Discovery reference signal window configuration for sidelink

Abstract

Methods, systems, and devices for wireless communication are described. The described techniques provide for a user equipment (UE) supporting a communication of synchronization information, via sidelink synchronization signal blocks (S-SSBs), to other UEs using sidelink channels. The UE may be configured with one or more discovery reference signal (DRS) windows that include multiple S-SSB reception occasions and multiple S-SSB transmission occasions. The UE may monitor for transmission of the S-SSB during the reception occasions and transmit the S-SSB during the transmission occasions.

Description

DISCOVERY REFERENCE SIGNAL WINDOW CONFIGURATION FOR SIDELINKCROSS REFERENCES

[0001] The present Application for Patent claims priority to Greek Patent Application No. 20220100680 by LIU et al., entitled “DISCOVERY REFERENCE SIGNAL WINDOW CONFIGURATION FOR SIDELINK ” filed August 11, 2022, which is assigned to the assignee hereof and expressly incorporated by reference herein.FIELD OF TECHNOLOGY

[0002] The following relates to wireless communication, including discovery reference signal window configuration for sidelink.BACKGROUND

[0003] Wireless communications systems are widely deployed to provide various ty pes of communication content such as voice, video, packet data, messaging, broadcast, and so on. These systems may be capable of supporting communication with multiple users by sharing the available system resources (e.g., time, frequency, and power). Examples of such multiple-access systems include fourth generation (4G) systems such as Long Term Evolution (LTE) systems, LTE-Advanced (LTE-A) systems, or LTE-A Pro systems, and fifth generation (5G) systems which may be referred to as New Radio (NR) systems. These systems may employ technologies such as code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), orthogonal FDMA (OFDMA), or discrete Fourier transform spread orthogonal frequency division multiplexing (DFT-S-OFDM). A wireless multiple-access communications system may include one or more base stations, each supporting wireless communication for communication devices, which may be known as user equipment (UE).

[0004] Wireless communications systems may support communications between UEs, and such communications may be referred to as sidelink communications. In some cases, a first UE may relay control information and data, from a network, to a second UE using sidelink channels. The second UE may be out-of-coverage from the network,and the sidelink communication techniques may support communications between the second UE and the networkSUMMARY

[0005] The described techniques relate to improved methods, systems, devices, and apparatuses that support discovery reference signal window configuration for sidelink. For example, the described techniques provide for a user equipment (UE) supporting a communication of synchronization information, via sidelink synchronization signal blocks (SSBs), to other UEs using sidelink channels. The UE may be configured with one or more discovery reference signal (DRS) windows that include multiple S-SSB reception occasions and multiple S-SSB transmission occasions. The UE may monitor for transmission of a S-SSB during the reception occasions and on a first sidelink channel and transmit the S-SSB during the transmission occasions and on a second sidelink channel. As such, the configuration of the one or more DRS windows may support communication of the synchronization information to multiple UEs using sidelink channels.

[0006] A method for wireless communication at a first user equipment (UE) is described. The method may include receiving signaling that indicates a configuration for one or more discovery reference signal windows, the one or more discovery reference signal windows including two or more synchronization signal block reception occasions and two or more synchronization signal block transmission occasions in accordance with the configuration, monitoring, based on the configuration, for a reception of a first sidelink synchronization signal block message from a second UE during the two or more synchronization signal block reception occasions of the one or more discovery reference signal windows, and transmitting, based on the configuration, a second sidelink synchronization signal block message to a third UE during at least one synchronization signal block transmission occasion of the two or more synchronization signal block transmission occasions of the one or more discovery reference signal windows.

[0007] An apparatus for wireless communication at a first UE is described. The apparatus may include a processor, memory coupled with the processor, and instructions stored in the memory. The instructions may be executable by the processorto cause the apparatus to receive signaling that indicates a configuration for one or more discovery reference signal windows, the one or more discovery reference signal windows including two or more synchronization signal block reception occasions and two or more synchronization signal block transmission occasions in accordance with the configuration, monitor, based on the configuration, for a reception of a first sidelink synchronization signal block message from a second UE during the two or more synchronization signal block reception occasions of the one or more discovery reference signal windows, and transmit, based on the configuration, a second sidelink synchronization signal block message to a third UE during at least one synchronization signal block transmission occasion of the two or more synchronization signal block transmission occasions of the one or more discovery' reference signal windows.

[0008] Another apparatus for wireless communication at a first UE is described. The apparatus may include means for receiving signaling that indicates a configuration for one or more discovery reference signal windows, the one or more discovery reference signal windows including two or more synchronization signal block reception occasions and two or more synchronization signal block transmission occasions in accordance with the configuration, means for monitoring, based on the configuration, for a reception of a first sidelink synchronization signal block message from a second UE during the two or more synchronization signal block reception occasions of the one or more discovery reference signal windows, and means for transmitting, based on the configuration, a second sidelink synchronization signal block message to a third UE during at least one synchronization signal block transmission occasion of the two or more synchronization signal block transmission occasions of the one or more discovery reference signal windows.

[0009] A non-transitory computer-readable medium storing code for wireless communication at a first UE is described. The code may include instructions executable by a processor to receive signaling that indicates a configuration for one or more discovery reference signal windows, the one or more discovery reference signal windows including two or more synchronization signal block reception occasions and two or more synchronization signal block transmission occasions in accordance with the configuration, monitor, based on the configuration, for a reception of a first sidelink synchronization signal block message from a second UE during the two or moresynchronization signal block reception occasions of the one or more discovery reference signal windows, and transmit, based on the configuration, a second sidelink synchronization signal block message to a third UE during at least one synchronization signal block transmission occasion of the two or more synchronization signal block transmission occasions of the one or more discovery' reference signal windows.

[0010] In some examples of the method, apparatuses, and non-transitory computer- readable medium described herein, receiving the signaling that indicates the configuration may include operations, features, means, or instructions for receiving signaling that indicates a reception discovery reference signal window that includes the two or more synchronization signal block reception occasions and a transmission discovery reference signal window that includes the two or more synchronization signal block transmission occasions.

[0011] In some examples of the method, apparatuses, and non-transitory computer- readable medium described herein, resources of the reception discovery reference signal window and resources of the transmission discovery reference signal window may be non-overlapping in a time domain.

[0012] In some examples of the method, apparatuses, and non-transitory computer- readable medium described herein, resources of the reception discovery reference signal window and resources of the transmission discovery reference signal window may be at least partially overlapping in a time domain.

[0013] In some examples of the method, apparatuses, and non-transitory computer- readable medium described herein, at least one of the synchronization signal block reception occasions may be positioned between at least two of the synchronization signal block transmission occasions in a time domain.

[0014] In some examples of the method, apparatuses, and non-transitory computer- readable medium described herein, resources of the reception discovery reference signal window and resources of the transmission discovery reference signal window may be non-overlapping in a frequency domain.

[0015] In some examples of the method, apparatuses, and non-transitory computer- readable medium described herein, receiving the signaling that indicates theconfiguration may include operations, features, means, or instructions for receiving signaling that indicates a discovery reference signal window that includes the two or more synchronization signal block reception occasions and the two or more synchronization signal block transmission occasions.

[0016] In some examples of the method, apparatuses, and non-transitory computer- readable medium described herein, at least one of the synchronization signal block reception occasions may be positioned between at least two of the synchronization signal block transmission occasions in a time domain.

[0017] In some examples of the method, apparatuses, and non-transitory computer- readable medium described herein, receiving the signaling that indicates the configuration may include operations, features, means, or instructions for receiving an indication of a first quantity of the two or more synchronization signal block transmission occasions, a second quantity of the two or more synchronization signal block reception occasions, or both the first quantity and the second quantity.

[0018] In some examples of the method, apparatuses, and non-transitory computer- readable medium described herein, receiving the signaling that indicates the configuration may include operations, features, means, or instructions for receiving an indication of a separation within a time domain between a first synchronization signal block occasion and a second synchronization signal block occasion of the one or more discovery reference signal windows.

[0019] In some examples of the method, apparatuses, and non-transitory computer- readable medium described herein, the indication of the separation indicates a quantity of slots.

[0020] In some examples of the method, apparatuses, and non-transitory computer- readable medium described herein, the indicated quantity of slots may be zero.

[0021] Some examples of the method, apparatuses, and non-transitory computer- readable medium described herein may further include operations, features, means, or instructions for performing a listen-before-talk procedure during the one or more discovery reference signal windows, where the first UE transmits the second sidelinksynchronization signal block message in response to clearing the listen-before-talk procedure.

[0022] Some examples of the method, apparatuses, and non-transitory computer- readable medium described herein may further include operations, features, means, or instructions for receiving, from the second UE based on the monitoring, the first sidelink synchronization signal block message, where the first UE transmits the second sidelink synchronization signal block message during at least one synchronization signal block transmission occasion in response to receiving the first sidelink synchronization signal block message during at least one of the two or more synchronization signal block reception occasions.

[0023] Some examples of the method, apparatuses, and non-transitory computer- readable medium described herein may further include operations, features, means, or instructions for determining that a synchronization accuracy of the first UE satisfies a synchronization accuracy threshold, where the first UE transmits the second sidelink synchronization signal block message in response to determining that the synchronization accuracy of the first UE satisfies the synchronization accuracy threshold.

[0024] In some examples of the method, apparatuses, and non-transitory computer- readable medium described herein, each of the two or more synchronization signal block reception occasions and each of the two or more synchronization signal block transmission occasions corresponds to a respective slot of the one or more discovery reference signal windows.

[0025] A method for wireless communication at a first UE is described. The method may include receiving signaling that indicates a configuration for one or more discovery reference signal windows that each include a first synchronization signal block occasion for transmission of a first sidelink synchronization signal block message by a second UE, a second synchronization signal block occasion for transmission of a second sidelink synchronization signal block message by the first UE, and a set of additional synchronization signal block transmission occasions configured for use by any UE of a set of UEs including the first UE and the second UE, monitoring, based on the configuration, for transmission of the first sidelink synchronization signal blockmessage by the second UE during the first synchronization signal block occasion of the one or more discovery reference signal windows, attempting, based on the configuration, to transmit the second sidelink synchronization signal block message during the second synchronization signal block occasion of the one or more discovery reference signal windows, where whether the first UE monitors for transmission of the first sidelink synchronization signal block message by the second UE during the set of additional synchronization signal block transmission occasions is based on whether the first sidelink synchronization signal block message is received by the first UE during the first synchronization signal block occasion, and where whether the first UE transmits the second sidelink synchronization signal block message during the set of additional synchronization signal block transmission occasions is based on whether the second sidelink synchronization signal block message is transmitted by the first UE during the second synchronization signal block occasion.

[0026] An apparatus for wireless communication at a first UE is described. The apparatus may include a processor, memory coupled with the processor, and instructions stored in the memory. The instructions may be executable by the processor to cause the apparatus to receive signaling that indicates a configuration for one or more discovery reference signal windows that each include a first synchronization signal block occasion for transmission of a first sidelink synchronization signal block message by a second UE, a second synchronization signal block occasion for transmission of a second sidelink synchronization signal block message by the first UE, and a set of additional synchronization signal block transmission occasions configured for use by any UE of a set of UEs including the first UE and the second UE, monitor, based on the configuration, for transmission of the first sidelink synchronization signal block message by the second UE during the first synchronization signal block occasion of the one or more discovery reference signal windows, attempt, based on the configuration, to transmit the second sidelink synchronization signal block message during the second synchronization signal block occasion of the one or more discovery reference signal windows, where whether the first UE monitors for transmission of the first sidelink synchronization signal block message by the second UE during the set of additional synchronization signal block transmission occasions be based on whether the first sidelink synchronization signal block message is received by the first UE during thefirst synchronization signal block occasion, and where whether the first UE transmit the second sidelink synchronization signal block message during the set of additional synchronization signal block transmission occasions is based on whether the second sidelink synchronization signal block message is transmitted by the first UE during the second synchronization signal block occasion.

[0027] Another apparatus for wireless communication at a first UE is described. The apparatus may include means for receiving signaling that indicates a configuration for one or more discovery reference signal windows that each include a first synchronization signal block occasion for transmission of a first sidelink synchronization signal block message by a second UE, a second synchronization signal block occasion for transmission of a second sidelink synchronization signal block message by the first UE, and a set of additional synchronization signal block transmission occasions configured for use by any UE of a set of UEs including the first UE and the second UE, means for monitoring, based on the configuration, for transmission of the first sidelink synchronization signal block message by the second UE during the first synchronization signal block occasion of the one or more discovery reference signal windows, means for attempting, based on the configuration, to transmit the second sidelink synchronization signal block message during the second synchronization signal block occasion of the one or more discovery reference signal windows, where whether the first UE monitors for transmission of the first sidelink synchronization signal block message by the second UE during the set of additional synchronization signal block transmission occasions is based on whether the first sidelink synchronization signal block message is received by the first UE during the first synchronization signal block occasion, and where whether the first UE transmits the second sidelink synchronization signal block message during the set of additional synchronization signal block transmission occasions is based on whether the second sidelink synchronization signal block message is transmitted by the first UE during the second synchronization signal block occasion.

[0028] A non-transitory computer-readable medium storing code for wireless communication at a first UE is described. The code may include instructions executable by a processor to receive signaling that indicates a configuration for one or more discovery reference signal windows that each include a first synchronization signalblock occasion for transmission of a first sidelink synchronization signal block message by a second UE, a second synchronization signal block occasion for transmission of a second sidelink synchronization signal block message by the first UE, and a set of additional synchronization signal block transmission occasions configured for use by any UE of a set of UEs including the first UE and the second UE, monitor, based on the configuration, for transmission of the first sidelink synchronization signal block message by the second UE during the first synchronization signal block occasion of the one or more discovery reference signal windows, attempt, based on the configuration, to transmit the second sidelink synchronization signal block message during the second synchronization signal block occasion of the one or more discovery reference signal windows, where whether the first UE monitors for transmission of the first sidelink synchronization signal block message by the second UE during the set of additional synchronization signal block transmission occasions be based on whether the first sidelink synchronization signal block message is received by the first UE during the first synchronization signal block occasion, and where whether the first UE transmit the second sidelink synchronization signal block message during the set of additional synchronization signal block transmission occasions is based on whether the second sidelink synchronization signal block message is transmitted by the first UE during the second synchronization signal block occasion.

[0029] In some examples of the method, apparatuses, and non-transitory computer- readable medium described herein, attempting to transmit the second sidelink synchronization signal block message during the second synchronization signal block occasion includes performing a hsten-before-talk procedure during the second synchronization signal block occasion and the method, apparatuses, and non-transitory computer-readable medium may include further operations, features, means, or instructions for transmitting the second sidelink synchronization signal block message during a synchronization signal block transmission occasion of the set of additional synchronization signal block transmission occasions based on a failure of the listen- before-talk procedure during the second synchronization signal block occasion.

[0030] 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 absence of the first sidelink synchronization signal blockmessage from the first synchronization signal block occasion based on the monitoring during the first synchronization signal block occasion and monitoring for transmission of the first sidelink synchronization signal block message by the second UE during a synchronization signal block transmission occasion of the set of additional synchronization signal block transmission occasions based on the absence of the first sidelink synchronization signal block message from the first synchronization signal block occasion.

[0031] Some examples of the method, apparatuses, and non-transitory computer- readable medium described herein may further include operations, features, means, or instructions for determining that a synchronization accuracy of the first UE does may be lower than a synchronization accuracy threshold and monitoring for transmission of the first sidelink synchronization signal block message by the second UE during a synchronization signal block transmission occasion of the set of additional synchronization signal block transmission occasions based on determining that the synchronization accuracy of the first UE may be lower than the synchronization accuracy threshold.

[0032] Some examples of the method, apparatuses, and non-transitory computer- readable medium described herein may further include operations, features, means, or instructions for receiving the first sidelink synchronization signal block message during a first additional synchronization signal block transmission occasion of the set of additional synchronization signal block transmission occasions and transmitting the second sidelink synchronization signal block message during a second additional synchronization signal block transmission occasion of the set of additional synchronization signal block transmission occasions based on receiving the first sidelink synchronization signal block message during the first additional synchronization signal block transmission occasion.

[0033] In some examples of the method, apparatuses, and non-transitory computer- readable medium described herein, each of the first synchronization signal block occasion, the second synchronization signal block occasion, and the additional synchronization signal block transmission occasions corresponds to a respective slot of the one or more discovery reference signal windows.BRIEF DESCRIPTION OF THE DRAWINGS

[0034] FIG. 1 illustrates an example of a wireless communications system that supports discovery reference signal window configuration for sidelink in accordance with one or more aspects of the present disclosure.

[0035] FIG. 2 illustrates an example of a wireless communication system that supports discovery reference signal window configuration for sidelink in accordance with one or more aspects of the present disclosure.

[0036] FIG. 3A and FIG. 3B illustrate examples of resource diagrams that support discovery reference signal window configuration for sidelink in accordance with one or more aspects of the present disclosure.

[0037] FIG. 4 illustrates an example of a resource diagram that supports discovery reference signal window configuration for sidelink in accordance with one or more aspects of the present disclosure.

[0038] FIG. 5 illustrates an example of a process flow that supports discovery reference signal window configuration for sidelink in accordance with one or more aspects of the present disclosure.

[0039] FIG. 6 illustrates an example of a process flow that supports discovery reference signal window configuration for sidelink in accordance with one or more aspects of the present disclosure.

[0040] FIGs. 7 and 8 show block diagrams of devices that support discovery reference signal window configuration for sidelink in accordance with one or more aspects of the present disclosure.

[0041] FIG. 9 shows a block diagram of a communications manager that supports discovery reference signal window configuration for sidelink in accordance with one or more aspects of the present disclosure.

