DISCONTINUOUS RECEPTION FOR SIDELINK COMMUNICATIONS IN WIRELESS COMMUNICATIONS SYSTEMS

Methods, systems, and devices for wireless communication are described. A user equipment (UE) may transmit sidelink discontinuous reception (DRX) information to a base station while operating in a connected mode. In some examples, the UE may include the sidelink DRX information in UE-assistance information (UAI). The sidelink DRX information may include a preference of a DRX cycle, a DRX active duration, a DRX inactive duration, and the like, for 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.

INTRODUCTION

The following relates to wireless communications, and more specifically to managing sidelink communications in wireless communications systems.

A wireless multiple-access communications system may include one or more base stations or one or more network access nodes, each simultaneously supporting communication for multiple communication devices, which may be otherwise known as user equipment (UE). Some wireless communications systems may support sidelink communications between multiple communication devices. Examples of sidelink communications may include, but are not limited to, device-to-device (D2D) communications, vehicle-based communications, which may also be referred to as vehicle-to-everything (V2X) communications systems, vehicle-to-vehicle (V2V) communications systems, cellular V2X (C-V2X) communications systems, and the like.

SUMMARY

A method of wireless communication at a UE is described. The method may include transmitting sidelink DRX (DRX) information to a base station while 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.

An apparatus for wireless communication is described. The apparatus may include a processor, and memory coupled with the processor, the processor and memory configured to transmit sidelink DRX information to a base station while 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.

Another apparatus for wireless communication is described. The apparatus may include means for transmitting sidelink DRX information to a base station while 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.

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 transmit sidelink DRX information to a base station while 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.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for 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.

In some examples of the method, apparatuses, and non-transitory computer-readable medium 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.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for broadcasting a discovery request message during the active duration of the DRX cycle based on the sidelink DRX configuration, monitoring the sidelink channel to receive a discovery response message from the second UE during the active duration of the DRX cycle, and receiving the discovery response message from the second UE based on the monitoring, the discovery signal including the discovery response message.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for selecting the second UE for relay communications between the UE and the base station, or between the UE and a third UE, or both, based on the discovery signal, where the relay communications correspond to a layer2(L2) forwarding function or a layer3(L3) forwarding function.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for determining, based on the sidelink DRX configuration, a sidelink DRX pattern for monitoring the sidelink channel to receive the discovery signal from the second UE, the sidelink DRX pattern including the DRX cycle including the active duration and an inactive duration.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, 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.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for receiving a downlink signal from the base station using a cellular link based on the sidelink DRX configuration; or, and transmitting an uplink signal to the base station using the cellular link based on the sidelink DRX configuration.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for determining, based on the sidelink DRX configuration, a sidelink DRX pattern for receiving the downlink signal or transmitting the uplink signal, or both, the sidelink DRX pattern including a DRX cycle including an active duration and an inactive duration, where receiving the downlink signal or transmitting the uplink signal, or both, may be based on the sidelink DRX pattern.

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

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for transmitting an RRC reconfiguration complete message to the base station based on the RRC reconfiguration message, where operating according to the sidelink DRX configuration may be based on the RRC reconfiguration complete message.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for including the sidelink DRX information in UE-assistance information (UAI), transmitting the UAI including the sidelink DRX information to the base station while operating in the connected mode, where receiving the message including the sidelink DRX configuration may be based on the UAI.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for determining a single connected mode DRX cycle for sidelink communications or cellular communications, or both, based on the sidelink DRX configuration, and where operating according to the sidelink DRX configuration may be based on the single connected mode DRX cycle.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, 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 data traffic for the UE, or both, where the sidelink DRX information includes an indication of the DRX cycle.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for determining a value of an activity timer associated with a DRX cycle based on a relay service associated with a second UE or a QoS associated with data traffic for the UE, or both, where the sidelink DRX information includes an indication of the value of the activity timer associated with the DRX cycle.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for determining a value of an inactivity timer associated with a DRX cycle based on a relay service associated with a second UE or a QoS associated with data traffic for the UE, or both, where the sidelink DRX information includes an indication of the value of the inactivity timer associated with the DRX cycle.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for determining an offset between a beginning of a DRX cycle and a beginning 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 for the UE, or both, where the sidelink DRX information includes an indication of the offset.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for determining a first sidelink DRX pattern 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 pattern 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, where the first sidelink DRX pattern may be different from the second sidelink DRX pattern.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the sidelink DRX configuration includes a first indication of the first sidelink DRX pattern or a second indication of the second sidelink DRX pattern, or both.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the sidelink DRX configuration includes a connected mode DRX configuration.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the sidelink DRX configuration includes a sidelink DRX preference associated with a discovery procedure including a first model discovery procedure or a second model discovery procedure.

In some examples of the method, apparatuses, and non-transitory computer-readable medium 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.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the UE includes a remote UE and a second UE includes a rely UE between the remote UE and the base station.

A method of wireless communication at a UE is described. The method may include receiving a message including a group sidelink DRX configuration associated with a group of UEs while operating in an out-of-coverage mode, an idle mode, or an inactive mode, determining a temporal period to enable discontinuous monitoring of a sidelink channel based on the group sidelink DRX configuration, and monitoring the sidelink channel during the temporal period.

An apparatus for wireless communication is described. The apparatus may include a processor, and memory coupled with the processor, the processor and memory configured to receive a message including a group sidelink DRX configuration associated with a group of apparatuses while operating in an out-of-coverage mode, an idle mode, or an inactive mode, determine a temporal period to enable discontinuous monitoring of a sidelink channel based on the group sidelink DRX configuration, and monitor the sidelink channel during the temporal period.

Another apparatus for wireless communication is described. The apparatus may include means for receiving a message including a group sidelink DRX configuration associated with a group of apparatuses while operating in an out-of-coverage mode, an idle mode, or an inactive mode, determining a temporal period to enable discontinuous monitoring of a sidelink channel based on the group sidelink DRX configuration, and monitoring the sidelink channel during the temporal period.

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 receive a message including a group sidelink DRX configuration associated with a group of UEs while operating in an out-of-coverage mode, an idle mode, or an inactive mode, determine a temporal period to enable discontinuous monitoring of a sidelink channel based on the group sidelink DRX configuration, and monitor the sidelink channel during the temporal period.

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

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for enabling discontinuous monitoring of the sidelink channel based on the SIB or the RRC reconfiguration message.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for disabling a DRX mode based on a QoS associated with pending data traffic satisfying a QoS threshold.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the group sidelink DRX configuration includes a DRX periodicity common to the group of UEs.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the sidelink DRX configuration includes an active duration of a DRX cycle common to the group of UEs.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the sidelink DRX configuration includes a group offset duration between a beginning of a DRX cycle and an active duration of the DRX cycle, where the group offset duration may be common to the group of UEs.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the temporal period may be common to the group of UEs.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the UE may be grouped in the group of UEs based on a pathloss parameter.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the UE may be grouped in the group of UEs based on a QoS associated with data traffic of the UE.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for determining a UE-specific offset duration associated with an active duration of a DRX cycle based on the sidelink DRX configuration, where monitoring the sidelink channel includes.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the UE-specific offset duration may be based on a layer2(L2) identifier associated with the UE.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for enabling a DRX mode based on the message.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for enabling a DRX mode based on a QoS associated with pending data traffic satisfying a QoS threshold.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for enabling a DRX mode based on a power level of the UE satisfying a power level threshold.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for refraining from monitoring one or more resource pools during an inactive duration of a DRX cycle based on the group sidelink DRX configuration.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for refraining from 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 for the discovery signal.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, 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 traffic condition for the UE, where the inactive duration may be common to the group of UEs, where the inactive duration and the DRX cycle may be common to the group of UEs.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, 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 transmitting an uplink signal 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 may be common to the group of UEs.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for synchronizing with the group of UEs based on a synchronization signal received on a sidelink broadcast channel from at least one UE associated with the group of UEs.

A method of wireless communications 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 transmitting a discovery response message to a second UE during the active duration of the DRX cycle.

An apparatus for wireless communication is described. The apparatus may include a processor, and memory coupled with the processor, the processor and memory 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 transmit a discovery response message to a second UE during the active duration of the DRX cycle.

Another apparatus for wireless communication is described. The apparatus may include means for 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 transmitting a discovery response message to a second UE during the active duration of the DRX cycle.

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 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 transmit a discovery response message to a second UE during the active duration of the DRX cycle.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the sidelink DRX configuration may be 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.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for establishing a connection with the second UE to relay communications for the UE, where the relay communications correspond to a L2forwarding function or a L3forwarding function.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for transmitting a synchronization signal to the second UE on a sidelink broadcast channel, and synchronizing with the second UE based on the synchronization signal.

A method of wireless communications at a base station is described. The method may include receiving sidelink DRX information from a UE, determining a sidelink DRX pattern for the UE based on the sidelink DRX information, and transmitting a message including a sidelink DRX configuration including an indication of the sidelink DRX pattern for the UE.

An apparatus for wireless communication is described. The apparatus may include a processor, and memory coupled with the processor, the processor and memory configured to receive sidelink DRX information from a UE, determine a sidelink DRX pattern for the UE based on the sidelink DRX information, and transmit a message including a sidelink DRX configuration including an indication of the sidelink DRX pattern for the UE.

Another apparatus for wireless communication is described. The apparatus may include means for receiving sidelink DRX information from a UE, determining a sidelink DRX pattern for the UE based on the sidelink DRX information, and transmitting a message including a sidelink DRX configuration including an indication of the sidelink DRX pattern for the UE.

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 to receive sidelink DRX information from a UE, determine a sidelink DRX pattern for the UE based on the sidelink DRX information, and transmit a message including a sidelink DRX configuration including an indication of the sidelink DRX pattern for the UE.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, transmitting the message may include operations, features, means, or instructions for transmitting an RRC reconfiguration message including the sidelink DRX configuration to the UE.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for receiving an RRC reconfiguration complete message to the base station based on the RRC reconfiguration message.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for receiving UAI including the sidelink DRX information from the UE.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for determining the sidelink DRX pattern for the UE based on a resource pool configuration for the UE.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for determining a first sidelink DRX pattern associated with the sidelink DRX configuration for monitoring a sidelink channel for a discovery signal at the UE based on the sidelink DRX information, and determining a second sidelink DRX pattern associated with the 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 pattern may be different from the second sidelink DRX pattern.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the sidelink DRX configuration includes a connected mode DRX configuration.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the sidelink DRX configuration includes a sidelink DRX preference.

