Measurements for Sidelink Communication

Abstract

Certain aspects of the present disclosure relate to a method for wireless communication by a network entity. The method generally includes: generating a configuration message for a user equipment (UE) to perform one or more reference signal (RS) measurements on one or more resources of a sidelink channel; transmitting the measurement configuration message; receiving a measurement report indicating the results of the one or more RS measurements; and transmitting a scheduling message indicating resources for sidelink transmission on the sidelink channel.

Description

[0001] Cross - Reference to Related Applications

[0002] This application claims priority to U.S. Application No. 17 / 074,037, filed on October 19, 2020, which claims the benefit and priority of U.S. Provisional Application No. 62 / 944,165, filed on December 5, 2019. Both of these applications are assigned to the assignee of this application and are hereby incorporated by reference in their entirety as if fully set forth herein for all applicable purposes.

[0003] Background

[0004] Field of the Disclosure

[0005] Aspects of the present disclosure relate to wireless communication, and more particularly to techniques for sidelink communication.

[0006] Description of Related Art

[0007] Wireless communication systems are widely deployed to provide various telecommunication services such as telephony, video, data, messaging, broadcasting, etc. These wireless communication systems may employ multiple access technologies capable of supporting communication with multiple users by sharing available system resources (e.g., bandwidth, transmit power, etc.). Examples of such multiple access systems include Third Generation Partnership Project (3GPP) Long Term Evolution (LTE) systems, LTE - Advanced (LTE - A) systems, Code Division Multiple Access (CDMA) systems, Time Division Multiple Access (TDMA) systems, Frequency Division Multiple Access (FDMA) systems, Orthogonal Frequency Division Multiple Access (OFDMA) systems, Single - Carrier Frequency Division Multiple Access (SC - FDMA) systems, and Time Division Synchronous Code Division Multiple Access (TD - SCDMA) systems, to name just a few.

[0008] These multiple access technologies have been adopted in various telecommunication standards to provide a common protocol that enables different wireless devices to communicate at the urban, national, regional, and even global levels. New Radio (e.g., 5G NR) is an example of an emerging telecommunication standard. NR is an enhanced set of the LTE mobile standard promulgated by 3GPP. NR is designed to better support mobile broadband Internet access by improving spectral efficiency, reducing costs, improving services, utilizing new spectrums, and better integrating with other open standards using OFDMA with cyclic prefix (CP) on the downlink (DL) and uplink (UL). To this end, NR supports beamforming, multiple - input multiple - output (MIMO) antenna technology, and carrier aggregation.

[0009] However, as the demand for mobile broadband access continues to grow, there is a need for further improvements to NR and LTE technologies. Preferably, these improvements should be applicable to other multiple access technologies and telecommunication standards that employ these technologies.

[0010] Overview

[0011] The systems, methods, and devices of the present disclosure each have several aspects, and no single aspect alone is responsible for their desirable attributes. Without limiting the scope of the present disclosure as set forth in the appended claims, some features will now be briefly discussed. After considering this discussion, and particularly after reading the section entitled "Detailed Description," it will be understood how the features of the present disclosure provide advantages including improved feedback signaling.

[0012] Certain aspects of the present disclosure relate to a method for wireless communication by a network entity. The method generally includes: generating a configuration message for a user equipment (UE) to perform one or more reference signal (RS) measurements on one or more resources of a sidelink channel; transmitting the measurement configuration message; receiving a measurement report indicating the results of the one or more RS measurements; and transmitting a scheduling message indicating resources for sidelink transmission on the sidelink channel.

[0013] Certain aspects of the present disclosure relate to a method for wireless communication by a UE. The method generally includes: performing one or more RS measurements on one or more resources of a sidelink channel; generating a measurement report indicating the results of the one or more RS measurements; and transmitting the measurement report to a network entity to be scheduled for sidelink transmission on the sidelink channel.

[0014] Certain aspects of the present disclosure relate to a method for wireless communication by a UE. The method generally includes: receiving from a network entity a configuration message for transmission of one or more RSs to be used by another UE for RS measurements on one or more resources of a sidelink channel; and taking one or more actions in accordance with the configuration message to facilitate the RS measurements by the other UE.

[0015] Certain aspects of the present disclosure relate to an apparatus for wireless communication by a network entity. The apparatus generally includes a memory and one or more processors coupled to the memory, the one or more processors being configured to: generate a configuration message for a UE to perform one or more RS measurements on one or more resources of a sidelink channel; transmit the measurement configuration message; receive a measurement report indicating the results of the one or more RS measurements; and transmit a scheduling message indicating resources for sidelink transmission on the sidelink channel.

[0016] Certain aspects of the present disclosure relate to an apparatus for wireless communication by a UE. The apparatus generally includes a memory and one or more processors coupled to the memory, the one or more processors configured to: perform one or more RS measurements on one or more resources of a sidelink channel; generate a measurement report indicating the results of the one or more RS measurements; and transmit the measurement report to a network entity scheduled for sidelink transmission on the sidelink channel.

[0017] Certain aspects of the present disclosure relate to an apparatus for wireless communication by a UE. The apparatus generally includes a memory and one or more processors coupled to the memory, the one or more processors configured to: receive a configuration message for transmission of one or more RSs to be used for RS measurements by another UE on one or more resources of a sidelink channel; and take one or more actions based on the configuration message to facilitate the RS measurements by the other UE.

[0018] Certain aspects of the present disclosure relate to an apparatus for wireless communication by a network entity. The apparatus generally includes: means for generating a configuration message for a UE to perform one or more RS measurements on one or more resources of a sidelink channel; means for transmitting the measurement configuration message; means for receiving a measurement report indicating the results of the one or more RS measurements; and means for transmitting a scheduling message indicating resources for sidelink transmission on the sidelink channel.

[0019] Certain aspects of the present disclosure relate to an apparatus for wireless communication by a UE. The apparatus generally includes: means for performing one or more RS measurements on one or more resources of a sidelink channel; means for generating a measurement report indicating the results of the one or more RS measurements; and means for transmitting the measurement report to a network entity scheduled for sidelink transmission on the sidelink channel.

[0020] Certain aspects of the present disclosure relate to an apparatus for wireless communication by a UE. The apparatus generally includes: means for receiving a configuration message for transmission of one or more RSs to be used for RS measurements by another UE on one or more resources of a sidelink channel; and means for taking one or more actions based on the configuration message to facilitate the RS measurements by the other UE.

[0021] Certain aspects of the present disclosure relate to a computer-readable medium having instructions stored thereon that cause a network entity to: generate a configuration message for a UE to perform one or more RS measurements on one or more resources of a sidelink channel; transmit the measurement configuration message; receive a measurement report indicating the results of the one or more RS measurements; and transmit a scheduling message indicating resources for sidelink transmission on the sidelink channel.

[0022] Certain aspects of the present disclosure relate to a computer-readable medium storing instructions that cause a UE to: perform one or more RS measurements on one or more resources of a sidelink channel; generate a measurement report indicating results of the one or more RS measurements; and transmit the measurement report to a network entity scheduled for sidelink transmission on the sidelink channel.

[0023] Certain aspects of the present disclosure relate to a computer-readable medium storing instructions that cause a UE to: receive a configuration message for transmission of one or more RSs to be used for RS measurements to be performed by another UE on one or more resources on a sidelink channel; and take one or more actions based on the configuration message to facilitate the RS measurements to be performed by the other UE.

[0024] To achieve the foregoing and related purposes, one or more aspects include the features that are fully described hereinafter and particularly pointed out in the claims. The following description and the drawings set forth in detail certain illustrative features of one or more aspects. However, these features are merely indicative of the various ways in which the principles of the various aspects may be employed. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] To obtain a more particular description of the features briefly summarized above, aspects may be referred to, some of which are illustrated in the drawings. It is to be noted, however, that the drawings illustrate only certain typical aspects of the present disclosure and are not to be considered limiting of its scope as the description may admit of other equally effective aspects.

[0027] Figure 1 is a block diagram conceptually illustrating an example telecommunications system in accordance with certain aspects of the present disclosure.

[0028] Figure 2 is a block diagram conceptually illustrating the design of an example base station (BS) and user equipment (UE) in accordance with certain aspects of the present disclosure.

[0029] Figure 3A and 3B show a pictorial representation of an example vehicle-to-everything (V2X) system in accordance with some aspects of the present disclosure.

[0030] Figure 4 is a flowchart depicting example operations for wireless communication in accordance with certain aspects of the present disclosure.

[0031] Figure 5 is a flowchart depicting example operations for wireless communication in accordance with certain aspects of the present disclosure.

[0032] Figure 6is a flowchart illustrating example operations for wireless communication in accordance with certain aspects of the present disclosure.

[0033] Figure 7 is a call flow diagram illustrating example operations for scheduling sidelink communication in accordance with certain aspects of the present disclosure.

[0034] Figure 8 is a call flow diagram for scheduling using reference signal configured transmissions in accordance with certain aspects of the present disclosure.

[0035] Figure 9 is a call flow diagram for scheduling using periodically configured RS measurements in accordance with certain aspects of the present disclosure.

[0036] Figure 10 illustrates a communication device that may include various components configured to perform operations for the techniques disclosed herein.

[0037] Figure 11 illustrates a communication device that may include various components configured to perform operations for the techniques disclosed herein.

