Discovery reference signal window configuration for sidelink

Abstract

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

Description

[0001] Cross-references

[0002] This patent application claims priority to Greek patent application No. 20220100680, entitled "DISCOVERY REFERENCESIGNAL WINDOW CONFIGURATION FOR SIDELINK", filed by LIU et al. on August 11, 2022, which is assigned to the assignee of this application and is expressly incorporated herein by reference. Technical Field

[0003] The following relates to wireless communications, including discovery reference signal window configuration for a sidelink. Background Art

[0004] Wireless communication systems are widely deployed to provide various types of communication content, such as voice, video, packet data, messaging, broadcast, and the like. These systems may be able to support communication with multiple users by sharing 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, advanced LTE (LTE-A) systems, or LTE-A Pro systems) and fifth generation (5G) systems (which may be referred to as new radio (NR) systems). These systems may employ techniques such as code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), orthogonal FDMA (OFDMA), or discrete Fourier transform spread orthogonal frequency division multiplexing (DFT-S-OFDM). A wireless multiple access communication system may include one or more base stations, each of which supports wireless communications for communication devices, which may be referred to as user equipment (UE).

[0005] A wireless communication system may support communication between UEs, and such communication may be referred to as sidelink communication. In some cases, a first UE may relay control information and data from a network to a second UE using a sidelink channel. The second UE may be out of coverage of the network, and the sidelink communication technology may support communication between the second UE and the network. Summary of the invention

[0006] The described technology relates to improved methods, systems, devices and apparatuses that support configuration of discovery reference signal windows for sidelinks. For example, the described technology provides a user equipment (UE) that supports the use of a sidelink channel to communicate synchronization information to other UEs via a sidelink synchronization signal block (SSB). The UE may be configured with one or more discovery reference signal (DRS) windows, and the one or more discovery reference signal (DRS) windows include multiple S-SSB reception opportunities and multiple S-SSB transmission opportunities. The UE may monitor the transmission of an S-SSB on a first sidelink channel during the reception opportunity, and transmit the S-SSB on a second sidelink channel during the transmission opportunity. Therefore, this configuration of the one or more DRS windows can support the use of a sidelink channel to communicate the synchronization information to multiple UEs.

[0007] A method for wireless communication at a first user equipment (UE) is described. The method may include: receiving signaling indicating a configuration for one or more discovery reference signal windows, according to which the one or more discovery reference signal windows include two or more synchronization signal block reception opportunities and two or more synchronization signal block transmission opportunities; based on the configuration, monitoring the reception of a first side link synchronization signal block message from a second UE during the two or more synchronization signal block reception opportunities of the one or more discovery reference signal windows; and based on the configuration, sending a second side link synchronization signal block message to a third UE during at least one of the two or more synchronization signal block transmission opportunities of the one or more discovery reference signal windows.

[0008] A device for wireless communication at a first UE is described. The device may include a processor, a memory coupled to the processor, and instructions stored in the memory. The instructions may be executable by the processor to cause the device to: receive signaling indicating a configuration for one or more discovery reference signal windows, according to which the one or more discovery reference signal windows include two or more synchronization signal block reception opportunities and two or more synchronization signal block transmission opportunities; based on the configuration, monitor the reception of a first side link synchronization signal block message from a second UE during the two or more synchronization signal block reception opportunities of the one or more discovery reference signal windows; and based on the configuration, send a second side link synchronization signal block message to a third UE during at least one of the two or more synchronization signal block transmission opportunities of the one or more discovery reference signal windows.

[0009] Another apparatus for wireless communication at a first UE is described. The apparatus may include: a component for receiving signaling indicating a configuration for one or more discovery reference signal windows, according to which the one or more discovery reference signal windows include two or more synchronization signal block reception opportunities and two or more synchronization signal block transmission opportunities; a component for monitoring the reception of a first sidelink synchronization signal block message from a second UE during the two or more synchronization signal block reception opportunities of the one or more discovery reference signal windows based on the configuration; and a component for sending a second sidelink synchronization signal block message to a third UE during at least one of the two or more synchronization signal block transmission opportunities of the one or more discovery reference signal windows based on the configuration.

[0010] A non-transitory computer-readable medium storing code for wireless communication at a first UE is described. The code may include instructions that can be executed by a processor to: receive signaling indicating a configuration for one or more discovery reference signal windows, according to which the one or more discovery reference signal windows include two or more synchronization signal block reception opportunities and two or more synchronization signal block transmission opportunities; based on the configuration, monitor the reception of a first side link synchronization signal block message from a second UE during the two or more synchronization signal block reception opportunities of the one or more discovery reference signal windows; and based on the configuration, send a second side link synchronization signal block message to a third UE during at least one of the two or more synchronization signal block transmission opportunities of the one or more discovery reference signal windows.

[0011] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, receiving the signaling indicating the configuration may include operations, features, components, or instructions for the following actions: receiving signaling indicating a receive discovery reference signal window and a send discovery reference signal window, the receive discovery reference signal window including the two or more synchronization signal block receive opportunities, and the send discovery reference signal window including the two or more synchronization signal block send opportunities.

[0012] In some examples of the methods, apparatuses, and non-transitory computer-readable media described herein, the resources of the reception discovery reference signal window and the resources of the transmission discovery reference signal window may not overlap in the time domain.

[0013] In some examples of the methods, apparatuses, and non-transitory computer-readable media described herein, the resources of the reception discovery reference signal window and the resources of the transmission discovery reference signal window may at least partially overlap in the time domain.

[0014] In some examples of the methods, devices, and non-transitory computer-readable media described herein, at least one of the synchronization signal block reception opportunities can be positioned in the time domain between at least two of the synchronization signal block transmission opportunities.

[0015] In some examples of the methods, apparatuses, and non-transitory computer-readable media described herein, the resources of the reception discovery reference signal window and the resources of the transmission discovery reference signal window may not overlap in the frequency domain.

[0016] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, receiving the signaling indicating the configuration may include operations, features, components, or instructions for the following actions: receiving signaling indicating a discovery reference signal window, the discovery reference signal window including the two or more synchronization signal block reception opportunities and the two or more synchronization signal block transmission opportunities.

[0017] In some examples of the methods, devices, and non-transitory computer-readable media described herein, at least one of the synchronization signal block reception opportunities can be positioned in the time domain between at least two of the synchronization signal block transmission opportunities.

[0018] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, receiving the signaling indicating the configuration may include operations, features, components, or instructions for receiving an indication of a first number of opportunities for sending the two or more synchronization signal blocks, a second number of opportunities for receiving the two or more synchronization signal blocks, or both the first number and the second number.

[0019] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, receiving the signaling indicating the configuration may include operations, features, components, or instructions for receiving an indication of a spacing in the time domain between a first synchronization signal block opportunity and a second synchronization signal block opportunity of the one or more discovery reference signal windows.

[0020] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, the indication of the spacing indicates a number of time slots.

[0021] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, the indicated number of time slots may be zero.

[0022] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, components, or instructions for performing a listen-before-talk procedure during the one or more discovery reference signal windows, wherein the first UE sends the second side link synchronization signal block message in response to clearing the listen-before-talk procedure.

[0023] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, components, or instructions for the following actions: based on the monitoring, receiving the first side link synchronization signal block message from the second UE, wherein the first UE sends the second side link synchronization signal block message during at least one synchronization signal block sending opportunity in response to receiving the first side link synchronization signal block message during at least one synchronization signal block receiving opportunity among the two or more synchronization signal block receiving opportunities.

[0024] Some examples of the methods, devices, and non-transitory computer-readable media described herein may also include operations, features, components, or instructions for the following actions: determining that the synchronization accuracy of the first UE satisfies a synchronization accuracy threshold, wherein the first UE sends the second side link synchronization signal block message in response to determining that the synchronization accuracy of the first UE satisfies the synchronization accuracy threshold.

[0025] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, each of the two or more synchronization signal block reception opportunities and each of the two or more synchronization signal block transmission opportunities correspond to corresponding time slots of the one or more discovery reference signal windows.

[0026] A method for wireless communication at a first UE is described. The method may include: receiving signaling indicating a configuration for one or more discovery reference signal windows, each of the one or more discovery reference signal windows including a first synchronization signal block opportunity, a second synchronization signal block opportunity, and an additional synchronization signal block transmission opportunity set, the first synchronization signal block opportunity being used by the second UE to send a first side link synchronization signal block message, the second synchronization signal block opportunity being used by the first UE to send a second side link synchronization signal block message, and the additional synchronization signal block transmission opportunity set being configured to be used by any UE in a UE set including the first UE and the second UE; based on the configuration, monitoring the first synchronization signal block opportunity during the first synchronization signal block opportunity of the one or more discovery reference signal windows. The second UE sends the first side link synchronization signal block message; based on the configuration, attempt to send the second side link synchronization signal block message during the second synchronization signal block opportunity of the one or more reference signal discovery windows, wherein whether the first UE monitors the sending of the first side link synchronization signal block message by the second UE during the additional synchronization signal block sending opportunity set is based on whether the first UE receives the first side link synchronization signal block message during the first synchronization signal block opportunity; and wherein whether the first UE sends the second side link synchronization signal block message during the additional synchronization signal block sending opportunity set is based on whether the first UE sends the second side link synchronization signal block message during the second synchronization signal block opportunity.

[0027] A device for wireless communication at a first UE is described. The device may include a processor, a memory coupled to the processor, and instructions stored in the memory. The instructions may be executable by the processor to cause the device to: receive signaling indicating a configuration for one or more discovery reference signal windows, each of the one or more discovery reference signal windows including a first synchronization signal block opportunity, a second synchronization signal block opportunity, and an additional synchronization signal block sending opportunity set, the first synchronization signal block opportunity being used for the second UE to send a first side link synchronization signal block message, the second synchronization signal block opportunity being used for the first UE to send a second side link synchronization signal block message, and the additional synchronization signal block sending opportunity set being configured to be used by any UE in a UE set including the first UE and the second UE; based on the configuration, at the first synchronization signal block opportunity of the one or more discovery reference signal windows The first UE monitors the sending of the first side link synchronization signal block message by the second UE during the additional synchronization signal block sending opportunity set; based on the configuration, attempts to send the second side link synchronization signal block message during the second synchronization signal block opportunity of the one or more discovery reference signal windows, wherein whether the first UE monitors the sending of the first side link synchronization signal block message by the second UE during the additional synchronization signal block sending opportunity set is based on whether the first UE receives the first side link synchronization signal block message during the first synchronization signal block opportunity; and wherein whether the first UE sends the second side link synchronization signal block message during the additional synchronization signal block sending opportunity set is based on whether the first UE sends the second side link synchronization signal block message during the second synchronization signal block opportunity.

[0028] Another apparatus for wireless communication at a first UE is described. The apparatus may include: a component for receiving signaling indicating a configuration for one or more discovery reference signal windows, each of the one or more discovery reference signal windows including a first synchronization signal block opportunity, a second synchronization signal block opportunity, and an additional synchronization signal block transmission opportunity set, the first synchronization signal block opportunity being used by a second UE to send a first sidelink synchronization signal block message, the second synchronization signal block opportunity being used by the first UE to send a second sidelink synchronization signal block message, and the additional synchronization signal block transmission opportunity set being configured to be used by any UE in a UE set including the first UE and the second UE; and a component for monitoring the first synchronization signal block opportunity of the one or more discovery reference signal windows during the first synchronization signal block opportunity based on the configuration. A component for the second UE to send the first side link synchronization signal block message; a component for attempting to send the second side link synchronization signal block message during the second synchronization signal block opportunity of the one or more reference signal discovery windows based on the configuration, wherein whether the first UE monitors the sending of the first side link synchronization signal block message by the second UE during the additional synchronization signal block sending opportunity set is based on whether the first UE receives the first side link synchronization signal block message during the first synchronization signal block opportunity; and wherein whether the first UE sends the second side link synchronization signal block message during the additional synchronization signal block sending opportunity set is based on whether the first UE sends the second side link synchronization signal block message during the second synchronization signal block opportunity.

[0029] A non-transitory computer-readable medium storing code for wireless communication at a first UE is described. The code may include instructions that can be executed by a processor to: receive signaling indicating a configuration for one or more discovery reference signal windows, each of the one or more discovery reference signal windows including a first synchronization signal block opportunity, a second synchronization signal block opportunity, and an additional synchronization signal block transmission opportunity set, the first synchronization signal block opportunity is used by the second UE to send a first side link synchronization signal block message, the second synchronization signal block opportunity is used by the first UE to send a second side link synchronization signal block message, and the additional synchronization signal block transmission opportunity set is configured to be used by any UE in a UE set including the first UE and the second UE; based on the configuration, in the first synchronization signal block of the one or more discovery reference signal windows, The first UE monitors the sending of the first side link synchronization signal block message by the second UE during the additional synchronization signal block sending opportunity set; based on the configuration, attempts to send the second side link synchronization signal block message during the second synchronization signal block opportunity of the one or more discovery reference signal windows, wherein whether the first UE monitors the sending of the first side link synchronization signal block message by the second UE during the additional synchronization signal block sending opportunity set is based on whether the first UE receives the first side link synchronization signal block message during the first synchronization signal block opportunity; and wherein whether the first UE sends the second side link synchronization signal block message during the additional synchronization signal block sending opportunity set is based on whether the first UE sends the second side link synchronization signal block message during the second synchronization signal block opportunity.

[0030] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, attempting to send the second side link synchronization signal block message during the second synchronization signal block opportunity includes performing a listen-before-talk procedure during the second synchronization signal block opportunity, and the methods, apparatus, and non-transitory computer-readable media may also include operations, features, components, or instructions for the following actions: based on the failure of the listen-before-talk procedure during the second synchronization signal block opportunity, sending the second side link synchronization signal block message during a synchronization signal block transmission opportunity in the additional synchronization signal block transmission opportunity set.

[0031] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, components, or instructions for: determining, based on the monitoring during the first synchronization signal block opportunity, that the first side link synchronization signal block message does not exist in the first synchronization signal block opportunity; and monitoring, based on the absence of the first side link synchronization signal block message in the first synchronization signal block opportunity, the sending of the first side link synchronization signal block message by the second UE during the synchronization signal block sending opportunities in the additional synchronization signal block sending opportunity set.

[0032] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, components, or instructions for: determining that the synchronization accuracy of the first UE may be lower than a synchronization accuracy threshold; and based on determining that the synchronization accuracy of the first UE may be lower than the synchronization accuracy threshold, monitoring the second UE's sending of the first side link synchronization signal block message during a synchronization signal block sending opportunity in the additional synchronization signal block sending opportunity set.

[0033] Some examples of the methods, apparatus, and non-transitory computer-readable media described herein may also include operations, features, components, or instructions for: receiving the first side link synchronization signal block message during a first additional synchronization signal block transmission opportunity in the additional synchronization signal block transmission opportunity set; and sending the second side link synchronization signal block message during a second additional synchronization signal block transmission opportunity in the additional synchronization signal block transmission opportunity set based on receiving the first side link synchronization signal block message during the first additional synchronization signal block transmission opportunity.

[0034] In some examples of the methods, apparatus, and non-transitory computer-readable media described herein, each of the first synchronization signal block opportunity, the second synchronization signal block opportunity, and the additional synchronization signal block transmission opportunity corresponds to a corresponding time slot of the one or more discovery reference signal windows. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 An example of a wireless communication system supporting a discovery reference signal window configuration for a sidelink according to one or more aspects of the present disclosure is illustrated.

[0036] Figure 2 An example of a wireless communication system supporting a discovery reference signal window configuration for a sidelink according to one or more aspects of the present disclosure is illustrated.

[0037] Figure 3A and Figure 3B An example of a resource diagram supporting a discovery reference signal window configuration for a sidelink according to one or more aspects of the present disclosure is illustrated.

[0038] Figure 4 An example of a resource diagram supporting a discovery reference signal window configuration for a sidelink according to one or more aspects of the present disclosure is illustrated.

[0039] Figure 5 An example of a process flow supporting discovery reference signal window configuration for a sidelink according to one or more aspects of the present disclosure is illustrated.

[0040] Figure 6An example of a process flow supporting discovery reference signal window configuration for a sidelink according to one or more aspects of the present disclosure is illustrated.

[0041] Figure 7 and Figure 8 A block diagram of a device supporting discovery reference signal window configuration for a sidelink according to one or more aspects of the present disclosure is shown.