DETAILED DESCRIPTION

Wireless communications systems may include multiple communication devices such as UEs and base stations, which may provide wireless communication services to other UEs. For example, base stations may be next-generation NodeBs or giga-NodeBs (either of which may be referred to as a gNB) that may support multiple radio access technologies including 4G systems, such as LTE systems, as well as 5G systems, which may be referred to as NR systems. Some wireless communications systems may also support sidelink communications between multiple UEs. Examples of sidelink communications may include, but are not limited to, D2D communications, vehicle-based communications, which may also be referred to as V2X communications systems, V2V communications systems, etc. Some wireless communications systems may support relay operations to extend network coverage for UEs.

A UE may communicate directly with a network device (e.g., a network operator of a network (e.g., a 4G network, a 5G network)). Alternatively, the UE may communicate with the network device indirectly through another UE (also referred to as a relay UE). For example, a UE and a base station may be unable to communicate directly because the UE may be out-of-coverage for the base station, and hence the demand for a relay UE to relay communications between the UE and the base station. A UE that is out-of-coverage may be referred to herein as a remote UE. A remote UE may discover a relay UE based on discovery messages (also referred to as discovery signals) broadcasted from the relay UE and received at the remote UE as described herein. In another example, the remote UE may announce sidelink discovery solicitation messages to which a relay UE may respond. These discovery messages may include certain information that could be used by the remote UE or the relay UE, or both, to establish a sidelink (also referred to as a sidelink connection) used to relay transmissions to and from the base station, for example, to transmit and receive information related to services provided by the base station. A remote UE seeking to discover a relay UE to function as a relay may, in some cases, consume unnecessary power while monitoring for discovery messages. As a result, a battery life of the remote UE may be affected, which may also impact reliability and latency of receiving information related to the services at the remote UE.

Various aspects of the described techniques relate to configuring the remote UE to operate in a power saving mode (also referred to as a DRX mode) to reduce its power consumption when discovering and selecting a relay UE to function as a relay between the remote UE and the base station. While in the power saving mode, the remote UE may power-ON appropriate circuitry for some period to monitor a wireless channel for discovery messages from other UEs. After the period lapses, the remote UE may power-OFF for some other period. The power saving mode, including the periods for powering ON and OFF, may be specific for when the remote UE monitors for discovery messages for candidate relay UEs. Upon detecting a candidate relay UE, based on the discovery messages, the remote UE may select the candidate relay UE to function as a relay based on a sidelink quality satisfying a threshold or that the candidate relay UE can provide a connectivity service requested by the remote UE, or the like. The remote UE may evaluate the former condition by performing measurements on the discovery messages received from the candidate relay UE, and it checks the latter condition by referring to a field (e.g., a relay service code) included in the discovery messages provided by the candidate relay UE.

The periods associated with the power saving mode may be configured and provided by the base station based on information provided by the remote UE. For example, the remote UE may provide a DRX preference indicating a preference of one or more DRX parameters including a DRX cycle, an active duration of a DRX cycle, an inactive duration of a DRX cycle, a DRX cycle, a periodicity of a DRX cycle, an offset period associated with an active duration of a DRX cycle, a DRX inactivity timer, a DRX activity timer, a DRX retransmission timer, etc. In some cases, the remote UE may belong to a group of UEs, which may share a configuration (e.g., a sidelink DRX configuration) for the power saving mode. To avoid interferences between the UEs in the group, each UE may have an offset period for when to power-ON and power-OFF indicated in the configuration. Therefore, for sidelink communications, the UEs may experience power savings as a result of supporting relay selection and discovery according to a power saving mode (e.g., using a sidelink DRX configuration for sidelink communications, as well as relay monitoring and discovery).

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

Aspects of the disclosure are initially described in the context of wireless communications systems. Aspects of the disclosure are further illustrated by and described with reference to apparatus diagrams, system diagrams, and flowcharts that relate to managing DRX for sidelink communications for selecting a relay device in wireless communications systems.

The base stations105may communicate with the core network130, or with one another, or both. For example, the base stations105may interface with the core network130through one or more backhaul links120(e.g., via an S1, N2, N3, or other interface). The base stations105may communicate with one another over the backhaul links120(e.g., via an X2, Xn, or other interface) either directly (e.g., directly between base stations105), or indirectly (e.g., via core network130), or both. In some examples, the backhaul links120may be or include one or more wireless links. A UE115may communicate with the core network130through a communication link155. One or more of the base stations105described herein may include or may be referred to by a person having ordinary skill in the art as a base transceiver station, a radio base station, an access point, a radio transceiver, a NodeB, an eNodeB (eNB), a next-generation NodeB or a giga-NodeB (either of which may be referred to as a gNB), a Home NodeB, a Home eNodeB, or other suitable terminology.

A UE115may include or may be referred to as a mobile device, a wireless device, a remote device, a handheld device, or a subscriber device, or some other suitable terminology, where the “device” may also be referred to as a unit, a station, a terminal, or a client, among other examples. A UE115may also include or may be referred to as a personal electronic device such as a cellular phone, a personal digital assistant (PDA), a tablet computer, a laptop computer, or a personal computer. In some examples, a UE115may include or be referred to as a wireless local loop (WLL) station, an Internet of Things (IoT) device, an Internet of Everything (IoE) device, or a machine type communications (MTC) device, among other examples, which may be implemented in various objects such as appliances, or vehicles, meters, among other examples. The UEs115described herein may be able to communicate with various types of devices, such as other UEs115that may sometimes act as relays as well as the base stations105and the network equipment including macro eNBs or gNBs, small cell eNBs or gNBs, or relay base stations, among other examples, as shown inFIG.1.

A macro cell covers a relatively large geographic area (e.g., several kilometers in radius) and may allow unrestricted access by the UEs115with service subscriptions with the network provider supporting the macro cell. A small cell may be associated with a lower-powered base station105, as compared with a macro cell, and a small cell may operate in the same or different (e.g., licensed, unlicensed) frequency bands as macro cells. Small cells may provide unrestricted access to the UEs115with service subscriptions with the network provider or may provide restricted access to the UEs115having an association with the small cell (e.g., the UEs115in a closed subscriber group (CSG), the UEs115associated with users in a home or office). A base station105may support one or multiple cells and may also support communications over the one or more cells using one or multiple component carriers. 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 for different types of devices.

A UE115may operate in a DRX mode. In some examples, the UE115may operate in the DRX mode based at least in part on a DRX configuration. A DRX configuration may define one or more DRX parameters, for example an active duration of a DRX cycle, an inactive duration of a DRX cycle, a DRX cycle, a periodicity of a DRX cycle, an offset period associated with an active duration of a DRX cycle, a DRX inactivity timer, a DRX activity timer, a DRX retransmission timer, etc. A DRX cycle may include an active duration of the DRX cycle and an inactive duration of the DRX cycle may be defined by a time unit of slots or milliseconds (ms).

In some examples, a DRX configuration may be per MAC entity. In some other examples, a DRX configuration may be per frequency range (FR). For example, a DRX configuration may be defined for an FR1that may refer to frequency range between about 450 MHz and about 7.125 GHz or an FR2that may refer to a frequency range between about 24.25 GHz and about 52.6 GHz. The UE115may also be configured with a DRX configuration based on providing in UE-assistance information (UAI) a preferred C-DRX configuration including a long-DRX cycle, a short-DRX cycle, a DRX inactivity timer, a short DRX cycle timer, etc. In some examples, a UE115might not operate in a DRX mode (e.g., a DRX mode disabled) and to experience power saving the UE115may wake up based on a wakeup signal received from the base stations105.

The UEs115may include a UE communications manager101that may provide high reliability and low latency wireless communications by supporting sidelink DRX operations for relay discovery, selection, and reselection as described herein. The UE communications manager101may be an example of aspects of a UE communications manager as described inFIGS.8through11. Similarly, the base stations105may include a base station communications manager102that may provide sidelink DRX configurations as described herein. The base station communications manager102may be an example of aspects of a base station communications manager as described inFIGS.12through15.

FIG.2illustrates an example of a wireless communications system200in accordance with one or more aspects of the present disclosure. The wireless communications system200may implement aspects of the wireless communications system100. For example, the wireless communications system200may include a base station105-a, a UE115-a, a UE115-b, a UE115-c, and a UE115-d, which may be examples of a base station105and a UE115as described herein. The wireless communications system200may support multiple radio access technologies including 4G systems such as LTE systems, LTE-A systems, or LTE-A Pro systems, and 5G systems, which may be referred to as NR systems. The wireless communications system200may include features for improvements to power savings and, in some examples, may promote high reliability and low latency wireless communications, among other benefits.

The wireless communications system200may support sidelink communications between multiple UEs115over sidelink connections (also referred to as D2D connections). For instance, the UE115-aand the UE115-bmay perform sidelink communications over a sidelink connection205-a. The UE115-amay, additionally or alternatively, perform sidelink communications over a sidelink connection205-bwith the UE115-cor over a sidelink connection205-cwith the UE115-d. Similarly, the UE115-cand the UE115-dmay perform sidelink communication over a sidelink connection205-d. The sidelink connections205may correspond to a PC5 interface, which may facilitate sidelink communications between at least two UEs115without involving the base station105-a. The PC5 interface may also be a one-to-many communication interface (e.g., may be specified for group communications).

In the example ofFIG.2, a UE115may communicate directly with the base station105-aor may communicate indirectly with the base station105-a. For example, the UE115-amay communicate directly with the base station105-aover a cellular connection210, which may correspond to a Uu interface. The Uu interface may refer to an over-the-air interface for downlink transmissions, uplink transmissions, or both. The UE115-bmay communicate with the base station105-aindirectly through the UE115-a(also referred to as a relay UE115-a). For example, the UE115-band the base station105-amay be unable to communicate directly because the UE115-bmay be out-of-coverage for the base station105-a, and hence the demand for a relay UE to relay communications (e.g., control and/or data traffic) between the UE115-band the base station105-a.

The relay UE115-amay be configured by the base station105-afor relay services and, if configured, the relay UE115-amay be provisioned with a configuration that controls relay operations. To enable such network control, the relay UE115-amay indicate to the base station105-arelay capabilities during a connection procedure (e.g., an attach procedure). For example, the relay UE115-amay indicate resource requests for providing a relaying service and the base station105-amay configure the relay UE115-awith the requested resources. The base station105-amay control the relay services by configuring the relay UE115-awith conditions when to provide relay services to other UEs115in the wireless communications system200.

