Discontinuous reception for sidelink communications in wireless communication systems

Abstract

Methods, systems, and devices for wireless communication are described. A user equipment (UE) may transmit side link discontinuous reception (DRX) information to a base station while operating in a connected mode. In some examples, the UE may include sidelink DRX information in UE assistance information (UAI). The sidelink DRX information may include preferences for a DRX cycle, a DRX activity duration, a DRX inactivity duration, or the like of the sidelink DRX operation. The UE may receive a message including a sidelink DRX configuration from the base station based on the sidelink DRX information, and operate according to the sidelink DRX configuration.

Description

[0001] This application is a divisional application of the patent application with the application date of May 17, 2020, the title of "Discontinuous Reception for Sidelink Communication in a Wireless Communication System", and the application number of 202080100301.5. Background Art

[0002] The following relates to wireless communication, and more particularly, the following relates to managing sidelink communication in a wireless communication system.

[0003] Wireless communication systems are widely deployed to provide various types of communication content such as voice, video, packet data, messaging, broadcasting, etc. These systems may be capable of supporting communication with multiple users by sharing available system resources (e.g., time, frequency, and power). Examples of such multi-access systems include fourth-generation (4G) systems such as Long-Term Evolution (LTE) systems, Advanced LTE (LTE-A) systems, or LTE-A Pro systems, and fifth-generation (5G) systems which may be referred to as New Radio (NR) systems. These systems may employ techniques such as Code Division Multiple Access (CDMA), Time Division Multiple Access (TDMA), Frequency Division Multiple Access (FDMA), Orthogonal Frequency Division Multiple Access (OFDMA), or Discrete Fourier Transform Spread Orthogonal Frequency Division Multiplexing (DFT-S-OFDM).

[0004] A wireless multi-access communication system may include one or more base stations or one or more network access nodes, each base station or network access node supporting communication for multiple communication devices (which may also be referred to as user equipment (UE)) simultaneously. Some wireless communication systems may support sidelink communication between multiple communication devices. Examples of sidelink communication may include but are not limited to device-to-device (D2D) communication, vehicle-based communication (which may also be referred to as vehicle-to-everything (V2X) communication system), vehicle-to-vehicle (V2V) communication system, cellular V2X (C-V2X) communication system, etc. Summary of the Invention

[0005] A wireless communication method at a UE is described. The method may include: sending sidelink DRX (DRX) information to a base station when operating in a connected mode, receiving, based on the sidelink DRX information, a message including a sidelink DRX configuration from the base station, and operating according to the sidelink DRX configuration.

[0006] A device for wireless communication is described. The device may include a processor and a memory coupled to the processor, the processor and the memory being configured to: send sidelink DRX information to a base station when operating in a connected mode, receive a message including a sidelink DRX configuration from the base station based on the sidelink DRX information, and operate according to the sidelink DRX configuration.

[0007] Another device for wireless communication is described. The device may include units for performing the following operations: sending sidelink DRX information to a base station when operating in a connected mode, receiving a message including a sidelink DRX configuration from the base station based on the sidelink DRX information, and operating according to the sidelink DRX configuration.

[0008] A non-transitory computer-readable medium storing code for wireless communication at a UE is described. The code may include instructions executable by a processor to perform the following operations: send sidelink DRX information to a base station when operating in a connected mode, receive a message including a sidelink DRX configuration from the base station based on the sidelink DRX information, and operate according to the sidelink DRX configuration.

[0009] Some examples of the methods, devices, and non-transitory computer-readable media described herein may further include operations, features, units, or instructions for the following: monitoring a sidelink channel to receive a discovery signal from a second UE during an active duration of a DRX cycle based on the sidelink DRX configuration; and receiving the discovery signal from the second UE based on the monitoring.

[0010] In some examples of the methods, devices, and non-transitory computer-readable media described herein, the sidelink DRX configuration may be based on a discovery resource pool corresponding to time and frequency resources associated with monitoring the sidelink channel to receive the discovery signal from the second UE.

[0011] Some examples of the methods, devices, and non-transitory computer-readable media described herein may further include operations, features, units, or instructions for the following: broadcasting a discovery request message during the active duration of the DRX cycle based on the sidelink DRX configuration; monitoring the sidelink channel during the active duration of the DRX cycle to receive a discovery response message from the second UE; and receiving the discovery response message from the second UE based on the monitoring, the discovery signal including the discovery response message.

[0012] Some examples of the methods, apparatuses, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions for: selecting the second UE for relay communication between the UE and the base station or between the UE and a third UE or both, based on the discovery signal, wherein the relay communication corresponds to a layer 2 (L2) forwarding function or a layer 3 (L3) forwarding function.

[0013] Some examples of the methods, apparatuses, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions for: determining a sidelink DRX mode for monitoring the sidelink channel to receive the discovery signal from the second UE, based on the sidelink DRX configuration, the sidelink DRX mode including the DRX cycle, the DRX cycle including the active duration and the inactive duration.

[0014] Some examples of the methods, apparatuses, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions for: receiving a synchronization signal from the second UE on a sidelink broadcast channel; and synchronizing with the second UE based on the synchronization signal.

[0015] Some examples of the methods, apparatuses, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions for: receiving a downlink signal from the base station using a cellular link, based on the sidelink DRX configuration; or transmitting an uplink signal to the base station using the cellular link, based on the sidelink DRX configuration.

[0016] Some examples of the methods, apparatuses, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions for: determining a sidelink DRX mode for receiving the downlink signal or transmitting the uplink signal or both, based on the sidelink DRX configuration, the sidelink DRX mode including a DRX cycle, the DRX cycle including an active duration and an inactive duration, wherein receiving the downlink signal or transmitting the uplink signal or both may be based on the sidelink DRX mode.

[0017] In some examples of the methods, apparatuses, and non-transitory computer-readable media described herein, receiving the message may include operations, features, units, or instructions for: receiving a radio resource control (RRC) reconfiguration message including the sidelink DRX configuration from the base station.

[0018] Some examples of the methods, apparatuses, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions for: sending an RRC reconfiguration complete message to the base station based on the RRC reconfiguration message, wherein operating according to the sidelink DRX configuration may be based on the RRC reconfiguration complete message.

[0019] Some examples of the methods, apparatuses, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions for: including the sidelink DRX information in UE assistance information (UAI), and sending the UAI including the sidelink DRX information to the base station when operating in the connected mode, wherein receiving the message including the sidelink DRX configuration may be based on the UAI.

[0020] Some examples of the methods, apparatuses, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions for: determining a single connection mode DRX cycle for sidelink communication or cellular communication or both based on the sidelink DRX configuration, and wherein operating according to the sidelink DRX configuration may be based on the single connection mode DRX cycle.

[0021] Some examples of the methods, apparatuses, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions for: determining a DRX cycle based on a relay service associated with a second UE or a quality of service (QoS) associated with the UE's data traffic or both, wherein the sidelink DRX information includes an indication of the DRX cycle.

[0022] Some examples of the methods, apparatuses, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions for: determining a value of an active timer associated with the DRX cycle based on a relay service associated with a second UE or a QoS associated with the UE's data traffic or both, wherein the sidelink DRX information includes an indication of the value of the active timer associated with the DRX cycle.

[0023] Some examples of the methods, apparatuses, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions for: determining a value of an inactivity timer associated with the DRX cycle based on a relay service associated with a second UE or a QoS associated with the UE's data traffic or both, wherein the sidelink DRX information includes an indication of the value of the inactivity timer associated with the DRX cycle.

[0024] Some examples of the methods, apparatuses, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions for: determining an offset between a start of a DRX cycle and a start of an active duration of the DRX cycle based on a relay service associated with a second UE or a QoS associated with data traffic of the UE or both, wherein the sidelink DRX information includes an indication of the offset.

[0025] Some examples of the methods, apparatuses, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions for: determining a first sidelink DRX mode associated with the sidelink DRX configuration for monitoring a sidelink channel to receive a discovery signal based on the sidelink DRX configuration; determining a second sidelink DRX mode associated with the sidelink DRX configuration for receiving a downlink signal from the base station or transmitting an uplink signal to the base station or both based on the sidelink DRX configuration, wherein the first sidelink DRX mode may be different from the second sidelink DRX mode.

[0026] In some examples of the methods, apparatuses, and non-transitory computer-readable media described herein, the sidelink DRX configuration includes a first indication of the first sidelink DRX mode or a second indication of the second sidelink DRX mode, or both.

[0027] In some examples of the methods, apparatuses, and non-transitory computer-readable media described herein, the sidelink DRX configuration includes a connected-mode DRX configuration.

[0028] In some examples of the methods, apparatuses, and non-transitory computer-readable media described herein, the sidelink DRX configuration includes a sidelink DRX preference associated with a discovery process including a first model discovery process or a second model discovery process.

[0029] In some examples of the methods, apparatuses, and non-transitory computer-readable media described herein, the sidelink DRX configuration includes a sidelink DRX preference associated with receiving a downlink signal from the base station or transmitting an uplink signal to the base station or both.

[0030] In some examples of the methods, apparatuses, and non-transitory computer-readable media described herein, the UE includes a remote UE, and the second UE includes a relay UE between the remote UE and the base station.

[0031] Describes a wireless communication method at a UE. The method may include: when operating in an out-of-coverage mode, an idle mode, or an inactive mode, receiving a message including a group sidelink DRX configuration associated with a group of UEs; determining a time period during which discontinuous monitoring of a sidelink channel can be performed based on the group sidelink DRX configuration; and monitoring the sidelink channel during the time period.

[0032] Describes an apparatus for wireless communication. The apparatus may include a processor and a memory coupled to the processor, the processor and the memory being configured to: when operating in an out-of-coverage mode, an idle mode, or an inactive mode, receive a message including a group sidelink DRX configuration associated with a group of apparatuses; determine a time period during which discontinuous monitoring of a sidelink channel can be performed based on the group sidelink DRX configuration; and monitor the sidelink channel during the time period.

[0033] Describes another apparatus for wireless communication. The apparatus may include units for performing the following operations: when operating in an out-of-coverage mode, an idle mode, or an inactive mode, receive a message including a group sidelink DRX configuration associated with a group of apparatuses; determine a time period during which discontinuous monitoring of a sidelink channel can be performed based on the group sidelink DRX configuration; and monitor the sidelink channel during the time period.

[0034] Describes a non-transitory computer-readable medium storing code for wireless communication at a UE. The code may include instructions executable by a processor to perform the following operations: when operating in an out-of-coverage mode, an idle mode, or an inactive mode, receive a message including a group sidelink DRX configuration associated with a group of UEs; determine a time period during which discontinuous monitoring of a sidelink channel can be performed based on the group sidelink DRX configuration; and monitor the sidelink channel during the time period.

[0035] In some examples of the methods, apparatuses, and non-transitory computer-readable media described herein, receiving the message may include operations, features, units, or instructions for: receiving a system information block (SIB) or an RRC reconfiguration message including the group sidelink DRX configuration.

[0036] Some examples of the methods, apparatuses, and non-transitory computer-readable media described herein may further include operations, features, units, or instructions for: enabling discontinuous monitoring of the sidelink channel based on the SIB or the RRC reconfiguration message.

[0037] Some examples of the methods, apparatuses, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions for: disabling the DRX mode based on meeting a QoS threshold associated with outstanding data traffic.

[0038] In some examples of the methods, apparatuses, and non-transitory computer-readable media described herein, the group sidelink DRX configuration includes a DRX period common to the group of UEs.

[0039] In some examples of the methods, apparatuses, and non-transitory computer-readable media described herein, the sidelink DRX configuration includes an active duration of the DRX period common to the group of UEs.

[0040] In some examples of the methods, apparatuses, and non-transitory computer-readable media described herein, the sidelink DRX configuration includes a group offset duration between the start of the DRX period and the active duration of the DRX period, where the group offset duration may be common to the group of UEs.

[0041] In some examples of the methods, apparatuses, and non-transitory computer-readable media described herein, the time period may be common to the group of UEs.

[0042] In some examples of the methods, apparatuses, and non-transitory computer-readable media described herein, the UEs may be grouped in the group of UEs based on a path loss parameter.

[0043] In some examples of the methods, apparatuses, and non-transitory computer-readable media described herein, the UEs may be grouped into the group of UEs based on the QoS associated with the data traffic of the UEs.

[0044] Some examples of the methods, apparatuses, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions for: determining a UE-specific offset duration associated with the active duration of a DRX period based on the sidelink DRX configuration, where monitoring the sidelink channel includes.

[0045] In some examples of the methods, apparatuses, and non-transitory computer-readable media described herein, the UE-specific offset duration may be based on a layer 2 (L2) identifier associated with the UE.

[0046] Some examples of the methods, apparatuses, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions for: enabling the DRX mode based on the message.

[0047] Some examples of the methods, apparatuses, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions for: enabling a DRX mode based on meeting a QoS threshold associated with a pending data service.

[0048] Some examples of the methods, apparatuses, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions for: enabling a DRX mode based on a power level of the UE meeting a power level threshold.

[0049] Some examples of the methods, apparatuses, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions for: avoiding monitoring one or more resource pools during an inactive duration of a DRX cycle based on the group sidelink DRX configuration.

[0050] Some examples of the methods, apparatuses, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions for: avoiding monitoring one or more resource pools associated with monitoring the sidelink channel for a discovery signal based on a group resource pool configuration associated with monitoring the discovery signal.

[0051] Some examples of the methods, apparatuses, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions for: broadcasting a discovery request message during an inactive duration of a DRX cycle associated with the group of UEs based on a data service condition of the UE, wherein the inactive duration may be common for the group of UEs, and wherein the inactive duration and the DRX cycle may be common for the group of UEs.

[0052] Some examples of the methods, apparatuses, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions for: receiving a downlink signal from a base station during an inactive duration of a DRX cycle associated with the group of UEs; or, and sending an uplink signal to the base station during an inactive duration of a DRX cycle associated with the group of UEs, wherein the inactive duration and the DRX cycle may be common for the group of UEs.

[0053] Some examples of the methods, apparatuses, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions for: synchronizing with the group of UEs based on a synchronization signal received from at least one UE associated with the group of UEs on a sidelink broadcast channel.

[0054] A wireless communication method is described. The method may include: determining a DRX cycle based on a sidelink DRX configuration, the DRX cycle including an active duration and an inactive duration; receiving a discovery request message from a second UE during the active duration of the DRX cycle; and sending a discovery response message to the second UE during the active duration of the DRX cycle.

[0055] A device for wireless communication is described. The device may include a processor and a memory coupled to the processor, the processor and the memory being configured to: determine a DRX cycle based on a sidelink DRX configuration, the DRX cycle including an active duration and an inactive duration; receive a discovery request message from a second UE during the active duration of the DRX cycle; and send a discovery response message to the second UE during the active duration of the DRX cycle.

[0056] Another device for wireless communication is described. The device may include units for performing the following operations: determining a DRX cycle based on a sidelink DRX configuration, the DRX cycle including an active duration and an inactive duration; receiving a discovery request message from a second UE during the active duration of the DRX cycle; and sending a discovery response message to the second UE during the active duration of the DRX cycle.

[0057] A non-transitory computer-readable medium storing code for wireless communication at a UE is described. The code may include instructions executable by a processor for performing the following operations: determining a DRX cycle based on a sidelink DRX configuration, the DRX cycle including an active duration and an inactive duration; receiving a discovery request message from a second UE during the active duration of the DRX cycle; and sending a discovery response message to the second UE during the active duration of the DRX cycle.

[0058] In some examples of the methods, devices, and non-transitory computer-readable media described herein, the sidelink DRX configuration may be based on a discovery resource pool corresponding to the time and frequency resources for receiving the discovery request message or sending the discovery response message or both.

[0059] Some examples of the methods, devices, and non-transitory computer-readable media described herein may further include operations, features, units, or instructions for the following: establishing a connection with the second UE to relay communication for the UE, wherein the relayed communication corresponds to an L2 forwarding function or an L3 forwarding function.

[0060] Some examples of the methods, apparatuses, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions for: sending a synchronization signal to the second UE on a sidelink broadcast channel; and synchronizing with the second UE based on the synchronization signal.

[0061] A wireless communication method at a base station is described. The method may include: receiving sidelink DRX information from a UE; determining a sidelink DRX mode for the UE based on the sidelink DRX information; and sending a message including a sidelink DRX configuration, the sidelink DRX configuration including an indication of the sidelink DRX mode for the UE.

[0062] A device for wireless communication is described. The device may include a processor and a memory coupled to the processor, the processor and the memory being configured to: receive sidelink DRX information from a UE; determine a sidelink DRX mode for the UE based on the sidelink DRX information; and send a message including a sidelink DRX configuration, the sidelink DRX configuration including an indication of the sidelink DRX mode for the UE.

[0063] Another device for wireless communication is described. The device may include units for performing the following operations: receiving sidelink DRX information from a UE; determining a sidelink DRX mode for the UE based on the sidelink DRX information; and sending a message including a sidelink DRX configuration, the sidelink DRX configuration including an indication of the sidelink DRX mode for the UE.

[0064] A non-transitory computer-readable medium storing code for wireless communication at a base station is described. The code may include instructions executable by a processor for performing the following operations: receiving sidelink DRX information from a UE; determining a sidelink DRX mode for the UE based on the sidelink DRX information; and sending a message including a sidelink DRX configuration, the sidelink DRX configuration including an indication of the sidelink DRX mode for the UE.

[0065] In some examples of the methods, apparatuses, and non-transitory computer-readable media described herein, sending the message may include operations, features, units, or instructions for: sending an RRC reconfiguration message including the sidelink DRX configuration to the UE.

[0066] Some examples of the methods, apparatuses, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions for: receiving, at the base station, an RRC reconfiguration complete message based on the RRC reconfiguration message.

