Side-link candidate resource selection

Abstract

Methods, systems, and devices for wireless communication are described. A user equipment (UE) may measure a reference signal received power (RSRP) of a reference signal from other UEs in a time window and exclude resources of transmissions having measurements above an RSRP threshold. In some cases, insufficient resources are identified and the UE may increase the RSRP and search for resources again, but the UE may increase the RSRP only before reaching a stop RSRP limit. The UE may increase the RSRP based on a factor of an absolute value or an incremental power value. Once the stop RSRP threshold is reached, the UE may modify the size of the time window, move the time window, or reduce the number of retransmissions of sidelink messages to search for resources for sidelink messages.

Description

[0001] Cross - Reference to Related Applications

[0002] This patent application claims priority to U.S. Patent Application No. 17 / 090,068, entitled "SIDELINK CANDIDATE RESOURCE SELECTION," filed on November 5, 2020, by GULATI et al., which claims the benefit of U.S. Provisional Patent Application No. 62 / 933,239, entitled "SIDELINK CANDIDATE RESOURCE SELECTION," filed on November 8, 2019, by GULATI et al., and which is assigned to the assignee of the present application. Technical Field

[0003] The following generally relates to wireless communication and, more specifically, to sidelink candidate resource selection. Background Art

[0004] Wireless communication systems are widely deployed to provide various types of communication content, such as voice, video, packet data, messaging, broadcasting, etc. These systems are capable of supporting communication with multiple users by sharing available system resources (e.g., time, frequency, and power). Examples of such multi - access systems include fourth - generation (4G) systems such as Long - Term Evolution (LTE) systems, Advanced LTE (LTE - A) systems, or LTE - A Pro systems, and fifth - generation (5G) systems that may be referred to as New Radio (NR) systems. These systems may employ techniques such as Code Division Multiple Access (CDMA), Time Division Multiple Access (TDMA), Frequency Division Multiple Access (FDMA), Orthogonal Frequency Division Multiple Access (OFDMA), or Discrete Fourier Transform Spread Orthogonal Frequency Division Multiplexing (DFT - S - OFDM). A wireless multi - access communication system may include one or more base stations or one or more network access nodes, each of which simultaneously supports communication for multiple communication devices, which may also be referred to as user equipment (UE).

[0005] A UE may communicate with other UEs in a device - to - device (D2D) system, vehicle - to - everything (V2X), or other systems via a sidelink communication link. In some cases, such as when UEs are very close to each other, there may be a limited number of available resources for the UEs to perform sidelink transmissions. Traditional sidelink scheduling techniques may not fully address the problems caused by the limited resources available for sidelink communication, which may lead to conflicts, interference, lost transmissions, etc. between UE communications. Summary of the Invention

[0006] The described techniques relate to improved methods, systems, devices, and apparatuses for supporting sidelink candidate resource selection. Generally, the described techniques enable a user equipment (UE) to communicate with one or more UEs using time-frequency resources on a sidelink selected from a candidate resource pool. Before transmitting a transmission via the sidelink, the UE may determine available (e.g., candidate) time resources (e.g., time slots, subframes, etc.) and frequency resources (e.g., carriers, channels, resource blocks (RBs), subchannels) by excluding resources used by other UEs. For example, the UE may determine which resources to exclude by decoding control information received from other UEs (e.g., sidelink control information (SCI)) (e.g., the UE may monitor time-frequency resources from one or more neighboring UEs for SCI). The UE may also measure one or more signal characteristics (e.g., signal quality, signal power, interference measurement, reference signal received power (RSRP)) of signals from neighboring UEs (e.g., reference signals, control signals, data signals), or may consider the location information of neighboring UEs when determining resources available for sidelink communication.

[0007] According to some aspects, the UE may measure the RSRP of a reference signal associated with a control channel received from a neighboring UE within a time window, and if the RSRP measurement is above an RSRP threshold or within the RSRP threshold range (e.g., within an initial RSRP threshold and a stop RSRP threshold), may exclude the resources indicated by the control channel. In some cases, if a limited number of resources are identified as available for sidelink communication, the UE may increase the RSRP threshold (e.g., increase the initial RSRP threshold by an absolute value, a factor of an incremental value) and search for resources again. This may continue until a suitable number of resources are available, but the UE may only increase the RSRP threshold for resource selection until a stop RSRP limit is reached. Once the stop RSRP threshold is reached, the UE may modify the size of the time window, move the time window, reduce the number of retransmissions of the sidelink message, or any combination thereof, to search for resources for transmission of the sidelink message. In some examples, the base station may configure an exclusion range (i.e., resources to be excluded from consideration) or a configuration for increasing the RSRP threshold for the UE (e.g., a subset of values that the UE is able to use to increase the RSRP threshold).

[0008] A method of wireless communication at a first UE is described. The method may include determining a time window for resource selection for transmission of a sidelink message from the first UE to a second UE, determining, within the time window, a set of candidate resources for transmission of the sidelink message, the set of candidate resources corresponding to a threshold percentage of the total resources within the time window that is available for resource selection based on an initial power threshold, a stop power threshold, and power measurements associated with at least one neighboring UE, selecting a resource from the set of candidate resources for transmission of the sidelink message, and transmitting the sidelink message to the second UE via the selected resource.

[0009] An apparatus for wireless communication at a first UE is described. The apparatus may include a processor, a memory coupled to the processor, and instructions stored in the memory. The instructions may be executed by the processor to cause the apparatus to determine a time window for resource selection for transmission of a sidelink message from the first UE to a second UE, determine, within the time window, a set of candidate resources for transmission of the sidelink message, the set of candidate resources corresponding to a threshold percentage of the total resources within the time window that is available for resource selection based on an initial power threshold, a stop power threshold, and power measurements associated with at least one neighboring UE, select a resource from the set of candidate resources for transmission of the sidelink message, and transmit the sidelink message to the second UE via the selected resource.

[0010] Another apparatus for wireless communication at a first UE is described. The apparatus may include means for determining a time window for resource selection for transmission of a sidelink message from the first UE to a second UE, determining, within the time window, a set of candidate resources for transmission of the sidelink message, the set of candidate resources corresponding to a threshold percentage of the total resources within the time window that is available for resource selection based on an initial power threshold, a stop power threshold, and power measurements associated with at least one neighboring UE, selecting a resource from the set of candidate resources for transmission of the sidelink message, and transmitting the sidelink message to the second UE via the selected resource.

[0011] A non-transitory computer-readable medium storing code for wireless communication at a first UE is described. The code may include instructions executable by a processor to determine a time window for resource selection for transmission of a sidelink message from the first UE to a second UE, determine, within the time window, a set of candidate resources for transmission of the sidelink message, the set of candidate resources corresponding to a threshold percentage of the total resources within the time window that is available for resource selection based on an initial power threshold, a stop power threshold, and power measurements associated with at least one neighboring UE, select a resource from the set of candidate resources for transmission of the sidelink message, and transmit the sidelink message to the second UE via the selected resource.

[0012] Some examples of the methods, apparatuses, and non-transitory computer-readable media described herein may also include operations, features, components, or instructions for: determining the RSRP of a reference signal from at least one neighboring UE and determining a candidate resource set based on the RSRP, an initial power threshold, and a stop power threshold.

[0013] Some examples of the methods, apparatuses, and non-transitory computer-readable media described herein may also include operations, features, components, or instructions for: determining that the RSRP of the reference signal may be higher than the initial power threshold, increasing a power threshold for determining the candidate resource set, the power threshold being between the initial power threshold and the stop power threshold, and determining the candidate resource set based on the RSRP and the power threshold.

[0014] Some examples of the methods, apparatuses, and non-transitory computer-readable media described herein may also include operations, features, components, or instructions for: increasing the power threshold according to an absolute value, a factor of an incremental value, the number of retransmissions associated with a sidelink message, the priority of the sidelink message, a packet delay budget (PDB) associated with the sidelink message, the priority of a scheduled transmission of at least one neighboring UE, or any combination thereof.

[0015] Some examples of the methods, apparatuses, and non-transitory computer-readable media described herein may also include operations, features, components, or instructions for: inhibiting the increase of the power threshold beyond the stop power threshold.

[0016] Some examples of the methods, apparatuses, and non-transitory computer-readable media described herein may also include operations, features, components, or instructions for: increasing the size of a time window for resource selection for transmission of a sidelink message and determining the candidate resource set based on the increased size of the time window.

[0017] Some examples of the methods, apparatuses, and non-transitory computer-readable media described herein may also include operations, features, components, or instructions for: determining that the RSRP may be higher than the stop power threshold, wherein the size of the time window may be increased based on the determination that the RSRP may be higher than the stop power threshold.

[0018] Some examples of the methods, apparatuses, and non-transitory computer-readable media described herein may also include operations, features, components, or instructions for: moving the time window from a first start time to a second start time after the first start time and determining the candidate resource set based on the moved time window.

[0019] Some examples of the methods, apparatuses, and non-transitory computer-readable media described herein may also include operations, features, components, or instructions for: determining that the RSRP may be higher than a stop power threshold, wherein a time window may be shifted based on the determination that the RSRP may be higher than the stop power threshold.

[0020] Some examples of the methods, apparatuses, and non-transitory computer-readable media described herein may also include operations, features, components, or instructions for: receiving an indication of an exclusion range for resource selection for transmission of a sidelink message, and determining a candidate resource set based on the exclusion range, wherein the candidate resource set excludes resources specified by the exclusion range.

[0021] In some examples of the methods, apparatuses, and non-transitory computer-readable media described herein, the indication may be received from a base station via a control channel message.

[0022] Some examples of the methods, apparatuses, and non-transitory computer-readable media described herein may also include operations, features, components, or instructions for: determining the number of retransmissions associated with a sidelink message and determining the size of a time window based on the number of retransmissions.

[0023] Some examples of the methods, apparatuses, and non-transitory computer-readable media described herein may also include operations, features, components, or instructions for: determining that the RSRP of a reference signal from at least one neighboring UE may be higher than an initial power threshold, reducing the number of retransmissions associated with a sidelink message, increasing the size of a time window based on the reduced number of retransmissions, and determining a candidate resource set from the time window based on the increased size.

[0024] Some examples of the methods, apparatuses, and non-transitory computer-readable media described herein may also include operations, features, components, or instructions for: determining a time window based on a packet delay budget of a sidelink message.

[0025] Some examples of the methods, apparatuses, and non-transitory computer-readable media described herein may also include operations, features, components, or instructions for: receiving a configuration for increasing a power threshold for determining a candidate resource set and determining a candidate resource set based on the configuration.

[0026] In some examples of the methods, apparatuses, and non-transitory computer-readable media described herein, the configuration may be received from a base station via a control channel message.

[0027] Some examples of the methods, apparatuses, and non-transitory computer-readable media described herein may also include operations, features, components, or instructions for: determining that the RSRP of a reference signal from at least one neighboring UE may be higher than an initial power threshold, increasing a power threshold for determining a candidate resource set according to a configuration, and determining the candidate resource set after increasing the power threshold.

[0028] A method for wireless communication at a base station is described. The method may include establishing a communication link with a first UE communicating with a second UE via a sidelink communication link, determining a configuration for candidate resource selection for a sidelink message from the first UE to the second UE, the configuration being based on an initial power threshold and a stop power threshold, and transmitting an indication of the configuration to the first UE.

[0029] An apparatus for wireless communication at a base station is described. The apparatus may include a processor, a memory coupled to the processor, and instructions stored in the memory. The instructions may be executed by the processor to cause the apparatus to establish a communication link with a first UE communicating with a second UE via a sidelink communication link, determine a configuration for candidate resource selection for a sidelink message from the first UE to the second UE, the configuration being based on an initial power threshold and a stop power threshold, and transmit an indication of the configuration to the first UE.

[0030] Another apparatus for wireless communication at a base station is described. The apparatus may include components for: establishing a communication link with a first UE communicating with a second UE via a sidelink communication link, determining a configuration for candidate resource selection for a sidelink message from the first UE to the second UE, the configuration being based on an initial power threshold and a stop power threshold, and transmitting an indication of the configuration to the first UE.

[0031] A non-transitory computer-readable medium storing code for wireless communication at a base station is described. The code may include instructions executable by a processor to establish a communication link with a first UE communicating with a second UE via a sidelink communication link, determine a configuration for candidate resource selection for a sidelink message from the first UE to the second UE, the configuration being based on an initial power threshold and a stop power threshold, and transmit an indication of the configuration to the first UE.

[0032] In some examples of the methods, apparatuses, and non-transitory computer-readable media described herein, the configuration indication increases a power threshold for determining a candidate resource set for a sidelink message.