The base station105-amay configure a threshold, for example a reference signal received power (RSRP) threshold, a received signal received quality (RSRQ) threshold, or the like. The relay UE115-amay provide relay services (e.g., function as a relay node in the wireless communications system200) based on an RSRP or an RSRQ, or both, of a serving cell such as the base station105-asatisfying an RSRP threshold or an RSRQ threshold, or both. In other words, the relay UE115-amay provide relay services if an RSRP or an RSRQ, or both, associated with the cellular connection210(e.g., Uu link) satisfies the RSRP threshold or the RSRQ threshold, or both. Otherwise, the base station105-amay prevent the UE115-afrom functioning (e.g., providing relay services) as a relay node in the wireless communications system200.

The wireless communications system200may also provide other conditions for supporting relay discovery and selection using sidelink communications. For example, in the wireless communications system200, the UEs115may support relay discovery, selection, and reselection, or a combination thereof, using sidelink communications while operating in a standalone mode for sidelink-based UE-to-network and UE-to-UE relay. The wireless communications system200may provide relay UE and remote UE authorization. In some examples, the relay UE115-amay provide relay services (e.g., function as a relay node in the wireless communications system200) based on a quality of service (QoS) associated with data traffic between the base station105-aand the relay UE115-asatisfying a QoS threshold. In the wireless communications system200, the UEs115may provide relay services based on a service continuity, a security of a relayed connection (e.g., the sidelink connection205-aand/or the cellular connection210), or impact on user-plane protocol stack and control plane procedure (e.g., connection management of a relayed connection).

A UE115supporting sidelink communications my provide sidelink communications using a protocol stack as described herein. A remote UE115-bmay generate data traffic to be transmitted to the relay UE115-a. This user data traffic may be packetized at an IP layer in an IP packet. The IP packet then passes down to access stratum (AS) layers. The functions of the AS layers for sidelink communications are described as follows. A packet data convergence protocol (PDCP) layer of the AS layers may support header compression of a received IP service data unit to reduce a size of an IP packet header of the IP packet. The PDCP layer may establish a sidelink radio bearer (SLRB) to carry data traffic over a sidelink (e.g., the sidelink connection205-abetween the remote UE115-band the relay UE115-a). An RLC layer may be an unacknowledged mode (UM) radio link control (RLC) supported for the sidelink communication. The support of UM RLC for the sidelink communications may be dependent on delay-sensitive and error-tolerant traffic.

A MAC layer of the AS layers may perform logical channel prioritization by considering a priority of each sidelink logical channel corresponding to the SLRB. A MAC header may include a source ID and a destination ID field. A MAC layer at the relay UE115-amay use the destination ID for packet filtering. Each MAC protocol data unit may have one new transmission and up to three retransmissions so that the relay UE115-amay perform HARQ combining. A physical (PHY) layer of the AS layers may provide data transmission involving transmission of a physical control channel carrying sidelink control information (SCI), and a physical data channel. For each new transmission, the remote UE115-bmay transmit SCI that indicates a layer-1destination ID, modulation and coding scheme (MCS), and time—frequency location of the data traffic. Then, the remote UE115-bmay transmit data traffic on the physical data channel that immediately follows the control channel.

A UE115that is out of coverage may be referred to herein as a remote UE115. In the example ofFIG.2, the UE115-bmay be referred to as a remote UE115-b. The remote UE115-bmay discover the relay UE115-abased on discovery messages broadcasted from the remote UE115-bor discovery message received from the rely UE115-a. These messages may include certain information (e.g., synchronization information, service information, etc.) that could be used by the remote UE115-bor the rely UE115-a, or both, to establish the sidelink connection205-aused to relay transmissions to and from the base station105-a, for example, to transmit and receive information related to services provided by the base station105-a. As described herein, a rely UE may be in a connected mode. That is, the rely UE may have a connection to a network (e.g., the base station105-a). A remote UE as described herein may operate in a connected mode, an idle mode, an inactive mode, or a out-of-coverage mode, or any combination thereof. Accordingly, a sidelink DRX for the remote UE115-bmight have to be synchronized among all remote UEs115and relay UEs115. Relay UEs115may always be connected and thereby synchronized with the base station105-a.

The remote UE115-bto begin with might not be connected to any relay UEs in the wireless communications system200(e.g., a PC5 unicast link is not established between the remote UE115-band the relay UE115-a). The remote UE115-bmay identify a presence of at least one suitable relay UE115to request relay service in its proximity based on the discovery messages. To enable identification, the relay UE115-amay announce its presence by transmitting sidelink discovery messages periodically, and/or the remote UE115-bmay announce sidelink discovery solicitation messages, expecting the relay UE115-a, for example nearby to respond. Accordingly, for relay selection, the remote UE115-bmay might not be connected to any relay UE. The remote UE115-bmay discover all relay UEs in the wireless communications system200that has a sidelink RSRP, RSRQ, QoS, etc. satisfying a threshold. For relay reselection, the remote UE115-bmay be connected at least one relay UE (e.g., the relay UE115-a). When a sidelink RSRP, RSRQ, QoS, etc. does not satisfy a threshold, the remote UE115-bmay discover other relay UEs that satisfy the threshold. For example, a remote UE may discover multiple candidate relay UEs and select one relay UE that has the highest sidelink RSRP, RSRQ, QoS, etc.

The remote UE115-bseeking to discover a relay UE, such as the relay UE115-ato function as a relay may, in some cases, consume considerable power while monitoring for discovery messages. The relay UE115-amay also consume considerable power while transmitting discovery messages. As a result, a battery life of the relay UE115-aand the remote UE115-bmay be affected, which may also impact reliability and latency of receiving information related to the services at the remote UE115-b. In other words, without sidelink DRX operations, the relay UE115-aand the remote UE115-bmay keep its receiver and/or transmitter continuously active to monitor and receive relay discovery messages or transmit relay discover solicitation messages in the wireless communications system200. Various aspects of the described techniques relate to configuring the remote UE115-bto operate in a power saving mode (also referred to as a DRX mode) to reduce its power consumption when discovering and selecting a relay UE115to function as a relay between the remote UE115-band the base station105-aor other device in the wireless communications system200.

While in the DRX mode, the remote UE115-bmay power-ON appropriate circuitry for some period (e.g., an active duration of a DRX cycle) to monitor a wireless channel for discovery messages from other UEs115. After the period lapses, the remote UE115-bmay power-OFF for some other period (e.g., an inactive duration of a DRX cycle). The DRX mode including the periods for powering ON and OFF may be specific for when the remote UE115-bmonitors for discovery messages. Once the remote UE115-bdetects a candidate relay UE (e.g., the relay UE115-a) based on the discovery messages, the remote UE115-bmay select the candidate relay to function as a relay based on a sidelink quality satisfying a threshold or that the candidate relay can provide a connectivity service requested by the remote UE115-aas described herein.

The remote UE115-bmay evaluate the former condition by performing measurements on the discovery messages received from the candidate relay UE115-a, and it checks the latter condition by referring to a field (e.g., a relay service code) included in the discovery messages provided by the candidate relay UE115-a. The periods associated with the DRX mode may be configured and provided by the base station105-abased on information provided by the remote UE115-b. In some cases, the remote UE115-bmay belong to a group of UEs115, which may share a sidelink configuration (e.g., sidelink DRX information) for the DRX mode. The group of UEs115may include the remote UE115-b, the UE115-c, and the UE115-d. To avoid interferences between the UEs115in the group, each UE115may have an offset period for when to power-ON and power-OFF indicated in the sidelink DRX configuration as described herein.

The sidelink DRX configuration may be applicable for broadcast communications, groupcast communications, and unicast communications. The sidelink DRX configuration may define an active duration and an inactive duration of a DRX cycle. In some examples, the sidelink DRX configuration may provide a mechanism to align sidelink DRX active durations among the UEs115communicating with each other. In some other examples, the sidelink DRX configuration may provide a mechanism to align sidelink DRX active durations with Uu DRX active durations for an in-coverage UE115.

The remote UE115-bmay while in a connected mode report its sidelink DRX preference to the base station105-a. For example, the remote115-bmay at one time instance be within coverage of the base station105-aand may report sidelink DRX preference to the base station105-a. The base station105-amay configure the remote UE115-bwith the sidelink DRX configuration, which may be a UE-specific C-DRX configuration for both cellular reception (e.g., Uu reception) and relay discovery message monitoring. Alternatively, the remote UE115-bmay while in an idle mode, an inactive mode, an out of coverage mode, or any combination thereof, may support a remote UE group common sidelink DRX configuration. The remote UE group common sidelink DRX configuration may be broadcast in a system information block (SIB) and in a pre-configuration message (e.g., an RRC pre-configuration message).

Once the remote UE115-bdetects a relay UE candidate, such as the relay UE115-a, it selects the relay UE115-abased on satisfying one or more criteria. For example, the remote UE115-bmay select the relay UE115-afor relay services based on a sidelink quality of the sidelink connection205-asatisfying a threshold. Additionally or alternatively, the remote UE115-bmay select the relay UE115-afor relay services based on the relay UE115-asupporting a relay or connectivity service requested by the remote UE115-b. The remote UE115-bmay evaluate one or both criteria. During relay discovery, the remote UE115-bmay obtain a UE identifier (ID) of the relay UE115-ato be used for sidelink transmission and reception of relayed data traffic.

In some examples, if DRX is configured, the relay UE115-amay transmit a sidelink broadcast channel (SL-BCH) for synchronization of the remote UE115-b. Synchronization for sidelink communications may include the relay UE115-atransmitting synchronization information over the sidelink connection205-ato the remote UE115-b, and then, the remote UE115-bbecoming synchronized. The synchronization information may include 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 communications including the sidelink synchronization signal, the rely UE115-ain coverage uses network synchronization that is related to uplink/downlink synchronization. If the remote UE115-bthat is out of coverage detects suitable synchronization information transmitted by the relay UE115-a, the remote UE115-bmay use the detected synchronization information.

The remote UE115-bmay selectively (e.g., conditionally) enable or disable a sidelink DRX mode or a sidelink DRX configuration. In some examples, the remote UE115-bmay by default enable sidelink DRX if configured in SIB or an RRC pre-configuration message. In some other examples, the remote UE115-bmay by default enable sidelink DRX based at least in part on a QoS of pending data traffic at the remote UE115-b. For example, the remote UE115-bmay enable sidelink DRX if a lowest QoS of all pending data traffics is higher than a QoS threshold. Otherwise, the remote UE115-bmay disable sidelink DRX. Thus, when the remote UE115-bhas urgent data traffic, it is allowed to monitor all discovery messages, in order to reduce a latency caused by relay selection. In other examples, the remote UE115-bmay enable sidelink DRX based on a battery status (e.g., a battery level, a battery percentage) of the remote UE115-b. Thus, the remote UE115-bmay enable sidelink DRX if a battery of the remote UE115-bis lower than a battery threshold.

