UE 704 may determine whether to receive the sidelink WUS within the sidelink WUS monitoring occasion in the first DRX cycle based on the sidelink DRX configuration (denoted as step "6"). In some aspects, the receiver UE 704 may determine that the receiver UE 704 cannot monitor the sidelink WUS in the first DRX cycle before the next sidelink DRX on-duration in the second DRX cycle based on the receiver UE 704 being scheduled to send sidelink communication to a third UE during the sidelink WUS monitoring occasion, where the receiver UE 704 assumes that the transmitter UE 702 transmits the sidelink WUS during the sidelink WUS monitoring occasion. In this regard, the receiver 704 transitions to a wake state during the second DRX cycle and monitors sidelink data during the next sidelink DRX on-duration to avoid missing the sidelink WUS, even though it cannot monitor the sidelink WUS in an earlier WUS monitoring occasion.

[0113] In some embodiments, the sidelink WUS is associated with a fixed resource in every N subchannels, where N is a positive integer. In some aspects, the sidelink WUS is received on the fixed resource within a sidelink WUS monitoring occasion based on the sidelink WUS having a first priority that is higher than a second priority of a reservation of the fixed resource by another transmitter UE. For example, the reservation information may be transmitted by another transmitter UE via SCI-1. The transmitter UE that decides to transmit the sidelink WUS may compare the priority of the sidelink WUS with the priority of the reservation information.

[0114] In some embodiments, the receiver UE 704 may receive a sidelink WUS from the transmitter UE 702 within a first sidelink WUS monitoring occasion. In some aspects, the sidelink WUS instructs the receiver UE 704 to transition to a sleep state or a wake state for one or more sidelink DRX on-duration instances after indicating the sidelink WUS. In this regard, when the sidelink DRX on-duration corresponding to a second sidelink WUS monitoring occasion is to transition to a sleep state or a wake state, the receiver UE 704 may skip monitoring the sidelink WUS in subsequent occasions by suppressing monitoring of the second sidelink WUS monitoring occasion after the first sidelink WUS monitoring occasion.

[0115] In some specific implementations, the transmitter UE 702 and the receiver UE 704 may receive an SCI including a sidelink WUS from the transmitter UE within a sidelink WUS monitoring opportunity. In some specific implementations, the SCI includes a transmission structure containing a sidelink WUS without data. In other specific implementations, the SCI includes a transmission structure containing a sidelink WUS with data. In some aspects, the SCI includes an indication of a destination identifier to indicate which receiver UE (e.g., 704) or which group of receiver UEs is to transition to a wake state or a sleep state.

[0116] In some specific implementations, the SCI includes multiple levels, where the second level among the multiple levels carries one or more information blocks in an order based on the destination identifier of each corresponding receiver UE within a group of receiver UEs. In some aspects, each of the one or more information blocks is intended for a specific receiver UE within the group of receiver UEs. In some aspects, at least one of the one or more information blocks indicates the sidelink WUS and also indicates the number of bits corresponding to the sidelink DRX on-duration instances for a specific receiver UE to transition to a sleep state or a wake state. In some specific implementations, the bits are arranged in a bitmap, where each position of the bitmap indicates a different number of sidelink DRX on-duration instances. In other specific implementations, the bits correspond to multiple indices, where each of the multiple indices indicates a different number of sidelink DRX on-duration instances. In still other specific implementations, the bits are arranged in a start and length indicator value (SLIV) that indicates an index for starting the sidelink DRX on-duration and multiple consecutive indices corresponding to the sidelink DRX on-duration instances.

[0117] In other specific implementations, the SCI includes multiple levels, where the third level among the multiple levels carries one or more information blocks in an order based on the destination identifier of each corresponding receiver UE within a group of receiver UEs. In some aspects, each of the one or more information blocks is intended for a specific receiver UE within the group of receiver UEs. In some aspects, the second level among the multiple levels includes an indication of whether the third level among the multiple levels is being transmitted. In still other specific implementations, the SCI includes multiple levels, where the first level among the multiple levels includes an indication of the sidelink WUS.

[0118] In some specific implementations, the sidelink WUS monitoring opportunity is embedded within the sidelink DRX on-duration. In some aspects, the sidelink DRX configuration may configure a first type of sidelink DRX on-duration and a second type of sidelink DRX on-duration that is different from the first type of sidelink DRX on-duration. For example, the sidelink DRX configuration may configure a short DRX duration and a long DRX duration. In some aspects, a first sidelink DRX configuration is associated with the first type of sidelink DRX on-duration, and a second sidelink DRX configuration is associated with the second type of sidelink DRX on-duration that is different from the first type of sidelink DRX on-duration. In some specific implementations, when a sidelink WUS is received during the first type of sidelink on-duration, the receiving UE 704 transitions to the sleep state based on the first sidelink DRX configuration. In other specific implementations, when a sidelink WUS is received during the second type of sidelink on-duration, the receiving UE 704 transitions to the wake state based on the second sidelink DRX configuration. In some aspects, the sidelink DRX configuration indicates which one of the first type of sidelink DRX on-duration or the second type of sidelink DRX on-duration is configured to support micro-slot transmission. In some aspects, the receiving UE 704 may monitor the SCI during one or more micro-slots of the sidelink WUS monitoring opportunity within the first type of sidelink DRX on-duration or the second type of sidelink DRX on-duration. For example, the receiver 704 may monitor the SCI that may indicate a sidelink WUS during one or more micro-slots within the short DRX on-duration or the long DRX on-duration.

[0119] In other specific implementations, the sidelink WUS monitoring opportunity is outside the sidelink DRX on-duration within the DRX cycle. In some aspects, the sidelink DRX configuration may configure the position of the sidelink WUS monitoring opportunity by an offset between the start of the sidelink WUS monitoring window and the duration across the sidelink WUS monitoring window. In some aspects, the end of the sidelink WUS monitoring window and the start of the sidelink DRX on-duration are separated by a minimum gap based on the offset and the duration. In some aspects, the sidelink WUS monitoring window includes a plurality of candidate sidelink WUS monitoring opportunities, where the duration includes a plurality of micro-slots. In some aspects, each candidate sidelink WUS monitoring opportunity among the plurality of candidate sidelink WUS monitoring opportunities corresponds to one micro-slot among the plurality of micro-slots.

[0120] In some specific implementations, the receiver UE 704 may receive a Physical Sidelink Feedback Channel (PSFCH) including a sidelink WUS within a sidelink WUS monitoring occasion. In some specific implementations, the sidelink WUS monitoring occasion may be embedded within the sidelink DRX on duration, or in other specific implementations may be located outside the sidelink DRX on duration. In some aspects, the location of the sidelink WUS monitoring occasion is configured by a first PSFCH resource pool, which is separate from a second PSFCH resource pool for conflict indication and feedback signaling.

[0121] In some aspects, the first PSFCH resource pool and the second PSFCH resource pool include PSFCH resources having separate Physical Resource Blocks (PRBs), where different PRBs are used to allocate the sidelink WUS monitoring occasion and conflict indication and feedback signaling to the PSFCH in the same time slot. In other aspects, the first PSFCH resource pool and the second PSFCH resource pool include PSFCH resources having multiple time slots, where different numbers of PRBs are used to allocate the sidelink WUS monitoring occasion to the first PSFCH and conflict indication and feedback signaling to the second PSFCH in different time slots. In some aspects, the first PSFCH has a first periodicity greater than a second periodicity of the second PSFCH.

[0122] In other aspects, the location of the sidelink WUS monitoring occasion is configured by a PFSCH resource pool shared with feedback signaling, where different cyclic shift pairs are used to allocate the sidelink WUS monitoring occasion and feedback signaling to the same PRB.

[0123] In some specific implementations, the PSFCH includes a plurality of PRB sets divided by a plurality of sidelink DRX on-duration instances, where the order of each PRB set in the plurality of PRB sets is temporally aligned with the corresponding sidelink DRX on-duration instance. In some aspects, each PRB set in the plurality of PRB sets includes one or more PRBs mapped based on a destination identifier corresponding to the receiving UE 704 and an indication of the sidelink WUS. In some aspects, the sidelink DRX configuration indicates that the sidelink WUS monitoring occasion is located among the PSFCH occasions that are closest in position to the next sidelink DRX on-duration compared to other PSFCH occasions. In other aspects, the sidelink DRX configuration indicates that the sidelink WUS monitoring occasion is located in the first PSFCH occasion that is closest in position to the next sidelink DRX on-duration compared to the second PSFCH occasion or in the second PSFCH occasion that is second closest in position to the next sidelink DRX on-duration. In some aspects, the receiving UE 704 may monitor the PSFCH in the second PSFCH occasion and, when the PSFCH is not detected in the second PSFCH occasion, monitor the PSFCH in the first PSFCH occasion.

[0124] In some aspects, the receiving UE 704 may transition to the sleep state (denoted as step "7a") in the second DRX cycle based on receiving the sidelink WUS within the sidelink WUS monitoring occasion and the sidelink DRX configuration configuring the receiving UE 704 with the first sidelink DRX configuration. In other aspects, if the sidelink WUS is not received within the sidelink WUS monitoring occasion, the receiving UE 704 may refrain from transitioning to the sleep state during the second DRX cycle. In this regard, the receiving UE 704 may instead monitor the sidelink data during the sidelink DRX on-duration in the second DRX cycle. In some aspects, the receiving UE 704 may skip being active during the first sidelink DRX on-duration in the second DRX cycle when the receiving UE 704 transitions to the sleep state and remain in the sleep state until the second sidelink DRX on-duration in the third DRX cycle.