[0042] Fig. 9 A block diagram of a communication manager supporting discovery reference signal window configuration for a sidelink is shown in accordance with one or more aspects of the present disclosure.

[0043] Fig.10 A diagram of a system including a device supporting discovery reference signal window configuration for a sidelink is shown in accordance with one or more aspects of the present disclosure.

[0044] Figures 11 to 14 A flow chart illustrating a method of supporting discovery reference signal window configuration for a sidelink according to one or more aspects of the present disclosure is shown. DETAILED DESCRIPTION

[0045] A wireless communication system may support sidelink communications (e.g., vehicle-to-everything (V2X) communications) between user equipment (UEs). In some examples, the UEs may share a sidelink synchronization block (S-SSB) to support synchronization of the UEs receiving the S-SSBs with a network entity. Some of the transmissions of the S-SSBs may be performed during a configured discovery reference signal (DRS) window. For example, a UE within the coverage of a trusted synchronization source (e.g., the network entity) may receive synchronization information from the network entity. In order to benefit neighboring UEs that are not within the coverage of the network entity and therefore do not receive the synchronization information, the UE may become an S-SSB sender (e.g., a first synchronization reference (syncRef) node) and send the S-SSBs containing the synchronization information from the network entity to the neighboring UEs.

[0046] One of the neighboring UEs (the second UE) may receive the S-SSBs from the first syncRef node and use the S-SSBs to synchronize with the network entity. In some examples, the second UE may determine to also send an S-SSB to another neighboring UE (the third UE) (becoming the second syncRef node) based on some thresholds and criteria (e.g., the distance between the two UEs). Thus, the synchronization information may continue to propagate through the system. However, half-duplex limitations at these UEs (e.g., the second UE) may limit the ability of these UEs to efficiently receive and / or send S-SSBs without interfering with other communications. Additionally, due to the listen-before-talk (LBT) uncertainty in the system, the syncRef node may use additional opportunities to send these S-SSBs.

[0047] In order to support S-SSB transmission and reception in a wireless communication system that may include a half-duplex UE, the technology described herein supports the configuration of one or more DRS windows, which include multiple S-SSB transmission opportunities and multiple S-SSB reception opportunities. In one example, two DRS window configurations may be defined, wherein the first DRS window includes multiple S-SSB reception opportunities (e.g., resources), and the second DRS window includes multiple S-SSB transmission opportunities (e.g., resources). The two DRS windows may be continuous, non-overlapping, or time-combined (e.g., interleaved). In another example, a DRS window may be configured so as to include S-SSB transmission opportunities and S-SSB transmission reception opportunities (e.g., in an interleaved mode). Therefore, two DRS windows may be configured for a UE, one for receiving S-SSBs by the UE and the other for sending S-SBSs by the UE.

[0048] In some cases, a configuration of a single DRS window may be used, wherein the single DRS window includes a first time slot for sending an S-SSB by a first syncRef node (e.g., an upstream node), a second time slot for sending an S-SSB by a second syncRef node (e.g., a downstream node), and a set of S-SSB opportunities that can be used for S-SSB reception or S-SSB transmission (referred to as additional SSB transmission opportunities). Additionally, the first syncRef node may be restricted from transmitting during the second time slot. Thus, a single DRS window may be configured in which different S-SSB opportunities are assigned to different UEs as S-SSB transmission opportunities (subject to the LBT of the assigned UEs, one or other of which monitors to potentially receive the S-SSB), and the single DRS window may also include one or more additional S-SSB opportunities that any UE may use to transmit, depending on whether the UE is able to transmit earlier during its assigned S-SSB opportunity in the DRS window. In some such cases, if LBT fails in a legacy time slot, the second syncRef node may not receive timing from the first syncRef node. To prevent possible timing issues, if the timing / frequency accuracy is determined to be below a threshold, the second syncRef may monitor the S-SSB from the first syncRef node before starting an S-SSB transmission, thereby forgoing a transmission opportunity until the S-SSB transmission is more likely to be accurate.

[0049] Various aspects of the disclosure are first described in the context of a wireless communication system. Various aspects of the disclosure are further described with respect to a wireless communication system that illustrates sidelink communication and network synchronization, resource diagrams, and process flow diagrams. Various aspects of the disclosure are further illustrated by and described with reference to apparatus diagrams, system diagrams, and flow diagrams related to discovery reference signal window configuration for a sidelink.

[0050] Figure 1 An example of a wireless communication system 100 supporting a discovery reference signal window configuration for a sidelink according to one or more aspects of the present disclosure is illustrated. The wireless communication 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 communication system 100 may be a long term evolution (LTE) network, an advanced LTE (LTE-A) network, an LTE-A Pro network, a new radio (NR) network, or a network operating according to other systems and radio technologies (including future systems and radio technologies not explicitly mentioned herein).

[0051] The network entities 105 may be dispersed throughout a geographic area to form the wireless communication system 100 and may include devices in different forms or with different capabilities. In various examples, the network entities 105 may be referred to as network elements, mobility elements, radio access network (RAN) nodes, or network equipment, etc. In some examples, the network entities 105 and the UE 115 may communicate wirelessly via one or more communication links 125 (e.g., radio frequency (RF) access links). For example, the network entity 105 may support a coverage area 110 (e.g., a geographic coverage area) within which the UE 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 within which the network entity 105 and the UE 115 may support signal communications according to one or more radio access technologies (RATs).

[0052] The UEs 115 may be dispersed throughout the coverage area 110 of the wireless communication system 100, and each UE 115 may be stationary or mobile, or stationary and mobile at different times. The UEs 115 may be devices that take different form factors or have different capabilities. Figure 1 Some example UEs 115 are illustrated in FIG. 1. The UEs 115 described herein may be capable of supporting communication with various types of devices, such as Figure 1 Communicate with other UEs 115 or network entities 105) as shown.

[0053] As described herein, a node of the wireless communication 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 the techniques described herein. For example, the node may be a UE 115. As another example, the 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 other aspects of this example, the first node, the second node, and the third node may be different relative to these examples. Similarly, references to UE 115, network entity 105, apparatus, device, or computing system, etc. may include disclosure of UE 115, network entity 105, apparatus, device, or computing system, etc. as nodes. For example, disclosure that UE 115 is configured to receive information from network entity 105 also discloses that the first node is configured to receive information from the second node.

[0054] In some examples, the network entities 105 may communicate with the core network 130, or with each other, or both. For example, the network entities 105 may communicate with the core network 130 via one or more backhaul communication links 120 (e.g., according to S1, N2, N3, or other interface protocols). In some examples, the network entities 105 may communicate with each other via the backhaul communication links 120 (e.g., according to X2, Xn, or other interface protocols) directly (e.g., directly between the network entities 105) or indirectly (e.g., via the core network 130). In some examples, the network entities 105 may communicate with each other via the midhaul communication links 162 (e.g., according to the midhaul interface protocol) or the fronthaul communication links 168 (e.g., according to the fronthaul interface protocol) or any combination thereof. The backhaul communication links 120, the midhaul communication links 162, or the fronthaul communication links 168 may be or include one or more wired links (e.g., electrical links, optical fiber links), one or more wireless links (e.g., radio links, wireless optical links), etc. or various combinations thereof. UE 115 may communicate with core network 130 via communication link 155 .

[0055] 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 transceiver base station, a radio base station, an NR base station, an access point, a radio transceiver, a Node B, an evolved Node B (eNB), a next generation Node B, or a Gigabit Node B (any of which may be referred to as a gNB), a 5G NB, a next generation eNB (ng-eNB), a Home Node B, a Home Evolved Node B, or other suitable terms). In some examples, the 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 physically or logically integrated within a single network entity 105 (e.g., a single RAN node, such as a base station 140).

[0056] In some examples, the network entity 105 may be implemented in a disaggregated architecture (e.g., a disaggregated base station architecture, a disaggregated RAN architecture) that may be configured to utilize a protocol stack that is physically or logically distributed between two or more network entities 105, such as an integrated access backhaul (IAB) 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, the network entity 105 may include one or more of the following: 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), a non-real-time RIC (non-RT RIC)), a service management and orchestration (SMO) 180 system, or any combination thereof. The 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 transmit receive point (TRP). One or more components of the network entity 105 in the decomposed RAN architecture may be co-located, or one or more components of the network entity 105 may be located in distributed locations (e.g., separate physical locations). In some examples, one or more network entities 105 of the decomposed RAN architecture may be implemented as virtual units (e.g., virtual CU (VCU), virtual DU (VDU), virtual RU (VRU)).

[0057] The functional split between CU 160, DU 165, and 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 combination thereof) are performed at CU 160, DU 165, or RU 170. For example, a functional split of a protocol stack may be employed between CU 160 and DU 165 such that CU 160 may support one or more layers of a protocol stack and DU 165 may support one or more different layers of a protocol stack. In some examples, CU 160 may host higher protocol layer (e.g., layer 3 (L3), layer 2 (L2)) functionality and signaling (e.g., radio resource control (RRC), service data adaptation 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 (L1) (e.g., physical (PHY) layer) or L2 (e.g., radio link control (RLC) layer, medium access control (MAC) layer) functionality and signaling, and each may be at least partially controlled by the CU 160. Additionally or alternatively, a functional split of the protocol stack may be employed between the DU 165 and the 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 more different cells (e.g., via one or more RUs 170). In some cases, the functional split between CU 160 and DU 165 or between DU 165 and RU 170 may be within the protocol layer (e.g., some functions of the protocol layer may be performed by one of CU 160, DU 165, or RU 170, while other functions of the protocol layer are performed by different ones of CU 160, DU 165, or RU 170). CU 160 may be further functionally split into CU control plane (CU-CP) and CU user plane (CU-UP) functions. CU 160 may be connected to one or more DUs 165 via midhaul communication links 162 (e.g., F1, F1-c, F1-u), and DU 165 may be connected to one or more RUs 170 via fronthaul communication links 168 (e.g., open fronthaul (FH) interface). In some examples, midhaul communication link 162 or fronthaul communication link 168 may be implemented based on an interface (e.g., a channel) between layers of a protocol stack supported by respective network entities 105 that communicate via such communication links.

[0058] In some wireless communication systems (e.g., wireless communication system 100), infrastructure and spectrum resources for radio access may support wireless backhaul link capabilities to supplement wired backhaul connections, thereby providing an IAB network architecture (e.g., to core network 130). In some cases, in an IAB 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 donor entities or IAB donors. One or more DUs 165 or one or more RUs 170 may be controlled in part by one or more CUs 160 associated with a donor network entity 105 (e.g., a donor base station 140). One or more donor network entities 105 (e.g., IAB donors) may communicate 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). The IAB node 104 may include an IAB mobile terminal (IAB-MT) controlled (e.g., scheduled) by a coupled IAB donor's DU 165. The IAB-MT may include an independent set of antennas for relaying communications with the UE 115, or may share the same antennas of the IAB node 104 (e.g., of the RU 170) for access via the DU 165 of the IAB node 104 (e.g., referred to as a virtual IAB-MT (vIAB-MT)). In some examples, the IAB node 104 may include a DU 165 that supports communication links with additional entities (e.g., IAB node 104, UE 115) within a relay chain or configuration (e.g., downstream) of the access network. In such cases, one or more components of the decomposed RAN architecture (e.g., one or more IAB nodes 104 or components of the IAB node 104) may be configured to operate according to the techniques described herein.

[0059] In the case where the techniques described herein are applied in the context of a decomposed RAN architecture, one or more components of the decomposed RAN architecture may be configured to support the discovery reference signal window configuration for the sidelink as described herein. For example, some operations described as being performed by UE 115 or network entity 105 (e.g., base station 140) may be additionally or alternatively performed by one or more components of the decomposed RAN architecture (e.g., IAB node 104, DU 165, CU 160, RU 170, RIC 175, SMO 180).

[0060] 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 term, where a "device" may also be referred to as a unit, a station, a terminal or a client, etc. 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, UE 115 may include or may be referred to as a wireless local loop (WLL) station, an Internet of Things (IoT) device, an Internet of Everything (IoE) device, or a machine type communication (MTC) device, etc., which may be implemented in various objects such as appliances or vehicles, meters, etc.

[0061] The UE 115 described herein may be capable of communicating with various types of devices, such as other UEs 115, which may sometimes act as relays, as well as network entities 105 and network equipment including macro eNBs or gNBs, small cell eNBs or gNBs, or relay base stations, etc. Figure 1 shown.

[0062] The UE 115 and the network entity 105 may wirelessly communicate with each other via one or more communication links 125 (e.g., access links) using resources associated with one or more carriers. The term "carrier" may refer to a collection of RF spectrum resources having a physical layer structure defined for supporting the communication link 125. For example, a carrier for the communication link 125 may include a portion of an RF spectrum band (e.g., a bandwidth portion (BWP)) that operates according to one or more physical layer channels for a given radio access technology (e.g., LTE, LTE-A, LTE-A Pro, NR). Each physical layer channel may carry acquisition signaling (e.g., synchronization signals, system information), control signaling for coordinating carrier operations, user data, or other signaling. The wireless communication system 100 may support communications with the UE 115 using carrier aggregation or multi-carrier operation. Depending on the carrier aggregation configuration, the UE 115 may be configured with multiple downlink component carriers and one or more uplink component carriers. Carrier aggregation may be used for both frequency division duplex (FDD) and time division duplex (TDD) component carriers. Communication between the network entity 105 and other devices may refer to communication between these devices and any part (e.g., entity, sub-entity) of the network entity 105. For example, the terms "send", "receive", or "communicate" when referring to the network entity 105 may refer to any part of the network entity 105 (e.g., base station 140, CU 160, DU 165, RU 170) of the RAN communicating with another device (e.g., directly or via one or more other network entities 105).

[0063] The communication link 125 shown in the wireless communication system 100 may include downlink transmissions (e.g., forward link transmissions) from the network entity 105 to the UE 115, uplink transmissions (e.g., return link transmissions) from the UE 115 to the network entity 105, or both, as well as other transmission configurations. A carrier may carry downlink communications or uplink communications (e.g., in FDD mode), or may be configured to carry downlink communications and uplink communications (e.g., in TDD mode).

[0064] The signal waveform transmitted via the carrier may include 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 using MCM technology, a resource element may refer to a resource of one symbol period (e.g., the duration of one modulation symbol) and one subcarrier, in which case the symbol period and the subcarrier spacing may be inversely related. The number 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), so that a relatively high number of resource elements (e.g., in the transmission duration) and a relatively high order modulation scheme may correspond to a relatively high rate of communication. Wireless communication resources may refer to a combination of RF spectrum resources, time resources, and spatial resources (e.g., spatial layers, beams), and the use of multiple spatial resources may increase the data rate or data integrity used for communication with UE 115.

[0065] The time interval for the network entity 105 or the UE 115 may be expressed in multiples of a basic time unit, which may be referred to as a sampling period T s =1 / (Δf max ·N f seconds, where Δf max It can represent the supported subcarrier spacing, and N f The supported discrete Fourier transform (DFT) size may be indicated. Time intervals of the communication resources 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).

[0066] Each frame may include multiple consecutively numbered subframes or time slots, and each subframe or time slot may have the same duration. In some examples, the frame may be divided into subframes (e.g., in the time domain), and each subframe may be further divided into a certain number of time slots. Alternatively, each frame may include a variable number of time slots, and the number of time slots may depend on the subcarrier spacing. Each time slot may include a certain number of symbol periods (e.g., depending on the length of the cyclic prefix appended in front of each symbol period). In some wireless communication systems 100, the time slot may be further divided into mini-time slots associated with one or more symbols. Excluding the cyclic prefix, each symbol period may be associated with one or more (e.g., N f The duration of a symbol period may depend on the subcarrier spacing or the operating frequency band.

[0067] A subframe, a time slot, a mini-time slot, or a symbol may be the smallest scheduling unit (e.g., in the time domain) of the wireless communication system 100 and may be referred to as a transmission time interval (TTI). In some examples, the TTI duration (e.g., the number of symbol periods in a TTI) may be variable. Additionally or alternatively, the smallest scheduling unit of the wireless communication system 100 may be dynamically selected (e.g., in a burst of a shortened TTI (sTTI)).