[0033] In some examples of the methods, apparatuses, and non-transitory computer-readable media described herein, the power threshold increase may be based on an absolute value, a factor of an incremental value, the number of retransmissions associated with a sidelink message, the priority of the sidelink message, the packet delay budget (PDB) associated with the sidelink message, the priority of a scheduled transmission of at least one neighboring UE, or any combination thereof.

[0034] Some examples of the methods, apparatuses, and non-transitory computer-readable media described herein may also include operations, features, components, or instructions for: transmitting an indication for determining an exclusion range of a candidate resource set for a sidelink message, where the exclusion range specifies resources to be excluded from the candidate resource set.

[0035] In some examples of the methods, apparatuses, and non-transitory computer-readable media described herein, the indication may be transmitted via a control channel message. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 FIG. illustrates an example of a wireless communication system supporting sidelink candidate resource selection in accordance with aspects of the present disclosure.

[0037] Figure 2 FIG. illustrates an example of a wireless communication system supporting sidelink candidate resource selection in accordance with aspects of the present disclosure.

[0038] Figure 3 FIG. illustrates an example of a resource selection scheme supporting sidelink candidate resource selection in accordance with aspects of the present disclosure.

[0039] Figure 4 FIG. illustrates an example of a processing flow supporting sidelink candidate resource selection in accordance with aspects of the present disclosure.

[0040] Figure 5 and Figure 6 FIG. shows a block diagram of a device supporting sidelink candidate resource selection in accordance with aspects of the present disclosure.

[0041] Figure 7 FIG. shows a block diagram of a communication manager supporting sidelink candidate resource selection in accordance with aspects of the present disclosure.

[0042] Figure 8 FIG. shows a diagram of a system including a device supporting sidelink candidate resource selection in accordance with aspects of the present disclosure.

[0043] Figure 9 and Figure 10 FIG. shows a block diagram of a device supporting sidelink candidate resource selection in accordance with aspects of the present disclosure.

[0044] Figure 11A block diagram of a communication manager supporting sidelink candidate resource selection in accordance with aspects of the present disclosure is shown.

[0045] Figure 12 A diagram of a system including a device supporting sidelink candidate resource selection in accordance with aspects of the present disclosure is shown.

[0046] Figures 13 to 16 A flowchart of a method supporting sidelink candidate resource selection in accordance with aspects of the present disclosure is shown. Detailed Description

[0047] A wireless communication system may support an access link and a sidelink for communication between wireless devices. The access link may refer to a communication link between a user equipment (UE) and a base station (or relay device). For example, the access link may support uplink signaling, downlink signaling, connection procedures, etc. One or more UEs connected to the base station via the access link may derive timing from the base station. The UE may also be an example of an integrated access and backhaul (IAB) node. The sidelink may refer to any communication link between similar wireless devices (e.g., a communication link between UEs, a backhaul communication link between base stations, etc.). Although various examples provided herein are discussed with respect to UE sidelink devices, such sidelink techniques may be used for any type of wireless device that uses sidelink communication. For example, the sidelink may support device-to-device (D2D) communication, vehicle-to-everything (V2X) or vehicle-to-vehicle (V2V) communication, message relaying, discovery signaling, beacon signaling, or any combination thereof, or other signals transmitted over the air from one wireless device to one or more other wireless devices.

[0048] As the demand for sidelink communication increases (due to increased V2X requirements for autonomous and semi-autonomous vehicles, D2D communication between Internet of Things (IoT) devices, factory automation, etc.), techniques for effectively and reliably increasing the throughput and reliability of the sidelink channel are desired. In some cases, techniques for coordinating resources for the sidelink and for reducing the number of sidelink retransmissions and improving the efficiency of transmitting and receiving UEs.

[0049] As more UEs perform sidelink communication, the availability of resources decreases. Before scheduling a sidelink transmission (e.g., via sidelink control information (SCI)), the UE may search for available resources in a time window. The time window may be defined by the processing time of the UE and the packet delay budget (PDB) of the sidelink message. The UE may determine available resources (i.e., candidate resources) based on a reference signal received power (RSRP) threshold and RSRP measurements of neighboring UEs. If there are not enough resources available for sidelink transmission within the time window, the RSRP threshold may be increased.

[0050] If insufficient resources are identified, the UE can increase the RSRP and search for resources again. If there are no restrictions on the RSRP threshold, the UE can continue to increase the RSRP threshold until sufficient resources are available, which may lead to conflicts with other UEs. In accordance with aspects of the present document, if insufficient resources are available, the UE can only increase the RSRP until the stop RSRP limit is reached. The UE can increase the RSRP based on a factor of an absolute value or an incremental power value. Once the stop RSRP threshold is reached, the UE can modify the size of the time window, shift the time window, or reduce the number of retransmissions of the sidelink message to search for resources for the sidelink message. In some cases, the base station can configure an exclusion range (i.e., resources excluded from consideration) or a configuration for increasing the RSRP threshold (e.g., a subset of values that the UE is capable of using to increase the RSRP threshold) for the UE.

[0051] Certain aspects of the subject matter described in this document can be implemented to realize one or more advantages. Among other advantages, the described techniques can also support improvements in selecting resources for sidelink communication, reducing interference or conflicts, and improving reliability. Thus, the supported techniques can include improved network operation and, in some examples, can also improve network efficiency, among other benefits.

[0052] Aspects of the present disclosure are initially described in the context of a wireless communication system. Resource selection schemes and procedures are then provided to illustrate aspects of the present disclosure. Aspects of the present disclosure are further illustrated by and described with reference to diagrams of apparatus, system diagrams, and flowcharts related to sidelink candidate resource selection.

[0053] Figure 1 An example of a wireless communication system 100 that supports sidelink candidate resource selection in accordance with aspects of the present disclosure is illustrated. The wireless communication system 100 can include one or more base stations 105, one or more UEs 115, and a core network 130. In some examples, the wireless communication system 100 can be a Long Term Evolution (LTE) network, an LTE-Advanced (LTE-A) network, an LTE-A Pro network, or a New Radio (NR) network. In some examples, the wireless communication system 100 can support enhanced broadband communication, ultra-reliable (e.g., mission-critical) communication, low-latency communication, communication with low-cost and low-complexity devices, or any combination thereof.

[0054] Base stations 105 can be dispersed over a geographical area to form a wireless communication system 100 and can be devices of different forms or with different capabilities. The base stations 105 and the UEs 115 can communicate wirelessly via one or more communication links 125. Each base station 105 can provide a coverage area 110 over which the UEs 115 and the base stations 105 can establish one or more communication links 125. The coverage area 110 can be an example of a geographical area over which the base stations 105 and the UEs 115 can support signal communication according to one or more radio access technologies.

[0055] The UEs 115 can be dispersed throughout the coverage area 110 of the wireless communication system 100, and each UE 115 can be stationary, or mobile, or both at different times. The UEs 115 can be devices of different forms or with different capabilities. Figure 1 Some example UEs 115 are illustrated. As Figure 1 shown, the UEs 115 described herein can be capable of communicating with various types of devices, such as other UEs 115, base stations 105, or network devices (e.g., core network nodes, relay devices, integrated access and backhaul (IAB) nodes, or other network devices).

[0056] The base stations 105 can communicate with the core network 130, or with each other, or with both. For example, the base stations 105 can be connected to the core network 130 via one or more backhaul links 120 (e.g., via S1, N2, N3, or other interfaces). The base stations 105 can communicate directly (e.g., directly between base stations 105) or indirectly (e.g., via the core network 130) with each other via the backhaul links 120 (e.g., via X2, Xn, or other interfaces), or both. In some examples, the backhaul links 120 can be or include one or more wireless links.

[0057] One or more of the base stations 105 described herein can include or can be referred to by those of ordinary skill in the art as: base transceiver stations, radio base stations, access points, radio transceivers, Node Bs, evolved Node Bs (eNBs), next generation Node Bs or Gigabit Node Bs (any of which can be referred to as gNBs), home Node Bs, home eNBs, or other suitable terms.

[0058] The UE 115 may include or may be referred to as a mobile device, wireless device, remote device, handheld device, or subscriber device, or some other suitable term, where, among other examples, a "device" may also be referred to as a unit, station, terminal, or client. The UE 115 may also include or may be referred to as a personal electronic device, such as a cellular phone, personal digital assistant (PDA), tablet computer, laptop computer, or personal computer. In some examples, the UE 115 may include or be referred to as a wireless local loop (WLL) station, Internet of Things (IoT) device, Internet of Everything (IoE) device, or machine type communication (MTC) device, etc., which may be implemented in various objects, such as appliances or vehicles, meters, etc.

[0059] The UE 115 described herein may be capable of communicating with various types of devices, such as other UE 115s that may sometimes act as relays, as well as base station 105 and network devices (including macro eNB or gNB, small cell eNB or gNB, or relay base stations), and other examples, as Figure 1 shown.

[0060] The UE 115 and the base station 105 may wirelessly communicate with each other on one or more carriers via one or more communication links 125. The term "carrier" may refer to a set of radio spectrum resources having a defined physical layer structure for supporting the communication link 125. For example, a carrier for the communication link 125 may include a portion (e.g., bandwidth part (BWP)) of a radio spectrum band that operates according to one or more physical layer channels for a given radio access technology (e.g., LTE, LTE-A, LTE-A Pro, NR). Each physical layer channel may carry acquisition signaling (e.g., synchronization signals, system information), control signaling for coordinating carrier operation, user data, or other signaling. The wireless communication system 100 may support communicating with the UE 115 using carrier aggregation or multi-carrier operation. According to a 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 with frequency division duplex (FDD) and time division duplex (TDD) component carriers.

[0061] In some examples (e.g., in a carrier aggregation configuration), a carrier may also have acquisition signaling or control signaling for coordinating the operation of other carriers. A carrier may be associated with a frequency channel (e.g., evolved universal mobile telecommunications system terrestrial radio access (E-UTRA) absolute radio frequency channel number (EARFCN)) and may be located according to a channel raster for discovery by the UE 115. A carrier may operate in an independent mode, where the UE 115 may perform initial acquisition and connection via the carrier, or a carrier may operate in a non-independent mode, where the connection uses a different carrier anchor (e.g., of the same or different radio access technology).

[0062] The communication link 125 shown in the wireless communication system 100 may include an uplink transmission from the UE 115 to the base station 105, or a downlink transmission from the base station 105 to the UE 115. A carrier may carry downlink or uplink communication (e.g., in FDD mode), or may be configured to carry both downlink and uplink communication (e.g., in TDD mode).

[0063] A carrier may be associated with a particular bandwidth of the radio spectrum, and in some examples, the carrier bandwidth may be referred to as the "system bandwidth" of the carrier or the wireless communication system 100. For example, the carrier bandwidth may be one of a plurality of determined bandwidths for a carrier of a particular radio access technology (e.g., 1.4, 3, 5, 10, 15, 20, 40, or 80 megahertz (MHz)). Devices of the wireless communication system 100 (e.g., the base station 105, the UE 115, or both) may have a hardware configuration that supports communication on a particular carrier bandwidth, or may be configured to support communication on one of a set of carrier bandwidths. In some examples, the wireless communication system 100 may include a base station 105 or a UE 115 that supports simultaneous communication via carriers associated with multiple carrier bandwidths. In some examples, each served UE 115 may be configured to operate on a portion (e.g., a subband, a BWP) or all of the carrier bandwidth.

[0064] The signal waveform transmitted on a carrier may be composed of multiple subcarriers (e.g., using a multi-carrier modulation (MCM) technique such as orthogonal frequency division multiplexing (OFDM) or discrete Fourier transform spread OFDM (DFT-S-OFDM)). In a system employing an MCM technique, a resource element may consist of a symbol period (e.g., the duration of a modulated symbol) and a subcarrier, where the symbol period and the subcarrier spacing are 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). Thus, the more resource elements received by the UE 115, and the higher the order of the modulation scheme, the higher the data rate of the UE 115 may be. Wireless communication resources may refer to a combination of radio spectrum resources, time resources, and space resources (e.g., spatial layers or beams), and using multiple spatial layers may further increase the data rate or data integrity of communication with the UE 115.

[0065] One or more parameter sets for a carrier may be supported, where the parameter sets may include subcarrier spacing (Δf) and cyclic prefix. A carrier may be divided into one or more BWPs having the same or different parameter sets. In some examples, UE 115 may be configured with multiple BWPs. In some examples, a single BWP of a carrier may be active at a given time, and the communication of UE 115 may be restricted to one or more active BWPs.

[0066] The time interval of base station 105 or UE 115 may be expressed as a multiple of a basic time unit, which may refer to T, for example. s = 1 / (Δf max ·N f ) second sampling period, where Δf max may represent the maximum supported subcarrier spacing, and N f may represent the maximum supported discrete Fourier transform (DFT) size. The time intervals of communication resources may be organized according to radio frames, each radio frame 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).

