Synchronous reference source selection for clock synchronization

Abstract

Various aspects of the present disclosure generally relate to wireless communications. In certain aspects, a wireless communication device may select a synchronization reference source from a plurality of available synchronization reference sources based at least in part on a clock accuracy indicator of the synchronization reference source; and communicate with the synchronization reference source to synchronize a first clock of the wireless communication device with a second clock of the synchronization reference source. Numerous other aspects are provided.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This patent application claims priority to Greek Patent Application No. 20200100133, entitled “SYNCHRONIZATION REFERENCESOURCE SELECTION FOR CLOCK SYNCHRONIZATION”, filed on March 13, 2020, and assigned to the assignee of this application. The disclosure of the prior application is considered part of and incorporated by reference into this patent application. Technical Field

[0003] Aspects of the present disclosure relate generally to wireless communications and are directed to techniques and apparatus for synchronization reference source selection for clock synchronization. Background Art

[0004] Wireless communication systems are widely deployed to provide various radio frequency (RF) telecommunication services, such as telephone, video, data, messaging, and broadcasting. Typical wireless communication systems may employ multiple access technologies that can support communication with multiple users by sharing available system resources (e.g., bandwidth, transmit power, etc.). Examples of such multiple access systems include 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, as well as long term evolution (LTE). LTE / LTE-Advanced is a collection of enhancements to the Universal Mobile Telecommunications System (UMTS) mobile standard promulgated by the Third Generation Partnership Project (3GPP).

[0005] A wireless network may include several base stations (BSs) that can support communications for several user equipments (UEs). The UE may communicate with the BS via a downlink and an uplink. The downlink (or forward link) refers to a communication link from the BS to the UE, and the uplink (or reverse link) refers to a communication link from the UE to the BS. As will be described in more detail herein, a BS may be referred to as a Node B, gNB, access point (AP), radio head, transmit receive point (TRP), new radio (NR) BS, 5G Node B, and the like.

[0006] The above-mentioned multiple access technologies have been used in various telecommunication standards to provide a common protocol that enables different user devices to communicate at a city, country, region, and even global level. NR (also known as 5G) is a collection of enhancements to the LTE mobile standard promulgated by 3GPP. NR is designed to better support mobile broadband Internet access by improving spectrum efficiency, reducing costs, improving services, utilizing new spectrum, and better integrating with orthogonal frequency division multiplexing (OFDM) (CP-OFDM) with cyclic prefix (CP) on the downlink (DL), CP-OFDM and / or SC-FDM (e.g., also known as discrete Fourier transform spread OFDM (DFT-s-OFDM)) on the uplink (UL), and other open standards that support beamforming, multiple input multiple output (MIMO) antenna technology, and carrier aggregation. As the demand for mobile broadband access continues to increase, further improvements to LTE, NR, and other radio access technologies remain useful. Summary of the invention

[0007] In certain aspects, a method of wireless communication performed by a wireless communication device may include: selecting a synchronization reference source from a plurality of available synchronization reference sources based at least in part on a clock accuracy indicator of the synchronization reference source; and communicating with the synchronization reference source to synchronize a first clock of the wireless communication device with a second clock of the synchronization reference source.

[0008] In certain aspects, a wireless communication device for wireless communication may include a memory and one or more processors operably coupled to the memory. The memory and the one or more processors may be configured to: select a synchronization reference source from a plurality of available synchronization reference sources based at least in part on a clock accuracy indicator of the synchronization reference source; and communicate with the synchronization reference source to synchronize a first clock of the wireless communication device with a second clock of the synchronization reference source.

[0009] In certain aspects, a non-transitory computer-readable medium may store one or more instructions for wireless communication. The one or more instructions, when executed by one or more processors of a wireless communication device, may cause the one or more processors to: select a synchronization reference source from a plurality of available synchronization reference sources based at least in part on a clock accuracy indicator of the synchronization reference source; and communicate with the synchronization reference source to synchronize a first clock of the wireless communication device with a second clock of the synchronization reference source.

[0010] In certain aspects, an apparatus for wireless communication may include: a component for selecting a synchronization reference source from a plurality of available synchronization reference sources based at least in part on a clock accuracy indicator of the synchronization reference source; and a component for communicating with the synchronization reference source to synchronize a first clock of a wireless communication device with a second clock of the synchronization reference source.

[0011] As fully described herein with reference to and as illustrated in the accompanying drawings and description, various aspects generally include methods, apparatuses, systems, computer program products, non-transitory computer-readable media, user equipment, base stations, wireless communication devices, and / or processing systems.

[0012] The foregoing has been fairly extensively summarized according to the features and technical advantages of the examples of the present disclosure, so that the following detailed description can be better understood. Additional features and advantages will be described below. The disclosed concepts and specific examples can be easily used as the basis for modifying or designing other structures for achieving the same purpose of the present disclosure. Such equivalent constructions do not depart from the scope of the appended claims. When considered in conjunction with the attached drawings, the characteristics of the concepts disclosed herein, their organization and methods of operation, together with the associated advantages, will be better understood according to the following description. Each of the accompanying drawings is provided for the purpose of illustration and description, rather than as a definition of the limitations of the claims.

[0013] Although various aspects are described in the present disclosure by the description of certain examples, it will be understood by those skilled in the art that such aspects can be implemented in many different arrangements and scenarios. Different platform types, devices, systems, shapes, sizes and / or packaging arrangements can be used to implement the technology described herein. For example, certain aspects can be implemented via integrated chip embodiments and / or other devices based on non-module components (e.g., end-user devices, vehicles, communication devices, computing devices, industrial equipment, retail / purchase equipment, medical devices, or devices that enable artificial intelligence). Aspects can be implemented in chip-level components, modular components, non-modular components, non-chip-level components, device-level components, or system-level components. The device in combination with the described aspects and features may include additional components and features for the implementation and practice of the aspects claimed and described. For example, the transmission and reception of wireless signals may include several components for analog and digital purposes (e.g., hardware components, including antennas, RF chains, power amplifiers, modulators, buffers, (one or more) processors, interleavers, adders, or summers). The aspects described herein are intended to be practiced in various devices, components, systems, distributed arrangements, or end-user devices with different sizes, shapes, and configurations. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order that the above-mentioned features of the present disclosure may be understood in detail, a more specific description briefly summarized above may be made with reference to various aspects, some of which are shown in the attached drawings. However, it should be noted that the attached drawings only show certain typical aspects of the present disclosure and therefore should not be considered to limit the scope of the present disclosure, as the specification may allow other equivalent aspects. The same reference numerals in different drawings may identify the same or similar elements.

[0015] Figure 1 is a diagram illustrating an example of a wireless network according to the present disclosure.

[0016] Figure 2 is a diagram illustrating an example of communication between a base station and a UE in a wireless network according to the present disclosure.

[0017] Figure 3A-3C is a diagram illustrating an example of synchronization reference source selection for clock synchronization according to the present disclosure.