[0068] According to various techniques, physical channels may be multiplexed using carriers for communication. For example, physical control channels and physical data channels may be multiplexed using one or more of a time division multiplexing (TDM) technique, a frequency division multiplexing (FDM) technique, or a hybrid TDM-FDM technique to signal via a downlink carrier. A control region (e.g., a control resource set (CORESET)) of a physical control channel may be defined by a set of symbol periods and may extend across a system bandwidth of a carrier or a subset of that system bandwidth. One or more control regions (e.g., CORESETs) may be configured for a set of UEs 115. For example, one or more UEs in UE 115 may monitor or search a control region for control information according to one or more search space sets, and each search space set may include one or more control channel candidates in one or more aggregation levels arranged in a cascaded manner. The aggregation level of a control channel candidate may refer to the number of control channel resources (e.g., control channel elements (CCEs)) associated with coded information for a control information format having a given payload size. The search space sets may include a common search space set configured for transmitting control information to multiple UEs 115 , and a UE-specific search space set for transmitting control information to a specific UE 115 .

[0069] The network entity 105 may provide communication coverage via one or more cells (e.g., macro cells, small cells, hotspots, or other types of cells, or any combination thereof). The term "cell" may refer to a logical communication entity used to communicate with the network entity 105 (e.g., using a carrier), and may be associated with an identifier used to distinguish adjacent cells (e.g., a physical cell identifier (PCID), a virtual cell identifier (VCID), or other cell identifier). In some examples, a cell may also refer to a coverage area 110 or a portion of a coverage area 110 (e.g., a sector) on which a logical communication entity operates. Depending on various factors (such as the capabilities of the network entity 105), such cells may range from smaller areas (e.g., structures, subsets of structures) to larger areas. For example, a cell may be or include a building, a subset of a building, or an external space between or overlapping coverage areas 110, and the like.

[0070] A macro cell generally covers a relatively large geographic area (e.g., several kilometers in radius) and may allow unrestricted access to UEs 115 that have service subscriptions with a network provider that supports the macro cell. Small cells may be associated with lower power network entities 105 (e.g., lower power base stations 140) than macro cells, and small cells may operate using the same or different (e.g., licensed, unlicensed) frequency bands as macro cells. Small cells may provide unrestricted access to UEs 115 that have service subscriptions with a network provider, or may provide restricted access to UEs 115 associated with small cells (e.g., UEs 115 in a closed subscriber group (CSG), UEs 115 associated with users in a home or office). A network entity 105 may support one or more cells, and may also use one or more component carriers to support communications via one or more cells.

[0071] In some examples, a carrier may support multiple cells, and different cells may be configured according to different protocol types (e.g., MTC, narrowband IoT (NB-IoT), enhanced mobile broadband (eMBB)) that may provide access to different types of devices.

[0072] In some examples, the network entities 105 (e.g., base stations 140, RUs 170) may be mobile and thus provide communication coverage for mobile coverage areas 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, overlapping coverage areas 110 associated with different technologies may be supported by different network entities 105. The wireless communication system 100 may include, for example, a heterogeneous network in which different types of network entities 105 provide coverage for respective coverage areas 110 using the same or different radio access technologies.

[0073] The wireless communication system 100 may support synchronous operation or asynchronous operation. For synchronous operation, the network entities 105 (e.g., base stations 140) may have similar frame timing, and transmissions from different network entities 105 may be approximately aligned in time. For asynchronous operation, the network entities 105 may have different frame timing, and in some examples, transmissions from different network entities 105 may not be aligned in time. The techniques described herein may be used for synchronous operation or asynchronous operation.

[0074] Some UEs 115, such as MTC or IoT devices, may be low-cost or low-complexity devices and may allow automated communication between machines (e.g., via machine-to-machine (M2M) communication). M2M communication or MTC may refer to data communication technology that allows devices to communicate with each other or with a network entity 105 (e.g., base station 140) without human intervention. In some examples, M2M communication or MTC may include communication from devices that integrate sensors or meters to measure or capture information and relay such information to a central server or application that uses the information or presents the information to a person interacting with the application. Some UEs 115 may be designed to collect information or implement automated behavior of machines or other devices. Examples of applications for MTC devices include: smart metering, inventory monitoring, water level monitoring, equipment monitoring, health care monitoring, field survival monitoring, weather and geographic event monitoring, fleet management and tracking, remote security sensing, physical access control, and transaction-based commercial charging.

[0075] The wireless communication system 100 may be configured to support ultra-reliable communication or low-latency communication or various combinations thereof. For example, the wireless communication system 100 may be configured to support ultra-reliable low-latency communication (URLLC). UE 115 may be designed to support ultra-reliable, low-latency or critical functions. Ultra-reliable communication may include private communication or group communication, and may be 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" are used interchangeably herein.

[0076] In some examples, the UE 115 may be configured to support communication directly with other UEs 115 via a device-to-device (D2D) communication link 135 (e.g., according to a peer-to-peer (P2P), D2D, or sidelink protocol). In some examples, one or more UEs 115 in a group that are performing D2D communication may be within a coverage area 110 of a network entity 105 (e.g., a base station 140, a RU 170), which may support aspects of such D2D communication configured (e.g., scheduled) by the network entity 105. In some examples, one or more UEs 115 in such a group may be outside of the coverage area 110 of the network entity 105, or otherwise unable or not configured to receive transmissions from the network entity 105. In some examples, multiple groups of UEs 115 communicating via D2D communication 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, network entity 105 may facilitate scheduling of resources for D2D communications. In some other examples, D2D communications may be performed between UEs 115 without involving network entity 105.

[0077] In some systems, the D2D communication link 135 can be an example of a communication channel (such as a sidelink communication channel) between vehicles (e.g., UE 115). In some examples, the vehicles can communicate using vehicle-to-everything (V2X) communication, vehicle-to-vehicle (V2V) communication, or some combination of these items. The vehicle can signal information related to traffic conditions, signal scheduling, weather, safety, emergency situations, or any other information related to the V2X system. In some examples, the vehicles in the V2X system can communicate with roadside infrastructure (such as roadside units), or communicate with the network via one or more network nodes (e.g., network entity 105, base station 140, RU 170) using vehicle-to-network (V2N) communication, or both.

[0078] The core network 130 may provide user authentication, access authorization, tracking, Internet Protocol (IP) connectivity, and other access, routing or mobility functions. The core network 130 may be an evolved packet core (EPC) or a 5G core (5GC), which may include at least one control plane entity (e.g., a mobility management entity (MME), an access and mobility management function (AMF)) for managing access and mobility and at least one user plane entity (e.g., a serving gateway (S-GW), a packet data network (PDN) gateway (P-GW), or a user plane function (UPF)) for routing packets or interconnecting to an external network. The control plane entity may manage non-access stratum (NAS) functions, such as mobility, authentication, and bearer management of UE 115 served by a network entity 105 (e.g., a base station 140) associated with the core network 130. User IP packets may be delivered through the user plane entity, which may provide IP address allocation and other functions. The user plane entity may be connected to the IP service 150 of one or more network operators. IP services 150 may include access to the Internet, an intranet, an IP Multimedia Subsystem (IMS), or packet-switched streaming services.

[0079] The wireless communication system 100 may operate using one or more frequency bands that may be in the range of 300 megahertz (MHz) to 300 gigahertz (GHz). Generally speaking, the region from 300 MHz to 3 GHz is referred to as the ultra-high frequency (UHF) region or decimeter band because the wavelength ranges from about 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 these waves may be sufficient to penetrate structures so that macro cells provide services to UEs 115 located indoors. Communications using UHF waves may be associated with smaller antennas and shorter ranges (e.g., less than 100 kilometers) than communications using lower frequencies and longer waves in the high frequency (HF) or very high frequency (VHF) portions of the spectrum below 300 MHz.

[0080] The wireless communication system 100 may utilize licensed and unlicensed RF spectrum bands. For example, the wireless communication system 100 may employ license assisted access (LAA), LTE unlicensed (LTE-U) radio access technology, or NR technology using unlicensed bands (such as the 5 GHz industrial, scientific, and medical (ISM) band). When operating using unlicensed RF spectrum bands, devices such as network entity 105 and UE 115 may employ carrier sensing for conflict detection and avoidance. In some examples, operations using unlicensed bands may be based on carrier aggregation configuration in combination with component carriers operating using licensed bands (e.g., LAA). Operations using unlicensed spectrum may include downlink transmissions, uplink transmissions, P2P transmissions, or D2D transmissions, and the like.

[0081] The network entity 105 (e.g., base station 140, RU 170) or UE 115 may be equipped with multiple antennas that can be used to employ technologies such as transmit diversity, receive diversity, multiple-input multiple-output (MIMO) communications, or beamforming. The antennas of the network entity 105 or UE 115 may be located in one or more antenna arrays or antenna panels that can 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 the network entity 105 may be located at different geographical locations. The network entity 105 may include an antenna array having a set of antenna ports of multiple rows and columns that the network entity 105 can use to support beamforming for communications with the UE 115. Similarly, the UE 115 may include one or more antenna arrays that can support various MIMO or beamforming operations. Additionally or alternatively, the antenna panel may support RF beamforming for signals sent via the antenna ports.

[0082] The network entity 105 or UE 115 may use MIMO communication to utilize multipath signal propagation and improve spectral efficiency by sending or receiving multiple signals via different spatial layers. Such a technology may be referred to as spatial multiplexing. The multiple signals may be sent, for example, by a transmitting device via different antennas or different combinations of antennas. Similarly, the multiple signals may be received by a 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 for channel measurement and reporting. MIMO technology includes single-user MIMO (SU-MIMO) and multi-user MIMO (MU-MIMO), in which multiple spatial layers are sent to the same receiving device; in multi-user MIMO (MU-MIMO), multiple spatial layers are sent to multiple devices.

[0083] Beamforming (which may also be referred to as spatial filtering, 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 direct 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 signals conveyed via antenna elements of an antenna array so that some signals propagating along a particular orientation relative to the antenna array experience constructive interference, while other signals experience destructive interference. Adjustments to signals conveyed via antenna elements may include the transmitting device or the receiving device applying an amplitude offset, a phase offset, or both to signals carried via antenna elements associated with the device. Adjustments associated with each of these antenna elements may be defined by a set of beamforming weights associated with a particular orientation (e.g., relative to the antenna array of the transmitting device or the receiving device or relative to some other orientation).

[0084] The network entity 105 or the UE 115 may use beam sweeping techniques as part of a beamforming operation. For example, the network entity 105 (e.g., the base station 140, the RU 170) may use multiple antennas or antenna arrays (e.g., antenna panels) to perform beamforming operations for directional communication with the UE 115. Some signals (e.g., synchronization signals, reference signals, beam selection signals, or other control signals) may be sent multiple times by the network entity 105 along different directions. For example, the network entity 105 may send signals according to different sets of beamforming weights associated with different transmission directions. Transmission along different beam directions may be used to identify (e.g., by a transmitting device (such as the network entity 105), or by a receiving device (such as the UE 115)) the beam direction for later transmission or reception by the network entity 105.

[0085] Some signals, such as data signals associated with a particular receiving device, may be sent by a sending device (e.g., a sending network entity 105, a sending UE 115) along a single beam direction (e.g., a direction associated with a receiving device (such as a receiving network entity 105 or a receiving UE 115)). In some examples, a beam direction associated with transmission along a single beam direction may be determined based on signals sent along one or more beam directions. For example, UE 115 may receive one or more of the signals sent by network entity 105 along different directions, and may report to network entity 105 an indication of the signal received by UE 115 with the highest signal quality or other acceptable signal quality.

[0086] In some examples, transmission by a device (e.g., by network entity 105 or 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 network entity 105 to UE 115). UE 115 may report feedback indicating 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 subbands. Network entity 105 may send a reference signal (e.g., a cell-specific reference signal (CRS), a channel state information reference signal (CSI-RS)), which may be precoded or not precoded. 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 codebook, a linear combination codebook, a port selection codebook). Although these techniques are described with reference to signals sent along one or more directions by a network entity 105 (e.g., base station 140, RU 170), UE 115 may use similar techniques to send signals multiple times along different directions (e.g., to identify a beam direction for subsequent transmission or reception by UE 115), or to send signals along a single direction (e.g., to send data to a receiving device).

[0087] A receiving device (e.g., UE 115) may perform reception operations according to multiple reception configurations (e.g., directional listening) when receiving various signals (such as synchronization signals, reference signals, beam selection signals, or other control signals) from a receiving device (e.g., network entity 105). For example, the receiving device may perform reception according to multiple reception directions by: receiving via different antenna subarrays, processing received signals according to different antenna subarrays, receiving according to different reception beamforming weight sets (e.g., different directional listening weight sets) applied to signals received at multiple antenna elements of an antenna array, or processing received signals according to different reception 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 reception configurations or reception directions. In some examples, the receiving device may use a single reception configuration to receive along a single beam direction (e.g., when receiving a data signal). A 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 the highest signal strength, highest signal-to-noise ratio (SNR), or other acceptable signal quality based on listening according to multiple beam directions).

[0088] In some examples of the wireless communication system 100, one or more UEs 115 may share S-SSBs to support synchronization of the UEs 115 receiving these S-SSBs with the network entity 105. The transmission of these S-SSBs may be performed during a configured DRS window. For example, a first UE 115 within the coverage of a trusted synchronization source (e.g., the network entity 105) may receive synchronization information (e.g., SSBs) from the network entity 105. In order to benefit neighboring UEs 115 that are not within the coverage of the network entity 115 (e.g., the UE 115 did not receive the synchronization information), the first UE 115 may become an S-SSB sender (e.g., a first syncRef node) and send these S-SSBs containing the synchronization information from the network entity to other UEs 105.

[0089] A second UE 115, which may not be within the 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 send an S-SSB to a third UE 115 (becoming a second syncRef node). Thus, the synchronization information may continue to propagate through the system. However, UE 115 may have half-duplex limitations that inhibit efficient S-SSB transmission and reception. Additionally, due to LBT uncertainty in the system, the syncRef node may use additional opportunities to send these S-SSBs.

[0090] In order to support S-SSB transmission and reception in a wireless communication system 100 that may include a half-duplex UE 115, the techniques described herein support the configuration 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 continuous, non-overlapping, or time-combined (e.g., interleaved). In another example, a DRS window may be configured to include S-SSB transmission opportunities and S-SSB transmission reception opportunities (e.g., in an interleaved mode).

[0091] The techniques described herein also support configuration for a single DRS window that includes an S-SSB transmit opportunity, an S-SSB receive opportunity, and a set of additional S-SSB opportunities that may be used to transmit or receive. In some cases, to prevent timing issues, an S-SSB receiving UE 115 (e.g., a second syncRef node) may monitor the S-SSB from the first syncRef node before starting an S-SSB transmission, thereby forgoing a transmit opportunity until the S-SSB transmission may be accurate.

[0092] Figure 2 An example of a wireless communication system 200 that supports discovery reference signal window configuration for a sidelink according to one or more aspects of the present disclosure is illustrated. In some examples, the wireless communication system 200 may implement aspects of the wireless communication system 100, or may be implemented by aspects of the wireless communication system 100. For example, the wireless communication system 200 may include a UE 115-a and a network entity 105-a (which may be examples of corresponding devices as described herein).

[0093] In some implementations of the wireless communication system 200, the network entity 105-a may have a coverage area 205, which may be, for example, relative to Figure 1 100. UE 115-a may reside within coverage area 205, and network entity 105-a may communicate and share information with UE 115-a via communication link 125-a (e.g., access link). In some examples, network entity 105-a may send synchronization information (e.g., in an SSB message) to UE 115-a via communication link 125-a.

[0094] In some cases, UE 115-a may determine that a neighboring UE 115 is not receiving synchronization information and determine to send an S-SSB to a neighboring UE 115 (e.g., UE 115-b and UE 115-c). For example, UE 115-a may directly access timing and synchronization information from network entity 105-a (e.g., a synchronization source) and may therefore be considered a first syncRef node (a node with direct access to timing / synchronization information). In such an example, UE 115-a may determine to become an S-SSB sender (e.g., a first syncRef node) and send an S-SSB to support a neighboring UE (e.g., UE 115-b). In this way, synchronization information may be propagated through the wireless communication system 200.

[0095] According to some configurations, the number of S-SSB instances within an S-SSB period may be limited. In frequency 1 (FR1), when the subcarrier spacing is 15 kHz, the number of S-SSB instances or time slots may be 1 (e.g., K=1). In FR1 with 30 kHz subcarrier spacing, the number of S-SSB instances or time slots may be 1 or 2 (e.g., K=1, or K=2). However, since the UE 115 is to perform and clear the LBT procedure (e.g., LBT uncertainty) before sending the S-SSB, the S-SSB transmitting node may be configured with more opportunities to send the S-SSB. Therefore, if Figure 2 As illustrated, the UE 115 may be configured with a DRS window 215 starting at an S-SSB instance, which supports increasing S-SSB candidate positions for each S-SSB instance. A DRS window (e.g., DRS window 215) may be defined starting from an S-SSB instance, and the node may be configured to transmit S-SSBs during up to K S-SSB slots within the L candidate positions after clearing the LBT. For example, the node transmits during up to K S-SSB slots within the L S-SSB candidate positions 220 after clearing the LBT (e.g., K=4 in L=10 candidate positions; or K=8 in L=20 candidate positions).