[0042] FIG. 10 shows a diagram of a system including a device that supports discovery reference signal window configuration for sidelink in accordance with one or more aspects of the present disclosure.

[0043] FIGs. 1 1 through 14 show flowcharts illustrating methods that support discovery reference signal window configuration for sidelink in accordance with one or more aspects of the present disclosure.DETAILED DESCRIPTION

[0044] Wireless communication systems may support sidelink communication (e.g., vehicle-to-everything (V2X) communications) between users equipments (UEs). In some examples, the UEs may share sidelink synchronization blocks (S-SSB) to support synchronization with a network entity by the UEs that receive the S-SSB. Some of the transmissions of these S-SSBs may be performed during a configured discovery reference signal (DRS) window. For example, a UE that is in coverage of a trusted synchronization source (e.g., the network entity) may receive synchronization information from the network entity. To benefit neighboring UEs that are not in the coverage of the network entity and have therefore not received the synchronization information, the UE may become a S-SSB transmitter (e.g., a first synchronization reference (syncRef) node) and transmit the S-SSBs containing the synchronization information from the network entity to the neighboring UEs.

[0045] One of the neighboring UEs (a second UE), which is not in coverage of the network entity, may receive these S-SSBs from the first syncRef node and use these S- SSBs to synchronize with the network entity . In some examples, the second UE may, based on some threshold and criteria (e.g., a distance between two UEs), determine to also transmit S-SSBs (becoming a second syncRef node) to another neighboring UE (a third UE). As such, the synchronization information may keep propagating through the system. However, half-duplex limitations at the UEs (e.g., the second UE) may limit the ability of the UEs to receive and / or transmit S-SSBs efficiently without interfering with other communications. Additionally, due to listen-before-talk (LBT) uncertainty in the system, the syncRef node may use additional opportunities to transmit the S-SSBs.

[0046] To support S-SSB transmission and reception in a wireless communications system, which may include half-duplex UEs, techniques described herein support configurations of one or more DRS windows that include multiple S-SSB transmission opportunities and multiple S-SSB reception opportunities. In one example, two DRS window configurations may be defined, where a first DRS window includes multiple S-SSB reception opportunities (e.g., resources) and a second DRS window includes multiple S-SSB transmission opportunities (e.g., resources). The two DRS windows may be contiguous and non-overlapping or time combinational (e.g., interleaved). In another example, one DRS window may be configured that includes S-SSB transmission opportunities and S-SSB transmission reception opportunities (e.g., in an interleaved pattern). Thus, two DRS windows may be configured for a UE, one for receiving S-SSBs by the UE and another for transmitting S-SSBs by the UE.

[0047] In some cases, configuration of a single DRS window may be used, where the single DRS window includes a first slot for S-SSB transmission by a first syncRef node (e.g., an upstream node), a second slot for S-SSB transmission by the second syncRef node (e.g., a downstream node), and a set of S-SSB opportunities (referred to as additional SSB transmission occasions) that may be used for either S-SSB reception or S-SSB transmission. Additionally, the first syncRef node may be limited from transmission during the second slot. Thus, a single DRS window may be configured in which different S-SSB occasions are assigned to different UEs as S-SSB transmission opportunities (subject to LBT by the assigned UE, with one or other UEs monitoring to potentially receive S-SSBs), and the single DRS window may further include one or more additional S-SSB occasions that any UE can use to transmit depending on whether that UE was able to transmit during its assigned S-SSB occasion earlier in the DRS window. In some such cases, if LBT fails in the legacy slots, then a second syncRef node may not receive the timing from a first syncRef node. To prevent possible timing issues, if the second syncRef determines that a timing / frequency accuracy is below a threshold, it may monitor for the S-SSB from the first syncRef node before it starts S- SSB transmission, therefore forgoing transmission opportunities until the S-SSB transmission is more likely to be accurate.

[0048] Aspects of the disclosure are initially described in the context of wireless communications systems. Aspects of the disclosure are further described with respect to a wireless communications system illustrating sidelink communication and network synchronization, resource diagrams, and process flow diagrams. Aspects of the disclosure are further illustrated by and described with reference to apparatus diagrams, system diagrams, and flowcharts that relate to discovery reference signal window configuration for sidelink.

[0049] FTG. 1 illustrates an example of a wireless communications system 100 that supports discovery reference signal window configuration for sidelink in accordance with one or more aspects of the present disclosure. The wireless communications system 100 may include one or more network entities 105, one or more UEs 115, and a core network 130. In some examples, the wireless communications system 100 may be a Long Term Evolution (LTE) network, an LTE- Advanced (LTE-A) network, an LTE- A Pro network, a New Radio (NR) network, or a network operating in accordance with other systems and radio technologies, including future systems and radio technologies not explicitly mentioned herein.

[0050] The network entities 105 may be dispersed throughout a geographic area to form the wireless communications system 100 and may include devices in different forms or having different capabilities. In various examples, a network entity 105 may be referred to as a network element, a mobility element, a radio access network (RAN) node, or network equipment, among other nomenclature. In some examples, network entities 105 and UEs 115 may wirelessly communicate via one or more communication links 125 (e.g., a radio frequency (RF) access link). For example, a network entity 105 may support a coverage area 110 (e.g., a geographic coverage area) over which the UEs 115 and the network entity 105 may establish one or more communication links 125. The coverage area 110 may be an example of a geographic area over which a network entity 105 and a UE 115 may support the communication of signals according to one or more radio access technologies (RATs).

[0051] The UEs 115 may be dispersed throughout a coverage area 110 of the wireless communications system 100, and each UE 115 may be stationary, or mobile, or both at different times. The UEs 115 may be devices in different forms or having different capabilities. Some example UEs 115 are illustrated in FIG. 1. The UEs 115 described herein may be capable of supporting communications with various ty pes of devices, such as other UEs 115 or network entities 105, as shown in FIG. 1.

[0052] As described herein, a node of the wireless communications system 100, which may be referred to as a network node, or a wireless node, may be a network entity 105 (e.g., any network entity described herein), a UE 115 (e.g., any UE described herein), a network controller, an apparatus, a device, a computing system, one or more components, or another suitable processing entity configured to perform any of thetechniques described herein. For example, a node may be a UE 1 15. As another example, a node may be a network entity 105. As another example, a first node may be configured to communicate with a second node or a third node. In one aspect of this example, the first node may be a UE 115, the second node may be a network entity 105, and the third node may be a UE 115. In another aspect of this example, the first node may be a UE 115, the second node may be a network entity 105, and the third node may be a network entity 105. In yet other aspects of this example, the first, second, and third nodes may be different relative to these examples. Similarly, reference to a UE 115, network entity 105, apparatus, device, computing sy stem, or the like may include disclosure of the UE 115, network entity 105, apparatus, device, computing system, or the like being a node. For example, disclosure that a UE 115 is configured to receive information from a network entity 105 also discloses that a first node is configured to receive information from a second node.

[0053] In some examples, network entities 105 may communicate with the core network 130, or with one another, or both. For example, network entities 105 may communicate with the core network 130 via one or more backhaul communication links 120 (e.g., in accordance with an SI, N2, N3, or other interface protocol). In some examples, network entities 105 may communicate with one another via a backhaul communication link 120 (e.g., in accordance with an X2, Xn, or other interface protocol) either directly (e.g., directly between network entities 105) or indirectly (e.g., via a core network 130). In some examples, network entities 105 may communicate with one another via a midhaul communication link 162 (e.g., in accordance with a midhaul interface protocol) or a fronthaul communication link 168 (e.g., in accordance with a fronthaul interface protocol), or any combination thereof. The backhaul communication links 120, midhaul communication links 162, or fronthaul communication links 168 may be or include one or more wired links (e.g., an electrical link, an optical fiber link), one or more wireless links (e.g., a radio link, a wireless optical link), among other examples or various combinations thereof. A UE 115 may communicate with the core network 130 via a communication link 155.

[0054] One or more of the network entities 105 described herein may include or may be referred to as a base station 140 (e.g., a base transceiver station, a radio base station, an NR base station, an access point, a radio transceiver, aNodeB, an eNodeB(eNB), a next-generation NodeB or a giga-NodeB (either of which may be referred to as a gNB), a 5G NB, a next-generation eNB (ng-eNB), a Home NodeB, a Home eNodeB, or other suitable terminology ). In some examples, a network entity 105 (e.g., a base station 140) may be implemented in an aggregated (e.g., monolithic, standalone) base station architecture, which may be configured to utilize a protocol stack that is physically or logically integrated within a single network entity 105 (e.g., a single RAN node, such as a base station 140).

[0055] In some examples, a network entity 105 may be implemented in a disaggregated architecture (e.g., a disaggregated base station architecture, a disaggregated RAN architecture), which may be configured to utilize a protocol stack that is physically or logically distributed among two or more network entities 105, such as an integrated access backhaul (I AB) network, an open RAN (O-RAN) (e.g., a network configuration sponsored by the O-RAN Alliance), or a virtualized RAN (vRAN) (e.g., a cloud RAN (C-RAN)). For example, a network entity 105 may include one or more of a central unit (CU) 160, a distributed unit (DU) 165, a radio unit (RU) 170, a RAN Intelligent Controller (RIC) 175 (e.g., a Near-Real Time RIC (Near-RT RIC), aNon-Real Time RIC (Non-RT RIC)), a Service Management and Orchestration (SMO) 180 system, or any combination thereof. An RU 170 may also be referred to as a radio head, a smart radio head, a remote radio head (RRH), a remote radio unit (RRU), or a transmission reception point (TRP). One or more components of the network entities 105 in a disaggregated RAN architecture may be co-located, or one or more components of the network entities 105 may be located in distributed locations (e.g., separate physical locations). In some examples, one or more network entities 105 of a disaggregated RAN architecture may be implemented as virtual units (e.g., a virtual CU (VCU), a virtual DU (VDU), a virtual RU (VRU)).

[0056] The split of functionality between a CU 160, a DU 165, and an RU 170 is flexible and may support different functionalities depending on which functions (e.g., network layer functions, protocol layer functions, baseband functions, RF functions, and any combinations thereof) are performed at a CU 160, a DU 165, or an RU 170. For example, a functional split of a protocol stack may be employed between a CU 160 and a DU 165 such that the CU 160 may support one or more layers of the protocol stack and the DU 165 may support one or more different layers of the protocol stack. In someexamples, the CU 160 may host upper protocol layer (e.g., layer 3 (L3), layer 2 (L2)) functionality and signaling (e.g., Radio Resource Control (RRC), service data adaption protocol (SDAP), Packet Data Convergence Protocol (PDCP)). The CU 160 may be connected to one or more DUs 165 or RUs 170, and the one or more DUs 165 or RUs 170 may host lower protocol layers, such as layer 1 (LI) (e.g., physical (PHY) layer) or L2 (e.g., radio link control (RLC) layer, medium access control (MAC) layer) functionality and signaling, and each be at least partially controlled by the CU 160. Additionally, or alternatively, a functional split of the protocol stack may be employed between a DU 165 and an RU 170 such that the DU 165 may support one or more layers of the protocol stack and the RU 170 may support one or more different layers of the protocol stack. The DU 165 may support one or multiple different cells (e.g., via one or more RUs 170). In some cases, a functional split between a CU 160 and a DU 165, or between a DU 165 and an RU 170 may be within a protocol layer (e.g., some functions for a protocol layer may be performed by one of a CU 160, a DU 165, or an RU 170, while other functions of the protocol layer are performed by a different one of the CU 160, the DU 165, or the RU 170). A CU 160 may be functionally split further into CU control plane (CU-CP) and CU user plane (CU-UP) functions. A CU 160 may be connected to one or more DUs 165 via a midhaul communication link 162 (e.g., Fl, Fl-c, Fl-u), and a DU 165 may be connected to one or more RUs 170 via a fronthaul communication link 168 (e.g., open fronthaul (FH) interface). In some examples, a midhaul communication link 162 or a fronthaul communication link 168 may be implemented in accordance with an interface (e.g., a channel) between layers of a protocol stack supported by respective network entities 105 that are in communication via such communication links.

[0057] In wireless communications systems (e.g., wireless communications system 100), infrastructure and spectral resources for radio access may support wireless backhaul link capabilities to supplement wired backhaul connections, providing an IAB network architecture (e g., to a core network 130). In some cases, in an TAB network, one or more network entities 105 (e.g., IAB nodes 104) may be partially controlled by each other. One or more IAB nodes 104 may be referred to as a donor entity or an IAB donor. One or more DUs 165 or one or more RUs 170 may be partially controlled by one or more CUs 160 associated with a donor network entity 105 (e.g., a donor basestation 140). The one or more donor network entities 105 (e.g., TAB donors) may be in communication with one or more additional network entities 105 (e.g., IAB nodes 104) via supported access and backhaul links (e.g., backhaul communication links 120). IAB nodes 104 may include an IAB mobile termination (IAB-MT) controlled (e.g., scheduled) by DUs 165 of a coupled IAB donor. An IAB-MT may include an independent set of antennas for relay of communications with UEs 115, or may share the same antennas (e.g., of an RU 170) of an IAB node 104 used for access via the DU 165 of the IAB node 104 (e.g., referred to as virtual IAB-MT (vIAB-MT)). In some examples, the IAB nodes 104 may include DUs 165 that support communication links with additional entities (e.g., IAB nodes 104, UEs 115) within the relay chain or configuration of the access network (e.g., dow nstream). In such cases, one or more components of the disaggregated RAN architecture (e.g., one or more IAB nodes 104 or components of IAB nodes 104) may be configured to operate according to the techniques described herein.

[0058] In the case of the techniques described herein applied in the context of a disaggregated RAN architecture, one or more components of the disaggregated RAN architecture may be configured to support discovery reference signal window configuration for sidelink as described herein. For example, some operations described as being performed by a UE 115 or a network entity 105 (e.g., a base station 140) may additionally, or alternatively, be performed by one or more components of the disaggregated RAN architecture (e.g., IAB nodes 104, DUs 165, CUs 160, RUs 170, RIC 175, SMO 180).

[0059] A UE 115 may 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 UE 115 may 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 UE 115 may include or be referred to as a wireless local loop (WLL) station, an Internet of Things (loT) device, an Internet of Everything (loE) device, or a machine type communications (MTC) device, among other examples, which may beimplemented in various objects such as appliances, or vehicles, meters, among other examples.

[0060] The UEs 115 described herein may be able to communicate with various ty pes of devices, such as other UEs 115 that may sometimes act as relays as well as the network entities 105 and the network equipment including macro eNBs or gNBs, small cell eNBs or gNBs, or relay base stations, among other examples, as shown in FIG. 1.

[0061] The UEs 115 and the network entities 105 may wirelessly communicate with one another via one or more communication links 125 (e.g., an access link) using resources associated with one or more carriers. The term “carrier” may refer to a set of RF spectrum resources having a defined phy sical layer structure for supporting the communication links 125. For example, a carrier used for a communication link 125 may include a portion of a RF spectrum band (e.g., a bandwidth part (BWP)) that is operated according to one or more phy sical layer channels for a given radio access technology (e.g., LTE, LTE-A, LTE-A Pro, NR). Each physical layer channel may carry acquisition signaling (e.g., synchronization signals, system information), control signaling that coordinates operation for the carrier, user data, or other signaling. The wireless communications system 100 may support communication with a UE 115 using carrier aggregation or multi-carrier operation. A UE 115 may be configured with multiple downlink component earners and one or more uplink component earners according to a carrier aggregation configuration Carrier aggregation may be used with both frequency division duplexing (FDD) and time division duplexing (TDD) component carriers. Communication between a network entity 105 and other devices may refer to communication between the devices and any portion (e.g., entity , subentity) of a network entity 105. For example, the terms “transmitting,” “receiving,” or “communicating,” when referring to a network entity 105, may refer to any portion of a network entity 105 (e.g., a base station 140, a CU 160, a DU 165, a RU 170) of a RAN communicating with another device (e.g., directly or via one or more other network entities 105).

[0062] The communication links 125 shown in the wireless communications system 100 may include downlink transmissions (e.g., forward link transmissions) from a network entity 105 to a UE 115, uplink transmissions (e.g., return link transmissions) from a UE 115 to a network entity 105, or both, among other configurations oftransmissions. Carriers may carry downlink or uplink communications (e g., in an FDD mode) or may be configured to carry downlink and uplink communications (e.g., in a TDD mode).

[0063] Signal waveforms transmitted via a carrier may be made up of multiple subcarriers (e.g., using multi-carrier modulation (MCM) techniques such as orthogonal frequency division multiplexing (OFDM) or discrete Fourier transform spread OFDM (DFT-S-OFDM)). In a system employing MCM techniques, a resource element may refer to resources of one symbol period (e.g., a duration of one modulation symbol) and one subcarrier, in which case the symbol period and subcarrier spacing may be inversely related. The quantity of bits carried by each resource element may depend on the modulation scheme (e.g., the order of the modulation scheme, the coding rate of the modulation scheme, or both), such that a relatively higher quantity of resource elements (e.g., in a transmission duration) and a relatively higher order of a modulation scheme may correspond to a relatively higher rate of communication. A wireless communications resource may refer to a combination of an RF spectrum resource, a time resource, and a spatial resource (e.g., a spatial layer, a beam), and the use of multiple spatial resources may increase the data rate or data integrity for communications with a UE 115.

[0064] The time intervals for the network entities 105 or the UEs 115 may be expressed in multiples of a basic time unit which may, for example, refer to a sampling period of Ts= l / fmax' f) seconds, for which fmaxmay represent a supported subcarn er spacing, and Nf may represent a supported discrete Founer transform (DFT) size. Time intervals of a communications resource may be organized according to radio frames each having a specified duration (e.g., 10 milliseconds (ms)). Each radio frame may be identified by a system frame number (SFN) (e.g., ranging from 0 to 1023).