[0125] In other aspects, the receiving UE 704 may transition to the wake state (denoted as step "7b") in the second DRX cycle based on receiving the sidelink WUS within the sidelink WUS monitoring occasion and the sidelink DRX configuration configuring the receiving UE 704 with the second sidelink DRX configuration. In other aspects, the receiving UE 704 may refrain from transitioning to the wake state during the second DRX cycle based on not receiving the sidelink WUS within the sidelink WUS monitoring occasion.

[0126] Figure 8FIG. 800 is an illustration of an example of a DRX cycle with a WUS monitoring occasion along a timeline according to one or more aspects of the present disclosure. In some embodiments, a transmitter UE (not shown) may indicate whether a receiver UE (e.g., 804) should stay active to receive new data or skip the current sidelink DRX on-duration until the next sidelink DRX on-duration. This indication transmitted by the transmitter UE is a sidelink wake-up signal.

[0127] In some embodiments, the transmitter UE may define the interpretation of sidelink WUS via PC-5 RRC signaling. For example, the transmitter UE may send a sidelink DRX configuration. In the sidelink DRX configuration, if there is a field, then if no sidelink WUS is detected outside of the DRX active time (also referred to as the sidelink DRX on-duration), the receiver UE does not enter sleep. Alternatively, the receiver UE transitions to a sleep state (or skips the current sidelink DRX on-duration) when a sidelink WUS is indicated. For example, the receiver UE 804 may be configured with a first sidelink DRX configuration that configures the receiver UE 804 to transition to a sleep state when a sidelink WUS is detected. The receiver UE 804 may monitor for a sidelink WUS during a sidelink WUS monitoring occasion 820 and detect a sidelink WUS (e.g., 822) during the sidelink WUS monitoring occasion 820. In this regard, the receiver 804 transitions to a sleep state within the DRX cycle 810 (e.g., #n) and skips the sidelink DRX on-duration 824 within the DRX cycle 810. Within the DRX cycle 810, the receiver 804 may again monitor for a sidelink WUS during a sidelink WUS monitoring occasion 830 that is outside of the sidelink DRX on-duration 824 and the sidelink DRX on-duration 834 associated with a subsequent DRX cycle (e.g., 812). The receiver UE 804 may not detect a sidelink WUS (e.g., 832) during the sidelink WUS monitoring occasion 830, such that the receiver UE 804 stays active and inhibits transitioning to a sleep state within the DRX cycle 812. Within the DRX cycle 812, the receiver 804 may again monitor for a sidelink WUS during a sidelink WUS monitoring occasion 840 that is outside of the sidelink DRX on-duration 834 and the sidelink DRX on-duration 844 associated with a subsequent DRX cycle (e.g., 814). The receiver UE 804 may not detect a sidelink WUS (e.g., 842) during the sidelink WUS monitoring occasion 840, such that the receiver UE 804 stays active and inhibits transitioning to a sleep state within the DRX cycle 814.

[0128] Figure 9FIG. is an illustration showing another example of a DRX cycle with a WUS monitoring opportunity along timeline 900 in accordance with one or more aspects of the present disclosure. In some embodiments, a transmitter UE (not shown) may indicate whether a receiver UE (e.g., 904) should stay in a sleep state or transition to a wake state to receive new data during the next sidelink DRX on-duration. This indication transmitted by the transmitter UE is a sidelink wake-up signal.

[0129] In a sidelink DRX configuration, if a field does not exist, the receiving UE is not woken up if a sidelink WUS is not detected outside of the DRX active time. In this regard, the receiving UE will wake up only for a given DRX on-duration when a sidelink WUS is indicated. For example, the receiving UE 904 can be configured with a second sidelink DRX configuration that configures the receiving UE 904 to transition to a wake state when a sidelink WUS is detected. The receiving UE 904 can monitor for a sidelink WUS during a sidelink WUS monitoring occasion 920 and not detect a sidelink WUS during the sidelink WUS monitoring occasion 920 (e.g., 922). In this regard, the receiver 904 refrains from transitioning to a wake state within the DRX cycle 910 (e.g., #n) and skips the sidelink DRX on-duration 924 that is active within the DRX cycle 910. Within the DRX cycle 910, the receiver 904 can again monitor for a sidelink WUS during a sidelink WUS monitoring occasion 930 that is outside of the sidelink DRX on-duration 924 and a sidelink DRX on-duration 934 associated with a subsequent DRX cycle (e.g., 912). The receiving UE 904 detects a sidelink WUS during the sidelink WUS monitoring occasion 930 (e.g., 932), such that the receiving UE 904 transitions to a wake state, which in turn causes it to be active during the sidelink DRX on-duration 934 to receive new data. Within the DRX cycle 912, the receiver 904 can again monitor for a sidelink WUS during a sidelink WUS monitoring occasion 940 that is outside of the sidelink DRX on-duration 934 and a sidelink DRX on-duration 944 associated with a subsequent DRX cycle (e.g., 914). However, in this case, the receiving UE 904 cannot monitor for a sidelink WUS before the next sidelink DRX on-duration 944 because the receiving UE 904 may be transmitting to another UE during the sidelink WUS monitoring occasion 940 (represented by the dashed vertical rectangle) due to half-duplex constraints. Because the receiving UE 904 may not monitor for a sidelink WUS, the receiving UE 904 can remain active by refraining from transitioning to a sleep state within the DRX cycle 914 to receive new data during the sidelink DRX on-duration 944 because the receiving UE can assume that the transmitting UE transmitted a sidelink WUS during the sidelink WUS monitoring occasion 940.

[0130] Since a listen-before-talk (LBT) procedure is required before the transmitter UE can transmit a sidelink WUS, if the LBT procedure fails for C-DRX enhancement that utilizes WUS based on the second sidelink DRX configuration, the receiver UE may not transition to the wake state. However, for C-DRX enhancement that utilizes WUS based on the first sidelink DRX configuration, the receiver UE may transition to the wake state even if the LBT procedure fails before the transmitter UE can transmit the sidelink WUS.

[0131] Figure 10A FIG. 1000 is a diagram illustrating an example of a DRX cycle with an SCI transmitted during a WUS monitoring occasion in accordance with one or more aspects of the present disclosure. In some implementations, the sidelink WUS may be transmitted in the SCI. In some aspects, the transmission structure of the sidelink WUS may include a sidelink WUS carried in the SCI and transmitted during a sidelink WUS monitoring occasion having only an SCI structure (e.g., excluding a data payload). For example, the receiver UE 1004 may monitor the sidelink WUS during a sidelink WUS monitoring occasion 1020 that includes only an SCI structure. The receiver UE 1004 may detect the sidelink WUS during the sidelink WUS monitoring occasion 1020 within the DRX cycle 1010. Further, if the receiver UE 1004 is configured with the first sidelink DRX configuration, the receiver UE 1004 may transition to the sleep state within the DRX cycle 1012 and skip being active during the sidelink DRX on duration 1024, or if the receiver 1004 is configured with the second sidelink DRX configuration, the receiver UE 1004 may transition to the wake state within the DRX cycle 1012 and remain active during the sidelink DRX on duration 1024.

[0132] Figure 10BFIG. is another example illustration of a DRX cycle along timeline 1050 with an SCI sent in a WUS monitoring occasion that embeds a DRX ON duration instance according to one or more aspects of the present disclosure. In some specific implementations, the sidelink WUS is carried in the SCI and sent together with data. The sidelink WUS monitoring occasion may be embedded in a previous sidelink DRX ON duration. In this case, more than one DRX configuration may be configured for the receiver UE using different parameters (e.g., different ON durations, different start points, different DRX cycles). In some aspects, the configuration of the sidelink WUS sent in different DRX ON duration instances may be different. For example, there may be two types of sidelink DRX ON duration instances. For example, the first type of sidelink DRX ON duration may be referred to as a short DRX ON duration, where the sidelink WUS sent during this DRX ON duration may indicate the configuration for the receiver UE to transition to the wake state. In another example, the second type of sidelink DRX ON duration may be referred to as a long DRX ON duration, where the sidelink WUS sent during this DRX ON duration may indicate the configuration for the receiver UE to transition to the sleep state. In some aspects, if the transmitter UE fails to send the sidelink WUS during the long DRX ON duration, the transmitter UE may still use the sidelink WUS transmission in the next short DRX ON duration to control whether the receiver UE should wake up during the next long DRX ON duration.