[0067] Each frame may include a plurality of consecutively numbered subframes or time slots, and each subframe or time slot may have the same duration. In some examples, a frame (e.g., in the time domain) may be divided into subframes, and each subframe may be further divided into a plurality of time slots. Alternatively, each frame may include a variable number of time slots, and the number of time slots may depend on the subcarrier spacing. Each time slot may include a plurality of symbol periods (e.g., depending on the length of the cyclic prefix appended to each symbol period). In some wireless communication systems 100, a time slot may be further divided into a plurality of mini-slots containing one or more symbols. In addition to the cyclic prefix, each symbol period may contain one or more (e.g., N f ) sampling periods. The duration of the symbol period may depend on the subcarrier spacing or the operating frequency band.

[0068] A subframe, time slot, mini-slot, or symbol may be the smallest scheduling unit of wireless communication system 100 (e.g., in the time domain), 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 wireless communication system 100 may be dynamically selected (e.g., in a burst of shortened TTIs (sTTIs)).

[0069] Physical channels can be multiplexed on a carrier according to various techniques. The physical control channel and the physical data channel can be multiplexed on a downlink carrier, for example, using one or more of time division multiplexing (TDM) techniques, frequency division multiplexing (FDM) techniques, or hybrid TDM-FDM techniques. The control region of the physical control channel (e.g., control resource set (CORESET)) can be defined by multiple symbol periods and can extend across the system bandwidth of the carrier or a subset of the system bandwidth. One or more control regions (e.g., CORESET) can be configured for the set of UEs 115. For example, one or more of the UEs 115 can monitor or search for a control region for control information according to one or more search space sets, and each search space set can 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 can refer to the number of control channel resources (e.g., control channel elements (CCE)) associated with the coded information of a control information format with a given payload size. The search space set can include a common search space set configured to send control information to multiple UEs 115 and a UE-specific search space set for sending control information to a specific UE 115.

[0070] Each base station 105 can provide communication coverage through one or more cells, such as macro cells, small cells, hotspots, or other types of cells, or any combination thereof. The term "cell" can refer to a logical communication entity for communicating with a base station 105 (e.g., via a carrier) and can be associated with an identifier (e.g., physical cell identifier (PCID), virtual cell identifier (VCID), or others) for distinguishing adjacent cells. In some examples, a cell can also refer to the geographical coverage area 110 or a part of the geographical coverage area 110 (e.g., a sector) on which the logical communication entity operates. Depending on various factors such as the capabilities of the base station 105, the scope of such cells can range from a smaller area (e.g., a structure, a subset of a structure) to a larger area. For example, a cell can be or include a building, a subset of a building, or an external space between or overlapping with the geographical coverage areas 110, and other examples.

[0071] Macro cells typically cover a relatively large geographical area (e.g., a radius of several kilometers) and can allow unrestricted access to UEs 115 having a service subscription with the network provider that supports the macro cell. Compared to macro cells, small cells can be associated with base stations 105 having lower power, and small cells can operate in the same or different (e.g., licensed, unlicensed) frequency bands as macro cells. Small cells can provide unrestricted access to UEs 115 having a service subscription with the network provider, or can provide restricted access to UEs 115 associated with the small cell (e.g., UEs 115 in a closed subscriber group (CSG), UEs 115 associated with users in a home or office). A base station 105 can support one or more cells and can also support communication on one or more cells using one or more component carriers.

[0072] In some examples, a carrier can support multiple cells and can be configured with different cell types according to different protocol types that can provide access to different types of devices (e.g., MTC, narrowband IoT (NB-IoT), enhanced mobile broadband (eMBB)).

[0073] In some examples, the base station 105 can be movable and thus provide communication coverage for a mobile geographical coverage area 110. In some examples, different geographical coverage areas 110 associated with different technologies can overlap, but different geographical coverage areas 110 can be supported by the same base station 105. In other examples, overlapping geographical coverage areas 110 associated with different technologies can be supported by different base stations 105. The wireless communication system 100 can include, for example, a heterogeneous network where different types of base stations 105 provide coverage for various geographical coverage areas 110 using the same or different radio access technologies.

[0074] The wireless communication system 100 can support synchronous or asynchronous operation. For synchronous operation, the base stations 105 can have similar frame timings, and transmissions from different base stations 105 can be approximately aligned in time. For asynchronous operation, the base stations 105 can have different frame timings, and in some examples, transmissions from different base stations 105 can be misaligned in time. The techniques described herein can be used for synchronous or asynchronous operation.

[0075] Some UEs 115 (such as MTC or IoT devices) can be low-cost or low-complexity devices and can provide automatic communication between machines (e.g., via machine-to-machine (M2M) communication). M2M communication or MTC can refer to data communication technologies that allow devices to communicate with each other or with the base station 105 without human intervention. In some examples, M2M communication or MTC can include communication from devices that integrate sensors or meters to measure or capture information and relay such information to a central server or application, which utilizes the information or presents the information to a person interacting with the application. Some UEs 115 can be designed to collect information or enable automatic behavior of machines or other devices. Examples of applications of MTC devices include smart metering, inventory monitoring, water level monitoring, device monitoring, healthcare monitoring, wildlife monitoring, weather and geological event monitoring, fleet management and tracking, remote security sensing, physical access control, and transaction-based business billing.

[0076] Some UEs 115 can be configured to operate in power-saving modes, such as half-duplex communication (e.g., a mode that supports one-way communication via transmission or reception but not simultaneous transmission and reception). In some examples, half-duplex communication can be performed at a reduced peak rate. Other power-saving techniques for UEs 115 include entering a power-saving deep sleep mode when not participating in active communication, operating on a limited bandwidth (e.g., according to narrowband communication), or a combination of these techniques. For example, some UEs 115 can be configured to operate using a narrowband protocol type that is associated with a defined portion or range within a carrier, within a guard band of the carrier, or outside the carrier (e.g., a set of subcarriers or resource blocks (RBs)).

[0077] The wireless communication system 100 can be configured to support ultra-reliable communication or low-latency communication or various combinations thereof. For example, the wireless communication system 100 can be configured to support ultra-reliable low-latency communication (URLLC) or mission-critical communication. The UE 115 can be designed to support ultra-reliable, low-latency, or critical functions (e.g., mission-critical functions). Ultra-reliable communication can include private communication or group communication and can be supported by one or more mission-critical services, such as mission-critical push-to-talk (MCPTT), mission-critical video (MCVideo), or mission-critical data (MCData). Support for mission-critical functions can include service prioritization, and mission-critical services can be used for public safety or general commercial applications. The terms ultra-reliable, low-latency, mission-critical, and ultra-reliable low-latency can be used interchangeably herein.

[0078] In some examples, the UE 115 may also be able to communicate directly with other UEs 115 via a device-to-device (D2D) communication link 135 (e.g., using peer-to-peer (P2P) or device-to-device (D2D) protocols). One or more of the UEs 115 that utilize D2D communication may be within the geographic coverage area 110 of the base station 105. Other UEs 115 in the group may be outside the geographic coverage area 110 of the base station 105, or otherwise unable to receive transmissions from the base station 105. In some examples, the group of UEs 115 that communicate via D2D communication may utilize a one-to-many (1:M) system in which each UE 115 transmits to each other UE 115 in the group. In some examples, the base station 105 facilitates resource scheduling for D2D communication. In other cases, D2D communication is performed between UEs 115 without the participation of the base station 105.

[0079] In some systems, the D2D communication link 135 may be an example of a communication channel between vehicles (e.g., UE 115), such as a sidelink communication channel. In some examples, vehicles may communicate using vehicle-to-everything (V2X) communication, vehicle-to-vehicle (V2V) communication, or some combination of these communications. Vehicles may signal information related to traffic conditions, signal scheduling, weather, safety, emergencies, or any other information related to the V2X system. In some examples, vehicles in a V2X system may communicate with roadside infrastructure, such as roadside units, or communicate with the network using vehicle-to-network (V2N) communication via one or more network nodes (e.g., base station 105), or communicate with both.

[0080] The core network 130 can provide user authentication, access authorization, tracking, Internet Protocol (IP) connectivity, and other access, routing, or mobility functions. The core network 130 can be an evolved packet core (EPC) or a 5G core (5GC), which can include at least one control plane entity that manages access and mobility (e.g., a mobility management entity (MME), an access and mobility management function (AMF)) and at least one user plane entity that routes or interconnects packets to an external network (e.g., a serving gateway (S-GW), a packet data network (PDN) gateway (P-GW), or a user plane function (UPF)). The control plane entity can manage non-access stratum (NAS) functions, such as the mobility, authentication, and bearer management of the UE 115 served by the base station 105 associated with the core network 130. User IP packets can be passed through the user plane entity, which can provide IP address allocation and other functions. The user plane entity can be connected to the network operator IP services 150. The operator IP services 150 can include access to the Internet, an intranet(s), an IP multimedia subsystem (IMS), or packet switched streaming services.

[0081] Some of the network devices (such as the base station 105) can include subcomponents such as the access network entity 140, which can be an example of an access node controller (ANC). Each access network entity 140 can communicate with the UE 115 through one or more other access network transmission entities 145, which can be referred to as radio heads, intelligent radio heads, or transmit / receive points (TRPs). Each access network transmission entity 145 can include one or more antenna panels. In some configurations, the various functions of each access network entity 140 or the base station 105 can be distributed across various network devices (e.g., radio heads and ANCs) or combined into a single network device (e.g., the base station 105).

[0082] The wireless communication system 100 can operate using one or more frequency bands generally in the range of 300 megahertz (MHz) to 3 gigahertz (GHz). Generally, the region from 300 MHz to 3 GHz is known as the ultra-high frequency (UHF) region or the decimeter band because the wavelength distances are from approximately 1 decimeter to 1 meter long. Building and environmental features may block or redirect UHF waves, but the waves can penetrate the structures of macrocells sufficiently to provide service to the UE 115 located indoors. Compared to transmissions at smaller frequencies and longer wavelengths using the high frequency (HF) or very high frequency (VHF) portions of the spectrum below 300 MHz, UHF wave transmissions can be associated with smaller antennas and shorter distances (e.g., less than 100 kilometers).

[0083] The wireless communication system 100 may also operate in the super high frequency (SHF) region using a frequency band from 3 GHz to 30 GHz (also known as the centimeter band), or in the extremely high frequency (EHF) region of the spectrum (e.g., from 30 GHz to 300 GHz) (also known as the millimeter band). In some examples, the wireless communication system 100 may support millimeter wave (mmW) communication between the UE 115 and the base station 105, and the EHF antennas of the respective devices may be even smaller and more closely spaced than UHF antennas. In some examples, this may facilitate the use of antenna arrays within the device. However, the propagation of EHF transmissions may suffer even greater atmospheric attenuation and shorter ranges compared to SHF or UHF transmissions. The techniques disclosed herein may be employed between transmissions using one or more different frequency regions, and the designated use of frequency bands across these frequency regions may vary by country or regulatory body.

[0084] The wireless communication system 100 may utilize both licensed and unlicensed radio frequency bands. For example, the wireless communication system 100 may employ licensed-assisted access (LAA), unlicensed LTE (LTE-U) radio access technology, or NR technology in an unlicensed band such as the 5 GHz industrial, scientific, and medical (ISM) band. When operating in an unlicensed radio frequency band, devices such as the base station 105 and the UE 115 may employ carrier sensing for collision detection and avoidance. In some examples, operation in the unlicensed band may be based on a carrier aggregation configuration along with component carriers operating in a licensed band (e.g., LAA). Operations in the unlicensed spectrum may include downlink transmissions, uplink transmissions, peer-to-peer (P2P) transmissions, or device-to-device (D2D) transmissions, etc.

[0085] The base station 105 or the UE 115 may be equipped with multiple antennas, which may be used to employ techniques such as transmit diversity, receive diversity, multiple-input multiple-output (MIMO) communication, or beamforming. The antennas of the base station 105 or the UE 115 may be located within one or more antenna arrays or antenna panels, which may support MIMO operation or transmit or receive beamforming. For example, one or more base station antennas or antenna arrays may be co-located at an antenna assembly, such as an antenna tower. In some examples, the antennas or antenna arrays associated with the base station 105 may be located at different geographical locations. The base station 105 may have an antenna array having multiple rows and columns of antenna ports that the base station 105 may use to support beamforming for communication with the UE 115. Similarly, the UE 115 may have one or more antenna arrays that may support various MIMO or beamforming operations. Additionally or alternatively, the antenna panel may support radio frequency beamforming for signals transmitted via the antenna ports.