[0067] Some examples of the methods, apparatuses, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions for: receiving, from the UE, a UAI including the sidelink DRX information.

[0068] Some examples of the methods, apparatuses, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions for: determining, based on a resource pool configuration for the UE, the sidelink DRX mode for the UE.

[0069] Some examples of the methods, apparatuses, and non-transitory computer-readable media described herein may also include operations, features, units, or instructions for: determining, based on the sidelink DRX information, a first sidelink DRX mode associated with the sidelink DRX configuration for monitoring a sidelink channel for discovery signals at the UE; and determining, based on the sidelink DRX information, a second sidelink DRX mode associated with the sidelink DRX configuration for receiving a downlink signal from the base station at the UE, wherein the first sidelink DRX mode may be different from the second sidelink DRX mode.

[0070] In some examples of the methods, apparatuses, and non-transitory computer-readable media described herein, the sidelink DRX configuration includes a connected mode DRX configuration.

[0071] In some examples of the methods, apparatuses, and non-transitory computer-readable media described herein, the sidelink DRX configuration includes a sidelink DRX preference. BRIEF DESCRIPTION OF THE DRAWINGS

[0072] Figure 1 and Figure 2 illustrate examples of wireless communication systems in accordance with one or more aspects of the present disclosure.

[0073] Figure 3 illustrate examples of process flows in accordance with one or more aspects of the present disclosure.

[0074] Figures 4 to 7 illustrate examples of timelines in accordance with one or more aspects of the present disclosure.

[0075] Figure 8 and Figure 9A block diagram of a device in accordance with one or more aspects of the present disclosure is shown.

[0076] Figure 10 A block diagram of a UE communication manager in accordance with one or more aspects of the present disclosure is shown.

[0077] Figure 11 A diagram of a system including a device in accordance with one or more aspects of the present disclosure is shown.

[0078] Figure 12 and Figure 13 A block diagram of a device in accordance with one or more aspects of the present disclosure is shown.

[0079] Figure 14 A block diagram of a base station communication manager in accordance with one or more aspects of the present disclosure is shown.

[0080] Figure 15 A diagram of a system including a device in accordance with one or more aspects of the present disclosure is shown.

[0081] Figures 16 to 19 A flowchart illustrating a method in accordance with one or more aspects of the present disclosure is shown. DETAILED DESCRIPTION

[0082] A wireless communication system may include a plurality of communication devices, such as UEs and base stations, which may provide wireless communication services to other UEs. For example, a base station may be a next-generation node B or a giga node B (both may be referred to as a gNB), which may support multiple radio access technologies, including 4G systems (e.g., LTE systems) as well as 5G systems, which may be referred to as NR systems. Some wireless communication systems may also support sidelink communication between multiple UEs. Examples of sidelink communication may include, but are not limited to, D2D communication, vehicle-based communication, which may also be referred to as a V2X communication system, a V2V communication system, etc. Some wireless communication systems may support relay operation to extend network coverage for UEs.

[0083] A UE can communicate directly with a network device (e.g., a network operator of a network (e.g., a 4G network, a 5G network)). Alternatively, a UE can communicate indirectly with a network device through another UE (also referred to as a relay UE). For example, a UE and a base station may not be able to communicate directly because the UE may be outside the coverage area of the base station, so a relay UE is needed to relay the communication between the UE and the base station. A UE outside the coverage area can be referred to as a remote UE in this document. As described herein, a remote UE can discover a relay UE based on discovery messages (also referred to as discovery signals) broadcast from the relay UE and received at the remote UE. In another example, a remote UE can advertise a sidelink discovery request message to which the relay UE can respond. These discovery messages can include certain information that the remote UE or the relay UE or both can use to establish a sidelink (also referred to as a sidelink connection) for relaying transmissions to and from the base station, e.g., for sending and receiving information related to services provided by the base station. In some cases, a remote UE seeking to discover a relay UE to act as a repeater may consume unnecessary power when monitoring discovery messages. As a result, the battery life of the remote UE may be affected, which may also affect the reliability and latency of receiving service-related information at the remote UE.

[0084] Aspects of the described techniques involve configuring a remote UE to operate in a power saving mode (also referred to as DRX mode) to reduce its power consumption when discovering and selecting a relay UE as a repeater between the remote UE and the base station. When in the power saving mode, the remote UE can power on appropriate circuitry for a period of time to monitor a wireless channel for discovery messages from other UEs. After that period elapses, the remote UE can power off for a period of time. The power saving mode, including the periods for powering on and off, can be specific to when the remote UE monitors for discovery messages of candidate relay UEs. Upon detecting a candidate relay UE, based on the discovery message, the remote UE can select the candidate relay UE as a repeater based on the sidelink quality meeting a threshold or the candidate relay UE can provide a connection service requested by the remote UE, etc. The remote UE can evaluate the former condition by performing measurements on the discovery message received from the candidate relay UE, and it checks the latter condition by referring to fields (e.g., relay service code) included in the discovery message provided by the candidate relay UE.

[0085] The period associated with the power saving mode can be configured and provided by the base station based on information provided by the remote UE. For example, the remote UE can provide DRX preferences indicating preferences for one or more DRX parameters, which include DRX cycle, active duration of the DRX cycle, inactive duration of the DRX cycle, DRX period, periodicity of the DRX cycle, offset period associated with the active duration of the DRX cycle, DRX inactive timer, DRX active timer, DRX retransmission timer, and so on. In some cases, the remote UE can belong to a group of UEs, and this group of UEs can share the configuration for the power saving mode (e.g., sidelink DRX configuration). To avoid interference between UEs in the group, each UE can have an offset period indicating when to power on and off as indicated in the configuration. Thus, for sidelink communication, since relay selection and discovery are supported according to the power saving mode (e.g., using sidelink DRX configuration for sidelink communication and relay monitoring and discovery), the UE can experience power saving.

[0086] Aspects of the subject matter described in this disclosure can be implemented to achieve one or more of the following potential improvements and other improvements. The techniques employed by the UE can provide benefits and enhancements to the operation of the UE. For example, the operations performed by the UE can provide power saving improvements for the UE. In some examples, configuring the UE to support sidelink DRX for relay discovery and selection can reduce the power consumption of the UE.

[0087] Aspects of the present disclosure are first described in the context of a wireless communication system. Aspects of the present disclosure are further illustrated and described with reference to apparatus diagrams, system diagrams, and flowcharts related to managing DRX for sidelink communication in a wireless communication system to select relay devices.

[0088] Figure 1 An example of a wireless communication system 100 according to one or more aspects of the present disclosure is illustrated. The wireless communication system 100 can include one or more base stations 105, one or more UEs 115, and a core network 130. In some examples, the wireless communication system 100 can be an LTE network, an advanced LTE (LTE-A) network, an LTE-A Pro network, or an NR network. In some examples, the wireless communication system 100 can support enhanced broadband communication, ultra-reliable (e.g., mission-critical) communication, low-latency communication, communication with low-cost and low-complexity devices, or any combination thereof.

[0089] Base stations 105 may be dispersed throughout a geographical area to form a wireless communication system 100 and may be devices having different forms or having different capabilities. The base stations 105 and the UEs 115 may communicate wirelessly via one or more communication links 125. Each base station 105 may provide a coverage area 110, and the UEs 115 and the base stations 105 may establish one or more communication links 125 over the coverage area 110. The coverage area 110 may be an example of a geographical area over which the base stations 105 and the UEs 115 may support communication of signals according to one or more radio access technologies.

[0090] The UEs 115 may be dispersed throughout the coverage area of the wireless communication system 100, and each UE 115 may be stationary, mobile, or stationary or mobile at different times. The UEs 115 may be devices having different forms or having different capabilities. Figure 1 Some example UEs 115 are illustrated. The UEs 115 described herein may be capable of communicating with various types of devices, such as other UEs 115, base stations 105, or network devices (e.g., core network nodes, relay devices, integrated access and backhaul (IAB) nodes, or other network devices), as Figure 1 shown.

[0091] The base stations 105 may communicate with the core network 130, communicate with each other, or do both. For example, the base stations 105 may interface with the core network 130 via one or more backhaul links 120 (e.g., via S1, N2, N3, or other interfaces). The base stations 105 may communicate with each other directly (e.g., directly between base stations 105), indirectly (e.g., via the core network 130), or both via the backhaul links 120 (e.g., via X2, Xn, or other interfaces). In some examples, the backhaul links 120 may be or include one or more wireless links. The UEs 115 may communicate with the core network 130 via a communication link 155. One or more of the base stations 105 described herein may include or may be referred to by those of ordinary skill in the art as base station transceivers, radio base stations, access points, radio transceivers, Node Bs, eNodeBs (eNBs), next-generation Node Bs, or Gigabit Node Bs (any of which may be referred to as gNBs), home Node Bs, home eNodeBs, or other suitable terms.

[0092] The UE 115 may include or may be referred to as a mobile device, wireless device, remote device, handheld device, or subscriber device, or some other suitable term, where "device" may also be referred to as a unit, station, terminal, or client, among other examples. The UE 115 may also include or may be referred to as a personal electronic device, such as a cellular phone, personal digital assistant (PDA), tablet computer, laptop computer, or personal computer. In some examples, the UE 115 may include or be referred to as a wireless local loop (WLL) station, Internet of Things (IoT) device, Internet of Everything (IoE) device, or machine type communication (MTC) device, among other examples, which may be implemented in various objects such as appliances, or vehicles, meters, and other examples. The UE 115 described herein may be capable of communicating with various types of devices, such as other UE 115s that may sometimes be used as repeaters, as well as the base station 105 and network devices, which include, for example, Figure 1 the macro eNB or gNB, small cell eNB or gNB, or relay base station, as shown, among other examples.

[0093] The UE 115 and the base station 105 may wirelessly communicate with each other via one or more communication links 125 over one or more carriers. The term "carrier" may refer to a collection of radio frequency spectrum resources having a defined physical layer structure for supporting the communication link 125. For example, a carrier for the communication link 125 may include a portion (e.g., bandwidth part (BWP)) of a radio frequency spectrum band that operates according to one or more physical layer channels for a given radio access technology (e.g., LTE, LTE-A, LTE-A Pro, NR). Each physical layer channel may carry acquisition signaling (e.g., synchronization signals, system information), control signaling for coordinating the operation of the carrier, user data, or other signaling. The wireless communication system 100 may use carrier aggregation or multi-carrier operation to support communication with the UE 115. The UE 115 may be configured with multiple downlink component carriers and one or more uplink component carriers according to a carrier aggregation configuration. Carrier aggregation may utilize both frequency division duplex (FDD) and time division duplex (TDD) component carriers.

[0094] In some examples (e.g., in a carrier aggregation configuration), a carrier may also have control signaling that captures signaling or coordinates the operation of other carriers. A carrier may be associated with a frequency channel (e.g., an evolved universal mobile telecommunications system terrestrial radio access (E-UTRA) absolute radio frequency channel number (EARFCN)) and may be positioned according to a channel raster for discovery by UE 115. A carrier may operate in an independent mode, where UE 115 may perform initial acquisition and connection via the carrier, or a carrier may operate in a non-independent mode, where a different carrier (e.g., of the same or different radio access technology) is used to anchor the connection.

[0095] The communication link 125 shown in the wireless communication system 100 may include: an uplink transmission from UE 115 to the base station 105, or a downlink transmission from the base station 105 to UE 115. A carrier may carry downlink or uplink communication (e.g., in FDD mode), or may be configured to carry both downlink and uplink communication (e.g., in TDD mode).

[0096] A carrier may be associated with a particular bandwidth of the radio frequency spectrum, and in some examples, the carrier bandwidth may be referred to as the "system bandwidth" of the carrier or the wireless communication system 100. For example, the carrier bandwidth may be one of a plurality of determined bandwidths of carriers of a particular radio access technology (e.g., 1.4, 3, 5, 10, 15, 20, 40, or 80 megahertz (MHz)). Devices of the wireless communication system 100 (e.g., base station 105, UE 115, or both) may have a hardware configuration that supports communication on a particular carrier bandwidth, or may be configurable to support communication on one of a set of carrier bandwidths. In some examples, the wireless communication system 100 may include a base station 105 or UE 115 that supports simultaneous communication via carriers associated with multiple carrier bandwidths. In some examples, each served UE 115 may be configured to operate on a portion (e.g., a subband, BWP) or all of the carrier bandwidth.

[0097] The signal waveform transmitted on a carrier can be composed of multiple subcarriers (e.g., using multi-carrier modulation (MCM) techniques such as orthogonal frequency division multiplexing (OFDM) or discrete Fourier transform spread OFDM (DFT-S-OFDM)). In a system employing MCM techniques, a resource unit can consist of a symbol period (e.g., the duration of a modulated symbol) and a subcarrier, where the symbol period and subcarrier spacing are inversely related. The number of bits carried by each resource unit can depend on the modulation scheme (e.g., the order of the modulation scheme, the coding rate of the modulation scheme, or both). Therefore, the more resource units received by UE 115 and the higher the order of the modulation scheme, the higher the data rate of UE 115 can be. Wireless communication resources can refer to a combination of radio frequency spectrum resources, time resources, and spatial resources (e.g., spatial layers or beams), and the use of multiple spatial layers can also increase the data rate or data integrity for communicating with UE 115.

[0098] One or more numerology for a carrier can be supported, where the numerology can include subcarrier spacing (Δf) and cyclic prefix. A carrier can be divided into one or more BWPs with the same or different numerology. In some examples, UE 115 can be configured with multiple BWPs. In some examples, a single BWP of a carrier can be active at a given time, and the communication for UE 115 can be restricted to one or more active BWPs.

[0099] The time intervals of base station 105 or UE 115 can be expressed as multiples of a basic time unit, which, for example, can refer to T s = 1 / (Δf max .N f ) seconds of sampling period, where Δf max can represent the maximum supported subcarrier spacing, and N f can represent the maximum supported discrete Fourier transform (DFT) size. The time intervals of communication resources can be organized according to radio frames, each radio frame having a specified duration (e.g., 10 milliseconds (ms)). Each radio frame can be identified by a system frame number (SFN) (e.g., ranging from 0 to 1023).

[0100] Each frame may include a plurality of consecutively numbered sub - frames or time slots, and each sub - frame or time slot may have the same duration. In some examples, a frame may be divided (e.g., in the time domain) into sub - frames, and each sub - frame may be further divided into a plurality of time slots. Alternatively, each frame may include a variable number of time slots, and the number of time slots may depend on the sub - carrier spacing. Each time slot may include a plurality of symbol periods (e.g., depending on the length of the cyclic prefix before each symbol period). In some wireless communication systems 100, a time slot may be further divided into a plurality of mini - time slots each containing one or more symbols. Excluding the cyclic prefix, each symbol period may contain one or more (e.g., N f f

[0101] sub - frames, time slots, mini - time slots, or symbols may be the smallest scheduling unit (e.g., in the time domain) of the wireless communication system 100 and may be referred to as a transmission time interval (TTI). In some examples, the TTI duration (e.g., the number of symbol periods in a TTI) may be variable. Additionally or alternatively, the smallest scheduling unit of the wireless communication system 100 may be dynamically selected (e.g., in a burst of shortened TTIs (sTTIs)).

[0102] Physical channels may be multiplexed on a carrier according to various techniques. For example, using one or more of time - division multiplexing (TDM) techniques, frequency - division multiplexing (FDM) techniques, or hybrid TDM - FDM techniques, physical control channels and physical data channels may be multiplexed on a downlink carrier. A control region (e.g., a control resource set (CORESET)) for a physical control channel may be defined by the number of symbol periods and may extend across the system bandwidth of the carrier or a subset of the system bandwidth of the carrier. One or more control regions (e.g., CORESETs) may be configured for a set of UEs 115. For example, one or more UEs 115 may monitor or search a control region for control information according to one or more search space sets, and each search space set may include one or more control channel candidates at one or more aggregation levels arranged in a cascaded manner. The aggregation level for a control channel candidate may refer to a plurality of control channel resources (e.g., control channel elements (CCEs)) associated with the coded information for a control information format having a given payload size. The search space set may include a common search space set configured to send control information to a plurality of UEs 115 and a UE - specific search space set for sending control information to a particular UE 115.

[0103] Each base station 105 may provide communication coverage via one or more cells (e.g., macro cells, small cells, hotspots, or other types of cells or any combination thereof). The term "cell" refers to a logical communication entity for communicating with the base station 105 (e.g., via a carrier), and may be associated with an identifier (e.g., physical cell identifier (PCID), virtual cell identifier (VCID), or others) for differentiating adjacent cells. In some examples, a cell may also refer to the geographic coverage area 110 or a portion (e.g., a sector) of the geographic coverage area 110 on which the logical communication entity operates. The scope of such a cell may range from a smaller area (e.g., a structure, a subset of a structure) to a larger area, depending on various factors (e.g., the capabilities of the base station 105). For example, a cell may be or include a building, a subset of a building, or an external space between or overlapping with the geographic coverage area 110, among other examples.

[0104] Macro cells cover a relatively large geographic area (e.g., with a radius of several kilometers) and may allow unrestricted access to UEs 115 having a service subscription to the network provider supporting the macro cell. In comparison with macro cells, small cells may be associated with low-power base stations 105, and small cells may operate in the same or a different (e.g., licensed, unlicensed) frequency band as macro cells. Small cells may provide unrestricted access to UEs 115 having a service subscription to the network provider, or may provide restricted access to UEs 115 associated with the small cell (e.g., UEs 115 in a closed subscriber group (CSG), UEs 115 associated with users in a home or office). The base station 105 may support one or more cells and may also use one or more component carriers to support communication on one or more cells. In some examples, a carrier may support multiple cells, and different cells may be configured according to different protocol types (e.g., MTC, narrowband IoT (NB-IoT), enhanced mobile broadband (eMBB)) that may provide access rights for different types of devices.