The relay UE115-amay relay traffic between the sidelink connection205-a(e.g., a PC5 interface) and the cellular connection210(e.g., a Uu interface) by performing traffic mapping. For example, the rely UE115-amay map uplink/downlink bearers on sidelink bearers and vice versa, and this mapping may be used for proper packet routing and quality-of-service (QoS) treatment. For sidelink to uplink mapping, which occurs when the rely UE115-areceives traffic from the remote UE115-bover the sidelink connection205-a, the rely UE115-auses uplink traffic flow templates to select uplink bearers to carry the received traffic over uplink. For downlink to sidelink mapping, which occurs when the rely UE115-areceives traffic from the base station105-aover the cellular connection210, it identifies whether the packet has to be relayed, by referring to the destination address of the packet. The rely UE115-athen assigns a priority value (also referred to a ProSe per packet priority (PPPP)) to the received packet to be relayed.

The priority assignment may be based on the mapping information representing the association between the QoS class identifier (QCI) values of downlink bearers and the priority values. The QCI-to-priority mapping information may be provisioned to the rely UE115-aby the base station105-a. In some examples, the relay UE115-amay distribute its discovery message transmissions though applying random resource transmission pool selection (e.g., mode2), or the base station105-amay distributivity schedule (e.g., model) within a DRX common active duration. This may avoid relay UEs115with a same relay service code from waking up at a same time. The relay UE115-amay thus send more frequent discovery messages depending on its relay capability (e.g., supports high QoS bearer with the base station105-aand/or the remote UE115-b).

The data traffic may be unicast traffic or multicast traffic. When the relay UE115-aprovides relay service for unicast traffic, it establishes one-to-one sidelink connection with the remote UE115-a. The PC5 signaling protocol is introduced to provide direct connection management functions such as direct link setup/release, security parameter control, and IP address allocation. In addition, this protocol can support transacting the request from the remote UE115-bfor multicast traffic relaying. While establishing the sidelink connection, the remote UE115-bmay be allocated an IP address to be used for relayed traffic. Once the relay UE115-aestablishes the sidelink connection205-awith the remote UE115-b, it reports to the base station105-athe information on the remote UE115-bcontext such as the EPS bearer ID used for relaying, remote UE ID, and optionally, the IP address. This remote UE115-acontext is forwarded to the base station105-a, which utilizes this information for traffic management including mapping of relay traffic to the EPS bearer used for relaying.

FIG.3illustrates an example of a process flow300in accordance with one or more aspects of the present disclosure. The process flow300may implement aspects of the wireless communications system100and200described with reference toFIGS.1and2, respectively. The process flow300may be based on a configuration by a base station105-bor a UE115-e, and implemented by the UE115-eand may promote power saving for the UE115-eby supporting sidelink DRX operations. The process flow300may also be based on a configuration by the base station105-bor the UE115-e, and implemented by the UE115-eto promote high reliability and low latency wireless communications by relaying the wireless communications using sidelink communications, among other benefits.

The base station105-band the UE115-emay be examples of a base station105and a UE115, as described with reference toFIGS.1and2. In the following description of the process flow300, the operations between the base station105-band the UE115-emay be transmitted in a different order than the example order shown, or the operations performed by the base station105-band the UE115-emay be performed in different orders or at different times. Some operations may also be omitted from the process flow300, and other operations may be added to the process flow300.

In the example ofFIG.3, the UE115-emay be operating in a connected mode. That is, the UE115-bmay to begin with having a direct connection (e.g., via a Uu interface) with the base station105-b. The UE115-e, in the example ofFIG.3, may to begin with not be connected to a relay node (e.g., a relay UE) in the wireless communications system. However, later the UE115-emay be out-of-coverage from the base station105-band may continue wireless communications with the base station105-busing a relay UE as described herein. Various aspects of the process flow300relate to configuring the UE115-eto operate in a power saving mode (also referred to as a sidelink DRX mode or a C-DRX mode) to reduce its power consumption when monitoring a wireless communications system for discovering and selecting a relay UE to function as a relay between the UE115-eand the base station105-b.

At305, the UE115-emay transmit sidelink DRX information to the base station105-b, for example, via a Uu interface. The UE115-emay transmit the sidelink DRX information in UE-assistance information (UAI). The sidelink DRX information may indicate a DRX preference, which may include a DRX cycle, an active duration of a DRX cycle, an offset period prior to the active duration of the DRX cycle, a DRX inactivity timer, a DRX retransmission timer, etc. The UE115-bmay thereby report its preference for sidelink DRX operations to the base station105-bvia the sidelink DRX information. The UE115-emay determine the DRX preference based at least in part on a relay service or QoS requirements of pending data traffic at the UE115-e, or both.

At310, the base station105-bmay determine a sidelink DRX configuration, for example, based on the received sidelink DRX information from the UE115-e. The sidelink DRX configuration may define a DRX pattern including an active duration of a DRX cycle and an inactive duration of a DRX cycle. The base station105-bmay configure a UE-specific DRX pattern for the UE115-evia Uu RRC messages. That is, the base station105-bmay configure a single DRX pattern for the UE115-bfor both cellular communications (e.g., Uu reception/transmission) and relay discovery monitoring and selection (e.g., via PC5 interface). In some examples, the base station105-bmay determine the sidelink DRX configuration or adjust the sidelink DRX configuration via RRC messages to modify the sidelink DRX configuration. Because the base station105-amay know a discovery resource pool configuration of the UE115-e, it can modify or configure the sidelink DRX configuration (e.g., a C-DRX) to account for overlap with the discovery resource pool configuration during a DRX cycle (e.g., a C-DRX ON periods).

At315, the base station105-bmay transmit an RRC reconfiguration message including the sidelink DRX configuration to the UE115-e. At320, the UE115-emay transmit an RRC reconfiguration complete message to the base station105-e. Additionally or alternatively, the base station105-bmay, in some examples, determine multiple DRX patterns (e.g., multiple C-DRX patterns) for the UE115-e. One DRX pattern may be for Uu reception and another DRX pattern may be for relay discovery monitoring. The base station105-bmay transmit the multiple DRX patterns in a single RRC reconfiguration message or separate RRC reconfiguration messages.

FIG.4illustrates an example of a timeline400in accordance with one or more aspects of the present disclosure. The timeline400may implement aspects of the wireless communications system100and200described with reference toFIGS.1and2, respectively. The timeline400may be based on a configuration by a base station105or a UE115, and implemented by the UE115to decrease power consumption for the UE115by supporting sidelink DRX operations. The timeline400may also be based on a configuration by the base station105or the UE115, and implemented by the UE115to promote high reliability and low latency wireless communications in a wireless communications system, among other benefits.

With reference to the timeline400, a relay UE115-for a remote UE115-g, or both, as described herein may operate according to a sidelink DRX configuration. The sidelink DRX configuration may define a DRX cycle405, which may include an active DRX duration410and an inactive DRX duration415. During the active DRX duration410, the relay UE115-fmay broadcast one or more discovery messages420over a sidelink channel. The remote UE115-gmay monitor a discovery resource pool425for the one or more broadcasted discovery messages420during the active DRX duration410.

A resource pool may be a reception resource pool or a transmission resource pool, or a combination thereof. These may be either signaled by a base station105for an in coverage case, or preconfigured for an out-of-coverage case. In the example ofFIG.4, the discovery resource pool425may be a reception resource pool. The discovery resource pool425may be a set of time and frequency resources assigned to the remote UE115-gfor sidelink operations, and more specifically for monitoring the discovery messages420.

The relay UE115-fmay also support cellular communications (e.g., via Uu interface) during the inactive DRX duration415of the DRX cycle405. For example, the relay UE115-fmay support cellular (Uu interface) transmissions and receptions (e.g., uplink/downlink messages430) to and from a base station105via a Uu interface. As illustrated inFIG.4, the remote UE115-gmight not perform any operations (e.g., channel monitoring for discovery messages, etc.) during the inactive DRX duration415of the DRX cycle405. The remote UE115-gmay thereby experience added power savings for relay discovery monitoring by disabling monitoring for the one or more discovery messages420during the inactive DRX duration415of the DRX cycle405.

FIG.5illustrates an example of a timeline500in accordance with one or more aspects of the present disclosure. The timeline500may implement aspects of the wireless communications system100and200described with reference toFIGS.1and2, respectively. The timeline500may be based on a configuration by a base station105or a UE115, and implemented by the UE115to decrease power consumption for the UE115by supporting sidelink DRX operations. The timeline500may also be based on a configuration by the base station105or the UE115, and implemented by the UE115to promote high reliability and low latency wireless communications in a wireless communications system, among other benefits.

With reference to the timeline500, one or more of the remote UEs115may receive a common sidelink DRX configurations in a system information message (e.g., a SIB) or an RRC message (e.g., an RRC reconfiguration message). For example, a base station105may broadcast the system information message (e.g., a SIB) or the RRC message (e.g., an RRC reconfiguration message) to one or more of the remote UEs115. One or more of the remote UEs115might not have a PC5 unicast link with a relay UE established, and one or more of the remote UEs115may be operating in an idle mode, an inactive mode, or an out-of-coverage mode, or a combination thereof. As such, one or more of the remote UEs115may be configured with a common sidelink DRX configurations for power saving when monitoring for discovery messages from a candidate relay UE.

For example, a remote UE115-hand a remote UE115-ias described herein may operate according to a common sidelink DRX configuration. The remote UE115-hand the remote UE115-imay be grouped into a same group of UEs based at least in part on a pathloss parameter to a base station105for each of the remote UE115-hand the remote UE115-ior a QoS of pending data traffic for each of the remote UE115-hand the remote UE115-i, or both. The common sidelink DRX configuration may define a DRX cycle505, which may include an active DRX duration510and an inactive DRX duration515. The DRX cycle505may be a common DRX cycle for the remote UE115-hand the remote UE115-i. As such, the active DRX duration510may be a common active DRX duration for the remote UE115-hand the remote UE115-i. Likewise, the inactive DRX duration515may be a common inactive DRX duration for the remote UE115-hand the remote UE115-i.

Alternatively, a remote UE115-j, as described herein, may operate according to a common sidelink DRX configuration different from the common sidelink DRX configuration associated with the remote UE115-hand the remote UE115-i. This common sidelink DRX configuration may define a DRX cycle520, which may include an active DRX duration525and an inactive DRX duration530. To avoid interference between the different groups of UEs115, the common sidelink DRX configuration may include different group common DRX periodicity, different group common active DRX durations, different group common DRX offset periods, different monitoring durations (e.g., a duration length may be group common but without offset), etc. That is, the remote UEs115belonging to different groups of UEs may perform operations (e.g., monitoring a sidelink channel for discovery messages) based on different sidelink DRX configurations.