[0086] The base station 105 or the UE 115 can use MIMO communication to utilize multipath signal propagation and improve spectral efficiency by transmitting or receiving multiple signals via different spatial layers. This technique can be referred to as spatial multiplexing. For example, multiple signals can be transmitted by a transmitting device via different antennas or different combinations of antennas. Similarly, multiple signals can be received by a receiving device via different antennas or different combinations of antennas. Each of the multiple signals can be referred to as a separate spatial stream and can carry bits associated with the same data stream (e.g., the same codeword) or different data streams (e.g., different codewords). Different spatial layers can be associated with different antenna ports for channel measurement and reporting. MIMO techniques include single-user MIMO (SU-MIMO), where multiple spatial layers are transmitted to the same receiving device, and multi-user MIMO (MU-MIMO), where multiple spatial layers are transmitted to multiple devices.

[0087] Beamforming (which can also be referred to as spatial filtering, directional transmission, or directional reception) is a signal processing technique that can be used at a transmitting device or a receiving device (e.g., the base station 105, the UE 115) to shape or steer an antenna beam (e.g., a transmit beam, a receive beam) along a spatial path between the transmitting device and the receiving device. Beamforming can be achieved by combining signals communicated via antenna elements in an antenna array such that signals propagating in a specific direction relative to the antenna array experience constructive interference while other signals experience destructive interference. The adjustment of the signals communicated via the antenna elements can include the transmitting device or the receiving device applying an offset, a phase shift, or both to the signals carried via the antenna elements associated with the device. The adjustment associated with each antenna element can be defined by a set of beamforming weights associated with a specific direction (e.g., relative to the antenna array of the transmitting device or the receiving device, or relative to some other direction).

[0088] The base station 105 or the UE 115 can use beam scanning techniques as part of beamforming operations. For example, the base station 105 can use multiple antennas or antenna arrays (e.g., antenna panels) to perform beamforming operations for directional communication with the UE 115. For example, some signals (e.g., synchronization signals, reference signals, beam selection signals, or other control signals) can be transmitted by the base station 105 multiple times in different directions, which can include transmitting the signals according to different sets of beamforming weights associated with different transmission directions. Transmissions in different beam directions can be used (e.g., by the base station 105 or a receiving device such as the UE 115) to identify the beam direction for subsequent transmissions and / or receptions by the base station 105.

[0089] Some signals, such as data signals associated with a particular receiving device, can be transmitted by the base station 105 in a single beam direction (e.g., the direction associated with a receiving device such as UE 115). In some examples, the beam direction associated with transmission along a single beam direction can be determined based on signals transmitted in one or more beam directions. For example, UE 115 can receive one or more signals transmitted by the base station 105 in different directions and can report to the base station 105 an indication of the signal received by UE 115 with the highest signal quality or other acceptable signal quality.

[0090] In some examples, transmissions of a device (e.g., base station 105 or UE 115) can be performed using multiple beam directions, and the device can use a combination of digital precoding or radio frequency beamforming to generate a combined beam for transmission (e.g., from base station 105 to UE 115). UE 115 can report feedback indicating precoding weights for one or more beam directions, and the feedback can correspond to a configured number of beams across the system bandwidth or one or more subbands. The base station 105 can transmit reference signals that can be precoded or not precoded (e.g., cell-specific reference signal (CRS), channel state information reference signal (CSI-RS)). UE 115 can provide feedback for beam selection, which can be a precoding matrix indicator (PMI) or codebook-based feedback (e.g., multi-panel type codebook, linear combination type codebook, port selection type codebook). Although these techniques are described with reference to signals transmitted by the base station 105 in one or more directions, UE 115 can employ similar techniques for transmitting signals multiple times in different directions (e.g., for identifying beam directions for subsequent transmission or reception by UE 115), or for transmitting signals in a single direction (e.g., for transmitting data to a receiving device).

[0091] When receiving various signals (such as synchronization signals, reference signals, beam selection signals, or other control signals) from base station 105, a receiving device (e.g., UE 115) may attempt multiple receiving configurations (e.g., directional listening). For example, the receiving device may attempt multiple receiving directions in the following ways: receiving via different antenna sub-arrays, processing received signals according to different antenna sub-arrays, receiving according to different sets of receiving beamforming weights (e.g., different directional listening weight sets) applied to signals received at multiple antenna elements of the antenna array, or processing received signals according to different sets of receiving beamforming weights applied to signals received at multiple antenna elements of the antenna array. Any of the above ways may be referred to as "listening" according to different receiving configurations or receiving directions. In some examples, the receiving device may use a single receiving configuration to receive along a single beam direction (e.g., when receiving a data signal). The single receiving configuration may be aligned in a beam direction determined based on listening according to different receiving 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).

[0092] Wireless communication system 100 may be a packet-based network operating according to a hierarchical protocol stack. In the user plane, communication at the packet data convergence protocol (PDCP) layer may be IP-based. The radio link control (RLC) layer may perform packet segmentation and reassembly for communication over logical channels. The medium access control (MAC) layer may perform priority handling and multiplex logical channels into transport channels. The MAC layer may also use error detection techniques, error correction techniques, or both to support retransmission at the MAC layer to improve link efficiency. In the control plane, the radio resource control (RRC) protocol layer may provide the establishment, configuration, and maintenance of an RRC connection between UE 115 and base station 105 or core network 130 that supports radio bearers for user plane data. At the physical layer, transport channels may be mapped to physical channels.

[0093] UE 115 and base station 105 may support retransmission of data to increase the likelihood of successful data reception. Hybrid automatic repeat request (HARQ) feedback is a technique for increasing the likelihood of correctly receiving data over communication link 125. HARQ may include a combination of error detection (e.g., using cyclic redundancy check (CRC)), forward error correction (FEC), and retransmission (e.g., automatic repeat request (ARQ)). HARQ may improve throughput at the MAC layer under adverse radio conditions (e.g., low signal-to-noise ratio conditions). In some examples, a device may support HARQ feedback for the same time slot, where the device may provide HARQ feedback for data received in a previous symbol in the particular time slot. In other cases, the device may provide HARQ feedback in a subsequent time slot or according to some other time interval.

[0094] UE 115 may measure the RSRP of transmissions from other UEs 115 in a time window and exclude transmission resources associated with RSRP measurements above an RSRP threshold. In some cases, where insufficient resources are identified, UE 115 may increase the RSRP and search for resources again based on the increased RSRP threshold; however, UE 115 may only increase the RSRP until a stop RSRP limit is reached. UE 115 may increase the RSRP based on a factor of an absolute value or incremental power value. Once the stop RSRP threshold is reached, UE 115 may modify the size of the time window, shift the time window, or reduce the number of retransmissions of sidelink messages to search for resources for transmitting sidelink messages. In some cases, base station 105-a may configure an exclusion range (i.e., resources excluded from consideration) or a configuration for increasing the RSRP threshold (e.g., a subset of values that the UE is able to use to increase the RSRP threshold) for UE 115.

[0095] Figure 2 FIG. illustrates an example of a wireless communication system 200 that supports sidelink candidate resource selection in accordance with aspects of the present disclosure. In some examples, wireless communication system 200 may implement aspects of wireless communication system 100. In some examples, wireless communication system 200 may include UEs 115-a, 115-b, 115-c, and base station 105-a, which may be examples of UEs 115 and base station 105 as Figure 1 described. One or more of the UEs 115 may communicate with base station 105-a using corresponding access links 205. In this example, base station 105-a may communicate with UE 115-b via access link 205.

[0096] In this example, UEs 115-a, 115-b, and 115-c can be supported by base station 105-a or can be members of a sidelink communication group, and the members of the group can communicate with other members of the group via sidelink 210 to provide data or other information. In this example, UE 115-a can communicate with UE 115-b via sidelink 210-a, and UE 115-a can communicate with UE 115-c via sidelink 210-b.

[0097] UEs 115-a, 115-b, and 115-c can determine time-frequency resources (e.g., based on a distributed channel access mechanism in which each UE 115 adjusts its channel access rate based on data packet collisions) to communicate with each other via sidelink 210. Before transmitting a transmission, UE 115-a can select a set of available resources for the transmission. UE 115-a can determine the available (e.g., candidate) resources by excluding the resources utilized by other UEs 115 (e.g., UEs 115-b and 115-c). For example, UEs 115-b and 115-c can transmit SCI 215 to UE 115-a. SCI 215 can indicate the time-frequency resources (time slots, mini-slots, subframes, channels, subcarriers, sub-channels, etc.) allocated for ongoing transmissions or the reservation of resources for future transmissions. UE 115-a can decode SCI 215 to identify the reserved resources and exclude those reserved resources from the set of available resources that are available for selection for sidelink communication. Additionally or alternatively, UE 115-a can determine the excluded resources based on the location information of UE 115-b or UE 115-c that may be included in control information (e.g., SCI) sent by UE 115-b, UE 115-c, base station 105-a, or other network devices.

[0098] UE 115-a can identify candidate resources within a resource selection window and select resources for transmission or retransmission. In some examples, UE 115-a can determine which resources are reserved by measuring the signal strength (e.g., RSRP, RSRQ, etc.) of reference signals from UE 115-b or UE 115-c. UE 115-a can measure the RSRP associated with SCI 215 from UEs 115-b and 115-c within a time window. If the RSRP (e.g., layer 1 sidelink RSRP) measurement is higher than an RSRP threshold, the resource can be excluded as a candidate. An RSRP measurement higher than the RSRP threshold can indicate that the transmission is from a neighboring UE. An RSRP measurement lower than the RSRP threshold can indicate that the transmission is from a farther UE, or that the resource is a candidate resource.

[0099] The RSRP threshold can be a function of the priority of the sidelink transmission indicated in the received SCI 215 and the priority of the transmission for which the UE 115-a is selecting resources. The initial RSRP threshold can be preconfigured for each combination of the priority indication associated with the resources indicated in the SCI 215 and the priority of the transmission in the UE 115-a that is selecting resources.

[0100] In some examples, the UE 115-a can increase the RSRP threshold (e.g., increase by a certain number of decibels (dB)) until the ratio of the identified candidate resources to the total number of resources in the resource selection window is greater than a determined percentage value (e.g., 10%, 20%, 30%). If the ratio is less than the determined percentage value, the UE 115-a can increase the RSRP threshold by a certain number of dB (e.g., based on an absolute value, factor, or percentage above the initial RSRP threshold) and repeat the candidate resource selection process. The UE 115-a can repeat the candidate resource selection process until the ratio of the determined candidate resources to the total number of resources is identified.

[0101] Depending on the size of the selection window, the UE 115-a can increase the RSRP threshold to a value that causes a transmission from the UE 115-a to conflict with transmissions from the UE 115-b and UE 115-c. A conflict can occur because the UE 115-a uses resources reserved by the UE 115-b and UE 115-c, but the RSRP of these reserved resources is lower than the increased RSRP threshold. Thus, the UE 115-a can identify these reserved resources as available, which results in conflicts and degraded performance. The techniques herein can limit the UE 115-a from increasing the RSRP threshold above a stop RSRP threshold during resource selection and can be based on the selection window length, the priority of the transmission, or the PDB of the sidelink message to be scheduled for transmission by the UE 115-a.

[0102] In accordance with aspects of the present disclosure, UE 115-a may determine a selection window length to determine candidate resources for transmission. When measuring the RSRP associated with the SCI 215 from UE 115-b and UE 115-c, the RSRP threshold may include a lower threshold (e.g., an initial RSRP threshold) and an upper threshold (e.g., a stop RSRP threshold). The stop RSRP threshold may be preconfigured in UE 115-a, UE 115-b, and UE 115-c by the network (e.g., base station 105-a). Additionally or alternatively, base station 105-a may indicate an exclusion range of the RSRP threshold in control information, and UE 115-a, UE 115-b, and UE 115-c may implement the exclusion range. When selecting candidate resources and excluding reserved resources, UE 115-a may start with the initial RSRP threshold and increase the RSRP threshold by a value or factor of Y dB (e.g., 3 dB, 2 dB, 5 dB) until reaching a ratio of the identified candidate resources to the total number of resources (e.g., 20% of the total number of resources are idle or candidate resources) or reaching or exceeding the stop RSRP threshold (e.g., 10 dB, 12 dB).

[0103] In some cases, the stop RSRP threshold may be a function of the priority of the transmission, the PDB of the transmission, or the number of retransmissions. In a first example, if the transmission has a high priority, UE 115-a may increase the stop RSRP threshold to ensure the transmission is delivered. In a second example, if the transmission has a high PDB, UE 115-a may decrease the stop RSRP threshold because UE 115-a must determine the amount of time for candidate resources for the transmission. In a third example, if there are a large number of retransmissions, UE 115-a may decrease the stop RSRP threshold to ensure a portion of the retransmissions are successfully delivered and avoid network congestion.