[0038] For ease of understanding, wherever possible, the same reference numerals have been used to designate identical elements common to the figures. It is contemplated that elements disclosed in one aspect may be beneficially utilized in other aspects without specific recitation.

[0039] Detailed Description

[0040] Aspects of the present disclosure provide apparatus, methods, processing systems, and computer-readable media for sidelink communication.

[0041] The following description provides examples of sidelinks in a communication system, and is not limiting of the scope, applicability, or examples set forth in the claims. Changes may be made to the functionality and arrangement of the elements discussed without departing from the scope of the present disclosure. Various examples may appropriately omit, substitute, or add various procedures or components. For example, the methods described may be performed in an order different from that described, and various steps may be added, omitted, or combined. Also, features described with reference to some examples may be combined in some other examples. For example, any number of aspects set forth herein may be used to implement an apparatus or practice a method. Additionally, the scope of the present disclosure is intended to cover such apparatus or methods practiced using other structures, functionality, or structures and functionality that are supplementary to or in addition to the various aspects of the present disclosure set forth herein. It should be understood that any aspect of the present disclosure disclosed herein may be implemented by one or more elements of a claim. The term "exemplary" is used herein to mean "serving as an example, instance, or illustration." Any aspect described herein as "exemplary" need not be construed as superior or better than other aspects.

[0042] Generally, any number of wireless networks can be deployed in a given geographical area. Each wireless network can support a specific radio access technology (RAT) and can operate on one or more frequencies. The RAT can also be referred to as radio technology, air interface, etc. The frequency can also be referred to as carrier, sub - carrier, frequency channel, tone, sub - band, etc. Each frequency can support a single RAT in a given geographical area to avoid interference between wireless networks of different RATs. In some cases, a 5G NR RAT network can be deployed.

[0043] Figure 1 An example wireless communication network 100 in which aspects of the present disclosure can be implemented is illustrated. For example, the wireless communication network 100 can be an NR system (e.g., a 5G NR network).

[0044] As Figure 1 illustrated, the wireless communication network 100 can include several base stations (BS) 110a - z (each also individually referred to herein as BS 110 or collectively as BS 110) and other network entities. The BS 110 can provide communication coverage for a specific geographical area (sometimes referred to as a "cell"), which can be stationary or can move according to the location of the mobile BS 110. In some examples, the BS 110 can be interconnected with each other and / or interconnected to one or more other BSs or network nodes (not shown) in the wireless communication network 100 using any suitable transport network through various types of backhaul interfaces (e.g., direct physical connection, wireless connection, virtual network, etc.). In Figure 1 the example shown, BS 110a, 110b, and 110c can be macro BSs for macro cells 102a, 102b, and 102c, respectively. BS 110x can be a pico BS for pico cell 102x. BS 110y and 110z can be femto BSs for femto cells 102y and 102z, respectively. A BS can support one or more cells. The BS110 communicates with user equipment (UE) 120a - y (each also individually referred to herein as UE 120 or collectively as UE 120) in the wireless communication network 100. The UE 120 (e.g., 120x, 120y, etc.) can be dispersed throughout the wireless communication network 100, and each UE 120 can be stationary or mobile.

[0045] According to certain aspects, the BS 110 and the UE 120 can be configured for sidelink communication. As Figure 1As shown, UE 120a includes a sidelink manager 122. In accordance with aspects of the present disclosure, the sidelink manager 122 may be configured to perform reference signal (RS) measurements for sidelink communication between UE 120a and UE 120t. BS 110a may also include a sidelink manager 111 that facilitates the RS measurements.

[0046] As Figure 1 shown, UE 120a includes a sidelink manager 122. In accordance with aspects of the present disclosure, the sidelink manager 122 may be configured to determine the distance between UE 120a and UE 120t, and the UE may determine whether to transmit HARQ feedback based on the distance.

[0047] The wireless communication network 100 may also include a relay station (e.g., relay station 110r) (also referred to as a relay, etc.) that receives transmissions of data and / or other information from an upstream station (e.g., BS 110a or UE 120r) and sends transmissions of data and / or other information to a downstream station (e.g., UE 120 or BS 110), or the relay station relays transmissions between the UEs 120 to facilitate communication between the devices.

[0048] The network controller 130 may be coupled to a set of BSs 110 and provide coordination and control of these BSs 110. The network controller 130 may communicate with the BSs 110 via a backhaul. The BSs 110 may also communicate with each other via a wireless or wired backhaul (e.g., directly or indirectly).

[0049] Figure 2 illustrates example components of BS 110a and UE 120a that may be used to implement aspects of the present disclosure (e.g., in Figure 1 the wireless communication network 100).

[0050] At BS 110a, the transmit processor 220 may receive data from the data source 212 and control information from the controller / processor 240. The control information may be used for Physical Broadcast Channel (PBCH), Physical Control Format Indicator Channel (PCFICH), Physical Hybrid ARQ Indicator Channel (PHICH), Physical Downlink Control Channel (PDCCH), Group Common PDCCH (GC PDCCH), etc. The data may be used for Physical Downlink Shared Channel (PDSCH), etc. The processor 220 may process (e.g., encode and symbol map) the data and control information to obtain data symbols and control symbols, respectively. The transmit processor 220 may also generate reference symbols (such as for Primary Synchronization Signal (PSS), Secondary Synchronization Signal (SSS), and Cell-Specific Reference Signal (CRS)). The transmit (TX) Multiple-Input Multiple-Output (MIMO) processor 230 may perform spatial processing (e.g., precoding) on the data symbols, control symbols, and / or reference symbols, if applicable, and may provide the output symbol streams to the modulators (MOD) 232a - 232t. Each modulator 232 may process its respective output symbol stream (e.g., for OFDM, etc.) to obtain an output sample stream. Each modulator may further process (e.g., convert to analog, amplify, filter, and up-convert) the output sample stream to obtain a downlink signal. The downlink signals from the modulators 232a - 232t may be transmitted via the antennas 234a - 234t, respectively.

[0051] At UE 120a, the antennas 252a - 252r may receive the downlink signals from BS 110a and may provide the received signals to the demodulators (DEMOD) in the transceivers 254a - 254r, respectively. Each demodulator 254 may condition (e.g., filter, amplify, down-convert, and digitize) its respective received signal to obtain an input sample. Each demodulator may further process the input sample (e.g., for OFDM, etc.) to obtain received symbols. The MIMO detector 256 may obtain the received symbols from all the demodulators 254a - 254r, perform MIMO detection on these received symbols, if applicable, and provide detected symbols. The receive processor 258 may process (e.g., demodulate, de-interleave, and decode) these detected symbols, provide the decoded data for UE 120a to the data sink 260, and provide the decoded control information to the controller / processor 280.

[0052] On the uplink, at UE 120a, the transmit processor 264 may receive and process data from the data source 262 (e.g., for the physical uplink shared channel (PUSCH)) and control information from the controller / processor 280 (e.g., for the physical uplink control channel (PUCCH)). The transmit processor 264 may also generate reference symbols for reference signals (e.g., sounding reference signals (SRS)). The symbols from the transmit processor 264 may be precoded by the TX MIMO processor 266 when applicable, further processed by a demodulator in the transceiver 254a - 254r (e.g., for SC - FDM, etc.), and transmitted to BS 110a. At BS 110a, the uplink signal from UE 120a may be received by the antenna 234, processed by the modulator 232, detected by the MIMO detector 236 when applicable, and further processed by the receive processor 238 to obtain the decoded data and control information transmitted by UE 120a. The receive processor 238 may provide the decoded data to the data sink 239 and the decoded control information to the controller / processor 240.

[0053] The memories 242 and 282 may store data and program codes for BS 110a and UE 120a, respectively. The scheduler 244 may schedule UEs for data transmission on the downlink and / or uplink.

[0054] The controller / processor 280 and / or other processors and modules at UE 120a may execute or direct the execution of processes for the techniques described herein. As Figure 2 shown, according to aspects described herein, the controller / processor 280 of UE 120a has a sidelink manager 281 that may be configured to perform RS measurements for sidelink channels. In some aspects, BS 110 may also include a sidelink manager 241 that facilitates RS measurements. Although shown at the controller / processor, other components of UE 120a and BS 110a may also be used to perform the operations described herein.

[0055] Figure 3A and 3B shows an illustrative representation of an example vehicle - to - everything (V2X) system according to some aspects of the present disclosure. For example, Figure 3A and 3B the UEs shown may communicate via sidelink channels and may perform sidelink CSI reporting, as described herein.

[0056] In Figure 3A and 3B the V2X systems provided offer two complementary transmission modes. In Figure 3AThe first transmission mode, shown by way of example, involves direct communication between parties in a local area that are in proximity to each other (e.g., also referred to as sidelink communication). In Figure 3B The second transmission mode, shown by way of example, involves network communication through a network, which can be implemented through the Uu interface (e.g., the radio access interface between a radio access network (RAN) and a UE).