[0065] Each frame may include multiple consecutively numbered subframes or slots, and each subframe or slot may have the same duration. In some examples, a frame may be divided (e.g., in the time domain) into subframes, and each subframe may be further divided into a quantity of slots. Alternatively, each frame may include a variable quantity of slots, and the quantity of slots may depend on subcarrier spacing. Each slot may include a quantity of symbol periods (e.g., depending on the length of the cyclicprefix prepended to each symbol period). Tn some wireless communications systems TOO, a slot may further be divided into multiple mini-slots associated with one or more symbols. Excluding the cyclic prefix, each symbol period may be associated with one or more (e.g., Nr) sampling periods. The duration of a symbol period may depend on the subcarrier spacing or frequency band of operation.

[0066] A subframe, a slot, a mini-slot, or a symbol may be the smallest scheduling unit (e.g., in the time domain) of the wireless communications system 100 and may be referred to as a transmission time interval (TTI). In some examples, the TTI duration (e.g., a quantity of symbol periods in a TTI) may be variable. Additionally, or alternatively, the smallest scheduling unit of the wireless communications system 100 may be dynamically selected (e.g., in bursts of shortened TTIs (sTTIs)).

[0067] Physical channels may be multiplexed for communication using a carrier according to various techniques. A physical control channel and a physical data channel may be multiplexed for signaling via a downlink earner, for example, using one or more of time division multiplexing (TDM) techniques, frequency division multiplexing (FDM) techniques, or hybrid TDM-FDM techniques. A control region (e.g., a control resource set (CORESET)) for a physical control channel may be defined by a set of symbol periods and may extend across the system bandwidth or a subset of the system bandwidth of the carrier. One or more control regions (e.g., CORESETs) may be configured for a set of the UEs 115. For example, one or more of the UEs 115 may monitor or search control regions for control information according to one or more search space sets, and each search space set may include one or multiple control channel candidates in one or more aggregation levels arranged in a cascaded manner. An aggregation level for a control channel candidate may refer to an amount of control channel resources (e.g., control channel elements (CCEs)) associated with encoded information for a control information format having a given payload size. Search space sets may include common search space sets configured for sending control information to multiple UEs 115 and UE-specific search space sets for sending control information to a specific UE 115.

[0068] A network entity 105 may provide communication coverage via one or more cells, for example a macro cell, a small cell, a hot spot, or other types of cells, or anycombination thereof. The term “cell” may refer to a logical communication entity' used for communication with a network entity 105 (e.g., using a carrier) and may be associated with an identifier for distinguishing neighboring cells (e.g., a physical cell identifier (PCID), a virtual cell identifier (VCID), or others). In some examples, a cell also may refer to a coverage area 110 or a portion of a coverage area 110 (e.g., a sector) over which the logical communication entity operates. Such cells may range from smaller areas (e.g., a structure, a subset of structure) to larger areas depending on various factors such as the capabilities of the network entity 105. For example, a cell may be or include a building, a subset of a building, or exterior spaces between or overlapping with coverage areas 110, among other examples.

[0069] A macro cell generally covers a relatively large geographic area (e.g., several kilometers in radius) and may allow unrestricted access by the UEs 115 with service subscriptions with the network provider supporting the macro cell. A small cell may be associated with a lower-powered network entity 105 (e.g., a lower-powered base station 140), as compared with a macro cell, and a small cell may operate using the same or different (e.g., licensed, unlicensed) frequency bands as macro cells. Small cells may provide unrestricted access to the UEs 115 with service subscriptions with the network provider or may provide restricted access to the UEs 115 having an association with the small cell (e.g., the UEs 115 in a closed subscriber group (CSG), the UEs 115 associated with users in a home or office). A network entity 105 may support one or multiple cells and may also support communications via the one or more cells using one or multiple component carriers.

[0070] In some examples, a carrier may support multiple cells, and different cells may be configured according to different protocol types (e.g., MTC, narrowband loT (NB-IoT), enhanced mobile broadband (eMBB)) that may provide access for different types of devices.

[0071] In some examples, a network entity 105 (e.g., a base station 140, an RU 170) may be movable and therefore provide communication coverage for a moving coverage area 110. In some examples, different coverage areas 110 associated with different technologies may overlap, but the different coverage areas 110 may be supported by the same network entity 105. In some other examples, the overlapping coverage areas 110 associated with different technologies may be supported by different network entities105. The wireless communications system 100 may include, for example, a heterogeneous network in which different types of the network entities 105 provide coverage for various coverage areas 110 using the same or different radio access technologies.

[0072] The wireless communications system 100 may support synchronous or asynchronous operation. For synchronous operation, network entities 105 (e.g., base stations 140) may have similar frame timings, and transmissions from different network entities 105 may be approximately aligned in time. For asynchronous operation, network entities 105 may have different frame timings, and transmissions from different network entities 105 may, in some examples, not be aligned in time. The techniques described herein may be used for either synchronous or asynchronous operations.

[0073] Some UEs 115, such as MTC or loT devices, may be low cost or low complexity devices and may provide for automated communication between machines (e.g., via Machine-to-Machine (M2M) communication). M2M communication or MTC may refer to data communication technologies that allow devices to communicate with one another or a network entity 105 (e.g., a base station 140) without human intervention. In some examples, M2M communication or MTC may include communications from devices that integrate sensors or meters to measure or capture information and relay such information to a central server or application program that uses the information or presents the information to humans interacting with the application program. Some UEs 115 may be designed to collect information or enable automated behavior of machines or other devices. Examples of applications for MTC devices include smart metering, inventory monitoring, water level monitoring, equipment monitoring, healthcare monitoring, wildlife monitoring, weather and geological event monitoring, fleet management and tracking, remote security sensing, physical access control, and transaction-based business charging.

[0074] The wireless communications system 100 may be configured to support ultra-reliable communications or low-latency communications, or various combinations thereof. For example, the wireless communications system 100 may be configured to support ultra-reliable low-latency communications (URLLC). The UEs 115 may be designed to support ultra-reliable, low-latency, or critical functions. Ultra-reliable communications may include private communication or group communication and maybe supported by one or more services such as push-to-talk, video, or data. Support for ultra-reliable, low-latency functions may include prioritization of services, and such services may be used for public safety or general commercial applications. The terms ultra-reliable, low-latency, and ultra-reliable low-latency may be used interchangeably herein.

[0075] In some examples, a UE 115 may be configured to support communicating directly with other UEs 115 via a device-to-device (D2D) communication link 135 (e.g., in accordance with a peer-to-peer (P2P), D2D, or sidelink protocol). In some examples, one or more UEs 115 of a group that are performing D2D communications may be within the coverage area 110 of a network entity 105 (e.g., a base station 140, an RU 170), which may support aspects of such D2D communications being configured by (e.g., scheduled by) the network entity 105. In some examples, one or more UEs 115 of such a group may be outside the coverage area 110 of a network entity 105 or may be otherwise unable to or not configured to receive transmissions from a network entity 105. In some examples, groups of the UEs 115 communicating via D2D communications may support a one-to-many (1:M) system in which each UE 115 transmits to each of the other UEs 115 in the group. In some examples, a network entity 105 may facilitate the scheduling of resources for D2D communications. In some other examples, D2D communications may be carried out between the UEs 115 without an involvement of a network entity 105.

[0076] In some systems, a D2D communication link 135 may be an example of a communication channel, such as a sidelink communication channel, between vehicles (e.g., UEs 115). In some examples, vehicles may communicate using vehicle-to- everything (V2X) communications, vehicle-to-vehicle (V2V) communications, or some combination of these. A vehicle may signal information related to traffic conditions, signal scheduling, weather, safety, emergencies, or any other information relevant to a V2X system. In some examples, vehicles in a V2X system may communicate with roadside infrastructure, such as roadside units, or with the network via one or more network nodes (e.g., network entities 105, base stations 140, RUs 170) using vehicle-to- network (V2N) communications, or with both.

[0077] The core network 130 may provide user authentication, access authorization, tracking, Internet Protocol (IP) connectivity, and other access, routing, or mobilityfunctions. The core network 130 may be an evolved packet core (EPC) or 5G core (5GC), which may include at least one control plane entity that manages access and mobility (e.g., a mobility management entity (MME), an access and mobility management function (AMF)) and at least one user plane entity that routes packets or interconnects to external networks (e.g., a serving gateway (S-GW), a Packet Data Network (PDN) gateway (P-GW), or a user plane function (UPF)). The control plane entity may manage non-access stratum (NAS) functions such as mobility, authentication, and bearer management for the UEs 115 served by the network entities 105 (e.g., base stations 140) associated with the core network 130. User IP packets may be transferred through the user plane entity, which may provide IP address allocation as well as other functions. The user plane entity may be connected to IP services 150 for one or more network operators. The IP services 150 may include access to the Internet, Intranet(s), an IP Multimedia Subsystem (IMS), or a Packet-Switched Streaming Service.

[0078] The wireless communications system 100 may operate using one or more frequency bands, which may be in the range of 300 megahertz (MHz) to 300 gigahertz (GHz). Generally, the region from 300 MHz to 3 GHz is known as the ultra-high frequency (UHF) region or decimeter band because the wavelengths range from approximately one decimeter to one meter in length. UHF waves may be blocked or redirected by buildings and environmental features, which may be referred to as clusters, but the waves may penetrate structures sufficiently for a macro cell to provide service to the UEs 115 located indoors. Communications using UHF waves may be associated with smaller antennas and shorter ranges (e.g., less than 100 kilometers) compared to communications using the smaller frequencies and longer waves of the high frequency (HF) or very high frequency (VHF) portion of the spectrum below 300 MHz.

[0079] The wireless communications system 100 may utilize both licensed and unlicensed RF spectrum bands. For example, the wireless communications system 100 may employ License Assisted Access (LAA), LTE-Unlicensed (LTE-U) radio access technology, or NR technology using an unlicensed band such as the 5 GHz industrial, scientific, and medical (ISM) band. While operating using unlicensed RF spectrum bands, devices such as the network entities 105 and the UEs 115 may employ carriersensing for collision detection and avoidance. Tn some examples, operations using unlicensed bands may be based on a carrier aggregation configuration in conjunction with component carriers operating using a licensed band (e.g., LAA). Operations using unlicensed spectrum may include downlink transmissions, uplink transmissions, P2P transmissions, or D2D transmissions, among other examples.

[0080] A network entity 105 (e.g., a base station 140, an RU 170) or a UE 115 may be equipped with multiple antennas, which may be used to employ techniques such as transmit diversity, receive diversity, multiple-input multiple-output (MIMO) communications, or beamforming. The antennas of a network entity 105 or a UE 115 may be located within one or more antenna arrays or antenna panels, which may support MIMO operations or transmit or receive beamforming. For example, one or more base station antennas or antenna arrays may be co-located at an antenna assembly, such as an antenna tower. In some examples, antennas or antenna arrays associated with a network entity 105 may be located at diverse geographic locations. A network entity' 105 may include an antenna array with a set of rows and columns of antenna ports that the network entity 105 may use to support beamforming of communications with a UE 115. Likewise, a UE 115 may include one or more antenna arrays that may support various MIMO or beamforming operations. Additionally, or alternatively, an antenna panel may support RF beamforming for a signal transmitted via an antenna port.

[0081] The network entities 105 or the UEs 115 may use MIMO communications to exploit multipath signal propagation and increase spectral efficiency by transmitting or receiving multiple signals via different spatial layers. Such techniques may be referred to as spatial multiplexing. The multiple signals may, for example, be transmitted by the transmitting device via different antennas or different combinations of antennas. Likewise, the multiple signals may be received by the receiving device via different antennas or different combinations of antennas. Each of the multiple signals may be referred to as a separate spatial stream and may carry information associated with the same data stream (e.g., the same codeword) or different data streams (e.g., different codewords). Different spatial layers may be associated with different antenna ports used for channel measurement and reporting. MIMO techniques include single-user MIMO (SU-MIMO), for which multiple spatial layers are transmitted to the same receivingdevice, and multiple-user MTMO (MU-MIMO), for which multiple spatial layers are transmitted to multiple devices.

[0082] Beamforming, which may also be referred to as spatial fdtering, directional transmission, or directional reception, is a signal processing technique that may be used at a transmitting device or a receiving device (e.g., a network entity 105, a UE 115) to shape or steer an antenna beam (e.g., a transmit beam, a receive beam) along a spatial path between the transmitting device and the receiving device. Beamforming may be achieved by combining the signals communicated via antenna elements of an antenna array such that some signals propagating along particular orientations with respect to an antenna array experience constructive interference while others experience destructive interference. The adjustment of signals communicated via the antenna elements may include a transmitting device or a receiving device applying amplitude offsets, phase offsets, or both to signals carried via the antenna elements associated with the device. The adjustments associated with each of the antenna elements may be defined by a beamforming weight set associated with a particular orientation (e g., with respect to the antenna array of the transmitting device or receiving device, or with respect to some other orientation).

[0083] A network entity 105 or a UE 115 may use beam sweeping techniques as part of beamforming operations. For example, a network entity 105 (e.g., a base station 140, an RU 170) may use multiple antennas or antenna arrays (e g., antenna panels) to conduct beamforming operations for directional communications with a UE 115. Some signals (e.g., synchronization signals, reference signals, beam selection signals, or other control signals) may be transmitted by a network entity 105 multiple times along different directions. For example, the network entity' 105 may transmit a signal according to different beamforming weight sets associated with different directions of transmission. Transmissions along different beam directions may be used to identify (e.g., by a transmitting device, such as a network entity 105, or by a receiving device, such as a UE 115) a beam direction for later transmission or reception by the network entity 105.

[0084] Some signals, such as data signals associated with a particular receiving device, may be transmitted by transmitting device (e.g., a transmitting network entity 105, a transmitting UE 115) along a single beam direction (e.g., a direction associatedwith the receiving device, such as a receiving network entity 105 or a receiving UE 11 ). In some examples, the beam direction associated with transmissions along a single beam direction may be determined based on a signal that was transmitted along one or more beam directions. For example, a UE 115 may receive one or more of the signals transmitted by the network entity 105 along different directions and may report to the network entity 105 an indication of the signal that the UE 115 received with a highest signal quality or an otherwise acceptable signal quality.

[0085] In some examples, transmissions by a device (e.g., by a network entity 105 or a UE 115) may be performed using multiple beam directions, and the device may use a combination of digital precoding or beamforming to generate a combined beam for transmission (e.g., from a network entity 105 to a UE 115). The UE 115 may report feedback that indicates precoding weights for one or more beam directions, and the feedback may correspond to a configured set of beams across a system bandwidth or one or more sub-bands. The network entity 105 may transmit a reference signal (e.g., a cell-specific reference signal (CRS), a channel state information reference signal (CSI- RS)), which may be precoded or unprecoded. The UE 115 may provide feedback for beam selection, which may be a precoding matrix indicator (PMI) or codebook-based feedback (e.g., a multi-panel type codebook, a linear combination type codebook, a port selection type codebook). Although these techniques are described with reference to signals transmitted along one or more directions by a network entity 105 (e.g., a base station 140, an RU 170), a UE 115 may employ similar techniques for transmitting signals multiple times along different directions (e.g., for identifying a beam direction for subsequent transmission or reception by the UE 115) or for transmitting a signal along a single direction (e.g., for transmitting data to a receiving device).

[0086] A receiving device (e.g., a UE 115) may perform reception operations in accordance with multiple receive configurations (e.g., directional listening) when receiving various signals from a receiving device (e.g., a network entity 105), such as synchronization signals, reference signals, beam selection signals, or other control signals. For example, a receiving device may perform reception in accordance with multiple receive directions by receiving via different antenna subarrays, by processing received signals according to different antenna subarrays, by receiving according to different receive beamforming weight sets (e.g., different directional listening weightsets) applied to signals received at multiple antenna elements of an antenna array, or by processing received signals according to different receive beamforming weight sets applied to signals received at multiple antenna elements of an antenna array, any of which may be referred to as “listening” according to different receive configurations or receive directions. In some examples, a receiving device may use a single receive configuration to receive along a single beam direction (e.g., when receiving a data signal). The single receive configuration may be aligned along a beam direction determined based on listening according to different receive configuration directions (e.g., a beam direction determined to have a highest signal strength, highest signal -to- noise ratio (SNR), or otherwise acceptable signal quality based on listening according to multiple beam directions).

[0087] In some examples of the wireless communication system 100, the one or more UEs 115 may share S-SSBs to support synchronization with the network entity 105 by the UEs 115 that receive the S-SSBs. The transmissions of these S-SSBs may be performed during a configured DRS window. For example, a first UE 115 that is in coverage of a trusted synchronization source (e.g., the network entity 105) may receive synchronization information (e.g., an SSB) from the network entity 105. To benefit neighboring UEs 115 that are not in the coverage of the network entity 105 (e.g., the UEs 115 have not received the synchronization information), the first UE 115 may become a S-SSB transmitter (e.g., a first syncRef node) and transmit the S-SSBs containing the synchronization information from the network entity to the other UEs 115.

[0088] A second UE 115, which may not be in coverage of the network entity, may receive these S-SSBs from the first syncRef node and use these S-SSBs to synchronize with the network entity . In some examples, the second UE 115 may determine to also transmit S-SSBs (becoming a second syncRef node) to a third UE 115. As such, the synchronization information may keep propagating through the system. However, the UEs 115 may have half-duplex limitations that inhibit efficient S-SSB transmission and reception. Additionally, due to LBT uncertainty in the system, the syncRef nodes may use additional opportunities to transmit the S-SSBs.