[0104] In some cases, the initial RSRP threshold and the stop RSRP threshold may be preconfigured in UE 115-a by the network and depend on the priorities of the transmissions of UE 115-a, UE 115-b, and UE 115-c. The priorities may include the priority of the transmission of UE 115-a itself for which resources are being selected and the priorities of the transmissions received from UE 115-b and UE 115-c as indicated in the SCI 215 that identifies the reserved resources. In a first example, if UE 115-b has a transmission with a higher priority than UE 115-a, UE 115-b may transmit on the resource. In a second example, if UE 115-a has a transmission with a higher priority than UE 115-c, UE 115-a may select and transmit on a resource reserved by UE 115-c.

[0105] Figure 3 FIG. illustrates an example of a resource selection scheme 300 that supports sidelink candidate resource selection in accordance with aspects of the present disclosure. In some examples, the resource selection scheme 300 may include UEs 115-d, 115-e, 115-f, which may be examples of the UE 115 described with reference Figure 1 and Figure 2 above.

[0106] UE 115-f may identify candidate resources 320 within a resource selection window 305 and select a resource for transmission. In some examples, UE 115-f may determine which resources are reserved by UE 115-d (e.g., resource 310) and UE 115-e (e.g., resource 315) by measuring the RSRP associated with the SCI from UE 115-d or UE 115-e within the resource selection window 305. If the RSRP measurement is above an RSRP threshold, the resource may be excluded as a candidate.

[0107] UE 115-f may determine a window length to determine candidate resources for transmission. The resource selection window 305 may start at time T 1 (or n+T 1 ) and end at time T 2 (or n+T 2 ). The duration of the resource selection window 305 may be a function of the PDB or transmission priority. T 1 and T 2 may be UE-implemented or pre-configured by the network. In some cases, UE 115-f may increase the RSRP threshold until it exceeds or reaches a stop RSRP threshold. UE 115-f may adjust (e.g., increase) the duration of the selection window 305 by increasing the end time T 2 to time T 3 , resulting in a selection window 325. UE 115-f may determine candidate resources by measuring the RSRP of transmissions from UE 115-d or 115-e within the selection window 325.

[0108] In some cases, UE 115-f may adjust the duration of the selection window 305 by increasing the start time T 1 and the end time T 2 . Adjusting the start and end times of the selection window 305 may slide the selection window such that it has a start time of T 2 (e.g., n+T 2 ) and an end time of T 4 (e.g., n+2*T 2 ), resulting in a selection window 330.

[0109] UE 115-f may increase the RSRP threshold until the ratio of the identified candidate resources to the total number of resources in the resource selection window 305 is greater than a determined percentage value. In some cases, if the ratio of the identified candidate resources to the total number of resources in the resource selection window 305 is less than the determined percentage value, UE 115-f may adjust the resource selection window by adjusting the start and end times (e.g., adjusting to the duration of resource selection window 325 or 330), rather than increasing the RSRP threshold. After adjusting the resource selection window, UE 115-a may measure the transmitted RSRP and increase the RSRP threshold until the ratio of the identified candidate resources to the total number of resources in the adjusted resource selection window is greater than the determined percentage value.

[0110] The duration of the resource selection window may increase according to the PDB or the number of retransmissions. For example, UE 115-f may reduce the number of retransmissions, which will result in UE 115-f transmitting fewer transmissions in the selection window of the PDB. With fewer retransmissions, UE 115-f may identify candidate resources without conflicting with other transmissions. Thus, congestion control may be based on resource allocation.

[0111] Figure 4 An example of a processing flow 400 that supports sidelink candidate resource selection in accordance with aspects of the present disclosure is illustrated. In some examples, the processing flow 400 may implement aspects of the wireless communication system 100. In some examples, the processing flow 400 may include UE 115-g, UE 115-h, and base station 105-b, which may be examples of the UE 115 and base station 105 as Figure 1 described.

[0112] At 405, base station 105-b may establish a communication link (e.g., an access link) with UE 115-g that communicates with UE 115-h via a sidelink communication link.

[0113] At 410, base station 105-b may determine a configuration for candidate resource selection for sidelink messages from UE 115-g to UE 115-h, which may be based on an initial power threshold (e.g., an initial RSRP threshold) and a stop power threshold (e.g., a stop RSRP threshold). In some examples, the configuration may indicate an increase in the power threshold for determining a candidate resource set for sidelink messages. The increase in the power threshold may be based on an absolute value, a factor of an incremental value, the number of retransmissions associated with the sidelink message, the priority of the sidelink message, the PDB associated with the sidelink message, the priority of the scheduled transmissions of at least one neighboring UE (e.g., UE 115-h), or any combination thereof.

[0114] At 415, base station 105-b may transmit a configuration for candidate resource selection for sidelink messages to UE 115-g. In some examples, base station 105-b may transmit an indication via a control channel message to UE 115-g for determining an exclusion range for a candidate resource set for sidelink messages, where the exclusion range specifies resources to be excluded from the candidate resource set.

[0115] At 420, UE 115-g may determine a time window for resource selection for transmission of a sidelink message from UE 115-g to UE 115-h. The time window may be based on the PDB of the sidelink message or the number of retransmissions associated with the sidelink message. In some examples, UE 115-g may increase the size of the time window for selecting resources for transmission of the sidelink message.

[0116] At 425, UE 115-g may determine the RSRP of a reference signal from at least one neighboring UE (e.g., UE 115-h). UE 115-g may determine that the RSRP of the reference signal is higher than an initial power threshold and increase a power threshold for determining a candidate resource set, where the power threshold is between the initial power threshold and a stop power threshold. In some cases, UE 115-g may increase the power threshold based on an absolute value, a factor of an incremental value, the number of retransmissions associated with the sidelink message, the priority of the sidelink message, the PDB associated with the sidelink message, the priority of a scheduled transmission of at least one neighboring UE, or any combination thereof. Additionally or alternatively, UE 115-g may inhibit increasing the power threshold to exceed the stop power threshold.

[0117] In some cases, UE 115-g may determine that the RSRP of a reference signal from a neighboring UE is higher than the stop power threshold, where the size of the time window is increased based on the determination that the RSRP is higher than the stop power threshold. In other cases, UE 115-g may move the time window from a first start time to a second start time after the first start time. UE 115-g may determine that the RSRP is higher than the stop power threshold, where the time window is moved at least in part based on the determination that the RSRP is higher than the stop power threshold.

[0118] In some cases, UE 115-g may determine that the RSRP of a reference signal from at least one neighboring UE is higher than the initial power threshold. UE 115-g may reduce the number of retransmissions associated with the sidelink message and increase the size of the time window based on reducing the number of retransmissions. UE 115-g may receive a configuration from base station 105-b for increasing the power threshold for determining a candidate resource set and increase the power threshold.

[0119] At 430, the UE 115-g may determine a candidate resource set for transmission of a sidelink message within a time window. The candidate resource set may correspond to a threshold percentage of the total resources within the time window that is available for resource selection based on an initial power threshold, a stop power threshold, and power measurements associated with at least one neighboring UE. In some examples, the UE 115-g may determine the candidate resource set based on an increased size of the time window, a moving time window, a configuration received from the base station 105-b for increasing the power threshold, or an exclusion range, where the candidate resource set excludes the resources specified by the exclusion range. In other examples, the UE 115-g may determine the candidate resource set based on RSRP, an initial power threshold, and a stop power threshold. The UE 115-g may determine the resource set after increasing the power threshold.

[0120] At 435, the UE 115-g may select a resource from the candidate resource set for transmission of a sidelink message.

[0121] At 440, the UE 115- may transmit a sidelink message to the UE 115-h via the selected resource.

[0122] Figure 5 FIG. 500 is a block diagram of a device 505 that supports sidelink candidate resource selection in accordance with aspects of the present disclosure. The device 505 may be an example of aspects of the UE 115 described herein. The device 505 may include a receiver 510, a communication manager 515, and a transmitter 520. The device 505 may also include a processor. Each of these components may communicate with one another (e.g., via one or more buses).

[0123] The receiver 510 may receive information such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information related to sidelink candidate resource selection, etc.). The information may be passed to other components of the device 505. The receiver 510 may be an example of aspects of the transceiver 820 described with reference to Figure 8 The receiver 510 may utilize a single antenna or an antenna array.

[0124] The communication manager 515 may determine a time window for resource selection for transmission of a sidelink message from a first UE to a second UE, determine a candidate resource set for transmission of the sidelink message within the time window, the candidate resource set corresponding to a threshold percentage of the total resources within the time window that is available for resource selection based on an initial power threshold, a stop power threshold, and power measurements associated with at least one neighboring UE, select a resource from the candidate resource set for transmission of the sidelink message, and transmit the sidelink message to the second UE via the selected resource. The communication manager 515 may be an example of aspects of the communication manager 810 described herein.

[0125] The communication manager 515 or its sub-components can be implemented in hardware, code run by a processor (e.g., software or firmware), or any combination thereof. If implemented in code run by a processor, the functions of the communication manager 515 or its sub-components can be performed by a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described in this disclosure.

[0126] The communication manager 515 or its sub-components can be physically located at various positions, including being distributed such that portions of the functions are implemented by one or more physical components at different physical locations. In some examples, in accordance with various aspects of the present disclosure, the communication manager 515 or its sub-components can be separate and distinct components. In some examples, in accordance with various aspects of the present disclosure, the communication manager 515 or its sub-components can be combined with one or more other hardware components, including but not limited to input / output (I / O) components, transceivers, network servers, another computing device, one or more other components described in this disclosure, or combinations thereof.

[0127] The transmitter 520 can send signals generated by other components of the device 505. In some examples, the transmitter 520 can be collocated with the receiver 510 in a transceiver module. For example, the transmitter 520 can be an example of aspects of the transceiver 820 described with reference to Figure 8 The transmitter 520 can utilize a single antenna or an antenna array.

[0128] In some examples, the communication manager 515 can be implemented as an integrated circuit or chipset for a mobile device modem, and the receiver 510 and transmitter 520 can be implemented as analog components (e.g., amplifiers, filters, antennas) coupled to the mobile device modem to enable wireless transmission and reception on one or more frequency bands.

[0129] The communication manager 515 as described herein can be implemented to achieve one or more potential advantages. One implementation can allow the device 505 to determine candidate resources for transmitting sidelink messages. Determining candidate resources prior to transmission can increase reliability and reduce latency during sidelink transmissions.

[0130] Based on the techniques for selecting candidate resources for sidelink communication as described herein, of the UE 115 (e.g., the control receiver 510, the transmitter 520, or as referenced Figure 8The processor (of the described transceiver 820) can increase reliability, reduce collisions, and reduce signaling overhead in sidelink communication.

[0131] Figure 6 FIG. 600 is a block diagram of a device 605 that supports sidelink candidate resource selection in accordance with aspects of the present disclosure. The device 605 may be an example of aspects of the device 505 or UE 115 described herein. The device 605 may include a receiver 610, a communication manager 615, and a transmitter 635. The device 605 may also include a processor. Each of these components may communicate with one another (e.g., via one or more buses).

[0132] The receiver 610 may receive information such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information related to sidelink candidate resource selection, etc.). The information may be passed to other components of the device 605. The receiver 610 may be an example of aspects of the transceiver 820 described with reference to Figure 8 The receiver 610 may utilize a single antenna or an antenna array.

[0133] The communication manager 615 may be an example of aspects of the communication manager 515 described herein. The communication manager 615 may include a time window component 620, a candidate resource selector 625, and a sidelink message transmitter 630. The communication manager 615 may be an example of aspects of the communication manager 810 described herein.

[0134] The time window component 620 may determine a time window for resource selection for the transmission of a sidelink message from a first UE to a second UE.

[0135] The candidate resource selector 625 may determine a set of candidate resources for the transmission of a sidelink message within the time window, the set of candidate resources corresponding to a threshold percentage of the total resources within the time window that are available for resource selection based on an initial power threshold, a stop power threshold, and a power measurement associated with at least one neighboring UE, and select a resource for the transmission of the sidelink message from the set of candidate resources.

[0136] The sidelink message transmitter 630 may transmit a sidelink message to the second UE via the selected resource.

[0137] The transmitter 635 may transmit signals generated by other components of the device 605. In some examples, the transmitter 635 may be collocated with the receiver 610 in a transceiver module. For example, the transmitter 635 may be an example of aspects of the transceiver 820 described with reference to Figure 8 The transmitter 635 may utilize a single antenna or an antenna array.