[0057] Referring to Figure 3A , the V2X system 300 (e.g., including vehicle-to-vehicle (V2V) communication) is illustrated with two UEs 302, 304 (e.g., vehicles). The first transmission mode allows for direct communication between different parties in a given geographical location. As illustrated, a vehicle can have a wireless communication link 306 (V2P) to an individual (e.g., via a UE) through the PC5 interface. Communication between UEs 302 and 304 can also occur through the PC5 interface 308. Communication from UE 302 to other highway components (e.g., highway component 310, such as a traffic signal or sign) (V2I) can occur through the PC5 interface 312 in a similar manner. For Figure 3A each communication illustrated, two-way communication can occur between the elements, so each element can be both a transmitter and a receiver of information. The V2X system 300 can be a self-managed system implemented without the assistance of a network entity. The self-managed system can achieve improved spectral efficiency, reduced cost, and increased reliability because there is no network service interruption during handover operations for mobile vehicles. The V2X system can be configured to operate in licensed or unlicensed spectrum, whereby any vehicle equipped with the system can access the shared frequency and share information. Such coordinated / shared spectrum operation allows for safe and reliable operation.

[0058] Figure 3B A V2X system 350 for communication between a UE 352 (e.g., a vehicle) and a UE 354 (e.g., a vehicle) through a network entity 356 is shown. These network communications can occur through a discrete node (such as a base station, e.g., an eNB or a gNB), which sends information to and receives information from UEs 352, 354 (e.g., relays information between UEs 352, 354). Network communication through the vehicle-to-network (V2N) links 358 and 310 can be used, for example, for long-range communication between vehicles, such as for communicating that there is a traffic accident at a certain distance ahead along a road or highway. Other types of communication can be sent by the node to the vehicle, such as traffic flow conditions, road hazard warnings, environmental / weather reports, service station availability, and other similar examples. Such data can be obtained from cloud-based shared services.

[0059] In some cases, two or more lower-level entities (e.g., UEs) may communicate with each other using sidelink signals. As described above, V2V and V2X communications are examples of communications that may be transmitted via sidelink. Other applications of sidelink communication may include public safety or service announcement communications, proximity service communications, UE-to-network relay communications, device-to-device (D2D) communications, Internet of Everything (IoE) communications, Internet of Things (IoT) communications, mission-critical mesh communications, and other suitable applications. Generally, a sidelink may refer to a direct link between one lower-level entity (e.g., UE1) and another lower-level entity (e.g., UE2). As such, a sidelink may be used to transmit and receive communications (also referred to herein as "sidelink signals") without relaying the communications through a scheduling entity (e.g., BS), even though the scheduling entity may be used for scheduling or control purposes. In some examples, sidelink signals may be conveyed using licensed spectrum (different from wireless local area networks, which typically use unlicensed spectrum).

[0060] Various sidelink channels may be used for sidelink communication, including Physical Sidelink Discovery Channel (PSDCH), Physical Sidelink Control Channel (PSCCH), Physical Sidelink Shared Channel (PSSCH), and Physical Sidelink Feedback Channel (PSFCH). PSDCH may carry discovery expressions that enable neighboring devices to discover each other. PSCCH may carry control signaling for data transmission (such as sidelink resource configuration or other parameters), while PSSCH may carry data transmission. PSFCH may carry feedback, such as channel state information (CSI) related to sidelink channel quality.

[0061] Example techniques for measurements for sidelink communication

[0062] Certain aspects of the present disclosure generally relate to sidelink communication (e.g., communication between UEs, such as vehicle-to-vehicle <v2v v2x>Communication, such as regarding Figure 3A and 3B as described). In side - link communication, beamforming can be employed to improve performance. For example, a side - link transmitting (Tx) UE can perform precoding on side - link control or data channel transmissions, which results in a directional beam. For side - links in frequency range 1 (FR1) (sub - 6 GHz), beamforming can improve the side - link communication range. For side - links in FR2 (carrier frequencies higher than 6 GHz, or millimeter - wave), beamforming may be required to overcome large - scale fading (e.g., path loss).

[0063] Beamforming also has the potential to increase throughput since multiple beams can use the same time - frequency resources in, for example, an OFDM system. When multiple beams are orthogonal (e.g., have different directions), sharing of time - frequency resources is possible. As an example, multiple side - link Tx UEs can transmit different directional beams on the same resource. As another example, a side - link Tx UE and an uplink Tx UE can transmit different directional beams on the same resource. Certain aspects of the present disclosure relate to resource sharing for side - link communication with the assistance of a base station (BS) (e.g., gNB).

[0064] Figure 4 is a flow chart illustrating an example operation 400 for wireless communication in accordance with certain aspects of the present disclosure. Operation 400 can be performed, for example, by a network entity (such as, for example, BS110a in wireless communication network 100).

[0065] Operation 400 can be implemented as a software component executed and run on one or more processors (e.g., Figure 2 the controller / processor 240). Further, signal transmission and reception by the BS in operation 400 can be implemented, for example, by one or more antennas (e.g., Figure 2 the antenna 234). In certain aspects, transmission and / or reception of signals by the BS can be implemented by obtaining and / or outputting signals via a bus interface of one or more processors (e.g., controller / processor 240).

[0066] Operation 400 may begin, at block 405, with a network entity generating a configuration message for a user equipment (UE) (e.g., Rx UE) to perform one or more reference signal (RS) measurements on one or more resources of a sidelink channel; and at block 410, transmitting the measurement configuration message. At block 415, the network entity may receive a measurement report indicating the results of the one or more RS measurements, and at block 420, transmit a scheduling message indicating resources for sidelink transmissions on the sidelink channel. In some cases, the measurement configuration message is transmitted to another UE (e.g., Tx UE), and the measurement report is received from the other UE. In some cases, the sidelink transmission is between the other UE and the UE.

[0067] In some aspects, performing one or more RS measurements may include performing one or more zero-power (ZP) RS measurements (e.g., also referred to as interference measurements (IM)) on one or more resources of the sidelink channel. In some cases, the sidelink transmission may include a transmission from another UE (e.g., Tx UE) to the UE (e.g., Rx UE). Performing the RS measurements may include performing the RS measurements based on at least one RS transmitted by the other UE.

[0068] In some aspects, the configuration message may indicate to the UE to perform RS measurements for multiple beams, and the measurement report may indicate at least one of the multiple beams. The scheduling message may indicate, based on the measurement report, the beam(s) among the multiple beams to be used for sidelink transmission. In some cases, at least one of the multiple beams may be the beam having the highest signal quality among the multiple beams. In some cases, the measurement report may indicate a parameter indicating the signal quality associated with the multiple beams.

[0069] In some aspects, the resources scheduled for sidelink transmission may be shared by the UE and at least one other UE. The resources may be used for transmissions by at least one other UE for uplink transmissions. In some cases, the resources may be used for transmissions by at least one other UE for sidelink transmissions.

[0070] In some aspects, operation 400 may further include receiving a measurement request, wherein generation of the measurement configuration message is in response to the measurement request. In some aspects, the configuration message may include a measurement configuration message indicating to the UE to perform RS measurements. In some aspects, the configuration message may include an RS configuration message configuring one or more RSs for the RS measurements.

[0071] Figure 5 is a flow diagram depicting an example operation 500 for wireless communication in accordance with certain aspects of the present disclosure. Operation 500 may be performed, for example, by an Rx UE (such as UE 120a in wireless communication network 100, by way of example).

[0072] Operation 500 may be an operation performed by the Rx UE that is complementary to the operation 500 performed by the network entity. Operation 500 may be implemented as a software component executed and run on one or more processors (e.g., Figure 2 the controller / processor 280 of ). Additionally, the signal transmission and reception performed by the UE in operation 500 may be implemented, for example, by one or more antennas (e.g., Figure 2 the antenna 252 of ). In some aspects, the transmission and / or reception of signals by the UE may be implemented by obtaining and / or outputting signals via the bus interface of one or more processors (e.g., the controller / processor 280).

[0073] Operation 500 may begin at block 505 with the UE performing one or more RS measurements on one or more resources of the sidelink channel, and at block 510, generating a measurement report indicating the results of the one or more RS measurements. At block 515, the UE transmits the measurement report to the network entity scheduled for sidelink transmission on the sidelink channel.

[0074] Figure 6 is a flow chart illustrating an example operation 600 for wireless communication in accordance with certain aspects of the present disclosure. Operation 600 may be performed, for example, by a Tx UE (such as, for example, UE 120a in the wireless communication network 100).

[0075] Operation 600 may be an operation performed by the Tx UE that is complementary to the operation 400 performed by the network entity and the operation 500 performed by the Rx UE. Operation 600 may be implemented as a software component executed and run on one or more processors (e.g., Figure 2 the controller / processor 280 of ). Additionally, the signal transmission and reception performed by the UE in operation 600 may be implemented, for example, by one or more antennas (e.g., Figure 2 the antenna 252 of ). In some aspects, the transmission and / or reception of signals by the UE may be implemented by obtaining and / or outputting signals via the bus interface of one or more processors (e.g., the controller / processor 280).

[0076] Operation 600 may begin at block 605 with the UE receiving a configuration message for the transmission of one or more RSs to be used for RS measurements to be performed by another UE on one or more resources on the sidelink channel, and at block 610, taking one or more actions in accordance with the configuration message to facilitate the RS measurements to be performed by the other UE. For example, the Tx UE may transmit the one or more RSs to the other UE in accordance with the configuration message. In the case where the configuration message is for one or more zero-power RS configured resources, the one or more actions may include refraining from using the resources for transmission in accordance with the configuration (e.g., to facilitate ZP RS measurements).