[0096] Depending on the configuration of the DRS window 215, an S-SSB transmission 225 may be attempted at a first S-SSB candidate position 220, which is a nominal S-SSB candidate position 220. However, LBT may fail at the nominal S-SSB candidate position 220, which may prevent the transmission of the S-SSB. Therefore, the configuration of multiple S-SSB candidate positions 220 may support multiple attempts at S-SSB transmission 225. UE115-a may attempt LBT during the S-SSB candidate position 220 of the DRS window 215, and transmit the S-SSB based on clearing LBT. By introducing multiple S-SSB candidate positions 220 around each S-SSB instance (e.g., a DRS window starting from each S-SSB instance), LBT uncertainty in the system may be resolved by supporting multiple positions for performing an LBT procedure and multiple positions for S-SSB transmission. In the event that LBT is successful, the downstream node (e.g., UE 115-b) may rely on the first syncRef node (e.g., UE 115-a) as a timing reference for synchronization with the network entity 105-a.

[0097] In some examples of the present disclosure, UE 115-b may determine that UE 115-c does not have timing information sent from a first syncRef node (e.g., UE 115-a). For example, UE 115-b may detect that a third UE (e.g., UE 115-c) is a threshold distance away from UE 115-b and UE 115-a, such that UE 115-c is not in the coverage area 205 of network entity 105-a. The threshold distance may be a distance such that UE 115-c may not have a communication link with a trusted synchronization source (e.g., network entity 105-a) and may not have a communication link with the first syncRef node (e.g., UE 115-a), which may be used by UE 115-b as a timing reference. To prevent timing and synchronization problems, the second UE 115-b may attempt to become an S-SSB transmitter (e.g., a second syncRef node) based on a threshold or criterion (such as a distance threshold or a reference signal received power (RSRP) threshold). However, UE 115 - b may be limited by half-duplex constraints and thus may not be able to monitor the S-SSB message from the first syncRef node and send an S-SSB message to UE 115 - c in the same set of resources.

[0098] Due to the half-duplex nature of the nodes in the system (e.g., UE 115), at least two orthogonal S-SSB timing configurations may be defined. For example, a timing allocation (e.g., a first sl-SSB-TimeAllocation) is defined for receiving an S-SSB from a selected syncRef node (e.g., a first syncRef node or UE 115-a), and a second timing allocation (e.g., a second sl-SSB-TimeAllocation) is defined for sending an S-SSB. Each timing allocation (e.g., sl-SSB-TimeAllocation) may specify a time slot offset (e.g., sl-TimeOffsetSSB) from a period (e.g., a period of 160 ms), a time slot interval (e.g., sl-TimeInterval) between S-SSBs in the period (e.g., a period between S-SSB candidate positions 220), and the number of S-SSB transmission instances within a period (e.g., sl-NumSSB-WithinPeriod). However, such a configuration may result in LBT uncertainty because there is one S-SSB candidate position for an S-SSB transmission by a particular node.

[0099] As described herein, to limit or reduce LBT uncertainty, multiple S-SSB candidate time slots around each candidate instance are introduced. In addition, to address half-duplex operation of the syncRef node, the techniques described herein support configurations for multiple S-SSB transmit opportunities and multiple S-SSB receive opportunities in one or more DRS windows (such as DRS window 215). In addition, 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. With respect to Figure 3A , Figure 3B and Figure 4 These DRS window configurations are described in further detail.

[0100] Figure 3A Examples of resource diagrams 300 and 301 supporting discovery reference signal window configuration for a sidelink according to one or more aspects of the present disclosure are illustrated. In some examples, resource diagrams 300 and 301 may be implemented by aspects of wireless communication systems 100 and 200. For example, resource diagrams 300 and 301 may be implemented by UE 115 and network entity 105 (which may be examples of corresponding devices as described herein).

[0101] Aspects of the present disclosure may support various configurations of one or more DRS windows in a network. In some examples, at least two DRS windows may allow allocation of two sets of S-SSB time resources (e.g., one set for S-SSB transmission and one set for S-SSB candidate monitoring). A set of S-SSB opportunities for monitoring S-SSB transmissions from a syncRef node (e.g., an S-SSB transmitter) may be associated with a receive DRS window (e.g., receive DRS window 310 or receive DRS window 330), and a set of S-SSB opportunities for S-SSB transmissions with multiple candidate positions may be associated with a transmit DRS window (e.g., transmit DRS window 315 and transmit DRS window 335). In some examples, the configuration of a DRS window (e.g., a receive DRS window or a transmit DRS window) may include the number of S-SSB opportunities and the time slot intervals between S-SSB opportunities. In a defined timing allocation configuration (e.g., sl-SSB-TimeAllocation), the S-SSB candidate time slots (e.g., opportunities) may be defined to include the S-SSB instance and after the S-SSB instance. In some cases, if it is determined that the S-SSB candidate time slots should be consecutive, the time slot interval between the S-SSB candidate time slots may be set to 0.

[0102] According to aspects of the present disclosure, resource diagram 300 illustrates a DRS configuration including two DRS windows, wherein the receive DRS window 310 and the transmit DRS window 315 do not overlap. For example, the S-SSB candidate slot intervals for both the receive DRS window 310 and the transmit DRS window 315 may be set to 0 to allow the S-SSB candidate slots to be continuous. In some examples, the slot intervals may be set to 0 to shorten the length of the DRS window (e.g., the receive DRS window 310 and / or the transmit DRS window 315). Thus, the receiver may not monitor the S-SSB candidates for an extended amount of time, and may minimize transmit and receive switching. It should be understood that the SSB timing of one or more of the receive DRS window 310 and the transmit DRS window 315 may be discontinuous (e.g., positioned with an intermediate slot interval).

[0103] As illustrated in resource diagram 300, transmit DRS window 315 may start after receive DRS window 310 is completed. Thus, the UE may wait until the UE has received at least a portion of the S-SSB message in receive DRS window 310 before sending the S-SSB message in transmit DRS window 315.

[0104] The receive DRS window 310 includes multiple S-SSB receive opportunities 320 for receiving S-SSB messages. In the presence of LBT uncertainty at the transmitting node, the configuration of multiple receive opportunities can support more opportunities for receiving S-SSB messages. Additionally, the transmit DRS window 315 may include multiple S-SSB transmit opportunities 325 for sending S-SSB messages. In the presence of LBT uncertainty, including multiple S-SSB transmit opportunities can support more opportunities for clearing LBT and sending S-SSB messages. In some cases, the configuration of the transmit DRS window 315 can support sending S-SSB bursts in a set of S-SSB transmit opportunities (e.g., multiple opportunities).

[0105] Resource diagram 300 may be used with a small number of S-SSB receive opportunities 320 and S-SSB transmit opportunities 325. Since transmit DRS window 315 may wait until receive DRS window 310 is completed, a large number of S-SSB receive opportunities 320 and S-SSB transmit opportunities 325 may cause large delays in the system. Thus, resource diagram 300 provides support for basic reception and transmission between two UEs 115 with a small number of S-SSB candidate locations. In addition, resource diagram 300 may support reduced UE complexity because the UE may not continuously or periodically switch between S-SSB transmit opportunities and S-SSB receive opportunities.

[0106] Resource diagram 301 illustrates a DRS window configuration with two time-combined DRS windows (e.g., an interleaved pattern). The DRS configuration may include a receive DRS window 330 with multiple S-SSB receive opportunities 340 and a transmit DRS window 335 with multiple S-SSB transmit opportunities 345. As illustrated, the S-SSB transmit opportunities 345 of the transmit DRS window 335 may not overlap with the S-SSB receive opportunities 340 of the receive DRS window 330.

[0107] The transmit DRS window 335 of the resource diagram 301 may start during the receive DRS window 330. In such a specific implementation, the slot interval 350 (e.g., the spacing in the time domain) may be set to be greater than 0. In some cases, the slot interval 350 may be set to be equal to the length of one S-SSB receive opportunity 340 or S-SSB transmit opportunity 345. For example, during the period of the candidate slot interval 350, the syncRef node may switch between the receive DRS window 330 and the transmit DRS window 335. Therefore, the syncRef node may not wait until all S-SSB receive opportunities in the S-SSB receive opportunities 340 from the syncRef UE are monitored before starting the transmit DRS window 335.

[0108] The resource diagram 301 may be implemented using a large number of S-SSB receive opportunities 340 and S-SSB transmit opportunities 345. The syncRef node is enabled to switch between the receive DRS window 330 and the transmit DRS window 335, thereby supporting the syncRef node to send an S-SSB message after receiving the S-SSB message. However, according to the resource diagram 301, the syncRef node may switch back and forth between the receive DRS window 330 for monitoring S-SSB messages and the transmit DRS window 335 for sending the received S-SSB message, which may result in increased UE complexity. In some examples, the LBT procedure may fail at an S-SSB transmit opportunity 345 in the transmit DRS window 335, and may wait until the next receive DRS window slot (e.g., an opportunity in the receive DRS window 330) to attempt to send at another S-SSB transmit opportunity 345, which may result in a delay in the communication of synchronization information.

[0109] like Figure 3A As illustrated, the receive DRS window 310 and the transmit DRS of resource diagram 300 and the receive DRS window 330 and the transmit DRS window 335 of resource diagram 301 may be located in different frequency resources. In some examples, the different frequency resources are orthogonal. It should be understood that the corresponding receive DRS window and transmit DRS window may be located in the same or overlapping frequency resources. In addition, Figure 3AThe S-SSB transmission opportunity and S-SSB reception opportunity of may correspond to a time slot (e.g., the S-SSB reception opportunity 320 is a corresponding time slot), or may be located in respective parts of a corresponding time slot. It should be understood that the S-SSB transmission opportunity and the S-SSB reception opportunity may correspond to other types of transmission time intervals.

[0110] However, the configurations illustrated in resource diagrams 300 and 301 may result in greater overhead in the network. In some cases, multiple S-SSB candidate slots in each DRS window may be excluded from the data resource pool. Therefore, the configuration of multiple orthogonal DRS windows may cause the S-SSB candidate overhead to increase accordingly with the number of DRS windows. For example, for S-SSB candidate slots within a DRS window, the syncRef node may send up to K S-SSB slots (e.g., K may be equal to 1) at the earliest slot (e.g., S-SSB candidate opportunity) that clears the LBT procedure. In some cases, if the LBT is cleared in advance, the resources of the remaining S-SSB transmission opportunities may not be used.

[0111] Figure 3B An example of a resource diagram 302 supporting a discovery reference signal window configuration for a sidelink according to one or more aspects of the present disclosure is illustrated. In some examples, the resource diagram 300 may be implemented by aspects of wireless communication systems 100 and 200. For example, the resource diagram 302 may be implemented by UE 115 and network entity 105 (which may be examples of corresponding devices as described herein).

[0112] In some examples, a DRS window 355 may be configured, and the even and odd indexed time slots (e.g., opportunities) within the DRS window 355 may be associated with two orthogonal S-SSB resources for reception and transmission, respectively. For example, a single DRS window 355 may be a DRS window for both reception and transmission of S-SSB messages (e.g., a receive / transmit DRS window). The DRS window 355 may include multiple S-SSB reception opportunities (e.g., S-SSB reception opportunities 360) and multiple S-SSB transmission opportunities (e.g., S-SSB transmission opportunities 365). In some examples, the syncRef node may monitor the S-SSB messages in the even indexed time slots (e.g., S-SSB reception opportunities). Therefore, in the odd indexed time slots (e.g., S-SSB transmission opportunities), the syncRef node may attempt to clear the LBT procedure and send the S-SSB message.

[0113] In some cases, the syncRef node may wait until an S-SSB message is received 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 sending the S-SSB message in the DRS window 355. Thus, in one example, if the UE does not receive an S-SSB during the S-SSB reception opportunity 360, the UE may not use the S-SSB transmission opportunity 365 to perform an LBT procedure and / or send an S-SSB. Thereafter, if the UE receives an S-SSB during a subsequent S-SSB reception opportunity, the UE may perform LBT and / or send an S-SSB during an S-SSB transmission opportunity subsequent to the S-SSB reception opportunity in which the S-SSB was received. Figure 3B The S-SSB transmission opportunities and S-SSB transmission opportunities may be located in the same or overlapping frequency resources, or in different and / or orthogonal frequency resources. Figure 3A As stated, Figure 3B The S-SSB transmission opportunities and S-SSB reception opportunities of may correspond to time slots (e.g., S-SSB reception opportunities 360 are time slots), or may be located in portions of time slots. It should be understood that the S-SSB transmission opportunities and S-SSB reception opportunities may correspond to other types of transmission time intervals.

[0114] Figure 4 An example of a resource diagram 400 supporting a discovery reference signal window configuration for a sidelink according to one or more aspects of the present disclosure is illustrated. In some examples, the resource diagram 400 may be implemented by aspects of wireless communication systems 100 and 200. For example, the resource diagram 400 may be implemented by UE 115 and network entity 105 (which may be examples of corresponding devices as described herein).

[0115] According to the present disclosure, some implementations may have a single DRS window configuration for both reception and transmission (e.g., a receive / transmit DRS window 405). In some examples, the receive / transmit DRS window 405 may include a first S-SSB opportunity 410, a second S-SSB opportunity 415, and an additional S-SSB transmission opportunity set 420. In some cases, an additional S-SSB transmission opportunity set 420 is included to provide additional LBT and S-SSB transmission or reception opportunities for the receive / transmit DRS window 405. For example, the additional S-SSB transmission opportunity set 420 may be used dynamically (e.g., the opportunity may be used for S-SSB reception or transmission). In some cases, the first S-SSB opportunity 410 may be reserved as a transmission S-SSB opportunity to send an S-SSB message from a syncRef node (e.g., a first syncRef node that relies on timing and / or synchronization information via an S-SSB message) to a second syncRef node. The second S-SSB opportunity may be reserved for sending an S-SSB message from the second syncRef node to a neighboring UE 115. In some implementations, the first syncRef node will not transmit during the second S-SSB opportunity, and will wait until after the second S-SSB opportunity before attempting to transmit again (e.g., performing another LBT procedure). Therefore, the second syncRef node may not be allowed to transmit during the first S-SSB opportunity. Both the first syncRef node and the second syncRef node may transmit during the opportunities of the additional S-SSB transmission opportunity set 420 according to various conditions, situations, or implementations.

[0116] In some other implementations, the resource diagram 400 includes both a receive DRS window and a transmit DRS window. Thus, the additional S-SSB transmit opportunity set 420 may overlap between the receive DRS window and the transmit DRS window. The first S-SSB opportunity 410 may be in the receive DRS window and used to receive an S-SSB message from the first syncRef node, and the second S-SSB opportunity 415 may be in the transmit DRS window and used to send an S-SSB message by the second syncRef node.

[0117] In some examples, both the first syncRef node and the second syncRef node may transmit S-SSB messages in the additional S-SSB transmission opportunity set 420. However, half-duplex limitations may cause synchronization issues at the UE. For example, the first syncRef node and the second syncRef node may transmit during the same S-SSB opportunity in the additional S-SSB transmission opportunity set 420. Therefore, due to overlapping transmissions and half-duplex limitations, the second syncRef node may not receive timing and synchronization information (via S-SSB messages) from the first syncRef node.

[0118] Therefore, considering the half-duplex limitation, the second syncRef node may determine that the synchronization accuracy (e.g., timing and / or frequency accuracy) is below a certain threshold (e.g., synchronization accuracy threshold), and thus synchronize with the first syncRef node based on the received S-SSB. The second syncRef node may monitor the S-SSB message from the first syncRef node, and the second syncRef node does not start S-SSB transmission (after clearing LBT) until the S-SSB message is received and detected in the receive / transmit DRS window 405. Therefore, the second syncRef node may abandon any possible transmission opportunity in the receive / transmit DRS window 405 until the S-SSB message is received, thereby improving the synchronization accuracy in the wireless communication system.