[0089] To support S-SSB transmission and reception in the wireless communications sy stem 100, which may include the half-duplex UEs 115, techniquesdescribed herein support configurations of one or more DRS windows that include multiple S-SSB transmission opportunities and multiple S-SSB reception opportunities. In one example, two DRS windows may be configured such that a first DRS window includes the multiple S-SSB reception opportunities (resources), and a second DRS window includes the multiple S-SSB transmission opportunities. The two DRS windows may be contiguous and non-overlapping or time combinational (e.g., interleaved). In another example, one DRS window may be configured to include the S- SSB transmission opportunities and the S-SSB transmission reception opportunities (e.g., in an interleaved pattern).

[0090] Techniques described herein also support a configuration for a single DRS window that includes a S-SSB transmission opportunity, an S-SSB reception opportunity, and a set of additional S-SSB opportunities that may be used for transmission or reception. In some cases, to prevent timing issues, a S-SSB receiving UE 115 (e.g., a second syncRef node) may monitor for the S-SSB from a first syncRef node before it starts S-SSB transmission, therefore forgoing transmission opportunities until the S-SSB transmission is likely to be accurate.

[0091] FIG. 2 illustrates an example of a wireless communications system 200 that supports discovery reference signal window configuration for sidelink in accordance with one or more aspects of the present disclosure. In some examples, the wireless communications system 200 may implement aspects of the wireless communications system 100 or may be implemented by aspects of the wireless communications system 100. For example, the wireless communications system 200 may include a UE 115-a and a network entity 105-a, which may be examples of corresponding devices described herein.

[0092] In some implementations of the wireless communications system 200, the network entity 105-a may have a coverage area 205, which may be an example of the coverage area 110 as described with respect to FIG. 1. The UE 115-a may reside inside of the coverage area 205, and the network entity 105-a may communicate and share information with the UE 115-a via a communication link 125-a (e.g., an access link). In some examples, the network entity 105-a may transmit synchronization information (e.g., in an SSB message) to the UE 115-a via the communication link 125-a

[0093] Tn some cases, the UE 1 15-a may determine that neighboring UEs 1 15 are not receiving synchronization information and determine to transmit an S-SSB to the neighboring UEs 115 (e.g., a UE 115-b and a UE 115-c). For example, the UE 115-a may have direct access to the timing and synchronization information from the network entity 105-a (e.g., a synchronization source), and therefore may be considered a first syncRef node (a node that has direct access to the timing / synchronization information). In such examples, the UE 115-a may determine to become the S-SSB transmitter (e.g., the first syncRef node) and transmit the S-SSBs to support the neighboring UEs (e.g., UE 115-b). In doing so, the synchronization information may propagate through the wireless communications system 200.

[0094] According to some configurations, a quantity of S-SSB instances within one S-SSB period may be limited. In frequency one (FR1), when a subcarrier spacing is 15 kHz, the quantity of S-SSB instances or slots may be one (e.g., K = 1). In FR1 with a 30 kHz subcarrier spacing, the quantity of S-SSB instances or slots be one or two (e.g., K = 1 or K = 2). However, because a UE 115 is to perform and clear a LBT procedure (e.g., LBT uncertainty) before transmitting an S-SSB, the S-SSB transmitting node may be configured with more opportunities to transmit an S-SSB. As such, as illustrated in FIG. 2, a UE 115 may be configured with the DRS window 215 starting at an S-SSB instance, which supports the increase of S-SSB candidate locations for each S-SSB instance. A DRS window (e.g., DRS window 215) may be defined starting from the S- SSB instance, and the node may be configured to transmit S-SSBs during up to K S- SSB slots within L candidate locations after clearing LBT. For example, a node transmits during up to K S-SSB slots within an L number of S-SSB candidate locations 220 after clearing the LBT (e.g., =4 in £=10 candidate locations or K = 8 in L = 20 candidate locations).

[0095] According to the configuration of the DRS window 215, an S-SSB transmission 225 may be attempted at a first S-SSB candidate locations 220, which is the nominal S-SSB candidate locations 220. However, the LBT may fail at the nominal S-SSB candidate location 220 which may prevent transmission of the S-SSB. As such, the configuration of multiple S-SSB candidate locations 220 may support multiple attempts at the S-SSB transmission 225. The UE 115-a may attempt LBT during the S- SSB candidate locations 220 of the DRS window 215 and transmit the S-SSBs based onclearing LBT. With this introduction of multiple S-SSB candidate locations 220 around each S-SSB instance (e.g., the DRS window starting from each S-SSB instance) the LBT uncertainty in the system may be addressed by supporting multiple locations for performing LBT procedures and multiple locations for S-SSB transmission. In cases when the LBT is successful, downstream nodes (e.g., the UE 115-b) may rely on the first syncRef node (e.g., the UE 115 -a) as a timing reference for synchronization with the network entity 105 -a.

[0096] In some examples of the present disclosure, the UE 115-b may determine that the UE 115-c does not have the timing information sent from the first syncRef node (e.g., the UE 115-a). For example, the UE 115-b may detect that the third UE (e.g., the UE 115-c) is a threshold distance away from the UE 115-b and the UE 115-a such that the UE 115-c is not in the coverage area 205 of the network entity 105-a. The threshold distance may be a distance such that the UE 115-c may not have a communication link with the trusted synchronization source (e.g., the network entity 105-a) and may also not have a communication link with the first syncRef node (e.g., the UE 1 L5-a), which may be used by the UE 115-b as a timing reference. To prevent timing and synchronization issues, the second UE 115-b may attempt to become a S-SSB transmitter (e.g., a second syncRef node) based on a threshold or criteria, such as a distance threshold or a reference signal received power (RSRP) threshold. However, the UE 115-b may be limited by half-duplex constraints, and therefore is not able to monitor for S-SSB messages from the first syncRef node and transmit S-SSB messages to the UE 115-c during a same set of resources.

[0097] Due to the half-duplex nature of the nodes (e.g., the UE 115) in the system, at least two orthogonal S-SSB timing configurations may be defined. For example, one timing allocation (e.g., a first sl-SSB-TimeAllocation) is defined for receiving the S-SSB from a selected syncRef node (e.g., the first syncRef node or the UE 115-a), and a second timing allocation (e.g., a second sl-SSB-TimeAllocatiori) is defined for transmitting the S-SSB. Each timing allocation (e.g., sl-SSB-TimeAllocation) may specify a slot offset (e.g., sl-TimeOffsetSSB) from the period (e.g., 160 ms period), a slot interval (e.g., sl-Timelnterval) between the S-SSBs in the period (e.g., a period inbetween S-SSB candidate locations 220), and a quantity of S-SSB transmitting instances within one period (e.g., sl-NumSSB-WithinPeriod). However, such configurations mayresult in LBT uncertainty, as one S-SSB candidate location exists for S-SSB transmission by a particular node.

[0098] As described herein, to limit or reduce LBT uncertainty, multiple S-SSB candidate slots around each candidate instance are introduced. Further, to address halfduplex operations by syncRef nodes, techniques describe herein support configurations for multiple S-SSB transmission opportunities and multiple S-SSB reception opportunities in one or more DRS windows, such as DRS window 215. Further, as described herein, the one or more DRS windows may be configured as non-overlapping or overlapping windows (with interleaved resources). These various configurations may support reduced resource overhead and / or reduced UE complexity. These DRS window configurations are described in further detail with respect to FIGs. 3A, 3B, and 4.

[0099] FIG. 3 A illustrates examples of resource diagrams 300 and 301 that support discovery reference signal window configuration for sidelink in accordance with one or more aspects of the present disclosure. In some examples, the resource diagrams 300 and 301 may be implemented by aspects of the wireless communications system 100 and 200. For example, the resource diagrams 300 and 301 may be implemented by the UE 115 and the network entity 105, which may be examples of corresponding devices described herein.

[0100] Aspects of the present disclosure may support various configurations of one or more DRS windows in the network. In some examples, at least two DRS windows may allow for allocation of two sets of S-SSB time resources (e.g., one for S-SSB transmission and one for S-SSB candidate monitoring). A set of S-SSB occasions for monitoring for a S-SSB transmission from a syncRef node (e.g., a S-SSB transmitter) may be associated with a reception DRS window (e.g., a reception DRS window 310 or a reception DRS window 330) and a set of S-SSB occasions for S-SSB transmission with multiple candidate locations may be associated with a transmission DRS window (e.g., a transmission DRS window 315 and a transmission DRS window 335). In some examples, the configuration of the DRS window (e.g., the reception DRS window or the transmission DRS window) may include a quantity of S-SSB occasions and a slot interval between the S-SSB occasions. In the defined timing allocation configuration (e.g., sl-SSB-TimeAllocatiori), the S-SSB candidate slots (e.g., occasions) may be defined including and after the S-SSB instances. In some cases, the slot intervalbetween the S-SSB candidate slots may be set to zero if it is determined that the S-SSB candidate slots should be continuous.

[0101] In accordance with aspects of the present disclosure, the resource diagram 300 illustrates a DRS configuration that includes two DRS windows in which the reception DRS window 310 and the transmission DRS window 315 do not overlap. For example, the S-SSB candidate slot interval for both the reception DRS window 310 and the transmission DRS window 315 may be set to zero to allow the S-SSB candidate slots to be continuous. In some examples, the slot interval may be set to zero to shorten the length of the DRS window (e.g., the reception DRS window 310 and / or the transmission DRS window 315). As such, a receiver may not monitor for S-SSB candidates for a prolonged amount of time and may minimize transmission and reception switching. It should be understood that the SSB occasions of one or more of the reception DRS window 310 and the transmission DRS window 315 may be discontinuous (e.g., positioned with intervening slot intervals).

[0102] As illustrated in resource diagram 300, the transmission DRS window 315 may start after completion of the reception DRS window 310. In doing so, a UE may wait until the UE has received at least a portion of S-SSB messages in the reception DRS window 310 before transmitting the S-SSB messages in the transmission DRS window 315.

[0103] The reception DRS window 310 includes multiple S-SSB reception occasions 320 for receiving S-SSB messages. The configuration of multiple reception occasions may support more opportunities to receive S-SSB messages in case of LBT uncertainty at a transmitting node. Additionally, the transmission DRS window 315 may include multiple S-SSB transmission occasions 325 for transmitting S-SSB messages. The inclusion of multiple S-SSB transmission occasions may support more opportunities to clear LBT and transmit S-SSB messages in case of LBT uncertainty. In some cases, the configuration of the transmission DRS window 315 may support transmitting a S-SSB burst in a set of S-SSB transmission occasions (e.g., multiple occasions).

[0104] The resource diagram 300 may be used with a low quantity of the S-SSB reception occasions 320 and the S-SSB transmission occasions 325. As the transmissionDRS window 315 may wait until the completion of the reception DRS window 310, a large quantity of S-SSB reception occasions 320 and S-SSB transmission occasions 325 may cause a large delay in the system. Therefore, the resource diagram 300 provides support for basic reception and transmission between two UEs 115 with a low quantity of S-SSB candidate locations. Further, the resource diagram 300 may support reduced UE complexity, as the UE may not continuously or periodically switch between the S- SSB transmission occasions and the S-SSB reception occasions.

[0105] The resource diagram 301 illustrates a DRS window configuration with two time-combinational DRS windows (e.g., an interleaving pattern). The DRS configuration may include a reception DRS window 330 with multiple S-SSB reception occasions 340 and a transmission DRS window 335 with multiple S-SSB transmission occasions 345. As illustrated, the S-SSB transmission occasions 345 of the transmission DRS window 335 may not overlap with the S-SSB reception occasions 340 of the reception DRS window 330.

[0106] The transmission DRS window 335 of resource diagram 301 may start during the reception DRS window 330. In such implementations, the slot interval 350 (e.g., a separation in the time domain) may be set to be greater than zero. In some cases, the slot interval 350 may be set to be equal to the length of one S-SSB reception occasion 340 or S-SSB transmission occasion 345. For example, during the period of the candidate slot interval 350, the syncRef node may switch between the reception DRS window 330 and the transmission DRS window 335. As such, the syncRef node may not wait until monitoring all of the S-SSB reception occasions 340 from the syncRef UE before the syncRef node starts the transmission DRS window 335.

[0107] The resource diagram 301 may be implemented with a large quantity of the S-SSB reception occasions 340 and the S-SSB transmission occasions 345. Enabling the syncRef node to switch between the reception DRS window 330 and the transmission DRS window 335 support the syncRef node transmitting S-SSB messages after the S- SSB messages are received. However, according to the resource diagram 301, the syncRef node may switch back and forth between the reception DRS window 330 to monitor for S-SSB messages and the transmission DRS window 335 to transmit the received S-SSB messages, which may result in increased UE complexity. In some examples, the LBT process may fail at a S-SSB transmission occasion 345 in thetransmission DRS window 335 and may wait until the next reception DRS window slot (e.g., opportunity in the reception DRS window 330) to attempt the transmission at another S-SSB transmission occasion 345. which may result in delays in communication of synchronization information.

[0108] As illustrated in FIG. 3 A, the reception DRS window 310 and the transmission DRS of the resource diagram 300 and the reception DRS window 330 and the transmission DRS window 335 of the resource diagram 301 may be positioned in different frequency resources. In some examples, the different frequency resources are orthogonal. It should be understood that the respective reception DRS windows and the transmission DRS windows may be positioned in the same or in overlapping frequency resources. Further, the S-SSB transmission occasions and the S-SSB reception occasions of FIG. 3A may correspond to a slot (e.g., the S-SSB reception occasions 320 are respective slots) or may be positioned in portions of respective slots. It should be understood that the S-SSB transmission occasions and the S-SSB reception occasions may correspond to other types of transmission time intervals.

[0109] However, the configurations illustrated in the resource diagrams 300 and 301 may cause large overhead in the network. In some cases, the multiple S-SSB candidate slots in each DRS window may be excluded from the data resource pool. As such, the configuration of multiple orthogonal DRS windows may cause the S-SSB candidate overhead to increase accordingly with the quantity of DRS windows. For example, for the S-SSB candidate slots within one DRS window, the syncRef node may transmit up to K S-SSB slots (e.g., K may equal one) at the earliest slot (e.g., S-SSB candidate opportunity) which clears the LBT procedure. In some cases, if the LBT clears early, the resources of remaining S-SSB transmission opportunities may be un-used.

[0110] FIG. 3B illustrates an example of a resource diagram 302 that supports discovery reference signal window configuration for sidelink in accordance with one or more aspects of the present disclosure. In some examples, the resource diagram 300 may be implemented by aspects of the wireless communications system 100 and 200. For example, the resource diagram 302 may be implemented by the UE 115 and the network entity 105, which may be examples of corresponding devices described herein.

[0111] Tn some examples, one DRS window 355 may be configured and even and odd indexed slots (e.g., occasions) within the DRS window 355 may be associated with two orthogonal S-SSB resources for reception and transmission, respectively. For example, the single DRS window 355 may be a DRS window for both reception and transmission of S-SSB messages (e.g., reception / transmission DRS window). The DRS window 355 may include multiple S-SSB reception occasions (e.g., S-SSB reception occasion 360) and multiple S-SSB transmission occasions (e.g., S-SSB transmission occasion 365). In some examples, the syncRef node may monitor for S-SSB messages in the even index slots (e.g., the S-SSB reception occasions). As such, in the odd index slots (e.g., the S-SSB transmission occasions) the syncRef node may attempt to clear an LBT procedure and transmit the S-SSB messages.

[0112] In some cases, the syncRef node may wait until it receives the S-SSB message and / or until the timing or frequency accuracy (e.g., a synchronization accuracy threshold) is above a threshold (e.g., a synchronization accuracy threshold) before transmitting the S-SSB message in the DRS window 355. Thus, in one example, if the UE does not receive an S-SSB during S-SSB reception occasion 360, then the UE may not use the S-SSB transmission occasion 365 for performing the LBT procedure and / or transmitting an S-SSB. Thereafter, if the UE receives the S-SSB during a subsequent S- SSB reception occasion, the UE may perform LBT and / or transmit the S-SSB during a S-SSB transmission occasion subsequent to the S-SSB reception occasion during which the S-SSB is received. The S-SSB transmission occasions and the S-SSB transmission occasions of FIG. 3B may be positioned in the same or overlapping frequency resources or in different and / or orthogonal frequency resources. As described with respect to FIG. 3 A, the S-SSB transmission occasions and S-SSB reception occasions of FIG. 3B may correspond to a slot (e.g., S-SSB reception occasion 360 is a slot) or may be positioned in portions of a slot. It should be understood that the S-SSB transmission occasions and the S-SSB reception occasions may correspond to other types of transmission time intervals.

[0113] FIG. 4 illustrates an example of a resource diagram 400 that supports discovery reference signal window configuration for sidelink in accordance with one or more aspects of the present disclosure. In some examples, the resource diagram 400 may be implemented by aspects of the wireless communications system 100 and 200.For example, the resource diagram 400 may be implemented by the UE 1 15 and the network entity 105, which may be examples of corresponding devices described herein.

[0114] In accordance with the present disclosure, some implementations may have a single DRS window configuration for both the reception and transmission (e.g., a reception / transmission DRS window 405). In some examples, the reception / transmission DRS window 405 may include a first S-SSB occasion 410, a second S-SSB occasion 415, and a set of additional S-SSB transmission occasions 420. In some cases, the set of additional S-SSB transmission occasions 420 are included to provide additional LBT and S-SSB transmission or reception opportunities for the reception / transmission DRS window 405. For example, the set of additional S-SSB transmission occasions 420 may be dynamically used (e.g., occasions may be used for S-SSB reception or transmission). In some cases, the first S-SSB occasion 410 may be reserved as a transmission S-SSB occasion to transmit the S-SSB message from a syncRef node (e.g., a first syncRef node relied upon for timing and / or synchronization information via the S-SSB message) to a second syncRef node. The second S-SSB occasion may be reserved for transmission of the S-SSB message from the second syncRef node to a neighboring UE 115. In some implementations, the first syncRef node is not to transmit during the second S-SSB occasion and is to wait until after the second S-SSB occasion to attempt to transmit again (e.g., perform another LBT procedure). As such, the second syncRef node may not be allowed to transmit during the first S-SSB occasion. Both the first and the second syncRef node may transmit during occasions of the set of additional S-SSB transmission occasions 420 depending on various conditions, circumstances, or implementations.