[0077] In some cases, the configuration message may include a measurement configuration message that instructs the other UE to perform RS measurements. In such a case, operation 600 may further include transmitting, to the other UE, a configuration message that instructs the other UE to perform RS measurements. In some cases, the Tx UE may also receive, from the other UE, a measurement report indicating the result of the RS measurement, and transmit the measurement report to a network entity. In other words, the Tx UE may act as a relay for communicating the measurement report from the Rx UE to the network entity (e.g., the BS), as described in more detail herein.

[0078] Figure 7 is a call flow diagram illustrating example operations for scheduling sidelink communication in accordance with certain aspects of the present disclosure. As illustrated, a network entity 701 (e.g., a BS) may optionally receive a scheduling / measurement request 706 from a Tx UE 702. Subsequently, the network entity 701 may instruct a sidelink Rx UE 704 to perform reference signal (RS) measurements on a resource set. For example, the network entity 701 may transmit a measurement configuration 708 to the Rx UE.

[0079] In some cases, the Rx UE may not be directly connected to the network entity 701. In such a case, the measurement configuration 708 may be transmitted to the Tx UE 702, and the sidelink Tx UE 702 may send a measurement indication (e.g., a measurement configuration 710) to the Rx UE 704. At block 712, the Rx UE 704 measures the resource based on the indication. The measurement may be a received signal strength indicator (RSSI), a reference signal received power (RSRP), a reference signal received quality (RSRQ), a channel state information (CSI), or a channel busy rate (CBR) measurement. The Rx UE 704 may then report the measurement to the network entity 701. As described herein, the Rx UE 704 may not be directly connected to the network entity 701, and thus, may report the measurement to the Tx UE 702 (e.g., send a measurement report 714), and the Tx UE 702 may forward the report to the network entity 701 (e.g., send a measurement report 716).

[0080] Subsequently, the network entity 701 makes a scheduling decision based on the measurement report, and at block 718, schedules a sidelink transmission. For example, the network entity may transmit a sidelink (SL) scheduling message 720 to the Tx UE 702 to schedule an SL data transmission 722 to the Rx UE 704.

[0081] In some cases, the Rx UE may be instructed (e.g., via measurement configuration 708) to measure a resource set on which the Tx UE is not transmitting. For example, this resource set may correspond to zero-power (ZP)-CSI-RS resources (also referred to as "CSI interference measurement (IM) resources"). In ZP-CSI-RS resources, the Tx UE does not transmit, but another UE may transmit CSI-RS or other signals in the ZP-CSI-RS resources. Thus, the measurements performed by the RX UE reflect the interference level in this measurement resource set. In other words, the measurement report may indicate the power level of signals from an undesired transmitter (e.g., an undesired transmitter transmitting in the ZP-CSI-RS resources), thereby allowing the network entity to schedule resources shared by multiple UEs. In other words, based on the measurement report, the network entity may be able to determine whether transmissions from the undesired UE(s) will interfere with the reception of transmissions from the Tx UE, and thus make a decision on whether the resources allocated to the undesired UE(s) can be allocated to and reused by the Tx UE.

[0082] In some aspects, the measurement configuration instructs the Rx UE to measure a resource set on which the Tx UE is transmitting. For example, this resource set can be used for a certain reference signal being transmitted by the Tx UE, such as CSI-RS, sounding reference signal (SRS), demodulation reference signal (DMRS), synchronization signal block (SSB), etc. In this case, the measurement at least reflects the signal strength / quality of the Tx UE observed at the Rx UE. In some cases, the Rx UE may be instructed to measure the interference level, the TX UE signal strength / quality, or both. As described herein, the measurement report can be reported by the Rx UE (e.g., to the BS via the Tx UE 702).

[0083] In some aspects, the configured measurement resources may include multiple measurement occasions. For example, the Rx UE may be instructed to measure the RS transmitted during the configured measurement resources. Each of the RS transmissions may have different beamforming applied. For example, each of the RSs may be transmitted in a certain beam direction (e.g., different beam directions). The RS can be CSI-RS, ZP-CSI-RS, SRS, DMRS, or SSB, etc. For example, multiple measurement occasions may be provided for the Tx UE to transmit non-zero power RS (CSI-RS, SSB, etc.). In this case, the purpose of the measurement is for the Rx UE to determine the best beam (or one or more improved beams) among the beam set being transmitted by the Tx UE.

[0084] When reporting measurements, the Rx UE 704 may report measurement results from all measurement occasions, or the Rx UE may report measurement results from some measurement occasions. For example, the Rx UE 704 may select the measurement result with a higher or lower metric, e.g., report the beam with a higher RSRP, or report the beam with a higher RSRQ, or report the beam with a lower RSSI, etc. The Rx UE 704 may also report the index(es) of the reported beam(s), thereby allowing the network entity 701 to identify the beam(s) for SL scheduling.

[0085] As described herein, the BS schedules transmissions from the Tx UE to the Rx UE. The scheduling may be based on measurement reports directly from the Rx UE or relayed by the Tx UE. In some aspects, the BS scheduler may at least indicate the location of the time-frequency resources for the Tx UE to use for SL communication. For example, the scheduler of the BS may determine whether the resources allocated to one or more other sidelink UEs or one or more uplink UEs can be allocated to the Tx UE 702 based on the measurement report. As described herein, the measurement report at least indicates the signal strength / quality from the Tx UE and / or the interference level seen by the Rx UE (e.g., the RSRP measured on the ZP-CSI-RS). Thus, if the interference level is less than a certain threshold and / or if the signal strength / quality from the Tx UE is higher than the threshold, the scheduler may determine that the resources can be allocated to the Tx UE.

[0086] The BS scheduler may also indicate the beam index for the Tx UE to use based on the measurement report. In other words, if the Rx UE is configured to measure and report beam quality based on the number of beams transmitted by the Tx UE, as described herein, the BS may indicate to the Tx UE the beam(s) to use for SL communication based on the measurement report from the Rx UE.

[0087] In some aspects, the indication of measurement by the BS (e.g., the transmission of the measurement configuration 708) may be triggered by a certain event. For example, the measurement may be triggered by a scheduling request (e.g., the scheduling / measurement request 706). The BS may configure the measurement in response to receiving a scheduling request (SR) from the Tx UE or the Rx UE.

[0088] In some cases, the measurement can be triggered by an event at the Tx / Rx UE. For example, when the UE(s) declare a radio link failure (RLF) on the sidelink, the BS can configure the measurement (or the UE can directly perform and report the measurement when the RLF occurs). As another example, when the UE(s) detect a change in the beam pair link (BPL) on the sidelink, the BS can configure the measurement (or the UE can directly perform and report the measurement). As another example, when the UE(s) (e.g., on the sidelink data channel and / or control channel) experience a block error rate (BLER) higher than the BLER target, the BS can configure the measurement (or the UE can directly perform and report the measurement). In some cases, the measurement can be performed by the Rx UE in a periodic manner. For example, the BS can configure periodic measurements for the sidelink by configuring the periodic transmission of the measurement RS.

[0089] Figure 8 is a call flow diagram for SL scheduling using RS configuration for transmission according to certain aspects of the present disclosure. As described herein, the sidelink Tx UE can optionally send a scheduling / measurement request 706 to the network entity 701. For example, when the Tx UE has declared an RLF or experienced a change in BPL, the Tx UE can transmit the scheduling / measurement request 706. Subsequently, the network entity 701 can send an RS configuration 802 to the Tx UE 702, and the Tx UE 702 can transmit the RS configuration 804 to the Rx UE, followed by an RS transmission 808. In some cases, the Rx UE can receive the RS configuration directly from the network entity 701. In other words, if the Rx UE cannot receive the RS configuration directly from the network entity 701, the Tx UE can forward the RS configuration to the Rx UE.

[0090] There may be no explicit indication (configuration) of the measurement from the BS. Instead, when the RS for measurement is configured via the RS configuration, the Rx UE can perform the RS measurement. As illustrated, the Tx UE 702 can transmit the RS (e.g., non-zero power RS) based on the RS configuration 802. In some cases, the RS configuration 802 can indicate ZP RS, in which case the Tx UE does not transmit on the resources indicated for the ZP RS. At block 712, the Rx UE measures the RS (e.g., non-zero power RS and / or zero power RS) and reports the measurement (e.g., directly to the network entity or via the TX UE), allowing the BS to perform sidelink scheduling based on the measurement report.

[0091] Figure 9 is a call flow diagram for SL scheduling using periodically configured RS measurements according to certain aspects of the present disclosure. In other words, there may be no triggering event for the measurement, as illustrated. Additionally, the Rx UE may communicate directly with network entity 701. For example, the RS configuration 902 may be directly transmitted from network entity 701 to Rx UE 704, as illustrated. In some cases, if the Rx UE does not communicate directly with network entity 701, the RS configuration may be transmitted to Tx UE 702, and Tx UE 702 may transmit the RS configuration to Rx UE 704, as described herein. Additionally, the measurement report 904 may be transmitted from the Rx UE to network entity 701, and the SL scheduling message 906 may be transmitted from network entity 701 to Rx UE 704.

[0092] Figure 10 illustrates a communication device 1000 that may include various components (e.g., corresponding to apparatus plus function components) configured to perform operations for the techniques disclosed herein, such as Figure 4 the operations illustrated in. The communication device 1000 includes a processing system 1002 coupled to a transceiver 1008. The transceiver 1008 is configured to transmit and receive signals for the communication device 1000 (such as the various signals described herein) via an antenna 1010. The processing system 1002 may be configured to perform processing functions for the communication device 1000, including processing signals received and / or to be transmitted by the communication device 1000.