[0133] In some aspects, the transmission structure of sidelink WUS may include sidelink WUS carried in an SCI and transmitted in a sidelink WUS monitoring occasion having the SCI and a data structure (e.g., including a data payload). In this regard, the SCI may be embedded within certain types of sidelink DRX on-duration instances (e.g., short DRX on-duration). For example, the receiver UE 1004 may monitor the sidelink WUS during a sidelink WUS monitoring occasion 1060 that is embedded within a short DRX on-duration and includes the SCI and the data structure. The receiver UE 1004 may detect the sidelink WUS during the sidelink WUS monitoring occasion 1060 within the DRX cycle 1010. Because the sidelink WUS is detected within the short DRX on-duration, the receiver UE 1004 may transition to the wake state within the DRX cycle 1012 and skip being active during the sidelink DRX on-duration 1024. Within the DRX cycle 1012, the receiver 1004 may monitor the sidelink WUS again during a sidelink WUS monitoring occasion 1064 that is embedded within a long DRX on-duration. The receiver UE 1004 may not detect the sidelink WUS (e.g., 1066) during the sidelink WUS monitoring occasion 1064. Because the sidelink WUS is not detected within the long DRX on-duration, the receiver UE 1004 inhibits transitioning to the sleep state within the DRX cycle 1012 and remains active during the long DRX on-duration (e.g., 1064). Within the DRX cycle 1012, the receiver 1004 may monitor the sidelink WUS again during a sidelink WUS monitoring occasion 1070 that is embedded within a short DRX on-duration. The receiver UE 1004 may not detect the sidelink WUS (e.g., 1072) during the sidelink WUS monitoring occasion 1070. Because the sidelink WUS is not detected within the short DRX on-duration (e.g., 1070), the receiver UE 1004 inhibits transitioning to the wake state within the DRX cycle 1014 and skips being active during the long DRX on-duration 1074 within the DRX cycle 1014. For illustrative purposes and without limiting the scope of the present disclosure, the receiver UE 1004 may transition to the sleep state within the DRX cycle 1012 before the sidelink DRX on-duration 1074.

[0134] Figure 11AFIG. is an illustration of an example of a sidelink WUS monitoring occasion that embeds a DRX-on duration according to one or more aspects of the present disclosure. In some specific implementations, a sidelink WUS may be sent at a position that embeds a previous DRX-on duration to save power. For a sidelink WUS monitoring occasion that embeds a previous DRX-on duration, the transmitter UE may indicate which type of DRX-on duration (e.g., short DRX-on duration, long DRX-on duration) is configured to perform micro-slot transmission. For example, the transmitter UE may indicate that a short DRX-on duration is performing micro-slot transmission, and thus, the receiver UE may perform micro-slot SCI monitoring. As Figure 11A illustrated, the receiver UE 1104 may monitor the sidelink WUS during multiple candidate sidelink WUS monitoring occasions embedded within a short DRX-on duration 1140. For example, the receiver UE 1104 may monitor the sidelink WUS in different micro-slots within the short DRX-on duration 1140.

[0135] Figure 11B FIG. is an illustration of an example of a sidelink WUS monitoring occasion outside of a DRX-on duration according to one or more aspects of the present disclosure. In some specific implementations, a sidelink WUS may be sent at a position outside of the sidelink DRX-on duration. For a sidelink WUS monitoring occasion outside of the sidelink DRX-on duration, the position of the sidelink WUS may be configured via PC-5 RRC with an offset parameter and a duration parameter, where the transmitter UE determines the sidelink WUS monitoring occasion for its receiver UE. In some aspects, the offset parameter may indicate a time offset between a start point of a candidate sidelink WUS monitoring occasion and a start point of the next sidelink DRX-on duration. In some aspects, the duration parameter may indicate a duration from a start point of a first candidate sidelink WUS monitoring occasion to an end point of a last candidate sidelink WUS monitoring occasion. The offset and duration parameters may be configured with a value that achieves a minimum gap between an end point of the last candidate sidelink WUS monitoring occasion and a start point of the next sidelink DRX-on duration. As Figure 11B illustrated, the receiver UE 1104 may monitor the sidelink WUS during a sidelink WUS monitoring window 1160 that includes multiple candidate sidelink WUS monitoring occasions located outside of a sidelink DRX-on duration 1162. In some specific implementations, micro-slot transmission may be used for sidelink WUS monitoring occasions outside of the sidelink DRX-on duration to provide multiple monitoring occasions within a given duration to compensate for any LBT uncertainty. For example, each occasion within the sidelink WUS monitoring window 1160 may correspond to a micro-slot.

[0136] Figure 12FIG. is an illustration of an example of a DRX cycle having a sidelink WUS associated with multiple consecutive DRX on-duration instances in accordance with one or more aspects of the present disclosure. In some embodiments, a sidelink WUS may indicate whether a receiving UE is to wake up or go to sleep during the next sidelink DRX on-duration and one or more subsequent sidelink DRX on-duration instances. If so, the receiving UE may skip a sidelink WUS monitoring occasion if the corresponding sidelink DRX on-duration has transitioned to the wake or sleep state.

[0137] As Figure 12 Illustrated, receiving UE 1204 may monitor a sidelink WUS during sidelink WUS monitoring occasion 1220 and detect the sidelink WUS (e.g., 1222) during sidelink WUS monitoring occasion 1220. In this regard, if receiving UE 1204 is configured with a first sidelink DRX configuration, receiver 1204 transitions to the sleep state within DRX cycle 1210 (e.g., #n) and skips sidelink DRX on-duration 1224 within DRX cycle 1210, or if receiving UE 1204 is configured with a second sidelink DRX configuration, receiver 1204 transitions to the wake state within DRX cycle 1210. Because the sidelink WUS 1222 detected within sidelink WUS monitoring occasion 1230 also indicates that subsequent sidelink DRX on-duration instances (e.g., 1234, 1244) are also configured with the same DRX state transition, receiving UE 1204 may skip monitoring of the sidelink WUS (e.g., 1232, 1242) during sidelink WUS monitoring occasions 1220, 1240, respectively.

[0138] In unlicensed sidelink communication, one UE may communicate with multiple UEs. To avoid overlap of sidelink WUS occasions with DRX on-duration instances of other UEs, the configuration of sidelink WUS occasions may be different for different DRX on-duration instances (e.g., the sidelink WUS monitoring occasion may be configured separately for each of the DRX on-duration instances). In some embodiments, the transmitting UE may use a destination identifier (ID) to indicate which receiving UE or group of receiving UEs needs to transition to the wake or sleep state.

[0139] In some aspects, the SCI may include the SCI-2 format, where the SCI-2 carries one or more information blocks, each information block being intended for a specific receiver UE. In some aspects, the information block may include a 1-bit sidelink WUS indication and N bits to indicate that X subsequent DRX on durations are also used for the receiver UE to transition to the wake state or the sleep state. In some aspects, the order of the information blocks may be determined by the receiver UE identifier within the group. In one example, when X = N, the N bits may be formed as a bitmap to indicate the subsequent N sidelink DRX on durations. In another example, when X = 2 N , for N = 2, index = 00 may correspond to one subsequent DRX on duration, index = 01 may correspond to two subsequent DRX on durations, and so on. In other aspects, the N bits may be formed as an SLIV to indicate the starting DRX on duration index and a plurality of consecutive indices. In some embodiments, the SCI may include a third level, where the SCI-3 carries one or more information blocks, each information block being intended for a specific receiver UE. In some aspects, if the sidelink WUS indication signal is enabled in the SCI-2, the SCI-3 may be sent by the transmitter UE. Otherwise, the transmitter UE does not send the SCI-3. In other embodiments, the sidelink WUS is carried in the SCI-1, with a 1-bit sidelink WUS indication.

[0140] To reduce the blind detection complexity, the sidelink WUS may be fixed in every N subchannels. If the subchannel to be used by the transmitter UE for the transmission of the sidelink WUS is reserved by another UE, then in some embodiments, the sidelink WUS may not be sent by the transmitter UE, or in other embodiments, the transmitter UE may compare the priority of the sidelink WUS with the priority of the reserved resource to decide whether the sidelink WUS can be sent.

[0141] Figure 13 is a diagram illustrating an example of a DRX cycle along timeline 1300 with a PSFCH transmitted during a WUS monitoring occasion according to one or more aspects of the present disclosure. In some embodiments, the sidelink WUS is carried in the PSFCH. Since the PSFCH can only carry 1-bit information, the sidelink WUS may be a 1-bit sidelink WUS indication.

[0142] In some embodiments, the position of the sidelink WUS is configured by a separate PSFCH resource pool. For example, the PSFCH may be allocated separate PRBs among resource pools. In some aspects, the sidelink WUS may be included in one PSFCH time instance. For example, PSFCH resources may be allocated for the sidelink WUS, conflict indication, and HARQ feedback in different PRBs. As Figure 13As illustrated, the receiver UE 1304 may monitor the sidelink WUS in the sidelink WUS monitoring opportunity within the PSFCH 1310. In some aspects, the PFSCH opportunity has a period N, where N is a positive integer. The PSFCH 1310 may include a first set of PRBs 1314-1 allocated for the sidelink WUS indication signal, a second set of PRBs 1314-2 allocated for the conflict indication, and a third set of PRBs 1314-3 allocated for the HARQ feedback. In some embodiments, the PSFCH opportunity that is closest in time along the timeline 1300 and prior to the next DRX on-duration (e.g., DRX on-duration 1316) may be configured to be detected by the receiver UE for transitioning between DRX states (e.g., sleep, wake). For example, the receiver UE 1304 may attempt to receive the PSFCH 1310 with the sidelink WUS indication signal in the PSFCH opportunity that is closest in time to the DRX on-duration 1316.

