Reference timing delivery with propagation delay compensation to user equipment

Abstract

A wireless communication system is provided that allows a base station to indicate RTT compensation for a UE to adjust its local clock to correct the propagation delay timing error and synchronize with the global clock of the base station. The base station sends a downlink transmission including timing information to the UE and receives an uplink transmission from the UE after the downlink transmission. The base station determines the RTT compensation associated with the timing information based on the RTT between the downlink transmission and the uplink transmission. The base station then transmits the RTT compensation to the UE. The UE is thereby allowed to synchronize with the clock of the base station with high accuracy. The UE can be configured with different resolutions or granularities in the timing correction so that some UEs can achieve high-precision timing correction, while other UEs can adjust their clocks with lower accuracy.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of U.S. Provisional Application No. 62 / 829,545, filed on April 4, 2019, entitled “REFERENCE TIMING DELIVERY TO USER EQUIPMENT WITH PROPAGATION DELAY COMPENSATION,” and U.S. Patent Application No. 16 / 836,543, filed on March 31, 2020, entitled “REFERENCE TIMING DELIVERY TO USER EQUIPMENT WITH PROPAGATION DELAY COMPENSATION,” both of which are expressly incorporated herein by reference in their entirety.

[0003] background Technical Field

[0005] The present disclosure relates generally to communication systems, and more particularly to wireless communication systems between base stations and user equipment (UE).

[0006] introduction

[0007] Wireless communication systems are widely deployed to provide various telecommunication services such as telephony, video, data, messaging, and broadcast. Typical wireless communication systems may employ multiple access technologies capable of supporting communication with multiple users by sharing available system resources. Examples of such multiple access technologies 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.

[0008] These multiple access technologies have been adopted in various telecommunication standards to provide common protocols that enable different wireless devices to communicate at city, country, region, and even global levels. An example telecommunication standard is 5G New Radio (NR). 5G NR is a part of the continuous mobile broadband evolution promulgated by the Third Generation Partnership Project (3GPP) to meet new requirements associated with latency, reliability, security, scalability (e.g., with the Internet of Things (IoT)) and other requirements. 5GNR includes services associated with enhanced mobile broadband (eMBB), massive machine type communication (mMTC), and ultra-reliable low latency communication (URLLC). Some aspects of 5G NR can be based on 4G Long Term Evolution (LTE) standards. There is a need for further improvements to 5G NR technology. These improvements can also be applied to other multiple access technologies and telecommunication standards that employ these technologies.

[0009] Overview

[0010] A brief summary of one or more aspects is given below to provide a basic understanding of such aspects. This summary is not an exhaustive overview of all conceived aspects, and is neither intended to identify the key or critical elements of all aspects nor to define the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form as a prelude to a more detailed description that will be presented later.

[0011] The Internet of Things (IoT) allows devices such as UEs to receive, process, and analyze data from a network of other interconnected computing devices in various consumer and industrial applications (e.g., telecommunications, automotive, energy, health care, etc.). Especially in the Industrial IoT (IIoT), where the UEs may be located in refineries, power plants, hospitals, etc. and control their processes, time synchronization between devices is very important. For example, multiple IIoT UEs may communicate with a base station to monitor a patient's vital signs, etc. If the downlink / uplink subframe timing is not accurately synchronized at the base station and the UE, interference may occur and / or necessary data may be lost.

[0012] Therefore, in order to accurately synchronize the timing between the base station and the 5G-capable IIOT UE, the base station can send timing information (e.g., clock) to the UE based on IEEE1588v2 / Precision Time Protocol. However, according to this protocol, the base station can send timing information (e.g., clock) to the UE at a distance of less than 20 km. 2Within the service area, the UE's operating clock domain must be synchronized to within ≤1μs with the global clock of the base station (e.g., synchronization master). Such service area conditions typically exist in outdoor macro network deployments, where the UE may be hundreds of meters away from the base station and the propagation delay of the transmission may be large (e.g., 3μs / km). Since such a large propagation delay can naturally offset the timing between the base station and the UE by more than 1μs, round-trip time (RTT) compensation or propagation delay correction for timing synchronization between the base station and the UE may be required. Although timing synchronization based on the Global Positioning System (GPS) provides an alternative to IEEE1588v2 / Precision Time Protocol, 5G has an advantage because it provides a unified system for data communication and timing.