[0093] The processing system 1002 includes a processor 1004 coupled to a computer-readable medium / memory 1012 via a bus 1006. In certain aspects, the computer-readable medium / memory 1012 is configured to store instructions (e.g., computer-executable code) that, when executed by the processor 1004, cause the processor 1004 to perform Figure 4 the operations illustrated in or other operations for performing the various techniques discussed herein for distance-based HARQ signaling. In certain aspects, the computer-readable medium / memory 1012 stores code 1014 for generating; code 1016 for receiving / transmitting; code 1018 for determining; and code 1020 for executing. In certain aspects, the processor 1004 has circuitry configured to implement the code stored in the computer-readable medium / memory 1012. The processor 1004 includes circuitry 1022 for generating; circuitry 1024 for receiving / transmitting; circuitry 1026 for determining; and circuitry 1028 for executing.

[0094] Figure 11 illustrates a communication device that may include various components configured to perform the operations disclosed herein, such as, Figure 5 - 6 A communication device 1100 for various components (e.g., corresponding to apparatus-plus-function components) of the operations described in [description not provided]. The communication device 1100 includes a processing system 1102 coupled to a transceiver 1108. The transceiver 1108 is configured to transmit and receive signals for the communication device 1100 (such as the various signals described herein) via an antenna 1110. The processing system 1102 may be configured to perform processing functions for the communication device 1100, including processing signals received and / or to be transmitted by the communication device 1100.

[0095] The processing system 1102 includes a processor 1104 coupled to a computer-readable medium / memory 1112 via a bus 1106. In some aspects, the computer-readable medium / memory 1112 is configured to store instructions (e.g., computer-executable code) that, when executed by the processor 1104, cause the processor 1104 to perform Figure 5 - 6 the operations described in [description not provided] or other operations for performing various techniques for distance-based HARQ signaling discussed herein. In some aspects, the computer-readable medium / memory 1112 stores code 1114 for generation; code 1116 for reception / transmission; code 1118 for RS measurement (e.g., for facilitating one or more actions for RS measurement); and code 1120 for execution. In some aspects, the processor 1104 has circuitry configured to implement the code stored in the computer-readable medium / memory 1112. The processor 1104 includes circuitry 1122 for generation; circuitry 1124 for reception / transmission; circuitry 1126 for RS measurement (e.g., for facilitating one or more actions for RS measurement); and circuitry 1128 for execution.

[0096] Example aspects

[0097] Aspect 1: A method for wireless communication by a network entity, comprising: generating a configuration message for a user equipment (UE) to perform one or more reference signal (RS) measurements on one or more resources of a sidelink channel; transmitting the configuration message; receiving a measurement report indicating results of the one or more RS measurements; and transmitting a scheduling message indicating resources for a sidelink transmission on the sidelink channel.

[0098] Aspect 2: The method of aspect 1, wherein the configuration message is transmitted to another UE, and wherein the measurement report is received from the other UE.

[0099] Aspect 3: The method of any one of aspects 1-2, wherein performing the one or more RS measurements includes performing one or more zero-power RS measurements on one or more resources of the sidelink channel.

[0100] Aspect 4: The method according to any one of Aspects 1 - 3, wherein the sidelink transmission comprises a transmission from another UE to the UE, and wherein performing the one or more RS measurements comprises performing RS measurements based on at least one RS transmitted by the other UE.

[0101] Aspect 5: The method according to any one of Aspects 1 - 4, wherein the configuration message instructs the UE to perform one or more RS measurements for a plurality of beams, and wherein the measurement report further indicates at least one of the plurality of beams.

[0102] Aspect 6: The method according to Aspect 5, wherein the scheduling message indicates, based on the measurement report, the beam among the plurality of beams to be used for sidelink transmission.

[0103] Aspect 7: The method according to Aspect 5, wherein at least one of the plurality of beams comprises the beam having the highest signal quality among the plurality of beams.

[0104] Aspect 8: The method according to any one of Aspects 1 - 7, wherein the resources scheduled for the sidelink transmission are shared by the UE and at least one other UE.

[0105] Aspect 9: The method according to Aspect 8, wherein the resources are used for transmissions made by the at least one other UE for uplink transmission or sidelink transmission.

[0106] Aspect 10: The method according to any one of Aspects 1 - 9, further comprising receiving a measurement request, wherein the generation of the configuration message is in response to the measurement request.

[0107] Aspect 11: A method for wireless communication by a user equipment (UE), comprising: performing one or more reference signal (RS) measurements on one or more resources of a sidelink channel; generating a measurement report indicating the results of the one or more RS measurements; and transmitting the measurement report to a network entity to be scheduled for sidelink transmission on the sidelink channel.

[0108] Aspect 12: The method according to Aspect 11, further comprising: receiving a configuration message instructing the UE to perform one or more RS measurements on one or more resources of the sidelink channel.

[0109] Aspect 13: The method according to any one of Aspects 11 - 12, further comprising: receiving a scheduling message indicating resources for sidelink transmission on the sidelink channel, wherein the sidelink transmission comprises a transmission from another UE to the UE, and wherein performing the one or more RS measurements comprises performing RS measurements based on at least one RS transmitted by the other UE.

[0110] Aspect 14: The method as in any one of Aspects 11 - 13, wherein performing the one or more RS measurements includes performing one or more zero - power RS measurements on one or more resources of the sidelink channel.

[0111] Aspect 15: The method as in any one of Aspects 11 - 14, further comprising receiving a configuration message that indicates to the UE to perform one or more RS measurements on one or more resources of the sidelink channel, wherein the configuration message indicates to the UE to perform one or more RS measurements for multiple beams, and wherein the measurement report further indicates at least one of the multiple beams.

[0112] Aspect 16: The method as in Aspect 15, wherein at least one of the multiple beams includes the beam with the highest signal quality among the multiple beams.

[0113] Aspect 17: The method as in any one of Aspects 11 - 16, further comprising receiving an RS configuration message that configures the transmission of one or more RSs for one or more RS measurements performed by another UE, wherein the one or more RS measurements are in response to the RS configuration message.

[0114] Aspect 18: The method as in any one of Aspects 11 - 17, wherein the one or more RS measurements are performed in response to at least one of the following: radio link failure (RLF) of the sidelink channel; change of beam - to - link on the sidelink channel; or detection of a block error rate higher than a threshold associated with the sidelink transmission.

[0115] Aspect 19: The method as in any one of Aspects 11 - 18, further comprising: generating a measurement request in response to an event; transmitting the measurement request; and receiving a configuration message that indicates to the UE to perform one or more RS measurements on one or more resources of the sidelink channel, the configuration message being in response to the measurement request.

[0116] Aspect 20: A method for wireless communication by a user equipment (UE), comprising: receiving a configuration message associated with the transmission of one or more reference signals (RSs) to be used for RS measurements by another UE on one or more resources on a sidelink channel; and taking one or more actions according to the configuration message to facilitate the RS measurements by the other UE.

[0117] Aspect 21: The method as in Aspect 20, wherein the configuration message includes a measurement configuration message that indicates to the other UE to perform the one or more RS measurements, and the method further comprises: transmitting to the other UE a configuration message that indicates the other UE to perform the one or more RS measurements.

[0118] Aspect 22: The method as in one of Aspects 20 - 21, further comprising: receiving a measurement report from the other UE indicating the result of the RS measurement; and transmitting the measurement report to the network entity.

[0119] Aspect 23: The method as in one of Aspects 20 - 22, further comprising: receiving a scheduling message indicating resources for sidelink transmission on the sidelink channel; and transmitting data to the other UE using the resources.

[0120] Aspect 24: The method as in Aspect 23, wherein the resources scheduled for the sidelink transmission are shared by the UE and at least one other UE.

[0121] Aspect 25: The method as in Aspect 24, wherein the resources are used for transmissions made by the at least one other UE for uplink communication or sidelink transmission.

[0122] Aspect 26: The method as in one of Aspects 20 - 25, wherein the configuration message instructs the UE to transmit the one or more RSs for each of a plurality of beams, and wherein the one or more actions include transmitting the one or more RSs according to the configuration message.

[0123] Aspect 27: The method as in one of Aspects 20 - 26, further comprising: generating a measurement request in response to an event, and transmitting the measurement request to the network entity, the configuration message being in response to the measurement request.

[0124] Aspect 28: The method as in Aspect 27, wherein the event includes at least one of the following: radio link failure (RLF) of the sidelink channel; change of beam pair link on the sidelink channel; or detection of a block error rate higher than a threshold associated with the sidelink channel.

[0125] Aspect 29: The method as in one of Aspects 20 - 28, wherein the one or more RSs include non - zero power RSs.

[0126] Aspect 30: The method as in one of Aspects 20 - 29, wherein the configuration message configures resources for one or more zero - power RSs, and wherein the one or more actions include refraining from using these resources for transmission according to the configuration.