[0138] In some examples, the communication manager 615 can be implemented as an integrated circuit or chipset for a mobile device modem, and the receiver 610 and transmitter 635 can be implemented as analog components (e.g., amplifiers, filters, antennas) coupled to the mobile device modem to enable wireless transmission and reception on one or more frequency bands.

[0139] The communication manager 615 as described herein can be implemented to realize one or more potential advantages. One implementation can allow the device 605 to determine candidate resources for transmitting sidelink messages. Determining candidate resources prior to transmission can increase reliability and reduce latency during sidelink transmissions.

[0140] Based on the techniques for selecting candidate resources for sidelink communication as described herein, the processor of the UE 115 (e.g., controlling the receiver 610, transmitter 635, or transceiver 820 as described with reference to Figure 8 can increase reliability, reduce collisions, and reduce signaling overhead in sidelink communication.

[0141] Figure 7 FIG. 700 is a block diagram of a communication manager 705 that supports sidelink candidate resource selection in accordance with aspects of the present disclosure. The communication manager 705 can be an example of aspects of the communication manager 515, communication manager 615, or communication manager 810 described herein. The communication manager 705 can include a time window component 710, a candidate resource selector 715, a sidelink message transmitter 720, an RSRP component 725, a power threshold component 730, a configuration component 735, and a candidate resource component 740. Each of these modules can communicate with each other directly or indirectly (e.g., via one or more buses).

[0142] The time window component 710 can determine a time window for resource selection for the transmission of a sidelink message from a first UE to a second UE.

[0143] In some examples, the time window component 710 can increase the size of the time window for selecting resources for the transmission of a sidelink message.

[0144] In some examples, the time window component 710 can move the time window from a first start time to a second start time after the first start time.

[0145] In some examples, the time window component 710 can determine the number of retransmissions associated with a sidelink message.

[0146] In some examples, the time window component 710 can determine the size of the time window based on the number of retransmissions.

[0147] In some examples, the time window component 710 may increase the size of the time window based on reducing the number of retransmissions.

[0148] In some examples, the time window component 710 may determine the time window based on the packet delay budget of the sidelink message.

[0149] The candidate resource selector 715 may determine a set of candidate resources for the transmission of the sidelink message within the time window, and the set of candidate resources corresponds to a threshold percentage of the total resources within the time window that is available for resource selection based on an initial power threshold, a stop power threshold, and a power measurement associated with at least one neighboring UE.

[0150] In some examples, the candidate resource selector 715 may select a resource for the transmission of the sidelink message from the set of candidate resources.

[0151] In some examples, the candidate resource selector 715 may determine the set of candidate resources based on RSRP, an initial power threshold, and a stop power threshold.

[0152] In some examples, the candidate resource selector 715 may determine the set of candidate resources based on RSRP and a power threshold.

[0153] In some examples, the candidate resource selector 715 may determine the set of candidate resources based on the increased size of the time window.

[0154] In some examples, the candidate resource selector 715 may determine the set of candidate resources based on a moving time window.

[0155] In some examples, the candidate resource selector 715 may receive an indication of an exclusion range for resource selection for the transmission of the sidelink message.

[0156] In some examples, the candidate resource selector 715 may determine the set of candidate resources based on the exclusion range, where the set of candidate resources excludes the resources specified by the exclusion range.

[0157] In some cases, the indication is received from the base station via a control channel message.

[0158] The sidelink message transmitter 720 may transmit the sidelink message to the second UE via the selected resource.

[0159] The RSRP component 725 may determine the reference signal received power (RSRP) of the reference signal from at least one neighboring UE.

[0160] In some examples, the RSRP component 725 may determine that the RSRP of the reference signal is higher than the initial power threshold.

[0161] In some examples, the RSRP component 725 may determine that the RSRP is higher than a stop power threshold, and based on the determination that the RSRP is higher than the stop power threshold, increase the size of the time window.

[0162] In some examples, the RSRP component 725 may determine that the RSRP is higher than a stop power threshold, and based on the determination that the RSRP is higher than the stop power threshold, move the time window.

[0163] In some examples, the RSRP component 725 may determine that the reference signal received power (RSRP) of a reference signal from at least one neighboring UE is higher than an initial power threshold.

[0164] The power threshold component 730 may increase the power threshold for determining a candidate resource set, where the power threshold is between the initial power threshold and the stop power threshold.

[0165] In some examples, the power threshold component 730 may be based on an absolute value, a factor of an incremental value, the number of retransmissions associated with a sidelink message, the priority of the sidelink message, the packet delay budget (PDB) associated with the sidelink message, the priority of a scheduled transmission of at least one neighboring UE, or any combination thereof.

[0166] In some examples, the power threshold component 730 may inhibit increasing the power threshold beyond the stop power threshold.

[0167] In some examples, the power threshold component 730 may receive a configuration for increasing the power threshold for determining a candidate resource set.

[0168] In some examples, the power threshold component 730 may increase the power threshold for determining a candidate resource set according to the configuration.

[0169] The configuration component 735 may reduce the number of retransmissions associated with a sidelink message.

[0170] In some cases, the configuration is received from the base station via a control channel message.

[0171] The candidate resource component 740 may determine a candidate resource set from the time window based on the increased size.

[0172] In some examples, the candidate resource component 740 may determine a candidate resource set based on a configuration.

[0173] In some examples, the candidate resource component 740 may determine a candidate resource set after increasing the power threshold.

[0174] Figure 8FIG. shows a system 800 including a device 805 that supports sidelink candidate resource selection in accordance with aspects of the present disclosure. The device 805 may be an example of, or include components of, the device 505, the device 605, or the UE 115 described herein. The device 805 may include components for two-way voice and data communication, including components for sending and receiving communications. The device 805 includes a communication manager 810, an I / O controller 815, a transceiver 820, an antenna 825, a memory 830, and a processor 840. These components may communicate electronically via one or more buses (e.g., bus 845).

[0175] The communication manager 810 may determine a time window for resource selection for the transmission of a sidelink message from a first UE to a second UE, determine a set of candidate resources for the transmission of the sidelink message within the time window, the candidate resource set corresponding to a threshold percentage of the total resources within the time window that is available for resource selection based on an initial power threshold, a stop power threshold, and power measurements associated with at least one neighboring UE, select a resource for the transmission of the sidelink message from the candidate resource set, and transmit the sidelink message to the second UE via the selected resource.

[0176] The I / O controller 815 may manage the input and output signals of the device 805. The I / O controller 815 may also manage peripheral devices not integrated into the device 805. In some cases, the I / O controller 815 may represent a physical connection or port to an external peripheral device. In some cases, the I / O controller 815 may utilize an operating system such as or another known operating system. In other cases, the I / O controller 815 may represent a modem, keyboard, mouse, touch screen, or similar device, or may interact with these devices. In some cases, the I / O controller 815 may be implemented as part of a processor. In some cases, a user may interact with the device 805 via the I / O controller 815 or via hardware components controlled by the I / O controller 815.

[0177] The transceiver 820 may communicate bidirectionally via one or more antennas, wired or wireless links as described herein. For example, the transceiver 820 may represent a wireless transceiver and may communicate bidirectionally with another wireless transceiver. The transceiver 820 may also include a modem to modulate packets and provide the modulated packets to the antenna for transmission, and to demodulate packets received from the antenna.

[0178] In some cases, a wireless device may include a single antenna 825. However, in some cases, the device may have more than one antenna 825 capable of simultaneously transmitting or receiving multiple wireless transmissions.

[0179] The memory 830 may include RAM and ROM. The memory 830 may store computer-readable, computer-executable code 835, including instructions that, when executed, cause the processor to perform the various functions described herein. In some cases, the memory 830 may further contain, among other things, a basic input / output system (BIOS), which may control basic hardware or software operations such as interactions with peripheral components or devices.

[0180] The processor 840 may include intelligent hardware devices (e.g., a general-purpose processor, DSP, CPU, microcontroller, ASIC, FPGA, programmable logic device, discrete gate or transistor logic components, discrete hardware components, or any combination thereof). In some cases, the processor 840 may be configured to operate a memory array using a memory controller. In other cases, the memory controller may be integrated into the processor 840. The processor 840 may be configured to run computer-readable instructions stored in a memory (e.g., the memory 830) to cause the device 805 to perform various functions (e.g., functions or tasks supporting sidelink candidate resource selection).

[0181] The code 835 may include instructions for implementing aspects of the present disclosure, including instructions for supporting wireless communications. The code 835 may be stored in a non-transitory computer-readable medium such as system memory or other types of memory. In some cases, the code 835 may not be directly executable by the processor 840, but may, for example, cause a computer to perform the functions described herein when compiled and run.

[0182] Figure 9 Block diagram 900 of a device 905 supporting sidelink candidate resource selection in accordance with aspects of the present disclosure is shown. The device 905 may be an example of aspects of the base station 105 described herein. The device 905 may include a receiver 910, a communication manager 915, and a transmitter 920. The device 905 may further include a processor. Each of these components may communicate with each other (e.g., via one or more buses).

[0183] The receiver 910 may receive information such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information related to sidelink candidate resource selection, etc.). The information may be passed to other components of the device 905. The receiver 910 may be an example of aspects of the transceiver 1220 described with reference to Figure 12 The receiver 910 may utilize a single antenna or an antenna array.

[0184] The communication manager 915 may establish a communication link with a first UE that communicates with a second UE via a sidelink communication link, transmit an indication of a configuration to the first UE, and determine a configuration for candidate resource selection for sidelink messages from the first UE to the second UE, the configuration being based on an initial power threshold and a stop power threshold. The communication manager 915 may be an example of aspects of the communication manager 1210 described herein.

[0185] The communication manager 915 or its subcomponents may be implemented in hardware, code run by a processor (e.g., software or firmware), or any combination thereof. If implemented in code run by a processor, the functions of the communication manager 915 or its subcomponents may be performed by a general-purpose processor, a DSP, an application-specific integrated circuit (ASIC), an FPGA, or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described in this disclosure.

[0186] The communication manager 915 or its subcomponents may physically be located in various positions, including being distributed such that portions of the functionality are implemented by one or more physical components in different physical locations. In some examples, in accordance with aspects of the present disclosure, the communication manager 915 or its subcomponents may be separate and distinct components. In some examples, in accordance with aspects of the present disclosure, the communication manager 915 or its subcomponents may be combined with one or more other hardware components, including but not limited to input / output (I / O) components, transceivers, network servers, another computing device, one or more other components described in this disclosure, or combinations thereof.

[0187] The transmitter 920 may send signals generated by other components of the device 905. In some examples, the transmitter 920 may be collocated with the receiver 910 in a transceiver module. For example, the transmitter 920 may be an example of aspects of the transceiver 1220 described with reference to Figure 12 The transmitter 920 may utilize a single antenna or an antenna array.

[0188] Figure 10 Block diagram 1000 of a device 1005 supporting sidelink candidate resource selection in accordance with aspects of the present disclosure is shown. The device 1005 may be an example of aspects of the device 905 or the base station 105 described herein. The device 1005 may include a receiver 1010, a communication manager 1015, and a transmitter 1030. The device 1005 may also include a processor. Each of these components may communicate with one another (e.g., via one or more buses).

[0189] The receiver 1010 may receive information such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information related to sidelink candidate resource selection, etc.). The information may be passed to other components of the device 1005. The receiver 1010 may be an example of aspects of the transceiver 1220 described with reference to Figure 12 The receiver 1010 may utilize a single antenna or an antenna array.

[0190] The communication manager 1015 may be an example of aspects of the communication manager 915 described herein. The communication manager 1015 may include a communication link manager 1020 and a candidate resource manager 1025. The communication manager 1015 may be an example of aspects of the communication manager 1210 described herein.

[0191] The communication link manager 1020 may establish a communication link with a first UE communicating with a second UE via a sidelink communication link and transmit an indication of the configuration to the first UE.

[0192] The candidate resource manager 1025 may determine a configuration for candidate resource selection for sidelink messages from the first UE to the second UE, based on an initial power threshold and a stop power threshold.

[0193] The transmitter 1030 may transmit signals generated by other components of the device 1005. In some examples, the transmitter 1030 may be collocated with the receiver 1010 in a transceiver module. For example, the transmitter 1030 may be an example of aspects of the transceiver 1220 described with reference to Figure 12 The transmitter 1030 may use a single antenna or an antenna array.

[0194] Figure 11 FIG. 1100 shows a block diagram 1100 of a communication manager 1105 that supports sidelink candidate resource selection in accordance with aspects of the present disclosure. The communication manager 1105 may be an example of aspects of the communication manager 915, the communication manager 1015, or the communication manager 1210 described herein. The communication manager 1105 may include a communication link manager 1110 and a candidate resource manager 1115. Each of these modules may communicate directly or indirectly with each other (e.g., via one or more buses).