[0018] Figure 4 is a diagram illustrating an example process performed, for example, by a wireless communication device according to the present disclosure. DETAILED DESCRIPTION

[0019] The various aspects of the present disclosure will be described more fully below with reference to the accompanying drawings. However, the present disclosure can be embodied in many different forms and should not be interpreted as being limited to any specific structure or function presented throughout the present disclosure. Instead, these aspects are provided to make the present disclosure detailed and complete, and to fully convey the scope of the present disclosure to those skilled in the art. Based on the teachings herein, it should be understood by those skilled in the art that the scope of the present disclosure is intended to cover any aspect of the disclosure disclosed herein, regardless of whether these aspects are implemented independently of any other aspect of the present disclosure or implemented in combination with any other aspect of the present disclosure. For example, any number of aspects set forth herein can be used to implement a device or practice method. In addition, the scope of the disclosure is intended to cover devices or methods practiced using other structures, functionality, or structures and functionality in addition to the various aspects of the disclosure set forth herein as additional to the various aspects of the disclosure set forth herein. It should be understood that any aspect of the present disclosure can be embodied by one or more elements in the claims.

[0020] Several aspects of telecommunication systems will now be presented with reference to various devices and techniques. These devices and techniques will be described in the following detailed description and illustrated in the accompanying drawings by various blocks, modules, components, circuits, steps, processes, algorithms, etc. (collectively referred to as "elements"). These elements may be implemented using hardware, software, or a combination thereof. Whether such elements are implemented as hardware or software depends on the specific application and the design constraints imposed on the overall system.

[0021] It should be noted that while various aspects may be described using terminology typically associated with 5G or NR radio access technologies (RATs), aspects of the present disclosure may be applied to other RATs, such as 3G RATs, 4G RATs, and / or RATs beyond 5G (e.g., 6G).

[0022] Figure 1is a diagram illustrating an example of a wireless network 100 according to the present disclosure. The wireless network 100 may be or may include elements of a 5G (NR) network and / or an LTE network, among others. The wireless network 100 may include several base stations 110 (shown as BS110a, BS 110b, BS 110c, and BS 110d) and other network entities. A base station (BS) is an entity that communicates with a user equipment (UE), and may also be referred to as an NR BS, Node B, gNB, 5G Node B (NB), access point, transmit receive point (TRP), and the like. Each BS may provide communication coverage for a specific geographic area. In 3GPP, the term "cell" may refer to a coverage area of ​​a BS and / or a BS subsystem serving this coverage area, depending on the context in which the term "cell" is used.

[0023] A BS may provide communication coverage for a macro cell, a pico cell, a femto cell, and / or another type of cell. A macro cell may cover a relatively large geographic area (e.g., a radius of several kilometers) and may allow unrestricted access to UEs with service subscriptions. A pico cell may cover a relatively small geographic area and may allow unrestricted access to UEs with service subscriptions. A femto cell may cover a relatively small geographic area (e.g., a home) and may allow limited access to UEs associated with the femto cell (e.g., UEs in a closed subscriber group (CSG)). A BS for a macro cell may be referred to as a macro BS. A BS for a pico cell may be referred to as a pico BS. A BS for a femto cell may be referred to as a femto BS or a home BS. In Figure 1 In the example shown, BS 110a may be a macro BS for macro cell 102a, BS 110b may be a pico BS for pico cell 102b, and BS 110c may be a femto BS for femto cell 102c. A BS may support one or more (e.g., three) cells. The terms "eNB", "base station", "NR BS", "gNB", "TRP", "AP", "Node B", "5G NB", and "cell" may be used interchangeably herein.

[0024] In some aspects, the cells may not necessarily be stationary, and the geographic area of ​​the cells may move depending on the location of the mobile BS. In some aspects, the BSs may be interconnected with each other and / or with one or more other BSs or network nodes (not shown) in the wireless network 100 through various types of backhaul interfaces such as direct physical connections or virtual networks using any suitable transport network.

[0025] The wireless network 100 may also include a relay station. A relay station is an entity that can receive transmissions of data from an upstream station (e.g., a BS or a UE) and send transmissions of data to a downstream station (e.g., a UE or a BS). A relay station may also be a UE that can relay transmissions for other UEs. Figure 1 In the example shown, a relay BS 110d may communicate with a macro BS 110a and a UE 120d to facilitate communication between the BS 110a and the UE 120d. A relay BS may also be referred to as a relay station, a relay base station, a relay, or the like.

[0026] The wireless network 100 may be a heterogeneous network including different types of BSs, such as a macro BS, a pico BS, a femto BS, a relay BS, etc. These different types of BSs may have different transmit power levels, different coverage areas, and different effects on interference in the wireless network 100. For example, a macro BS may have a high transmit power level (e.g., 5 to 40 watts), while a pico BS, a femto BS, and a relay BS may have a lower transmit power level (e.g., 0.1 to 2 watts).

[0027] The network controller 130 may be coupled to a set of BSs and may provide coordination and control for these BSs. The network controller 130 may communicate with the BSs via a backhaul. The BSs may also communicate with each other directly or indirectly via a wireless or wired backhaul.

[0028] UEs 120 (e.g., 120a, 120b, 120c) may be dispersed throughout the wireless network 100, and each UE may be stationary or mobile. UEs may also be referred to as access terminals, terminals, mobile stations, subscriber units, stations, etc. UEs may be cellular phones (e.g., smart phones), personal digital assistants (PDAs), wireless modems, wireless communication devices, handheld devices, laptop computers, cordless phones, wireless local loop (WLL) stations, tablets, cameras, gaming devices, netbooks, smartbooks, ultrabooks, medical devices or equipment, biometric sensors / devices, wearable devices (smart watches, smart clothing, smart glasses, smart wristbands, smart jewelry (e.g., smart rings, smart bracelets)), entertainment devices (e.g., music or video devices, or satellite radios), vehicle-mounted components or sensors, smart meters / sensors, industrial manufacturing equipment, global positioning system devices, or any other suitable device configured to communicate via wireless or wired media.

[0029] Some UEs may be considered as machine type communication (MTC) UEs, or evolved or enhanced machine type communication (eMTC) UEs. MTC UEs and eMTC UEs include, for example, robots, drones, remote devices, sensors, meters, monitors, and / or location tags that can communicate with a base station, another device (e.g., a remote device), or some other entity. A wireless node may provide connectivity, for example, for or to a network (e.g., a wide area network such as the Internet or a cellular network) via a wired or wireless communication link. Some UEs may be considered as Internet of Things (IoT) devices, and / or may be implemented as NB-IoT (narrowband Internet of Things) devices. Some UEs may be considered as customer premises equipment (Customer Premises Equipment, CPE). UE 120 may be included in a housing that houses components (such as processor components and / or memory components) of UE 120. In some aspects, a processor component and a memory component may be coupled together. For example, a processor component (e.g., one or more processors) and a memory component (e.g., a memory) may be operably coupled, communicatively coupled, electronically coupled, and / or electrically coupled.

[0030] Generally, any number of wireless networks can be deployed in a given geographic area. Each wireless network can support a specific RAT and can operate on one or more frequencies. RAT can also be referred to as radio technology, air interface, etc. Frequency can also be referred to as carrier, frequency channel, etc. Each frequency can support a single RAT in a given geographic area to avoid interference between wireless networks of different RATs. In some cases, NR or 5G RAT networks can be deployed.

[0031] In certain aspects, two or more UEs 120 (e.g., shown as UE 120a and UE 120e) may communicate directly (e.g., without using base station 110 as an intermediary for communicating with each other) using one or more sidelink channels. For example, UE 120 may communicate using peer-to-peer (P2P) communication, device-to-device (D2D) communication, vehicle-to-everything (V2X) protocol (e.g., which may include vehicle-to-vehicle (V2V) protocol or vehicle-to-infrastructure (V2I) protocol), and / or mesh network. In this case, UE 120 may perform scheduling operations, resource selection operations, and / or other operations described elsewhere herein as being performed by base station 110.