[0143] Figure 14 FIG. 1400 is a diagram illustrating another example of a DRX cycle with a PSFCH transmitted in a WUS monitoring opportunity in accordance with one or more aspects of the present disclosure. In some embodiments, the sidelink WUS is carried in the PSFCH. In some embodiments, the location of the sidelink WUS is configured by a separate PSFCH resource pool. In some aspects, two PSFCH time instances may be used, where one PSFCH time instance is used to exclusively transmit the sidelink WUS. For example, the PSFCH 1416-1 may include a first set of PRBs 1418-1 allocated for the conflict indication and a second set of PRBs 1418-2 allocated for the HARQ feedback. The PSFCH 1414-2 may include PRBs 1420 specifically allocated for the sidelink WUS indication signal. In some aspects, the PSFCH that includes the sidelink WUS (e.g., PSFCH 1414-2) may be transmitted in a different time slot than the PSFCH that includes the HARQ feedback and the conflict indication (e.g., PSFCH 1416-1). In this case, the PSFCH 1414-2 used to carry the indication of the sidelink WUS may have a greater periodicity than the PSFCH 1416-1. For example, each of the PSFCHs 1414-1 and 1414-2 has a period M and each of the PSFCHs 1416-1 and 1416-2 has a period N, where M is greater than N. In this case, more PRBs may be used to carry the HARQ-ACK feedback and the conflict indication to reduce the likelihood of conflicts. The number of PRBs in the resource pool for the PSFCH transmission that includes the sidelink WUS indication signal may be pre-configured or configured via RRC signaling.

[0144] In some specific implementations, the PSFCH opportunity at the position that is closest in time along the timeline 1400 and before the next DRX on-duration (e.g., DRX on-duration 1422) can be configured to be detected by the receiving UE 1404 for transitioning between DRX states (e.g., sleep, wake). For example, the receiving UE 1404 can attempt to receive the PSFCH 1414-2 with the sidelink WUS indication signal in the PSFCH opportunity that is closest in time to the DRX on-duration 1422. In other specific implementations, the PSFCH opportunity at the position that is second closest in time along the timeline 1400 and before the next DRX on-duration 1422 can be configured to be detected by the receiving UE 1404 for transitioning between DRX states. For example, the receiving UE 1404 can attempt to receive the PSFCH 1414-1 with the sidelink WUS indication signal in the PSFCH opportunity that is second closest in time to the DRX on-duration 1422. In some aspects, this configuration of the PSFCH can be done via PC-5 RRC signaling.

[0145] In some aspects, the receiving UE 1404 can first attempt to detect the sidelink WUS in the PSFCH 1414-1 at the second closest position before the DRX on-duration 1422. If the receiving UE 1404 does not detect that the PSFCH 1414-1 contains the sidelink WUS, the receiving UE 1404 can attempt to detect the sidelink WUS in the PSFCH 1414-2 at the first closest position before the DRX on-duration 1422.

[0146] In some aspects, the position of the sidelink WUS can be configured by a common PSFCH resource pool with different cyclic shift pairs. In some aspects, the PSFCH resources for the sidelink WUS can be allocated in the same PRB as the HARQ-ACK feedback. In this way, the HARQ-ACK feedback and the sidelink WUS can be configured with different cyclic shift pairs.

[0147] Figure 15 is a diagram illustrating yet another example of a DRX cycle with a PSFCH transmitted in a WUS monitoring opportunity along the timeline 1500 according to one or more aspects of the present disclosure. In some specific implementations, the PRBs in the PSFCH are divided by multiple DRX on-duration instances corresponding to one PSFCH time slot (or one PSFCH opportunity). For example, the mapping of the sidelink WUS indication signal to the PSFCH can be at least based on the destination ID corresponding to the receiving UE (e.g., 1504). This can be expressed as (destination ID) where It consists of multiple PRBs and multiple cyclic shifts corresponding to one DRX on-duration instance. In some aspects, if the transmitter UE intends to configure multiple UEs to transition to the wake state or the sleep state, the transmitter UE can simultaneously transmit multiple PSFCHs. The maximum number of PSFCHs that can be transmitted can be determined based on the UE capabilities of the receiver UE. For example, the receiver UE 1504 can monitor the sidelink WUS in the PSFCH 1514. The maximum number of PSFCHs that can be transmitted includes a first set of PRBs 1516-1 (denoted as #1) for the first DRX on-duration 1522, a second set of PRBs 1516-2 (denoted as #2) for the second DRX on-duration 1524, and a third set of PRBs 1516-3 (denoted as #3) for the third DRX on-duration 1526. In this regard, if a sidelink WUS is detected within the first set of PRBs 1516-1, the receiver UE 504 can transition the DRX state during the first DRX on-duration 1522. Similarly, if a sidelink WUS is detected within the second set of PRBs 1516-2, the receiver UE 504 can transition the DRX state during the second DRX on-duration 1524. Additionally, if a sidelink WUS is detected within the third set of PRBs 1516-3, the receiver UE 504 can transition the DRX state during the third DRX on-duration 1526.

[0148] Figure 16 FIG. 1600 is a flow chart illustrating a process of wireless communication that supports enhanced C-DRX using a wake signal for sidelink communication at a receiver UE, in accordance with some aspects of the present disclosure. As illustrated, flow chart 1600 includes several enumerated steps, but embodiments of flow chart 1600 may include additional steps before, after, and between these enumerated steps. In some embodiments, one or more of these enumerated steps may be omitted or performed in a different order. Optional aspects are represented by dashed lines.

[0149] At 1602, the UE receives a sidelink DRX configuration from a transmitter. In Figure 1 and Figures 5 to 15 context, for example, the UE 104 / 704 may receive a sidelink DRX configuration. For example, 1602 may be performed by one or more components (e.g., the controller / processor 459, the receiving processor 456, the receiver / transmitter 454, and / or the antenna 452) described with reference to Figure 4 . The sidelink DRX configuration may be received, for example, by the receiving component 1830 of the apparatus 1802 in Figure 18 via the DRX configuration component 1840.

[0150] At 1604, the UE determines whether to configure the receiving UE with the first sidelink DRX configuration or the second sidelink DRX configuration. In Figure 1 and Figures 5 to 15 context, for example, UE 104 / 704 can perform the determination between the first sidelink DRX configuration and the second sidelink DRX configuration. For example, 1604 can be performed by one or more components (such as the controller / processor 459) described with reference to Figure 4 The determination of whether to configure the receiving UE with the first sidelink DRX configuration or the second sidelink DRX configuration can be performed, for example, by the determination component 1842 through coordination with the DRX configuration component 1840 of the device 1802 in Figure 18 . If the UE 104 determines that the receiving UE is configured with the first sidelink DRX configuration, the process proceeds to block 1606; otherwise, the process proceeds to block 1608.

[0151] At 1606, the UE determines whether it receives a sidelink WUS within the sidelink WUS monitoring occasion in the first DRX cycle based on the first sidelink DRX configuration. In Figure 1 and Figures 5 to 15 context, for example, UE 104 / 704 can perform the determination of the arrival time of the sidelink WUS. For example, 1604 can be performed by one or more components (such as the controller / processor 459) described with reference to Figure 4 . The determination of whether the sidelink WUS is received within the sidelink WUS monitoring occasion can be performed, for example, by the determination component 1842 through coordination with the monitoring component 1846 of the device 1802 in Figure 18 . If the sidelink WUS is received within the sidelink WUS monitoring occasion, the process proceeds to block 1610; otherwise, the process proceeds to block 1614.

[0152] At 1608, the UE determines whether it receives a sidelink WUS within the sidelink WUS monitoring occasion in the first DRX cycle based on the second sidelink DRX configuration. In Figure 1 and Figures 5 to 15 context, for example, UE 104 / 704 can perform the determination of the arrival time of the sidelink WUS. For example, 1604 can be performed by one or more components (such as the controller / processor 459) described with reference to Figure 4 . The determination of whether the sidelink WUS is received within the sidelink WUS monitoring occasion can be performed, for example, by the determination component 1842 through coordination with the monitoring component 1846 of the device 1802 in Figure 18 . If the sidelink WUS is received within the sidelink WUS monitoring occasion, the process proceeds to block 1612; otherwise, the process proceeds to block 1616.

[0153] At 1610, the UE transitions to the sleep state in the second DRX cycle based on receiving the sidelink WUS within the sidelink WUS monitoring occasion and configuring the receiver UE with the first sidelink DRX configuration for sidelink DRX. In Figure 1 and Figures 5 to 15 context, for example, UE 104 / 704 may perform the transition to the sleep state when indicating the sidelink WUS. For example, 1604 may be performed by one or more components (such as the controller / processor 459) described with reference to Figure 4 The transition to the sleep state may be performed, for example, by the DRX state transition component 1848 in coordination with the WUS component 1844 of the apparatus 1802 in Figure 18 .

[0154] Alternatively, at 1614, the UE suppresses transitioning to the sleep state during the second DRX cycle based on not receiving the sidelink WUS within the sidelink WUS monitoring occasion and configuring the receiver UE with the first sidelink DRX configuration for sidelink DRX. In this regard, the UE may monitor sidelink data during the sidelink DRX on-duration in the second DRX cycle. In Figure 1 and Figures 5 to 15 context, for example, UE 104 / 704 may perform suppressing the transition to the sleep state after not detecting the sidelink WUS. For example, 1604 may be performed by one or more components (such as the controller / processor 459) described with reference to Figure 4 The suppression of the transition to the sleep state may be performed, for example, by the DRX state transition component 1848 in coordination with the WUS component 1844 of the apparatus 1802 in Figure 18 .