[0013] Therefore, a solution is needed that allows a base station to deliver timing information to a UE in an outdoor scenario while taking RTT compensation into account to meet the ≤1μs synchronization accuracy parameter of the IEEE1588v2 / Precision Time Protocol. It is also necessary to provide this solution for certain UEs (e.g., IIOT UEs) while allowing other UEs (e.g., non-IIOT UEs or legacy UEs) to continue to observe lower precision timing synchronization parameters.

[0014] The present disclosure provides a solution to these needs by allowing the base station to indicate RTT compensation for the UE to use in adjusting its individual or local clock, thereby allowing the UE to synchronize with the base station's clock with high accuracy. The present disclosure also allows the UE to be configured with different resolutions or granularities in timing correction so that some UEs can achieve high-precision timing correction, while other UEs can adjust their clocks with lower accuracy. In this way, the base station can deliver timing information to the UE in an outdoor scenario while taking RTT compensation into account to meet the IEEE1588v2 / Precision Time Protocol's synchronization accuracy parameter of ≤1μs. In addition, some UEs (e.g., IIOT UEs) can obtain higher accuracy for timing correction, while other UEs (e.g., non-IIOT UEs or legacy UEs) can observe lower-precision timing synchronization parameters.

[0015] In one aspect of the present disclosure, a method, a computer-readable medium, and an apparatus are provided. The apparatus may be a base station. In various aspects, the base station sends a downlink transmission including timing information to a UE and receives an uplink transmission from the UE after the downlink transmission. The base station then determines an RTT compensation associated with the timing information based on the RTT between the downlink transmission and the uplink transmission. The base station then transmits the RTT compensation to the UE.

[0016] In another aspect of the present disclosure, a method, a computer-readable medium, and a device are provided. The device may be a UE. In various aspects, the UE receives a downlink transmission including timing information from a base station. The UE sends an uplink transmission to the base station after the downlink transmission, and obtains RTT compensation for the timing information based on the RTT between the downlink transmission and the uplink transmission.

[0017] To achieve the foregoing and related ends, the one or more aspects include the features fully described below and particularly pointed out in the claims. The following description and drawings set forth in detail certain illustrative features of the one or more aspects. However, these features are merely indicative of several of the various ways in which the principles of the various aspects may be employed, and this description is intended to cover all such aspects and their equivalents. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is a diagram illustrating an example of a wireless communication system and an access network.

[0020] Figure 2A , 2B , 2C, and 2D are diagrams illustrating examples of a first 5G / NR frame, a DL channel within a 5G / NR subframe, a second 5G / NR frame, and a UL channel within a 5G / NR subframe, respectively.

[0021] Figure 3 is a diagram illustrating an example of a base station and a user equipment (UE) in an access network.

[0022] Figure 4 is a diagram illustrating an example communication flow of timing information from one or more base stations to a UE.

[0023] Figure 5 are diagrams illustrating examples of transmission frames transmitted by a base station and received by a UE, respectively.

[0024] Figure 6 is a diagram illustrating various timelines for downlink and uplink transmissions between a base station and a UE.

[0025] Fig. 7A and 7B are diagrams illustrating different examples of frame structures in which a base station may provide a timing advance command to a UE.

[0026] Figure 8 is a diagram illustrating an example communication flow between a base station and a UE.

[0027] Fig. 9 is a flow chart of a wireless communication method at a base station.

[0028] Fig.10is a conceptual data flow diagram illustrating the flow of data between different devices / components in an example base station apparatus.

[0029] Fig.11 is a diagram illustrating an example of a hardware implementation of a base station device employing a processing system.

[0030] Fig.12 is a flow chart of a wireless communication method at a UE.

[0031] Fig.13 is a conceptual data flow diagram illustrating the flow of data between different devices / components in an example UE apparatus.

[0032] Fig.14 is a diagram illustrating an example of a hardware implementation for a UE device employing a processing system.

[0033] Detailed Description

[0034] The detailed description set forth below in conjunction with the accompanying drawings is intended as a description of various configurations and is not intended to represent the only configurations in which the concepts described herein may be practiced. This detailed description includes specific details to provide a thorough understanding of the various concepts. However, it will be apparent to those skilled in the art that these concepts may be practiced without these specific details. In some instances, well-known structures and components are shown in block diagram form in order to avoid diluting such concepts.