[0032] The devices of the wireless network 100 can communicate using an electromagnetic spectrum, which can be subdivided into various categories, frequency bands, channels, etc. based on frequency or wavelength. For example, the devices of the wireless network 100 can communicate using an operating frequency band having a first frequency range (FR1) that can span from 410 MHz to 7.125 GHz, and / or can communicate using an operating frequency band having a second frequency range (FR2) that can span from 24.25 GHz to 52.6 GHz. Frequencies between FR1 and FR2 are sometimes referred to as mid-band frequencies. Although a portion of FR1 is greater than 6 GHz, FR1 is often referred to as a "sub-6 GHz" band. Similarly, FR2 is often referred to as a "millimeter wave" band, although it is different from the extremely high frequency (EHF) band (30 GHz–300 GHz) identified as a "millimeter wave" band by the International Telecommunication Union (ITU). Therefore, unless otherwise specifically stated, it should be understood that the term "below 6 GHz" and the like, if used herein, can broadly refer to frequencies less than 6 GHz, frequencies within FR1, and / or mid-band frequencies (e.g., greater than 7.125 GHz). Similarly, unless otherwise specifically stated, it should be understood that the term "millimeter wave" and the like, if used herein, can broadly refer to frequencies within the EHF band, frequencies within FR2, and / or mid-band frequencies (e.g., less than 24.25 GHz). It is contemplated that the frequencies included in FR1 and FR2 can be modified, and the techniques described herein are applicable to those modified frequency ranges.

[0033] As mentioned above, Figure 1 are provided as examples. Other examples may differ from those regarding Figure 1 Examples described.

[0034] Figure 2 is a diagram illustrating an example 200 of base station 110 communicating with UE 120 in wireless network 100 according to the present disclosure. Base station 110 may be equipped with T antennas 234a through 234t, and UE 120 may be equipped with R antennas 254a through 254r, where in general T≥1 and R≥1.

[0035] At the base station 110, the transmit processor 220 may receive data for one or more UEs from the data source 212, select one or more modulation and coding schemes (MCS) for each UE based at least in part on a channel quality indicator (CQI) received from the UE, process (e.g., encode and modulate) the data for each UE based at least in part on the (one or more) MCS selected for each UE, and provide data symbols for all UEs. The transmit processor 220 may also process system information (e.g., for semi-static resource partitioning information (SRPI)) and control information (e.g., CQI requests, grants, and / or upper layer signaling) and provide overhead symbols and control symbols. The transmit processor 220 may also generate reference symbols for reference signals (e.g., cell-specific reference signals (CRS) or demodulation reference signals (DMRS)) and synchronization signals (e.g., primary synchronization signals (PSS) or secondary synchronization signals (SSS)). A transmit (TX) multiple-input multiple-output (MIMO) processor 230 may perform spatial processing (e.g., precoding) on ​​data symbols, control symbols, overhead symbols, and / or reference symbols, if applicable, and may provide T output symbol streams to T modulators (MOD) 232a to 232t. Each modulator 232 may process a corresponding output symbol stream (e.g., for OFDM, etc.) to obtain an output sample stream. Each modulator 232 may further process the output sample stream (e.g., convert to analog, amplify, filter, and upconvert) to obtain a downlink signal. The T downlink signals from modulators 232a to 232t may be transmitted via T antennas 234a to 234t, respectively.

[0036] At UE 120, antennas 252a to 252r may receive downlink signals from base station 110 and / or other base stations, and may provide received signals to demodulators (DEMOD) 254a to 254r, respectively. Each demodulator 254 may condition (e.g., filter, amplify, downconvert, and digitize) the received signal to obtain input samples. Each demodulator 254 may further process the input samples (e.g., for OFDM, etc.) to obtain received symbols. A MIMO detector 256 may obtain received symbols from all R demodulators 254a to 254r, perform MIMO detection on the received symbols (if applicable), and provide detected symbols. A receive processor 258 may process (e.g., demodulate and decode) the detected symbols, provide decoded data for UE 120 to a data sink 260, and provide decoded control information and system information to a controller / processor 280. The term "controller / processor" may refer to one or more controllers, one or more processors, or a combination thereof. The channel processor may determine a reference signal received power (RSRP) parameter, a received signal strength indicator (RSSI) parameter, a reference signal received quality (RSRQ) parameter, and / or a CQI parameter, etc. In some aspects, one or more components of the UE 120 may be included in the housing 284.

[0037] The network controller 130 may include a communication unit 294, a controller / processor 290, and a memory 292. The network controller 130 may include, for example, one or more devices in a core network. The network controller 130 may communicate with the base station 110 via the communication unit 294.

[0038] Antennas (e.g., antennas 234a to 234t and / or antennas 252a to 252r) may include or may be included in one or more antenna panels, antenna groups, sets of antenna elements, and / or antenna arrays, etc. Antenna panels, antenna groups, sets of antenna elements, and / or antenna arrays may include one or more antenna elements. Antenna panels, antenna groups, sets of antenna elements, and / or antenna arrays may include sets of coplanar antenna elements and / or sets of non-coplanar antenna elements. Antenna panels, antenna groups, sets of antenna elements, and / or antenna arrays may include antenna elements within a single housing and / or antenna elements within multiple housings. Antenna panels, antenna groups, sets of antenna elements, and / or antenna arrays may include antenna elements coupled to one or more transmit and / or receive components (such as Figure 2 One or more antenna elements of one or more components).

[0039] On the uplink, at the UE 120, a transmit processor 264 may receive and process data from a data source 262 and control information from a controller / processor 280 (e.g., for reports including RSRP, RSSI, RSRQ, and / or CQI). The transmit processor 264 may also generate reference symbols for one or more reference signals. The symbols from the transmit processor 264 may be precoded by a TX MIMO processor 266 (if applicable), further processed by demodulators 254a through 254r (e.g., for DFT-s-OFDM or CP-OFDM), and transmitted to the base station 110. In some aspects, the modulator and demodulator (e.g., MOD / DEMOD 254) of the UE 120 may be included in a modem of the UE 120. In some aspects, the UE 120 includes a transceiver. The transceiver may include any combination of antenna(s) 252, modulator and / or demodulator 254, MIMO detector 256, receive processor 258, transmit processor 264, and / or TX MIMO processor 266. The transceiver may be used by a processor (e.g., controller / processor 280) and memory 282 to perform operations described herein (e.g., as described in reference to Figure 3A-3C and Figure 4 Aspects of any of the methods described).

[0040] At the base station 110, uplink signals from the UE 120 and other UEs may be received by the antenna 234, processed by the demodulator 232, detected by the MIMO detector 236 (if applicable), and further processed by the receive processor 238 to obtain decoded data and control information sent by the UE 120. The receive processor 238 may provide the decoded data to the data sink 239 and provide the decoded control information to the controller / processor 240. The base station 110 may include a communication unit 244 and communicate with the network controller 130 via the communication unit 244. The base station 110 may include a scheduler 246 to schedule the UE 120 for downlink and / or uplink communications. In some aspects, the modulator and demodulator (e.g., MOD / DEMOD 232) of the base station 110 may be included in a modem of the base station 110. In some aspects, the base station 110 includes a transceiver. The transceiver may include any combination of antenna(s) 234, modulator and / or demodulator 232, MIMO detector 236, receive processor 238, transmit processor 220, and / or TX MIMO processor 230. The transceiver may be used by a processor (e.g., controller / processor 240) and memory 242 to perform operations described herein (e.g., as described in reference to Figure 3A-3C and Figure 4 Aspects of any of the methods described).