[0119] In some examples, the second syncRef node may not receive an S-SSB message from the first syncRef node until the first S-SSB opportunity 425 in the additional S-SSB transmission opportunity set 420. For example, due to LBT failure, an S-SSB message may not be sent from the first syncRef node to the second syncRef node during the first S-SSB opportunity 410. Therefore, the second syncRef node may give up the transmission opportunity during the second S-SSB opportunity 415 and wait until the S-SSB transmission opportunity in the additional S-SSB transmission opportunity set 420. The second syncRef node may receive an S-SSB message from the first syncRef node during the first S-SSB opportunity 425 in the additional S-SSB transmission opportunity set 420 in the receive / transmit DRS window 405. During the second S-SSB opportunity 430 in the additional S-SSB transmission opportunity set 420, the second syncRef node may send an S-SSB message (e.g., based on clearing LBT). Therefore, the second syncRef node may use the additional S-SSB transmission opportunity set 420 to ensure that the second syncRef node receives the S-SSB message from the first syncRef node in order to support improved synchronization accuracy in the wireless communication system.

[0120] Figure 5 An example of a process flow 500 for supporting a discovery reference window configuration for a side link according to various aspects of the present disclosure is illustrated. The process flow 500 may implement various aspects of the wireless communication systems 100 and 200, or may be implemented by various aspects of the wireless communication systems 100 and 200. For example, the process flow 500 may illustrate operations between UE 115-d, UE 115-e, UE 115-f, and 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 UE 115-d, UE 115-e, UE 115-f, and network entity 105-b may be sent in an order different from the example order shown, or the operations performed may be performed in a different order or at a different time. Some operations may also be omitted from the process flow 500, and other operations may be added to the process flow 500.

[0121] At 505-a, network entity 105-b may send a configuration for one or more DRS windows. UE 115-d may receive signaling including the configuration for the one or more DRS windows from network entity 105-b. At 505-b, UE 115-e may receive signaling indicating the configuration for the one or more DRS windows. According to the configuration, the configuration of the one or more DRS windows may include two or more SSB reception opportunities and two or more SSB transmission opportunities. In some cases, UE 115-e may be considered to be a first UE and UE 115-d may be considered to be a second UE. At 505-b, the signaling indicating the configuration may be sidelink control signaling (e.g., sidelink control information (SCI)). In some examples, UE 115-e may relay the configuration for the one or more DRS windows to UE 115-f using control signaling.

[0122] In some examples, UE 115-e receiving the signaling indicating the configuration includes: receiving signaling indicating a receive DRS window. The receive DRS window may include two or more SSB receive opportunities. Additionally, receiving the signaling indicating the configuration at UE 115-e may also include: receiving signaling indicating a send DRS window. The send DRS window may include two or more SSB send opportunities. In some cases, the resources of the receive DRS window and the resources of the send DRS window may not overlap in the time domain. In some other cases, the resources of the receive DRS window and the resources of the send DRS window may at least partially overlap in the time domain. In such cases, at least one of the SSB receive opportunities may be located in the time domain (e.g., in an interleaved mode) at least between at least two of the SSB send opportunities. In some cases, the resources of the receive DRS window and the resources of the send DRS window may not overlap in the frequency domain (e.g., located in different frequency resources, which may be orthogonal).

[0123] In some other examples, UE 115-e receiving the signaling indicating the configuration includes: receiving signaling indicating a DRS window (e.g., a single DRS window). For example, the DRS window may include the two or more SSB receive opportunities and the two or more SSB transmit opportunities. In some cases, at least one of the SSB receive opportunities may be positioned in the time domain (e.g., in an interleaved pattern) between at least two of the SSB transmit opportunities.

[0124] In some implementations, the UE 115-e receiving the signaling indicating the configuration includes receiving an indication of a first number of the two or more SSB transmission opportunities. Additionally, the configuration may include a second number of the two or more SSB reception opportunities, or both the first number and the second number.

[0125] In some examples, UE 115-e receiving the signaling indicating the configuration includes: receiving an indication of the spacing between the first SSB opportunity and the second SSB opportunity of the one or more DRS windows in the time domain. For example, the indication of the spacing between the first SSB opportunity and the second SSB opportunity may indicate a number of time slots. In some examples, the indicated number of time slots may be 0, so that the first SSB opportunity and the second SSB opportunity are adjacent to each other. In some cases, each SSB receive opportunity of the two or more SSB receive opportunities and each transmit opportunity of the two or more transmit opportunities may correspond to a corresponding time slot of the one or more DRS windows.

[0126] At 510, UE 115-e may monitor reception of an S-SSB message from UE 115-d during the two or more SSB reception opportunities of the one or more DRS windows based at least in part on the configuration.

[0127] At 515, UE 115-e may receive a first S-SSB message from UE 115-d during the two or more SSB reception opportunities of the one or more DRS windows. In some examples, UE 115-e may receive the first S-SSB message from UE 115-d based at least on the monitoring at 510. In some cases, the first S-SSB message may include synchronization or timing information from UE 115-d. In such cases, UE 115-e may not be in the coverage area of ​​network entity 105-b, and UE 115-d may be in the coverage area of ​​network entity 105-b. In such examples, UE 115-d may send the first S-SSB message to UE 115-e. The first S-SSB message may include synchronization or timing information from network entity 105-b.

[0128] At 520, in some implementations, the UE 115-e may determine that the synchronization accuracy of the UE 115-e satisfies a synchronization accuracy threshold. The synchronization accuracy may include a timing or frequency accuracy of a wireless system. The wireless system may be an example of the wireless communication system 100 or the wireless communication system 200.

[0129] At 525, in some cases, UE 115-e may perform an LBT procedure during the one or more DRS windows. For example, UE 115-e may send a second S-SSB message in response to clearing the LBT procedure. In some examples, in the event that the LBT procedure fails, the one or more DRS windows may include two or more SSB transmission opportunities.

[0130] At 530, UE 115-e may send the second S-SSB message to UE 115-f based at least on the configuration. UE 115-e may send the second S-SSB message to UE 115-f during at least one SSB transmission opportunity of the two or more SSB transmission opportunities of the one or more DRS windows. In some examples, UE 115-e may send the second S-SSB message to UE 115-f during at least one SSB transmission opportunity in response to receiving the first S-SSB message from UE 115-d during at least one SSB reception opportunity of the two or more SSB reception opportunities. In some examples, UE 115-e may send the second S-SSB message to UE 115-f during at least one SSB transmission opportunity in response to determining that the synchronization accuracy of UE 115-e satisfies the synchronization accuracy threshold and / or in response to clearing the LBT procedure.

[0131] Figure 6 An example of a process flow 600 for supporting a discovery reference window configuration for a side link according to various aspects of the present disclosure is illustrated. The process flow 600 may implement various aspects of the wireless communication systems 100 and 200, or may be implemented by various aspects of the wireless communication systems 100 and 200. For example, the process flow 600 may illustrate operations between UE 115-g, UE 115-h, UE 115-i, and 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 UE 115-g, UE 115-h, UE 115-i, and network entity 105-c may be sent in an order different from the example order shown, or the operations performed may be performed in a different order or at a different time. Some operations may also be omitted from the process flow 600, and other operations may be added to the process flow 600.

[0132] At 605-a, the network entity 105-c may send signaling to the UE 115-g indicating a configuration for one or more DRS windows. The configuration for each of the one or more DRS windows may include a first SSB opportunity for sending a first S-SSB message and a second SSB opportunity for sending a second S-SSB message. Additionally, the configuration for the one or more DRS windows may include an additional SSB transmission opportunity set.

[0133] At 605-b, UE 115-g may send the signaling indicating the configuration for the one or more DRS windows to UE 115-h. The configuration for each of the one or more DRS windows may include the first SSB opportunity for sending the first S-SSB message and the second SSB opportunity for sending the second S-SSB message. Additionally, the configuration of the one or more DRS windows may include the set of additional SSB transmission opportunities.

[0134] In addition, at 605-b, UE 115-h may receive the signaling indicating the configuration for the one or more DRS windows from UE 115-g. In some examples, UE 115-h may relay the configuration of the one or more DRS windows to UE 115-i. The configuration of each DRS window in the one or more DRS windows may include the first SSB opportunity for sending the first S-SSB message and the second SSB opportunity for sending the second S-SSB message. The first SSB opportunity may be used by UE 115-g to send the first S-SSB, and by UE 115-h to monitor UE 115-g's sending of the first S-SSB message. The second SSB opportunity may be used by UE 115-h to send the second S-SSB message, and by UE 115-i to monitor UE 115-h's sending of the second S-SSB message. In some cases, UE 115-h may be considered to be a first UE, and UE 115-g may be considered to be a second UE. Additionally, the configuration of the one or more DRS windows may include the set of additional SSB transmission opportunities. The set of additional SSB transmission opportunities may be configured for transmitting S-SSBs by any UE 115 in the set of UEs 115. The set of UEs 115 may include UE 115-g and UE 115-h. In some examples, each of the first SSB opportunity, the second SSB opportunity, and the additional SSB transmission opportunity may correspond to a respective time slot of the one or more DRS windows.

[0135] At 610, UE 115-h may monitor the transmission of the first S-SSB message from UE 115-g during the first SSB opportunity of the one or more DRS windows based at least on the configuration of the one or more DRS windows received at 605-b.

[0136] At 615, UE 115-h may receive the first S-SSB message from UE 115-g during the first SSB opportunity of the one or more DRS windows.

[0137] At 620, UE 115-h may attempt to send the second S-SSB during the second SSB opportunity of the one or more DRS windows. In some examples, whether to send the second S-SSB message during the SSB opportunity is based on whether the first S-SSB message is received during the first SSB opportunity, whether the synchronization accuracy of UE 115-h is greater than a synchronization accuracy threshold, and / or whether UE 115-h successfully performs an LBT procedure during the second SSB opportunity.

[0138] At 625, in some examples, UE 115-h may monitor the transmission of the first S-SSB message from UE 115-g during an SSB opportunity in the set of additional SSB transmission opportunities. UE 115-h may monitor the transmission of the first S-SSB message from UE 115-g during the SSB opportunity in the set of additional SSB transmission opportunities based at least on a failure to receive or decode the first message during the first SSB opportunity (e.g., determining that the first S-SSB message is not present). For example, an LBT procedure performed by UE 115-g may fail during the first SSB opportunity, and therefore UE 115-g may refrain from transmitting the S-SSB during the first SSB opportunity. Additionally, since the synchronization accuracy threshold is determined to be not met, UE 115-h may monitor the first S-SSB message during the set of additional SSB transmission opportunities.

[0139] At 630, UE 115-h may send the first S-SSB message during the first additional SSB transmission opportunity in the additional SSB transmission opportunity set based on UE 115-g sending the first S-SSB message during the first additional SSB transmission opportunity in the additional SSB transmission opportunity set.

[0140] At 640, UE 115-a may send the second S-SSB message during the additional SSB transmission opportunity set. Whether UE 115-h sends the second S-SSB message during the additional SSB transmission opportunity set may be based at least on whether UE 115-h sends the second S-SSB message during the second SSB opportunity. In some cases, UE 115-h may not send the second S-SSB message during the second SSB opportunity due to failure of the LBT procedure performed by UE 115-h. In some other cases, UE 115-h may send the second S-SSB message to UE 115-i during the second additional SSB transmission opportunity in the additional SSB transmission opportunity set based at least on receiving the first S-SSB message during the first additional SSB transmission opportunity. Additionally, UE 115-h may send the second S-SSB message during the SSB transmission opportunity in the additional transmission opportunity set based on success of the LBT procedure performed during the SSB transmission opportunity in the additional transmission opportunity set.

[0141] Figure 7 A block diagram 700 of a device 705 supporting discovery reference signal window configuration for a sidelink according to one or more aspects of the present disclosure is shown. 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 communication manager 720. The device 705 may also include a processor. Each of these components may communicate with each other (e.g., via one or more buses).

[0142] The receiver 710 may provide 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 configurations for sidelinks). The information may be delivered to other components of the device 705. The receiver 710 may utilize a single antenna or a collection of multiple antennas.

[0143] The transmitter 715 may provide 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 the discovery reference signal window configuration for the sidelink). In some examples, the transmitter 715 may be co-located with the receiver 710 in a transceiver module. The transmitter 715 may utilize a single antenna or a collection of multiple antennas.

[0144] The communication manager 720, the receiver 710, the transmitter 715, or various combinations thereof, or various components thereof, may be examples of means for performing various aspects of the discovery reference signal window configuration for the sidelink as described herein. For example, the communication manager 720, the receiver 710, the transmitter 715, or various combinations thereof, or components thereof, may support methods for performing one or more of the functions described herein.

[0145] In some examples, the communication manager 720, the receiver 710, the transmitter 715, or various combinations or components thereof may be implemented in hardware (e.g., in a communication management circuit system). 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 components, discrete hardware components, or any combination thereof configured as or otherwise supporting components for performing the functions described in the present disclosure. In some examples, a processor and a memory coupled to the processor may be configured to perform one or more of the functions described herein (e.g., by executing instructions stored in the memory by the processor).

[0146] Additionally or alternatively, in some examples, the communication manager 720, the receiver 710, the transmitter 715, or various combinations or components thereof may be implemented in code executed by a processor (e.g., as communication management software or firmware). If implemented in code executed by a processor, the functionality of the communication manager 720, the receiver 710, the transmitter 715, or various combinations or components thereof may be performed by a general purpose processor (e.g., configured as or otherwise supporting means for performing the functionality described in the present disclosure), a DSP, a CPU, an ASIC, an FPGA, a microcontroller, or any combination of these or other programmable logic devices.

[0147] In some examples, the communication manager 720 can be configured to perform various operations (e.g., receive, obtain, monitor, output, send) using or otherwise cooperating with the receiver 710, the transmitter 715, or both. For example, the communication manager 720 can receive information from the receiver 710, transmit information to the transmitter 715, or integrate with the receiver 710, the transmitter 715, or both to obtain information, output information, or perform various other operations as described herein.

[0148] Additionally or alternatively, according to the examples disclosed herein, the communication manager 720 may support wireless communication at the first UE. For example, the communication manager 720 may be configured as or otherwise support a component for receiving signaling indicating a configuration for one or more discovery reference signal windows, according to which the one or more discovery reference signal windows include two or more synchronization signal block reception opportunities and two or more synchronization signal block transmission opportunities. The communication manager 720 may be configured as or otherwise support a component for monitoring the reception of a first side link synchronization signal block message from a second UE during the two or more synchronization signal block reception opportunities of the one or more discovery reference signal windows based on the configuration. The communication manager 720 may be configured as or otherwise support a component for sending a second side link synchronization signal block message to a third UE during at least one of the two or more synchronization signal block transmission opportunities of the one or more discovery reference signal windows based on the configuration.

[0149] Additionally or alternatively, according to the examples disclosed herein, the communication manager 720 may support wireless communication at the first UE. For example, the communication manager 720 may be configured as or otherwise support a component for receiving signaling indicating a configuration for one or more discovery reference signal windows, each of the one or more discovery reference signal windows including a first synchronization signal block opportunity, a second synchronization signal block opportunity, and an additional synchronization signal block transmission opportunity set, the first synchronization signal block opportunity being used for the second UE to send a first side link synchronization signal block message, the second synchronization signal block opportunity being used for the first UE to send a second side link synchronization signal block message, and the additional synchronization signal block transmission opportunity set being configured for use by any UE in the UE set including the first UE and the second UE. The communication manager 720 may be configured as or otherwise support a component for monitoring the second UE's transmission of the first side link synchronization signal block message during the first synchronization signal block opportunity of the one or more discovery reference signal windows based on the configuration. The communication manager 720 may be configured as or otherwise support a component for attempting to send the second side link synchronization signal block message during the second synchronization signal block opportunity of the one or more discovery reference signal windows based on the configuration. In some examples, the communication manager 720 may be configured as or otherwise support a component for the following operations: the first UE monitors the second UE's sending of the first side link synchronization signal block message during the additional synchronization signal block sending opportunity set based on whether the first UE receives the first side link synchronization signal block message during the first synchronization signal block opportunity, and the first UE sends the second side link synchronization signal block message during the additional synchronization signal block sending opportunity set based on whether the first UE sends the second side link synchronization signal block message during the second synchronization signal block opportunity.