[0195] The communication link manager 1110 may establish a communication link with a first UE communicating with a second UE via a sidelink communication link.

[0196] In some examples, the communication link manager 1110 may transmit an indication of the configuration to the first UE.

[0197] The candidate resource manager 1115 may determine a configuration for candidate resource selection for sidelink messages from a first UE to a second UE, the configuration being based on an initial power threshold and a stop power threshold.

[0198] In some examples, the candidate resource manager 1115 may transmit an indication for determining an exclusion range for a candidate resource set for sidelink messages, where the exclusion range specifies resources to be excluded from the candidate resource set.

[0199] In some cases, the configuration indicates an increase in a power threshold for determining a candidate resource set for sidelink messages.

[0200] In some cases, the increase in the power threshold is based on an absolute value, a factor of an incremental value, the number of retransmissions associated with the sidelink message, the priority of the sidelink message, a packet delay budget (PDB) associated with the sidelink message, the priority of a scheduled transmission of at least one neighboring UE, or any combination thereof.

[0201] In some cases, the indication is transmitted via a control channel message.

[0202] Figure 12 FIG. shows a system 1200 including a device 1205 supporting sidelink candidate resource selection in accordance with aspects of the present disclosure. The device 1205 may be an example of or include components of the device 905, the device 1005, or the base station 105 described herein. The device 1205 may include components for two-way voice and data communication, including components for sending and receiving communications. The device 1205 includes a communication manager 1210, a network communication manager 1215, a transceiver 1220, an antenna 1225, a memory 1230, a processor 1240, and an inter-station communication manager 1245. These components may communicate electronically via one or more buses (e.g., bus 1250).

[0203] The communication manager 1210 may establish a communication link with a first UE communicating with a second UE via a sidelink communication link, transmit an indication of the configuration to the first UE, and determine a configuration for candidate resource selection for sidelink messages from the first UE to the second UE, the configuration being based on an initial power threshold and a stop power threshold.

[0204] The network communication manager 1215 may manage communication with the core network (e.g., via one or more wired backhaul links). For example, the network communication manager 1215 may manage the delivery of data communication of client devices such as one or more UEs 115.

[0205] The transceiver 1220 can perform two-way communication via one or more antennas, wired or wireless links as described herein. For example, the transceiver 1220 can represent a wireless transceiver and can communicate bidirectionally with another wireless transceiver. The transceiver 1220 can also include a modem for modulating packets and providing the modulated packets to the antenna for transmission, and for demodulating packets received from the antenna.

[0206] In some cases, the wireless device can include a single antenna 1225. However, in some cases, the device may have multiple antennas 1225 capable of concurrently transmitting or receiving multiple wireless transmissions.

[0207] The memory 1230 can include RAM, ROM, or a combination thereof. The memory 1230 can store computer-readable code 1235 that includes instructions that, when executed by a processor (e.g., processor 1240), cause the device to perform the various functions described herein. In some cases, the memory 1230 can contain, among other things, a BIOS that can control basic hardware or software operations, such as interactions with peripheral components or devices.

[0208] The processor 1240 can include intelligent hardware devices (e.g., a general-purpose processor, DSP, CPU, microcontroller, ASIC, FPGA, programmable logic device, discrete gate or transistor logic components, discrete hardware components, or any combination thereof). In some cases, the processor 1240 can be configured to operate a memory array using a memory controller. In some cases, the memory controller can be integrated into the processor 1240. The processor 1240 can be configured to execute computer-readable instructions stored in a memory (e.g., memory 1230) to cause the device 1205 to perform various functions (e.g., functions or tasks supporting sidelink candidate resource selection).

[0209] The inter-station communication manager 1245 can manage communication with other base stations 105 and can include a controller or scheduler for collaboratively controlling the communication of the UE 115 with other base stations 105. For example, the inter-station communication manager 1245 can coordinate the scheduling of transmissions to the UE 115 for various interference mitigation techniques such as beamforming or joint transmission. In some examples, the inter-station communication manager 1245 can provide an X2 interface within the LTE / LTE-A wireless communication network technology to provide communication between base stations 105.

[0210] Code 1235 may include instructions for implementing aspects of the present disclosure, including instructions for supporting wireless communication. Code 1235 may be stored in a non-transitory computer-readable medium such as system memory or other types of memory. In some cases, Code 1235 may not be directly executable by the processor 1240, but may (e.g., when compiled and run) cause a computer to perform the functions described herein.

[0211] Figure 13 FIG. shows a flowchart of a method 1300 for supporting sidelink candidate resource selection in accordance with aspects of the present disclosure. Operations of method 1300 may be implemented by a UE 115 or components thereof as described herein. For example, operations of method 1300 may be performed by a communication manager as described with reference to Figures 5 to 8 the description. In some examples, the UE may execute a set of instructions to control functional elements of the UE to perform the functions described herein. Additionally or alternatively, the UE may use dedicated hardware to perform aspects of the functions described herein.

[0212] At 1305, the UE may determine a time window for resource selection for the transmission of a sidelink message from a first UE to a second UE. The operation of 1305 may be performed according to the methods described herein. In some examples, aspects of the operation of 1305 may be performed by a time window component as described with reference to Figures 5 to 8 the description.

[0213] At 1310, the UE may determine a set of candidate resources for the transmission of the sidelink message within the time window, the set of candidate resources corresponding to a threshold percentage of the total resources within the time window that are available for resource selection based on an initial power threshold, a stop power threshold, and power measurements associated with at least one neighboring UE. The operation of 1310 may be performed according to the methods described herein. In some examples, aspects of the operation of 1310 may be performed by a candidate resource selector as described with reference to Figures 5 to 8 the description.

[0214] At 1315, the UE may select a resource from the set of candidate resources for the transmission of the sidelink message. The operation of 1315 may be performed according to the methods described herein. In some examples, aspects of the operation of 1315 may be performed by a candidate resource selector as described with reference to Figures 5 to 8 the description.

[0215] At 1320, the UE may transmit the sidelink message to the second UE via the selected resource. The operation of 1320 may be performed according to the methods described herein. In some examples, aspects of the operation of 1320 may be performed by a sidelink message transmitter as described with reference to Figures 5 to 8 the description.

[0216] Figure 14 FIG. 1400 is a flow chart showing a method for supporting sidelink candidate resource selection in accordance with aspects of the present disclosure. Operations of method 1400 may be implemented by a UE 115 or components thereof as described herein. For example, operations of method 1400 may be performed by a communication manager as described with reference to Figures 5 to 8 the description. In some examples, the UE may execute a set of instructions to control functional elements of the UE to perform the functions described herein. Additionally or alternatively, the UE may use dedicated hardware to perform aspects of the functions described herein.

[0217] At 1405, the UE may determine a time window for resource selection for transmission of a sidelink message from a first UE to a second UE. The operation of 1405 may be performed in accordance with the methods described herein. In some examples, aspects of the operation of 1405 may be performed by a time window component as described with reference to Figures 5 to 8 the description.

[0218] At 1410, the UE may determine a reference signal received power (RSRP) of a reference signal from at least one neighboring UE. The operation of 1410 may be performed in accordance with the methods described herein. In some examples, aspects of the operation of 1410 may be performed by an RSRP component as described with reference to Figures 5 to 8 the description.

[0219] At 1415, the UE may determine a candidate resource set based on the RSRP, an initial power threshold, and a stop power threshold. The operation of 1415 may be performed in accordance with the methods described herein. In some examples, aspects of the operation of 1415 may be performed by a candidate resource selector as described with reference to Figures 5 to 8 the description.

[0220] At 1420, the UE may determine, within the time window, a candidate resource set for transmission of the sidelink message, the candidate resource set corresponding to a threshold percentage of the total resources within the time window that is available for resource selection based on the initial power threshold, the stop power threshold, and power measurements associated with at least one neighboring UE. The operation of 1420 may be performed in accordance with the methods described herein. In some examples, aspects of the operation of 1420 may be performed by a candidate resource selector as described with reference to Figures 5 to 8 the description.

[0221] At 1425, the UE may select a resource for transmission of the sidelink message from the candidate resource set. The operation of 1425 may be performed in accordance with the methods described herein. In some examples, aspects of the operation of 1425 may be performed by a candidate resource selector as described with reference to Figures 5 to 8 the description.

[0222] At 1430, the UE may transmit a sidelink message to a second UE via the selected resources. The operations at 1430 may be performed according to the methods described herein. In some examples, aspects of the operations at 1430 may be performed by a sidelink message transmitter as described with reference to Figures 5 to 8 as described.

[0223] Figure 15 FIG. shows a flow diagram of a method 1500 for supporting sidelink candidate resource selection in accordance with aspects of the present disclosure. The operations of method 1500 may be implemented by a base station 105 or its components as described herein. For example, the operations of method 1500 may be performed by a communication manager as described with reference to Figures 9 to 12 as described. In some examples, the base station may execute a set of instructions to control the functional elements of the base station to perform the functions described herein. Additionally or alternatively, the base station may use dedicated hardware to perform aspects of the functions described herein.

[0224] At 1505, the base station may establish a communication link with a first UE communicating with a second UE via a sidelink communication link. The operations at 1505 may be performed according to the methods described herein. In some examples, aspects of the operations at 1505 may be performed by a communication link manager as described with reference to Figures 9 to 12 as described.

[0225] At 1510, the base station may determine a configuration for sidelink message candidate resource selection from the first UE to the second UE, the configuration being based on an initial power threshold and a stop power threshold. The operations at 1510 may be performed according to the methods described herein. In some examples, aspects of the operations at 1510 may be performed by a candidate resource manager as described with reference to Figures 9 to 12 as described.

[0226] At 1515, the base station may transmit an indication of the configuration to the first UE. The operations at 1515 may be performed according to the methods described herein. In some examples, aspects of the operations at 1515 may be performed by a communication link manager as described with reference to Figures 9 to 12 as described.

[0227] Figure 16 FIG. shows a flow diagram of a method 1600 for supporting sidelink candidate resource selection in accordance with aspects of the present disclosure. The operations of method 1600 may be implemented by a base station 105 or its components as described herein. For example, the operations of method 1600 may be performed by a communication manager as described with reference to Figures 9 to 12 as described. In some examples, the base station may execute a set of instructions to control the functional elements of the base station to perform the functions described herein. Additionally or alternatively, the base station may use dedicated hardware to perform aspects of the functions described herein.

[0228] At 1605, the base station may establish a communication link with a first UE that communicates with a second UE via a sidelink communication link. The operations at 1605 may be performed according to the methods described herein. In some examples, aspects of the operations at 1605 may be performed by a communication link manager as described with reference to Figures 9 to 12 The described communication link manager.

[0229] At 1610, the base station may determine a configuration for candidate resource selection for sidelink messages from the first UE to the second UE, the configuration being based on an initial power threshold and a stop power threshold. The operations at 1610 may be performed according to the methods described herein. In some examples, aspects of the operations at 1610 may be performed by a candidate resource manager as described with reference to Figures 9 to 12 The described candidate resource manager.

[0230] At 1615, the base station may transmit an indication of the configuration to the first UE. The operations at 1615 may be performed according to the methods described herein. In some examples, aspects of the operations at 1615 may be performed by a communication link manager as described with reference to Figures 9 to 12 The described communication link manager.

[0231] At 1620, the base station may transmit an indication of an exclusion range for determining a candidate resource set for sidelink messages, where the exclusion range specifies resources to be excluded from the candidate resource set. The operations at 1620 may be performed according to the methods described herein. In some examples, aspects of the operations at 1620 may be performed by a candidate resource manager as described with reference to Figures 9 to 12 The described candidate resource manager.

[0232] It should be noted that the methods described herein describe possible implementations, and the operations and steps may be rearranged or otherwise modified, and other implementations are possible. Additionally, aspects from two or more of the methods may be combined.

[0233] An overview of aspects of the present disclosure is provided below:

[0234] Aspect 1: A method for wireless communication at a first UE, comprising: determining a time window for resource selection for transmission of a sidelink message from the first UE to a second UE; determining a candidate resource set for transmission of the sidelink message within the time window, the candidate resource set corresponding to at least a threshold percentage of the total resources within the time window that are available for resource selection based on an initial power threshold, a stop power threshold, and power measurements associated with at least one neighboring UE; selecting a resource for transmission of the sidelink message from the candidate resource set; and transmitting the sidelink message to the second UE via the selected resource.

[0235] Aspect 2: The method according to aspect 1 further includes: determining a reference signal received power (RSRP) of a reference signal from at least one neighboring UE; and determining a candidate resource set at least partially based on the RSRP, an initial power threshold, and a stop power threshold.