[0041] As described in greater detail elsewhere herein, the controller / processor 240 of the base station 110, the controller / processor 280 of the UE 120, and / or Figure 2 Any other component(s) of the base station 110 may perform one or more techniques associated with selecting a synchronization reference source for clock synchronization. For example, the controller / processor 240 of the base station 110, the controller / processor 280 of the UE 120, and / or Figure 2 Any other component(s) may perform or direct e.g. Figure 4 400 and / or other processes as described herein. Memories 242 and 282 may store data and program codes for base station 110 and UE 120, respectively. In some aspects, memory 242 and / or memory 282 may include a non-transitory computer-readable medium storing one or more instructions (e.g., code and / or program code) for wireless communication. For example, one or more instructions, when executed (e.g., directly, or after compilation, conversion, and / or interpretation) by one or more processors of base station 110 and / or UE 120, may cause one or more processors, UE 120, and / or base station 110 to perform or direct, for example, Figure 4 The operations of process 400 and / or other processes described herein. In some aspects, executing instructions may include running instructions, converting instructions, compiling instructions, and / or interpreting instructions, etc.

[0042] In some aspects, a wireless communication device (such as BS 110, UE 120, etc.) may include: a component for selecting a synchronization reference source from a plurality of available synchronization reference sources based at least in part on a clock accuracy indicator of the synchronization reference source; and a component for communicating with the synchronization reference source to synchronize a first clock of the wireless communication device with a second clock of the synchronization reference source, etc. In some aspects, such components may include a combination of Figure 2 One or more components of the UE 120 described herein, such as the controller / processor 280, the transmit processor 264, the TX MIMO processor 266, the MOD 254, the antenna 252, the DEMOD 254, the MIMO detector 256, the receive processor 258, etc. In some aspects, such components may include a combination of Figure 2 One or more components of BS 110 are depicted, such as antenna 234, DEMOD 232, MIMO detector 236, receive processor 238, controller / processor 240, transmit processor 220, TX MIMO processor 230, MOD 232, antenna 234, and the like.

[0043] Although Figure 2The blocks in the 200 and 210 are shown as distinct components, but the functionality described above with respect to these blocks may be implemented in a single hardware, software, or combined component or in various combinations of components. For example, the functionality described with respect to the transmit processor 264, the receive processor 258, and / or the TX MIMO processor 266 may be performed or under the control of the controller / processor 280.

[0044] As mentioned above, Figure 2 are provided as examples. Other examples may differ from those regarding Figure 2 Examples described.

[0045] In some communication systems, clock synchronization can be used to synchronize communications, synchronize device control, and so on. Some wireless communication devices may include a global positioning system (GPS) clock to achieve clock synchronization. However, other wireless communication devices may lack a GPS clock, or may require a higher level of clock synchronization than can be achieved using a GPS clock. For example, in machine type communications, precision manufacturing, controlled dismantling, and other types of use cases, precise clock synchronization may be required. In a wired network, wired devices may use the Network Time Protocol (NTP) to achieve clock synchronization. For example, a wired device may send and / or receive information identifying a clock offset and / or propagation time, based on which a round trip time (RTT) value is determined to synchronize the clock.

[0046] However, in wireless communications, instead of a single path connecting a collection of wired devices, a collection of wireless communication devices may be connected via multiple paths. For example, a wireless communication device may communicate via a line-of-sight (LOS) path, a collection of non-line-of-sight (NLOS) paths, and the like. When multiple paths are possible, in order to determine the propagation time for clock synchronization, the wireless communication device may match the power delay profile (PDP) of a link to another wireless communication device and a link from another wireless communication device, ensuring that the PDP measurement is performed using a link with a threshold link capacity or quality (e.g., a threshold signal strength, bandwidth, reference signal received power, signal to interference noise ratio, signal to noise ratio, link capacity, etc.), and the like. For a link with a particular wireless communication device, different synchronization reference sources (e.g., a wireless communication device with which a particular wireless communication device may attempt to synchronize a clock) may have different link capacities. This may result in different levels of synchronization accuracy when a particular wireless communication device attempts to communicate with another wireless communication device using a particular link to synchronize a clock.

[0047] Furthermore, each synchronization reference source may attempt to maintain clock synchronization with an ultimate synchronization reference source (e.g., a device that provides network timing from which all other synchronization reference sources attempt to derive synchronization timing). However, synchronization errors may be compounded across communication hops from the ultimate synchronization reference source. For example, a first BS may synchronize a first clock with, for example, a timing server at a first error level, a relay BS may synchronize a second clock with the first clock at a second error level (e.g., the sum of the first error level and an additional error level), a UE may synchronize a third clock with the second clock at a third error level (e.g., the sum of the second error level and the additional error level), and so on. This may cause certain synchronization reference sources to be more closely synchronized with the network time than other synchronization reference sources, and / or to be able to achieve a higher level of synchronization for a particular wireless communication device than other synchronization reference sources.

[0048] Certain aspects described herein enable selection of a synchronization reference source for clock synchronization. For example, a wireless communication device may determine the accuracy level of multiple synchronization reference sources and / or the link capacity of a link with multiple synchronization reference sources. Based at least in part on the accuracy level and / or the link capacity or quality, the wireless communication device may select a specific synchronization reference source to communicate with to perform a clock synchronization process. Additionally or alternatively, the wireless communication device may select a specific reference source based at least in part on one or more other accuracy factors (such as communication mode type, PDP parameters, etc.). In this way, the wireless communication device ensures that the clock of the wireless communication device is synchronized with a higher level of accuracy relative to selecting a synchronization reference source using other techniques.

[0049] Figure 3A-3C is a diagram illustrating an example 300 of synchronization reference source selection for clock synchronization according to the present disclosure.

[0050] like Figure 3A As shown, example 300 may include a wireless communication device (e.g., UE 120 or BS 110) communicating with one or more other devices in the network. For example, the wireless communication device 305 may communicate with the UE 120 via a sidelink connection. Additionally or alternatively, the wireless communication device 305 may communicate with one or more BS 110. For example, the wireless communication device 305 may communicate with BS 110-1 via a LOS path, a NLOS path (e.g., via reflection from an object, a building, a geographic feature, etc.), etc. Similarly, the wireless communication device 305 may communicate with another BS 110-2 (e.g., via a LOS path). In some aspects, other types of devices may serve as synchronization reference sources, such as an integrated access and backhaul (IAB) node, a timing server, a central server, a serving BS, a location management function (LMF), etc.