[0150] By including or configuring the communication manager 720 according to the examples described herein, the device 705 (e.g., a processor controlling the receiver 710, the transmitter 715, the communication manager 720, or a combination thereof or otherwise coupled thereto) can support techniques for reducing processing due to improved synchronization with the network. For example, by performing the S-SSB procedure according to the DRS window configuration described herein, synchronization information can be more efficiently notified to each UE, resulting in reduced processing overhead due to lack of or reduced synchronization with the network.

[0151] Figure 8A block diagram 800 of a device 805 supporting a discovery reference signal window configuration for a sidelink according to one or more aspects of the present disclosure is shown. The device 805 may be an example of aspects of the device 705 or UE 115 as described herein. The device 805 may include a receiver 810, a transmitter 815, and a communication manager 820. The device 805 may also include a processor. Each of these components may communicate with each other (e.g., via one or more buses).

[0152] The receiver 810 may provide 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 configurations for sidelinks). The information may be delivered to other components of the device 805. The receiver 810 may utilize a single antenna or a collection of multiple antennas.

[0153] The transmitter 815 may provide 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 the discovery reference signal window configuration for the sidelink). In some examples, the transmitter 815 may be co-located with the receiver 810 in a transceiver module. The transmitter 815 may utilize a single antenna or a collection of multiple antennas.

[0154] The device 805 or its various components may be examples of components for performing various aspects of the discovery reference signal window configuration for the side link as described herein. For example, the communication manager 820 may include a configuration signaling interface 825, an SSB monitoring component 830, an SSB transmission component 835, or any combination thereof. The communication manager 820 may be an example of various aspects of the communication manager 720 as described herein. In some examples, the communication manager 820 or its various components may be configured to use or otherwise cooperate with the receiver 810, the transmitter 815, or both to perform various operations (e.g., receive, obtain, monitor, output, send). For example, the communication manager 820 may receive information from the receiver 810, transmit information to the transmitter 815, or integrate with the receiver 810, the transmitter 815, or both to obtain information, output information, or perform various other operations as described herein.

[0155] According to the examples disclosed herein, the communication manager 820 may support wireless communication at the first UE. The configuration signaling interface 825 may be configured as or otherwise support a component for receiving signaling indicating a configuration for one or more discovery reference signal windows, according to which the one or more discovery reference signal windows include two or more synchronization signal block reception opportunities and two or more synchronization signal block transmission opportunities. The SSB monitoring component 830 may be configured as or otherwise support a component for monitoring the reception of a first side link synchronization signal block message from a second UE during the two or more synchronization signal block reception opportunities of the one or more discovery reference signal windows based on the configuration. The SSB transmission component 835 may be configured as or otherwise support a component for transmitting a second side link synchronization signal block message to a third UE during at least one of the two or more synchronization signal block transmission opportunities of the one or more discovery reference signal windows based on the configuration.

[0156] Additionally or alternatively, according to an example as disclosed herein, the communication manager 820 may support wireless communication at the first UE. The configuration signaling interface 825 may be configured as or otherwise support a component for receiving signaling indicating a configuration for one or more discovery reference signal windows, each of the one or more discovery reference signal windows including a first synchronization signal block opportunity, a second synchronization signal block opportunity, and an additional synchronization signal block transmission opportunity set, the first synchronization signal block opportunity being used for the second UE to send a first side link synchronization signal block message, the second synchronization signal block opportunity being used for the first UE to send a second side link synchronization signal block message, and the additional synchronization signal block transmission opportunity set being configured for use by any UE in the UE set including the first UE and the second UE. The SSB monitoring component 830 may be configured as or otherwise support a component for monitoring the second UE's transmission of the first side link synchronization signal block message during the first synchronization signal block opportunity of the one or more discovery reference signal windows based on the configuration. The SSB transmission component 835 may be configured as or otherwise support a component for attempting to transmit the second side link synchronization signal block message during the second synchronization signal block opportunity of the one or more discovery reference signal windows based on the configuration. In some examples, the SSB reception component 840 may be configured as or otherwise support a component for the first UE to monitor the second UE's transmission of the first side link synchronization signal block message during the additional synchronization signal block transmission opportunity set based on whether the first UE received the first side link synchronization signal block message during the first synchronization signal block opportunity, and the additional opportunity component 845 may be configured as or otherwise support a component for the first UE to transmit the second side link synchronization signal block message during the additional synchronization signal block transmission opportunity set based on whether the first UE transmitted the second side link synchronization signal block message during the second synchronization signal block opportunity.

[0157] Fig. 9A block diagram 900 of a communication manager 920 supporting a discovery reference signal window configuration for a side link according to one or more aspects of the present disclosure is shown. The communication manager 920 may be an example of various aspects of the communication manager 720, the communication manager 820, or both as described herein. The communication manager 920 or its various components may be examples of components for performing various aspects of the discovery reference signal window configuration for the side link as described herein. For example, the communication manager 920 may include a configuration signaling interface 925, an SSB monitoring component 930, an SSB transmission component 935, an SSB opportunity configuration interface 940, an additional opportunity component 945, an SSB non-existence component 950, a synchronization accuracy component 955, an SSB reception component 960, an LBT component 965, or any combination thereof. Each of these components may communicate directly or indirectly with each other (e.g., via one or more buses).

[0158] Additionally or alternatively, according to examples as disclosed herein, the communication manager 920 may support wireless communication at the first UE. The configuration signaling interface 925 may be configured as or otherwise support a component for receiving signaling indicating a configuration for one or more discovery reference signal windows, according to which the one or more discovery reference signal windows include two or more synchronization signal block reception opportunities and two or more synchronization signal block transmission opportunities. The SSB monitoring component 930 may be configured as or otherwise support a component for monitoring the reception of a first side link synchronization signal block message from a second UE during the two or more synchronization signal block reception opportunities of the one or more discovery reference signal windows based on the configuration. The SSB transmission component 935 may be configured as or otherwise support a component for transmitting a second side link synchronization signal block message to a third UE during at least one of the two or more synchronization signal block transmission opportunities of the one or more discovery reference signal windows based on the configuration.

[0159] In some examples, to support receiving the signaling indicating the configuration, the configuration signaling interface 925 may be configured as or otherwise support a component for receiving signaling indicating a receive discovery reference signal window and a send discovery reference signal window, wherein the receive discovery reference signal window includes the two or more synchronization signal block receive opportunities and the send discovery reference signal window includes the two or more synchronization signal block send opportunities.

[0160] In some examples, to support receiving the signaling indicating the configuration, the configuration signaling interface 925 may be configured as or otherwise support a component for receiving signaling indicating a discovery reference signal window, which includes the two or more synchronization signal block reception opportunities and the two or more synchronization signal block transmission opportunities.

[0161] In some examples, to support receiving the signaling indicating the configuration, the SSB timing configuration interface 940 may be configured as or otherwise support a component for receiving an indication of a first number of opportunities for sending the two or more synchronization signal blocks, a second number of opportunities for receiving the two or more synchronization signal blocks, or both the first number and the second number.

[0162] Additionally or alternatively, according to examples as disclosed herein, the communication manager 920 may support wireless communication at the first UE. In some examples, the configuration signaling interface 925 may be configured as or otherwise support a component for receiving signaling indicating a configuration for one or more discovery reference signal windows, each of the one or more discovery reference signal windows including a first synchronization signal block opportunity, a second synchronization signal block opportunity, and an additional synchronization signal block transmission opportunity set, the first synchronization signal block opportunity being used for sending a first side link synchronization signal block message by the second UE, the second synchronization signal block opportunity being used for sending a second side link synchronization signal block message by the first UE, and the additional synchronization signal block transmission opportunity set being configured for use by any UE in the UE set including the first UE and the second UE. In some examples, the SSB monitoring component 930 may be configured as or otherwise support a component for monitoring the second UE's transmission of the first side link synchronization signal block message during the first synchronization signal block opportunity of the one or more discovery reference signal windows based on the configuration. In some examples, the SSB transmission component 935 may be configured as or otherwise support a component for attempting to transmit the second side link synchronization signal block message during the second synchronization signal block opportunity of the one or more discovery reference signal windows based on the configuration. In some examples, the SSB reception component 960 may be configured as or otherwise support a component for the first UE to monitor the second UE's transmission of the first side link synchronization signal block message during the additional synchronization signal block transmission opportunity set based on whether the first UE received the first side link synchronization signal block message during the first synchronization signal block opportunity, and the additional opportunity component 945 may be configured as or otherwise support a component for the first UE to transmit the second side link synchronization signal block message during the additional synchronization signal block transmission opportunity set based on whether the first UE transmitted the second side link synchronization signal block message during the second synchronization signal block opportunity.

[0163] In some examples, the additional timing component 945 may be configured as or otherwise support a component for sending the second side link synchronization signal block message during a synchronization signal block transmission opportunity in the additional synchronization signal block transmission opportunity set based on a failure of the listen-before-talk procedure during the second synchronization signal block opportunity.

[0164] In some examples, the SSB absence component 950 may be configured as or otherwise support a component for determining that the first side link synchronization signal block message is not present in the first synchronization signal block opportunity based on the monitoring during the first synchronization signal block opportunity. In some examples, the SSB monitoring component 930 may be configured as or otherwise support a component for monitoring the second UE's transmission of the first side link synchronization signal block message during a synchronization signal block transmission opportunity in the set of additional synchronization signal block transmission opportunities based on the absence of the first side link synchronization signal block message in the first synchronization signal block opportunity.

[0165] In some examples, the synchronization accuracy component 955 may be configured as or otherwise support a component for determining that the synchronization accuracy of the first UE is below a synchronization accuracy threshold. In some examples, the SSB monitoring component 930 may be configured as or otherwise support a component for monitoring the second UE's transmission of the first sidelink synchronization signal block message during a synchronization signal block transmission opportunity in the additional synchronization signal block transmission opportunity set based on determining that the synchronization accuracy of the first UE is below the synchronization accuracy threshold.

[0166] In some examples, the synchronization accuracy component 955 may be configured as or otherwise support a component for determining that the synchronization accuracy of the first UE satisfies a synchronization accuracy threshold, wherein the first UE sends the second side link synchronization signal block message in response to determining that the synchronization accuracy of the first UE satisfies the synchronization accuracy threshold.

[0167] In some examples, the SSB receiving component 960 may be configured as or otherwise support a component for receiving the first side link synchronization signal block message from the second UE based on the monitoring, wherein the first UE sends the second side link synchronization signal block message during at least one synchronization signal block sending opportunity in response to receiving the first side link synchronization signal block message during at least one synchronization signal block receiving opportunity among the two or more synchronization signal block receiving opportunities.

[0168] In some examples, the SSB receiving component 960 may be configured as or otherwise support a component for the first UE to receive the first side link synchronization signal block message during a first additional synchronization signal block transmission opportunity in the set of additional synchronization signal block transmission opportunities. In some examples, the SSB transmitting component 935 may be configured as or otherwise support a component for transmitting the second side link synchronization signal block message during a second additional synchronization signal block transmission opportunity in the set of additional synchronization signal block transmission opportunities based at least in part on receiving the first side link synchronization signal block message during the first additional synchronization signal block transmission opportunity.

[0169] In some examples, the LBT component 965 may be configured as or otherwise support a component for performing a listen-before-talk procedure during the one or more discovery reference signal windows, wherein the first UE sends the second side link synchronization signal block message in response to clearing the listen-before-talk procedure.

[0170] Fig.10 A diagram of a system 1000 including a device 1005 supporting a discovery reference signal window configuration for a sidelink according to one or more aspects of the present disclosure is shown. The device 1005 may be an example of a device 705, a device 805, or a UE 115 as described herein, or include components thereof. 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 two-way voice and data communications, including components for sending and receiving communications, such as a communication manager 1020, an input / output (I / O) controller 1010, a transceiver 1015, an antenna 1025, a memory 1030, a code 1035, and a processor 1040. These components may be electronically communicated or otherwise coupled (e.g., operatively, communicatively, functionally, electronically, electrically) via one or more buses (e.g., a bus 1045).

[0171] I / O controller 1010 can manage input signals and output signals of device 1005. I / O controller 1010 can also manage peripheral devices that are not integrated into device 1005. In some cases, I / O controller 1010 can represent a physical connection or port to an external peripheral device. In some cases, I / O controller 1010 can utilize an operating system, such as or another known operating system. Additionally or alternatively, I / O controller 1010 may represent or interact with a modem, keyboard, mouse, touch screen, or similar device. In some cases, I / O controller 1010 may be implemented as part of a processor (such as processor 1040). In some cases, a user may interact with device 1005 via I / O controller 1010 or via hardware components controlled by I / O controller 1010.

[0172] 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 bidirectionally via one or more antennas 1025, a wired link, or a wireless link as described herein. For example, the transceiver 1015 may represent a wireless transceiver and may communicate bidirectionally with another wireless transceiver. The transceiver 1015 may also include a modem for modulating packets, providing the modulated packets to one or more antennas 1025 for transmission, and for demodulating packets received from one or more antennas 1025. The transceiver 1015, or the transceiver 1015 and one or more antennas 1025 may be examples of transmitters 715, transmitters 815, receivers 710, receivers 810, or any combination thereof or any components thereof as described herein.

[0173] The memory 1030 may include random access memory (RAM) and read-only memory (ROM). The memory 1030 may store computer-readable, computer-executable 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 (for example, when compiled and executed) cause the computer to perform the functions described herein. In some cases, in addition to this, the memory 1030 may also contain a basic I / O system (BIOS) that may control basic hardware or software operations, such as interaction with peripheral components or devices.

[0174] 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, processor 1040 may be configured to operate a memory array using a memory controller. In some other cases, the memory controller may be integrated into processor 1040. Processor 1040 may be configured to execute computer-readable instructions stored in a memory (e.g., memory 1030) to enable device 1005 to perform various functions (e.g., various functions or tasks supporting the discovery of reference signal window configuration for a side link). For example, device 1005 or a component of device 1005 may include processor 1040 and memory 1030 coupled to or coupled to processor 1040, and processor 1040 and memory 1030 are configured to perform the various functions described herein.

[0175] Additionally or alternatively, according to the examples disclosed herein, the communication manager 1020 may support wireless communication at the first UE. For example, the communication manager 1020 may be configured as or otherwise support a component for receiving signaling indicating a configuration for one or more discovery reference signal windows, according to which the one or more discovery reference signal windows include two or more synchronization signal block reception opportunities and two or more synchronization signal block transmission opportunities. The communication manager 1020 may be configured as or otherwise support a component for monitoring the reception of a first side link synchronization signal block message from a second UE during the two or more synchronization signal block reception opportunities of the one or more discovery reference signal windows based on the configuration. The communication manager 1020 may be configured as or otherwise support a component for sending a second side link synchronization signal block message to a third UE during at least one of the two or more synchronization signal block transmission opportunities of the one or more discovery reference signal windows based on the configuration.

[0176] Additionally or alternatively, according to the examples disclosed herein, the communication manager 1020 may support wireless communication at the first UE. For example, the communication manager 1020 may be configured as or otherwise support a component for receiving signaling indicating a configuration for one or more discovery reference signal windows, each of the one or more discovery reference signal windows including a first synchronization signal block opportunity, a second synchronization signal block opportunity, and an additional synchronization signal block transmission opportunity set, the first synchronization signal block opportunity being used for the second UE to send a first side link synchronization signal block message, the second synchronization signal block opportunity being used for the first UE to send a second side link synchronization signal block message, and the additional synchronization signal block transmission opportunity set being configured for use by any UE in the UE set including the first UE and the second UE. The communication manager 1020 may be configured as or otherwise support a component for monitoring the second UE's transmission of the first side link synchronization signal block message during the first synchronization signal block opportunity of the one or more discovery reference signal windows based on the configuration. The communication manager 1020 may be configured as or otherwise support a component for attempting to send the second side link synchronization signal block message during the second synchronization signal block opportunity of the one or more discovery reference signal windows based on the configuration. In some examples, in order to attempt to send the side link synchronization signal block message, the communication manager 1020 may be configured as or otherwise support a component for the following operations: the first UE monitors the second UE's sending of the first side link synchronization signal block message during the additional synchronization signal block sending opportunity set based on whether the first UE receives the first side link synchronization signal block message during the first synchronization signal block opportunity, and the first UE sends the second side link synchronization signal block message during the additional synchronization signal block sending opportunity set based on whether the first UE sends the second side link synchronization signal block message during the second synchronization signal block opportunity.

[0177] By including or configuring the communication manager 1020 according to the examples described herein, the device 1005 can support a technique for improving communication reliability due to improved synchronization with the network. For example, by performing the S-SSB procedure according to the DRS window configuration described herein, synchronization information can be more efficiently notified to each UE, resulting in reliable improvement of communication through improved synchronization.