[0127] The electromagnetic spectrum is typically subdivided into various classes, bands, channels, etc. based on frequency / wavelength. In 5G NR, two initial operating bands have been identified as frequency range designations FR1 (410 MHz – 7.125 GHz) and FR2 (24.25 GHz – 52.6 GHz). The frequencies between FR1 and FR2 are generally referred to as mid-band frequencies. Although a part of FR1 is greater than 6 GHz, in various documents and articles, FR1 is typically (interchangeably) referred to as the "sub-6 GHz band". A similar naming issue sometimes occurs with FR2. Although it is different from the extremely high frequency (EHF) band (30 GHz – 300 GHz) identified by the International Telecommunication Union (ITU) as the "millimeter wave" band, FR2 is typically (interchangeably) referred to as the "millimeter wave" band in various documents and articles.

[0128] Taking the above aspects into account, unless otherwise specifically stated, it should be understood that if used in this document, terms such as "sub-6 GHz" can generally represent frequencies that can be less than 6 GHz, can be within FR1, or can include mid-band frequencies. Additionally, unless otherwise specifically stated, it should be understood that if used in this document, terms such as "millimeter wave" can generally represent frequencies that can include mid-band frequencies, can be within FR2, or can be within the EHF band.

[0129] The techniques described herein can be used in a variety of wireless communication technologies, such as NR (e.g., 5G NR), 3GPP Long Term Evolution (LTE), LTE-Advanced (LTE-A), Code Division Multiple Access (CDMA), Time Division Multiple Access (TDMA), Frequency Division Multiple Access (FDMA), Orthogonal Frequency Division Multiple Access (OFDMA), Single Carrier Frequency Division Multiple Access (SC-FDMA), Time Division Synchronous Code Division Multiple Access (TD-SCDMA), and other networks. The terms "network" and "system" are often used interchangeably. CDMA networks can implement radio technologies such as Universal Terrestrial Radio Access (UTRA), cdma2000, etc. UTRA includes Wideband CDMA (WCDMA) and other variants of CDMA. cdma2000 covers the IS-2000, IS-95, and IS-856 standards. TDMA networks can implement radio technologies such as Global System for Mobile Communications (GSM). OFDMA networks can implement radio technologies such as NR (e.g., 5G RA), Evolved UTRA (E-UTRA), Ultra Mobile Broadband (UMB), IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, Flash-OFDMA, etc. UTRA and E-UTRA are part of the Universal Mobile Telecommunications System (UMTS). LTE and LTE-A are UMTS versions that use E-UTRA. UTRA, E-UTRA, UMTS, LTE, LTE-A, and GSM are described in documents from an organization named "3rd Generation Partnership Project" (3GPP). cdma2000 and UMB are described in documents from an organization named "3rd Generation Partnership Project 2" (3GPP2). NR is an emerging wireless communication technology under development.

[0130] The techniques described herein can be used in the wireless networks and radio technologies mentioned above and other wireless networks and radio technologies. For clarity, while aspects herein may be described using terms typically associated with 3G, 4G, and / or 5G wireless technologies, aspects of the present disclosure can be applied in communication systems based on other generations.

[0131] In 3GPP, the term "cell" can refer to the coverage area of a Node B (NB) and / or the NB subsystem serving that coverage area, depending on the context in which the term is used. In an NR system, the terms "cell" and BS, Next Generation Node B (gNB or g B node), Access Point (AP), Distributed Unit (DU), carrier, or Transmission and Reception Point (TRP) may be used interchangeably. A BS may provide communication coverage for macro cells, picocells, femtocells, and / or other types of cells. A macro cell may cover a relatively large geographical area (e.g., with a radius of several kilometers) and may allow unconstrained access by UEs with a service subscription. A picocell may cover a relatively small geographical area and may allow unconstrained access by UEs with a service subscription. A femtocell may cover a relatively small geographical area (e.g., a residence) and may allow constrained access by UEs associated with that femtocell (e.g., UEs in a Closed Subscriber Group (CSG), UEs of users in a residence, etc.). A BS for a macro cell may be referred to as a macro BS. A BS for a picocell may be referred to as a pico BS. A BS for a femtocell may be referred to as a femto BS or a home BS.

[0132] A UE may also be referred to as a mobile station, terminal, access terminal, subscriber unit, station, Customer Premises Equipment (CPE), cellular phone, smart phone, Personal Digital Assistant (PDA), wireless modem, wireless communication device, handheld device, laptop computer, cordless phone, Wireless Local Loop (WLL) station, tablet computer, camera, gaming device, netbook, smartbook, ultrabook, appliance, medical device or equipment, biometric sensor / device, wearable device (such as a smart watch, smart clothing, smart glasses, smart wristband, smart jewelry (e.g., smart ring, smart bracelet, etc.)), entertainment device (e.g., music device, video device, satellite radio, etc.), vehicle component or sensor, smart meter / sensor, industrial manufacturing equipment, Global Positioning System device, or any other suitable device configured to communicate via wireless or wired media. Some UEs may be considered Machine Type Communication (MTC) devices or Evolved MTC (eMTC) devices. MTC and eMTC UEs include, for example, robots, drones, remote devices, sensors, meters, monitors, location tags, etc., which may communicate with a BS, another device (e.g., a remote device), or some other entity. A wireless node may provide connectivity to a network (e.g., a Wide Area Network (such as the Internet) or a cellular network) or provide connectivity to the network, for example, via a wired or wireless communication link. Some UEs may be considered Internet of Things (IoT) devices, which may be Narrowband IoT (NB-IoT) devices.

[0133] Some wireless networks (e.g., LTE) utilize Orthogonal Frequency Division Multiplexing (OFDM) on the downlink and Single Carrier Frequency Division Multiplexing (SC-FDM) on the uplink. OFDM and SC-FDM divide the system bandwidth into multiple (K) orthogonal subcarriers, which are also often referred to as frequency tones, frequency bins, etc. Each subcarrier can be modulated with data. Generally, modulation symbols are transmitted in the frequency domain for OFDM and in the time domain for SC-FDM. The spacing between adjacent subcarriers can be fixed, and the total number of subcarriers (K) can depend on the system bandwidth. For example, the subcarrier spacing can be 15 kHz, and the minimum resource allocation (referred to as a "resource block" (RB)) can be 12 subcarriers (or 180 kHz). Thus, for system bandwidths of 1.25, 2.5, 5, 10, or 20 megahertz (MHz), the nominal Fast Fourier Transform (FFT) size can be equal to 128, 256, 512, 1024, or 2048, respectively. The system bandwidth can also be divided into subbands. For example, a subband can cover 1.8 MHz (e.g., 6 RBs), and for system bandwidths of 1.25, 2.5, 5, 10, or 20 MHz, there can be 1, 2, 4, 8, or 16 subbands, respectively. In LTE, the basic transmission time interval (TTI) or packet duration is a 1 ms subframe.

[0134] NR can utilize OFDM with CP on both the uplink and downlink and includes support for half-duplex operation using TDD. In NR, a subframe is still 1 ms, but the basic TTI is referred to as a slot. A subframe contains a variable number of slots (e.g., 1, 2, 4, 8, 16... slots), which depends on the subcarrier spacing. An NR RB is 12 consecutive frequency subcarriers. NR can support a base subcarrier spacing of 15 kHz, and other subcarrier spacings can be defined relative to the base subcarrier spacing, e.g., 30 kHz, 60 kHz, 120 kHz, 240 kHz, etc. Symbol and slot lengths scale with the subcarrier spacing. The CP length also depends on the subcarrier spacing. Beamforming can be supported and beam directions can be configured dynamically. MIMO transmission with precoding can also be supported. In some examples, the MIMO configuration in the DL can support up to 8 transmit antennas (multi-layer DL transmission with up to 8 streams) and up to 2 streams per UE. In some examples, multi-layer transmission with up to 2 streams per UE can be supported. Aggregation of multiple cells can be supported using up to 8 serving cells.

[0135] In some examples, access to an air interface can be scheduled. A scheduling entity (e.g., a BS) allocates resources for communication among some or all of the devices and equipment within its service area or cell. The scheduling entity may be responsible for scheduling, assigning, reconfiguring, and releasing resources for one or more subordinate entities. That is, for the scheduled communication, the subordinate entities utilize the resources allocated by the scheduling entity. A base station is not the only entity that can be used as a scheduling entity. In some examples, a UE can act as a scheduling entity and can schedule resources for one or more subordinate entities (e.g., one or more other UEs), and the other UEs can utilize the resources scheduled by the UE for wireless communication. In some examples, a UE can act as a scheduling entity in a peer-to-peer (P2P) network and / or in a mesh network. In a mesh network example, UEs can communicate directly with each other in addition to communicating with a scheduling entity.

[0136] In some examples, two or more subordinate entities (e.g., UEs) can communicate with each other using sidelink signals. Real-world applications of such sidelink communication can include public safety, proximity services, UE-to-network relay, vehicle-to-vehicle (V2V) communication, Internet of Everything (IoE) communication, IoT communication, mission-critical mesh, and / or various other suitable applications. Generally, a sidelink signal can refer to a signal that is communicated from one subordinate entity (e.g., UE1) to another subordinate entity (e.g., UE2) without relaying the communication through a scheduling entity (e.g., a UE or a BS), even though a scheduling entity can be used for scheduling and / or control purposes. In some examples, sidelink signals can be communicated using licensed spectrum (different from wireless local area networks, which typically use unlicensed spectrum).

[0137] The various methods disclosed herein include one or more steps or acts for implementing the methods. These method steps and / or acts can be interchanged with one another without departing from the scope of the claims. In other words, unless a specific order of the steps or acts is specified, the order and / or use of the specific steps and / or acts can be altered without departing from the scope of the claims.