[0115] In some other implementations, the resource diagram 400 includes both a reception DRS window and a transmission DRS window. As such, the set of additional S-SSB transmission occasions 420 may be overlapping between the reception DRS window and the transmission DRS window. The first S-SSB occasion 410 may be in the reception DRS window and used to receive a S-SSB message from the first syncRef node and the second S-SSB occasion 415 may be in the transmission DRS window and used for the second syncRef node to transmit the S-SSB message.

[0116] In some examples, both the first syncRef node and second syncRef node may transmit S-SSB messages in the set of additional S-SSB transmission occasions420. However, half-duplex limitations may cause synchronization issues at the UEs. For example, the first syncRef node and the second syncRef node may be transmitting during the same S-SSB occasion of the set of additional S-SSB transmission occasions 420. Therefore, the second syncRef node may not receive the timing and synchronization information (via the S-SSB message) from the first syncRef node due to overlapping transmissions and half-duplex limitations.

[0117] As such, to account for half-duplex limitations, the second syncRef node may determine that a synchronization accuracy (e.g., timing and / or frequency accuracy) is below some threshold (e.g., a synchronization accuracy threshold) and, as such, is to synchronize with the first syncRef node based on a received S-SSB. The second syncRef node may monitor for S-SSB messages from the first syncRef node until the S- SSB message is received and detected in the reception / transmission DRS window 405, before the second syncRef node begins the S-SSB transmission (after clearing LBT). As such, the second syncRef node may forgo any possible transmission opportunities in the reception / transmission DRS window 405 until it receives the S-SSB message, thereby improving synchronization accuracy in a wireless communication system

[0118] In some examples, the second syncRef node may not receive the S-SSB message from the first syncRef node until a first S-SSB occasion 425 of the set of additional S-SSB transmission occasions 420. For example, the transmission of the S- SSB message from the first syncRef node to the second syncRef node during the first S- SSB occasion 410 may not occur due to a LBT failure. As such, the second syncRef node may forgo the transmission opportunity during the second S-SSB occasion 415 and wait until a S-SSB transmission occasion of the set of additional S-SSB transmission occasions 420. The second syncRef node may receive the S-SSB message from the first syncRef node during the first S-SSB occasion 425 of the set of additional S-SSB transmission occasions 420 in the reception / transmission DRS window 405. During the second S-SSB occasion 430 of the set of additional S-SSB transmission occasions 420, the second syncRef node may transmit the S-SSB message (e.g., based on clearing LBT). As such, the second syncRef node may use the set of additional S- SSB transmission occasions 420 to ensure the second syncRef node receives the S-SSB message from the first syncRef node as to support improved synchronization accuracy in the wireless communications system.

[0119] FIG. 5 illustrates an example of a process flow 500 that supports discovery reference window configuration for sidelink in accordance with various aspects of the present disclosure. The process flow 500 may implement aspects of wireless communications systems 100 and 200 or may be implemented by aspects of the wireless communications systems 100 and 200. For example, the process flow 500 may illustrate operations between a UE 115-d, UE 115-e, UE 115-f and a network entity 105-b, which may be examples of corresponding devices described herein. In the following description of the process flow 500, the operations between the UE 115-d, UE 115-e, UE 115-f and the network entity 105-b may be transmitted in a different order than the example order shown, or the operations performed may be performed in different orders or at different times. Some operations may also be omitted from the process flow 500, and other operations may be added to the process flow 500.

[0120] At 505-a, the network entity 105-b may transmit a configuration for one or more DRS windows. The UE 115-d may receive signaling including the configuration for the one or more DRS windows from the network entity 105-b. At 505-b, the UE 115-e may receive a signaling indicating the configuration for the one or more DRS windows. The one or more DRS window configurations may include two or more SSB reception occasions and two or more SSB transmission occasions in accordance with the configuration. In some cases, the UE 115-e may be considered a first UE and the UE 115-d may be considered a second UE. The signaling, at 505-b, that indicates the configuration may be sidelink control signaling (e.g., sidelink control information (SCI)). In some examples, the UE 115-e may relay the configuration for the one or more DRS windows to the UE 115-f using control signaling.

[0121] In some examples, the UE 115-e receiving the signaling that indicates the configuration includes receiving signaling that indicates a reception DRS window. The reception DRS window may include the two or more SSB reception occasions. Additionally, receiving the signaling at the UE 115-e that indicates the configuration may also include receiving signaling that indicates a transmission DRS window. The transmission DRS window may include the two or more SSB transmission occasions. In some cases, resources of the reception DRS window and the resources of the transmission DRS window may be non-overlapping in a time domain. In some other cases, the resources of the reception DRS window and the resources of the transmissionDRS window may be at least partially overlapping in the time domain. Tn such cases, at least at least one of the SSB reception occasions may be positioned between at least two of the SSB transmission occasions in the time domain (e.g., in an interleaved pattern). In some cases, the resources of the reception DRS window and the resources of the transmission DRS window may be non-overlapping in a frequency domain (e.g., positioned in different frequency resources, which may be orthogonal.

[0122] In some other examples, the UE 115-e receiving the signaling that indicates the configuration includes receiving signaling that indicates a DRS window (e.g., a single DRS window). For example, the DRS window may include the two or more SSB reception occasions and the two or more SSB transmissions occasions. In some cases, at least one of the SSB reception occasions may be positioned between at least two of the SSB transmission occasions in the time domain (e.g., in an interleaved pattern).

[0123] In some implementations, the UE 115-e receiving the signaling that indicates the configuration includes receiving an indication of a first quantity of the two or more SSB transmission occasions. Additionally, the configuration may include a second quantity of the two or more SSB reception occasions, or both the first quantity and the second quantity.

[0124] In some examples, the UE 115-e receiving the signaling that indicates the configuration includes receiving an indication of a separation within the time domain between a first SSB occasion and a second SSB occasion of the one or more DRS windows. For example, the indication of the separation between the first SSB occasion and the second SSB occasion may indicate a quantity of slots. In some examples, the indicated quantity of slots may be zero such that the first and second SSB occasions are adjacent to one another. In some cases, each of the two or more SSB reception occasion and each of the two or more transmission occasions may correspond to a respective slot of the one or more DRS windows.

[0125] At 510, the UE 115-e may monitor, based at least in part of the configuration, for a reception of a S-SSB message from the UE 115-d during the two or more SSB reception occasions of the one or more DRS windows.

[0126] At 515, the UE 115-e may receive the first S-SSB message from the UE 115-d during the two or more SSB reception occasions of the one or more DRSwindows. Tn some examples, the UE 1 15-e may receive, from the UE 115-d, the first S- SSB message based at least on the monitoring at 510. In some cases, the first S-SSB message may include synchronization or timing information from the UE 115-d. In such cases, the UE 115-e may not be in the coverage area of the network entity 105-b and the UE 115-d may be in the coverage area of the network entity 105-b. In such examples, the UE 115-d may transmit the first S-SSB message to the UE 115-e. The first S-SSB message may include synchronization or timing information from the network entity 105-b.

[0127] At 520, in some implementations, the UE 115-e may determine a synchronization accuracy of the UE 115-e satisfies a synchronization accuracy threshold. The synchronization accuracy may include a timing or frequency accuracy for the wireless system. The wireless system may be an example of the wireless communication system 100 or the wireless communications system 200.

[0128] At 525, in some cases, the UE 115-e may perform a EBT procedure during the one or more DRS windows. For example, the UE 115-e may transmit the second S- SSB message in response to clearing the LBT procedure. In some examples, the one or more DRS windows may contain two or more SSB transmission occasions in case of EBT procedure failures.

[0129] At 530, the UE 115-e may transmit, based at least on the configuration, the second S-SSB message to the UE 115-f. The UE 115-e may transmit the second S-SSB message to the UE 115-f during at least one SSB transmission occasion of the two or more SSB transmission occasions of the one or more DRS windows. In some examples, the UE 115-e may transmit the second S-SSB message to the UE 115-f during at least one SSB transmission occasion in response to receiving the first S-SSB message from the UE 115-d during at least one of the two or more SSB reception occasions. In some examples, the UE 115-e may transmit the second S-SSB message in response to determining that the synchronization accuracy of the UE 115-e satisfies the synchronization accuracy threshold and / or in response to clearing the LBT procedure.

[0130] FIG. 6 illustrates an example of a process flow 600 that supports discovery reference window configuration for sidelink in accordance with various aspects of the present disclosure. The process flow 600 may implement aspects of wirelesscommunications systems 100 and 200 or may be implemented by aspects of the wireless communications sy stems 100 and 200. For example, the process flow 600 may illustrate operations between a UE 115-g, UE 115-h, UE 115-i and a network entity 105-c, which may be examples of corresponding devices described herein. In the following description of the process flow 600, the operations between the UE 115-g, UE 115-h, UE 115-i and the network entity 105-c may be transmitted in a different order than the example order shown, or the operations performed may be performed in different orders or at different times. Some operations may also be omitted from the process flow 600, and other operations may be added to the process flow 600.

[0131] At 605 -a, the network entity 105-c may transmit a signaling that indicates a configuration for one or more DRS windows to the UE 115-g. The configuration of each of the of the one or more DRS windows may include a first SSB occasion for transmission of a first S-SSB message and a second SSB occasion for transmission of a second S-SSB message. Additionally, the configuration of the one or more DRS widows may include a set of additional SSB transmission occasions

[0132] At 605 -b, the UE 115-g may transmit the signaling that indicates the configuration for the one or more DRS windows to the UE 115-h. The configuration of each the of the one or more DRS windows may include the first SSB occasion for transmission of the first S-SSB message and the second SSB occasion for transmission of the second S-SSB message. Additionally, the configuration of the one or more DRS widows may include the set of additional SSB transmission occasions.

[0133] Further, at 605-b, the UE 115-h may receive the signaling that indicates the configuration for one or more DRS windows from the UE 115-g. In some examples, the UE 115-h may relay the configuration of the one or more DRS windows to the UE 115-i The configuration of each the of the one or more DRS windows may include the first SSB occasion for transmission of the first S-SSB message and the second SSB occasion for transmission of the second S-SSB message. The first SSB occasion may be used by the UE 115-g for transmission of the first S-SSB and used by the UE 115-h for monitoring for transmission of the first S-SSB message by the UE 115-g. The second SSB occasion may be used by the UE 115-h for transmission of the second S-SSB message and used by the UE 115-i for monitoring for transmission by the second S-SSB message by the UE 115-h. In some cases, the UE 115-h may be considered a first UEand the UE 1 15-g may be considered a second UE. Additionally, the configuration of the one or more DRS widows may include the set of additional SSB transmission occasions. The set of additional SSB transmission occasions may be configured for use for S-SSB transmission by any UE 115 of a set of UEs 115. The set of UEs 115 may include the UE 115-g and the UE 115-h. In some examples, each of the first SSB occasion, the second SSB occasion, and the additional SSB transmission occasions may correspond to a respective slot of the one or more DRS windows.

[0134] At 610, the UE 115-h may monitor, based at least on the configuration of the one or more DRS windows received at 605-b, for transmission of the first S-SSB message from the UE 115-g during the first SSB occasion of the one or more DRS windows.

[0135] At 615, the UE 115-h may receive the first S-SSB message from the UE 115-g during the first SSB occasion of the one or more DRS windows.

[0136] At 620, the UE 115-h may attempt to transmit the second S-SSB during the second SSB occasion of the one or more DRS windows. In some examples, whether the second S-SSB message is transmitted during the SSB occasion is based on whether the first S-SSB message is received during the first SSB occasion, whether the synchronization accuracy of the UE 115-h is above a synchronization accuracy threshold, and / or whether the UE 115-h successfully performs an LBT procedure during the second SSB occasion.

[0137] At 625, in some examples, the UE 1 15-h may monitor for transmission of the first S-SSB message from the UE 115-g during a SSB occasion of the set of additional SSB transmission occasions. The UE 115-h may monitor for transmission of the first S-SSB message from the UE 115-g during the SSB occasion of the set of additional SSB transmission occasions based at least on failing to receive or decode the first message during the first SSB occasion (e.g., determining an absence of the first S- SSB message). For example, an LBT procedure performed by the UE 115-g may fail during the first SSB occasion, and as such, the UE 115-g may refrain from transmitting the S-SSB during the first SSB occasion. Further, the UE 115-h may monitor for the first S-SSB message during the set of additional SSB transmission occasions because the synchronization accuracy threshold was determined to not be satisfied.

[0138] At 630, the UE 1 15-h may receive the first S-SSB message during a first additional SSB transmission occasion of the set of additional SSB transmission occasions based on the UE 115-g transmitting the first S-SSB message during the first additional SSB transmission occasion of the set of additional SSB transmission occasions.

[0139] At 640, the UE 115-a may transmit the second S-SSB message during the set of additional SSB transmission occasions. Whether the UE 115-h transmits the second S-SSB message during the set of additional SSB transmission occasions may be based at least on whether the second S-SSB message is transmitted by the UE 115-h during the second SSB occasion. In some cases, the UE 115-h may not transmit the second S- SSB message during the second SSB occasion because the LBT procedure by UE 115-h failed. In some other cases, the UE 115-h may transmit the second S-SSB message to the UE 115-i during a second additional SSB transmission occasion of the set of additional SSB transmission occasions based at least on receiving the first S-SSB message during the first additional SSB transmission occasion. Additionally, the UE 115-h may transmit the second S-SSB message during the SSB transmission occasion of the set of additional transmission occasions based on success of an LBT procedure performed during the SSB transmission occasion of the set of additional transmission occasion.

[0140] FIG. 7 shows a block diagram 700 of a device 705 that supports discovery reference signal window configuration for sidelink in accordance with one or more aspects of the present disclosure. The device 705 may be an example of aspects of a UE 115 as described herein. The device 705 may include a receiver 710, a transmitter 715, and a communications manager 720. The device 705 may also include a processor. Each of these components may be in communication with one another (e g., via one or more buses).

[0141] The receiver 710 may provide a means for receiving information such as packets, user data, control information, or any combination thereof associated with various information channels (e.g., control channels, data channels, information channels related to discovery reference signal window configuration for sidelink). Information may be passed on to other components of the device 705. The receiver 710 may utilize a single antenna or a set of multiple antennas.

[0142] The transmiter 715 may provide a means for transmitting signals generated by other components of the device 705. For example, the transmitter 715 may transmit information such as packets, user data, control information, or any combination thereof associated with various information channels (e.g., control channels, data channels, information channels related to discovery reference signal window configuration for sidelink). In some examples, the transmiter 715 may be co-located with a receiver 710 in a transceiver module. The transmiter 715 may utilize a single antenna or a set of multiple antennas.

[0143] The communications manager 720, the receiver 710, the transmiter 715, or various combinations thereof or various components thereof may be examples of means for performing various aspects of discovery reference signal window configuration for sidelink as described herein. For example, the communications manager 720, the receiver 710, the transmiter 715, or various combinations or components thereof may support a method for performing one or more of the functions described herein.

[0144] In some examples, the communications manager 720, the receiver 710, the transmiter 715, or various combinations or components thereof may be implemented in hardware (e.g., in communications management circuitry). The hardware may include a processor, a digital signal processor (DSP), a central processing unit (CPU), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA) or other programmable logic device, a microcontroller, discrete gate or transistor logic, discrete hardware components, or any combination thereof configured as or otherwise supporting a means for performing the functions described in the present disclosure. In some examples, a processor and memory coupled with the processor may be configured to perform one or more of the functions described herein (e.g., by executing, by the processor, instructions stored in the memory).

[0145] Additionally, or alternatively, in some examples, the communications manager 720, the receiver 710, the transmiter 715, or various combinations or components thereof may be implemented in code (e.g., as communications management software or firmware) executed by a processor. If implemented in code executed by a processor, the functions of the communications manager 720, the receiver 710, the transmiter 715, or various combinations or components thereof may be performed by a general-purpose processor, a DSP, a CPU, an ASIC, an FPGA, a microcontroller, or anycombination of these or other programmable logic devices (e g., configured as or otherwise supporting a means for performing the functions described in the present disclosure).

[0146] In some examples, the communications manager 720 may be configured to perform various operations (e.g., receiving, obtaining, monitoring, outputting, transmitting) using or otherwise in cooperation with the receiver 710, the transmitter 715, or both. For example, the communications manager 720 may receive information from the receiver 710, send information to the transmitter 715, or be integrated in combination with the receiver 710, the transmitter 715, or both to obtain information, output information, or perform various other operations as described herein.

[0147] Additionally, or alternatively, the communications manager 720 may support wireless communication at a first UE in accordance with examples as disclosed herein. For example, the communications manager 720 may be configured as or otherwise support a means for receiving signaling that indicates a configuration for one or more discovery reference signal windows, the one or more discovery reference signal windows including two or more synchronization signal block reception occasions and two or more synchronization signal block transmission occasions in accordance with the configuration. The communications manager 720 may be configured as or otherwise support a means for monitoring, based on the configuration, for a reception of a first sidelink synchronization signal block message from a second UE during the two or more synchronization signal block reception occasions of the one or more discovery reference signal windows. The communications manager 720 may be configured as or otherwise support a means for transmitting, based on the configuration, a second sidelink synchronization signal block message to a third UE during at least one synchronization signal block transmission occasion of the two or more synchronization signal block transmission occasions of the one or more discovery reference signal windows.