[0105] In some examples, the base station 105 may be movable and thus provide communication coverage for a mobile geographic coverage area 110. In some examples, different geographic coverage areas 110 associated with different technologies may overlap, but different geographic coverage areas 110 may be supported by the same base station 105. In other examples, overlapping geographic coverage areas 110 associated with different technologies may be supported by different base stations 105. The wireless communication system 100 may include, for example, a heterogeneous network in which different types of base stations 105 provide coverage for various geographic coverage areas 110 using the same or different radio access technologies.

[0106] The wireless communication system 100 may support synchronous or asynchronous operations. For synchronous operations, the base stations 105 may have similar frame timings, and transmissions from different base stations 105 may be approximately aligned in time. For asynchronous operations, the base stations 105 may have different frame timings, and in some examples, transmissions from different base stations 105 may not be aligned in time. The techniques described herein may be used for synchronous or asynchronous operations.

[0107] Some UEs 115 (such as MTC or IoT devices) may be low-cost or low-complexity devices and may provide automated communication between machines (e.g., via machine-to-machine (M2M) communication). M2M communication or MTC may refer to data communication technologies that allow devices to communicate with each other or with the base station 105 without human intervention. In some examples, M2M communication or MTC may include communication from devices integrated with sensors or meters for measuring or capturing information and relaying that information to a central server or application, which may utilize the information or present the information to a person interacting with the program application. Some UEs 115 may be designed to collect information or implement automated behavior of machines or other devices. Application examples of MTC devices include smart metering, inventory monitoring, water level monitoring, equipment monitoring, medical monitoring, wildlife monitoring, weather and geological event monitoring, fleet management and tracking, remote security awareness, physical access control, and transaction-based business charging.

[0108] Some UEs 115 may be configured to operate in power-saving modes, such as half-duplex communication (e.g., a mode that supports one-way communication via transmission or reception, but not both transmission and reception simultaneously). In some examples, half-duplex communication may be performed at a reduced peak rate. Other power-saving techniques for UEs 115 include entering a power-saving deep sleep mode when not participating in active communication, operating on a limited bandwidth (e.g., according to narrowband communication), or a combination of these techniques. For example, some UEs 115 may be configured to operate using a narrowband protocol type associated with a defined portion or range within a carrier, within a guard band of the carrier, or external to the carrier (e.g., a set of subcarriers or resource blocks (RBs)).

[0109] The wireless communication system 100 can be configured to support ultra-reliable communication or low-latency communication or various combinations thereof. For example, the wireless communication system 100 can be configured to support ultra-reliable low-latency communication (URLLC) or mission-critical communication. The UE 115 can be designed to support ultra-reliability, low latency, or critical functions (e.g., mission-critical functions). Ultra-reliable communication can include private communication or group communication and can be supported by one or more mission-critical services (e.g., mission-critical push-to-talk (MCPTT), mission-critical video (MCVideo), or mission-critical data (MCData)). Support for mission-critical functions can include prioritization of services, and mission-critical services can be used for public safety or general commercial applications. The terms ultra-reliable, low-latency, mission-critical, and ultra-reliable low-latency can be used interchangeably herein.

[0110] In some examples, the UE 115 is also capable of directly communicating with other UEs 115 via a device-to-device (D2D) communication link 135 (e.g., using a peer-to-peer (P2P) or D2D protocol). One or more UEs 115 utilizing D2D communication can be within the geographical coverage area 110 of the base station 105. Other UEs 115 in such a group can be located outside the geographical coverage area 110 of the base station 105 or otherwise unable to receive transmissions from the base station 105. In some examples, a group of UEs 115 communicating via D2D communication can use a one-to-many (1:M) system in which each UE 115 transmits to every other UE 115 in the group. In some examples, the base station 105 facilitates the scheduling of resources for D2D communication. In other cases, D2D communication is performed between the UEs 115 without the participation of the base station 105.

[0111] The D2D communication link 135 can be an example of a communication channel (e.g., a sidelink communication channel) between vehicles (e.g., the UE 115). In some examples, vehicles can communicate using vehicle-to-everything (V2X) communication, vehicle-to-vehicle (V2V) communication, or some combination thereof. Vehicles can signal information related to traffic conditions, signal scheduling, weather, safety, emergencies, or any other information related to the V2X system. In some examples, vehicles in a V2X system can communicate with roadside infrastructure (e.g., roadside units) or communicate with the network via one or more network nodes (e.g., the base station 105) using vehicle-to-network (V2N) communication, or communicate with both.

[0112] The UE 115 can operate in the DRX mode. In some examples, the UE 115 can operate in the DRX mode at least partially based on a DRX configuration. The DRX configuration can define one or more DRX parameters, for example, the active duration of a DRX cycle, the inactive duration of a DRX cycle, the DRX cycle, the periodicity of the DRX cycle, the offset period associated with the active duration of the DRX cycle, the DRX inactivity timer, the DRX activity timer, the DRX retransmission timer, and so on. The DRX cycle can include the active duration of the DRX cycle, and the inactive duration of the DRX cycle can be defined in time units of time slots or milliseconds (ms).

[0113] In some examples, the DRX configuration can be per MAC entity. In some other examples, the DRX configuration can be per frequency range (FR). For example, a DRX configuration can be defined for FR1, which can refer to a frequency range between approximately 450 MHz and approximately 7.125 GHz, or for FR2, which can refer to a frequency range between approximately 24.25 GHz and approximately 52.6 GHz. The UE 115 can also be configured with a DRX configuration based on a preferred C-DRX configuration provided in UE assistance information (UAI), which includes a long DRX cycle, a short DRX cycle, a DRX inactivity timer, a short DRX cycle timer, and so on. In some examples, the UE 115 may not operate in the DRX mode (e.g., the DRX mode is disabled), and for power savings, the UE 115 can wake up based on a wake-up signal received from the base station 105.

[0114] The UE 115 can include a UE communication manager 101, which can provide high-reliability and low-latency wireless communication by supporting sidelink DRX operations for relay discovery, selection, and reselection as described herein. The UE communication manager 101 can be Figures 8 to 11 an example of an aspect of the UE communication manager described in. Similarly, the base station 105 can include a base station communication manager 102, which can provide sidelink DRX configuration as described herein. The base station communication manager 102 can be an example of an aspect of the base station communication manager as Figures 12 to 15 described.

[0115] The core network 130 can provide user authentication, access authorization, tracking, Internet Protocol (IP) connectivity, and other access, routing, or mobility functions. The core network 130 can be an evolved packet core (EPC) or a 5G core (5GC), which can include at least one control plane entity that manages access and mobility (e.g., a mobility management entity (MME), an access and mobility management function (AMF)), and at least one user plane entity that routes packets or interconnects to an external network (e.g., a serving gateway (S-GW), a packet data network (PDN) gateway (P-GW), or a user plane function (UPF)). The control plane entity can manage non-access stratum (NAS) functions, such as mobility, authentication, and bearer management for a UE 115 served by a base station 105 associated with the core network 130. User IP packets can be transmitted through the user plane entity, which can provide IP address allocation and other functions. The user plane entity can be connected to a network operator IP service 150. The operator IP service 150 can include access to the Internet, an intranet, an IP multimedia subsystem (IMS), or a packet-switched streaming service.

[0116] Some network devices (such as the base station 105) can include subcomponents (such as an access network entity 140), which can be an example of an access node controller (ANC). Each access network entity 140 can communicate with the UE 115 through one or more other access network transmission entities 145, which can be referred to as radio heads, intelligent radio heads, or transmit / receive points (TRPs). Each access network transmission entity 145 can include one or more antenna panels. In some configurations, the various functions of each access network entity 140 or base station 105 can be distributed across various network devices (e.g., radio heads and ANCs) or combined into a single network device (e.g., the base station 105).

[0117] The wireless communication system 100 can operate using one or more frequency bands in the range of 300 megahertz (MHz) to 300 gigahertz (GHz). The region from 300 MHz to 3 GHz is known as the ultra-high frequency (UHF) region or the decimeter band because the wavelength range is from approximately one decimeter to one meter in length. UHF waves can be blocked or redirected by buildings and environmental features, yet the waves can penetrate structures sufficiently to enable a macro cell to serve a UE 115 located indoors. Compared to transmissions at lower frequencies and longer wavelengths using the high frequency (HF) or very high frequency (VHF) portions of the spectrum below 300 MHz, UHF wave transmissions can be associated with smaller antennas and shorter ranges (e.g., less than 100 kilometers).

[0118] The wireless communication system 100 may also operate in the super high frequency (SHF) region using a frequency band from 3 GHz to 30 GHz (also known as the centimeter band), or in the extremely high frequency (EHF) region of the spectrum (e.g., from 30 GHz to 300 GHz), which is also known as the millimeter band. In some examples, the wireless communication system 100 may support millimeter wave (mmW) communication between the UE 115 and the base station 105, and the EHF antennas of the respective devices may be smaller and more closely spaced than UHF antennas. In some examples, this may facilitate the use of antenna arrays within the device. However, compared to SHF or UHF transmissions, the propagation of EHF transmissions may suffer greater atmospheric attenuation and shorter range. The techniques disclosed herein may be applied across transmissions using one or more different frequency regions, and the specified use of frequency bands across these frequency regions may vary by country or regulatory body.

[0119] The wireless communication system 100 may utilize both licensed and unlicensed radio frequency spectrum bands. For example, the wireless communication system 100 may employ licensed-assisted access (LAA) or LTE-unlicensed (LTE-U) radio access technologies or NR technologies in unlicensed frequency bands such as the 5 GHz industrial, scientific, and medical (ISM) band. When operating in an unlicensed radio frequency spectrum band, devices (such as the base station 105 and the UE 115) may employ carrier sensing for collision detection and avoidance. In some examples, operation in an unlicensed frequency band may be based on a carrier aggregation configuration in combination with component carriers operating in a licensed frequency band (e.g., LAA). Operations in the unlicensed spectrum may include downlink transmissions, uplink transmissions, P2P transmissions, or D2D transmissions, among other examples.

[0120] The base station 105 or the UE 115 may be equipped with multiple antennas, which may be used to employ techniques such as transmit diversity, receive diversity, multiple-input multiple-output (MIMO) communication, or beamforming. The antennas of the base station 105 or the UE 115 may be located within one or more antenna arrays or antenna panels, which may support MIMO operation or transmit or receive beamforming. For example, one or more base station antennas or antenna arrays may be co-located at an antenna assembly (such as an antenna tower). In some examples, the antennas or antenna arrays associated with the base station 105 may be located at different geographical locations. The base station 105 may have an antenna array having multiple rows and columns of antenna ports that the base station 105 may use to support beamforming for communication with the UE 115. Similarly, the UE 115 may have one or more antenna arrays that may support various MIMO or beamforming operations. Additionally or alternatively, the antenna panel may support radio frequency beamforming for signals transmitted via the antenna ports.

[0121] Base station 105 or UE 115 can use MIMO communication to utilize multipath signal propagation and increase spectral efficiency by transmitting or receiving multiple signals via different spatial layers. Such a technique may be referred to as spatial multiplexing. For example, multiple signals can be transmitted by a transmitting device via different antennas or different combinations of antennas. Similarly, multiple signals can be received by a receiving device via different antennas or different combinations of antennas. Each of the multiple signals can be referred to as a separate spatial stream and can carry bits associated with the same data stream (e.g., the same codeword) or different data streams (e.g., different codewords). Different spatial layers can be associated with different antenna ports for channel measurement and reporting. MIMO techniques include single-user MIMO (SU-MIMO) (where multiple spatial layers are transmitted to the same receiving device) and multi-user MIMO (MU-MIMO) (where multiple spatial layers are transmitted to multiple devices).

[0122] Beamforming (which may also be referred to as spatial filtering, directional transmission, or directional reception) is a signal processing technique that can be used at a transmitting device or a receiving device (e.g., base station 105, UE 115) to shape an antenna beam or manipulate an antenna beam (e.g., a transmit beam, a receive beam) along a spatial path between the transmitting device and the receiving device. Beamforming can be achieved by combining signals transmitted via the antenna elements of an antenna array such that some signals propagating in a particular direction relative to the antenna array experience constructive interference while other signals experience destructive interference. The adjustment of the signals transmitted via the antenna elements can include the transmitting device or the receiving device applying an amplitude offset, a phase offset, or both to the signals carried via the antenna elements associated with the device. The adjustment associated with each of these antenna elements can be defined by a set of beamforming weights associated with a particular direction (e.g., relative to the antenna array of the transmitting device or receiving device or relative to some other direction).

[0123] Base station 105 or UE 115 can use beam scanning techniques as part of beamforming operations. For example, base station 105 can use multiple antennas or antenna arrays (e.g., antenna panels) to perform beamforming operations for directional communication with UE 115. Base station 105 can transmit some signals (e.g., synchronization signals, reference signals, beam selection signals, or other control signals) multiple times in different directions. For example, base station 105 can transmit signals according to different sets of beamforming weights associated with different transmission directions. Transmissions in different beam directions can be used to identify (e.g., by a transmitting device such as base station 105 or by a receiving device such as UE 115) beam directions for later transmission or reception by base station 105.

[0124] Some signals (such as data signals associated with a particular receiving device) can be transmitted by the base station 105 in a single beam direction (e.g., the direction associated with a receiving device such as UE 115). In some examples, the beam direction associated with transmission along a single beam direction can be determined based on signals transmitted in one or more beam directions. For example, UE 115 can receive one or more signals transmitted by the base station 105 in different directions, and UE 115 can report an indication of the signal received by UE 115 with the highest signal quality or otherwise acceptable signal quality to the base station 105.

[0125] In some examples, multiple beam directions can be used to perform transmissions by a device (e.g., by the base station 105 or UE 115), and the device can use a combination of digital precoding or radio frequency beamforming to generate a combined beam for transmission (e.g., from the base station 105 to UE 115). UE 115 can report feedback indicating precoding weights for one or more beam directions, and the feedback can correspond to a configured number of beams across the system bandwidth or one or more subbands. The base station 105 can transmit reference signals (e.g., cell-specific reference signals (CRS), channel state information reference signals (CSI-RS)), which can be precoded or not precoded. UE 115 can provide feedback for beam selection, which can be a precoding matrix indicator (PMI) or codebook-based feedback (e.g., polyhedral codebook, linear combination codebook, port selection codebook). Although these techniques are described with reference to signals transmitted by the base station 105 in one or more directions, UE 115 can employ similar techniques for transmitting signals multiple times in different directions (e.g., for identifying beam directions for subsequent transmissions or receptions by UE 115), or for transmitting signals in a single direction (e.g., for transmitting data to a receiving device).

[0126] A receiving device (e.g., UE 115) may attempt various receive configurations (e.g., directional listening) when receiving various signals (such as synchronization signals, reference signals, beam selection signals, or other control signals) from a base station 105. For example, the receiving device may attempt multiple receive directions by: receiving via different antenna sub-arrays, processing the received signals according to different antenna sub-arrays, receiving according to different receive beamforming weight sets (e.g., different directional listening weight sets) applied to the signals received at a plurality of antenna element sets of the antenna array, or processing the received signals according to different receive beamforming weight sets applied to the signals received at a plurality of antenna elements of the antenna array, any of which may be referred to as "listening" according to different receive configurations or receive directions. In some examples, the receiving device may use a single receive configuration to receive along a single beam direction (e.g., when receiving a data signal). The single receive configuration may be aligned in a beam direction determined based on listening according to different receive configuration directions (e.g., a beam direction determined to have the highest signal strength, the highest signal-to-noise ratio (SNR), or another acceptable signal quality based on listening according to multiple beam directions).

[0127] The wireless communication system 100 may be a packet-based network operating according to a layered protocol stack. In the user plane, the communication at the packet data convergence protocol (PDCP) layer may be IP-based. The radio link control (RLC) layer may perform packet segmentation and reassembly for communication over logical channels. The medium access control (MAC) layer may perform priority handling and multiplex logical channels into transport channels. The MAC layer may also use error detection techniques, error correction techniques, or both to support retransmissions at the MAC layer to improve link efficiency. In the control plane, the radio resource control (RRC) protocol layer may provide the establishment, configuration, and maintenance of an RRC connection between the UE 115 and the base station 105 or the core network 130 that supports radio bearers for user plane data. At the physical layer, transport channels may be mapped to physical channels.

[0128] UE 115 and base station 105 can support retransmission of data to increase the likelihood of successfully receiving the data. Hybrid Automatic Repeat reQuest (HARQ) feedback is a technique for increasing the likelihood of correctly receiving data over communication link 125. HARQ can include a combination of error detection (e.g., using Cyclic Redundancy Check (CRC)), Forward Error Correction (FEC), and retransmission (e.g., Automatic Repeat reQuest (ARQ)). HARQ can improve throughput at the MAC layer under poor radio conditions (e.g., low signal-to-noise ratio conditions). In some examples, the device can support same-slot HARQ feedback, where the device can provide HARQ feedback for data received in a previous symbol in a particular slot during that slot. In other cases, the device can provide HARQ feedback in a subsequent slot or according to some other time interval.

[0129] Figure 2 FIG. illustrates an example of a wireless communication system 200 in accordance with one or more aspects of the present disclosure. The wireless communication system 200 can implement aspects of the wireless communication system 100. For example, the wireless communication system 200 can include base station 105-a, UE 115-a, UE 115-b, UE 115-c, and UE 115-d, which can be examples of the base station 105 and UE 115 described herein. The wireless communication system 200 can support multiple radio access technologies, including 4G systems such as LTE systems, LTE-A systems, or LTE-A Pro systems, and 5G systems that can be referred to as NR systems. The wireless communication system 200 can include features for improving power savings and, in some examples, can facilitate high-reliability and low-latency wireless communication as well as having other benefits.