[0138] As used herein, the phrase "at least one of" in reference to a list of items refers to any combination of those items, including a single member. As an example, "at least one of a, b, or c" is intended to cover: a, b, c, a - b, a - c, b - c, and a - b - c, as well as any combination having multiple identical elements (e.g., a - a, a - a - a, a - a - b, a - a - c, a - b - b, a - c - c, b - b, b - b - b, b - b - c, c - c, and c - c - c, or any other ordering of a, b, and c).

[0139] As used herein, the term "determine" encompasses a variety of actions. For example, "determine" can include computing, calculating, processing, deriving, researching, looking up (e.g., looking up in a table, database, or other data structure), ascertaining, and the like. Moreover, "determine" can include receiving (e.g., receiving information), accessing (e.g., accessing data in a memory), and the like. Also, "determine" can include parsing, selecting, choosing, establishing, and the like.

[0140] The foregoing description is provided to enable any person skilled in the art to practice the various aspects described herein. Various modifications to these aspects will be readily apparent to those skilled in the art, and the generic principles defined herein can be applied to other aspects. Thus, the claims are not intended to be limited to the aspects shown herein, but are to be accorded the full scope consistent with the language of the claims, where the recitation of a singular element is not intended to mean "one and only one" (unless specifically so stated) but rather "one or more." Unless specifically stated otherwise, the term "some / a" refers to one or more. Elements of the various aspects described throughout this disclosure that are presently known or later come to be known to those of ordinary skill in the art as all structural and functional equivalents thereof are expressly incorporated herein by reference and are intended to be covered by the claims. In addition, nothing disclosed herein is intended to be dedicated to the public, whether or not such disclosure is expressly recited in the claims. No element of a claim should be construed under the provisions of 35 U.S.C. § 112(f), unless the element is expressly recited using the phrase "means for" or, in the case of a method claim, the element is recited using the phrase "step for."

[0141] The various operations of the methods described above can be performed by any suitable means capable of performing the corresponding functions. These means can include various hardware and / or software components and / or modules, including but not limited to circuitry, an application specific integrated circuit (ASIC), or a processor. Generally, where there are operations illustrated in the figures, these operations may have corresponding paired means-plus-function components with similar numbers.

[0142] The various illustrative logical blocks, modules, and circuits described in connection with the present disclosure may be implemented or performed with 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 (PLD), 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 commercially available 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.

[0143] If implemented in hardware, an example hardware configuration may include a processing system in a wireless node. The processing system may be implemented with a bus architecture. Depending on the particular application and overall design constraints of the processing system, the bus may include any number of interconnecting buses and bridges. The bus may link together various circuits including a processor, machine-readable media, and a bus interface. The bus interface may be used to connect a network adapter, etc. to the processing system via the bus. The network adapter may be used to implement the signal processing functions of the PHY layer. In the case of user terminal 120 (see Figure 1 ), a user interface (e.g., keypad, display, mouse, joystick, etc.) may also be connected to the bus. The bus may also link various other circuits such as a timing source, peripherals, voltage regulators, power management circuits, and similar circuits, which are well known in the art and will not be described further herein. The processor may be implemented with one or more general and / or special purpose processors. Examples include microprocessors, microcontrollers, DSP processors, and other circuitry capable of executing software. Depending on the particular application and overall design constraints imposed on the overall system, those of ordinary skill in the art will recognize how best to implement the functionality described with respect to the processing system.

[0144] If implemented in software, each function may be stored on or transmitted via a computer-readable medium as one or more instructions or code. Software should be construed broadly to mean instructions, data, or any combination thereof, whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise. A computer-readable medium includes both a computer storage medium and a communication medium, including any medium that facilitates transfer of a computer program from one place to another. A processor may be responsible for managing the bus and general processing, including executing software modules stored on a machine-readable storage medium. The computer-readable storage medium may be coupled to the processor such that the processor can read from and write to the storage medium. In an alternative, the storage medium may be integrated into the processor. By way of example, a machine-readable medium may include a transmission line, a carrier modulated by data, and / or a computer-readable storage medium with instructions stored thereon separate from a wireless node, all of which may be accessed by the processor via a bus interface. Alternatively or additionally, a machine-readable medium or any part thereof may be integrated into the processor, such as may be the case with a cache and / or a general register file. By way of example, examples of a machine-readable medium may include RAM (Random Access Memory), flash memory, ROM (Read-Only Memory), PROM (Programmable Read-Only Memory), EPROM (Erasable Programmable Read-Only Memory), EEPROM (Electrically Erasable Programmable Read-Only Memory), registers, magnetic disks, optical disks, hard drives, or any other suitable storage medium, or any combination thereof. A machine-readable medium may be embodied in a computer program product.

[0145] Software modules may include a single instruction, or many instructions, and may be distributed across several different code segments, among different programs, and across multiple storage media. A computer-readable medium may include several software modules. These software modules include instructions that, when executed by an apparatus such as a processor, cause a processing system to perform various functions. These software modules may include a transmission module and a reception module. Each software module may reside in a single storage device or be distributed across multiple storage devices. By way of example, when a triggering event occurs, a software module may be loaded from a hard drive into RAM. During execution of a software module, the processor may load some instructions into a cache to improve access speed. One or more cache lines may then be loaded into the general register file for execution by the processor. When referring to the functionality of a software module hereinafter, it will be understood that such functionality is implemented by the processor when the processor executes instructions from the software module.

[0146] Similarly, any connection is properly termed a computer-readable medium. For example, if software is transferred from a web site, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, Digital Subscriber Line (DSL), or wireless technology such as infrared (IR), radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technology such as infrared, radio, and microwave is included in the definition of the medium. As used herein, disk and disc include compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk, and disc, where disk typically magnetically reproduces data, while disc optically reproduces data with a laser. Thus, in some aspects, a computer-readable medium may include a non-transitory computer-readable medium (e.g., a tangible medium). Additionally, for other aspects, a computer-readable medium may include a transitory computer-readable medium (e.g., a signal). Combinations of the above should also be included within the scope of computer-readable media.

[0147] Accordingly, some aspects may include a computer program product for performing the operations given herein. For example, such a computer program product may include a computer-readable medium having instructions stored (and / or encoded) thereon that are executable by one or more processors to perform the operations described herein, such as instructions for performing the operations described herein.

[0148] Furthermore, it should be appreciated that modules and / or other suitable means for performing the methods and techniques described herein may be downloaded and / or otherwise obtained by a user terminal and / or a base station where applicable. For example, such devices can be coupled to a server to facilitate transfer of means for performing the methods described herein. Alternatively, the various methods described herein can be provided via a storage device (e.g., RAM, ROM, a physical storage medium such as a compact disc (CD) or floppy disk, etc.) such that once the storage device is coupled to or provided to the user terminal and / or base station, the device can obtain the various methods. Additionally, any other suitable technology adapted to provide the methods and techniques described herein to a device can be utilized.

[0149] It will be understood that the claims are not limited to the exact configurations and components illustrated above. Various modifications, substitutions, and variations can be made in the layout, operation, and details of the methods and apparatuses described above without departing from the scope of the claims.

Claims

1. A method for wireless communication by a network entity, comprising: receiving a scheduling request from at least one of the first user equipment (UE) or the second UE in response to a change in a beam pair link on a sidelink channel between the first UE and the second UE; generating, after receiving the scheduling request, a configuration message for configuring the first UE to perform one or more reference signal (RS) measurements on one or more resources of the sidelink channel; transmitting the configuration message to the first UE and the second UE; receiving, from the first UE, a measurement report indicating the one or more RS measurements; and transmitting to the second UE a scheduling message scheduling resources for a sidelink transmission on the sidelink channel, wherein the scheduling message is based on the measurement report received from the first UE.

2. The method according to claim 1, wherein the measurement report is also received from the second UE.

3. The method according to claim 1, wherein the one or more RS measurements are based on one or more zero-power RS measurements of the one or more resources of the sidelink channel.

4. The method according to claim 1, wherein the sidelink transmission includes a transmission from the second UE to the first UE, and wherein the one or more RS measurements are based on at least one RS transmitted by the second UE.

5. The method according to claim 1, wherein the configuration message instructs the first UE to perform the one or more RS measurements for a plurality of beams, and wherein the measurement report further indicates at least one of the plurality of beams.

6. The method according to claim 5, wherein the scheduling message indicates, based on the measurement report, the beam to be used for the sidelink transmission among the plurality of beams.

7. The method according to claim 5, wherein the at least one of the plurality of beams includes the beam having the highest signal quality among the plurality of beams.

8. The method according to claim 1, wherein the resources scheduled for the sidelink transmission are shared by the first UE and at least one second UE.

9. The method according to claim 8, wherein the resources are configured for uplink transmission or sidelink transmission by the second UE.

10. A method for wireless communication by a first user equipment (UE), comprising: transmitting a scheduling request to a network entity in response to a change in a beam pair link on a sidelink channel between the first UE and the second UE; receiving, after transmitting the scheduling request, a configuration message for performing one or more reference signal (RS) measurements on one or more resources of the sidelink channel; performing the one or more RS measurements on the one or more resources of the sidelink channel based on the received configuration message; generating a measurement report indicating the one or more RS measurements; transmitting the measurement report to the network entity; and receiving, based on the measurement report, a scheduling message indicating resources for a sidelink transmission on the sidelink channel.