[0155] At 1612, the UE transitions to the wake state in the second DRX cycle based on receiving the sidelink WUS within the sidelink WUS monitoring occasion and configuring the receiver UE with the second sidelink DRX configuration for sidelink DRX. In Figure 1 and Figures 5 to 15 context, for example, UE 104 / 704 may perform the transition to the wake state when indicating the sidelink WUS. For example, 1604 may be performed by one or more components (such as the controller / processor 459) described with reference to Figure 4 The transition to the wake state may be performed, for example, by the DRX state transition component 1848 in coordination with the WUS component 1844 of the apparatus 1802 in Figure 18 .

[0156] Alternatively, at 1616, the UE configures the receiver UE to suppress transitioning to the wake state during the second DRX cycle based on not receiving the sidelink WUS within the sidelink WUS monitoring occasion and a second sidelink DRX configuration for sidelink DRX configuration. In Figure 1 and Figures 5 to 15 contexts, for example, UE 104 / 704 may perform suppressing the transition to the wake state after not detecting the sidelink WUS. For example, 1604 may be performed by one or more components (e.g., controller / processor 459) described with reference to Figure 4 Suppressing the transition to the wake state may be performed, for example, by the DRX state transition component 1848 in coordination with the WUS component 1844 of the apparatus 1802 in Figure 18 .

[0157] Figure 17 FIG. 1700 is a flowchart illustrating a process for supporting wireless communication with C-DRX enhancement using a wake signal for sidelink communication at a transmitter UE in accordance with some aspects of the present disclosure. The process may be performed by a UE (e.g., UE 104, 450, 502, 504, 506, 508, 604). As illustrated, flowchart 1700 includes several enumerated steps, but various embodiments of flowchart 1700 may include additional steps before, after, and between these enumerated steps. In some embodiments, one or more of these enumerated steps may be omitted or performed in a different order. Optional aspects are shown with dashed lines.

[0158] At 1702, the UE (e.g., the transmitter UE) may determine a first sidelink DRX configuration to configure the receiver UE to transition to the sleep state when indicating a sidelink WUS. In Figure 1 and Figures 5 to 15 contexts, for example, UE 104 / 702 may determine the first sidelink DRX configuration. For example, 1702 may be performed by one or more components (e.g., controller / processor 459) described with reference to Figure 4 . The first sidelink DRX configuration may be determined, for example, by the determination component 1842 in coordination with the DRX configuration component 1840 of the apparatus 1802 in Figure 18 .

[0159] At 1704, the transmitter UE may determine a second sidelink DRX configuration to configure the receiver UE to transition to the wake state when indicating a sidelink WUS. In Figure 1 and Figures 5 to 15 contexts, for example, UE 104 / 702 may determine the second sidelink DRX configuration. For example, 1704 may be performed by one or more components (e.g., controller / processor 459) described with reference to Figure 4One or more of the described components (e.g., controller / processor 459) execute. The second sidelink DRX configuration may be determined, for example, by the determination component 1842 in coordination with the DRX configuration component 1840 of the device 1802 in Figure 18 to determine.

[0160] At 1706, the transmitter UE may send a sidelink DRX configuration to the receiver UE to configure the receiving UE with the first sidelink DRX configuration or the second sidelink DRX configuration. In Figure 1 and Figures 5 to 15 context, for example, UE 104 / 702 may send a sidelink DRX configuration. For example, 1706 may be performed by one or more of the components described with reference to Figure 4 (e.g., controller / processor 459, transmit processor 468, receiver / transmitter 454, and / or antenna 452). The sidelink DRX configuration may be sent, for example, by the DRX configuration component 1840 via the transmit component 1834 of the device 1802 in Figure 18 .

[0161] At 1708, the UE may send a sidelink WUS to the receiver UE during the sidelink WUS monitoring opportunity in the first DRX cycle based on the sidelink DRX configuration. In Figure 1 and Figures 5 to 15 context, for example, UE 104 / 702 may send a sidelink WUS. For example, 1708 may be performed by one or more of the components described with reference to Figure 4 (e.g., controller / processor 459, transmit processor 468, receiver / transmitter 454, and / or antenna 452). The sidelink WUS may be sent, for example, by the WUS component 1844 via the transmit component 1834 of the device 1802 in Figure 18 .

[0162] Figure 18FIG. 1800 is a diagram illustrating an example of a hardware implementation for apparatus 1802. Apparatus 1802 may be a UE or other wireless device that communicates based on sidelink. Apparatus 1802 includes a cellular baseband processor 1804 (also referred to as a modem) coupled to a cellular RF transceiver 1822 and one or more subscriber identity module (SIM) cards 1820, an application processor 1806 coupled to a secure digital (SD) card 1808 and a screen 1810, a Bluetooth module 1812, a wireless local area network (WLAN) module 1814, a global positioning system (GPS) module 1816, and a power source 1818. The cellular baseband processor 1804 communicates with other wireless devices such as UE 104 and / or base station 102 / 180 via the cellular RF transceiver 1822. The cellular baseband processor 1804 may include computer-readable media / memory. The cellular baseband processor 1804 is responsible for general processing, including executing software stored on the computer-readable media / memory. The software, when executed by the cellular baseband processor 1804, causes the cellular baseband processor 1804 to perform the various functions described above. The computer-readable media / memory may also be used to store data manipulated by the cellular baseband processor 1804 when executing the software. The cellular baseband processor 1804 further includes a receiving component 1830, a sidelink communication manager 1832, and a transmitting component 1834. The sidelink communication manager 1832 includes one or more illustrated components. The components within the sidelink communication manager 1832 may be stored in the computer-readable media / memory and / or configured as hardware within the cellular baseband processor 1804. The cellular baseband processor 1804 may be a component of device 410 or 450 and may include memory 460 or 476 and / or at least one of the following: a TX processor 416 or 468, an RX processor 456 or 470, and a controller / processor 459 or 475. In one configuration, apparatus 1802 may be a modem chip and include only the baseband processor 1804, and in another configuration, apparatus 1802 may be an entire wireless device (e.g., see Figure 4 devices 410 or 450) and include additional modules of apparatus 1802.

[0163] The sidelink communication manager 1832 includes a DRX configuration component 1840, a determination component 1842, a WUS component 1844, a monitoring component 1846, and / or a DRX state transition component 1848 configured to perform aspects described in connection with the procedures in Figure 16 and Figure 17 . The apparatus is illustrated as including components for performing the procedures in Figure 16 and Figure 17 because a wireless device may sometimes operate as a transmitting device and at other times as a receiving device.

[0164] The apparatus 1802 may include additional components for performing each of the blocks of the algorithms in the foregoing flowcharts that perform Figure 16 and 17 . Accordingly, Figure 16 and Figure 17 each block in the foregoing flowcharts may be performed by a component, and the apparatus may include one or more of those components. These components may be one or more hardware components specifically configured to perform the process / algorithm, implemented by a processor configured to perform the process / algorithm, stored in a computer-readable medium for implementation by a processor, or some combination thereof.

[0165] In one configuration, the apparatus 1802 (and specifically the cellular baseband processor 1804) includes components for the following operations: receiving a sidelink DRX configuration from a transmitter UE. The apparatus 1802 may also include components for the following operations: determining whether the receiver UE is configured with a first sidelink DRX configuration or a second sidelink DRX configuration, the first sidelink DRX configuration configuring the receiver UE to transition to a sleep state when a sidelink WUS is indicated, and the second sidelink DRX configuration configuring the receiver UE to transition to a wake state when a sidelink WUS is indicated. The apparatus 1802 may also include components for the following operations: determining whether a sidelink WUS is received within a sidelink WUS monitoring occasion in a first DRX cycle based on the sidelink DRX configuration. The apparatus 1802 may also include components for the following operations: transitioning to a sleep state in a second DRX cycle based on receiving a sidelink WUS within the sidelink WUS monitoring occasion and the sidelink DRX configuration configuring the receiver UE with the first sidelink DRX configuration. The apparatus 1802 may also include components for the following operations: transitioning to a wake state in a second DRX cycle based on receiving a sidelink WUS within the sidelink WUS monitoring occasion and the sidelink DRX configuration configuring the receiver UE with the second sidelink DRX configuration.

[0166] In another configuration, the apparatus 1802 (and specifically the cellular baseband processor 1804) includes components for: determining a first sidelink DRX configuration to configure the receiving UE to transition to a sleep state when a sidelink WUS is indicated. The apparatus 1802 may also include components for: transmitting, via a sidelink channel during at least a portion of the sidelink DRX active duration, a first message to the receiving UE, the first message including an indication of one or more first adjustments to the sidelink DRX configuration. The apparatus 1802 may also include components for: determining a second sidelink DRX configuration to configure the receiving UE to transition to a wake state when a sidelink WUS is indicated. The apparatus 1802 may also include components for: transmitting the sidelink DRX configuration to the receiving UE to configure the receiving UE with the first sidelink DRX configuration or the second sidelink DRX configuration. The apparatus 1802 may also include components for: transmitting a sidelink WUS to the receiving UE based on the sidelink DRX configuration at a sidelink WUS monitoring occasion in a first DRX cycle.

[0167] The foregoing components may be one or more of the foregoing components of the apparatus 1802 configured to perform the functions described by the foregoing components. As described above, the apparatus 1802 may include the TX processor 416 or 468, the RX processor 456 or 470, and the controller / processor 459 or 475. Thus, in one configuration, the foregoing components may be the TX processor 416 or 468, the RX processor 456 or 470, and the controller / processor 459 or 475, which are configured to perform the functions described by the foregoing components.