[0148] Additionally, or alternatively, the communications manager 720 may support wireless communication at a first UE in accordance with examples as disclosed herein. For example, the communications manager 720 may be configured as or otherwise support a means for receiving signaling that indicates a configuration for one or more discovery reference signal windows that each include a first synchronization signalblock occasion for transmission of a first sidelink synchronization signal block message by a second UE, a second synchronization signal block occasion for transmission of a second sidelink synchronization signal block message by the first UE, and a set of additional synchronization signal block transmission occasions configured for use by any UE of a set of UEs including the first UE and the second UE. The communications manager 720 may be configured as or otherwise support a means for monitoring, based on the configuration, for transmission of the first sidelink synchronization signal block message by the second UE during the first synchronization signal block occasion of the one or more discovery reference signal windows. The communications manager 720 may be configured as or otherwise support a means for attempting, based on the configuration, to transmit the second sidelink synchronization signal block message during the second synchronization signal block occasion of the one or more discovery reference signal windows. In some examples, to, the communications manager 720 may be configured as or otherwise support a means for the first UE monitoring for transmission of the first sidelink synchronization signal block message by the second UE during the set of additional synchronization signal block transmission occasions based on whether the first sidelink synchronization signal block message is received by the first UE during the first synchronization signal block occasion and the first UE transmitting the second sidelink synchronization signal block message during the set of additional synchronization signal block transmission occasions based on whether the second sidelink synchronization signal block message is transmitted by the first UE during the second synchronization signal block occasion.

[0149] By including or configuring the communications manager 720 in accordance with examples as described herein, the device 705 (e.g., a processor controlling or otherwise coupled with the receiver 710, the transmitter 715, the communications manager 720, or a combination thereof) may support techniques for reducing processing due to improved synchronization with a network. For example, by performing the S- SSB procedures according to the DRS window configurations described herein, various UEs may be more efficiently informed of synchronization information, thereby resulting reduced processing overhead due to lack of or reduced synchronization with a network.

[0150] FIG. 8 shows a block diagram 800 of a device 805 that supports discovery reference signal window configuration for sidelink in accordance with one or moreaspects of the present disclosure. The device 805 may be an example of aspects of a device 705 or a UE 115 as described herein. The device 805 may include a receiver 810, a transmitter 815, and a communications manager 820. The device 805 may also include a processor. Each of these components may be in communication with one another (e.g., via one or more buses).

[0151] The receiver 810 may provide a means for receiving information such as packets, user data, control information, or any combination thereof associated with various information channels (e.g., control channels, data channels, information channels related to discovery reference signal window configuration for sidelink). Information may be passed on to other components of the device 805. The receiver 810 may utilize a single antenna or a set of multiple antennas.

[0152] The transmitter 815 may provide a means for transmitting signals generated by other components of the device 805. For example, the transmitter 815 may transmit information such as packets, user data, control information, or any combination thereof associated with various information channels (e.g., control channels, data channels, information channels related to discovery reference signal window configuration for sidelink). In some examples, the transmitter 815 may be co-located with a receiver 810 in a transceiver module. The transmitter 815 may utilize a single antenna or a set of multiple antennas.

[0153] The device 805, or various components thereof, may be an example of means for performing various aspects of discovery reference signal window configuration for sidelink as described herein. For example, the communications manager 820 may include a configuration signaling interface 825, an SSB monitoring component 830, an SSB transmission component 835, or any combination thereof. The communications manager 820 may be an example of aspects of a communications manager 720 as described herein. In some examples, the communications manager 820, or various components thereof, may be configured to perform various operations (e.g., receiving, obtaining, monitoring, outputting, transmitting) using or otherwise in cooperation with the receiver 810, the transmitter 815, or both. For example, the communications manager 820 may receive information from the receiver 810, send information to the transmitter 815, or be integrated in combination with the receiver810, the transmitter 815, or both to obtain information, output information, or perform various other operations as described herein.

[0154] The communications manager 820 may support wireless communication at a first UE in accordance with examples as disclosed herein. The configuration signaling interface 825 may be configured as or otherwise support a means for receiving signaling that indicates a configuration for one or more discovery reference signal windows, the one or more discovery reference signal windows including two or more synchronization signal block reception occasions and two or more synchronization signal block transmission occasions in accordance with the configuration. The SSB monitoring component 830 may be configured as or otherwise support a means for monitoring, based on the configuration, for a reception of a first sidelink synchronization signal block message from a second UE during the two or more synchronization signal block reception occasions of the one or more discovery reference signal windows. The SSB transmission component 835 may be configured as or otherwise support a means for transmitting, based on the configuration, a second sidelink synchronization signal block message to a third UE during at least one synchronization signal block transmission occasion of the two or more synchronization signal block transmission occasions of the one or more discovery reference signal windows.

[0155] Additionally, or alternatively, the communications manager 820 may support wireless communication at a first UE in accordance with examples as disclosed herein. The configuration signaling interface 825 may be configured as or otherwise support a means for receiving signaling that indicates a configuration for one or more discovery reference signal windows that each include a first synchronization signal block occasion for transmission of a first sidelink synchronization signal block message by a second UE, a second synchronization signal block occasion for transmission of a second sidelink synchronization signal block message by the first UE, and a set of additional synchronization signal block transmission occasions configured for use by any UE of a set of UEs including the first UE and the second UE. The SSB monitoring component 830 may be configured as or otherwise support a means for monitoring, based on the configuration, for transmission of the first sidelink synchronization signal block message by the second UE during the first synchronization signal block occasion of the one or more discovery reference signal windows. The SSB transmission component 835may be configured as or otherwise support a means for attempting, based on the configuration, to transmit the second sidelink synchronization signal block message during the second synchronization signal block occasion of the one or more discovery reference signal windows. In some examples, to, the SSB receiving component 840 may be configured as or otherwise support a means for the first UE monitoring for transmission of the first sidelink synchronization signal block message by the second UE during the set of additional synchronization signal block transmission occasions based on whether the first sidelink synchronization signal block message is received by the first UE during the first synchronization signal block occasion, and the additional occasion component 845 may be configured as or otherwise support a means for the first UE transmitting the second sidelink synchronization signal block message during the set of additional synchronization signal block transmission occasions based on whether the second sidelink synchronization signal block message is transmitted by the first UE during the second synchronization signal block occasion.

[0156] FIG. 9 shows a block diagram 900 of a communications manager 920 that supports discovery reference signal window configuration for sidelink in accordance with one or more aspects of the present disclosure. The communications manager 920 may be an example of aspects of a communications manager 720, a communications manager 820, or both, as described herein. The communications manager 920, or various components thereof, may be an example of means for performing various aspects of discovery reference signal window configuration for sidelink as described herein. For example, the communications manager 920 may include a configuration signaling interface 925, an SSB monitoring component 930, an SSB transmission component 935, an SSB occasion configuration interface 940, an additional occasion component 945, an SSB absence component 950, a synchronization accuracy component 955, an SSB receiving component 960, an LBT component 965 or any combination thereof. Each of these components may communicate, directly or indirectly, with one another (e g., via one or more buses).

[0157] Additionally, or alternatively, the communications manager 920 may support wireless communication at a first UE in accordance with examples as disclosed herein. The configuration signaling interface 925 may be configured as or otherwise support a means for receiving signaling that indicates a configuration for one or more discoveryreference signal windows, the one or more discovery reference signal windows including two or more synchronization signal block reception occasions and two or more synchronization signal block transmission occasions in accordance with the configuration. The SSB monitoring component 930 may be configured as or otherwise support a means for monitoring, based on the configuration, for a reception of a first sidelink synchronization signal block message from a second UE during the two or more synchronization signal block reception occasions of the one or more discovery reference signal windows. The SSB transmission component 935 may be configured as or otherwise support a means for transmitting, based on the configuration, a second sidelink synchronization signal block message to a third UE during at least one synchronization signal block transmission occasion of the two or more synchronization signal block transmission occasions of the one or more discovery reference signal windows.

[0158] In some examples, to support receiving the signaling that indicates the configuration, the configuration signaling interface 925 may be configured as or otherwise support a means for receiving signaling that indicates a reception discovery reference signal window that includes the two or more synchronization signal block reception occasions and a transmission discovery reference signal window that includes the two or more synchronization signal block transmission occasions.

[0159] In some examples, to support receiving the signaling that indicates the configuration, the configuration signaling interface 925 may be configured as or otherwise support a means for receiving signaling that indicates a discovery reference signal window that includes the two or more synchronization signal block reception occasions and the two or more synchronization signal block transmission occasions.

[0160] In some examples, to support receiving the signaling that indicates the configuration, the SSB occasion configuration interface 940 may be configured as or otherwise support a means for receiving an indication of a first quantity of the two or more synchronization signal block transmission occasions, a second quantity of the two or more synchronization signal block reception occasions, or both the first quantity and the second quantity.

[0161] Additionally, or alternatively, the communications manager 920 may support wireless communication at a first UE in accordance with examples as disclosed herein. In some examples, the configuration signaling interface 925 may be configured as or otherwise support a means for receiving signaling that indicates a configuration for one or more discovery reference signal windows that each include a first synchronization signal block occasion for transmission of a first sidelink synchronization signal block message by a second UE, a second synchronization signal block occasion for transmission of a second sidelink synchronization signal block message by the first UE, and a set of additional synchronization signal block transmission occasions configured for use by any UE of a set of UEs including the first UE and the second UE. In some examples, the SSB monitoring component 930 may be configured as or otherwise support a means for monitoring, based on the configuration, for transmission of the first sidelink synchronization signal block message by the second UE during the first synchronization signal block occasion of the one or more discovery reference signal windows. In some examples, the SSB transmission component 935 may be configured as or otherwise support a means for attempting, based on the configuration, to transmit the second sidelink synchronization signal block message during the second synchronization signal block occasion of the one or more discovery reference signal windows. In some examples, the SSB receiving component 960 may be configured as or otherwise support a means for the first UE monitoring for transmission of the first sidelink synchronization signal block message by the second UE during the set of additional synchronization signal block transmission occasions based on whether the first sidelink synchronization signal block message is received by the first UE during the first synchronization signal block occasion, and the additional occasion component 945 may be configured as or otherwise support a means for the first UE transmitting the second sidelink synchronization signal block message during the set of additional synchronization signal block transmission occasions based on whether the second sidelink synchronization signal block message is transmitted by the first UE during the second synchronization signal block occasion.

[0162] In some examples, the additional occasion component 945 may be configured as or otherwise support a means for transmitting the second sidelink synchronization signal block message during a synchronization signal blocktransmission occasion of the set of additional synchronization signal block transmission occasions based on a failure of the listen-before-talk procedure during the second synchronization signal block occasion.

[0163] In some examples, the SSB absence component 950 may be configured as or otherwise support a means for determining an absence of the first sidelink synchronization signal block message from the first synchronization signal block occasion based on the monitoring during the first synchronization signal block occasion. In some examples, the SSB monitoring component 930 may be configured as or otherwise support a means for monitoring for transmission of the first sidelink synchronization signal block message by the second UE during a synchronization signal block transmission occasion of the set of additional synchronization signal block transmission occasions based on the absence of the first sidelink synchronization signal block message from the first synchronization signal block occasion.

[0164] In some examples, the synchronization accuracy component 955 may be configured as or otherwise support a means for determining that a synchronization accuracy of the first UE does is lower than a synchronization accuracy threshold. In some examples, the SSB monitoring component 930 may be configured as or otherwise support a means for monitoring for transmission of the first sidelink synchronization signal block message by the second UE during a synchronization signal block transmission occasion of the set of additional synchronization signal block transmission occasions based on determining that the synchronization accuracy of the first UE is lower than the synchronization accuracy threshold.

[0165] In some examples, the synchronization accuracy component 955 may be configured as or otherwise support a means for determining that a synchronization accuracy of the first UE satisfies a synchronization accuracy threshold, wherein the first UE transmits the second sidelink synchronization signal block message in response to determining that the synchronization accuracy of the first UE satisfies the synchronization accuracy threshold.

[0166] In some examples, the SSB receiving component 960 may be configured as or otherwise support a means for the first UE receiving, from the second UE based at on the monitoring, the first sidelink synchronization signal block message, wherein the firstUE transmits the second sidelink synchronization signal block message during at least one synchronization signal block transmission occasion in response to receiving the first sidelink synchronization signal block message during at least one of the two or more synchronization signal block reception occasions.

[0167] In some examples, the SSB receiving component 960 may be configured as or otherwise support a means for the first UE receiving the first sidelink synchronization signal block message during a first additional synchronization signal block transmission occasion of the set of additional synchronization signal block transmission occasions. In some examples, the SSB transmission component 935 may be configured as or otherwise support a means for transmitting the second sidelink synchronization signal block message during a second additional synchronization signal block transmission occasion of the set of additional synchronization signal block transmission occasions based at least in part on receiving the first sidelink synchronization signal block message during the first additional synchronization signal block transmission occasion.

[0168] In some examples, the LBT component 965 may be configured as or otherwise support a means for performing a listen-before-talk procedure during the one or more discovery reference signal windows, where the first UE transmits the second sidelink synchronization signal block message in response to clearing the listen-before- talk procedure.

[0169] FIG. 10 shows a diagram of a system 1000 including a device 1005 that supports discovery reference signal window configuration for sidelink in accordance with one or more aspects of the present disclosure. The device 1005 may be an example of or include the components of a device 705, a device 805, or a UE 115 as described herein. The device 1005 may communicate (e.g., wirelessly) with one or more network entities 105, one or more UEs 115, or any combination thereof. The device 1005 may include components for bi-directional voice and data communications including components for transmitting and receiving communications, such as a communications manager 1020, an input / output (I / O) controller 1010, a transceiver 1015, an antenna 1025, a memory 1030, code 1035, and a processor 1040. These components may be in electronic communication or otherwise coupled (e.g., operatively, communicatively, functionally, electronically, electrically) via one or more buses (e.g., a bus 1045).

[0170] The I / O controller 1010 may manage input and output signals for the device 1005. The I / O controller 1010 may also manage peripherals not integrated into the device 1005. In some cases, the I / O controller 1010 may represent a physical connection or port to an external peripheral. In some cases, the I / O controller 1010 may utilize an operating system such as iOS®, ANDROID®, MS-DOS®, MS-WINDOWS®, OS / 2®, UNIX®, LINUX®, or another known operating system. Additionally, or alternatively, the I / O controller 1010 may represent or interact with a modem, a keyboard, a mouse, a touchscreen, or a similar device. In some cases, the I / O controller 1010 may be implemented as part of a processor, such as the processor 1040. In some cases, a user may interact with the device 1005 via the I / O controller 1010 or via hardware components controlled by the I / O controller 1010.

[0171] In some cases, the device 1005 may include a single antenna 1025. However, in some other cases, the device 1005 may have more than one antenna 1025, which may be capable of concurrently transmitting or receiving multiple wireless transmissions. The transceiver 1015 may communicate bi-directionally, via the one or more antennas 1025, wired, or wireless links as described herein. For example, the transceiver 1015 may represent a wireless transceiver and may communicate bi-directionally with another wireless transceiver. The transceiver 1015 may also include a modem to modulate the packets, to provide the modulated packets to one or more antennas 1025 for transmission, and to demodulate packets received from the one or more antennas 1025. The transceiver 1015, or the transceiver 1015 and one or more antennas 1025, may be an example of a transmitter 715, a transmitter 815, a receiver 710, a receiver 810, or any combination thereof or component thereof, as described herein.

[0172] The memory 1030 may include random access memory (RAM) and readonly memory (ROM). The memory 1030 may store computer-readable, computerexecutable code 1035 including instructions that, when executed by the processor 1040, cause the device 1005 to perform various functions described herein. The code 1035 may be stored in a non-transitory computer-readable medium such as system memory or another type of memory. In some cases, the code 1035 may not be directly executable by the processor 1040 but may cause a computer (e.g., when compiled and executed) to perform functions described herein. In some cases, the memory 1030 may contain,among other things, a basic I / O system (BIOS) which may control basic hardware or software operation such as the interaction with peripheral components or devices.

[0173] The processor 1040 may include an intelligent hardware device (e.g., a general-purpose processor, a DSP, a CPU, a microcontroller, an ASIC, an FPGA, a programmable logic device, a discrete gate or transistor logic component, a discrete hardware component, or any combination thereof). In some cases, the processor 1040 may be configured to operate a memory array using a memory controller. In some other cases, a memory controller may be integrated into the processor 1040. The processor 1040 may be configured to execute computer-readable instructions stored in a memory (e.g., the memory 1030) to cause the device 1005 to perform various functions (e.g., functions or tasks supporting discovery reference signal window configuration for sidelink). For example, the device 1005 or a component of the device 1005 may include a processor 1040 and memory 1030 coupled with or to the processor 1040, the processor 1040 and memory 1030 configured to perform various functions described herein.

[0174] Additionally, or alternatively, the communications manager 1020 may support wireless communication at a first UE in accordance with examples as disclosed herein. For example, the communications manager 1020 may be configured as or otherwise support a means for receiving signaling that indicates a configuration for one or more discovery reference signal windows, the one or more discovery reference signal windows including two or more synchronization signal block reception occasions and two or more synchronization signal block transmission occasions in accordance with the configuration. The communications manager 1020 may be configured as or otherwise support a means for monitoring, based on the configuration, for a reception of a first sidelink synchronization signal block message from a second UE during the two or more synchronization signal block reception occasions of the one or more discovery reference signal windows. The communications manager 1020 may be configured as or otherwise support a means for transmitting, based on the configuration, a second sidelink synchronization signal block message to a third UE during at least one synchronization signal block transmission occasion of the two or more synchronization signal block transmission occasions of the one or more discovery reference signal windows.