In the example ofFIG.5, the active DRX duration510associated with the DRX cycle505may begin at tnand the active DRX duration525associated with the DRX cycle520may begin at tn. However, the active DRX duration510may end at tn+2while the active DRX duration525ends at tn+1. The inactive DRX duration515associated with the DRX cycle505may begin at tn+2while the inactive DRX duration530associated with the DRX cycle520may begin at tn+1. In the example ofFIG.5, both the inactive DRX duration515associated with the DRX cycle505and the inactive DRX duration530associated with the DRX cycle520may end at tn+3. The active DRX durations and inactive DRX durations may thus have different lengths for the different sidelink DRX configurations to avoid interference, as well as to provide opportunity for the remote UEs115to monitor for discovery messages. In addition, the remote UEs115may experience added power savings for relay discovery monitoring by disabling monitoring for discovery messages during the inactive DRX durations of the DRX cycles.

FIG.6illustrates an example of a timeline600in accordance with one or more aspects of the present disclosure. The timeline600may implement aspects of the wireless communications system100and200described with reference toFIGS.1and2, respectively. The timeline600may be based on a configuration by a base station105or a UE115, and implemented by the UE115to decrease power consumption for the UE115by supporting sidelink DRX operations. The timeline600may also be based on a configuration by the base station105or the UE115, and implemented by the UE115to promote high reliability and low latency wireless communications in a wireless communications system, among other benefits.

With reference to the timeline600, one or more of the remote UEs115may receive a common sidelink DRX configurations in a system information message (e.g., a SIB) or an RRC message (e.g., an RRC reconfiguration message). For example, a base station105may broadcast the system information message (e.g., a SIB) or the RRC message (e.g., an RRC reconfiguration message) to one or more of the remote UEs115. A remote UE115-land a remote UE115-mas described herein may operate according to a common sidelink DRX configuration. The remote UE115-land the remote UE115-mmay be grouped into a same group of UEs based at least in part on one or more parameters (e.g., a pathloss, a QoS of pending data traffic, etc.) as described herein. 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 a first model discovery procedure (e.g., announcement messages) or a second model discovery procedure (e.g., sonication and response messages).

The common sidelink DRX configuration may define a DRX cycle605, which may include an active DRX duration610and an inactive DRX duration615. The DRX cycle605may be a common DRX cycle for the remote UE115-land the remote UE115-m. As such, the active DRX duration610may be a common active DRX duration for the remote UE115-land the remote UE115-m. Likewise, the inactive DRX duration615may be a common inactive DRX duration for the remote UE115-land the remote UE115-m. To avoid interference between the remote UE115-land the remote UE115-mbelonging to a same group of UEs, the common sidelink DRX configuration may define a monitoring duration for each of the remote UE115-land the remote UE115-m, as well as an offset duration for one or both of the remote UE115-land the remote UE115-m. That is, to avoid waking up at the same time, the different UEs115-l, UE115-mmay have UE-specific DRX monitoring offsets via a random offset or a mapping with remote UE source L2ID as input (e.g., similar to paging PO calculation).

The remote UE115-lmay monitor a sidelink channel for one or more discovery messages620from a relay UE115-kduring a monitor duration630of the active DRX duration610associated with the DRX cycle605. The monitor duration630may begin at tn. Similarly, the remote UE115-mmay monitor a sidelink channel for one or more discovery messages620from the relay UE115-kduring a monitor duration635of the active DRX duration610associated with the DRX cycle605. The monitor duration630may begin at tn+1and end at tn+2, for example when the inactive DRX duration615begins. As such, each of the remote UE115-land the remote UE115-mmay have a portion of the active DRX duration allocated to monitor for discovery messages from the relay UE115-k. Additionally, the monitor duration635may begin after an offset duration640that spans from tnto tn+1. Thus, the remote UEs115may perform operations (e.g., monitoring a sidelink channel for discovery messages) based on different monitor durations indicated in the sidelink DRX configuration.

The remote UE115-lmay be configured to stop monitoring all reception resource pools outside the monitoring duration630. Likewise, the remote UE115-mmay be configured to stop monitoring all reception resource pools outside the monitoring duration635. The remote UE115-lmay be configured to stop monitoring all reception resource discovery pools if separate discovery and common pools are configured for the remote UEs115. Similarly, the remote UE115-mmay be configured to stop monitoring all reception resource discovery pools if separate discovery and common pools are configured for the remote UEs115. This may be suitable for the case where the UEs115have another PC5 unicast link setup for normal PC5 operation. A power consumption difference: discovery is groupcast and broadcast and takes max transmit power, while common message can use open and close loop power control. The discovery messages may be periodic and the UEs115may adapt to a DRX pattern, while common messages may be bursty. The remote UEs115-l,115-mmay determine to stop monitoring all reception resource pools including reception resource discovery pools outside the monitoring durations630,635based on an indication in a SIB or an RRC pre-configuration message.

The relay UE115-kmay also support cellular communications (e.g., via Uu interface) during the inactive DRX duration615of the DRX cycle605. For example, the relay UE115-kmay support cellular (Uu interface) transmissions and receptions (e.g., uplink/downlink messages625) to and from a base station105via a Uu interface. As illustrated inFIG.6, the remote UEs115-l, UE115-mmight not perform any operations (e.g., channel monitoring for discovery messages, etc.) during the inactive DRX duration615of the DRX cycle605. The remote UEs115-l,115-mmay thereby experience added power savings for relay discovery monitoring by disabling monitoring for the one or more discovery messages620during the inactive DRX duration615of the DRX cycle605. The inactive DRX duration615of the DRX cycle605may also provide power savings for the relay UE115-kby avoiding sending discovery messages during the inactive DRX duration615and performing other wireless operations (e.g., uplink/downlink transmission/reception). That is, the relay UE115-kmay perform discontinuous transmission (i.e. turn OFF its transmitter) because it knows the DRX cycle605of the remote UEs115-l,115-m. In some examples, the relay UE115-kmay transmit some relay discovery message within a DRX common inactive duration, for a remote UE115with pending urgent data traffic. The relay UE115may alternatively perform Uu transmission/reception within a DRX common inactive duration.

FIG.7illustrates an example of a timeline700in accordance with one or more aspects of the present disclosure. The timeline700may implement aspects of the wireless communications system100and200described with reference toFIGS.1and2, respectively. The timeline700may be based on a configuration by a base station105or a UE115, and implemented by the UE115to decrease power consumption for the UE115by supporting sidelink DRX operations. The timeline700may also be based on a configuration by the base station105or the UE115, and implemented by the UE115to promote high reliability and low latency wireless communications in a wireless communications system, among other benefits. In the example ofFIG.7, a single group of UEs115may include one or more relay UEs115and a remote UE. The group of UEs may share a same active DRX duration of a DRX cycle. The remote UE's monitoring window may be the same as a DRX common ON duration.

With reference to the timeline700, a relay UE115-n, a relay UE115-o, a relay UE115-por a remote UE115-q, or any combination thereof, as described herein may operate according to a sidelink DRX configuration. The sidelink DRX configuration may define a DRX cycle705, which may include one or more active DRX durations710and an inactive DRX duration715. In some examples, during the active DRX duration710, the relay UE115-nmay broadcast one or more discovery messages720over a sidelink channel. In some other examples, during the active DRX duration710, the relay UE115-omay broadcast one or more discovery messages725over a sidelink channel. In other examples, the relay UE115-pmay broadcast one or more discovery messages730over a sidelink channel. One or more of the relay UE115-n, the relay UE115-o, and the relay UE115-pmay distribute the discovery message transmissions though applying random resource transmission pool selection (e.g., mode2), or a base station105may distributivity schedule (e.g., model) the discovery message transmissions for the relay UEs115. This may avoid the relay UEs115with a same relay service code from waking up at a same time and causing interference to each other.

The remote UE115-qmay monitor a discovery resource pool for the one or more broadcasted discovery messages720,725, and730during the active DRX duration410. A resource pool may be a reception resource pool or a transmission resource pool, or a combination thereof. These may be either signaled by a base station105for an in coverage case, or preconfigured for an out-of-coverage case. In the example ofFIG.7, the remote UE115-qmay enable resource pool monitoring740during the active DRX duration710, and disable the resource pool monitoring745during the inactive DRX duration715. The discovery resource pool425may be a reception resource pool. The discovery resource pools as illustrated inFIG.7may be a set of time and frequency resources assigned to the remote UE115-qfor sidelink operations, and more specifically for monitoring one or more sidelink channels for the one or more discovery messages720,725, and730.

As illustrated inFIG.7, the remote UE115-qmight not perform any operations (e.g., channel monitoring for discovery messages, etc.) during the inactive DRX duration715of the DRX cycle705. The remote UE115-qmay thereby experience added power savings for relay discovery monitoring by disabling monitoring for the one or more discovery messages720,725, and730during the inactive DRX duration715of the DRX cycle705. One or more of the relay UE115-n, the relay UE115-o, and the relay UE115-pmay also support cellular communications (e.g., via Uu interface) during the inactive DRX duration715of the DRX cycle705. For example, the relay UE115-pmay support cellular (Uu interface) transmissions and receptions (e.g., uplink/downlink messages735) to and from a base station105via a Uu interface. One or more of the relay UE115-n, the relay UE115-o, and the relay UE115-pmay also experience power savings by avoiding sending discovery messages during the inactive DRX duration715and performing other wireless operations (e.g., uplink/downlink transmission/reception.

The receiver810may 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 communications in wireless communications systems, etc.). Information may be passed on to other components of the device805. The receiver810may be an example of aspects of the transceiver1120described with reference toFIG.11. The receiver810may utilize a single antenna or a set of antennas.

The UE communications manager815may transmit sidelink DRX information to a base station while 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.

The UE communications manager815may also receive a message including a group sidelink DRX configuration associated with a group of UEs while operating in an out-of-coverage mode, an idle mode, or an inactive mode, determine a temporal period to enable discontinuous monitoring of a sidelink channel based on the group sidelink DRX configuration, and monitor the sidelink channel during the temporal period.

The UE communications manager815may also 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 transmit a discovery response message to a second UE during the active duration of the DRX cycle. The UE communications manager815may be an example of aspects of the UE communications manager1110described herein.

The transmitter820may transmit signals generated by other components of the device805. In some examples, the transmitter820may be collocated with a receiver810in a transceiver module. For example, the transmitter820may be an example of aspects of the transceiver1120described with reference toFIG.11. The transmitter820may utilize a single antenna or a set of antennas.