[0035] Several aspects of telecommunication systems will now be presented with reference to various devices and methods. These devices and methods will be described in the following detailed description and illustrated in the accompanying drawings by various blocks, components, circuits, processes, algorithms, etc. (collectively referred to as "elements"). These elements can be implemented using electronic hardware, computer software, or any 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.

[0036] As an example, an element, or any part of an element, or any combination of elements may be implemented as a "processing system" including one or more processors. Examples of processors include: microprocessors, microcontrollers, graphics processing units (GPUs), central processing units (CPUs), application processors, digital signal processors (DSPs), reduced instruction set computing (RISC) processors, systems on chip (SoCs), baseband processors, field programmable gate arrays (FPGAs), programmable logic devices (PLDs), state machines, gating logic, discrete hardware circuits, and other suitable hardware configured to perform various functionalities described throughout this disclosure. One or more processors in a processing system may execute software. Software should be broadly interpreted as meaning instructions, instruction sets, codes, code segments, program codes, programs, subroutines, software components, applications, software applications, software packages, routines, subroutines, objects, executables, threads of execution, procedures, functions, etc., whether it is described in software, firmware, middleware, microcode, hardware description languages, or other terms.

[0037] Accordingly, in one or more example embodiments, the functions described may be implemented in hardware, software, or any combination thereof. If implemented in software, each function may be stored or encoded on a computer-readable medium as one or more instructions or codes. Computer-readable media include computer storage media. Storage media may be any available medium that can be accessed by a computer. As an example and not limitation, such computer-readable media may include random access memory (RAM), read-only memory (ROM), electrically erasable programmable ROM (EEPROM), optical disk storage, magnetic disk storage, other magnetic storage devices, a combination of computer-readable media of the above types, or any other medium that can be used to store computer-executable code in the form of instructions or data structures that can be accessed by a computer.

[0038] Figure 1 1 is a diagram illustrating an example of a wireless communication system and access network 100. The wireless communication system (also referred to as a wireless wide area network (WWAN)) includes a base station 102, a user equipment (UE) 104, an evolved packet core (EPC) 160, and another core network 190 (e.g., a 5G core (5GC)). The base station 102 may include a macro cell (a high-power cellular base station) and / or a small cell (a low-power cellular base station). A macro cell includes a base station. A small cell includes a femto cell, a pico cell, and a micro cell.

[0039] The base station 102 configured for 4G Long Term Evolution (LTE), collectively referred to as the Evolved Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network (E-UTRAN), can interface with the EPC 160 via a first backhaul link 132 (e.g., an S1 interface). The base station 102 configured for 5G New Radio (NR), collectively referred to as the Next Generation RAN (NG-RAN), can interface with the core network 190 via a second backhaul link 184. The base station 102 can also perform one or more of the following functions, among other functions: delivery of user data, radio channel encryption and decryption, integrity protection, header compression, mobility control functions (e.g., handover, dual connectivity), inter-cell interference coordination, connection establishment and release, load balancing, distribution of non-access stratum (NAS) messages, NAS node selection, synchronization, radio access network (RAN) sharing, multimedia broadcast multicast service (MBMS), subscriber and equipment tracking, RAN information management (RIM), paging, positioning, and delivery of alert messages. The base stations 102 may communicate with each other directly or indirectly (eg, through the EPC 160 or the core network 190) over a third backhaul link 134 (eg, an X2 interface). The third backhaul link 134 may be wired or wireless.

[0040] Base stations 102 may communicate wirelessly with UE 104. Each base station 102 may provide communication coverage for a corresponding geographic coverage area 110. There may be overlapping geographic coverage areas 110. For example, a small cell 102' may have a coverage area 110' that overlaps with the coverage area 110 of one or more macro base stations 102. A network including both small cells and macro cells may be referred to as a heterogeneous network. A heterogeneous network may also include a home evolved B node (eNB) (HeNB), which may provide services to a restricted group referred to as a closed subscriber group (CSG). A communication link 120 between a base station 102 and a UE 104 may include an uplink (UL) (also referred to as a reverse link) transmission from the UE 104 to the base station 102 and / or a downlink (DL) (also referred to as a forward link) transmission from the base station 102 to the UE 104. The communication link 120 may use multiple input multiple output (MIMO) antenna technology, including spatial multiplexing, beamforming and / or transmit diversity. These communication links may be through one or more carriers. The base station 102 / UE 104 may use spectrum of up to Y MHz (e.g., 5, 10, 15, 20, 100, 400 MHz, etc.) bandwidth for each carrier allocated in the carrier aggregation for a total of up to Yx MHz (x component carriers) for transmission in each direction. The carriers may or may not be adjacent to each other. The allocation of carriers may be asymmetric with respect to DL and UL (e.g., more or fewer carriers may be allocated to DL compared to UL). The component carriers may include a primary component carrier and one or more secondary component carriers. The primary component carrier may be referred to as a primary cell (PCell) and the secondary component carrier may be referred to as a secondary cell (SCell).