[0130] The wireless communication system 200 can support sidelink communication between multiple UEs 115 via sidelink connections (also referred to as D2D connections). For example, UE 115-a and UE 115-b can perform sidelink communication via sidelink connection 205-a. UE 115-a can additionally or alternatively perform sidelink communication via sidelink connection 205-b with UE 115-c or via sidelink connection 205-c with UE 115-d. Similarly, UE 115-c and UE 115-d can perform sidelink communication via sidelink connection 205-d. The sidelink connections 205 can correspond to the PC5 interface, which can facilitate sidelink communication between at least two UEs 115 without involving base station 105-a. The PC5 interface can also be a one-to-many communication interface (e.g., can be designated for group communication).

[0131] In Figure 2In the example, UE 115 can communicate directly with base station 105-a or can communicate indirectly with base station 105-a. For example, UE 115-a can communicate directly with base station 105-a via cellular connection 210, and cellular connection 210 can correspond to the Uu interface. The Uu interface can refer to the air interface for downlink transmission, uplink transmission, or both. UE 115-b can communicate indirectly with base station 105-a via UE 115-a (also referred to as relay UE 115-a). For example, UE 115-b and base station 105-a may not be able to communicate directly because UE 115-b may be outside the coverage area of base station 105-a, and thus a relay UE is needed to relay the communication (e.g., control and / or data traffic) between UE 115-b and base station 105-a.

[0132] Relay UE 115-a can be configured by base station 105-a for relay services, and if configured, relay UE 115-a can be equipped with a configuration that controls the relay operation. To enable such network control, relay UE 115-a can indicate its relay capability to base station 105-a during the connection procedure (e.g., the attachment procedure). For example, relay UE 115-a can indicate a resource request for providing relay services, and base station 105-a can configure the requested resources for relay UE 115-a. Base station 105-a can control the relay service by configuring the conditions for relay UE 115-a to provide relay services to other UEs 115 in wireless communication system 200.

[0133] Base station 105-a can configure thresholds, such as a reference signal received power (RSRP) threshold, a received signal received quality (RSRQ) threshold, etc. Relay UE 115-a can provide relay services (e.g., act as a relay node in wireless communication system 200) based on the RSRP or RSRQ or both of the serving cell (e.g., base station 105-a that meets the RSRP threshold or RSRQ threshold or both). In other words, if the RSRP or RSRQ or both associated with cellular connection 210 (e.g., the Uu link) meet the RSRP threshold or RSRQ threshold or both, then relay UE 115-a can provide relay services. Otherwise, base station 105-a can prevent UE 115-a from acting as a relay node in wireless communication system 200 (e.g., providing relay services).

[0134] The wireless communication system 200 may also provide other conditions for supporting sidelink communication relay discovery and selection. For example, in the wireless communication system 200, the UE 115 may support sidelink communication relay discovery, selection, and reselection or combinations thereof when operating in an independent mode to enable sidelink-based UE-to-network and UE-to-UE relaying. The wireless communication system 200 may provide relay UE and remote UE authorization. In some examples, the relay UE 115-a may provide relay services (e.g., act as a relay node in the wireless communication system 200) based on meeting a quality of service (QoS) threshold associated with the data traffic between the base station 105-a and the relay UE 115-a. In the wireless communication system 200, the UE 115 may provide relay services based on service continuity, security of the relay connection (e.g., sidelink connection 205-a and / or cellular connection 210), or the impact on the user plane protocol stack and control plane procedures (e.g., connection management of the connection being relayed).

[0135] The UE 115 supporting sidelink communication may use the protocol stack described herein to provide sidelink communication. The remote UE 115-b may generate data traffic to be sent to the relay UE 115-a. This user data traffic may be packed into IP packets at the IP layer. Then the IP packets are passed down to the access stratum (AS) layer. The functions of the AS layer for sidelink communication are described below. The packet data convergence protocol (PDCP) layer of the AS layer may support header compression of received IP service data units to reduce the size of the IP packet headers of the IP packets. The PDCP layer may establish a sidelink radio bearer (SLRB) to carry the data traffic over the sidelink (e.g., sidelink connection 205-a between the remote UE 115-b and the relay UE 115-a). The RLC layer may be an unacknowledged mode (UM) radio link control (RLC) supported for sidelink communication. The support of UM RLC for sidelink communication may depend on delay-sensitive and fault-tolerant services.

[0136] The MAC layer of the AS layer can perform logical channel prioritization by considering the priority of each sidelink logical channel corresponding to the SLRB. The MAC header can include source ID and destination ID fields. The MAC layer at the relay UE 115-a can use the destination ID for packet filtering. Each MAC protocol data unit can have one new transmission and up to three retransmissions, enabling the relay UE 115-a to perform HARQ combining. The physical (PHY) layer of the AS layer can provide data transmission involving the transmission of physical control channels and physical data channels carrying sidelink control information (SCI). For each new transmission, the remote UE 115-b can send SCI indicating the layer 1 destination ID, modulation and coding scheme (MCS), and time-frequency location of the data traffic. Then, the remote UE 115-b can send the data traffic on the physical data channel immediately following the control channel.

[0137] UEs 115 outside the coverage area can be referred to as remote UEs 115 herein. In Figure 2 the example, UE 115-b can be referred to as remote UE 115-b. The remote UE 115-b can discover the relay UE 115-a based on discovery messages broadcast from the remote UE 115-b or discovery messages received from the relay UE 115-a. These messages can include certain information (such as synchronization information, service information, etc.) that can be used by the remote UE 115-b or the relay UE 115-a or both to establish a sidelink connection 205-a for relaying transmissions to and from the base station 105-a (e.g., for sending and receiving information related to the services provided by the base station 105-a). As described herein, the relay UE can be in the connected mode. That is, the relay UE can have a connection to the network (e.g., the base station 105-a). The remote UEs as described herein can operate in the connected mode, idle mode, inactive mode, or out-of-coverage mode or any combination thereof. Therefore, the sidelink DRX for the remote UE 115-b may have to be synchronized among all remote UEs 115 and relay UEs 115. The relay UE 115 can always be connected and thus synchronized with the base station 105-a.

[0138] The remote UE 115-b may not initially be connected to any relay UE in the wireless communication system 200 (e.g., no PC5 unicast link is established between the remote UE 115-b and the relay UE 115-a). The remote UE 115-b may identify the presence of at least one suitable relay UE 115 in its vicinity based on discovery messages to request relay services. To enable identification, the relay UE 115-a may announce its presence by periodically sending sidelink discovery messages, and / or the remote UE 115-b may announce sidelink discovery request messages, expecting a response from, for example, a nearby relay UE 115-a. Thus, for relay selection, the remote UE 115-b may not be connected to any relay UE. The remote UE 115-b may discover all relay UEs in the wireless communication system 200 having sidelink RSRP, RSRQ, QoS, etc. that meet a threshold. For relay reselection, the remote UE 115-b may be connected to at least one relay UE (e.g., the relay UE 115-a). When the sidelink RSRP, RSRQ, QoS, etc. do not meet the threshold, the remote UE 115-b may discover other relay UEs that meet the threshold. For example, the remote UE may discover multiple candidate relay UEs and select one relay UE having the highest sidelink RSRP, RSRQ, QoS, etc.

[0139] The remote UE 115-b seeking to discover a relay UE (e.g., the relay UE 115-a acting as a repeater) may consume a significant amount of power in some cases when monitoring discovery messages. The relay UE 115-a may also consume a significant amount of power when sending discovery messages. As a result, the battery life of the relay UE 115-a and the remote UE 115-b may be affected, which may also affect the reliability and latency of receiving service-related information at the remote UE 115-b. In other words, in the absence of sidelink DRX operation, the relay UE 115-a and the remote UE 115-b may keep their receivers and / or transmitters continuously active to monitor and receive relay discovery messages or send relay discovery request messages in the wireless communication system 200. Aspects of the described techniques relate to configuring the remote UE 115-b to operate in a power saving mode (also referred to as DRX mode) to reduce its power consumption when discovering and selecting a relay UE 115 as a repeater between the remote UE 115-b and the base station 105-a or other devices in the wireless communication system 200.

[0140] When in DRX mode, the remote UE 115-b can power on the appropriate circuitry for a period of time (e.g., the active duration of the DRX cycle) to monitor the wireless channel for discovery messages from other UEs 115. After this period elapses, the remote UE 115-b can power off for a period of time (e.g., the inactive duration of the DRX cycle). The DRX mode, including the periods for power on and power off, can be specific to when the remote UE 115-b monitors discovery messages. Once the remote UE 115-b detects a candidate relay UE (e.g., relay UE 115-a) based on the discovery message, the remote UE 115-b can select the candidate relay UE as a repeater based on the sidelink quality meeting a threshold as described herein or the candidate relay being able to provide the connection service requested by the remote UE 115-a.

[0141] The remote UE 115-b can evaluate the former condition by performing measurements on the discovery message received from the candidate relay UE 115-a, and it checks the latter condition by referring to a field (e.g., the relay service code) included in the discovery message provided by the candidate relay UE 115-a. The periods associated with the DRX mode can be configured and provided by the base station 105-a based on information provided by the remote UE 115-b. In some cases, the remote UE 115-b can belong to a group of UEs 115 that can share the sidelink configuration (e.g., sidelink DRX information) for the DRX mode. The group of UEs 115 can include the remote UE 115-b, UE 115-c, and UE 115-d. To avoid interference between the UEs 115 in the group, each UE 115 can have an offset period for when to power on and off as indicated in the sidelink DRX configuration described herein.

[0142] The sidelink DRX configuration can apply to broadcast communication, multicast communication, and unicast communication. The sidelink DRX configuration can define the active duration and the inactive duration of the DRX cycle. In some examples, the sidelink DRX configuration can provide a mechanism for aligning the sidelink DRX active durations between communicating UEs 115. In some other examples, the sidelink DRX configuration can provide a mechanism for aligning the sidelink DRX active duration with the Uu DRX active duration of the UEs 115 within the coverage area.

[0143] The remote UE 115-b can report its sidelink DRX preference to the base station 105-a when in the connected mode. For example, the remote 115-b can sometimes be within the coverage area of the base station 105-a and can report its sidelink DRX preference to the base station 105-a. The base station 105-a can configure the remote UE 115-b with a sidelink DRX configuration, which can be a UE-specific C-DRX configuration for both cellular reception (e.g., Uu reception) and relay discovery message monitoring. Alternatively, the remote UE 115-b can support a remote UE group common sidelink DRX configuration when in the idle mode, inactive mode, out-of-coverage mode, or any combination thereof. The remote UE group common sidelink DRX configuration can be broadcast in the system information block (SIB) and preconfigured messages (e.g., RRC preconfigured messages).

[0144] Once the remote UE 115-b detects a relay UE candidate (e.g., relay UE 115-a), it selects the relay UE 115-a based on meeting one or more criteria. For example, the remote UE 115-b can select the relay UE 115-a for relay service based on the sidelink quality of the sidelink connection 205-a meeting a threshold. Additionally or alternatively, the remote UE 115-b can select the relay UE 115-a for relay service based on the relay UE 115-a supporting the relay or connection service requested by the remote UE 115-b. The remote UE 115-b can evaluate one or both of these criteria. During relay discovery, the remote UE 115-b can obtain the UE identifier (ID) of the relay UE 115-a for sidelink transmission and reception of relay data traffic.

[0145] In some examples, if DRX is configured, the relay UE 115-a can send a sidelink broadcast channel (SL-BCH) for synchronizing the remote UE 115-b. Synchronization for sidelink communication can include the relay UE 115-a sending synchronization information to the remote UE 115-b via the sidelink connection 205-a, and then, the remote UE 115-b becomes synchronized. The synchronization information can include a physical synchronization signal (also referred to as a sidelink synchronization signal) and an RRC message (also referred to as a master information block (MIB) sidelink). For sidelink communication including a sidelink synchronization signal, the relay UE 115-a within the coverage area uses network synchronization related to uplink / downlink synchronization. If the remote UE 115-b outside the coverage area detects suitable synchronization information sent by the relay UE 115-a, the remote UE 115-b can use the detected synchronization information.

[0146] The remote UE 115-b can selectively (e.g., conditionally) enable or disable the sidelink DRX mode or sidelink DRX configuration. In some examples, the remote UE 115-b can enable the sidelink DRX by default if it is configured in the SIB or RRC pre-configuration message. In some other examples, the remote UE 115-b can enable the sidelink DRX by default at least based on the QoS of the outstanding data traffic at the remote UE 115-b. For example, if the minimum QoS of all outstanding data traffic is higher than the QoS threshold, the remote UE 115-b can enable the sidelink DRX. Otherwise, the remote UE 115-b can disable the sidelink DRX. Thus, when the remote UE 115-b has emergency data traffic, it is allowed to monitor all discovery messages to reduce the latency caused by relay selection. In other examples, the remote UE 115-b can enable the sidelink DRX based on the battery status (e.g., battery power, battery percentage) of the remote UE 115-b. Thus, if the battery of the remote UE 115-b is below the battery threshold, the remote UE 115-b can enable the sidelink DRX.

[0147] The relay UE 115-a can relay traffic between the sidelink connection 205-a (e.g., PC5 interface) and the cellular connection 210 (e.g., Uu interface) by performing traffic mapping. For example, the relay UE 115-a can map uplink / downlink bearers to sidelink bearers and vice versa, and this mapping can be used for proper packet routing and quality of service (QoS) handling. For the sidelink-to-uplink mapping that occurs when the relay UE 115-a receives traffic from the remote UE 115-b via the sidelink connection 205-a, the relay UE 115-a uses the uplink traffic flow template to select an uplink bearer to carry the received traffic over the uplink. For the downlink-to-sidelink mapping that occurs when the relay UE 115-a receives traffic from the base station 105-a via the cellular connection 210, it identifies whether the packet must be relayed by referring to the destination address of the packet. The relay UE 115-a then assigns a priority value (also known as per-packet ProSe priority (PPPP)) to the received packet to be relayed.

[0148] Priority allocation may be based on mapping information representing an association between a QoS class identifier (QCI) value of a downlink bearer and a priority value. The mapping information from QCI to priority may be provided by the base station 105-a to the relay UE 115-a. In some examples, the relay UE 115-a may allocate its discovery message transmission by applying random resource transmission pool selection (e.g., mode 2), or the base station 105-a may allocate scheduling within the DRX common activity duration (e.g., model). This may avoid relay UEs 115 with the same relay service code from being awakened simultaneously. The relay UE 115-a may thus send discovery messages more frequently according to its relay capabilities (e.g., supporting high QoS bearers with the base station 105-a and / or the remote UE 115-b).

[0149] The data service may be a unicast service or a multicast service. When the relay UE 115-a provides relay service for a unicast service, it establishes a one-to-one sidelink connection with the remote UE 115-a. The PC5 signaling protocol is introduced to provide direct connection management functions, such as direct link establishment / release, security parameter control, and IP address allocation. In addition, the protocol may support handling requests from the remote UE 115-b for multicast service relay. When establishing a sidelink connection, an IP address may be allocated for the remote UE 115-b for relay service. Once the relay UE 115-a establishes a sidelink connection 205-a with the remote UE 115-b, it reports information about the remote UE 115-b context to the base station 105-a, such as the EPS bearer ID for relay, the remote UE ID, and optionally, the IP address. This remote UE 115-a context is forwarded to the base station 105-a, which utilizes this information for service management, including mapping the relay service to the EPS bearer for relay.

[0150] Figure 3 An example of a process flow 300 in accordance with one or more aspects of the present disclosure is illustrated. The process flow 300 may implement aspects of the wireless communication systems 100 and 200 described with reference to Figure 1 and Figure 2 respectively. The process flow 300 may be based on the configuration of the base station 105-b or the UE 115-e, and implemented by the UE 115-e, and may facilitate power saving of the UE 115-e by supporting sidelink DRX operation. The process flow 300 may also be based on the configuration of the base station 105-b or the UE 115-e, and implemented by the UE 115-e to facilitate high-reliability and low-latency wireless communication by relaying wireless communication using sidelink communication, as well as other benefits.

[0151] Base station 105-b and UE 115-e may be examples of base station 105 and UE 115, as referenced Figure 1 and Figure 2 described. In the following description of process flow 300, operations between base station 105-b and UE 115-e may be sent in an order different from the example order shown, or operations performed by base station 105-b and UE 115-e may be performed in a different order or at different times. Some operations of process flow 300 may also be omitted, and other operations may be added to process flow 300.

[0152] In Figure 3 the example of, UE 115-e may operate in a connected mode. That is, UE 115-b may initially have a direct connection with base station 105-b (e.g., via the Uu interface). In Figure 3 the example of, UE 115-e may initially not be connected to a relay node (e.g., a relay UE) in the wireless communication system. However, later UE 115-e may be outside the coverage area of base station 105-b and may continue to communicate wirelessly with base station 105-b using a relay UE described herein. Aspects of process flow 300 involve configuring UE 115-e to operate in a power saving mode (also referred to as a sidelink DRX mode or C-DRX mode) to reduce its power consumption while monitoring the wireless communication system to discover and select a relay UE to be used as a relay between UE 115-e and base station 105-b.

[0153] At 305, UE 115-e may send sidelink DRX information to base station 105-b, for example, via the Uu interface. UE 115-e may send the sidelink DRX information in UE assistance information (UAI). The sidelink DRX information may indicate DRX preferences, which may include a DRX cycle, an active duration of the DRX cycle, an offset period before the active duration of the DRX cycle, a DRX inactivity timer, a DRX retransmission timer, etc. UE 115-b may thereby report its preference for sidelink DRX operation to base station 105-b via the sidelink DRX information. UE 115-e may determine the DRX preference based at least in part on the relay service or QoS requirements or both of the outstanding data traffic at UE 115-e.