11. The method according to claim 10, further comprising receiving the configuration message, the configuration message indicating to the first UE to perform the one or more RS measurements on the one or more resources of the sidelink channel.

12. The method according to claim 10, further comprising: receiving a scheduling message indicating resources for sidelink transmission on the sidelink channel, where the sidelink transmission includes a transmission from a second UE to the first UE, and where performing the one or more RS measurements includes performing RS measurements based on at least one RS transmitted by the second UE.

13. The method according to claim 10, where performing the one or more RS measurements includes performing one or more zero-power RS measurements on the one or more resources of the sidelink channel.

14. The method according to claim 10, where the configuration message indicates to the first UE to perform the one or more RS measurements for a plurality of beams, and where the measurement report further indicates at least one of the plurality of beams.

15. The method according to claim 14, where the at least one of the plurality of beams includes the beam with the highest signal quality among the plurality of beams.

16. The method according to claim 10, further comprising receiving an RS configuration message that configures the transmission of one or more RSs for the one or more RS measurements performed by a second UE, where the one or more RS measurements are in response to the RS configuration message.

17. The method according to claim 10, further comprising: generating a measurement request in response to an event; transmitting the measurement request; and receiving the configuration message that indicates to the first UE to perform the one or more RS measurements on the one or more resources of the sidelink channel, where the configuration message is received in response to the measurement request.

18. A method for wireless communication by a second user equipment (UE), comprising: transmitting a scheduling request to a network entity in response to a change in the beam-to-link on a sidelink channel between the second UE and a first UE; after transmitting the scheduling request, receiving from the network entity a configuration message that configures the transmission of one or more reference signals (RSs) for RS measurements at the first UE on one or more resources of the sidelink channel; taking one or more actions according to the configuration message to facilitate the RS measurements at the first UE, where the one or more actions include transmitting the one or more RSs according to the configuration message; receiving from the first UE a measurement report indicating the one or more RS measurements; and transmitting the measurement report to the network entity.

19. The method according to claim 18, where the configuration message includes a measurement configuration message that contains an indication for the first UE to perform the one or more RS measurements, and the method further comprises transmitting to the first UE the configuration message indicating the first UE to perform the one or more RS measurements.

20. The method according to claim 18, further comprising: receiving a scheduling message indicating resources for sidelink transmission on the sidelink channel; and using the resources to transmit data to the first UE.

21. The method according to claim 20, wherein the resources scheduled for the sidelink transmission are shared by the second UE and the first UE.

22. The method according to claim 21, wherein the resources are configured for uplink communication or sidelink transmission by the second UE.

23. The method according to claim 18, wherein the configuration message indicates to the second UE to transmit the one or more RSs for each of a plurality of beams.

24. The method according to claim 18, further comprising: generating a measurement request in response to an event and transmitting the measurement request to the network entity, wherein the configuration message is received in response to the measurement request.

25. The method according to claim 24, wherein the event includes at least one of the following: radio link failure (RLF) of the sidelink channel; change of the beam pair link on the sidelink channel; or detection of a block error rate higher than a threshold associated with the sidelink transmission.

26. The method according to claim 18, wherein the one or more RSs include non-zero power RSs.

27. The method according to claim 18, wherein the configuration message configures resources for one or more zero power RSs, and wherein the one or more actions include refraining from using the resources for transmission according to the configuration.

28. An apparatus for wireless communication by a network entity, the apparatus comprising: means for receiving a scheduling request from at least one of the first user equipment (UE) or the second UE in response to a change in a beam pair link on a sidelink channel between the first UE and the second UE; means for generating, after receiving the scheduling request, a configuration message for configuring the first UE to perform one or more reference signal (RS) measurements on one or more resources of the sidelink channel; means for transmitting the configuration message to the first UE and the second UE; means for receiving, from the first UE, a measurement report indicating the one or more RS measurements; and means for transmitting, to the second UE, a scheduling message scheduling resources for sidelink transmission on the sidelink channel, wherein the scheduling message is based on the measurement report received from the first UE.

29. The apparatus according to claim 28, wherein the measurement report is also received from the second UE.

30. The apparatus according to claim 28, wherein the one or more RS measurements are based on one or more zero power RS measurements of the one or more resources of the sidelink channel.

31. The apparatus according to claim 28, wherein the sidelink transmission includes a transmission from the second UE to the first UE, and wherein the one or more RS measurements are based on at least one RS transmitted by the second UE.

32. The device according to claim 28, wherein the configuration message instructs the first UE to perform the one or more RS measurements for a plurality of beams, and wherein the measurement report further indicates at least one of the plurality of beams.

33. The device according to claim 32, wherein the scheduling message instructs, based on the measurement report, the beam to be used for the sidelink transmission among the plurality of beams.

34. The device according to claim 32, wherein at least one of the plurality of beams includes the beam having the highest signal quality among the plurality of beams.

35. The device according to claim 28, wherein the resources scheduled for the sidelink transmission are shared by the first UE and at least one second UE.

36. The device according to claim 35, wherein the resources are configured for uplink transmission or sidelink transmission by the second UE.

37. A device for wireless communication by a first user equipment (UE), the device comprising: means for transmitting a scheduling request to a network entity in response to a change in a beam pair link on a sidelink channel between the first UE and a second UE; means for receiving, after transmitting the scheduling request, a configuration message for performing one or more reference signal (RS) measurements on one or more resources of the sidelink channel; means for performing the one or more RS measurements on the one or more resources of the sidelink channel based on the received configuration message; means for generating a measurement report indicating the one or more RS measurements; means for transmitting the measurement report to the network entity; and means for receiving, based on the measurement report, a scheduling message indicating resources for a sidelink transmission on the sidelink channel.

38. The device according to claim 37, further comprising means for receiving the configuration message that instructs the first UE to perform the one or more RS measurements on the one or more resources of the sidelink channel.

39. The device according to claim 37, further comprising means for receiving a scheduling message indicating resources for a sidelink transmission on the sidelink channel, wherein the sidelink transmission includes a transmission from the second UE to the first UE, and wherein performing the one or more RS measurements includes performing RS measurements based on at least one RS transmitted by the second UE.

40. The device according to claim 37, wherein the means for performing the one or more RS measurements includes means for performing one or more zero-power RS measurements on the one or more resources of the sidelink channel.

41. The device according to claim 37, wherein the configuration message instructs the first UE to perform the one or more RS measurements for a plurality of beams, and wherein the measurement report further indicates at least one of the plurality of beams.

42. The device according to claim 41, wherein at least one of the plurality of beams includes the beam having the highest signal quality among the plurality of beams.

43. The apparatus according to claim 37, further comprising means for receiving an RS configuration message that configures the transmission of one or more reference signals (RSs) for the one or more RS measurements performed by a second UE, wherein the one or more RS measurements are in response to the RS configuration message.

44. The apparatus according to claim 37, further comprising: means for generating a measurement request in response to an event; means for transmitting the measurement request; and means for receiving the configuration message that indicates to the first UE to perform the one or more RS measurements on the one or more resources of the sidelink channel, wherein the configuration message is received in response to the measurement request.

45. An apparatus for wireless communication by a second user equipment (UE), the apparatus comprising: means for transmitting a scheduling request to a network entity in response to a change in a beam pair link on a sidelink channel between the second UE and a first UE; means for receiving, after transmitting the scheduling request, a configuration message that configures the transmission of one or more reference signals (RSs) on one or more resources of the sidelink channel for RS measurements at the first UE; means for taking one or more actions in accordance with the configuration message to facilitate the RS measurements at the first UE, wherein the one or more actions include transmitting the one or more RSs in accordance with the configuration message; means for receiving a measurement report indicating the one or more RS measurements from the first UE; and means for transmitting the measurement report to the network entity.

46. The apparatus according to claim 45, wherein: the configuration message includes a measurement configuration message that includes an indication for the first UE to perform the one or more RS measurements, and the apparatus further comprises means for transmitting the configuration message that indicates to the first UE to perform the one or more RS measurements to the first UE.

47. The apparatus according to claim 45, further comprising: means for receiving a scheduling message that indicates resources for sidelink transmission on the sidelink channel; and means for using the resources to transmit data to the first UE.

48. The apparatus according to claim 47, wherein the resources scheduled for the sidelink transmission are shared by the second UE and the first UE.

49. The apparatus according to claim 47, wherein the resources are configured for uplink communication or sidelink transmission by the second UE.

50. The apparatus according to claim 45, wherein the configuration message indicates to the second UE to transmit the one or more RSs for each of a plurality of beams.

51. The apparatus according to claim 45, further comprising: means for generating a measurement request in response to an event, and means for transmitting the measurement request to a network entity, wherein the configuration message is received in response to the measurement request.

52. The apparatus according to claim 51, wherein the event includes at least one of the following: Radio Link Failure (RLF) of the sidelink channel; The change of the beam pair link on the sidelink channel; or Detecting a block error rate above a threshold associated with sidelink transmission.

53. The apparatus according to claim 45, wherein the one or more RSs include non-zero power RSs.

54. The apparatus according to claim 45, wherein the configuration message is one or more zero power RS configuration resources, and wherein the one or more actions include refraining from using the resources for transmission according to the configuration.

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