[0175] Additionally, or alternatively, the communications manager 1020 may support wireless communication at a first UE in accordance with examples as disclosed herein. For example, the communications manager 1020 may be configured as or otherwise support a means for receiving signaling that indicates a configuration for one or more discovery reference signal windows that each include a first synchronization signal block occasion for transmission of a first sidelink synchronization signal block message by a second UE, a second synchronization signal block occasion for transmission of a second sidelink synchronization signal block message by the first UE, and a set of additional synchronization signal block transmission occasions configured for use by any UE of a set of UEs including the first UE and the second UE. The communications manager 1020 may be configured as or otherwise support a means for monitoring, based on the configuration, for transmission of the first sidelink synchronization signal block message by the second UE during the first synchronization signal block occasion of the one or more discovery reference signal windows. The communications manager 1020 may be configured as or otherwise support a means for attempting, based on the configuration, to transmit the second sidelink synchronization signal block message during the second synchronization signal block occasion of the one or more discovery reference signal windows. In some examples, to attempt to transmit the sidelink sy nchronization signal block message, the communications manager 1020 may be configured as or otherwise support a means for the first UE monitoring for transmission of the first sidelink synchronization signal block message by the second UE during the set of additional synchronization signal block transmission occasions based on whether the first sidelink synchronization signal block message is received by the first UE during the first synchronization signal block occasion and the first UE transmitting the second sidelink synchronization signal block message during the set of additional synchronization signal block transmission occasions based on whether the second sidelink synchronization signal block message is transmitted by the first UE during the second synchronization signal block occasion.

[0176] By including or configuring the communications manager 1020 in accordance with examples as described herein, the device 1005 may support techniques for improved communication reliability due to improved synchronization with a network. For example, by performing the S-SSB procedures according to the DRSwindow configurations described herein, various UEs may be more efficiently informed of synchronization information, thereby resulting improved communication reliably by improving synchronization.

[0177] In some examples, the communications manager 1020 may be configured to perform various operations (e.g., receiving, monitoring, transmitting) using or otherwise in cooperation with the transceiver 1015, the one or more antennas 1025, or any combination thereof. Although the communications manager 1020 is illustrated as a separate component, in some examples, one or more functions described with reference to the communications manager 1020 may be supported by or performed by the processor 1040, the memory 1030, the code 1035, or any combination thereof. For example, the code 1035 may include instructions executable by the processor 1040 to cause the device 1005 to perform various aspects of discovery reference signal window configuration for sidelink as described herein, or the processor 1040 and the memory 1030 may be otherwise configured to perform or support such operations.

[0178] FIG. 11 shows a flowchart illustrating a method 1100 that supports discovery reference signal window configuration for sidelink in accordance with one or more aspects of the present disclosure. The operations of the method 1100 may be implemented by a UE or its components as described herein. For example, the operations of the method 1100 may be performed by a UE 115 as descnbed with reference to FIGs. 1 through 10. In some examples, a UE may execute a set of instructions to control the functional elements of the UE to perform the described functions. Additionally, or alternatively, the UE may perform aspects of the described functions using special-purpose hardware.

[0179] At 1105, the method may include receiving signaling that indicates a configuration for one or more discovery reference signal windows, the one or more discovery reference signal windows including two or more synchronization signal block reception occasions and two or more synchronization signal block transmission occasions in accordance with the configuration. The operations of 1105 may be performed in accordance with examples as disclosed herein. In some examples, aspects of the operations of 1105 may be performed by a configuration signaling interface 925 as described with reference to FIG. 9.

[0180] At 1 110, the method may include monitoring, based on the configuration, for a reception of a first sidelink synchronization signal block message from a second UE during the two or more synchronization signal block reception occasions of the one or more discovery reference signal windows. The operations of 1110 may be performed in accordance with examples as disclosed herein. In some examples, aspects of the operations of 1110 may be performed by an SSB monitoring component 930 as described with reference to FIG. 9.

[0181] At 1115, the method may include transmitting, based on the configuration, a second sidelink synchronization signal block message to a third UE during at least one synchronization signal block transmission occasion of the two or more synchronization signal block transmission occasions of the one or more discovery reference signal windows. The operations of 1115 may be performed in accordance with examples as disclosed herein. In some examples, aspects of the operations of 1115 may be performed by an SSB transmission component 935 as descnbed with reference to FIG 9

[0182] FIG. 12 shows a flowchart illustrating a method 1200 that supports discovery reference signal window configuration for sidelink in accordance with one or more aspects of the present disclosure. The operations of the method 1200 may be implemented by a UE or its components as described herein. For example, the operations of the method 1200 may be performed by a UE 115 as described with reference to FIGs. 1 through 10. In some examples, a UE may execute a set of instructions to control the functional elements of the UE to perform the described functions. Additionally, or alternatively, the UE may perform aspects of the described functions using special-purpose hardware.

[0183] At 1205, the method may include receiving signaling that indicates a configuration for a reception discovery reference signal window that comprises two or more synchronization signal block reception occasions and a transmission discovery reference signal window that comprises two or more synchronization signal block transmission occasions. The operations of 1205 may be performed in accordance with examples as disclosed herein. In some examples, aspects of the operations of 1205 may be performed by a configuration signaling interface 925 as described with reference to FIG. 9.

[0184] At 1210, the method may include monitoring, based on the configuration, for a reception of a first sidelink synchronization signal block message from a second UE during the two or more synchronization signal block reception occasions of the reception discovery reference signal window. The operations of 1210 may be performed in accordance with examples as disclosed herein. In some examples, aspects of the operations of 1210 may be performed by an SSB monitoring component 930 as described with reference to FIG. 9.

[0185] At 1215, the method may include transmitting, based on the configuration, a second sidelink synchronization signal block message to a third UE during at least one synchronization signal block transmission occasion of the two or more synchronization signal block transmission occasions of the transmission discovery reference signal window. The operations of 1215 may be performed in accordance with examples as disclosed herein. In some examples, aspects of the operations of 1215 may be performed by an SSB transmission component 935 as descnbed with reference to FIG 9

[0186] FIG. 13 shows a flowchart illustrating a method 1300 that supports discovery reference signal window configuration for sidelink in accordance with one or more aspects of the present disclosure. The operations of the method 1300 may be implemented by a UE or its components as described herein. For example, the operations of the method 1300 may be performed by a UE 115 as described with reference to FIGs. 1 through 10. In some examples, a UE may execute a set of instructions to control the functional elements of the UE to perform the described functions. Additionally, or alternatively, the UE may perform aspects of the described functions using special-purpose hardware.

[0187] At 1305, the method may include receiving signaling that indicates a configuration for a discovery reference signal window that comprises two or more synchronization signal block reception occasions and two or more synchronization signal block transmission occasions. The operations of 1305 may be performed in accordance with examples as disclosed herein. In some examples, aspects of the operations of 1305 may be performed by a configuration signaling interface 925 as described with reference to FIG. 9.

[0188] At 1310, the method may include monitoring, based on the configuration, for a reception of a first sidelink synchronization signal block message from a second UE during the two or more synchronization signal block reception occasions of the discovery reference signal window. The operations of 1310 may be performed in accordance with examples as disclosed herein. In some examples, aspects of the operations of 1310 may be performed by an SSB monitoring component 930 as described with reference to FIG. 9.

[0189] At 1315, the method may include transmitting, based on the configuration, a second sidelink synchronization signal block message to a third UE during at least one synchronization signal block transmission occasion of the two or more synchronization signal block transmission occasions of the discovery' reference signal window. The operations of 1315 may be performed in accordance with examples as disclosed herein. In some examples, aspects of the operations of 1315 may be performed by an SSB transmission component 935 as described with reference to FIG. 9.

[0190] FIG. 14 shows a flowchart illustrating a method 1400 that supports discovery reference signal window configuration for sidelink in accordance with one or more aspects of the present disclosure. The operations of the method 1400 may be implemented by a UE or its components as described herein. For example, the operations of the method 1400 may be performed by a UE 115 as descnbed with reference to FIGs. 1 through 10. In some examples, a UE may execute a set of instructions to control the functional elements of the UE to perform the described functions. Additionally, or alternatively, the UE may perform aspects of the described functions using special-purpose hardware.

[0191] At 1405, the method may include receiving signaling that indicates a configuration for one or more discovery reference signal windows that each include a first synchronization signal block occasion for transmission of a first sidelink synchronization signal block message by a second UE, a second synchronization signal block occasion for transmission of a second sidelink synchronization signal block message by the first UE, and a set of additional synchronization signal block transmission occasions configured for use by any UE of a set of UEs including the first UE and the second UE. The operations of 1405 may be performed in accordance with examples as disclosed herein. In some examples, aspects of the operations of 1405 maybe performed by a configuration signaling interface 925 as described with reference to FIG. 9.

[0192] At 1410, the method may include monitoring, based on the configuration, for transmission of the first sidelink synchronization signal block message by the second UE during the first synchronization signal block occasion of the one or more discovery reference signal windows. The operations of 1410 may be performed in accordance with examples as disclosed herein. In some examples, aspects of the operations of 1410 may be performed by an SSB monitoring component 930 as described with reference to FIG. 9.

[0193] At 1415, the method may include attempting, based on the configuration, to transmit the second sidelink synchronization signal block message during the second synchronization signal block occasion of the one or more discovery reference signal windows. The operations of 1415 may be performed in accordance with examples as disclosed herein. In some examples, aspects of the operations of 1415 may be performed by an SSB transmission component 935 as described with reference to FIG. 9.

[0194] In some examples, whether the first UE monitors for transmission of the first sidelink synchronization signal block message by the second UE during the set of additional synchronization signal block transmission occasions is based on whether the first sidelink synchronization signal block message is received by the first UE during the first synchronization signal block occasion. For example, if the first sidelink synchronization signal block message is not received by the first UE during the first synchronization signal block occasion, the method may include, at 1420, monitoring for transmission of the first sidelink synchronization signal block message by the second UE during the set of additional synchronization signal block transmission occasions. If the first sidelink synchronization signal block message is received by the first UE during the first synchronization signal block occasion, then the first UE may not monitor for transmission of the first sidelink synchronization signal block message by the second UE during the set of additional synchronization signal block transmission occasions. The operations of 1420 may be performed in accordance with examples as disclosed herein. In some examples, aspects of the operations of 1420 may be performed by an SSB monitoring component 930 as described with reference to FIG. 9.

[0195] Additionally or alternatively, whether the first UE transmits the second sidelink synchronization signal block message during the set of additional synchronization signal block transmission occasions is based on whether the second sidelink synchronization signal block message is transmitted by the first UE during the second synchronization signal block occasion. For example, if the second sidelink synchronization signal block message is not transmitted during the second synchronization signal block occasion, the method may include, at 1425, transmitting the second sidelink synchronization signal block message during the set of additional synchronization signal block transmission occasions. If the second sidelink synchronization signal block message is transmitted during the second synchronization signal block occasion, then the first UE may not transmit the second sidelink synchronization signal block message during the set of additional synchronization signal block transmission occasions. The operations of 1425 may be performed in accordance with examples as disclosed herein. In some examples, aspects of the operations of 1425 may be performed by an SSB transmission component 935 as described with reference to FIG. 9.

[0196] The following provides an overview of aspects of the present disclosure:

[0197] Aspect 1: A method for wireless communication at a first UE, comprising: receiving signaling that indicates a configuration for one or more discovery reference signal windows, the one or more discovery reference signal windows comprising two or more synchronization signal block reception occasions and two or more synchronization signal block transmission occasions in accordance with the configuration; monitoring, based at least in part on the configuration, for a reception of a first sidelink synchronization signal block message from a second UE during the two or more synchronization signal block reception occasions of the one or more discovery reference signal windows; and transmitting, based at least in part on the configuration, a second sidelink synchronization signal block message to a third UE during at least one synchronization signal block transmission occasion of the two or more synchronization signal block transmission occasions of the one or more discovery reference signal windows.

[0198] Aspect 2: The method of aspect 1, wherein receiving the signaling that indicates the configuration comprises: receiving signaling that indicates a receptiondiscovery reference signal window that comprises the two or more synchronization signal block reception occasions and a transmission discovery reference signal window that includes the two or more synchronization signal block transmission occasions.

[0199] Aspect 3: The method of aspect 2, wherein resources of the reception discovery reference signal window and resources of the transmission discovery reference signal window are non-overlapping in a time domain.

[0200] Aspect 4: The method of any of aspects 2 through 3, wherein resources of the reception discovery reference signal window and resources of the transmission discovery reference signal window are at least partially overlapping in a time domain.

[0201] Aspect 5: The method of aspect 4, wherein at least one of the synchronization signal block reception occasions is positioned between at least two of the synchronization signal block transmission occasions in a time domain.

[0202] Aspect 6: The method of any of aspects 2 through 5, wherein resources of the reception discovery reference signal window and resources of the transmission discovery reference signal window are non-overlapping in a frequency domain.

[0203] Aspect 7: The method of aspect 1, wherein receiving the signaling that indicates the configuration comprises: receiving signaling that indicates a discovery reference signal window that comprises the two or more synchronization signal block reception occasions and the two or more synchronization signal block transmission occasions.

[0204] Aspect 8: The method of aspect 7, wherein at least one of the synchronization signal block reception occasions is positioned between at least two of the synchronization signal block transmission occasions in a time domain.

[0205] Aspect 9: The method of any of aspects 1 through 8, wherein receiving the signaling that indicates the configuration comprises: receiving an indication of a first quantity of the two or more synchronization signal block transmission occasions, a second quantity of the two or more synchronization signal block reception occasions, or both the first quantity and the second quantity.

[0206] Aspect 10: The method of any of aspects 1 through 9, wherein receiving the signaling that indicates the configuration comprises: receiving an indication of aseparation within a time domain between a first synchronization signal block occasion and a second synchronization signal block occasion of the one or more discovery reference signal windows.

[0207] Aspect 11 : The method of aspect 10, wherein the indication of the separation indicates a quantity of slots.

[0208] Aspect 12: The method of aspect 11, wherein the indicated quantity of slots is zero.

[0209] Aspect 13: The method of any of aspects 1 through 12, further comprising: performing a listen-before-talk procedure during the one or more discovery reference signal windows, wherein the first UE transmits the second sidelink synchronization signal block message in response to clearing the listen-before-talk procedure.

[0210] Aspect 14: The method of any of aspects 1 through 13, further comprising: receiving, from the second UE based at least in part on the monitoring, the first sidelink synchronization signal block message, wherein the first UE transmits the second sidelink synchronization signal block message during at least one synchronization signal block transmission occasion in response to receiving the first sidelink synchronization signal block message during at least one of the two or more synchronization signal block reception occasions.

[0211] Aspect 15: The method of any of aspects 1 through 14, further comprising: determining that a synchronization accuracy of the first UE satisfies a synchronization accuracy threshold, wherein the first UE transmits the second sidelink synchronization signal block message in response to determining that the synchronization accuracy of the first UE satisfies the synchronization accuracy threshold.

[0212] Aspect 16: The method of any of aspects 1 through 15, wherein each of the two or more synchronization signal block reception occasions and each of the two or more synchronization signal block transmission occasions corresponds to a respective slot of the one or more discovery' reference signal windows.

[0213] Aspect 17: A method for wireless communication at a first UE, comprising: receiving signaling that indicates a configuration for one or more discovery reference signal windows that each comprise a first synchronization signal block occasion fortransmission of a first sidelink synchronization signal block message by a second UE, a second synchronization signal block occasion for transmission of a second sidelink synchronization signal block message by the first UE, and a set of additional synchronization signal block transmission occasions configured for use by any UE of a set of UEs comprising the first UE and the second UE; monitoring, based at least in part on the configuration, for transmission of the first sidelink synchronization signal block message by the second UE during the first synchronization signal block occasion of the one or more discovery reference signal windows; and attempting, based at least in part on the configuration, to transmit the second sidelink synchronization signal block message during the second synchronization signal block occasion of the one or more discovery reference signal windows, wherein: whether the first UE monitors for transmission of the first sidelink synchronization signal block message by the second UE during the set of additional synchronization signal block transmission occasions is based at least in part on whether the first sidelink synchronization signal block message is received by the first UE during the first synchronization signal block occasion; and whether the first UE transmits the second sidelink synchronization signal block message during the set of additional synchronization signal block transmission occasions is based at least in part on whether the second sidehnk synchronization signal block message is transmitted by the first UE during the second synchronization signal block occasion.

[0214] Aspect 18: The method of aspect 17, wherein attempting to transmit the second sidelink synchronization signal block message during the second synchronization signal block occasion comprises performing a listen-before-talk procedure dunng the second synchronization signal block occasion, the method further comprising: transmitting the second sidelink synchronization signal block message during a synchronization signal block transmission occasion of the set of additional synchronization signal block transmission occasions based at least in part on a failure of the listen-before-talk procedure during the second synchronization signal block occasion.

[0215] Aspect 19: The method of any of aspects 17 through 18, further comprising: determining an absence of the first sidelink synchronization signal block message from the first synchronization signal block occasion based at least in part on the monitoring during the first synchronization signal block occasion; and monitoring for transmissionof the first sidelink synchronization signal block message by the second UE during a synchronization signal block transmission occasion of the set of additional synchronization signal block transmission occasions based at least in part on the absence of the first sidelink synchronization signal block message from the first synchronization signal block occasion.

[0216] Aspect 20: The method of any of aspects 17 through 19, further comprising: determining that a synchronization accuracy of the first UE does is lower than a synchronization accuracy threshold; and monitoring for transmission of the first sidelink synchronization signal block message by the second UE during a synchronization signal block transmission occasion of the set of additional synchronization signal block transmission occasions based at least in part on determining that the synchronization accuracy of the first UE is lower than the synchronization accuracy threshold.

[0217] Aspect 21 : The method of any of aspects 17 through 20, further comprising: receiving the first sidelink synchronization signal block message during a first additional synchronization signal block transmission occasion of the set of additional synchronization signal block transmission occasions; and transmitting the second sidelink synchronization signal block message during a second additional synchronization signal block transmission occasion of the set of additional synchronization signal block transmission occasions based at least in part on receiving the first sidelink synchronization signal block message during the first additional synchronization signal block transmission occasion.