[0154] At 310, the base station 105-b can determine the sidelink DRX configuration, for example, based on the sidelink DRX information received from the UE 115-e. The sidelink DRX configuration can define a DRX pattern including an active duration of the DRX cycle and an inactive duration of the DRX cycle. The base station 105-b can configure a UE-specific DRX pattern for the UE 115-e via a Uu RRC message. That is, the base station 105-b can configure a single DRX pattern for the UE 115-b for both cellular communication (e.g., Uu reception / transmission) and relay discovery monitoring and selection (e.g., via the PC5 interface). In some examples, the base station 105-b can determine or adjust the sidelink DRX configuration via an RRC message to modify the sidelink DRX configuration. Since the base station 105-a may know the discovery resource pool configuration of the UE 115-e, it can modify or configure the sidelink DRX configuration (e.g., C-DRX) to account for the overlap with the discovery resource pool configuration during the DRX cycle (e.g., C-DRX ON period).

[0155] At 315, the base station 105-b can send an RRC reconfiguration message including the sidelink DRX configuration to the UE 115-e. At 320, the UE 115-e can send an RRC reconfiguration complete message to the base station 105-e. Additionally or alternatively, in some examples, the base station 105-b can determine multiple DRX patterns (e.g., multiple C-DRX patterns) for the UE 115-e. One DRX pattern can be used for Uu reception, while another DRX pattern can be used for relay discovery monitoring. The base station 105-b can send the multiple DRX patterns in a single RRC reconfiguration message or separate RRC reconfiguration messages.

[0156] Figure 4 An example of a timeline 400 in accordance with one or more aspects of the present disclosure is illustrated. The timeline 400 can implement aspects of the wireless communication systems 100 and 200 described with reference to Figure 1 and Figure 2 respectively. The timeline 400 can be based on the configuration of the base station 105 or the UE 115 and be implemented by the UE 115 to reduce the power consumption of the UE 115 by supporting sidelink DRX operation. The timeline 400 can also be based on the configuration of the base station 105 or the UE 115 and be implemented by the UE 115 to facilitate high-reliability and low-latency wireless communication in the wireless communication system, as well as other benefits.

[0157] Referring to timeline 400, relay UE 115-f or remote UE 115-g, or both as described herein, may operate according to a sidelink DRX configuration. The sidelink DRX configuration may define a DRX cycle 405, which may include an active DRX duration 410 and an inactive DRX duration 415. During the active DRX duration 410, relay UE 115-f may broadcast one or more discovery messages 420 over a sidelink channel. Remote UE 115-g may monitor a discovery resource pool 425 for one or more broadcast discovery messages 420 during the active DRX duration 410.

[0158] The resource pool may be a reception resource pool or a transmission resource pool, or a combination thereof. These may be signaled by base station 105 for in-coverage scenarios or preconfigured for out-of-coverage scenarios. In Figure 4 the example of, discovery resource pool 425 may be a reception resource pool. Discovery resource pool 425 may be a set of time and frequency resources allocated to remote UE 115-g for sidelink operation, more specifically for monitoring discovery messages 420.

[0159] Relay UE 115-f may also support cellular communication (e.g., via the Uu interface) during the inactive DRX duration 415 of the DRX cycle 405. For example, relay UE 115-f may support cellular (Uu interface) transmission and reception (e.g., uplink / downlink messages 430) to and from base station 105 via the Uu interface. As Figure 4 illustrated, remote UE 115-g may not perform any operations (e.g., monitor a channel for discovery messages, etc.) during the inactive DRX duration 415 of the DRX cycle 405. Remote UE 115-g may thus experience additional power savings for relay discovery monitoring by disabling monitoring for one or more discovery messages 420 during the inactive DRX duration 415 of the DRX cycle 405.

[0160] Figure 5 An example of a timeline 500 in accordance with one or more aspects of the present disclosure is illustrated. Timeline 500 may implement aspects of the wireless communication systems 100 and 200 respectively described in Figure 1 and Figure 2 . Timeline 500 may be based on the configuration of base station 105 or UE 115 and implemented by UE 115 to reduce the power consumption of UE 115 by supporting sidelink DRX operation. Timeline 500 may also be based on the configuration of base station 105 or UE 115 and implemented by UE 115 to facilitate high-reliability and low-latency wireless communication in a wireless communication system, as well as other benefits.

[0161] Referring to timeline 500, one or more remote UEs 115 may receive a common sidelink DRX configuration in a system information message (e.g., SIB) or an RRC message (e.g., RRC reconfiguration message). For example, the base station 105 may broadcast a system information message (e.g., SIB) or an RRC message (e.g., RRC reconfiguration message) to one or more remote UEs 115. One or more remote UEs 115 may not have a PC5 unicast link with an established relay UE, and one or more remote UEs 115 may operate in an idle mode, an inactive mode, or an out-of-coverage mode or a combination thereof. Thus, one or more remote UEs 115 may be configured with a common sidelink DRX configuration to save power when monitoring discovery messages from candidate relay UEs.

[0162] For example, remote UEs 115-h and 115-i as described herein may operate according to a common sidelink DRX configuration. Remote UEs 115-h and 115-i may be grouped into the same UE group based at least in part on a path loss parameter of each of remote UEs 115-h and 115-i to the base station 105 or the QoS of the outstanding data traffic of each of remote UEs 115-h and 115-i or both. The common sidelink DRX configuration may define a DRX cycle 505, which may include an active DRX duration 510 and an inactive DRX duration 515. The DRX cycle 505 may be a common DRX cycle for remote UEs 115-h and 115-i. Thus, the active DRX duration 510 may be a common active DRX duration for remote UEs 115-h and 115-i. Similarly, the inactive DRX duration 515 may be a common inactive DRX duration for remote UEs 115-h and 115-i.

[0163] Alternatively, as described herein, the remote UE 115-j may operate according to a common sidelink DRX configuration different from the common sidelink DRX configuration associated with the remote UE 115-h and the remote UE 115-i. The common sidelink DRX configuration may define a DRX cycle 520, which may include an active DRX duration 525 and an inactive DRX duration 530. To avoid interference between different groups of UEs 115, the common sidelink DRX configuration may include different group-common DRX cycles, different group-common active DRX durations, different group-common DRX offset periods, different monitoring durations (e.g., the duration length may be group-common but without an offset), and so on. That is, the remote UEs 115 belonging to different UE groups may perform operations (e.g., monitor the sidelink channel for discovery messages) based on different sidelink DRX configurations.

[0164] In Figure 5 the example, the active DRX duration 510 associated with the DRX cycle 505 may start at t n and the active DRX duration 525 associated with the DRX cycle 520 may start at t n . However, the active DRX duration 510 may end at t n+2 while the active DRX duration 525 ends at t n+1 . The inactive DRX duration 515 associated with the DRX cycle 505 may start at t n+2 and the inactive DRX duration 530 associated with the DRX cycle 520 may start at t n+1 . In Figure 5 the example, both the inactive DRX duration 515 associated with the DRX cycle 505 and the inactive DRX duration 530 associated with the DRX cycle 520 may end at t n+3 . The active DRX duration and the inactive DRX duration may thus have different lengths for different sidelink DRX configurations to avoid interference and to provide the remote UE 115 with an opportunity to monitor discovery messages. Additionally, the remote UE 115 may experience additional power savings for relay discovery monitoring by disabling the monitoring for discovery messages during the inactive DRX duration of the DRX cycle.

[0165] Figure 6 illustrates an example of a timeline 600 in accordance with one or more aspects of the present disclosure. The timeline 600 may implement references Figure 1 and Figure 2Aspects of the described wireless communication systems 100 and 200. Timeline 600 may be based on the configuration of base station 105 or UE 115 and implemented by UE 115 to reduce the power consumption of UE 115 by supporting sidelink DRX operation. Timeline 600 may also be based on the configuration of base station 105 or UE 115 and implemented by UE 115 to facilitate high-reliability and low-latency wireless communication in the wireless communication system, as well as other benefits.

[0166] Referring to timeline 600, one or more remote UEs 115 may receive a common sidelink DRX configuration in a system information message (e.g., SIB) or an RRC message (e.g., RRC reconfiguration message). For example, base station 105 may broadcast a system information message (e.g., SIB) or an RRC message (e.g., RRC reconfiguration message) to one or more remote UEs 115. Remote UEs 115-l and remote UEs 115-m as described herein may operate according to the common sidelink DRX configuration. As described herein, remote UEs 115-1 and remote UEs 115-m may be grouped into the same UE group based at least in part on one or more parameters (e.g., path loss, QoS of outstanding data traffic, etc.). In some examples, as described herein, the common active DRX duration may be configured to overlap with a discovery resource pool that may be configured for one or both of a first model discovery process (e.g., advertisement message) or a second model discovery process (e.g., request and response message).

[0167] The common sidelink DRX configuration may define a DRX cycle 605, which may include an active DRX duration 610 and an inactive DRX duration 615. The DRX cycle 605 may be a common DRX cycle for remote UEs 115-l and remote UEs 115-m. Thus, the active DRX duration 610 may be a common active DRX duration for remote UEs 115-l and remote UEs 115-m. Similarly, the inactive DRX duration 615 may be a common inactive DRX duration for remote UEs 115-l and remote UEs 115-m. To avoid interference between remote UE 115-1 and remote UEs 115-m belonging to the same group of UEs, the common sidelink DRX configuration may define a monitoring duration for each of remote UEs 115-l and remote UEs 115-m, and an offset duration for one or both of remote UEs 115-1 and remote UEs 115-m. That is, to avoid waking up simultaneously, different UEs 115-l, UEs 115-m may have UE-specific DRX monitoring offsets via a random offset or a mapping taking the remote UE source L2 ID as an input (e.g., similar to paging PO calculation).

[0168] The remote UE 115-1 can monitor the sidelink channel for one or more discovery messages 620 from the relay UE 115-k during a monitoring duration 630 of the active DRX duration 610 associated with the DRX cycle 605. The monitoring duration 630 can start at t n Similarly, the remote UE 115-m can monitor the sidelink channel for one or more discovery messages 620 from the relay UE 115-k during a monitoring duration 635 of the active DRX duration 610 associated with the DRX cycle 605. The monitoring duration 630 can start at t n+1 and end at t n+2 , for example when the inactive DRX duration 615 starts. Thus, each of the remote UE 115-1 and the remote UE 115-m can have a portion of the active DRX duration allocated for monitoring discovery messages from the relay UE 115-k. Additionally, the monitoring duration 635 can start after an offset duration 640 spanning from t n to t n+1 . Accordingly, the remote UE 115 can perform operations (e.g., monitor the sidelink channel for discovery messages) based on different monitoring durations indicated in the sidelink DRX configuration.

[0169] The remote UE 115-l can be configured to stop monitoring all receive resource pools outside the monitoring duration 630. Similarly, the remote UE 115-m can be configured to stop monitoring all receive resource pools outside the monitoring duration 635. If separate discovery and common pools are configured for the remote UE 115, the remote UE 115-1 can be configured to stop monitoring all receive resource discovery pools. Similarly, if separate discovery and common pools are configured for the remote UE 115, the remote UE 115-m can be configured to stop monitoring all receive resource discovery pools. This can apply to the case where the UE 115 has another PC5 unicast link setup for normal PC5 operation. One power consumption difference: discovery is multicast and broadcast and takes the maximum transmit power, while common messages can use open-loop and closed-loop power control. Discovery messages can be periodic and the UE 115 can adapt to the DRX mode, while common messages can be bursty. Based on the indication in the SIB or RRC pre-configuration message, the remote UE 115-1, 115-m can determine to stop monitoring all receive resource pools, including the receive resource discovery pools outside the monitoring durations 630, 635.

[0170] Relay UE 115-k may also support cellular communication (e.g., via the Uu interface) during the inactive DRX duration 615 of the DRX cycle 605. For example, relay UE 115-k may support cellular (Uu interface) transmission and reception (e.g., uplink / downlink messages 625) to and from base station 105 via the Uu interface. As Figure 6 illustrated, remote UEs 115-l, 115-m may not perform any operations (e.g., channel monitoring for discovery messages, etc.) during the inactive DRX duration 615 of the DRX cycle 605. Remote UEs 115-l, 115-m may thus experience additional power savings for relay discovery monitoring by disabling monitoring for one or more discovery messages 620 during the inactive DRX duration 615 of the DRX cycle 605. The inactive DRX duration 615 of the DRX cycle 605 may also provide power savings for relay UE 115-k by avoiding sending discovery messages and performing other radio operations (e.g., uplink / downlink transmission / reception) during the inactive DRX duration 615. That is, relay UE 115-k may perform discontinuous transmission (i.e., turn off its transmitter) because it knows the DRX cycle 605 of remote UEs 115-l, 115-m. In some examples, relay UE 115-k may send some relay discovery messages for remote UE 115 with pending emergency data traffic during the DRX common inactive duration. Relay UE 115 may alternatively perform Uu transmission / reception during the DRX common inactive duration.

[0171] Figure 7 An example of a timeline 700 in accordance with one or more aspects of the present disclosure is illustrated. Timeline 700 may implement aspects of the wireless communication systems 100 and 200 described with reference to Figure 1 and Figure 2 respectively. Timeline 700 may be based on the configuration of base station 105 or UE 115 and implemented by UE 115 to reduce the power consumption of UE 115 by supporting sidelink DRX operation. Timeline 700 may also be based on the configuration of base station 105 or UE 115 and implemented by UE 115 to facilitate high-reliability and low-latency wireless communication in the wireless communication system, as well as other benefits. In Figure 7 the example, a single UE 115 group may include one or more relay UEs 115 and remote UEs. The UE group may share the same active DRX duration of a DRX cycle. The monitoring window of the remote UE may be the same as the DRX common on duration.

[0172] Referring to timeline 700, relay UE 115-n, relay UE 115-o, relay UE 115-p, or remote UE 115-q as described herein, or any combination thereof, may operate according to a sidelink DRX configuration. The sidelink DRX configuration may define a DRX cycle 705, which may include one or more active DRX durations 710 and an inactive DRX duration 715. In some examples, during the active DRX duration 710, relay UE 115-n may broadcast one or more discovery messages 720 via a sidelink channel. In some other examples, during the active DRX duration 710, relay UE 115-o may broadcast one or more discovery messages 725 via a sidelink channel. In other examples, relay UE 115-p may broadcast one or more discovery messages 730 via a sidelink channel. One or more of relay UE 115-n, relay UE I15-o, and relay UE 115-p may allocate discovery message transmissions by applying random resource transmission pool selection (e.g., mode 2), or the base station 105 may allocate scheduling (e.g., model) for the discovery message transmissions of relay UE 115. This may avoid mutual interference caused by relay UEs 115 with the same relay service code being awakened simultaneously.

[0173] Remote UE 115-q may monitor a discovery resource pool for one or more broadcast discovery messages 720, 725, and 730 during the active DRX duration 410. The resource pool may be a receive resource pool, a transmit resource pool, or a combination thereof. These may be signaled by the base station 105 for in-coverage scenarios or pre-configured for out-of-coverage scenarios. In Figure 7 an example, remote UE 115-q may enable resource pool monitoring 740 during the active DRX duration 710 and disable resource pool monitoring 745 during the inactive DRX duration 715. The discovery resource pool 425 may be a receive resource pool. As Figure 7 illustrated, the discovery resource pool may be a set of time and frequency resources allocated to remote UE 115-q for sidelink operation, more specifically for monitoring one or more sidelink channels for one or more discovery messages 720, 725, and 730.

[0174] As Figure 7As described, the remote UE 115-q may not perform any operations (e.g., channel monitoring for discovery messages, etc.) during the inactive DRX duration 715 of the DRX cycle 705. The remote UE 115-q can thus experience additional power savings for relay discovery monitoring by disabling monitoring for one or more discovery messages 720, 725, and 730 during the inactive DRX duration 715 of the DRX cycle 705. One or more of the relay UEs 115-n, 115-o, and 115-p can also support cellular communication (e.g., via the Uu interface) during the inactive DRX duration 715 of the DRX cycle 705. For example, the relay UE 115-p can support cellular (Uu interface) transmission and reception (e.g., uplink / downlink messages 735) to and from the base station 105 via the Uu interface. One or more of the relay UEs 115-n, 115-o, and 115-p can also experience power savings by avoiding sending discovery messages and performing other wireless operations (e.g., uplink / downlink transmission / reception) during the inactive DRX duration 715.

[0175] Figure 8 FIG. 800 is a block diagram of a device 805 in accordance with one or more aspects of the present disclosure. The device 805 may be an example of an aspect of the UE 115 as described herein. The device 805 may include: a receiver 810, a UE communication manager 815, and a transmitter 820. The device 805 may also include a processor. Each of these components may communicate with one another (e.g., via one or more buses).

[0176] The receiver 810 may receive information such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information related to DRX for sidelink communication in a wireless communication system). The information may be passed to other components of the device 805. The receiver 810 may be an example of aspects of the transceiver 1120 described with reference to Figure 11 FIG. The receiver 810 may use a single antenna or an antenna array.

[0177] The UE communication manager 815 may send sidelink DRX information to a base station when operating in a connected mode, receive a message including a sidelink DRX configuration from the base station based on the sidelink DRX information, and operate according to the sidelink DRX configuration.

[0178] The UE communication manager 815 may also receive, when operating in an out-of-coverage mode, an idle mode, or an inactive mode, a message including a group sidelink DRX configuration associated with a group of UEs; determine, based on the group sidelink DRX configuration, a time period during which discontinuous monitoring of the sidelink channel can be performed; and monitor the sidelink channel during the time period.