[0041] Some UEs 104 may communicate with each other using a device-to-device (D2D) communication link 158. The D2D communication link 158 may use DL / UL WWAN spectrum. The D2D communication link 158 may use one or more sidelink channels, such as a physical sidelink broadcast channel (PSBCH), a physical sidelink discovery channel (PSDCH), a physical sidelink shared channel (PSSCH), and a physical sidelink control channel (PSCCH). The D2D communication may be through a variety of wireless D2D communication systems, such as, for example, FlashLinQ, WiMedia, Bluetooth, ZigBee, Wi-Fi based on the IEEE 802.11 standard, LTE, or NR.

[0042] The wireless communication system may further include a Wi-Fi access point (AP) 150 communicating with a Wi-Fi station (STA) 152 in the 5 GHz unlicensed spectrum via a communication link 154. When communicating in the unlicensed spectrum, the STA 152 / AP 150 may perform a clear channel assessment (CCA) prior to communication to determine whether the channel is available.

[0043] The small cell 102' may operate in a licensed and / or unlicensed spectrum. When operating in an unlicensed spectrum, the small cell 102' may employ NR and use the same 5 GHz unlicensed spectrum as used by the Wi-Fi AP 150. The small cell 102' employing NR in the unlicensed spectrum may boost the coverage of the access network and / or increase the capacity of the access network.

[0044] Whether a small cell 102' or a large cell (e.g., a macro base station), the base station 102 may include and / or be referred to as an eNB, a gNodeB (gNB), or another type of base station. Some base stations (such as gNB 180) may operate in traditional sub-6 GHz spectrum, millimeter wave (mmW) frequencies, and / or near mmW frequencies to communicate with UE 104. When the gNB 180 operates in mmW or near mmW frequencies, the gNB 180 may be referred to as a mmW base station. Extremely high frequency (EHF) is part of the RF in the electromagnetic spectrum. EHF has a range of 30 GHz to 300 GHz and a wavelength between 1 mm and 10 mm. The radio waves in this band may be referred to as millimeter waves. Near mmW can be extended down to 3 GHz frequencies with a wavelength of 100 mm. The super high frequency (SHF) band extends between 3 GHz and 30 GHz, which is also referred to as centimeter waves. Communications using mmW / near mmW radio frequency bands (e.g., 3 GHz–300 GHz) have extremely high path loss and short range. The mmW base station 180 may utilize beamforming 182 with the UE 104 to compensate for the extremely high path loss and short range. The base station 180 and the UE 104 may each include multiple antennas, such as antenna elements, antenna panels, and / or antenna arrays to facilitate beamforming.

[0045] Base station 180 may transmit beamformed signals to UE 104 in one or more transmit directions 182'. UE 104 may receive beamformed signals from base station 180 in one or more receive directions 182". UE 104 may also transmit beamformed signals to base station 180 in one or more transmit directions. Base station 180 may receive beamformed signals from UE 104 in one or more receive directions. Base station 180 / UE 104 may perform beam training to determine the best receive direction and transmit direction for each of base station 180 / UE 104. The transmit direction and receive direction of base station 180 may be the same or may be different. The transmit direction and receive direction of UE 104 may be the same or may be different.