FIG.9shows a block diagram900of a device905in accordance with one or more aspects of the present disclosure. The device905may be an example of aspects of a device805, or a UE115as described herein. The device905may include a receiver910, a UE communications manager915, and a transmitter940. The device905may also include a processor. Each of these components may be in communication with one another (e.g., via one or more buses).

The UE communications manager915may be an example of aspects of the UE communications manager815as described herein. The UE communications manager915may include a sidelink information component920, a sidelink configuration component925, a mode component930, and a discover component935. The UE communications manager915may be an example of aspects of the UE communications manager1110described herein.

The sidelink information component920may transmit sidelink DRX information to a base station while operating in a connected mode. The sidelink configuration component925may receive a message including a sidelink DRX configuration from the base station based on the sidelink DRX information. The mode component930may operate according to the sidelink DRX configuration.

The sidelink configuration component925may receive a message including a group sidelink DRX configuration associated with a group of UEs while operating in an out-of-coverage mode, an idle mode, or an inactive mode. The mode component930may determine a temporal period to enable discontinuous monitoring of a sidelink channel based on the group sidelink DRX configuration and monitor the sidelink channel during the temporal period.

The sidelink configuration component925may determine a DRX cycle based on a sidelink DRX configuration, the DRX cycle including an active duration and an inactive duration. The discover component935may receive a discovery request message from a second UE during the active duration of the DRX cycle and transmit a discovery response message to a second UE during the active duration of the DRX cycle.

The transmitter940may transmit signals generated by other components of the device905. In some examples, the transmitter940may be collocated with a receiver910in a transceiver module. For example, the transmitter940may be an example of aspects of the transceiver1120described with reference toFIG.11. The transmitter940may utilize a single antenna or a set of antennas.

FIG.10shows a block diagram1000of a UE communications manager1005in accordance with one or more aspects of the present disclosure. The UE communications manager1005may be an example of aspects of a UE communications manager815, a UE communications manager915, or a UE communications manager1110described herein. The UE communications manager1005may include a sidelink information component1010, a sidelink configuration component1015, a mode component1020, a discover component1025, a relay component1030, a network component1035, a message component1040, a resource pool component1045, a synchronization component1050, and a sidelink component1055. Each of these modules may communicate, directly or indirectly, with one another (e.g., via one or more buses).

The sidelink information component1010may transmit sidelink DRX information to a base station while operating in a connected mode. In some examples, the sidelink information component1010may include the sidelink DRX information in UAI. In some examples, the sidelink information component1010may transmit the UAI including the sidelink DRX information to the base station while operating in the connected mode, where receiving the message including the sidelink DRX configuration is based on the UAI.

The sidelink configuration component1015may receive a message including a sidelink DRX configuration from the base station based on the sidelink DRX information. In some examples, the sidelink configuration component1015may receive a message including a group sidelink DRX configuration associated with a group of UEs while operating in an out-of-coverage mode, an idle mode, or an inactive mode. In some examples, the sidelink configuration component1015may determine a DRX cycle based on a sidelink DRX configuration, the DRX cycle including an active duration and an inactive duration. In some examples, the sidelink configuration component1015may receive a SIB or an RRC reconfiguration message including the group sidelink DRX configuration. In some examples, the sidelink configuration component1015may enable discontinuous monitoring of the sidelink channel based on the SIB or the RRC reconfiguration message.

In some examples, the sidelink configuration component1015may disable a DRX mode based on a QoS associated with pending data traffic satisfying a QoS threshold. 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 procedure including a first model discovery procedure or a second model discovery procedure. In some cases, 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. In some cases, the UE includes a remote UE and a second UE includes a rely UE between the remote UE and the base station. In some cases, the group sidelink DRX configuration includes a DRX periodicity common to the group of UEs.

In some cases, the sidelink DRX configuration includes an active duration of a DRX cycle common to the group of UEs. In some cases, the sidelink DRX configuration includes a group offset duration between a beginning of a DRX cycle and an active duration of the DRX cycle, where the group offset duration is common to the group of UEs. In some cases, the UE is grouped in the group of UEs based on a pathloss parameter. In some cases, the UE is grouped in the group of UEs based on a QoS associated with data traffic of the UE. In some cases, the sidelink DRX configuration is 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.

The mode component1020may operate according to the sidelink DRX configuration. In some examples, the mode component1020may determine a temporal period to enable discontinuous monitoring of a sidelink channel based on the group sidelink DRX configuration. In some examples, the mode component1020may monitor the sidelink channel during the temporal period. In some examples, the mode component1020may determine a single connected mode DRX cycle for sidelink communications or cellular communications, or both, based on the sidelink DRX configuration. In some examples, the mode component1020may where operating according to the sidelink DRX configuration is based on the single connected mode DRX cycle. In some examples, determining a DRX cycle based on a relay service associated with a second UE or a QoS associated with data traffic for the UE, or both, where the sidelink DRX information includes an indication of the DRX cycle.

In some examples, the mode component1020may determine a value of an activity timer associated with a DRX cycle based on a relay service associated with a second UE or a QoS associated with data traffic for the UE, or both, where the sidelink DRX information includes an indication of the value of the activity timer associated with the DRX cycle. In some examples, the mode component1020may determine a value of an inactivity timer associated with a DRX cycle based on a relay service associated with a second UE or a QoS associated with data traffic for the UE, or both, where the sidelink DRX information includes an indication of the value of the inactivity timer associated with the DRX cycle.

In some examples, determining an offset between a beginning of a DRX cycle and a beginning 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 for the UE, or both, where the sidelink DRX information includes an indication of the offset. In some examples, the mode component1020may determine a first sidelink DRX pattern associated with the sidelink DRX configuration for monitoring a sidelink channel to receive a discovery signal based on the sidelink DRX configuration. In some examples, the mode component1020may determine a second sidelink DRX pattern 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, where the first sidelink DRX pattern is different from the second sidelink DRX pattern.

In some examples, determining a UE-specific offset duration associated with an active duration of a DRX cycle based on the sidelink DRX configuration, where monitoring the sidelink channel includes. In some examples, the mode component1020may enable a DRX mode based on the message. In some examples, the mode component1020may enable a DRX mode based on a QoS associated with pending data traffic satisfying a QoS threshold. In some examples, the mode component1020may enable a DRX mode based on a power level of the UE satisfying a power level threshold. In some cases, the sidelink DRX configuration includes a first indication of the first sidelink DRX pattern or a second indication of the second sidelink DRX pattern, or both. In some cases, the temporal period is common to the group of UEs. In some cases, the UE-specific offset duration is based on a L2identifier associated with the UE.

The discover component1025may receive a discovery request message from a second UE during the active duration of the DRX cycle. In some examples, the discover component1025may transmit a discovery response message to a second UE during the active duration of the DRX cycle. In some examples, the discover component1025may monitor 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. In some examples, the discover component1025may receive the discovery signal from the second UE based on the monitoring. In some examples, the discover component1025may broadcast a discovery request message during the active duration of the DRX cycle based on the sidelink DRX configuration.

In some examples, the discover component1025may monitor the sidelink channel to receive a discovery response message from the second UE during the active duration of the DRX cycle. In some examples, the discover component1025may receive the discovery response message from the second UE based on the monitoring, the discovery signal including the discovery response message. In some examples, the discover component1025may determine, based on the sidelink DRX configuration, a sidelink DRX pattern for monitoring the sidelink channel to receive the discovery signal from the second UE, the sidelink DRX pattern including the DRX cycle including the active duration and an inactive duration. In some examples, the discover component1025may broadcast a discovery request message during an inactive duration of a DRX cycle associated with the group of UEs based on a data traffic condition for the UE, where the inactive duration is common to the group of UEs, 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 the sidelink channel to receive the discovery signal from the second UE.

The relay component1030may select the second UE for relay communications between the UE and the base station, or between the UE and a third UE, or both, based on the discovery signal, where the relay communications correspond to a L2forwarding function or a L3forwarding function. In some examples, the relay component1030may receive a synchronization signal from the second UE on a sidelink broadcast channel. In some examples, the relay component1030may synchronize with the second UE based on the synchronization signal.

The network component1035may receive a downlink signal from the base station using a cellular link based on the sidelink DRX configuration. In some examples, the network component1035may transmit an uplink signal to the base station using the cellular link based on the sidelink DRX configuration. In some examples, the network component1035may determine, based on the sidelink DRX configuration, a sidelink DRX pattern for receiving the downlink signal or transmitting the uplink signal, or both, the sidelink DRX pattern including a DRX cycle including an active duration and an inactive duration, where receiving the downlink signal or transmitting the uplink signal, or both, is based on the sidelink DRX pattern. In some examples, the network component1035may receive a downlink signal from a base station during an inactive duration of a DRX cycle associated with the group of UEs. In some examples, the network component1035may transmit an uplink signal 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.

The message component1040may receive an RRC reconfiguration message including the sidelink DRX configuration from the base station. In some examples, the message component1040may transmit a 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.

The resource pool component1045may refrain from monitoring one or more resource pools during an inactive duration of a DRX cycle based on the group sidelink DRX configuration. In some examples, the resource pool component1045may refrain from 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 for the discovery signal.

The synchronization component1050may synchronize with the group of UEs based on a synchronization signal received on a sidelink broadcast channel from at least one UE associated with the group of UEs. In some examples, the synchronization component1050may transmit a synchronization signal to the second UE on a sidelink broadcast channel. In some examples, the synchronization component1050may synchronize with the second UE based on the synchronization signal. The sidelink component1055may establish a connection with the second UE to relay communications for the UE, where the relay communications correspond to a L2forwarding function or a L3forwarding function.

FIG.11shows a diagram of a system1100including a device1105in accordance with one or more aspects of the present disclosure. The device1105may be an example of or include the components of device805, device905, or a UE115as described herein. The device1105may include components for bi-directional voice and data communications including components for transmitting and receiving communications, including a UE communications manager1110, an I/O controller1115, a transceiver1120, an antenna1125, memory1130, and a processor1140. These components may be in electronic communication via one or more buses (e.g., bus1145).

The UE communications manager1110may transmit sidelink DRX information to a base station while operating in a connected mode. The UE communications manager1110may 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.

The UE communications manager1110may also receive a message including a group sidelink DRX configuration associated with a group of UEs while operating in an out-of-coverage mode, an idle mode, or an inactive mode. The UE communications manager1110may determine a temporal period to enable discontinuous monitoring of a sidelink channel based on the group sidelink DRX configuration, and monitor the sidelink channel during the temporal period.