[0179] The UE communication manager 815 may also determine a DRX cycle based on the sidelink DRX configuration, the DRX cycle including an active duration and an inactive duration; receive a discovery request message from a second UE during the active duration of the DRX cycle; and send a discovery response message to the second UE during the active duration of the DRX cycle. The UE communication manager 815 may be an example of an aspect of the UE communication manager 1110 described herein.

[0180] The UE communication manager 815 or its sub-components may be implemented in hardware, code executed by a processor (e.g., software or firmware), or any combination thereof. If implemented in code executed by a processor, the functions of the UE communication manager 815 or its sub-components may be performed by a general-purpose processor, a DSP, an application-specific integrated circuit (ASIC), an FPGA, or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described in this disclosure.

[0181] The UE communication manager 815 or its sub-components may physically be located in various positions, including distributed such that portions of the functionality are implemented by one or more physical components in different physical locations. In some examples, in accordance with various aspects of this disclosure, the UE communication manager 815 or its sub-components may be separate and distinct components. In some examples, in accordance with various aspects of this disclosure, the UE communication manager 815 or its sub-components may be combined with one or more other hardware components, including but not limited to input / output (I / O) components, transceivers, network servers, another computing device, one or more other components described in this disclosure, or combinations thereof.

[0182] The transmitter 820 may send signals generated by other components of the device 805. In some examples, the transmitter 820 may be co-located with the receiver 810 in a transceiver module. For example, the transmitter 820 may be an example of aspects of the transceiver 1120 described with reference to Figure 11 The transmitter 820 may use a single antenna or an antenna array.

[0183] Figure 9Block diagram 900 of device 905 is shown in accordance with one or more aspects of the present disclosure. Device 905 may be an example of an aspect of device 805 or UE 115 as described herein. Device 905 may include: a receiver 910, a UE communication manager 915, and a transmitter 940. Device 905 may also include a processor. Each of these components may communicate with each other (e.g., via one or more buses).

[0184] The receiver 910 may receive information such as packets, user data, or control information associated with respective information channels (e.g., control channels, data channels, and information related to DRX for sidelink communication in a wireless communication system). The information may be passed to other components of device 905. The receiver 910 may be an example of aspects of the transceiver 1120 described with reference Figure 11 to. The receiver 910 may use a single antenna or an antenna array.

[0185] The UE communication manager 915 may be an example of an aspect of the UE communication manager 815 described herein. The UE communication manager 915 may include a sidelink information component 920, a sidelink configuration component 925, a mode component 930, and a discovery component 935. The UE communication manager 915 may be an example of an aspect of the UE communication manager 1110 described herein.

[0186] The sidelink information component 920 may send sidelink DRX information to a base station when operating in a connected mode. The sidelink configuration component 925 may receive a message including a sidelink DRX configuration from the base station based on the sidelink DRX information. The mode component 930 may operate according to the sidelink DRX configuration.

[0187] The sidelink configuration component 925 may receive a message including a group sidelink DRX configuration associated with a group of UEs when operating in an out-of-coverage mode, an idle mode, or an inactive mode. The mode component 930 may determine a period during which discontinuous monitoring of the sidelink channel is enabled based on the group sidelink DRX configuration and monitor the sidelink channel during that period.

[0188] The sidelink configuration component 925 may determine a DRX cycle based on the sidelink DRX configuration, where the DRX cycle includes an active duration and an inactive duration. The discovery component 935 may receive a discovery request message from a second UE during the active duration of the DRX cycle and send a discovery response message to the second UE during the active duration of the DRX cycle.

[0189] Transmitter 940 may transmit signals generated by other components of device 905. In some examples, transmitter 940 may be co-located with receiver 910 in a transceiver module. For example, transmitter 940 may be an example of aspects of transceiver 1120 described with reference to Figure 11 Transmitter 940 may use a single antenna or an antenna array.

[0190] Figure 10 FIG. 1000 is a block diagram of UE communication manager 1005 in accordance with one or more aspects of the present disclosure. UE communication manager 1005 may be an example of aspects of UE communication manager 815, UE communication manager 915, or UE communication manager 1110 described herein. UE communication manager 1005 may include sidelink information component 1010, sidelink configuration component 1015, mode component 1020, discovery component 1025, relay component 1030, network component 1035, message component 1040, resource pool component 1045, synchronization component 1050, and sidelink component 1055. Each of these modules may communicate directly or indirectly with each other (e.g., via one or more buses).

[0191] Sidelink information component 1010 may send sidelink DRX information to a base station when operating in a connected mode. In some examples, sidelink information component 1010 may include the sidelink DRX information in a UAI. In some examples, sidelink information component 1010 may send a UAI including the sidelink DRX information to a base station when operating in a connected mode, where reception of a message including a sidelink DRX configuration is based on the UAI.

[0192] Sidelink configuration component 1015 may receive a message including a sidelink DRX configuration from a base station based on the sidelink DRX information. In some examples, sidelink configuration component 1015 may receive a message including a group sidelink DRX configuration associated with a group of UEs when operating in an out-of-coverage mode, an idle mode, or an inactive mode. In some examples, sidelink configuration component 1015 may determine a DRX cycle based on the sidelink DRX configuration, the DRX cycle including an active duration and an inactive duration. In some examples, sidelink configuration component 1015 may receive a SIB or RRC reconfiguration message including a group sidelink DRX configuration. In some examples, sidelink configuration component 1015 may enable discontinuous monitoring of a sidelink channel based on the SIB or RRC reconfiguration message.

[0193] In some examples, the sidelink configuration component 1015 may disable the DRX mode based on meeting a QoS threshold associated with the outstanding data traffic. In some cases, the sidelink DRX configuration includes a connected mode DRX configuration. In some cases, the sidelink DRX configuration includes a sidelink DRX preference associated with a discovery process including a first model discovery process or a second model discovery process. In some cases, the sidelink DRX configuration includes a sidelink DRX preference associated with receiving a downlink signal from a base station or transmitting an uplink signal to a base station or both. In some cases, the UE includes a remote UE and the second UE includes a relay UE between the remote UE and the base station. In some cases, the group sidelink DRX configuration includes a DRX cycle common to the group of UEs.

[0194] In some cases, the sidelink DRX configuration includes an active duration of the DRX cycle common to the group of UEs. In some cases, the sidelink DRX configuration includes a group offset duration between the start of the DRX cycle and the active duration of the DRX cycle, where the group offset duration is common to the group of UEs. In some cases, the UEs are grouped into the group of UEs based on a path loss parameter. In some cases, the UEs are grouped into the group of UEs based on the QoS associated with the data traffic of the UEs. In some cases, the sidelink DRX configuration is based on a discovery resource pool corresponding to time and frequency resources for receiving a discovery request message or transmitting a discovery response message or both.

[0195] The mode component 1020 may operate according to the sidelink DRX configuration. In some examples, the mode component 1020 may determine a time period for enabling discontinuous monitoring of the sidelink channel based on the group sidelink DRX configuration. In some examples, the mode component 1020 may monitor the sidelink channel during the time period. In some examples, the mode component 1020 may determine a single connected mode DRX cycle for sidelink communication or cellular communication or both based on the sidelink DRX configuration. In some examples, the mode component 1020 may be based on the single connected mode DRX cycle when operating according to the sidelink DRX configuration. In some examples, the DRX cycle is determined based on a relay service associated with the second UE or the QoS associated with the data traffic of the UE or both, where the sidelink DRX information includes an indication of the DRX cycle.

[0196] In some examples, the mode component 1020 may determine a value of an active timer associated with a DRX cycle based on a relay service associated with a second UE or a QoS associated with the UE's data traffic or both, where the sidelink DRX information includes an indication of the value of the active timer associated with the DRX cycle. In some examples, the mode component 1020 may determine a value of an inactive timer associated with a DRX cycle based on a relay service associated with a second UE or a QoS associated with the UE's data traffic or both, where the sidelink DRX information includes an indication of the value of the inactive timer associated with the DRX cycle.

[0197] In some examples, based on a relay service associated with a second UE or a QoS associated with the UE's data traffic or both, an offset between a start of a DRX cycle and a start of an active duration of the DRX cycle is determined, where the sidelink DRX information includes an indication of the offset. In some examples, the mode component 1020 may determine a first sidelink DRX mode associated with a sidelink DRX configuration for monitoring a sidelink channel to receive a discovery signal based on the sidelink DRX configuration. In some examples, the mode component 1020 may determine a second sidelink DRX mode associated with a sidelink DRX configuration for receiving a downlink signal from a base station or transmitting an uplink signal to a base station or both based on the sidelink DRX configuration, where the first sidelink DRX mode is different from the second sidelink DRX mode.

[0198] In some examples, a UE-specific offset duration associated with an active duration of a DRX cycle is determined based on the sidelink DRX configuration, where monitoring the sidelink channel includes. In some examples, the mode component 1020 may enable the DRX mode based on the message. In some examples, the mode component 1020 may enable the DRX mode based on a QoS associated with pending data traffic meeting a QoS threshold. In some examples, the mode component 1020 may enable the DRX mode based on a power level of the UE meeting a power level threshold. In some cases, the sidelink DRX configuration includes a first indication of a first sidelink DRX mode or a second indication of a second sidelink DRX mode, or both. In some cases, the time period is common for the group of UEs. In some cases, the UE-specific offset duration is based on an L2 identifier associated with the UE.

[0199] The discovery component 1025 can receive a discovery request message from a second UE during the active duration of a DRX cycle. In some examples, the discovery component 1025 can send a discovery response message to the second UE during the active duration of a DRX cycle. In some examples, the discovery component 1025 can monitor a sidelink channel based on a sidelink DRX configuration to receive a discovery signal from the second UE during the active duration of a DRX cycle. In some examples, the discovery component 1025 can receive a discovery signal from the second UE based on this monitoring. In some examples, the discovery component 1025 can broadcast a discovery request message based on a sidelink DRX configuration during the active duration of a DRX cycle.

[0200] In some examples, the discovery component 1025 can monitor a sidelink channel to receive a discovery response message from the second UE during the active duration of a DRX cycle. In some examples, the discovery component 1025 can receive a discovery response message from the second UE based on this monitoring, where the discovery signal includes a discovery response message. In some examples, the discovery component 1025 can determine a sidelink DRX mode for monitoring a sidelink channel to receive a discovery signal from the second UE based on a sidelink DRX configuration, where the sidelink DRX mode includes a DRX cycle, and the DRX cycle includes an active duration and an inactive duration. In some examples, the discovery component 1025 can broadcast a discovery request message during the inactive duration of a DRX cycle associated with a group of UEs based on the data traffic conditions of the UEs, where the inactive duration is common to the group of UEs, and where the inactive duration and the DRX cycle are common to the group of UEs. In some cases, the sidelink DRX configuration is based on a discovery resource pool corresponding to time and frequency resources associated with monitoring a sidelink channel to receive a discovery signal from the second UE.

[0201] The relay component 1030 can select a second UE for relay communication between the UE and a base station or between the UE and a third UE or both based on a discovery signal, where the relay communication corresponds to an L2 forwarding function or an L3 forwarding function. In some examples, the relay component 1030 can receive a synchronization signal from the second UE on a sidelink broadcast channel. In some examples, the relay component 1030 can synchronize with the second UE based on the synchronization signal.

[0202] The network component 1035 may receive downlink signals from the base station using the cellular link based on the sidelink DRX configuration. In some examples, the network component 1035 may send uplink signals to the base station using the cellular link based on the sidelink DRX configuration. In some examples, the network component 1035 may determine a sidelink DRX mode for receiving downlink signals or sending uplink signals or both based on the sidelink DRX configuration, where the sidelink DRX mode includes a DRX cycle, and the DRX cycle includes an active duration and an inactive duration, and receiving downlink signals or sending uplink signals or both are based on the sidelink DRX mode. In some examples, the network component 1035 may receive downlink signals from the base station during the inactive duration of the DRX cycle associated with the group of UEs. In some examples, the network component 1035 may send uplink signals to the base station during the inactive duration of the DRX cycle associated with the group of UEs, where the inactive duration and the DRX cycle are common to the group of UEs.

[0203] The message component 1040 may receive an RRC reconfiguration message from the base station that includes the sidelink DRX configuration. In some examples, the message component 1040 may send an RRC reconfiguration complete message to the base station based on the RRC reconfiguration message, where operating according to the sidelink DRX configuration is based on the RRC reconfiguration complete message.

[0204] The resource pool component 1045 may avoid monitoring one or more resource pools during the inactive duration of the DRX cycle based on the group sidelink DRX configuration. In some examples, the resource pool component 1045 may avoid monitoring one or more resource pools associated with monitoring the sidelink channel for discovery signals based on the group resource pool configuration associated with monitoring discovery signals.

[0205] The synchronization component 1050 may synchronize with the group of UEs based on synchronization signals received from at least one UE associated with the group of UEs on the sidelink broadcast channel. In some examples, the synchronization component 1050 may send synchronization signals to a second UE on the sidelink broadcast channel. In some examples, the synchronization component 1050 may synchronize with the second UE based on the synchronization signals. The sidelink component 1055 may establish a connection with the second UE to relay the communication of the UE, where the relayed communication corresponds to an L2 forwarding function or an L3 forwarding function.

[0206] Figure 11FIG. shows a system 1100 including a device 1105 according to one or more aspects of the present disclosure. The device 1105 may be an example of a component of the device 805, the device 905, or the UE 115 described herein or include these components. The device 1105 may include components for two-way voice and data communication, including components for sending and receiving communications, including a UE communication manager 1110, an I / O controller 1115, a transceiver 1120, an antenna 1125, a memory 1130, and a processor 1140. These components may communicate electronically via one or more buses (e.g., bus 1145).

[0207] The UE communication manager 1110 may send sidelink DRX information to a base station when operating in a connected mode. The UE communication manager 1110 may receive a message including a sidelink DRX configuration from the base station based on the sidelink DRX information and operate according to the sidelink DRX configuration.

[0208] The UE communication manager 1110 may also receive a message including a group sidelink DRX configuration associated with a group of UEs when operating in an out-of-coverage mode, an idle mode, or an inactive mode. The UE communication manager 1110 may determine a time period for enabling discontinuous monitoring of a sidelink channel based on the group sidelink DRX configuration and monitor the sidelink channel during the time period.

[0209] The UE communication manager 1110 may also determine a DRX cycle based on the sidelink DRX configuration, the DRX cycle including an active duration and an inactive duration. The UE communication manager 1110 may receive a discovery request message from a second UE during the active duration of the DRX cycle and send a discovery response message to the second UE during the active duration of the DRX cycle.

[0210] The I / O controller 1115 may manage the input and output signals of the device 1105. The I / O controller 1115 may also manage peripheral devices not integrated into the device 1105. In some cases, the I / O controller 1115 may represent a physical connection or port to an external peripheral device. In some cases, the I / O controller 1115 may use an operating system such as or other known operating systems. In other cases, the I / O controller 1115 may represent a modem, a keyboard, a mouse, a touch screen, or a similar device or interact with these devices. In some cases, the I / O controller 1115 may be implemented as part of a processor. In some cases, a user may interact with the device 1105 via the I / O controller 1115 or via a hardware component controlled by the I / O controller 1115.

[0211] As described above, the transceiver 1120 can perform two-way communication via one or more antennas, wired or wireless links. For example, the transceiver 1120 can represent a wireless transceiver and can perform two-way communication with another wireless transceiver. The transceiver 1120 can also include a modem that is used to modulate packets and provide the modulated packets to the antenna for transmission, and to demodulate packets received from the antenna. In some cases, the device 1105 can include a single antenna 1125. However, in some cases, the device 1105 can have more than one antenna 1125, which can be capable of simultaneously transmitting or receiving multiple wireless transmissions.

[0212] The memory 1130 can include RAM and ROM. The memory 1130 can store computer-readable, computer-executable code 1135, which includes instructions that, when executed, cause the processor 1140 to perform the various functions described herein. In some cases, among other things, the memory 1130 can contain BIOS, which can control basic hardware or software operations, such as interactions with peripheral components or devices.

[0213] The code 1135 can include instructions for implementing various aspects of the present disclosure, including instructions for supporting wireless communication. The code 1135 can be stored in a non-transitory computer-readable medium such as system memory or other types of memory. In some cases, the code 1135 may not be directly executable by the processor 1140, but can cause a computer (e.g., when compiled and executed) to perform the functions described herein.

[0214] The processor 1140 can include intelligent hardware devices (e.g., general-purpose processors, DSPs, CPUs, microcontrollers, ASICs, FPGAs, programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, or any combination thereof). In some cases, the processor 1140 can be configured to operate a memory array using a memory controller. In other cases, the memory controller can be integrated into the processor 1140. The processor 1140 can be configured to execute computer-readable instructions stored in a memory (e.g., the memory 1130) to cause the device 1105 to perform various functions (e.g., functions or tasks supporting DRX for sidelink communication in a wireless communication system).

[0215] Figure 12FIG. 1200 shows a block diagram of a device 1205 in accordance with one or more aspects of the present disclosure. The device 1205 may be an example of an aspect of the base station 105 as described herein. The device 1205 may include a receiver 1210, a base station communication manager 1215, and a transmitter 1220. The device 1205 may also include a processor. Each of these components may communicate with each other (e.g., via one or more buses).

[0216] The receiver 1210 may receive information such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information related to DRX for sidelink communication in a wireless communication system). The information may be passed to other components of the device 1205. The receiver 1210 may be an example of aspects of the transceiver 1520 described in reference Figure 15 The receiver 1210 may use a single antenna or an antenna array.

[0217] The base station communication manager 1215 may receive sidelink DRX information from a UE, determine a sidelink DRX mode for the UE based on the sidelink DRX information, and transmit a message including a sidelink DRX configuration that includes an indication of the sidelink DRX mode for the UE. The base station communication manager 1215 may be an example of an aspect of the base station communication manager 1510 described herein.