[0051] like Figure 3B As shown, and by reference numeral 310, the wireless communication device 305 may receive a set of clock accuracy indicators from a set of synchronization reference sources. For example, the wireless communication device 305 may receive a first clock accuracy indicator from BS 110-1, a second clock accuracy indicator from UE 120, a third clock accuracy indicator from BS 110-2, and so on. In this case, the wireless communication device 305 may receive the clock accuracy indicator via a synchronization accuracy message sent in a master information block (MIB), a system information block (SIB), a radio resource control (RRC) message, a medium access control (MAC) control element (CE), a downlink control information (DCI) message), a sidelink (SL) control information (SCI), a SL MAC CE, a SL-RRC, and the like. Additionally or alternatively, the wireless communication device 305 may receive a positioning protocol type message (e.g., a higher layer NR positioning protocol A message that is transparent to the physical layer) to identify information associated with the synchronization clock.

[0052] In certain aspects, the wireless communication device 305 may initiate a clock synchronization process. For example, the wireless communication device 305 may send broadcast signaling, multicast signaling, unicast signaling, etc. to request clock synchronization with a set of synchronization reference sources. Additionally or alternatively, one or more synchronization reference sources may periodically send information associated with enabling clock synchronization. For example, the BS 110-1 may periodically broadcast, multicast, or unicast information identifying clock accuracy, link capacity or quality, etc. to the wireless communication device 305 to enable the wireless communication device 305 to select a synchronization reference source.

[0053] In certain aspects, wireless communication device 305 may receive a clock accuracy indicator that identifies a particular level of accuracy for synchronization. For example, a synchronization reference source may identify a level of accuracy for its own clock that is no higher than a level of accuracy for another clock to which the synchronization reference source synchronizes its own clock. In other words, if UE 120 communicates with BS 110-1 to synchronize a first clock of UE 120 with a second clock of BS 110-1, UE 120 may send a clock accuracy indicator that indicates a level of accuracy for the first clock that is less than or equal to a level of accuracy for the second clock.

[0054] In this case, the timing reference from which each other device in the network derives network timing can be associated with the highest level of accuracy, and each other device can be associated with a lower level of accuracy based at least in part on deriving network timing from the timing reference or deriving network timing from another device that derives network timing from the timing reference. In some aspects, each hop from the timing reference can correspond to a level of accuracy. For example, when BS 110-1 is a timing reference (e.g., having a clock source such as an atomic clock), BS 110-1 can be classified as having level 1 accuracy. In this case, UE 120 can communicate with BS 110-1 to synchronize time and can be classified as having level 2 accuracy. By way of further example, if wireless communication device 305 communicates with UE 120 to synchronize timing, wireless communication device 305 can be classified as having level 3 accuracy. Other accuracy levels or synchronization scenarios may be possible.

[0055] In certain aspects, the accuracy level may be based at least in part on the coverage status. For example, the wireless communication device 305 may determine that the UE 120 is outside the coverage area of ​​the cell that includes the wireless communication device 305, and may determine that the accuracy level of the UE 120 is a lower level than the synchronization reference source within the coverage area of ​​the cell. Additionally or alternatively, the wireless communication device 305 may determine the accuracy level based at least in part on the link type (such as sidelink, access link, etc.).

[0056] In some aspects, the wireless communication device 305 may determine the link capacity or quality of the link with the synchronization reference source. For example, the wireless communication device 305 may determine the bandwidth, link capacity or quality, signal strength, etc. of the sidelink with UE 120, the LOS path with BS 110-1, the NLOS path with BS110-1, etc. In addition or alternatively, the wireless communication device 305 may determine the PDP parameters. For example, the wireless communication device 305 may determine (e.g., at least in part based on the timestamp) the maximum delay path number, the amplitude of the path, the range of the amplitude of the path, the minimum amplitude of the path, the delay of the path, etc. In some aspects, the wireless communication device 305 may determine the type of communication for the synchronization reference source. For example, based at least in part on the received clock accuracy indicator, the wireless communication device 305 may determine whether the communication type is BS-UE communication, server-to-client communication, broadcast communication, multicast communication, UE-to-UE communication, peer-to-peer communication, etc.

[0057] like Figure 3BAs further shown, and indicated by reference numeral 315, the wireless communication device 305 may select a synchronization reference source. For example, based at least in part on the accuracy indicator, link capacity or quality, etc., the wireless communication device 305 may select the BS 110-2 as a synchronization reference source with which to synchronize the clock of the wireless communication device 305. Additionally or alternatively, the wireless communication device 305 may select the synchronization reference source based at least in part on one or more other factors, such as PDP parameters, communication type, type of clock synchronization process that may be used, etc.

[0058] In some aspects, the wireless communication device 305 can rank the hierarchy of synchronization reference sources and select a synchronization reference source based at least in part on the hierarchy of the synchronization reference source. For example, the wireless communication device 305 can identify one or more synchronization reference sources that provide the cell that the wireless communication device 305 is accessing, and can select the synchronization reference source with the highest level of accuracy among the one or more synchronization reference sources that provide the cell. In this case, when the wireless communication device 305 does not identify the synchronization reference source that provides the cell, the wireless communication device 305 can identify one or more coverage area inner link synchronization reference sources and select a specific coverage area inner link synchronization reference source with the highest level of accuracy. In addition, when the wireless communication device 305 does not identify the coverage area inner link synchronization reference source, the wireless communication device 305 can identify the coverage area outer link synchronization reference source having a clock synchronized with the synchronization reference source within the coverage area from one or more coverage area outer link synchronization reference sources. In addition, when the wireless communication device 305 does not identify any downlink synchronization reference source outside the coverage area that has a clock synchronized with the synchronization reference source within the coverage area, the wireless communication device 305 can identify and select from any downlink synchronization reference source outside the coverage area that does not have a clock synchronized with the synchronization reference source within the coverage area (for example, a clock synchronized with other downlink synchronization reference sources outside the coverage area).

[0059] like Figure 3CAs shown, and by reference numerals 320 and 325, the wireless communication device 305 may perform a clock synchronization process. For example, the wireless communication device 305 may communicate with the BS 110-2 using wireless RF signals to synchronize the first clock of the wireless communication device 305 with the second clock of the BS 110-2. The wireless communication device 305 may perform a synchronization process according to a synchronization mode. The synchronization mode may include RTT-based synchronization, one-way synchronization, and / or PDP-based synchronization, etc. In this case, the wireless communication device 305 may send a message including a timestamp of the message, a mode type (e.g., RTT synchronization, one-way synchronization, etc.), etc. For example, the wireless communication device 305 may obtain one or more RTT measurements associated with one or more RF signals, one or more PDP measurements associated with one or more RF signals, and / or one or more one-way synchronization measurements associated with one or more RF signals, etc. By way of further example, for PDP-based synchronization, the BS 110-2 may perform one or more PDP measurements and send a feedback message reporting the PDP measurements (e.g., as a list of reference signal received power (RSRP) measurements with different reference signals), one or more timestamps, etc. The reference signal may include one or more positioning reference signals (eg, a downlink positioning reference signal and / or a sounding reference signal used for positioning).

[0060] The time offset between BS 110-2 and wireless communication device 305 can be determined by cross-validation between the PDP measurement of BS 110-2 and the PDP measurement received from wireless communication device 305. The earliest common peak in the two PDP measurements can be considered as the time offset, while spurious early paths detected by only one node due to noise can be rejected (e.g., as a form of outlier rejection). The earliest common peak can be a LOS path in the channel or a NLOS path in the channel. Consideration of NLOS paths may be different from positioning operations, in which LOS propagation time may be most valuable for position estimation.