[0168] The following aspects are illustrative only, and aspects thereof may be combined with aspects of other examples or teachings described herein, but are not limited thereto.

[0169] Aspect 1 is an apparatus for wireless communication at a receiver user equipment (UE), including: a memory; a transceiver; and at least one processor coupled to the memory and the transceiver, the at least one processor being configured to: receive a sidelink discontinuous reception (DRX) configuration from a transmitter UE via the transceiver; determine whether the sidelink DRX configuration configures the receiver UE with a first sidelink DRX configuration or a second sidelink DRX configuration, the first sidelink DRX configuration configuring the receiver UE to transition to a sleep state when a sidelink wake-up signal (WUS) is indicated, and the second sidelink DRX configuration configuring the receiver UE to transition to a wake state when the sidelink WUS is indicated; determine whether the sidelink WUS is received within a sidelink WUS monitoring occasion in a first DRX cycle based on the sidelink DRX configuration; transition to the sleep state in a second DRX cycle based on receiving the sidelink WUS within the sidelink WUS monitoring occasion and the sidelink DRX configuration configuring the receiver UE with the first sidelink DRX configuration; and transition to the wake state in the second DRX cycle based on receiving the sidelink WUS within the sidelink WUS monitoring occasion and the sidelink DRX configuration configuring the receiver UE with the second sidelink DRX configuration.

[0170] In aspect 2, the apparatus according to aspect 1 further includes the at least one processor being further configured to: inhibit transitioning to the sleep state during the second DRX cycle based on not receiving the sidelink WUS within the sidelink WUS monitoring occasion and the sidelink DRX configuration configuring the receiver UE with the first sidelink DRX configuration; and monitor sidelink data during a sidelink DRX on-duration in the second DRX cycle.

[0171] In aspect 3, the apparatus according to any one of aspect 1 or aspect 2 further includes the at least one processor being further configured to: inhibit transitioning to the wake state during the second DRX cycle based on not receiving the sidelink WUS within the sidelink WUS monitoring occasion and the sidelink DRX configuration configuring the receiver UE with the second sidelink DRX configuration.

[0172] In aspect 4, the apparatus according to any one of aspects 1 to 3 further includes the at least one processor being further configured to: determine one or more failures of a listen-before-talk (LBT) procedure before monitoring the sidelink WUS in the first DRX cycle, wherein the inhibition of transitioning to the wake state is further based on the determined one or more failures of the LBT procedure.

[0173] In aspect 5, the apparatus according to any one of aspects 1 to 4 further includes that the at least one processor is further configured to: determine one or more failures of the LBT procedure before monitoring the sidelink WUS in the first DRX cycle, wherein the transition to the wake state occurs regardless of whether the determined one or more failures occur in the LBT procedure.

[0174] In aspect 6, the apparatus according to any one of aspects 1 to 5 further includes that the at least one processor is further configured to: determine that the receiver UE cannot monitor the sidelink WUS in the first DRX cycle before the next sidelink DRX on-duration in the second DRX cycle based on the receiver UE being scheduled to send sidelink communication to a third UE during the sidelink WUS monitoring occasion, wherein the receiver UE assumes that the transmitter UE transmits the sidelink WUS during the sidelink WUS monitoring occasion; transition to the wake state during the second DRX cycle; and monitor sidelink data during the next sidelink DRX on-duration.

[0175] In aspect 7, the apparatus according to any one of aspects 1 to 6 further includes that the receiver UE skips being active during the first sidelink DRX on-duration in the second DRX cycle when the receiver UE transitions to the sleep state, and remains in the sleep state until the second sidelink DRX on-duration in the third DRX cycle.

[0176] In aspect 8, the apparatus according to any one of aspects 1 to 7 further includes that the at least one processor is further configured to: receive sidelink control information (SCI) including the sidelink WUS from the transmitter UE within the sidelink WUS monitoring occasion.

[0177] In aspect 9, the apparatus according to aspect 8 further includes that the SCI includes a transmission structure including the sidelink WUS without data.

[0178] In aspect 10, the apparatus according to aspect 8 further includes that the SCI includes a transmission structure including the sidelink WUS with data.

[0179] In aspect 11, the apparatus according to aspect 10 further includes that the sidelink WUS monitoring occasion is embedded within the sidelink DRX on-duration.

[0180] In aspect 12, the apparatus according to aspect 11 further includes the sidelink DRX configuration configuring a first type of sidelink DRX on-duration and a second type of sidelink DRX on-duration different from the first type of sidelink DRX on-duration, wherein the sidelink DRX configuration indicates which one of the first type of sidelink DRX on-duration or the second type of sidelink DRX on-duration is configured to support micro-slot transmission, and wherein the at least one processor is further configured to monitor the SCI during one or more micro-slots of the sidelink WUS monitoring occasion within the first type of sidelink DRX on-duration or the second type of sidelink DRX on-duration.

[0181] In aspect 13, the apparatus according to aspect 10 further includes the sidelink WUS monitoring occasion being outside the sidelink DRX on-duration within a DRX cycle.

[0182] In aspect 14, the apparatus according to aspect 13 further includes the sidelink DRX configuration configuring the position of the sidelink WUS monitoring occasion by an offset between the start of a sidelink WUS monitoring window and the duration across the sidelink WUS monitoring window, wherein the end of the sidelink WUS monitoring window and the start of the sidelink DRX on-duration are separated by a minimum gap based on the offset and the duration.

[0183] In aspect 15, the apparatus according to aspect 14 further includes the sidelink WUS monitoring window including a plurality of candidate sidelink WUS monitoring occasions, wherein the duration includes a plurality of micro-slots, and wherein each candidate sidelink WUS monitoring occasion among the plurality of candidate sidelink WUS monitoring occasions corresponds to one micro-slot among the plurality of micro-slots.

[0184] In aspect 16, the apparatus according to any one of aspects 1 to 15 further includes the first sidelink DRX configuration being associated with a first type of sidelink DRX on-duration, and the second sidelink DRX configuration being associated with a second type of sidelink DRX on-duration different from the first type of sidelink DRX on-duration.

[0185] In aspect 17, the apparatus according to aspect 16 further includes when the sidelink WUS is received during the first type of sidelink on-duration, the receiving UE transitioning to the sleep state based on the first sidelink DRX configuration.

[0186] In aspect 18, the apparatus according to aspect 16 further includes when the sidelink WUS is received during the second type of sidelink on-duration, the receiving UE transitioning to the wake state based on the second sidelink DRX configuration.

[0187] In aspect 19, the apparatus according to any one of aspects 1 to 18 further comprises that the at least one processor is further configured to: receive the sidelink WUS from the transmitter UE within a first sidelink WUS monitoring occasion, wherein the sidelink WUS indicates to the receiver UE to transition to the sleep state or the wake state within one or more sidelink DRX on durations after the sidelink WUS is indicated; and inhibit monitoring the second sidelink WUS monitoring occasion after the first sidelink WUS monitoring occasion when the sidelink DRX on duration corresponding to the second sidelink WUS monitoring occasion is to transition to the sleep state or the wake state.

[0188] In aspect 20, the apparatus according to aspect 8 further comprises that the SCI includes an indication of a destination identifier to indicate which receiver UE or which group of receiver UEs is to transition to the wake state or the sleep state.

[0189] In aspect 21, the apparatus according to aspect 20 further comprises that the SCI includes a plurality of levels, wherein a second level among the plurality of levels carries one or more information blocks in an order based on the destination identifier of each corresponding receiver UE within a group of receiver UEs, and each of the one or more information blocks is intended for a specific receiver UE within the group of receiver UEs.

[0190] In aspect 22, the apparatus according to aspect 21 further comprises that at least one of the one or more information blocks indicates the sidelink WUS and also indicates a number of bits corresponding to an instance of the sidelink DRX on duration for the specific receiver UE to transition to the sleep state or the wake state.

[0191] In aspect 23, the apparatus according to aspect 22 further comprises that the number of bits is arranged in a bitmap, wherein each position of the bitmap indicates a different number of sidelink DRX on duration instances.

[0192] In aspect 24, the apparatus according to aspect 22 further comprises that the number of bits corresponds to a plurality of indexes, wherein each of the plurality of indexes indicates a different number of sidelink DRX on duration instances.

[0193] In aspect 25, the apparatus according to aspect 22 further comprises that the number of bits is arranged in a start and length indicator value (SLIV), and the start and length indicator value (SLIV) indicates an index for a start sidelink DRX on duration and a plurality of consecutive indexes corresponding to sidelink DRX on duration instances.

[0194] In aspect 26, the apparatus according to aspect 20 further comprises that the SCI comprises a plurality of levels, wherein a third level of the plurality of levels carries one or more information blocks in an order based on the destination identifier of each corresponding receiver UE within a group of receiver UEs, and each of the one or more information blocks is intended for a specific receiver UE within the group of receiver UEs.

[0195] In aspect 27, the apparatus according to aspect 26 further comprises that a second level of the plurality of levels comprises an indication of whether the third level of the plurality of levels is being transmitted.

[0196] In aspect 28, the apparatus according to aspect 20 further comprises that the SCI comprises a plurality of levels, wherein a first level of the plurality of levels comprises an indication of whether an indication of the sidelink WUS is being transmitted.