[0218] The base station communication manager 1215 or its subcomponents may be implemented in hardware, code executed by a processor (e.g., software or firmware), or any combination thereof. If implemented in code executed by a processor, the functions of the base station communication manager 1215 or its subcomponents may be performed by a general-purpose processor, a DSP, an application-specific integrated circuit (ASIC), an FPGA, or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described in the present disclosure.

[0219] The base station communication manager 1215 or its subcomponents may physically be located in various positions, including distributed such that portions of the functionality are implemented by one or more physical components in different physical locations. In some examples, in accordance with various aspects of the present disclosure, the base station communication manager 1215 or its subcomponents may be separate and distinct components. In some examples, in accordance with various aspects of the present disclosure, the base station communication manager 1215 or its subcomponents may be combined with one or more other hardware components, including but not limited to input / output (I / O) components, transceivers, network servers, another computing device, one or more other components described in the present disclosure, or a combination thereof.

[0220] Transmitter 1220 can send signals generated by other components of device 1205. In some examples, transmitter 1220 can be co-located with receiver 1210 in a transceiver module. For example, transmitter 1220 can be an example of aspects of transceiver 1520 described with reference to Figure 15 Transmitter 1220 can use a single antenna or an antenna array.

[0221] Figure 13 Block diagram 1300 of device 1305 is shown in accordance with one or more aspects of the present disclosure. Device 1305 can be an example of aspects of device 1205 or base station 105 described herein. Device 1305 can include: receiver 1310, base station communication manager 1315, and transmitter 1330. Device 1305 can also include a processor. Each of these components can communicate with each other (e.g., via one or more buses).

[0222] Receiver 1310 can receive information such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information related to DRX for sidelink communication in a wireless communication system). The information can be passed to other components of device 1305. Receiver 1310 can be an example of aspects of transceiver 1520 described with reference to Figure 15 Receiver 1310 can use a single antenna or an antenna array.

[0223] Base station communication manager 1315 can be an example of aspects of base station communication manager 1215 described herein. Base station communication manager 1315 can include sidelink information component 1320 and sidelink configuration component 1325. Base station communication manager 1315 can be an example of aspects of base station communication manager 1510 described herein. Sidelink information component 1320 can receive sidelink DRX information from a UE. Sidelink configuration component 1325 can determine a sidelink DRX mode for the UE based on the sidelink DRX information and send a message including a sidelink DRX configuration that includes an indication of the sidelink DRX mode for the UE.

[0224] Transmitter 1330 can send signals generated by other components of device 1305. In some examples, transmitter 1330 can be co-located with receiver 1310 in a transceiver module. For example, transmitter 1330 can be an example of aspects of transceiver 1520 described with reference to Figure 15 Transmitter 1330 can use a single antenna or an antenna array.

[0225] Figure 14FIG. 1400 is a block diagram of a base station communication manager 1405 in accordance with one or more aspects of the present disclosure. The base station communication manager 1405 may be an example of aspects of the base station communication manager 1215, the base station communication manager 1315, or the base station communication manager 1510 described herein. The base station communication manager 1405 may include a sidelink information component 1410, a sidelink configuration component 1415, and a mode component 1420. Each of these modules may communicate directly or indirectly with each other (e.g., via one or more buses).

[0226] The sidelink information component 1410 may receive sidelink DRX information from a UE. In some examples, the sidelink information component 1410 may receive a UAI from the UE that includes the sidelink DRX information. The sidelink configuration component 1415 may determine a sidelink DRX mode for the UE based on the sidelink DRX information. In some examples, the sidelink configuration component 1415 may send a message that includes a sidelink DRX configuration that includes an indication of the sidelink DRX mode for the UE. In some examples, the sidelink configuration component 1415 may send an RRC reconfiguration message to the UE that includes the sidelink DRX configuration. In some examples, the sidelink configuration component 1415 may receive an RRC reconfiguration complete message from the UE based on the RRC reconfiguration message. In some cases, the sidelink DRX configuration includes a connected mode DRX configuration. In some cases, the sidelink DRX configuration includes a sidelink DRX preference.

[0227] The mode component 1420 may determine a sidelink DRX mode for the UE based on a resource pool configuration for the UE. In some examples, the mode component 1420 may determine a first sidelink DRX mode associated with a sidelink DRX configuration for monitoring a sidelink channel for discovery signals at the UE based on the sidelink DRX information. In some examples, the mode component 1420 may determine a second sidelink DRX mode associated with a sidelink DRX configuration for receiving a downlink signal from the base station at the UE based on the sidelink DRX information, where the first sidelink DRX mode is different from the second sidelink DRX mode.

[0228] Figure 15FIG. showing a system 1500 including a device 1505 according to one or more aspects of the present disclosure. The device 1505 may be an example of or include components such as the device 1205, the device 1305, or the base station 105 described herein. The device 1505 may include components for two-way voice and data communication, including components for sending and receiving communications, including a base station communication manager 1510, a network communication manager 1515, a transceiver 1520, an antenna 1525, a memory 1530, a processor 1540, and an inter-station communication manager 1545. These components may communicate electronically via one or more buses (e.g., bus 1550).

[0229] The base station communication manager 1510 may receive sidelink DRX information from a UE, determine a sidelink DRX mode for the UE based on the sidelink DRX information, and send a message including a sidelink DRX configuration that includes an indication of the sidelink DRX mode for the UE.

[0230] The network communication manager 1515 may manage communication with the core network (e.g., via one or more wired backhaul links). For example, the network communication manager 1515 may manage the transmission of data communication for client devices such as one or more UEs 115.

[0231] As described above, the transceiver 1520 may communicate bidirectionally via one or more antennas, wired or wireless links. For example, the transceiver 1520 may represent a wireless transceiver and may communicate bidirectionally with another wireless transceiver. The transceiver 1520 may also include a modem for modulating packets and providing the modulated packets to the antenna for transmission, and for demodulating packets received from the antenna. In some cases, the device 1505 may include a single antenna 1525. However, in some cases, the device 1505 may have more than one antenna 1525, which may be capable of simultaneously sending or receiving multiple wireless transmissions.

[0232] The memory 1530 may include RAM, ROM, or a combination thereof. The memory 1530 may store computer-readable code 1535, which includes instructions that, when executed by a processor (e.g., processor 1540), cause the device to perform various functions described herein. In some cases, among other things, the memory 1530 may contain a BIOS that may control basic hardware or software operations, such as interactions with peripheral components or devices.

[0233] Code 1535 may include instructions for implementing aspects of the present disclosure, including instructions for supporting wireless communication. Code 1535 may be stored in a non-transitory computer-readable medium such as system memory or other types of memory. In some cases, code 1535 may not be directly executable by the processor 1540, but may cause a computer (e.g., when compiled and executed) to perform the functions described herein.

[0234] The processor 1540 may include intelligent hardware devices (e.g., a general-purpose processor, a DSP, a CPU, a microcontroller, an ASIC, an FPGA, a programmable logic device, discrete gate or transistor logic components, discrete hardware components, or any combination thereof). In some cases, the processor 1540 may be configured to operate a memory array using a memory controller. In some cases, the memory controller may be integrated into the processor 1540. The processor 1540 may be configured to execute computer-readable instructions stored in a memory (e.g., memory 1530) to cause the device 1505 to perform various functions (e.g., functions or tasks supporting DRX for sidelink communication in a wireless communication system).

[0235] The inter-station communication manager 1545 may manage communication with other base stations 105 and may include a controller or scheduler for cooperating with other base stations 105 to control communication with the UE 115. For example, the inter-station communication manager 1545 may coordinate the scheduling of transmissions to the UE 115 for various interference mitigation techniques such as beamforming and / or joint transmission. In some examples, the inter-station communication manager 1545 may provide an X2 interface within the LTE / LTE-A wireless communication network technology to provide communication between the base stations 105.

[0236] Figure 16 A flowchart illustrating a method 1600 in accordance with one or more aspects of the present disclosure is shown. As described herein, the operations of method 1600 may be implemented by the UE 115 or its components. For example, the operations of method 1600 may be performed by the UE communication manager described with reference to Figures 8 to 11 In some examples, the UE may execute an instruction set to control functional units of the UE to perform the functions described below. Additionally or alternatively, the UE may perform aspects of the functions described below using dedicated hardware.

[0237] At 1605, the UE may send sidelink DRX information to a base station while operating in a connected mode. The operation of 1605 may be performed according to the methods described herein. In some examples, some aspects of the operation of 1605 may be performed by the sidelink information component described with reference to Figures 8 to 11 as described.

[0238] At 1610, the UE can receive a message including a sidelink DRX configuration from the base station based on the sidelink DRX information. The operation of 1610 can be performed according to the methods described herein. In some examples, some aspects of the operation of 1610 can be performed by the sidelink configuration component referred to Figures 8 to 11 as described.

[0239] At 1615, the UE can operate according to the sidelink DRX configuration. The operation of 1615 can be performed according to the methods described herein. In some examples, some aspects of the operation of 1615 can be performed by the mode component referred to Figures 8 to 11 as described.

[0240] Figure 17 A flowchart illustrating a method 1700 in accordance with one or more aspects of the present disclosure is shown. As described herein, the operations of method 1700 can be implemented by the UE 115 or its components. For example, the operations of method 1700 can be performed by the UE communication manager referred to Figures 8 to 11 as described. In some examples, the UE can execute an instruction set to control the functional units of the UE to perform the functions described below. Additionally or alternatively, the UE can perform aspects of the functions described below using dedicated hardware.

[0241] At 1705, the UE can receive a message including a group sidelink DRX configuration associated with a group of UEs when operating in an out-of-coverage mode, an idle mode, or an inactive mode. The operation of 1705 can be performed according to the methods described herein. In some examples, some aspects of the operation of 1705 can be performed by the sidelink configuration component referred to Figures 8 to 11 as described.

[0242] At 1710, the UE can determine a time period for enabling discontinuous monitoring of the sidelink channel based on the group sidelink DRX configuration. The operation of 1710 can be performed according to the methods described herein. In some examples, some aspects of the operation of 1710 can be performed by the mode component referred to Figures 8 to 11 as described.

[0243] At 1715, the UE can monitor the sidelink channel during the time period. The operation of 1715 can be performed according to the methods described herein. In some examples, some aspects of the operation of 1715 can be performed by the mode component referred to Figures 8 to 11 as described.

[0244] Figure 18A flowchart illustrating method 1800 in accordance with one or more aspects of the present disclosure is shown. As described herein, the operations of method 1800 may be implemented by UE 115 or its components. For example, the operations of method 1800 may be performed by the UE communication manager described with reference to Figures 8 to 11 The UE communication manager described. In some examples, the UE may execute an instruction set to control functional units of the UE to perform the functions described below. Additionally or alternatively, the UE may perform aspects of the functions described below using dedicated hardware.

[0245] At 1805, the UE may determine a DRX cycle based on a sidelink DRX configuration, the DRX cycle including an active duration and an inactive duration. The operation at 1805 may be performed according to the methods described herein. In some examples, some aspects of the operation at 1805 may be performed by the sidelink configuration component described with reference to Figures 8 to 11 The sidelink configuration component described.

[0246] At 1810, the UE may receive a discovery request message from a second UE during the active duration of the DRX cycle. The operation at 1810 may be performed according to the methods described herein. In some examples, some aspects of the operation at 1810 may be performed by the discovery component described with reference to Figures 8 to 11 The discovery component described.

[0247] At 1815, the UE may send a discovery response message to the second UE during the active duration of the DRX cycle. The operation at 1815 may be performed according to the methods described herein. In some examples, some aspects of the operation at 1815 may be performed by the discovery component described with reference to Figures 8 to 11 The discovery component described.

[0248] Figure 19 A flowchart illustrating method 1900 in accordance with one or more aspects of the present disclosure is shown. As described herein, the operations of method 1900 may be implemented by base station 105 or its components. For example, the operations of method 1900 may be performed by the base station communication manager described with reference to Figures 12 to 15 The base station communication manager described. In some examples, the base station may execute an instruction set to control functional units of the base station to perform the functions described below. Additionally or alternatively, the base station may perform aspects of the functions described below using dedicated hardware.

[0249] At 1905, the base station may receive sidelink DRX information from a UE. The operation at 1905 may be performed according to the methods described herein. In some examples, some aspects of the operation at 1905 may be performed by the sidelink information component described with reference to Figures 12 to 15 The sidelink information component described.

[0250] At 1910, the base station may determine a sidelink DRX mode for a UE based on sidelink DRX information. The operation of 1910 may be performed according to the methods described herein. In some examples, some aspects of the operation of 1910 may be performed by a sidelink configuration component referenced Figures 12 to 15 as described.

[0251] At 1915, the base station may send a message including a sidelink DRX configuration that includes an indication of the sidelink DRX mode for the UE. The operation of 1915 may be performed according to the methods described herein. In some examples, some aspects of the operation of 1915 may be performed by a sidelink configuration component referenced Figures 12 to 15 as described.

[0252] It should be noted that: the methods described herein describe possible implementations, and the operations and steps may be rearranged or otherwise modified, and other implementations are possible. Additionally, aspects from two or more of these methods may be combined.

[0253] An overview of examples of the present disclosure is provided below:

[0254] Example 1: A method for wireless communication at a UE is described. The method may include: sending sidelink discontinuous reception information to a base station when operating in a connected mode; receiving, at least in part based on the sidelink discontinuous reception information, a message including a sidelink discontinuous reception configuration from the base station; and operating according to the sidelink discontinuous reception configuration.

[0255] Example 2: The method according to Example 1, further comprising: monitoring a sidelink channel to receive a discovery signal from a second UE during an active duration of a discontinuous reception period, at least in part based on the sidelink discontinuous reception configuration; and receiving the discovery signal from the second UE, at least in part based on the monitoring.

[0256] Example 3: The method according to Example 1 or Example 2, wherein the sidelink discontinuous reception configuration is at least in part based on a discovery resource pool corresponding to time and frequency resources associated with monitoring the sidelink channel to receive the discovery signal from the second UE.

[0257] Example 4: The method according to Examples 2 to 3 further includes: broadcasting a discovery request message during the active duration of the discontinuous reception period at least partially based on the sidelink discontinuous reception configuration; monitoring the sidelink channel during the active duration of the discontinuous reception period to receive a discovery response message from the second UE; and receiving the discovery response message from the second UE at least partially based on the monitoring, the discovery signal including the discovery response message.

[0258] Example 5: The method according to Examples 2 to 4 further includes: selecting the second UE for relay communication between the UE and the base station or between the UE and a third UE or both at least partially based on the discovery signal, wherein the relay communication corresponds to a layer 2 (L2) forwarding function or a layer 3 (L3) forwarding function.

[0259] Example 6: The method according to Examples 2 to 5 further includes: determining a sidelink discontinuous reception mode for monitoring the sidelink channel to receive the discovery signal from the second UE at least partially based on the sidelink discontinuous reception configuration, the sidelink discontinuous reception mode including the discontinuous reception period, the discontinuous reception period including the active duration and the inactive duration.

[0260] Example 7: The method according to Examples 2 to 6 further includes: receiving a synchronization signal from the second UE on a sidelink broadcast channel; and synchronizing with the second UE at least partially based on the synchronization signal.

[0261] Example 8: The method according to Examples 1 to 7 further includes: receiving a downlink signal from the base station using a cellular link at least partially based on the sidelink discontinuous reception configuration; or transmitting an uplink signal to the base station using the cellular link at least partially based on the sidelink discontinuous reception configuration.

[0262] Example 9: The method according to Example 8 further includes: determining a sidelink discontinuous reception mode for receiving the downlink signal or transmitting the uplink signal or both at least partially based on the sidelink discontinuous reception configuration, the sidelink discontinuous reception mode including a discontinuous reception period, the discontinuous reception period including an active duration and an inactive duration, wherein receiving the downlink signal or transmitting the uplink signal or both is at least partially based on the sidelink discontinuous reception mode.

[0263] Example 10: In the method according to Examples 1 to 9, receiving the message includes: receiving a radio resource control reconfiguration message including the sidelink discontinuous reception configuration from the base station.

[0264] Example 11: The method according to Example 10 further includes: sending a radio resource control reconfiguration complete message to the base station at least in part based on the radio resource control reconfiguration message, wherein operating according to the sidelink discontinuous reception configuration is at least in part based on the radio resource control reconfiguration complete message.

[0265] Example 12: The method according to Examples 1 to 11 further includes: including the sidelink discontinuous reception information in UE assistance information; and sending the UE assistance information including the sidelink discontinuous reception information to the base station when operating in the connected mode, wherein receiving the message including the sidelink discontinuous reception configuration is at least in part based on the UE assistance information.

[0266] Example 13: The method according to Examples 1 to 12 further includes: determining a single connection mode discontinuous reception period for sidelink communication or cellular communication or both at least in part based on the sidelink discontinuous reception configuration, wherein operating according to the sidelink discontinuous reception configuration is at least in part based on the single connection mode discontinuous reception period.

[0267] Example 14: The method according to Examples 1 to 13 further includes: determining a discontinuous reception period at least in part based on a relay service associated with a second UE or a quality of service associated with the UE's data traffic or both, wherein the sidelink discontinuous reception information includes an indication of the discontinuous reception period.

[0268] Example 15: The method according to Examples 1 to 14 further includes: determining a value of an active timer associated with the discontinuous reception period at least in part based on a relay service associated with a second UE or a quality of service associated with the UE's data traffic or both, wherein the sidelink discontinuous reception information includes an indication of the value of the active timer associated with the discontinuous reception period.

[0269] Example 16: The method according to Examples 1 to 15 further includes: determining a value of an inactive timer associated with the discontinuous reception period at least in part based on a relay service associated with a second UE or a quality of service associated with the UE's data traffic or both, wherein the sidelink discontinuous reception information includes an indication of the value of the inactive timer associated with the discontinuous reception period.