[0218] Aspect 22: The method of any of aspects 17 through 21, wherein each of the first synchronization signal block occasion, the second synchronization signal block occasion, and the additional synchronization signal block transmission occasions corresponds to a respective slot of the one or more discovery reference signal windows.

[0219] Aspect 23: An apparatus for wireless communication at a first UE, comprising a processor; memory coupled with the processor; and instructions stored in the memory and executable by the processor to cause the apparatus to perform a method of any of aspects 1 through 16.

[0220] Aspect 24: An apparatus for wireless communication at a first UE, comprising at least one means for performing a method of any of aspects 1 through 16.

[0221] Aspect 25: A non-transitory computer-readable medium storing code for wireless communication at a first UE, the code comprising instructions executable by a processor to perform a method of any of aspects 1 through 16.

[0222] Aspect 26: An apparatus for wireless communication at a first UE, comprising a processor; memory coupled with the processor; and instructions stored in the memory and executable by the processor to cause the apparatus to perform a method of any of aspects 17 through 22.

[0223] Aspect 27: An apparatus for wireless communication at a first UE, comprising at least one means for performing a method of any of aspects 17 through 22.

[0224] Aspect 28: A non-transitory computer-readable medium storing code for wireless communication at a first UE, the code comprising instructions executable by a processor to perform a method of any of aspects 17 through 22.

[0225] It should be noted that the methods described herein describe possible implementations, and that the operations and the steps may be rearranged or otherwise modified and that other implementations are possible. Further, aspects from two or more of the methods may be combined.

[0226] Although aspects of an LTE, LTE-A, LTE-A Pro, or NR system may be described for purposes of example, and LTE, LTE-A, LTE-A Pro, or NR terminology may be used in much of the description, the techniques described herein are applicable beyond LTE, LTE-A, LTE-A Pro, or NR networks. For example, the described techniques may be applicable to various other wireless communications systems such as Ultra Mobile Broadband (UMB), Institute of Electrical and Electronics Engineers (IEEE) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, Flash-OFDM, as well as other systems and radio technologies not explicitly mentioned herein.

[0227] Information and signals described herein may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout the description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

[0228] The various illustrative blocks and components described in connection with the disclosure herein may be implemented or performed using a general-purpose processor, a DSP, an ASIC, a CPU, an FPGA or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general-purpose processor may be a microprocessor but, in the alternative, the processor may be any processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices (e.g., a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration).

[0229] The functions described herein may be implemented using hardware, software executed by a processor, firmware, or any combination thereof. If implemented using software executed by a processor, the functions may be stored as or transmitted using one or more instructions or code of a computer-readable medium. Other examples and implementations are within the scope of the disclosure and appended claims. For example, due to the nature of software, functions described herein may be implemented using software executed by a processor, hardware, firmware, hardwiring, or combinations of any of these. Features implementing functions may also be physically located at various positions, including being distributed such that portions of functions are implemented at different physical locations.

[0230] Computer-readable media includes both non-transitory computer storage media and communication media including any medium that facilitates transfer of a computer program from one location to another. A non-transitory storage medium may be any available medium that may be accessed by a general-purpose or special-purpose computer. By way of example, and not limitation, non-transitory computer-readable media may include RAM, ROM, electrically erasable programmable ROM (EEPROM), flash memory. compact disk (CD) ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other non-transitory medium that may be used to carry or store desired program code means in the form of instructions or data structures and that may be accessed by a general-purpose or special-purpose computer, or a general-purpose or special-purpose processor. Also, any connection is properly termed a computer-readable medium. For example, if the software is transmitted from awebsite, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of computer-readable medium. Disk and disc, as used herein, include CD, laser disc, optical disc, digital versatile disc (DVD), floppy disk and Blu-ray disc. Disks may reproduce data magnetically, and discs may reproduce data optically using lasers. Combinations of the above are also included within the scope of computer-readable media.

[0231] As used herein, including in the claims, “or” as used in a list of items (e.g., a list of items prefaced by a phrase such as “at least one of’ or “one or more of’) indicates an inclusive list such that, for example, a list of at least one of A, B, or C means A or B or C or AB or AC or BC or ABC (i.e., A and B and C). Also, as used herein, the phrase “based on” shall not be construed as a reference to a closed set of conditions. For example, an example step that is described as “based on condition A” may be based on both a condition A and a condition B without departing from the scope of the present disclosure. In other words, as used herein, the phrase “based on” shall be construed in the same manner as the phrase “based at least in part on.” Also, as used herein, the phrase “a set” shall be construed as including the possibility of a set with one member. That is, the phrase “a set” shall be construed in the same manner as “one or more.”

[0232] The term “determine” or “determining” encompasses a variety of actions and, therefore, “determining” can include calculating, computing, processing, deriving, investigating, looking up (such as via looking up in a table, a database, or another data structure), ascertaining and the like. Also, “determining” can include receiving (e.g., receiving information), accessing (e.g., accessing data stored in memory) and the like. Also, “determining” can include resolving, obtaining, selecting, choosing, establishing, and other such similar actions.

[0233] In the appended figures, similar components or features may have the same reference label. Further, various components of the same type may be distinguished by following the reference label by a dash and a second label that distinguishes among the similar components. If just the first reference label is used in the specification, the description is applicable to any one of the similar components having the same firstreference label irrespective of the second reference label, or other subsequent reference label.

[0234] The description set forth herein, in connection with the appended drawings, describes example configurations and does not represent all the examples that may be implemented or that are within the scope of the claims. The term “example” used herein means “serving as an example, instance, or illustration,” and not “preferred” or “advantageous over other examples.” The detailed description includes specific details for the purpose of providing an understanding of the described techniques. These techniques, however, may be practiced without these specific details. In some instances, known structures and devices are shown in block diagram form in order to avoid obscuring the concepts of the described examples.

[0235] The description herein is provided to enable a person having ordinary skill in the art to make or use the disclosure. Various modifications to the disclosure will be apparent to a person having ordinary skill in the art, and the generic principles defined herein may be applied to other variations without departing from the scope of the disclosure. Thus, the disclosure is not limited to the examples and designs described herein but is to be accorded the broadest scope consistent with the principles and novel features disclosed herein.

Claims

CLAIMSWhat is claimed is:1 . An apparatus for wireless communication at a first user equipment (UE), comprising: a processor; memory coupled with the processor; and instructions stored in the memory and executable by the processor to cause the apparatus to: receive signaling that indicates a configuration for one or more discovery reference signal windows, the one or more discovery reference signal windows comprising two or more synchronization signal block reception occasions and two or more synchronization signal block transmission occasions in accordance with the configuration; monitor, based at least in part on the configuration, for a reception of a first sidelink synchronization signal block message from a second UE during the two or more synchronization signal block reception occasions of the one or more discovery reference signal windows; and transmit, based at least in part on the configuration, a second sidelink synchronization signal block message to a third UE during at least one synchronization signal block transmission occasion of the two or more synchronization signal block transmission occasions of the one or more discovery reference signal windows.

2. The apparatus of claim 1, wherein, to receive the signaling that indicates the configuration, the instructions are executable by the processor to cause the apparatus to: receive signaling that indicates a reception discovery reference signal window that comprises the two or more synchronization signal block reception occasions and a transmission discovery reference signal window that comprises the two or more synchronization signal block transmission occasions.

3. The apparatus of claim 2, wherein resources of the reception discovery reference signal window and resources of the transmission discovery reference signal window are non-overlapping in a time domain.

4. The apparatus of claim 2, wherein resources of the reception discovery reference signal window and resources of the transmission discovery reference signal window are at least partially overlapping in a time domain.

5. The apparatus of claim 4, wherein at least one of the synchronization signal block reception occasions is positioned between at least two of the synchronization signal block transmission occasions in a time domain.

6. The apparatus of claim 2, wherein resources of the reception discovery reference signal window and resources of the transmission discovery reference signal window are non-overlapping in a frequency domain.

7. The apparatus of claim 1, wherein, to receive the signaling that indicates the configuration, the instructions are executable by the processor to cause the apparatus to: receive signaling that indicates a discovery reference signal window that comprises the two or more synchronization signal block reception occasions and the two or more synchronization signal block transmission occasions.

8. The apparatus of claim 7, wherein at least one of the synchronization signal block reception occasions is positioned between at least two of the synchronization signal block transmission occasions in a time domain.

9. The apparatus of claim 1, wherein, to receive the signaling that indicates the configuration, the instructions are executable by the processor to cause the apparatus to: receive an indication of a first quantity of the two or more synchronization signal block transmission occasions, a second quantity of the two or more synchronization signal block reception occasions, or both the first quantity and the second quantity.

10. The apparatus of claim 1 , wherein, to receive the signaling that indicates the configuration, the instructions are executable by the processor to cause the apparatus to: receive an indication of a separation within a time domain between a first synchronization signal block occasion and a second synchronization signal block occasion of the one or more discovery reference signal windows.

11. The apparatus of claim 10, wherein the indication of the separation indicates a quantity of slots.

12. The apparatus of claim 11, wherein the indicated quantity of slots is zero.

13. The apparatus of claim 1, wherein the instructions are further executable by the processor to cause the apparatus to: perform a listen-before-talk procedure during the one or more discovery reference signal windows, wherein the instructions are executable by the processor to cause the apparatus to transmit the second sidelink synchronization signal block message in response to clearing the listen-before-talk procedure.

14. The apparatus of claim 1, wherein the instructions are further executable by the processor to cause the apparatus to: receive, from the second UE based at least in part on the monitoring, the first sidelink synchronization signal block message, wherein the instructions are executable by the processor to cause the apparatus to transmit the second sidelink synchronization signal block message during at least one synchronization signal block transmission occasion in response to receiving the first sidelink synchronization signal block message during at least one of the two or more synchronization signal block reception occasions.

15. The apparatus of claim 1, wherein the instructions are further executable by the processor to cause the apparatus to: determine that a synchronization accuracy of the first UE satisfies a synchronization accuracy threshold, wherein the instructions are executable by the processor to cause the apparatus to transmit the second sidelink synchronization signalblock message in response to determining that the synchronization accuracy of the first UE satisfies the synchronization accuracy threshold.

16. The apparatus of claim 1, wherein each of the two or more synchronization signal block reception occasions and each of the two or more synchronization signal block transmission occasions corresponds to a respective slot of the one or more discovery reference signal windows.

17. An apparatus for wireless communication at a first user equipment (UE), comprising: a processor; memory coupled with the processor; and instructions stored in the memory and executable by the processor to cause the apparatus to: receive signaling that indicates a configuration for one or more discovery reference signal windows that each comprise a first synchronization signal block occasion for transmission of a first sidelink synchronization signal block message by a second UE, a second synchronization signal block occasion for transmission of a second sidelink synchronization signal block message by the first UE, and a set of additional synchronization signal block transmission occasions configured for use by any UE of a set of UEs comprising the first UE and the second UE; monitor, based at least in part on the configuration, for transmission of the first sidelink synchronization signal block message by the second UE during the first synchronization signal block occasion of the one or more discovery reference signal windows; and attempt, based at least in part on the configuration, to transmit the second sidelink synchronization signal block message during the second synchronization signal block occasion of the one or more discovery reference signal windows, wherein: whether the first UE monitors for transmission of the first sidelink synchronization signal block message by the second UE during the set of additional synchronization signal block transmission occasions be based at least in part on whether the first sidelink synchronizationsignal block message is received by the first UE during the first synchronization signal block occasion; and whether the first UE transmits the second sidelink synchronization signal block message during the set of additional synchronization signal block transmission occasions is based at least in part on whether the second sidelink synchronization signal block message is transmitted by the first UE during the second synchronization signal block occasion.

18. The apparatus of claim 17, wherein: to attempt to transmit the second sidelink synchronization signal block message during the second synchronization signal block occasion, the instructions are further executable by the processor to cause the apparatus to perform a listen-before-talk procedure during the second synchronization signal block occasion; and the instructions are further executable by the processor to cause the apparatus to transmit the second sidelink synchronization signal block message during a synchronization signal block transmission occasion of the set of additional synchronization signal block transmission occasions based at least in part on a failure of the listen-before-talk procedure during the second synchronization signal block occasion.

19. The apparatus of claim 17, wherein the instructions are further executable by the processor to cause the apparatus to: determine an absence of the first sidelink synchronization signal block message from the first synchronization signal block occasion based at least in part on the monitoring during the first synchronization signal block occasion; and monitor for transmission of the first sidelink synchronization signal block message by the second UE during a synchronization signal block transmission occasion of the set of additional synchronization signal block transmission occasions based at least in part on the absence of the first sidelink synchronization signal block message from the first synchronization signal block occasion.

20. The apparatus of claim 17, wherein the instructions are further executable by the processor to cause the apparatus to:determine that a synchronization accuracy of the first UE does is lower than a synchronization accuracy threshold; and monitor for transmission of the first sidelink synchronization signal block message by the second UE during a synchronization signal block transmission occasion of the set of additional synchronization signal block transmission occasions based at least in part on determining that the synchronization accuracy of the first UE is lower than the synchronization accuracy threshold.

21. The apparatus of claim 17, wherein the instructions are further executable by the processor to cause the apparatus to: receive the first sidelink synchronization signal block message during a first additional synchronization signal block transmission occasion of the set of additional synchronization signal block transmission occasions; and transmit the second sidelink synchronization signal block message during a second additional synchronization signal block transmission occasion of the set of additional synchronization signal block transmission occasions based at least in part on receiving the first sidelink synchronization signal block message during the first additional synchronization signal block transmission occasion.

22. The apparatus of claim 17, wherein each of the first synchronization signal block occasion, the second synchronization signal block occasion, and the additional synchronization signal block transmission occasions corresponds to a respective slot of the one or more discovery reference signal windows.

23. A method for wireless communication at a first user equipment (UE), comprising: receiving signaling that indicates a configuration for one or more discovery reference signal windows, the one or more discovery reference signal windows comprising two or more synchronization signal block reception occasions and two or more synchronization signal block transmission occasions in accordance with the configuration; monitoring, based at least in part on the configuration, for a reception of a first sidelink synchronization signal block message from a second UE during the twoor more synchronization signal block reception occasions of the one or more discovery reference signal windows; and transmitting, based at least in part on the configuration, a second sidelink synchronization signal block message to a third UE during at least one synchronization signal block transmission occasion of the two or more synchronization signal block transmission occasions of the one or more discovery' reference signal windows.

24. The method of claim 23, wherein receiving the signaling that indicates the configuration comprises: receiving signaling that indicates a reception discovery reference signal window that comprises the two or more synchronization signal block reception occasions and a transmission discovery reference signal window that includes the two or more synchronization signal block transmission occasions.

25. The method of claim 23, wherein receiving the signaling that indicates the configuration comprises: receiving signaling that indicates a discovery reference signal window that comprises the two or more synchronization signal block reception occasions and the two or more synchronization signal block transmission occasions.

26. The method of claim 23, wherein receiving the signaling that indicates the configuration comprises: receiving an indication of a first quantity of the two or more synchronization signal block transmission occasions, a second quantity of the two or more synchronization signal block reception occasions, or both the first quantity and the second quantity.

27. A method for wireless communication at a first user equipment (UE), comprising: receiving signaling that indicates a configuration for one or more discovery reference signal windows that each comprise a first synchronization signal block occasion for transmission of a first sidelink synchronization signal block message by a second UE, a second synchronization signal block occasion for transmission of a second sidelink synchronization signal block message by the first UE, and a set ofadditional synchronization signal block transmission occasions configured for use by any UE of a set of UEs comprising the first UE and the second UE; monitoring, based at least in part on the configuration, for transmission of the first sidelink synchronization signal block message by the second UE during the first synchronization signal block occasion of the one or more discovery reference signal windows; and attempting, based at least in part on the configuration, to transmit the second sidelink synchronization signal block message during the second synchronization signal block occasion of the one or more discovery reference signal windows, wherein: whether the first UE monitors for transmission of the first sidelink synchronization signal block message by the second UE during the set of additional synchronization signal block transmission occasions is based at least in part on whether the first sidelink synchronization signal block message is received by the first UE during the first synchronization signal block occasion; and whether the first UE transmits the second sidelink synchronization signal block message during the set of additional synchronization signal block transmission occasions is based at least in part on whether the second sidelink synchronization signal block message is transmitted by the first UE during the second synchronization signal block occasion.

28. The method of claim 27, wherein attempting to transmit the second sidelink synchronization signal block message during the second synchronization signal block occasion comprises performing a listen-before-talk procedure during the second synchronization signal block occasion, the method further comprising: transmitting the second sidelink synchronization signal block message during a synchronization signal block transmission occasion of the set of additional synchronization signal block transmission occasions based at least in part on a failure of the listen-before-talk procedure during the second synchronization signal block occasion.

29. The method of claim 27, further comprising: determining an absence of the first sidelink synchronization signal block message from the first synchronization signal block occasion based at least in part on the monitoring during the first synchronization signal block occasion; and monitoring for transmission of the first sidelink synchronization signal block message by the second UE during a synchronization signal block transmission occasion of the set of additional synchronization signal block transmission occasions based at least in part on the absence of the first sidelink synchronization signal block message from the first synchronization signal block occasion.

30. The method of claim 27, further comprising: determining that a synchronization accuracy of the first UE does is lower than a synchronization accuracy threshold; and monitoring for transmission of the first sidelink synchronization signal block message by the second UE during a synchronization signal block transmission occasion of the set of additional synchronization signal block transmission occasions based at least in part on determining that the synchronization accuracy of the first UE is lower than the synchronization accuracy threshold.

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