[0197] In aspect 29, the apparatus according to any one of aspects 1 to 28 further comprises that the sidelink WUS is associated with a fixed resource in every N subchannels, where N is a positive integer, and the sidelink WUS is received on the fixed resource within the sidelink WUS monitoring occasion based on that the sidelink WUS has a first priority higher than a second priority of a reservation of the fixed resource by another transmitter UE.

[0198] In aspect 30, the apparatus according to any one of aspects 1 to 29 further comprises receiving a physical sidelink feedback channel (PSFCH) comprising the sidelink WUS within the sidelink WUS monitoring occasion, wherein the sidelink WUS monitoring occasion is embedded within or outside a sidelink DRX on-duration.

[0199] In aspect 31, the apparatus according to aspect 30 further comprises that a position of the sidelink WUS monitoring occasion is configured by a first PSFCH resource pool, and the first PSFCH resource pool is separate from a second PSFCH resource pool for conflict indication and feedback signaling.

[0200] In aspect 32, the apparatus according to aspect 31 further comprises that the first PSFCH resource pool and the second PSFCH resource pool comprise PSFCH resources having separate physical resource blocks (PRBs), and the sidelink WUS monitoring occasion and the conflict indication and feedback signaling are allocated to the PSFCH in the same time slot using different PRBs.

[0201] In aspect 33, the apparatus according to aspect 31 further includes that the first PSFCH resource pool and the second PSFCH resource pool include PSFCH resources having a plurality of time slots, wherein different numbers of physical resource blocks (PRBs) are used to allocate the sidelink WUS monitoring occasion to the first PSFCH and allocate the conflict indication and the feedback signaling to the second PSFCH in different time slots, and wherein the first PSFCH has a first periodicity greater than a second periodicity of the second PSFCH.

[0202] In aspect 34, the apparatus according to aspect 30 further includes that the position of the sidelink WUS monitoring occasion is configured by a PFSCH resource pool shared with the feedback signaling, and different cyclic shifts are used to allocate the sidelink WUS monitoring occasion and the feedback signaling to the same physical resource block (PRB).

[0203] In aspect 35, the apparatus according to aspect 30 further includes that the PSFCH includes a plurality of sets of physical source blocks (PRBs) divided by a plurality of sidelink DRX on-duration instances, wherein the order of each set of PRBs in the plurality of sets of PRBs is temporally aligned with the corresponding sidelink DRX on-duration instance, and wherein each set of PRBs in the plurality of sets of PRBs includes one or more PRBs mapped based on a destination identifier corresponding to the receiving UE and an indication of the sidelink WUS.

[0204] In aspect 36, the apparatus according to aspect 30 further includes that the sidelink DRX configuration indicates that the sidelink WUS monitoring occasion is located in a PSFCH occasion that is closest in position to the next sidelink DRX on-duration compared to other PSFCH occasions.

[0205] In aspect 37, the apparatus according to aspect 36 further includes that the sidelink DRX configuration indicates that the sidelink WUS monitoring occasion is located in a first PSFCH occasion that is closest in position to the next sidelink DRX on-duration compared to a second PSFCH occasion or in a second PSFCH occasion that is second closest in position to the next sidelink DRX on-duration, and wherein the at least one processor is further configured to monitor the PSFCH in the second PSFCH occasion and monitor the PSFCH in the first PSFCH occasion when the PSFCH is not detected in the second PSFCH occasion.

[0206] Aspect 38 is an apparatus that includes one or more processors and one or more memories that are in electronic communication with the one or more processors, the one or more memories storing instructions executable by the one or more processors to cause the apparatus to implement the apparatus according to any one of Aspects 1 to 37.

[0207] Aspect 39 is a system or apparatus that includes components for implementing the method according to any one of Aspects 1 to 37 or for realizing the apparatus according to the aspect.

[0208] Aspect 40 is a non-transitory computer-readable medium storing instructions executable by one or more processors to cause the one or more processors to implement the apparatus according to any one of Aspects 1 to 37.

[0209] Aspect 41 is a method for realizing the apparatus according to any one of Aspects 1 to 37.

[0210] It should be understood that the specific order or hierarchy of the blocks in the disclosed process / flowchart is an illustration of an exemplary method. It should be understood that the specific order or hierarchy of the blocks in the process / flowchart may be rearranged based on design preferences. Further, some blocks may be combined or omitted. The appended method claims present the elements of the various blocks in a sample order, but are not meant to be limited to the specific order or hierarchy presented.

[0211] The foregoing description is provided to enable any person skilled in the art to practice the various aspects described herein. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other aspects. Thus, the claims are not intended to be limited to the aspects shown herein, but are to be accorded the full scope consistent with the language of the claims, where the elements recited in the singular are not intended to mean "one and only one" but rather "one or more" unless specifically stated otherwise. The word "exemplary" is used herein to mean "serving as an example, instance, or illustration". Any aspect described herein as "exemplary" is not necessarily to be construed as preferred or superior to other aspects. Unless specifically stated otherwise, the term "some" refers to one or more. Combinations such as "at least one of A, B, or C", "one or more of A, B, or C", "at least one of A, B, and C", "one or more of A, B, and C", and "any combination of A, B, C, or their combinations", including any combination of A, B, and / or C, may include multiple A's, multiple B's, or multiple C's. Specifically, combinations such as "at least one of A, B, or C", "one or more of A, B, or C", "at least one of A, B, and C", "one or more of A, B, and C", and "any combination of A, B, C, or their combinations" may be A only, B only, C only, A and B, A and C, B and C, or A and B and C, where any such combination may include one or more members of A, B, or C. All structural and functional equivalents of the elements of the various aspects described throughout this disclosure that are known or later will be known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be covered by the claims. Moreover, nothing disclosed herein is intended to be dedicated to the public, whether or not such disclosure is explicitly recited in the claims. The words "module", "mechanism", "element", "device", etc. shall not be used as a substitute for the word "component". Thus, no claim element shall be construed as a means-plus-function unless the element is expressly recited using the phrase "means for...".

Claims

1. An apparatus for wireless communication at a receiver user equipment (UE), the apparatus comprising: a memory; a transceiver; and at least one processor coupled to the memory and the transceiver, the at least one processor being configured to: receive a sidelink discontinuous reception (DRX) configuration from a transmitter UE via the transceiver; determine whether the sidelink DRX configuration configures the receiver UE with a first sidelink DRX configuration or a second sidelink DRX configuration, the first sidelink DRX configuration configuring the receiver UE to transition to a sleep state when a sidelink wake-up signal (WUS) is indicated, and the second sidelink DRX configuration configuring the receiver UE to transition to a wake state when the sidelink WUS is indicated; determine whether the sidelink WUS is received within a sidelink WUS monitoring occasion in a first DRX cycle based on the sidelink DRX configuration; and transition to the sleep state in a second DRX cycle based on receiving the sidelink WUS within the sidelink WUS monitoring occasion and the sidelink DRX configuration configuring the receiver UE with the first sidelink DRX configuration, or transition to the wake state in the second DRX cycle based on receiving the sidelink WUS within the sidelink WUS monitoring occasion and the sidelink DRX configuration configuring the receiver UE with the second sidelink DRX configuration.

2. The apparatus according to claim 1, wherein the at least one processor is further configured to: suppress transitioning to the sleep state during the second DRX cycle based on not receiving the sidelink WUS within the sidelink WUS monitoring occasion and the sidelink DRX configuration configuring the receiver UE with the first sidelink DRX configuration; and monitor sidelink data during a sidelink DRX on-duration in the second DRX cycle.

3. The apparatus according to claim 1, wherein the at least one processor is further configured to: suppress transitioning to the wake state during the second DRX cycle based on not receiving the sidelink WUS within the sidelink WUS monitoring occasion and the sidelink DRX configuration configuring the receiver UE with the second sidelink DRX configuration.

4. The apparatus according to claim 1, wherein the at least one processor is further configured to: determine that the receiver UE cannot monitor the sidelink WUS in the first DRX cycle before a next sidelink DRX on-duration in the second DRX cycle based on the receiver UE being scheduled to transmit sidelink communication to a third UE during the sidelink WUS monitoring occasion, wherein the receiver UE assumes that the transmitter UE transmits the sidelink WUS during the sidelink WUS monitoring occasion; transition to the wake state during the second DRX cycle; and monitor sidelink data during the next sidelink DRX on-duration.

5. The apparatus according to claim 1, wherein the receiver UE skips being active during a first sidelink DRX on-duration in the second DRX cycle when the receiver UE transitions to the sleep state, and remains in the sleep state until a second sidelink DRX on-duration in a third DRX cycle.

6. The apparatus according to claim 1, wherein the sidelink WUS is associated with fixed resources in every N subchannels, where N is a positive integer, and wherein the sidelink WUS is received on the fixed resources within the sidelink WUS monitoring occasion based on the sidelink WUS having a first priority higher than a second priority of a reservation of the fixed resources by another transmitter UE.

7. The apparatus according to claim 1, wherein the at least one processor is further configured to: receive the sidelink WUS from the transmitter UE within a first sidelink WUS monitoring occasion, wherein the sidelink WUS instructs the receiver UE to transition to the sleep state or the wake state within one or more sidelink DRX on-duration instances after indicating the sidelink WUS; and suppress monitoring the second sidelink WUS monitoring occasion after the first sidelink WUS monitoring occasion when a sidelink DRX on-duration corresponding to the second sidelink WUS monitoring occasion is to transition to the sleep state or the wake state.