[0046] The EPC 160 may include a mobility management entity (MME) 162, other MMEs 164, a serving gateway 166, a multimedia broadcast multicast service (MBMS) gateway 168, a broadcast multicast service center (BM-SC) 170, and a packet data network (PDN) gateway 172. The MME 162 may be in communication with a home subscriber server (HSS) 174. The MME 162 is a control node that handles signaling between the UE 104 and the EPC 160. In general, the MME 162 provides bearer and connection management. All user Internet Protocol (IP) packets are delivered through the serving gateway 166, which itself is connected to the PDN gateway 172. The PDN gateway 172 provides UE IP address allocation and other functions. The PDN gateway 172 and the BM-SC 170 are connected to IP services 176. The IP services 176 may include the Internet, an intranet, an IP multimedia subsystem (IMS), a PS streaming service, and / or other IP services. The BM-SC 170 may provide functionality for MBMS user service provisioning and delivery. The BM-SC 170 may serve as an entry point for content provider MBMS transmissions, may be used to authorize and initiate MBMS bearer services within a public land mobile network (PLMN), and may be used to schedule MBMS transmissions. The MBMS gateway 168 may be used to distribute MBMS traffic to base stations 102 belonging to a multicast broadcast single frequency network (MBSFN) area that broadcasts a specific service, and may be responsible for session management (start / stop) and for collecting eMBMS-related charging information.

[0047] The core network 190 may include an access and mobility management function (AMF) 192, other AMFs 193, a session management function (SMF) 194, and a user plane function (UPF) 195. The AMF 192 may be in communication with a unified data management (UDM) 196. The AMF 192 is a control node that handles signaling between the UE 104 and the core network 190. In general, the AMF 192 provides QoS flow and session management. All user Internet Protocol (IP) packets are delivered through the UPF 195. The UPF 195 provides UE IP address allocation and other functions. The UPF 195 is connected to an IP service 197. The IP service 197 may include the Internet, an intranet, an IP multimedia subsystem (IMS), a PS streaming service, and / or other IP services.

[0048] A base station may include and / or be referred to as a gNB, a Node B, an eNB, an access point, a base transceiver station, a radio base station, a radio transceiver, a transceiver function, a basic service set (BSS), an extended service set (ESS), a transmission reception point (TRP), or some other suitable term. The base station 102 provides an access point to the EPC 160 or the core network 190 for the UE 104. Examples of UE 104 include a cellular phone, a smart phone, a Session Initiation Protocol (SIP) phone, a laptop, a personal digital assistant (PDA), a satellite radio, a global positioning system, a multimedia device, a video device, a digital audio player (e.g., an MP3 player), a camera, a game console, a tablet device, a smart device, a wearable device, a vehicle, an electric meter, a gas pump, a large or small kitchen appliance, a health care device, an implant, a sensor / actuator, a display, or any other similar functional device. Some UEs 104 may be referred to as Internet of Things (IoT) devices (e.g., parking meters, gas pumps, ovens, vehicles, heart monitors, etc.). UE 104 may also be referred to as a station, a mobile station, a subscriber station, a mobile unit, a subscriber unit, a wireless unit, a remote unit, a mobile device, a wireless device, a wireless communication device, a remote device, a mobile subscriber station, an access terminal, a mobile terminal, a wireless terminal, a remote terminal, a handset, a user agent, a mobile client, a client, or some other suitable terminology.

[0049] Although the present disclosure may focus on 5G NR, the concepts and aspects described herein may be applicable to other similar areas such as LTE, Advanced LTE (LTE-A), Code Division Multiple Access (CDMA), Global System for Mobile Communications (GSM), or other wireless / radio access technologies.

[0050] Refer again Figure 1In certain aspects, the base station 102 / 180 may include an RTT compensation base station component 198 configured to send a downlink transmission including timing information to the UE 104. At the base station 102 / 180, the RTT compensation base station component 198 may be further configured to receive an uplink transmission from the UE 104 after the downlink transmission. In addition, the RTT compensation base station component 198 may be further configured to determine a round trip time (RTT) compensation associated with the timing information based on the RTT between the downlink transmission and the uplink transmission. The RTT compensation base station component 198 may be further configured to transmit the RTT compensation to the UE 104.

[0051] In certain other aspects, the UE 104 may include an RTT compensation UE component 199 configured to receive a downlink transmission including timing information from the base station 102 / 180. At the UE 104, the RTT compensation UE component 199 may be further configured to send an uplink transmission to the base station 102 / 180 after the downlink transmission. In addition, the RTT compensation UE component 199 may be configured to obtain RTT compensation for the timing information based on the RTT between the downlink transmission and the uplink transmission.