[0061] Additionally or alternatively, for one-way synchronization, BS 110-2 may forgo sending a response and may synchronize the second clock to align with the first clock. In some aspects, the wireless communication device 305 may set a clock accuracy level for its own clock. For example, the wireless communication device 305 may set the clock accuracy level for its own clock to be less than or equal to the clock accuracy level of the clock of BS 110-2. In this way, the wireless communication device 305 may advertise a clock accuracy level to enable other devices to synchronize with the clock of the wireless communication device 305.

[0062] As mentioned above, Figure 3A-3C are provided as examples. Other examples may differ from those regarding Figure 3A-3C Examples described.

[0063] Figure 4 is a flow chart of an example process 400 for reference source selection for clock synchronization. In some aspects, Figure 4 One or more process blocks of may be performed by a wireless communication device (eg, BS 110, UE 120, wireless communication device 305, etc.).

[0064] like Figure 4 As shown, process 400 may include selecting a synchronization reference source from a plurality of available synchronization reference sources based at least in part on a clock accuracy indicator of the synchronization reference source (block 410). For example, as described above, a wireless communication device (e.g., using controller / processor 240, controller / processor 280, etc.) may select a synchronization reference source from a plurality of available synchronization reference sources based at least in part on a clock accuracy indicator of the synchronization reference source (block 410).

[0065] like Figure 4 As further shown, process 400 may include communicating with a synchronization reference source to synchronize a first clock of the wireless communication device with a second clock of the synchronization reference source (block 420). For example, as described above, the wireless communication device (e.g., using antenna 234, DEMOD 232, MIMO detector 236, receive processor 238, controller / processor 240, transmit processor 220, TX MIMO processor 230, MOD 232, antenna 252, DEMOD 254, MIMO detector 256, receive processor 258, controller / processor 280, transmit processor 264, TX MIMO processor 266, MOD 254, etc.) may communicate with a synchronization reference source to synchronize a first clock of the wireless communication device with a second clock of the synchronization reference source.

[0066] Process 400 may include additional aspects, such as any single aspect or any combination of aspects described below and / or described in conjunction with one or more other processes described elsewhere herein.

[0067] In a first aspect, selecting a synchronization reference source includes selecting a synchronization reference source based at least in part on determining a plurality of clock accuracy indicators.

[0068] In a second aspect, either alone or in combination with the first aspect, the plurality of available synchronization reference sources include at least one of: a cell of the wireless communication device, another wireless communication device within a coverage area of ​​the wireless communication device, another wireless communication device located outside the coverage area of ​​the wireless communication device and having a clock source synchronized with another wireless communication device within the coverage area of ​​the wireless communication device, or another wireless communication device located outside the coverage area of ​​the wireless communication device and having a clock source synchronized with another wireless communication device outside the wireless communication device.

[0069] In a third aspect, either alone or in combination with the second aspect, a plurality of available synchronization reference sources are ordered based at least in part on corresponding clock accuracies.

[0070] In a fourth aspect, alone or in combination with one or more of the first to third aspects, selecting a synchronization reference source comprises selecting a synchronization reference source based at least in part on at least one of a link capacity or quality threshold or a source capacity threshold.

[0071] In a fifth aspect, alone or in combination with one or more of the first to fourth aspects, process 400 includes setting a clock accuracy indicator of the wireless communication device based at least in part on a clock accuracy indicator of a synchronization reference source.

[0072] In a sixth aspect, alone or in combination with the fifth aspect, the clock accuracy indicator of the wireless communication device indicates the same level of accuracy or a lower level of accuracy than the clock accuracy indicator of the synchronization reference source.

[0073] In a seventh aspect, alone or in combination with one or more of the first to sixth aspects, process 400 includes receiving signaling identifying a clock accuracy indicator of a synchronization reference source, wherein the signaling is conveyed in at least one of: a master information block, a system information block, an RRC message, a MAC-CE, a higher layer protocol control message, a downlink control information, a sidelink control information, a sidelink MAC-CE, or a sidelink RRC message.

[0074] In an eighth aspect, alone or in combination with the seventh aspect, the signaling is received from at least one of a serving base station, a central server, a location management function, a time server, or a user equipment.

[0075] In a ninth aspect, alone or in combination with one or more of the seventh to eighth aspects, the signaling is a synchronization accuracy message identifying a clock accuracy indicator.

[0076] In a tenth aspect, either alone or in combination with one or more of the first to ninth aspects, communicating with a synchronization reference source to synchronize a first clock of the wireless communication device with a second clock of the synchronization reference source includes obtaining one or more measurements associated with one or more RF signals.

[0077] In the eleventh aspect, alone or in combination with one or more of the first to tenth aspects, obtaining one or more measurements includes obtaining one or more measurements according to a synchronization mode, and the synchronization mode includes at least one of RTT synchronization, unidirectional synchronization, or PDP-based synchronization.

[0078] In a twelfth aspect, alone or in combination with the tenth aspect, the one or more measurements include at least one of an RTT measurement, a one-way synchronization measurement, or a PDP measurement.

[0079] In a thirteenth aspect, either alone or in combination with the tenth aspect, process 400 includes determining an earliest common peak associated with a first PDP measurement obtained by a wireless communication device and a second PDP measurement received from a synchronization reference source, and determining a time offset between the wireless communication device and the synchronization reference source based at least in part on determining the earliest common peak.

[0080] In a fourteenth aspect, alone or in combination with the tenth aspect, the one or more radio frequency signals include one or more positioning reference signals.

[0081] In a fifteenth aspect, alone or in combination with the fourteenth aspect, the one or more positioning reference signals include at least one of a downlink positioning reference signal or a sounding reference signal for positioning.

[0082] Although Figure 4 Example blocks of process 400 are shown, but in some aspects, Figure 4 Process 400 may include additional blocks, fewer blocks, different blocks, or differently arranged blocks than those depicted in . Additionally or alternatively, two or more of the blocks of process 400 may be performed in parallel.

[0083] The following provides an overview of certain aspects of the disclosure:

[0084] Aspect 1: A method of wireless communication performed by a wireless communication device, comprising: selecting a synchronization reference source from a plurality of available synchronization reference sources based at least in part on a clock accuracy indicator of the synchronization reference source; and communicating with the synchronization reference source to synchronize a first clock of the wireless communication device with a second clock of the synchronization reference source.

[0085] Aspect 2: The method of aspect 1, further comprising: determining a plurality of clock accuracy indicators of a plurality of available synchronization reference sources; and wherein selecting the synchronization reference source comprises: selecting the synchronization reference source based at least in part on determining the plurality of clock accuracy indicators. wherein selecting the synchronization reference source comprises: selecting the synchronization reference source based at least in part on determining the plurality of clock accuracy indicators.

[0086] Aspect 3: A method as in any of Aspects 1 or 2, wherein the multiple available synchronization reference sources include at least one of: a cell of the wireless communication device, another wireless communication device within the coverage area of ​​the wireless communication device, another wireless communication device located outside the coverage area of ​​the wireless communication device and having a clock source synchronized with another wireless communication device within the coverage area of ​​the wireless communication device, or another wireless communication device located outside the coverage area of ​​the wireless communication device and having a clock source synchronized with another wireless communication device outside the wireless communication device.

[0087] Aspect 4: The method of aspect 3, wherein the plurality of available synchronization reference sources are ordered based at least in part on corresponding clock accuracies.