8. The apparatus according to claim 1, wherein the at least one processor is further configured to: receive sidelink control information (SCI) including the sidelink WUS from the transmitter UE within the sidelink WUS monitoring occasion.

9. The apparatus according to claim 8, wherein the SCI includes a transmission structure including the sidelink WUS without data.

10. The apparatus according to claim 8, wherein the SCI includes a transmission structure including the sidelink WUS with data.

11. The apparatus according to claim 10, wherein the sidelink WUS monitoring occasion is embedded within a sidelink DRX on-duration, wherein the sidelink DRX configuration configures a first type of sidelink DRX on-duration and a second type of sidelink DRX on-duration different from the first type of sidelink DRX on-duration, and wherein the sidelink DRX configuration indicates which one of the first type of sidelink DRX on-duration or the second type of sidelink DRX on-duration is configured to support micro-slot transmission, and wherein the at least one processor is further configured to: monitor the SCI during one or more micro-slots of the sidelink WUS monitoring occasion within the first type of sidelink DRX on-duration or the second type of sidelink DRX on-duration.

12. The apparatus according to claim 10, wherein the sidelink WUS monitoring occasion is outside of the sidelink DRX on-duration within a DRX cycle.

13. The apparatus according to claim 12, wherein the sidelink DRX configuration configures the position of the sidelink WUS monitoring occasion by an offset between the start of the sidelink WUS monitoring window and the duration across the sidelink WUS monitoring window, wherein the end of the sidelink WUS monitoring window and the start of the sidelink DRX on-duration are separated by a minimum gap based on the offset and the duration, wherein the sidelink WUS monitoring window includes a plurality of candidate sidelink WUS monitoring occasions, wherein the duration includes a plurality of micro-slots, and wherein each candidate sidelink WUS monitoring occasion among the plurality of candidate sidelink WUS monitoring occasions corresponds to one micro-slot among the plurality of micro-slots.

14. The apparatus according to claim 1, wherein the first sidelink DRX configuration is associated with a first type of sidelink DRX on-duration, and the second sidelink DRX configuration is associated with a second type of sidelink DRX on-duration different from the first type of sidelink DRX on-duration.

15. The apparatus according to claim 14, wherein when the sidelink WUS is received during the first type of sidelink on-duration, the receiver UE transitions to the sleep state based on the first sidelink DRX configuration.

16. The apparatus according to claim 14, wherein when the sidelink WUS is received during the second type of sidelink on-duration, the receiver UE transitions to the wake state based on the second sidelink DRX configuration.

17. The apparatus according to claim 8, wherein the SCI includes an indication of a destination identifier to indicate which receiver UE or which group of receiver UEs is to transition to the wake state or the sleep state.

18. The apparatus according to claim 17, wherein the SCI includes a plurality of levels, wherein a second level among the plurality of levels carries one or more information blocks in an order based on the destination identifier of each corresponding receiver UE within a group of receiver UEs, wherein each of the one or more information blocks is intended for a specific receiver UE within the group of receiver UEs, and wherein at least one of the one or more information blocks indicates the sidelink WUS and also indicates a number of bits corresponding to an instance of the sidelink DRX on-duration for the specific receiver UE to transition to the sleep state or the wake state.

19. The apparatus according to claim 18, wherein the number of bits is arranged in a bitmap, and each position of the bitmap indicates a different number of sidelink DRX on-duration instances.

20. The apparatus according to claim 18, wherein the number of bits corresponds to a plurality of indices, and each index among the plurality of indices indicates a different number of sidelink DRX on-duration instances.

21. The apparatus according to claim 18, wherein the number of bits is arranged in a start and length indicator value (SLIV), and the start and length indicator value (SLIV) indicates an index for starting a sidelink DRX on duration and a plurality of consecutive indexes corresponding to sidelink DRX on duration instances.

22. The apparatus according to claim 17, wherein the SCI includes a plurality of levels, and a third level among the plurality of levels carries one or more information blocks in an order based on the destination identifier of each corresponding receiver UE within a group of receiver UEs, wherein each of the one or more information blocks is intended for a specific receiver UE within the group of receiver UEs, and a second level among the plurality of levels includes an indication of whether the third level among the plurality of levels is being transmitted.

23. The apparatus according to claim 17, wherein the SCI includes a plurality of levels, and a first level among the plurality of levels includes an indication of the sidelink WUS.

24. The apparatus according to claim 1, further comprising receiving a physical sidelink feedback channel (PSFCH) including the sidelink WUS within the sidelink WUS monitoring occasion, wherein the sidelink WUS monitoring occasion is embedded within the sidelink DRX on duration or located outside the sidelink DRX on duration.

25. The apparatus according to claim 24, wherein the position of the sidelink WUS monitoring occasion is configured by a first PSFCH resource pool, and the first PSFCH resource pool is separate from a second PSFCH resource pool for conflict indication and feedback signaling.

26. The apparatus according to claim 25, wherein the first PSFCH resource pool and the second PSFCH resource pool include PSFCH resources having separate physical resource blocks (PRBs), and the sidelink WUS monitoring occasion and the conflict indication and feedback signaling are assigned to the PSFCH in the same time slot using different PRBs.

27. The apparatus according to claim 25, wherein the first PSFCH resource pool and the second PSFCH resource pool include PSFCH resources having a plurality of time slots, and the sidelink WUS monitoring occasion is assigned to a first PSFCH and the conflict indication and the feedback signaling are assigned to a second PSFCH in different time slots using different numbers of physical resource blocks (PRBs), and the first PSFCH has a first periodicity greater than a second periodicity of the second PSFCH.

28. The apparatus according to claim 24, wherein the position of the sidelink WUS monitoring occasion is configured by a PFSCH resource pool shared with feedback signaling, and the sidelink WUS monitoring occasion and the feedback signaling are assigned to the same physical resource block (PRB) using different cyclic shift pairs.

29. The apparatus according to claim 24, wherein the PSFCH comprises a plurality of sets of physical resource blocks (PRBs) divided by a plurality of sidelink DRX on-duration instances, wherein the order of each set of the plurality of sets of PRBs is temporally aligned with the corresponding sidelink DRX on-duration instance, and wherein each set of the plurality of sets of PRBs comprises one or more PRBs mapped based on a destination identifier corresponding to the receiver UE and an indication of the sidelink WUS.

30. The apparatus according to claim 24, wherein the sidelink DRX configuration indicates that the sidelink WUS monitoring occasion is located in the PSFCH occasion that is closest in position to the next sidelink DRX on-duration compared to other PSFCH occasions, wherein the sidelink DRX configuration indicates that the sidelink WUS monitoring occasion is located in the first PSFCH occasion that is closest in position to the next sidelink DRX on-duration compared to a second PSFCH occasion or in the second PSFCH occasion that is second closest in position to the next sidelink DRX on-duration, and wherein the at least one processor is further configured to monitor the PSFCH in the second PSFCH occasion and monitor the PSFCH in the first PSFCH occasion when the PSFCH is not detected in the second PSFCH occasion.

31. A method of wireless communication performed by a receiver user equipment (UE), the method comprising: receiving a sidelink discontinuous reception (DRX) configuration from a transmitter UE; determining whether the receiver UE is configured with a first sidelink DRX configuration or a second sidelink DRX configuration, the first sidelink DRX configuration configuring the receiver UE to transition to a sleep state when a sidelink wake-up signal (WUS) is indicated, and the second sidelink DRX configuration configuring the receiver UE to transition to a wake state when the sidelink WUS is indicated; determining whether the sidelink WUS is received within a sidelink WUS monitoring occasion in a first DRX cycle based on the sidelink DRX configuration; and transitioning to the sleep state in a second DRX cycle based on receiving the sidelink WUS within the sidelink WUS monitoring occasion and the sidelink DRX configuration configuring the receiver UE with the first sidelink DRX configuration, or transitioning to the wake state in the second DRX cycle based on receiving the sidelink WUS within the sidelink WUS monitoring occasion and the sidelink DRX configuration configuring the receiver UE with the second sidelink DRX configuration.

32. An apparatus for wireless communication at a transmitter user equipment (UE), the apparatus comprising: a memory; a transceiver; and at least one processor coupled to the memory and the transceiver, the at least one processor being configured to: Determine a first sidelink discontinuous reception (DRX) configuration to configure a receiver UE to transition to a sleep state when a sidelink wake-up signal (WUS) is indicated; Determine a second sidelink DRX configuration to configure the receiver UE to transition to a wake-up state when the sidelink WUS is indicated; And Transmit, via the transceiver, the sidelink DRX configuration to the receiver UE to configure the receiver UE with the first sidelink DRX configuration or the second sidelink DRX configuration, or transmit the sidelink WUS to the receiver UE via the transceiver within a sidelink WUS monitoring occasion in a first DRX cycle based on the sidelink DRX configuration.

33. A method of wireless communication performed by a transmitter user equipment (UE), the method comprising: Determine a first sidelink discontinuous reception (DRX) configuration to configure a receiver UE to transition to a sleep state when a sidelink wake-up signal (WUS) is indicated; Determine a second sidelink DRX configuration to configure the receiver UE to transition to a wake-up state when the sidelink WUS is indicated; And Send the sidelink DRX configuration to the receiver UE to configure the receiver UE with the first sidelink DRX configuration or the second sidelink DRX configuration, or send the sidelink WUS to the receiver UE within a sidelink WUS monitoring occasion in a first DRX cycle based on the sidelink DRX configuration.

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