[0270] Example 17: The method according to any one of Examples 1 to 16 further includes: determining an offset between the start of a discontinuous reception period and the start of an active duration of the discontinuous reception period based at least in part on a relay service associated with a second UE or a quality of service associated with data traffic for the UE or both, wherein the sidelink discontinuous reception information includes an indication of the offset.

[0271] Example 18: The method according to any one of Examples 1 to 17 further includes: determining a first sidelink discontinuous reception mode associated with the sidelink discontinuous reception configuration for monitoring a sidelink channel to receive a discovery signal based at least in part on the sidelink discontinuous reception configuration; and determining a second sidelink discontinuous reception mode associated with the sidelink discontinuous reception configuration for receiving a downlink signal from the base station or transmitting an uplink signal to the base station or both based at least in part on the sidelink discontinuous reception configuration, wherein the first sidelink discontinuous reception mode is different from the second sidelink discontinuous reception mode.

[0272] Example 19: The method according to Example 18, wherein the sidelink discontinuous reception configuration includes a first indication of the first sidelink discontinuous reception mode or a second indication of the second sidelink discontinuous reception mode, or both.

[0273] Example 20: The method according to any one of Examples 1 to 19, wherein the sidelink discontinuous reception configuration includes a connected mode discontinuous reception configuration.

[0274] Example 21: The method according to any one of Examples 1 to 20, wherein the sidelink discontinuous reception configuration includes a sidelink discontinuous reception preference associated with a discovery process including a first model discovery process or a second model discovery process.

[0275] Example 22: The method according to any one of Examples 1 to 21, wherein the sidelink discontinuous reception configuration includes a sidelink discontinuous reception preference associated with receiving a downlink signal from the base station or transmitting an uplink signal to the base station or both.

[0276] Example 23: The method according to any one of Examples 1 to 22, wherein the UE includes a remote UE, and the second UE includes a relay UE between the remote UE and the base station.

[0277] Example 24: Describes a method for wireless communication at a UE. The method may include: when operating in an out-of-coverage mode, an idle mode, or an inactive mode, receiving a message including a group sidelink discontinuous reception configuration associated with a group of UEs; determining, at least in part based on the group sidelink discontinuous reception configuration, a time period during which discontinuous monitoring of a sidelink channel can be performed; and monitoring the sidelink channel during the time period.

[0278] Example 25: The method according to Example 24, wherein receiving the message includes: receiving a system information block or a radio resource control reconfiguration message including the group sidelink discontinuous reception configuration.

[0279] Example 26: The method according to Example 25, further comprising: enabling discontinuous monitoring of the sidelink channel, at least in part based on the system information block or the radio resource control reconfiguration message.

[0280] Example 27: The method according to Example 25, further comprising: disabling the discontinuous reception mode, at least in part based on a quality of service associated with pending data traffic meeting a quality of service threshold.

[0281] Example 28: The method according to Examples 24 to 27, wherein the group sidelink discontinuous reception configuration includes a discontinuous reception period common to the group of UEs.

[0282] Example 29: The method according to Examples 24 to 28, wherein the sidelink discontinuous reception configuration includes a duration of activity of the discontinuous reception period common to the group of UEs.

[0283] Example 30: The method according to Examples 24 to 29, wherein the sidelink discontinuous reception configuration includes a group offset duration between a start of the discontinuous reception period and the duration of activity of the discontinuous reception period, wherein the group offset duration is common to the group of UEs.

[0284] Example 31: The method according to Examples 24 to 30, wherein the time period is common to the group of UEs.

[0285] Example 32: The method according to Examples 24 to 31, wherein the UEs are grouped into the group of UEs, at least in part based on a path loss parameter.

[0286] Example 33: The method according to Examples 24 to 32, wherein the UEs are grouped into the group of UEs, at least in part based on a quality of service associated with data traffic of the UEs.

[0287] Example 34: The method according to Examples 24 to 22 further includes: determining a UE-specific offset duration associated with an active duration of a discontinuous reception period at least in part based on the sidelink discontinuous reception configuration, wherein monitoring the sidelink channel includes: monitoring the sidelink channel during the active duration of the discontinuous reception period at least in part based on the UE-specific offset duration.

[0288] Example 35: The method according to Example 34, wherein the UE-specific offset duration is at least in part based on a layer 2 (L2) identifier associated with the UE.

[0289] Example 36: The method according to Examples 24 to 35 further includes: enabling a discontinuous reception mode at least in part based on the message.

[0290] Example 37: The method according to Examples 24 to 36 further includes: enabling a discontinuous reception mode at least in part based on a quality of service associated with pending data traffic meeting a quality of service threshold.

[0291] Example 38: The method according to Examples 24 to 37 further includes: enabling a discontinuous reception mode at least in part based on a power level of the UE meeting a power level threshold.

[0292] Example 39: The method according to Examples 24 to 38 further includes: avoiding monitoring one or more resource pools during an inactive duration of a discontinuous reception period at least in part based on the group sidelink discontinuous reception configuration.

[0293] Example 40: The method according to Examples 24 to 39 further includes: avoiding monitoring one or more resource pools associated with monitoring the sidelink channel for a discovery signal at least in part based on a group resource pool configuration associated with monitoring the discovery signal.

[0294] Example 41: The method according to Examples 24 to 40 further includes: broadcasting a discovery request message during an inactive duration of a discontinuous reception period associated with a group of UEs at least in part based on a data traffic condition of the UE, wherein the inactive duration is common to the group of UEs, and wherein the inactive duration and the discontinuous reception period are common to the group of UEs.

[0295] Example 42: The method according to any one of Examples 24 to 41 further includes: receiving a downlink signal from a base station during an inactivity duration of a discontinuous reception period associated with the group of UEs; or transmitting an uplink signal to the base station during the inactivity duration of the discontinuous reception period associated with the group of UEs, wherein the inactivity duration and the discontinuous reception period are common to the group of UEs.

[0296] Example 43: The method according to any one of Examples 24 to 42 further includes: synchronizing with the group of UEs at least in part based on a synchronization signal received from at least one UE associated with the group of UEs on a sidelink broadcast channel.

[0297] Example 44: A method for wireless communication at a UE is described. The method may include: determining a discontinuous reception period at least in part based on a sidelink discontinuous reception configuration, the discontinuous reception period including an active duration and an inactivity duration; receiving a discovery request message from a second UE during the active duration of the discontinuous reception period; and transmitting a discovery response message to the second UE during the active duration of the discontinuous reception period.

[0298] Example 45: The method according to Example 44, wherein the sidelink discontinuous reception configuration is at least in part based on a discovery resource pool corresponding to time and frequency resources for receiving the discovery request message or transmitting the discovery response message or both.

[0299] Example 46: The method according to Example 44 or 45 further includes: establishing a connection with the second UE to relay communication for the UE, wherein the relayed communication corresponds to a layer 2 (L2) forwarding function or a layer 3 (L3) forwarding function.

[0300] Example 47: The method according to any one of Examples 44 to 46 further includes: transmitting a synchronization signal to the second UE on a sidelink broadcast channel; and synchronizing with the second UE at least in part based on the synchronization signal.

[0301] Example 48: A method for wireless communication at a base station is described. The method may include: receiving sidelink discontinuous reception information from a UE; determining a sidelink discontinuous reception mode for the UE at least in part based on the sidelink discontinuous reception information; and transmitting a message including a sidelink discontinuous reception configuration, the sidelink discontinuous reception configuration including an indication of the sidelink discontinuous reception mode for the UE.

[0302] Example 49: The method according to Example 48, wherein sending the message comprises: sending a radio resource control reconfiguration message including the sidelink discontinuous reception configuration to the UE.

[0303] Example 50: The method according to Example 49, further comprising: receiving a radio resource control reconfiguration complete message from the base station at least in part based on the radio resource control reconfiguration message.

[0304] Example 51: The method according to Examples 48 to 50, further comprising: receiving UE assistance information including the sidelink discontinuous reception information from the UE.

[0305] Example 52: The method according to Examples 48 to 51, further comprising: determining the sidelink discontinuous reception mode for the UE at least in part based on the resource pool configuration for the UE.

[0306] Example 53: The method according to Examples 48 to 52, further comprising: determining a first sidelink discontinuous reception mode associated with the sidelink discontinuous reception configuration for monitoring the sidelink channel for discovery signals at the UE at least in part based on the sidelink discontinuous reception information; and determining a second sidelink discontinuous reception mode associated with the sidelink discontinuous reception configuration for receiving downlink signals from the base station at the UE at least in part based on the sidelink discontinuous reception information, wherein the first sidelink discontinuous reception mode is different from the second sidelink discontinuous reception mode.

[0307] Example 54: The method according to Examples 48 to 53, wherein the sidelink discontinuous reception configuration includes a connected mode discontinuous reception configuration.

[0308] Example 55: The method according to Examples 48 to 54, wherein the sidelink discontinuous reception configuration includes a sidelink discontinuous reception preference.

[0309] Example 56: An apparatus for wireless communication, comprising a processor; and a memory coupled to the processor; the processor and the memory being configured to perform the method according to any one of Examples 1 - 23.

[0310] Example 57: An apparatus for wireless communication, comprising at least one unit for performing the method according to any one of Examples 1 - 23.

[0311] Example 58: A computer-readable medium storing code for wireless communication, the code including instructions executable by a processor to perform the method according to any one of Examples 1 - 23.

[0312] Example 59: A device for wireless communication, comprising a processor; and a memory coupled to the processor; the processor and the memory are configured to execute the method described in any of Examples 24 - 43.

[0313] Example 60: A device for wireless communication, comprising at least one unit for executing the method described in any of Examples 24 - 43.

[0314] Example 61: A computer - readable medium storing code for wireless communication, the code comprising instructions executable by a processor to execute the method described in any of Examples 24 - 43.

[0315] Example 62: A device for wireless communication, comprising a processor; and a memory coupled to the processor; the processor and the memory are configured to execute the method described in any of Examples 44 - 47.

[0316] Example 63: A device for wireless communication, comprising at least one unit for executing the method described in any of Examples 44 - 47.

[0317] Example 64: A computer - readable medium storing code for wireless communication, the code comprising instructions executable by a processor to execute the method described in any of Examples 44 - 47.

[0318] Example 65: A device for wireless communication, comprising a processor; and a memory coupled to the processor; the processor and the memory are configured to execute the method described in any of Examples 48 - 55.

[0319] Example 66: A device for wireless communication, comprising at least one unit for executing the method described in any of Examples 48 - 55.

[0320] Example 67: A computer - readable medium storing code for wireless communication, the code comprising instructions executable by a processor to execute the method described in any of Examples 48 - 55.

[0321] Although some aspects of LTE, LTE-A, LTE-A Pro, or NR systems may be described for purposes of example, and the LTE, LTE-A, LTE-A Pro, or NR terms may be used in much of the description, the techniques described herein are applicable beyond LTE, LTE-A, LTE-A Pro, or NR networks. For example, the described techniques may be applicable to a variety of other wireless communication systems such as Ultra Mobile Broadband (UMB), Institute of Electrical and Electronics Engineers (IEEE) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, Flash-OFDM, and other systems and radio technologies not explicitly mentioned herein.

[0322] Any of a variety of different techniques and methods may be used to represent the information and signals described herein. For example, data, instructions, commands, information, signals, bits, symbols, and chips referred to throughout this specification may be represented by voltage, current, electromagnetic waves, magnetic fields or magnetic particles, optical fields or optical particles, or any combination thereof.

[0323] The various illustrative blocks and components described in connection with the disclosure herein may be implemented or performed using a general purpose processor, DSP, ASIC, CPU, FPGA, or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof. The general purpose processor may be a microprocessor, but in the alternative, the processor may be any processor, controller, microcontroller, or state machine. The processor may also be implemented as a combination of computing devices (e.g., a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration).

[0324] The functions described herein may be implemented in hardware, software executed by a processor, firmware, or any combination thereof. If implemented in software executed by a processor, the functions may be stored on or transmitted via a computer-readable medium as one or more instructions or code. Other examples and implementations are within the scope of the present disclosure and the appended claims. For example, due to the nature of software, the functions described herein may be implemented using software executed by a processor, hardware, firmware, hardwiring, or any combination thereof. The features implementing the functions may also be physically located in various places, including being distributed such that portions of the functions are implemented at different physical locations.

[0325] A computer-readable medium includes both a non-transitory computer storage medium and a communication medium, where the communication medium includes any medium that facilitates transfer of a computer program from one location to another. The non-transitory storage medium can be any available medium that can be accessed by a general purpose or special purpose computer. By way of example, and not limitation, the non-transitory computer-readable medium can include random access memory (RAM), read only memory (ROM), electrically erasable programmable ROM (EEPROM), flash memory, compact disc (CD) ROM or other optical disc storage, magnetic disk storage or other magnetic storage devices, or any other non-transitory medium that can be used to carry or store desired program code units in the form of instructions or data structures and that can be accessed by a general purpose or special purpose computer or a general purpose or special purpose processor. Additionally, any connection can be properly termed a computer-readable medium. For example, if software is transmitted from a website, server, or other remote source using coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of computer-readable medium. As used herein, disk and disc include CD, laser disc, optical disc, digital versatile disc (DVD), floppy disk, and Blu-ray disc, where disks typically reproduce data magnetically, while discs reproduce data optically with lasers. Combinations of the above should also be included within the scope of computer-readable medium.

[0326] As used herein, including in the claims, the term "or" as used in a list of items (e.g., in a list of items preceded by phrases such as "at least one of" or "one or more of") refers to an inclusive list, such that, for example, a list of at least one of A, B, or C means A, or B, or C, or AB, or AC, or BC, or ABC (i.e., A and B and C). Additionally, as used herein, the phrase "based on" should not be construed as a reference to a closed set of conditions. For example, an example step described as "based on condition A" can be based on both condition A and condition B without departing from the scope of the present disclosure. In other words, as used herein, the phrase "based on" will be interpreted in the same manner as the phrase "at least partially based on".

[0327] In the figures, similar components or features may have the same reference numeral. Additionally, each of the same type of components can be distinguished by following the reference numeral with a dash and a second numeral used to differentiate among similar components. If only the first reference numeral is used in this specification, then the description applies to any one of the similar components having the same first reference numeral, regardless of the second reference numeral or any other subsequent reference numerals.

[0328] The description of the specification set forth herein in conjunction with the accompanying drawings describes exemplary configurations and does not represent all of the examples that can be implemented or that are within the scope of the claims. The term "example" as used herein means "serving as an example, instance, or illustration" and is not "preferred" or "advantageous" as compared to other examples. To provide an understanding of the described technology, the detailed description includes specific details. However, the technology may be practiced without these specific details. In some instances, well-known structures and devices are shown in block diagram form in order to avoid obscuring the concepts of the described examples.

[0329] The description herein is provided to enable a person of ordinary skill in the art to make or use the disclosure. Various modifications to the present disclosure will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other variations without departing from the scope of the present disclosure. Thus, the present disclosure is not limited to the examples and designs described herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A device for wireless communication, comprising: one or more memories; and one or more processors, the one or more processors being coupled to the one or more memories and configured to: send sidelink discontinuous reception information to a network entity; receive, at least in part based on the sidelink discontinuous reception information, a message including a sidelink discontinuous reception configuration from the network entity, the sidelink discontinuous reception configuration being for discovering a user equipment (UE); and communicate according to the sidelink discontinuous reception configuration.

2. The device according to claim 1, wherein, The one or more processors are further configured to: send a first discovery message during an active duration of a discontinuous reception period, at least in part based on the sidelink discontinuous reception configuration; monitor a sidelink channel to receive a second discovery message from the UE during the active duration of the discontinuous reception period; and receive the second discovery message from the UE.

3. The device according to claim 2, wherein The sidelink discontinuous reception configuration is at least in part based on a discovery resource pool associated with the sidelink channel for receiving the second discovery message from the UE.

4. A device for wireless communication, comprising: one or more memories; and one or more processors, the one or more processors being coupled to the one or more memories and configured to: receive, at least in part based on being in an out-of-coverage mode, idle mode, or inactive mode, a message including a group sidelink discontinuous reception configuration associated with a group of UEs; and monitor a sidelink channel during a time period, the time period being at least in part based on the group sidelink discontinuous reception configuration.

5. The apparatus according to claim 4, wherein, To receive the message, the one or more processors are configured to: receive a system information or radio resource control reconfiguration message including the group sidelink discontinuous reception configuration.

6. A device for wireless communication, comprising: one or more memories; and one or more processors, the one or more processors being coupled to the one or more memories and configured to: transfer a first discovery message to a user equipment (UE) during an active duration of a discontinuous reception period, the discontinuous reception period being at least in part based on a sidelink discontinuous reception configuration; and transfer a second discovery message to the UE during the active duration of the discontinuous reception period.

7. The apparatus according to claim 6, wherein, The sidelink discontinuous reception configuration is at least in part based on a discovery resource pool for the first discovery message or the second discovery message or both.

8. The device according to claim 6, wherein, The sidelink discontinuous reception configuration includes a group sidelink discontinuous reception configuration.

9. A device for wireless communication, comprising: one or more memories; and one or more processors, the one or more processors being coupled to the one or more memories and configured to: obtain sidelink discontinuous reception information from a user equipment (UE); and The output includes a message with a sidelink discontinuous reception configuration, the sidelink discontinuous reception configuration including an indication of a sidelink discontinuous reception mode for the UE, and the sidelink discontinuous reception mode for the UE being at least partially based on the sidelink discontinuous reception information.

10. The device according to claim 9, wherein, To send the message, the one or more processors are configured to: output to the UE a radio resource control reconfiguration message including the sidelink discontinuous reception configuration; and obtain a radio resource control reconfiguration complete message at least partially based on the radio resource control reconfiguration message.

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