[0088] Aspect 5: The method of any of aspects 1-4, wherein selecting a synchronization reference source comprises: selecting the synchronization reference source based at least in part on at least one of a link capacity or quality threshold or a source capacity threshold.

[0089] Aspect 6: The method of any of aspects 1-5, further comprising: setting a clock accuracy indicator of the wireless communication device based at least in part on a clock accuracy indicator of the synchronization reference source.

[0090] Aspect 7: The method of aspect 6, wherein the clock accuracy indicator of the wireless communication device indicates the same level of accuracy or a lower level of accuracy than the clock accuracy indicator of the synchronization reference source.

[0091] Aspect 8: The method as in any one of Aspects 1-7 further includes: receiving signaling of a clock accuracy indicator identifying a synchronization reference source, wherein the signaling is conveyed in at least one of the following: a master information block, a system information block, a radio resource control (RRC) message, a medium access control (MAC) control element (MAC-CE), a higher layer protocol control message, a downlink control information, a sidelink control information, a sidelink MAC-CE, or a sidelink RRC message.

[0092] Aspect 9: The method of aspect 8, wherein the signaling is received from at least one of a serving base station, a central server, a location management function, a time server, or a user equipment.

[0093] Aspect 10: The method of any one of Aspects 8 or 9, wherein the signaling is a synchronization accuracy message identifying a clock accuracy indicator.

[0094] Aspect 11: The method of any of Aspects 1-10, wherein communicating with a synchronization reference source to synchronize a first clock of the wireless communication device with a second clock of the synchronization reference source comprises obtaining one or more measurements associated with one or more radio frequency signals.

[0095] Aspect 12: A method as in any of Aspects 1-11, wherein performing one or more measurements comprises performing one or more measurements according to a synchronization mode, wherein the synchronization mode comprises at least one of the following: round-trip time synchronization, unidirectional synchronization, or power delay profile based synchronization.

[0096] Aspect 13: The method of aspect 11, wherein the one or more measurements include at least one of the following: a round trip time measurement, a one-way synchronization measurement, or a power delay profile measurement.

[0097] Aspect 14: The method of Aspect 11 also includes determining an earliest common peak associated with a first power delay profile (PDP) measurement obtained by the wireless communication device and a second PDP measurement received from a synchronization reference source; and determining a time offset between the wireless communication device and the synchronization reference source based at least in part on determining the earliest common peak.

[0098] Aspect 15: The method of aspect 11, wherein the one or more radio frequency signals include one or more positioning reference signals.

[0099] Aspect 16: The method of aspect 15, wherein the one or more positioning reference signals include at least one of a downlink positioning reference signal or a sounding reference signal for positioning.

[0100] Aspect 17: An apparatus for wireless communication at a device, comprising a processor; a memory coupled to the processor; and instructions stored in the memory and executable by the processor to cause the apparatus to perform the method of one or more aspects of aspects 1-16.

[0101] Aspect 18: A device for wireless communication, comprising a memory and one or more processors coupled to the memory, the memory and the one or more processors being configured to perform the method of one or more aspects of aspects 1-16.

[0102] Aspect 19: An apparatus for wireless communication, comprising at least one component for performing the method of one or more of aspects 1-16.

[0103] Aspect 20: A non-transitory computer-readable medium storing code for wireless communication, the code comprising instructions executable by a processor to perform the method of one or more aspects of aspects 1-16.

[0104] Aspect 21: A non-transitory computer-readable medium storing an instruction set for wireless communication, the instruction set comprising one or more instructions that, when executed by one or more processors of a device, cause the device to perform the method of one or more aspects of aspects 1-16.

[0105] The foregoing disclosure provides illustration and description, but is not intended to be exhaustive or to limit the aspects to the precise forms disclosed. Modifications and variations may be made in light of the above disclosure or may be acquired from practice of the aspects.

[0106] As used herein, the term "component" is intended to be broadly interpreted as a combination of hardware and / or hardware and software. "Software" should be broadly interpreted as meaning instructions, instruction sets, codes, code segments, program codes, programs, subroutines, software modules, applications, software applications, software packages, routines, subroutines, objects, executable files, execution threads, processes and / or functions, etc., whether referred to as software, firmware, middleware, microcode, hardware description language or other. As used herein, the processor is implemented in a combination of hardware and / or hardware and software. It will be apparent that the system and / or method described herein can be implemented in a combination of hardware and / or hardware and software in different forms. The actual dedicated control hardware or software code for implementing these systems and / or methods is not a limitation of aspect. Therefore, the operation and behavior of the system and / or method are described herein without reference to specific software codes--it should be understood that software and hardware can be designed to realize the system and / or method based at least in part on the description of this article.

[0107] As used herein, satisfying a threshold may refer to a value being greater than a threshold, greater than or equal to a threshold, less than a threshold, less than or equal to a threshold, equal to a threshold, not equal to a threshold, etc., depending on the context.

[0108] Even if the specific combination of features is stated in the claims and / or disclosed in the specification, these combinations are not intended to limit the disclosure of various aspects. In fact, many of these features can be combined in a manner not specifically stated in the claims and / or disclosed in the specification. Although each dependent claim listed below can directly rely on only one claim, the disclosure of various aspects includes that each dependent claim is combined with each other claim in the claim set. As used herein, the phrase "at least one" in the list of reference items refers to any combination of those items, including single members. As an example, "at least one of a, b or c" is intended to cover a, b, c, ab, ac, bc and abc, and any combination with multiple identical elements (for example, aa, aaa, aab, aac, abb, acc, bb, bbb, bbc, cc and ccc or any other order of a, b and c).

[0109] Elements, actions or instructions used herein should not be interpreted as critical or necessary, unless clearly described as such. Likewise, as used herein, the articles "a" and "an" are intended to include one or more items, and can be used interchangeably with "one or more". In addition, as used herein, the article "the" is intended to include one or more items quoted in conjunction with the article "the", and can be used interchangeably with "one or more". In addition, as used herein, the term "set" and "group" are intended to include one or more items (for example, related items, unrelated items, or a combination of related and unrelated items), and can be used interchangeably with "one or more". In the case of only meaning an item, phrases "only one" or similar language are used. Likewise, as used herein, the terms "has", "have", "with", etc. are intended to be open terms. In addition, the phrase "based on" is intended to mean "based at least in part", unless otherwise clearly stated. Likewise, as used herein, the term "or" when used in a series is intended to be inclusive and may be used interchangeably with "and / or" unless expressly stated otherwise (e.g., if used in conjunction with "either" or "only one of...").

Claims

1. A wireless communication device for wireless communication, comprising: Memory; as well as one or more processors, the one or more processors operably coupled to the memory, configured to: selecting a synchronization reference source from a plurality of available synchronization reference sources based at least in part on a clock accuracy indicator of the synchronization reference source; setting a clock accuracy indicator of the wireless communication device based at least in part on the clock accuracy indicator of the synchronization reference source; as well as Communicate with the synchronization reference source to synchronize a first clock of the wireless communication device with a second clock of the synchronization reference source, wherein the clock accuracy indicator of the wireless communication device indicates the same level of accuracy as or a lower level of accuracy than the clock accuracy indicator of the synchronization reference source.

2. The wireless communication device of claim 1 , wherein the one or more processors are further configured to: determining a plurality of clock accuracy indicators for the plurality of available synchronization reference sources; and Wherein, in order to select the synchronization reference source, the one or more processors are configured to: The synchronization reference source is selected based at least in part on determining the plurality of clock accuracy indicators.