[0178] In some examples, the communication manager 1020 may be configured to perform various operations (e.g., receive, monitor, transmit) using or otherwise cooperating with the transceiver 1015, one or more antennas 1025, or any combination thereof. Although the communication manager 1020 is illustrated as a separate component, in some examples, one or more functions described with reference to the communication manager 1020 may be supported or performed by the processor 1040, the memory 1030, the code 1035, or any combination thereof. For example, the code 1035 may include instructions that are executable by the processor 1040 to cause the device 1005 to perform various aspects of the discovery reference signal window configuration for the sidelink as described herein, or the processor 1040 and the memory 1030 may be otherwise configured to perform or support such operations.

[0179] Fig.11 A flowchart illustrating a method 1100 for supporting a discovery reference signal window configuration for a sidelink according to one or more aspects of the present disclosure is shown. The operations of the method 1100 may be implemented by a UE or a component thereof as described herein. For example, the operations of the method 1100 may be implemented by a UE or a component thereof as described herein. Figures 1 to 10 The UE 115 described herein may be used to perform the functions described herein. In some examples, the 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 use dedicated hardware to perform various aspects of the described functions.

[0180] At 1105, the method may include receiving signaling indicating a configuration for one or more discovery reference signal windows, according to which the one or more discovery reference signal windows include two or more synchronization signal block reception opportunities and two or more synchronization signal block transmission opportunities. The operations of 1105 may be performed according to examples as disclosed herein. In some examples, aspects of the operations of 1105 may be performed by as described in reference Fig. 9 The configuration signaling interface 925 is used for execution.

[0181] At 1110, the method may include monitoring, based on the configuration, reception of a first sidelink synchronization signal block message from a second UE during the two or more synchronization signal block reception opportunities of the one or more discovery reference signal windows. The operations of 1110 may be performed according to examples as disclosed herein. In some examples, aspects of the operations of 1110 may be performed as described in reference to Fig. 9 The SSB monitoring component 930 is used to perform.

[0182] At 1115, the method may include, based on the configuration, sending a second sidelink synchronization signal block message to a third UE during at least one of the two or more synchronization signal block transmission opportunities of the one or more discovery reference signal windows. The operations of 1115 may be performed according to examples as disclosed herein. In some examples, aspects of the operations of 1115 may be performed as described in reference to Fig. 9 The SSB sending component 935 is used to execute.

[0183] Fig.12 A flowchart illustrating a method 1200 for supporting a discovery reference signal window configuration for a sidelink according to one or more aspects of the present disclosure is shown. The operations of the method 1200 may be implemented by a UE or a component thereof as described herein. For example, the operations of the method 1200 may be implemented by a UE or a component thereof as described herein. Figures 1 to 10 The UE 115 described herein may be used to perform the functions described herein. In some examples, the 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 use dedicated hardware to perform various aspects of the described functions.

[0184] At 1205, the method may include receiving signaling indicating a configuration for a receive discovery reference signal window and a transmit discovery reference signal window, the receive discovery reference signal window including two or more synchronization signal block receive opportunities, and the transmit discovery reference signal window including two or more synchronization signal block transmit opportunities. The operations of 1205 may be performed according to examples as disclosed herein. In some examples, aspects of the operations of 1205 may be performed by Fig. 9 The configuration signaling interface 925 is used for execution.

[0185] At 1210, the method may include monitoring, based on the configuration, the reception of a first sidelink synchronization signal block message from a second UE during the two or more synchronization signal block reception opportunities of the reception discovery reference signal window. The operations of 1210 may be performed according to examples as disclosed herein. In some examples, aspects of the operations of 1210 may be performed as described in reference to Fig. 9 The SSB monitoring component 930 is used to perform.

[0186] At 1215, the method may include, based on the configuration, sending a second sidelink synchronization signal block message to a third UE during at least one of the two or more synchronization signal block transmission opportunities of the transmission discovery reference signal window. The operations of 1215 may be performed according to examples as disclosed herein. In some examples, aspects of the operations of 1215 may be performed as described in reference to Fig. 9 The SSB sending component 935 is used to execute.

[0187] Fig.13A flowchart illustrating a method 1300 for supporting a discovery reference signal window configuration for a sidelink according to one or more aspects of the present disclosure is shown. The operations of the method 1300 may be implemented by a UE or a component thereof as described herein. For example, the operations of the method 1300 may be implemented by a UE or a component thereof as described herein. Figures 1 to 10 The UE 115 described herein may be used to perform the functions described herein. In some examples, the 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 use dedicated hardware to perform various aspects of the described functions.

[0188] At 1305, the method may include receiving signaling indicating a configuration for a discovery reference signal window, the discovery reference signal window including two or more synchronization signal block reception opportunities and two or more synchronization signal block transmission opportunities. The operations of 1305 may be performed according to examples as disclosed herein. In some examples, aspects of the operations of 1305 may be performed by as described in reference Fig. 9 The configuration signaling interface 925 is used for execution.

[0189] At 1310, the method may include monitoring, based on the configuration, reception of a first sidelink synchronization signal block message from a second UE during the two or more synchronization signal block reception opportunities of the discovery reference signal window. The operations of 1310 may be performed according to examples as disclosed herein. In some examples, aspects of the operations of 1310 may be performed by Fig. 9 The SSB monitoring component 930 is used to perform.

[0190] At 1315, the method may include, based on the configuration, sending a second sidelink synchronization signal block message to a third UE during at least one of the two or more synchronization signal block transmission opportunities of the discovery reference signal window. The operations of 1315 may be performed according to examples as disclosed herein. In some examples, aspects of the operations of 1315 may be performed as described in reference to Fig. 9 The SSB sending component 935 is used to execute.

[0191] Fig.14 A flowchart illustrating a method 1400 for supporting a discovery reference signal window configuration for a sidelink according to one or more aspects of the present disclosure is shown. The operations of the method 1400 may be implemented by a UE or a component thereof as described herein. For example, the operations of the method 1400 may be implemented by a UE or a component thereof as described herein. Figures 1 to 10 The UE 115 described herein may be used to perform the functions described herein. In some examples, the 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 use dedicated hardware to perform various aspects of the described functions.

[0192] At 1405, the method may include receiving signaling indicating a configuration for one or more discovery reference signal windows, each of the one or more discovery reference signal windows including a first synchronization signal block opportunity, a second synchronization signal block opportunity, and an additional synchronization signal block transmission opportunity set, the first synchronization signal block opportunity being used by the second UE to transmit a first sidelink synchronization signal block message, the second synchronization signal block opportunity being used by the first UE to transmit a second sidelink synchronization signal block message, and the additional synchronization signal block transmission opportunity set being configured to be used by any UE in a UE set including the first UE and the second UE. The operations of 1405 may be performed according to examples as disclosed herein. In some examples, aspects of the operations of 1405 may be performed by reference to Fig. 9 The configuration signaling interface 925 is used for execution.

[0193] At 1410, the method may include monitoring, based on the configuration, the transmission of the first sidelink synchronization signal block message by the second UE during the first synchronization signal block opportunity of the one or more discovery reference signal windows. The operations of 1410 may be performed according to examples as disclosed herein. In some examples, aspects of the operations of 1410 may be performed by Fig. 9 The SSB monitoring component 930 is used to perform.

[0194] At 1415, the method may include, based on the configuration, attempting to send the second sidelink synchronization signal block message during the second synchronization signal block opportunity of the one or more discovery reference signal windows. The operations of 1415 may be performed according to examples as disclosed herein. In some examples, aspects of the operations of 1415 may be performed as described in reference to Fig. 9 The SSB sending component 935 is used to execute.

[0195] In some examples, whether the first UE monitors the second UE's transmission of the first side link synchronization signal block message during the additional synchronization signal block transmission opportunity set is based on whether the first UE receives the first side link synchronization signal block message during the first synchronization signal block opportunity. For example, if the first UE does not receive the first side link synchronization signal block message during the first synchronization signal block opportunity, the method may include monitoring the second UE's transmission of the first side link synchronization signal block message during the additional synchronization signal block transmission opportunity set at 1420. If the first UE receives the first side link synchronization signal block message during the first synchronization signal block opportunity, the first UE may not monitor the second UE's transmission of the first side link synchronization signal block message during the additional synchronization signal block transmission opportunity set. The operation of 1420 may be performed according to the examples disclosed herein. In some examples, various aspects of the operation of 1420 may be performed as described in reference to Fig. 9The SSB monitoring component 930 is used to perform.

[0196] Additionally or alternatively, whether the first UE sends the second side link synchronization signal block message during the additional synchronization signal block sending opportunity set is based on whether the first UE sends the second side link synchronization signal block message during the second synchronization signal block opportunity. For example, if the second side link synchronization signal block message is not sent during the second synchronization signal block opportunity, the method may include sending the second side link synchronization signal block message during the additional synchronization signal block sending opportunity set at 1425. If the second side link synchronization signal block message is sent during the second synchronization signal block opportunity, the first UE may not send the second side link synchronization signal block message during the additional synchronization signal block sending opportunity set. The operation of 1425 may be performed according to the examples disclosed herein. In some examples, aspects of the operation of 1425 may be performed as described in reference to Fig. 9 The SSB sending component 935 is used to execute.

[0197] The following provides an overview of various aspects of the disclosure:

[0198] Aspect 1: A method for performing wireless communications at a first UE, the method comprising: receiving signaling indicating a configuration for one or more discovery reference signal windows, according to which the one or more discovery reference signal windows include two or more synchronization signal block reception opportunities and two or more synchronization signal block transmission opportunities; based at least in part on the configuration, monitoring the reception of a first side link synchronization signal block message from a second UE during the two or more synchronization signal block reception opportunities of the one or more discovery reference signal windows; and based at least in part on the configuration, sending a second side link synchronization signal block message to a third UE during at least one of the two or more synchronization signal block transmission opportunities of the one or more discovery reference signal windows.

[0199] Aspect 2: A method according to Aspect 1, wherein receiving the signaling indicating the configuration includes: receiving signaling indicating a receiving discovery reference signal window and a sending discovery reference signal window, the receiving discovery reference signal window includes the two or more synchronization signal block receiving opportunities, and the sending discovery reference signal window includes the two or more synchronization signal block sending opportunities.

[0200] Aspect 3: The method according to aspect 2, wherein the resources of the discovery reference signal reception window and the resources of the discovery reference signal transmission window do not overlap in the time domain.

[0201] Aspect 4: The method according to any one of aspects 2 to 3, wherein the resources of the discovery reference signal reception window and the resources of the discovery reference signal transmission window at least partially overlap in the time domain.

[0202] Aspect 5: The method according to Aspect 4, wherein at least one of the synchronization signal block reception opportunities is positioned in the time domain between at least two of the synchronization signal block transmission opportunities.

[0203] Aspect 6: The method according to any one of aspects 2 to 5, wherein the resources of the discovery reference signal reception window and the resources of the discovery reference signal transmission window do not overlap in the frequency domain.

[0204] Aspect 7: A method according to aspect 1, wherein receiving the signaling indicating the configuration includes: receiving signaling indicating a discovery reference signal window, the discovery reference signal window including the two or more synchronization signal block reception opportunities and the two or more synchronization signal block transmission opportunities.

[0205] Aspect 8: The method according to Aspect 7, wherein at least one of the synchronization signal block reception opportunities is positioned in the time domain between at least two of the synchronization signal block transmission opportunities.

[0206] Aspect 9: A method according to any one of Aspects 1 to 8, wherein receiving the signaling indicating the configuration includes: receiving an indication of a first number of opportunities for sending the two or more synchronization signal blocks, a second number of opportunities for receiving the two or more synchronization signal blocks, or both the first number and the second number.

[0207] Aspect 10: A method according to any one of Aspects 1 to 9, wherein receiving the signaling indicating the configuration includes: receiving an indication of the spacing in the time domain between a first synchronization signal block opportunity and a second synchronization signal block opportunity of the one or more discovery reference signal windows.

[0208] Aspect 11: The method according to aspect 10, wherein the indication of the spacing indicates a number of time slots.

[0209] Aspect 12: The method according to aspect 11, wherein the indicated number of time slots is 0.

[0210] Aspect 13: According to the method described in any one of Aspects 1 to 12, the method further includes: performing a listen-before-talk procedure during the one or more discovery reference signal windows, wherein the first UE sends the second side link synchronization signal block message in response to clearing the listen-before-talk procedure.

[0211] Aspect 14: According to the method described in any one of Aspects 1 to 13, the method further includes: receiving the first side link synchronization signal block message from the second UE based at least in part on the monitoring, wherein the first UE sends the second side link synchronization signal block message during at least one synchronization signal block sending opportunity in response to receiving the first side link synchronization signal block message during at least one synchronization signal block receiving opportunity among the two or more synchronization signal block receiving opportunities.

[0212] Aspect 15: According to the method described in any one of Aspects 1 to 14, the method further includes: determining that the synchronization accuracy of the first UE satisfies a synchronization accuracy threshold, wherein the first UE sends the second side link synchronization signal block message in response to determining that the synchronization accuracy of the first UE satisfies the synchronization accuracy threshold.

[0213] Aspect 16: A method according to any one of Aspects 1 to 15, wherein each of the two or more synchronization signal block reception opportunities and each of the two or more synchronization signal block transmission opportunities correspond to corresponding time slots of the one or more discovery reference signal windows.

[0214] Aspect 17: A method for wireless communication at a first UE, the method comprising: receiving signaling indicating a configuration for one or more discovery reference signal windows, each of the one or more discovery reference signal windows comprising a first synchronization signal block opportunity, a second synchronization signal block opportunity, and an additional synchronization signal block sending opportunity set, the first synchronization signal block opportunity being used by a second UE to send a first side link synchronization signal block message, the second synchronization signal block opportunity being used by the first UE to send a second side link synchronization signal block message, and the additional synchronization signal block sending opportunity set being configured to be used by any UE in a UE set including the first UE and the second UE; and monitoring during the first synchronization signal block opportunity of the one or more discovery reference signal windows based at least in part on the configuration. monitoring the sending of the first side link synchronization signal block message by the second UE during the additional synchronization signal block sending opportunity set; and attempting to send the second side link synchronization signal block message during the second synchronization signal block opportunity of the one or more discovery reference signal windows based at least in part on the configuration, wherein: whether the first UE monitors the sending of the first side link synchronization signal block message by the second UE during the additional synchronization signal block sending opportunity set is based at least in part on whether the first UE receives the first side link synchronization signal block message during the first synchronization signal block opportunity; and whether the first UE sends the second side link synchronization signal block message during the additional synchronization signal block sending opportunity set is based at least in part on whether the first UE sends the second side link synchronization signal block message during the second synchronization signal block opportunity.

[0215] Aspect 18: A method according to Aspect 17, wherein attempting to send the second side link synchronization signal block message during the second synchronization signal block opportunity includes performing a listen-before-talk procedure during the second synchronization signal block opportunity, and the method further includes: sending the second side link synchronization signal block message during a synchronization signal block sending opportunity in the additional synchronization signal block sending opportunity set based at least in part on the failure of the listen-before-talk procedure during the second synchronization signal block opportunity.

[0216] Aspect 19: According to the method described in any one of Aspects 17 to 18, the method further includes: determining that the first side link synchronization signal block message does not exist in the first synchronization signal block opportunity based at least in part on the monitoring during the first synchronization signal block opportunity; and monitoring the sending of the first side link synchronization signal block message by the second UE during the synchronization signal block sending opportunity in the additional synchronization signal block sending opportunity set based at least in part on the absence of the first side link synchronization signal block message in the first synchronization signal block opportunity.

[0217] Aspect 20: According to the method described in any one of Aspects 17 to 19, the method further includes: determining that the synchronization accuracy of the first UE is lower than a synchronization accuracy threshold; and at least partially based on determining that the synchronization accuracy of the first UE is lower than the synchronization accuracy threshold, monitoring the sending of the first sidelink synchronization signal block message by the second UE during the synchronization signal block sending timing in the additional synchronization signal block sending timing set.

[0218] Aspect 21: According to the method described in any one of Aspects 17 to 20, the method further includes: receiving the first side link synchronization signal block message during the first additional synchronization signal block sending opportunity in the additional synchronization signal block sending opportunity set; and sending the second side link synchronization signal block message during the second additional synchronization signal block sending opportunity in the additional synchronization signal block sending opportunity set based at least in part on receiving the first side link synchronization signal block message during the first additional synchronization signal block sending opportunity.