The UE communications manager1110may also determine a DRX cycle based on a sidelink DRX configuration, the DRX cycle including an active duration and an inactive duration. The UE communications manager1110may receive a discovery request message from a second UE during the active duration of the DRX cycle, and transmit a discovery response message to a second UE during the active duration of the DRX cycle.

The I/O controller1115may manage input and output signals for the device1105. The I/O controller1115may also manage peripherals not integrated into the device1105. In some cases, the I/O controller1115may represent a physical connection or port to an external peripheral. In some cases, the I/O controller1115may utilize an operating system such as iOS®, ANDROID®, MS-DOS®, MS-WINDOWS®, OS/2®, UNIX®, LINUX®, or another known operating system. In other cases, the I/O controller1115may represent or interact with a modem, a keyboard, a mouse, a touchscreen, or a similar device. In some cases, the I/O controller1115may be implemented as part of a processor. In some cases, a user may interact with the device1105via the I/O controller1115or via hardware components controlled by the I/O controller1115.

The memory1130may include RAM and ROM. The memory1130may store computer-readable, computer-executable code1135including instructions that, when executed, cause the processor1140to perform various functions described herein. In some cases, the memory1130may contain, among other things, a BIOS which may control basic hardware or software operation such as the interaction with peripheral components or devices.

The code1135may include instructions to implement aspects of the present disclosure, including instructions to support wireless communications. The code1135may be stored in a non-transitory computer-readable medium such as system memory or other type of memory. In some cases, the code1135may not be directly executable by the processor1140but may cause a computer (e.g., when compiled and executed) to perform functions described herein.

The receiver1210may 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 communications in wireless communications systems, etc.). Information may be passed on to other components of the device1205. The receiver1210may be an example of aspects of the transceiver1520described with reference toFIG.15. The receiver1210may utilize a single antenna or a set of antennas.

The base station communications manager1215may receive sidelink DRX information from a UE, determine a sidelink DRX pattern for the UE based on the sidelink DRX information, and transmit a message including a sidelink DRX configuration including an indication of the sidelink DRX pattern for the UE. The base station communications manager1215may be an example of aspects of the base station communications manager1510described herein.

The transmitter1220may transmit signals generated by other components of the device1205. In some examples, the transmitter1220may be collocated with a receiver1210in a transceiver module. For example, the transmitter1220may be an example of aspects of the transceiver1520described with reference toFIG.15. The transmitter1220may utilize a single antenna or a set of antennas.

FIG.13shows a block diagram1300of a device1305in accordance with one or more aspects of the present disclosure. The device1305may be an example of aspects of a device1205, or a base station105as described herein. The device1305may include a receiver1310, a base station communications manager1315, and a transmitter1330. The device1305may also include a processor. Each of these components may be in communication with one another (e.g., via one or more buses).

The receiver1310may 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 communications in wireless communications systems, etc.). Information may be passed on to other components of the device1305. The receiver1310may be an example of aspects of the transceiver1520described with reference toFIG.15. The receiver1310may utilize a single antenna or a set of antennas.

The base station communications manager1315may be an example of aspects of the base station communications manager1215as described herein. The base station communications manager1315may include a sidelink information component1320and a sidelink configuration component1325. The base station communications manager1315may be an example of aspects of the base station communications manager1510described herein. The sidelink information component1320may receive sidelink DRX information from a UE. The sidelink configuration component1325may determine a sidelink DRX pattern for the UE based on the sidelink DRX information and transmit a message including a sidelink DRX configuration including an indication of the sidelink DRX pattern for the UE.

The transmitter1330may transmit signals generated by other components of the device1305. In some examples, the transmitter1330may be collocated with a receiver1310in a transceiver module. For example, the transmitter1330may be an example of aspects of the transceiver1520described with reference toFIG.15. The transmitter1330may utilize a single antenna or a set of antennas.

FIG.14shows a block diagram1400of a base station communications manager1405in accordance with one or more aspects of the present disclosure. The base station communications manager1405may be an example of aspects of a base station communications manager1215, a base station communications manager1315, or a base station communications manager1510described herein. The base station communications manager1405may include a sidelink information component1410, a sidelink configuration component1415, and a mode component1420. Each of these modules may communicate, directly or indirectly, with one another (e.g., via one or more buses).

The sidelink information component1410may receive sidelink DRX information from a UE. In some examples, the sidelink information component1410may receive UAI including the sidelink DRX information from the UE. The sidelink configuration component1415may determine a sidelink DRX pattern for the UE based on the sidelink DRX information. In some examples, the sidelink configuration component1415may transmit a message including a sidelink DRX configuration including an indication of the sidelink DRX pattern for the UE. In some examples, the sidelink configuration component1415may transmit an RRC reconfiguration message including the sidelink DRX configuration to the UE. In some examples, the sidelink configuration component1415may receive an RRC reconfiguration complete message to the base station 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.

The mode component1420may determine the sidelink DRX pattern for the UE based on a resource pool configuration for the UE. In some examples, the mode component1420may determine a first sidelink DRX pattern associated with the sidelink DRX configuration for monitoring a sidelink channel for a discovery signal at the UE based on the sidelink DRX information. In some examples, the mode component1420may determine a second sidelink DRX pattern associated with the 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 pattern is different from the second sidelink DRX pattern.

FIG.15shows a diagram of a system1500including a device1505in accordance with one or more aspects of the present disclosure. The device1505may be an example of or include the components of device1205, device1305, or a base station105as described herein. The device1505may include components for bi-directional voice and data communications including components for transmitting and receiving communications, including a base station communications manager1510, a network communications manager1515, a transceiver1520, an antenna1525, memory1530, a processor1540, and an inter-station communications manager1545. These components may be in electronic communication via one or more buses (e.g., bus1550).

The base station communications manager1510may receive sidelink DRX information from a UE, determine a sidelink DRX pattern for the UE based on the sidelink DRX information, and transmit a message including a sidelink DRX configuration including an indication of the sidelink DRX pattern for the UE.

The network communications manager1515may manage communications with the core network (e.g., via one or more wired backhaul links). For example, the network communications manager1515may manage the transfer of data communications for client devices, such as one or more UEs115.

The memory1530may include RAM, ROM, or a combination thereof. The memory1530may store computer-readable code1535including instructions that, when executed by a processor (e.g., the processor1540) cause the device to perform various functions described herein. In some cases, the memory1530may contain, among other things, a BIOS which may control basic hardware or software operation such as the interaction with peripheral components or devices.

At1605, the UE may transmit sidelink DRX information to a base station while operating in a connected mode. The operations of1605may be performed according to the methods described herein. In some examples, aspects of the operations of1605may be performed by a sidelink information component as described with reference toFIGS.8through11.

At1610, the UE may receive a message including a sidelink DRX configuration from the base station based on the sidelink DRX information. The operations of1610may be performed according to the methods described herein. In some examples, aspects of the operations of1610may be performed by a sidelink configuration component as described with reference toFIGS.8through11.

At1615, the UE may operate according to the sidelink DRX configuration. The operations of1615may be performed according to the methods described herein. In some examples, aspects of the operations of1615may be performed by a mode component as described with reference toFIGS.8through11.

FIG.17shows a flowchart illustrating a method1700in accordance with one or more aspects of the present disclosure. The operations of method1700may be implemented by a UE115or its components as described herein. For example, the operations of method1700may be performed by a UE communications manager as described with reference toFIGS.8through11. In some examples, a UE may execute a set of instructions to control the functional elements of the UE to perform the functions described below. Additionally or alternatively, a UE may perform aspects of the functions described below using special-purpose hardware.

At1705, the UE may receive a message including a group sidelink DRX configuration associated with a group of UEs while operating in an out-of-coverage mode, an idle mode, or an inactive mode. The operations of1705may be performed according to the methods described herein. In some examples, aspects of the operations of1705may be performed by a sidelink configuration component as described with reference toFIGS.8through11.

At1710, the UE may determine a temporal period to enable discontinuous monitoring of a sidelink channel based on the group sidelink DRX configuration. The operations of1710may be performed according to the methods described herein. In some examples, aspects of the operations of1710may be performed by a mode component as described with reference toFIGS.8through11.

At1715, the UE may monitor the sidelink channel during the temporal period. The operations of1715may be performed according to the methods described herein. In some examples, aspects of the operations of1715may be performed by a mode component as described with reference toFIGS.8through11.

At1805, 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 operations of1805may be performed according to the methods described herein. In some examples, aspects of the operations of1805may be performed by a sidelink configuration component as described with reference toFIGS.8through11.

At1810, the UE may receive a discovery request message from a second UE during the active duration of the DRX cycle. The operations of1810may be performed according to the methods described herein. In some examples, aspects of the operations of1810may be performed by a discover component as described with reference toFIGS.8through11.

At1815, the UE may transmit a discovery response message to a second UE during the active duration of the DRX cycle. The operations of1815may be performed according to the methods described herein. In some examples, aspects of the operations of1815may be performed by a discover component as described with reference toFIGS.8through11.

At1905, the base station may receive sidelink DRX information from a UE. The operations of1905may be performed according to the methods described herein. In some examples, aspects of the operations of1905may be performed by a sidelink information component as described with reference toFIGS.12through15.

At1910, the base station may determine a sidelink DRX pattern for the UE based on the sidelink DRX information. The operations of1910may be performed according to the methods described herein. In some examples, aspects of the operations of1910may be performed by a sidelink configuration component as described with reference toFIGS.12through15.

At1915, the base station may transmit a message including a sidelink DRX configuration including an indication of the sidelink DRX pattern for the UE. The operations of1915may be performed according to the methods described herein. In some examples, aspects of the operations of1915may be performed by a sidelink configuration component as described with reference toFIGS.12through15.

The following provides an overview of examples of the present disclosure:

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

Example 2: The method of 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 cycle based at least in part on the sidelink discontinuous reception configuration; and receiving the discovery signal from the second UE based at least in part on the monitoring.

Example 3: The method of examples 1 or 2, wherein the sidelink discontinuous reception configuration is based at least in part 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.

Example 4: The method of examples 2 to 3, further comprising: broadcasting a discovery request message during the active duration of the discontinuous reception cycle based at least in part on the sidelink discontinuous reception configuration; monitoring the sidelink channel to receive a discovery response message from the second UE during the active duration of the discontinuous reception cycle; and receiving the discovery response message from the second UE based at least in part on the monitoring, the discovery signal comprising the discovery response message.

Example 5: The method of examples 2 to 4, further comprising: selecting the second UE for relay communications between the UE and the base station, or between the UE and a third UE, or both, based at least in part on the discovery signal, wherein the relay communications correspond to a layer2(L2) forwarding function or a layer3(L3) forwarding function.