[0236] Aspect 3: The method according to aspect 2 further includes: determining that the RSRP of the reference signal is higher than the initial power threshold; increasing a power threshold for determining the candidate resource set, the power threshold being between the initial power threshold and the stop power threshold; and determining the candidate resource set at least partially based on the RSRP and the power threshold.

[0237] Aspect 4: The method according to aspect 3 further includes: increasing the power threshold according to an absolute value, a factor of an increment value, a number of retransmissions associated with a sidelink message, a priority of the sidelink message, a packet delay budget (PDB) associated with the sidelink message, a priority of a scheduled transmission of at least one neighboring UE, or any combination thereof.

[0238] Aspect 5: The method according to any one of aspects 3 to 4 further includes: suppressing an increase in the power threshold to exceed the stop power threshold.

[0239] Aspect 6: The method according to any one of aspects 2 to 5 further includes: increasing a size of a time window for resource selection for transmission of a sidelink message; and determining the candidate resource set at least partially based on the increased size of the time window.

[0240] Aspect 7: The method according to aspect 6 further includes: determining that the RSRP is higher than the stop power threshold, wherein the size of the time window is increased at least partially based on the determination that the RSRP is higher than the stop power threshold.

[0241] Aspect 8: The method according to any one of aspects 2 to 7 further includes: moving the time window from a first start time to a second start time after the first start time; and determining the candidate resource set at least partially based on the moved time window.

[0242] Aspect 9: The method according to aspect 8 further includes: determining that the RSRP is higher than the stop power threshold, wherein the time window is moved at least partially based on the determination that the RSRP is higher than the stop power threshold.

[0243] Aspect 10: The method according to any one of aspects 1 to 9 further includes: receiving an indication of an exclusion range for resource selection for transmission of a sidelink message; and determining the candidate resource set at least partially based on the exclusion range, wherein the candidate resource set excludes resources specified by the exclusion range.

[0244] Aspect 11: The method according to aspect 10, wherein the indication is received from a base station via a control channel message.

[0245] Aspect 12: The method according to any one of aspects 1 to 11, further comprising: determining a number of retransmissions associated with a sidelink message; and determining a size of a time window at least in part based on the number of retransmissions.

[0246] Aspect 13: The method according to aspect 12, further comprising: determining that a reference signal received power (RSRP) of a reference signal from at least one neighboring UE is higher than an initial power threshold; reducing the number of retransmissions associated with the sidelink message; increasing the size of the time window at least in part based on the reduced number of retransmissions; and determining a candidate resource set from the time window at least in part based on the increased size.

[0247] Aspect 14: The method according to any one of aspects 1 to 13, further comprising: determining the time window at least in part based on a packet delay budget of the sidelink message.

[0248] Aspect 15: The method according to any one of aspects 1 to 14, further comprising: receiving a configuration for increasing a power threshold for determining a candidate resource set; and determining the candidate resource set at least in part based on the configuration.

[0249] Aspect 16: The method according to aspect 15, wherein the configuration is received from a base station via a control channel message.

[0250] Aspect 17: The method according to any one of aspects 15 to 16, further comprising: determining that a reference signal received power (RSRP) of a reference signal from at least one neighboring UE is higher than an initial power threshold; increasing the power threshold for determining a candidate resource set according to the configuration; and determining the candidate resource set after increasing the power threshold.

[0251] Aspect 18: A method for wireless communication at a base station, comprising: establishing a communication link with a first UE communicating with a second UE via a sidelink communication link; determining a configuration for candidate resource selection for a sidelink message from the first UE to the second UE, the configuration being at least in part based on an initial power threshold and a stop power threshold; and transmitting an indication of the configuration to the first UE.

[0252] Aspect 19: The method according to aspect 18, wherein the configuration indicates an increase in a power threshold for determining a candidate resource set for the sidelink message.

[0253] Aspect 20: The method according to aspect 19, wherein the increase in the power threshold is based on an absolute value, a factor of an incremental value, the number of retransmissions associated with the sidelink message, the priority of the sidelink message, the packet delay budget (PDB) associated with the sidelink message, the priority of the scheduled transmission of at least one neighboring UE, or any combination thereof.

[0254] Aspect 21: The method according to any one of aspects 18 to 20, further comprising: transmitting an indication for determining an exclusion range of a candidate resource set for a sidelink message, wherein the exclusion range specifies resources to be excluded from the candidate resource set.

[0255] Aspect 22: The method according to aspect 21, wherein the indication is transmitted via a control channel message.

[0256] Aspect 23: An apparatus for wireless communication at a first UE, 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 the method according to any one of aspects 1 to 17.

[0257] Aspect 24: An apparatus for wireless communication at a first UE, comprising: at least one component for performing the method according to any one of aspects 1 to 17.

[0258] Aspect 25: A non-transitory computer-readable medium storing code for wireless communication at a first UE, the code comprising instructions executable by a processor to perform the method according to any one of aspects 1 to 17.

[0259] Aspect 26: An apparatus for wireless communication at a base station, 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 the method according to any one of aspects 18 to 22.

[0260] Aspect 27: An apparatus for wireless communication at a base station, comprising: at least one component for performing the method according to any one of aspects 18 to 22.

[0261] Aspect 28: A non-transitory computer-readable medium storing code for wireless communication at a base station, the code comprising instructions executable by a processor to perform the method according to any one of aspects 18 to 22.

[0262] Although aspects of LTE, LTE-A, LTE-A Pro, or NR systems may be described for purposes of example, and the LTE, LTE-A, LTE-A Pro, or NR terminology may be used in many descriptions, the techniques described herein are applicable outside of LTE, LTE-A, LTE-A Pro, or NR systems. For example, the described techniques may be applicable to a variety of other wireless communication systems such as Ultra Mobile Broadband (UMB), Institute of Electrical and Electronics Engineers (IEEE) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, Flash-OFDM, and other systems and radio technologies not explicitly mentioned herein.

[0263] The information and signals described herein may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referred to throughout the description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

[0264] The various illustrative blocks and modules described in connection with the present disclosure may be implemented or performed with a general purpose processor, DSP, ASIC, CPU, FPGA, or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general purpose processor may be a microprocessor, but in the alternative, the processor may be any processor, controller, microcontroller, or state machine. The processor may also be implemented as a combination of computing devices (e.g., a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration).

[0265] The functions described herein may be implemented in hardware, software run by a processor, firmware, or any combination thereof. If implemented in software run by a processor, the functions may be stored on or transmitted via a computer-readable medium as one or more instructions or code. Other examples and implementations are within the scope of the present disclosure and the appended claims. For example, due to the nature of software, the functions described herein may be implemented using software run by a processor, hardware, firmware, hardwiring, or any combination thereof. Features implementing the functions may also be physically located at various positions, including being distributed such that portions of the functions are implemented at different physical locations.

[0266] A computer-readable medium includes both a non-transitory computer storage medium and a communication medium, where the communication medium includes any medium that facilitates transfer of a computer program from one location to another. The non-transitory storage medium can be any available medium that can be accessed by a general purpose or special purpose computer. By way of example and not limitation, the non-transitory computer-readable medium can include random access memory (RAM), read only memory (ROM), electrically erasable programmable ROM (EEPROM), flash memory, compact disc (CD) ROM or other optical disc storage, magnetic disk storage or other magnetic storage devices, or any other non-transitory medium that can be used to carry or store the desired program code in the form of instructions or data structures and that can be accessed by a general purpose or special purpose computer or a general purpose or special purpose processor. Additionally, any connection is properly termed a computer-readable medium. For example, if software is transmitted from a website, server, or other remote source using coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of computer-readable medium. As used herein, disk and disc include CD, laser disc, optical disc, digital versatile disc (DVD), floppy disk, and Blu-ray disc, where disks typically reproduce data magnetically, while discs reproduce data optically using lasers. Combinations of the above are also included within the scope of computer-readable medium.

[0267] As used herein, and as included in the claims, the "or" used in a list of items (e.g., a list that begins with a phrase such as "at least one of... " or "one or more of... ") indicates an inclusive list, such that a list of at least one of A, B, or C, for example, refers to A or B or C or AB or AC or BC or ABC (i.e., A and B and C). Additionally, as used herein, the phrase "based on" should not be construed as a reference to a closed set of conditions. For example, an example step described as "based on condition A" can be based on both condition A and condition B without departing from the scope of the present disclosure. In other words, as used herein, the phrase "based on" should be interpreted in the same manner as the phrase "at least partially based on".

[0268] In the figures, similar components or features may have the same reference numeral. Additionally, various components of the same type can be distinguished by following the reference numeral with a dash and a second label that differentiates between the similar components. If only the first reference numeral is used in the specification, the description applies to any one of the similar components having the same first reference numeral, regardless of the second reference numeral or any subsequent reference numerals.

[0269] The description set forth herein with reference to the drawings describes example configurations and does not represent all examples that may be implemented or that are within the scope of the claims. The term "example" as used herein means "serving as an example, instance, or illustration" and not "preferred" or "superior to other examples." To provide an understanding of the described techniques, the detailed description includes specific details. However, the techniques may be practiced without these specific details. In some instances, well-known structures and devices are shown in block diagram form to avoid obscuring the concepts of the described examples.

[0270] The present description is provided to enable a person of ordinary skill in the art to make or use the present disclosure. Various modifications to the present disclosure will be apparent to a person 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 is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for wireless communication at a first user equipment (UE), comprising: determining a time window for resource selection for transmission of a sidelink message from the first UE to a second UE; determining a reference signal received power (RSRP) of a reference signal from at least one neighboring UE; determining that the RSRP is higher than a stop power threshold; increasing a size of the time window for resource selection for transmission of the sidelink message, wherein the size of the time window is increased at least in part based on the determination that the RSRP is higher than the stop power threshold; determining, within the time window, a candidate resource set for transmission of the sidelink message, the candidate resource set corresponding to a threshold percentage of the total resources within the time window that is available for resource selection based at least in part on an initial power threshold, the stop power threshold, the RSRP, the increased size of the time window, and a power measurement associated with the at least one neighboring UE; selecting a resource for transmission of the sidelink message from the candidate resource set; and transmitting the sidelink message to the second UE via the selected resource.

2. The method according to claim 1, further comprising: determining that the RSRP of the reference signal is higher than the initial power threshold; increasing a power threshold for determining the candidate resource set, the power threshold being between the initial power threshold and the stop power threshold; and determining the candidate resource set at least in part based on the RSRP and the power threshold.

3. The method according to claim 2, further comprising: increasing the power threshold according to: an absolute value, a factor of an incremental value, a number of retransmissions associated with the sidelink message, a priority of the sidelink message, a packet delay budget (PDB) associated with the sidelink message, a priority of a scheduled transmission of the at least one neighboring UE, or any combination thereof.

4. The method according to claim 2, further comprising: inhibiting increasing the power threshold to exceed the stop power threshold.

5. The method according to claim 1, further comprising: moving the time window from a first start time to a second start time after the first start time; and determining the candidate resource set at least in part based on moving the time window.

6. The method according to claim 5, wherein, the time window is moved at least in part based on the determination that the RSRP is higher than the stop power threshold.

7. The method according to claim 1, further comprising: receiving an indication of an exclusion range for resource selection for transmission of the sidelink message; and determining the candidate resource set at least in part based on the exclusion range, wherein the candidate resource set excludes resources specified by the exclusion range.

8. The method according to claim 7, wherein, the indication is received from a base station via a control channel message.

9. The method according to claim 1, further comprising: determining a number of retransmissions associated with the sidelink message; and determining the size of the time window at least in part based on the number of retransmissions.

10. The method according to claim 9, further comprises: determining that the RSRP of the reference signal from the at least one neighboring UE is higher than the initial power threshold; reducing the number of retransmissions associated with the sidelink message; increasing the size of the time window at least in part based on reducing the number of retransmissions; and determining the candidate resource set from the time window at least in part based on the increased size.

11. The method according to claim 1, further comprises: determining the time window at least in part based on the packet delay budget of the sidelink message.

12. The method according to claim 1, further comprises: receiving a configuration for increasing the power threshold for determining the candidate resource set; and determining the candidate resource set at least in part based on the configuration.

13. The method according to claim 12, wherein the configuration is received from a base station via a control channel message.

14. The method according to claim 12, further comprises: determining that the RSRP of the reference signal from the at least one neighboring UE is higher than the initial power threshold; increasing the power threshold for determining the candidate resource set according to the configuration; and determining the candidate resource set after increasing the power threshold.

15. An apparatus for wireless communication at a first user equipment (UE), comprising components configured to perform the method according to any one of claims 1 to 14.

16. A non-transitory computer-readable medium storing instructions that, when executed by a processor of a first user equipment, cause the first user equipment to perform the method according to any one of claims 1 to 14.

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