3. The wireless communication device of claim 1 , wherein the plurality of available synchronization reference sources comprises at least one of: a cell of the wireless communication device, another wireless communication device within the coverage area of ​​the wireless communication device, another wireless communication device located outside the coverage area of ​​the wireless communication device and having a clock source synchronized with another wireless communication device within the coverage area of ​​the wireless communication device, or Another wireless communication device located outside the coverage area of ​​the wireless communication device and having a clock source synchronized with another wireless communication device other than the wireless communication device.

4. The wireless communication device of claim 3, wherein the plurality of available synchronization reference sources are ordered based at least in part on corresponding clock accuracies.

5. The wireless communication device of claim 1 , wherein to select the synchronization reference source, the one or more processors are configured to: The synchronization reference source is selected based at least in part on at least one of a link capacity or quality threshold or a source capacity threshold.

6. The wireless communication device of claim 1, wherein the one or more processors are further configured to: receiving signaling identifying the clock accuracy indicator of the synchronization reference source, wherein the signaling is conveyed in at least one of: Main information block, System Information Block, Radio Resource Control RRC messages, Medium Access Control MAC Control Element MAC CE, Higher layer protocol control messages, Downlink control information, Sidelink control information, Sidelink MAC CE, or Sidelink RRC message.

7. The wireless communication device of claim 6, wherein the signaling is received from at least one of a serving base station, a central server, a location management function, a time server, or a user equipment.

8. The wireless communication device of claim 6, wherein the signaling is a synchronization accuracy message identifying the clock accuracy indicator.

9. A wireless communication device as described in claim 1, wherein in order to communicate with the synchronization reference source to synchronize the first clock of the wireless communication device with the second clock of the synchronization reference source, the one or more processors are configured to obtain one or more measurements associated with one or more radio frequency signals.

10. The wireless communication device of claim 9, wherein the one or more processors are configured to obtain the one or more measurements according to a synchronization pattern, wherein the synchronization pattern comprises at least one of: Round trip time synchronization, One-way synchronization, or Synchronization based on power-delay profile.

11. The wireless communication device of claim 9, wherein the one or more measurements include at least one of: Round trip time measurement, One-way simultaneous measurement, or Power delay profile measurement.

12. A wireless communication device as described in claim 9, wherein the one or more processors are configured to determine a time offset between the wireless communication device and the synchronization reference source based at least in part on determining an earliest common peak associated with a first power delay profile (PDP) measurement obtained by the wireless communication device and a second PDP measurement received from the synchronization reference source.

13. The wireless communication device of claim 9, wherein the one or more radio frequency signals include one or more positioning reference signals.

14. The wireless communication device of claim 13, wherein the one or more positioning reference signals comprise at least one of a downlink positioning reference signal or a sounding reference signal for positioning.

15. A method of wireless communication performed by a wireless communication device, comprising: selecting a synchronization reference source from a plurality of available synchronization reference sources based at least in part on a clock accuracy indicator of the synchronization reference source; setting a clock accuracy indicator of the wireless communication device based at least in part on the clock accuracy indicator of the synchronization reference source; as well as Communicate with the synchronization reference source to synchronize a first clock of the wireless communication device with a second clock of the synchronization reference source, wherein the clock accuracy indicator of the wireless communication device indicates the same level of accuracy as or a lower level of accuracy than the clock accuracy indicator of the synchronization reference source.

16. The method of claim 15, further comprising: determining a plurality of clock accuracy indicators for the plurality of available synchronization reference sources; and Wherein selecting the synchronization reference source comprises: The synchronization reference source is selected based at least in part on determining the plurality of clock accuracy indicators.

17. The method of claim 15, wherein the plurality of available synchronization reference sources comprises at least one of: a cell of the wireless communication device, another wireless communication device within the coverage area of ​​the wireless communication device, another wireless communication device located outside the coverage area of ​​the wireless communication device and having a clock source synchronized with another wireless communication device within the coverage area of ​​the wireless communication device, or Another wireless communication device located outside the coverage area of ​​the wireless communication device and having a clock source synchronized with another wireless communication device other than the wireless communication device.

18. The method of claim 17, wherein the plurality of available synchronization reference sources are ordered based at least in part on corresponding clock accuracies.

19. The method of claim 15, wherein selecting the synchronization reference source comprises: The synchronization reference source is selected based at least in part on at least one of a link capacity or quality threshold or a source capacity threshold.

20. The method of claim 15, further comprising: receiving signaling identifying the clock accuracy indicator of the synchronization reference source, wherein the signaling is conveyed in at least one of: Main information block, System Information Block, Radio Resource Control RRC messages, Medium Access Control MAC Control Element MAC CE, Higher layer protocol control messages, Downlink control information, Sidelink control information, Sidelink MAC CE, or Sidelink RRC message.

21. The method of claim 20, wherein the signaling is received from at least one of a serving base station, a central server, a location management function, a time server, or a user equipment.

22. The method of claim 20, wherein the signaling is a synchronization accuracy message identifying the clock accuracy indicator.

23. The method of claim 15, wherein communicating with the synchronization reference source to synchronize the first clock of the wireless communication device with the second clock of the synchronization reference source comprises obtaining one or more measurements associated with one or more radio frequency signals.

24. The method of claim 23, wherein obtaining the one or more measurements comprises obtaining the one or more measurements according to a synchronization pattern, wherein the synchronization pattern comprises at least one of: Round trip time synchronization, One-way synchronization, or Synchronization based on power-delay profile.

25. The method of claim 23, wherein the one or more measurements include at least one of: Round trip time measurement, One-way simultaneous measurement, or Power delay profile measurement.

26. The method of claim 23, further comprising: determining an earliest common peak value associated with a first power delay profile (PDP) measurement obtained by the wireless communication device and a second PDP measurement received from the synchronization reference source; as well as A time offset between the wireless communication device and the synchronization reference source is determined based at least in part on determining the earliest common peak.

27. A non-transitory computer readable medium storing a set of instructions for wireless communication, the set of instructions comprising: One or more instructions that, when executed by one or more processors of a wireless communication device, cause the wireless communication device to: selecting a synchronization reference source from a plurality of available synchronization reference sources based at least in part on a clock accuracy indicator of the synchronization reference source; setting a clock accuracy indicator of the wireless communication device based at least in part on the clock accuracy indicator of the synchronization reference source; as well as Communicate with the synchronization reference source to synchronize a first clock of the wireless communication device with a second clock of the synchronization reference source, wherein the clock accuracy indicator of the wireless communication device indicates the same level of accuracy as or a lower level of accuracy than the clock accuracy indicator of the synchronization reference source.

28. An apparatus for wireless communication, comprising: means for selecting a synchronization reference source from a plurality of available synchronization reference sources based at least in part on a clock accuracy indicator of the synchronization reference source; means for setting a clock accuracy indicator of the wireless communication device based at least in part on the clock accuracy indicator of the synchronization reference source; as well as means for communicating with the synchronization reference source to synchronize a first clock of the apparatus with a second clock of the synchronization reference source, wherein the clock accuracy indicator of the wireless communication device indicates the same level of accuracy as or a lower level of accuracy than the clock accuracy indicator of the synchronization reference source.

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