[0219] Aspect 22: A method according to any one of Aspects 17 to 21, wherein each of the first synchronization signal block opportunity, the second synchronization signal block opportunity and the additional synchronization signal block sending opportunity corresponds to a corresponding time slot of the one or more discovery reference signal windows.

[0220] Aspect 23: An apparatus for performing wireless communications at a first UE, the apparatus comprising: a processor; a memory coupled to the processor; and instructions stored in the memory and executable by the processor to cause the apparatus to perform a method according to any one of Aspects 1 to 16.

[0221] Aspect 24: An apparatus for wireless communication at a first UE, the apparatus comprising at least one component for performing a method according to any one of aspects 1 to 16.

[0222] Aspect 25: A non-transitory computer-readable medium storing a code for wireless communication at a first UE, the code comprising instructions executable by a processor to perform a method according to any one of aspects 1 to 16.

[0223] Aspect 26: An apparatus for performing wireless communications at a first UE, the apparatus comprising: a processor; a memory coupled to the processor; and instructions stored in the memory and executable by the processor to cause the apparatus to perform a method according to any one of Aspects 17 to 22.

[0224] Aspect 27: An apparatus for wireless communication at a first UE, the apparatus comprising at least one component for performing a method according to any one of aspects 17 to 22.

[0225] 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 according to any one of aspects 17 to 22.

[0226] It should be noted that the methods described herein describe possible implementations, and that the operations and steps may be rearranged or otherwise modified and that other implementations are possible. In addition, aspects of two or more of the methods described may be combined.

[0227] Although aspects of LTE, LTE-A, LTE-A Pro, or NR systems may be described for example purposes, and LTE, LTE-A, LTE-A Pro, or NR terminology may be used in much of the description, the techniques described herein may also be applicable to networks other than LTE, LTE-A, LTE-A Pro, or NR networks. For example, the techniques described may be applicable to various other wireless communication systems, such as Ultra Mobile Broadband (UMB), Institute of Electrical and Electronics Engineers (IEEE) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, Flash-OFDM, and other systems and radio technologies not explicitly mentioned herein.

[0228] The information and signals described herein may be represented using any of a variety of different technologies and methods. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be mentioned throughout the specification may be represented by voltage, current, electromagnetic waves, magnetic fields or magnetic particles, optical fields or optical particles, or any combination thereof.

[0229] The various illustrative blocks and components described in conjunction with the disclosure herein may be implemented or performed using a general purpose processor, DSP, ASIC, CPU, FPGA or other programmable logic device, discrete gate or transistor logic components, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general purpose processor may be a microprocessor, but in an alternative, the processor may be any processor, controller, microcontroller, or state machine. The processor may also be implemented as a combination of computing devices (e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration).

[0230] 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 one or more instructions or codes of a computer-readable medium, or sent using one or more instructions or codes of a computer-readable medium. Other examples and specific implementations are within the scope of this disclosure and the appended claims. For example, due to the nature of software, the functions described herein may be implemented using software executed by a processor, hardware, firmware, hard wiring, or a combination of any of these items. Features that implement the functions may also be physically located at different locations, including being distributed so that the functions are implemented at different physical locations.

[0231] Computer-readable medium includes both non-transient computer storage medium and communication medium, and the communication medium includes any medium that promotes computer program to be transferred from one position to another position.Non-transient storage medium can be any available medium that can be accessed by general or special-purpose computer.By way of example and not limitation, non-transient computer-readable medium can include RAM, ROM, electrically erasable programmable ROM (EEPROM), flash memory, compact disc (CD) ROM or other optical disc storage device, disk storage device or other magnetic storage device, or can be used for carrying or storing desired program code parts and can be accessed by general or special-purpose computer or general or special-purpose processor in the form of instruction or data structure Any other non-transient medium.In addition, any connection is appropriately referred to as computer-readable medium.For example, if software is sent from website, server or other remote source using coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL) or wireless technology such as infrared, radio and microwave, then coaxial cable, fiber optic cable, twisted pair, DSL or wireless technology such as infrared, radio and microwave are included in the definition of computer-readable medium. As used herein, disks and optical disks include CDs, laser disks, optical disks, digital versatile disks (DVDs), floppy disks, and Blu-ray disks. Disks can reproduce data magnetically, and optical disks can reproduce data optically using lasers. Combinations of the above are also included within the scope of computer-readable media.

[0232] As used herein (including in the claims), "or" used in a list of items (e.g., a list of items with a phrase such as "at least one of" or "one or more of") indicates an inclusive list, so 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). In addition, as used herein, the phrase "based on" should not be interpreted as a reference to a closed set of conditions. For example, an example step described as "based on condition A" may be based on both condition A and condition B without departing from the scope of the present disclosure. In other words, as used herein, the phrase "based on" should be interpreted in the same manner as the phrase "based at least in part on". In addition, as used herein, the phrase "set" should be interpreted to include the possibility of a set having one member. That is, the phrase "set" should be interpreted in the same manner as "one or more".

[0233] The term "determining" encompasses various actions, and thus, "determining" may include calculating, computing, processing, deriving, investigating, looking up (such as via looking up in a table, database or other data structure), ascertaining, etc. Additionally, "determining" may include receiving (e.g., receiving information), accessing (e.g., accessing data stored in a memory), etc. Additionally, "determining" may include resolving, obtaining, selecting, choosing, establishing, and other such similar actions.

[0234] In the drawings, similar components or features may have the same reference label. In addition, various components of the same type may be distinguished by following the reference label with a dash and a second label to distinguish between the similar components. If only the first reference label is used in the specification, the description may apply to any of the similar components having the same first reference label, regardless of the second reference label or other subsequent reference labels.

[0235] The descriptions set forth herein in conjunction with the accompanying drawings describe example configurations and do not represent all examples that may be implemented or within the scope of the claims. The term "example" as used herein means "used as an example, instance, or illustration," rather than "preferred" or "having advantages over other examples." The specific embodiments include specific details to provide an understanding of the described techniques. However, these techniques may be practiced without these specific details. In some instances, known structures and devices are shown in block diagram form to avoid obscuring the concepts of the described examples.

[0236] The description herein is provided to enable one of ordinary skill in the art to implement or use the present disclosure. Various modifications to the present disclosure will be apparent to one of ordinary skill in the art, and the general principles defined herein may be applied to other variations without departing from the scope of the present disclosure. Thus, the present disclosure is not limited to the examples and designs described herein, but should be granted the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An apparatus for wireless communication at a first user equipment (UE), the apparatus comprising: processor; a memory coupled to the processor; and instructions stored in the memory and executable by the processor to cause the apparatus to: receiving signaling indicating a configuration for one or more discovery reference signal windows, wherein the one or more discovery reference signal windows include two or more synchronization signal block reception opportunities and two or more synchronization signal block transmission opportunities according to the configuration; Based at least in part on the configuration, monitoring reception of a first sidelink synchronization signal block message from a second UE during the two or more synchronization signal block reception opportunities of the one or more discovery reference signal windows; as well as Based at least in part on the configuration, a second sidelink synchronization signal block message is sent to a third UE during at least one synchronization signal block transmission opportunity of the two or more synchronization signal block transmission opportunities of the one or more discovery reference signal windows.

2. The device according to claim 1, wherein: In order to receive the signaling indicative of the configuration, the instructions are executable by the processor to cause the apparatus to: Signaling indicating a receive discovery reference signal window and a send discovery reference signal window is received, wherein the receive discovery reference signal window includes the two or more synchronization signal block receive opportunities and the send discovery reference signal window includes the two or more synchronization signal block send opportunities. 3 . The apparatus according to claim 2 , wherein the resources of the discovery reference signal reception window and the resources of the discovery reference signal transmission window do not overlap in the time domain. 4 . The apparatus according to claim 2 , wherein the resources of the receiving discovery reference signal window and the resources of the sending discovery reference signal window at least partially overlap in the time domain.

5. The apparatus according to claim 4, wherein at least one of the synchronization signal block reception opportunities is positioned in the time domain between at least two of the synchronization signal block transmission opportunities. 6 . The apparatus according to claim 2 , wherein the resources of the receiving discovery reference signal window and the resources of the sending discovery reference signal window do not overlap in the frequency domain.

7. The device according to claim 1, wherein: In order to receive the signaling indicative of the configuration, the instructions are executable by the processor to cause the apparatus to: Signaling indicating a discovery reference signal window is received, the discovery reference signal window including the two or more synchronization signal block reception opportunities and the two or more synchronization signal block transmission opportunities.

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

9. The device according to claim 1, wherein: In order to receive the signaling indicative of the configuration, the instructions are executable by the processor to cause the apparatus to: An indication of a first number of the two or more synchronization signal block transmit opportunities, a second number of the two or more synchronization signal block receive opportunities, or both the first number and the second number is received.

10. The device according to claim 1, wherein: In order to receive the signaling indicative of the configuration, the instructions are executable by the processor to cause the apparatus to: An indication of a spacing in the time domain between a first synchronization signal block opportunity and a second synchronization signal block opportunity of the one or more discovery reference signal windows is received.

11. The apparatus of claim 10, wherein the indication of the spacing indicates a number of time slots. The apparatus of claim 11 , wherein the indicated number of time slots is 0.

13. The apparatus of claim 1, wherein the instructions are further executable by the processor to cause the apparatus to: A listen-before-talk procedure is performed during the one or more discovery reference signal windows, wherein the instructions are executable by the processor to cause the apparatus to send 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: Based at least in part on the monitoring, the first sidelink synchronization signal block message is received from the second UE, wherein the instructions are executable by the processor to cause the device to send the second sidelink synchronization signal block message during at least one synchronization signal block sending opportunity in response to receiving the first sidelink synchronization signal block message during at least one synchronization signal block receiving opportunity among the two or more synchronization signal block receiving opportunities.

15. The apparatus of claim 1, wherein the instructions are further executable by the processor to cause the apparatus to: Determine that the synchronization accuracy of the first UE satisfies a synchronization accuracy threshold, wherein the instruction is executable by the processor to cause the device to send the second sidelink synchronization signal block message in response to determining that the synchronization accuracy of the first UE satisfies the synchronization accuracy threshold.

16. An apparatus according to claim 1, wherein each of the two or more synchronization signal block reception opportunities and each of the two or more synchronization signal block transmission opportunities correspond to a corresponding time slot of the one or more discovery reference signal windows.

17. An apparatus for wireless communication at a first user equipment (UE), the apparatus comprising: processor; a memory coupled to the processor; and instructions stored in the memory and executable by the processor to cause the apparatus to: receiving signaling indicating configuration for one or more discovery reference signal windows, each of the one or more discovery reference signal windows comprising a first synchronization signal block opportunity, a second synchronization signal block opportunity, and an additional synchronization signal block sending opportunity set, the first synchronization signal block opportunity being used by a second UE to send a first sidelink synchronization signal block message, the second synchronization signal block opportunity being used by the first UE to send a second sidelink synchronization signal block message, and the additional synchronization signal block sending opportunity set being configured to be used by any UE in a UE set including the first UE and the second UE; Based at least in part on the configuration, monitoring the second UE for sending the first sidelink synchronization signal block message during the first synchronization signal block opportunities of the one or more discovery reference signal windows; as well as Attempting to send the second sidelink synchronization signal block message during the second synchronization signal block opportunity of the one or more discovery reference signal windows based at least in part on the configuration, wherein: Whether the first UE monitors the transmission of the first sidelink synchronization signal block message by the second UE during the set of additional synchronization signal block transmission opportunities is based at least in part on whether the first UE receives the first sidelink synchronization signal block message during the first synchronization signal block opportunity; and Whether the first UE sends the second sidelink synchronization signal block message during the additional synchronization signal block transmission opportunity set is based at least in part on whether the first UE sends the second sidelink synchronization signal block message during the second synchronization signal block opportunity.

18. The device according to claim 17, wherein: 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 opportunity in order to attempt to send the second sidelink synchronization signal block message during the second synchronization signal block opportunity; and The instructions are also executable by the processor to cause the device to send the second sidelink synchronization signal block message during a synchronization signal block transmission opportunity in the additional synchronization signal block transmission opportunity set based at least in part on the failure of the listen-before-talk procedure during the second synchronization signal block opportunity.

19. The apparatus of claim 17, wherein the instructions are further executable by the processor to cause the apparatus to: determining, based at least in part on the monitoring during the first synchronization signal block opportunity, that the first sidelink synchronization signal block message is not present in the first synchronization signal block opportunity; and Based at least in part on the absence of the first sidelink synchronization signal block message in the first synchronization signal block opportunity, the sending of the first sidelink synchronization signal block message by the second UE is monitored during a synchronization signal block sending opportunity in the additional synchronization signal block sending opportunity set.

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

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

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

23. A method for wireless communication at a first user equipment (UE), the method comprising: receiving signaling indicating a configuration for one or more discovery reference signal windows, wherein the one or more discovery reference signal windows include two or more synchronization signal block reception opportunities and two or more synchronization signal block transmission opportunities according to the configuration; Based at least in part on the configuration, monitoring reception of a first sidelink synchronization signal block message from a second UE during the two or more synchronization signal block reception opportunities of the one or more discovery reference signal windows; as well as Based at least in part on the configuration, a second sidelink synchronization signal block message is sent to a third UE during at least one synchronization signal block transmission opportunity of the two or more synchronization signal block transmission opportunities of the one or more discovery reference signal windows.

24. The method of claim 23, wherein receiving the signaling indicating the configuration comprises: Signaling indicating a receive discovery reference signal window and a send discovery reference signal window is received, wherein the receive discovery reference signal window includes the two or more synchronization signal block receive opportunities and the send discovery reference signal window includes the two or more synchronization signal block send opportunities.

25. The method of claim 23, wherein receiving the signaling indicating the configuration comprises: Signaling indicating a discovery reference signal window is received, the discovery reference signal window including the two or more synchronization signal block reception opportunities and the two or more synchronization signal block transmission opportunities.

26. The method of claim 23, wherein receiving the signaling indicating the configuration comprises: An indication of a first number of the two or more synchronization signal block transmit opportunities, a second number of the two or more synchronization signal block receive opportunities, or both the first number and the second number is received.

27. A method for wireless communication at a first user equipment (UE), the method comprising: receiving signaling indicating configuration for one or more discovery reference signal windows, each of the one or more discovery reference signal windows comprising a first synchronization signal block opportunity, a second synchronization signal block opportunity, and an additional synchronization signal block sending opportunity set, the first synchronization signal block opportunity being used by a second UE to send a first sidelink synchronization signal block message, the second synchronization signal block opportunity being used by the first UE to send a second sidelink synchronization signal block message, and the additional synchronization signal block sending opportunity set being configured to be used by any UE in a UE set including the first UE and the second UE; Based at least in part on the configuration, monitoring the second UE for sending the first sidelink synchronization signal block message during the first synchronization signal block opportunities of the one or more discovery reference signal windows; as well as Attempting to send the second sidelink synchronization signal block message during the second synchronization signal block opportunity of the one or more discovery reference signal windows based at least in part on the configuration, wherein: Whether the first UE monitors the transmission of the first sidelink synchronization signal block message by the second UE during the set of additional synchronization signal block transmission opportunities is based at least in part on whether the first UE receives the first sidelink synchronization signal block message during the first synchronization signal block opportunity; and Whether the first UE sends the second sidelink synchronization signal block message during the additional synchronization signal block transmission opportunity set is based at least in part on whether the first UE sends the second sidelink synchronization signal block message during the second synchronization signal block opportunity.

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

29. The method according to claim 27, further comprising: determining, based at least in part on the monitoring during the first synchronization signal block opportunity, that the first sidelink synchronization signal block message is not present in the first synchronization signal block opportunity; as well as Based at least in part on the absence of the first sidelink synchronization signal block message in the first synchronization signal block opportunity, the sending of the first sidelink synchronization signal block message by the second UE is monitored during a synchronization signal block sending opportunity in the additional synchronization signal block sending opportunity set.

30. The method of claim 27, further comprising: Determining that a synchronization accuracy of the first UE is lower than a synchronization accuracy threshold; as well as Based at least in part on determining that the synchronization accuracy of the first UE is lower than the synchronization accuracy threshold, the transmission of the first sidelink synchronization signal block message by the second UE is monitored during a synchronization signal block transmission opportunity in the additional synchronization signal block transmission opportunity set.

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