Example 6: The method of examples 2 to 5, further comprising: determining, based at least in part on the sidelink discontinuous reception configuration, a sidelink discontinuous reception pattern for monitoring the sidelink channel to receive the discovery signal from the second UE, the sidelink discontinuous reception pattern comprising the discontinuous reception cycle including the active duration and an inactive duration.

Example 7: The method of examples 2 to 6, further comprising: receiving a synchronization signal from the second UE on a sidelink broadcast channel; and synchronizing with the second UE based at least in part on the synchronization signal.

Example 8: The method of examples 1 to 7, further comprising: receiving a downlink signal from the base station using a cellular link based at least in part on the sidelink discontinuous reception configuration; or transmitting an uplink signal to the base station using the cellular link based at least in part on the sidelink discontinuous reception configuration.

Example 9: The method of example 8, further comprising: determining, based at least in part on the sidelink discontinuous reception configuration, a sidelink discontinuous reception pattern for receiving the downlink signal or transmitting the uplink signal, or both, the sidelink discontinuous reception pattern comprising a discontinuous reception cycle including an active duration and an inactive duration, wherein receiving the downlink signal or transmitting the uplink signal, or both, is based at least in part on the sidelink discontinuous reception pattern.

Example 10: The method of examples 1 to 9, wherein receiving the message comprises: receiving a radio resource control reconfiguration message including the sidelink discontinuous reception configuration from the base station.

Example 11: The method of example 10, further comprising: transmitting a radio resource control reconfiguration complete message to the base station based at least in part on the radio resource control reconfiguration message, wherein operating according to the sidelink discontinuous reception configuration is based at least in part on the radio resource control reconfiguration complete message.

Example 12: The method of examples 1 to 11, further comprising: including the sidelink discontinuous reception information in UE-assistance information; and transmitting the UE-assistance information comprising the sidelink discontinuous reception information to the base station while operating in the connected mode, wherein receiving the message including the sidelink discontinuous reception configuration is based at least in part on the UE-assistance information.

Example 13: The method of examples 1 to 12, further comprising: determining a single connected mode discontinuous reception cycle for sidelink communications or cellular communications, or both, based at least in part on the sidelink discontinuous reception configuration, wherein operating according to the sidelink discontinuous reception configuration is based at least in part on the single connected mode discontinuous reception cycle.

Example 14: The method of examples 1 to 13, further comprising: determining a discontinuous reception cycle 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 comprises an indication of the discontinuous reception cycle.

Example 15: The method of examples 1 to 14, further comprising: determining a value of an activity timer associated with a discontinuous reception cycle 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 comprises an indication of the value of the activity timer associated with the discontinuous reception cycle.

Example 16: The method of examples 1 to 15, further comprising: determining a value of an inactivity timer associated with a discontinuous reception cycle 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 comprises an indication of the value of the inactivity timer associated with the discontinuous reception cycle.

Example 17: The method of examples 1 to 16, further comprising: determining an offset between a beginning of a discontinuous reception cycle and a beginning of an active duration of the discontinuous reception cycle 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 comprises an indication of the offset.

Example 18: The method of examples 1 to 17, further comprising: determining a first sidelink discontinuous reception pattern 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 pattern 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 pattern is different from the second sidelink discontinuous reception pattern.

Example 19: The method of example 18, wherein the sidelink discontinuous reception configuration comprises a first indication of the first sidelink discontinuous reception pattern or a second indication of the second sidelink discontinuous reception pattern, or both.

Example 20: The method of examples 1 to 19, wherein the sidelink discontinuous reception configuration comprises a connected mode discontinuous reception configuration.

Example 21: The method of examples 1 to 20, wherein the sidelink discontinuous reception configuration comprises a sidelink discontinuous reception preference associated with a discovery procedure comprising a first model discovery procedure or a second model discovery procedure.

Example 22: The method of examples 1 to 21, wherein the sidelink discontinuous reception configuration comprises 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.

Example 23: The method of examples 1 to 22, wherein the UE comprises a remote UE and a second UE comprises a rely UE between the remote UE and the base station.

Example 24: A method for wireless communication at a UE is described. The method may include: receiving a message including a group sidelink discontinuous reception configuration associated with a group of UEs while operating in an out-of-coverage mode, an idle mode, or an inactive mode; determining a temporal period to enable discontinuous monitoring of a sidelink channel based at least in part on the group sidelink discontinuous reception configuration; and monitoring the sidelink channel during the temporal period.

Example 25: The method of example 24, wherein receiving the message comprises: receiving a system information block or a radio resource control reconfiguration message including the group sidelink discontinuous reception configuration.

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

Example 27: The method of example 25, further comprising: disabling a discontinuous reception mode based at least in part on a quality-of-service associated with pending data traffic satisfying a quality-of-service threshold.

Example 28: The method of examples 24 to 27, wherein the group sidelink discontinuous reception configuration comprises a discontinuous reception periodicity common to the group of UEs.

Example 29: The method of examples 24 to 28, wherein the sidelink discontinuous reception configuration comprises an active duration of a discontinuous reception cycle common to the group of UEs.

Example 30: The method of examples 24 to 29, wherein the sidelink discontinuous reception configuration comprises a group offset duration between a beginning of a discontinuous reception cycle and an active duration of the discontinuous reception cycle, wherein the group offset duration is common to the group of UEs.

Example 31: The method of examples 24 to 30, wherein the temporal period is common to the group of UEs.

Example 32: The method of examples 24 to 31, wherein the UE is grouped in the group of UEs based at least in part on a pathloss parameter.

Example 33: The method of examples 24 to 32, wherein the UE is grouped in the group of UEs based at least in part on a quality-of-service associated with data traffic of the UE.

Example 34: The method of examples 24 to 22, further comprising: determining a UE-specific offset duration associated with an active duration of a discontinuous reception cycle based at least in part on the sidelink discontinuous reception configuration, wherein monitoring the sidelink channel comprises; and monitoring the sidelink channel during the active duration of the discontinuous reception cycle based at least in part on the UE-specific offset duration.

Example 35: The method of example 34, wherein the UE-specific offset duration is based at least in part on a layer2(L2) identifier associated with the UE.

Example 36: The method of example 24 to 35, further comprising: enabling a discontinuous reception mode based at least in part on the message.

Example 37: The method of examples 24 to 36, further comprising: enabling a discontinuous reception mode based at least in part on a quality-of-service associated with pending data traffic satisfying a quality-of-service threshold.

Example 38: The method of examples 24 to 37, further comprising: enabling a discontinuous reception mode based at least in part on a power level of the UE satisfying a power level threshold.

Example 39: The method of examples 24 to 38, further comprising: refraining from monitoring one or more resource pools during an inactive duration of a discontinuous reception cycle based at least in part on the group sidelink discontinuous reception configuration.

Example 40: The method of examples 24 to 39, further comprising: refraining from monitoring one or more resource pools associated with monitoring the sidelink channel for a discovery signal based at least in part on a group resource pool configuration associated with monitoring for the discovery signal.

Example 41: The method of examples 24 to 40, further comprising: broadcasting a discovery request message during an inactive duration of a discontinuous reception cycle associated with the group of UEs based at least in part on a data traffic condition for the UE, wherein the inactive duration is common to the group of UEs, wherein the inactive duration and the discontinuous reception cycle are common to the group of UEs.

Example 42: The method of examples 24 to 41, further comprising: receiving a downlink signal from a base station during an inactive duration of a discontinuous reception cycle associated with the group of UEs; or transmitting an uplink signal to the base station during the inactive duration of the discontinuous reception cycle associated with the group of UEs, wherein the inactive duration and the discontinuous reception cycle are common to the group of UEs.

Example 43: The method of examples 24 to 42, further comprising: synchronizing with the group of UEs based at least in part on a synchronization signal received on a sidelink broadcast channel from at least one UE associated with the group of UEs.

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

Example 45: The method of example 44, wherein the sidelink discontinuous reception configuration is based at least in part 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.

Example 46: The method of examples 44 or 45, further comprising: establishing a connection with the second UE to relay communications for the UE, wherein the relay communications correspond to a layer2(L2) forwarding function or a layer3(L3) forwarding function.

Example 47: The method of examples 44 to 46, further comprising: transmitting a synchronization signal to the second UE on a sidelink broadcast channel; and synchronizing with the second UE based at least in part on the synchronization signal.

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 pattern for the UE based at least in part on the sidelink discontinuous reception information; and transmitting a message comprising a sidelink discontinuous reception configuration including an indication of the sidelink discontinuous reception pattern for the UE.

Example 49: The method of example 48, wherein transmitting the message comprises: transmitting a radio resource control reconfiguration message including the sidelink discontinuous reception configuration to the UE.

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

Example 51: The method of examples 48 to 50, further comprising: receiving UE-assistance information including the sidelink discontinuous reception information from the UE.

Example 52: The method of examples 48 to 51, further comprising: determining the sidelink discontinuous reception pattern for the UE based at least in part on a resource pool configuration for the UE.

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

Example 54: The method of examples 48 to 53, wherein the sidelink discontinuous reception configuration comprises a connected mode discontinuous reception configuration.

Example 55: The method of examples 48 to 54, wherein the sidelink discontinuous reception configuration comprises a sidelink discontinuous reception preference.

Example 56: An apparatus for wireless communication comprising a processor; and memory coupled to the processor, the processor and memory configured to perform a method of any of examples 1-23.

Example 57: An apparatus for wireless communication comprising at least one means for performing a method of any of examples 1-23.

Example 58: A computer-readable medium storing code for wireless communication, the code comprising instructions executable by a processor to perform a method of any of examples 1-23.

Example 59: An apparatus for wireless communication comprising a processor; and memory coupled to the processor, the processor and memory configured to perform a method of any of examples 24-43.

Example 60: An apparatus for wireless communication comprising at least one means for performing a method of any of examples 24-43.

Example 61: A computer-readable medium storing code for wireless communication, the code comprising instructions executable by a processor to perform a method of any of examples 24-43.

Example 62: An apparatus for wireless communication comprising a processor; and memory coupled to the processor, the processor and memory configured to perform a method of any of examples 44-47.

Example 63: An apparatus for wireless communication comprising at least one means for performing a method of any of examples 44-47.

Example 64: A computer-readable medium storing code for wireless communication, the code comprising instructions executable by a processor to perform a method of any of examples 44-47.

Example 65: An apparatus for wireless communication comprising a processor; and memory coupled to the processor, the processor and memory configured to perform a method of any of examples 48-55.

Example 66: An apparatus for wireless communication comprising at least one means for performing a method of any of examples 48-55.

Example 67: A computer-readable medium storing code for wireless communication, the code comprising instructions executable by a processor to perform a method of any of examples 48-55.