[0052] Figure 2A 200 is a diagram illustrating an example of a first subframe within a 5G / NR frame structure. Figure 2B FIG230 is a diagram illustrating an example of DL channels within a 5G / NR subframe. Figure 2C 250 is a diagram illustrating an example of a second subframe within a 5G / NR frame structure. Figure 2D 280 is a diagram illustrating an example of an UL channel within a 5G / NR subframe. The 5G / NR frame structure may be FDD, where for a particular set of subcarriers (carrier system bandwidth), subframes within that subcarrier set are dedicated to either DL or UL, or TDD, where for a particular set of subcarriers (carrier system bandwidth), subframes within that subcarrier set are dedicated to both DL and UL. Figure 2A , 2CIn the example provided, the 5G / NR frame structure is assumed to be TDD, where subframe 4 is configured with slot format 28 (mostly DL) and subframe 3 is configured with slot format 34 (mostly UL), where D is DL, U is UL, and X is for flexible use between DL / UL. Although subframes 3 and 4 are shown as having slot formats 34 and 28, respectively, any particular subframe may be configured with any of the various available slot formats 0-61. Slot formats 0 and 1 are full DL and full UL, respectively. Other slot formats 2-61 include a mixture of DL, UL, and flexible symbols. The UE is configured with a slot format (dynamically configured by DL control information (DCI) or semi-statically / statically configured by radio resource control (RRC) signaling) through the received slot format indicator (SFI). Note that the following description also applies to the 5G / NR frame structure for TDD.

[0053] Other wireless communication technologies may have different frame structures and / or different channels. A frame (10ms) may be divided into 10 equally sized subframes (1ms). Each subframe may include one or more time slots. A subframe may also include mini-slots, which may include 7, 4, or 2 symbols. Each time slot may include 7 or 14 symbols, depending on the time slot configuration. For time slot configuration 0, each time slot may include 14 symbols, and for time slot configuration 1, each time slot may include 7 symbols. The symbols on the DL may be cyclic prefix (CP) OFDM (CP-OFDM) symbols. The symbols on the UL may be CP-OFDM symbols (for high throughput scenarios) or discrete Fourier transform (DFT) spread OFDM (DFT-s-OFDM) symbols (also known as single carrier frequency division multiple access (SC-FDMA) symbols) (for power-limited scenarios; limited to single stream transmission). The number of time slots within a subframe is based on the time slot configuration and parameter design. For slot configuration 0, different parameter designs μ0 to 5 allow 1, 2, 4, 8, 16, and 32 slots per subframe, respectively. For slot configuration 1, different parameter designs 0 to 2 allow 2, 4, and 8 slots per subframe, respectively. Accordingly, for slot configuration 0 and parameter design μ, there are 14 symbols per slot and 2 per subframe. μ time slots. The subcarrier spacing and symbol length / duration vary depending on parameter design. The subcarrier spacing can be equal to 2 μ *15kHz, where μ is parameter design 0 to 5. Thus, parameter design μ=0 has a subcarrier spacing of 15kHz, while parameter design μ=5 has a subcarrier spacing of 480kHz. The symbol length / duration is inversely related to the subcarrier spacing. Figures 2A-2D An example of slot configuration 0 with 14 symbols per slot and parameter design μ=2 and 4 slots per subframe is provided. The slot duration is 0.25 ms, the subcarrier spacing is 60 kHz, and the symbol duration is approximately 16.67 μs.

[0054] A resource grid may be used to represent the frame structure. Each slot includes a resource block (RB) (also called a physical RB (PRB)) extending over 12 consecutive subcarriers. The resource grid is divided into a number of resource elements (REs). The number of bits carried by each RE depends on the modulation scheme.

[0055] like Figure 2A As explained in the illustration, some REs carry reference (pilot) signals (RS) for UEs. RSs may include demodulation RSs (DM-RSs) for channel estimation at the UE (indicated as R for a particular configuration). x , where 100x is the port number, but other DM-RS configurations are possible) and a channel state information reference signal (CSI-RS). RS may also include a beam measurement RS (BRS), a beam refinement RS (BRRS), and a phase tracking RS (PT-RS).

[0056] Figure 2B An example of various DL channels within a subframe of an explanation frame. The physical downlink control channel (PDCCH) carries DCI within one or more control channel elements (CCEs), each CCE includes 9 RE groups (REGs), and each REG includes 4 consecutive REs in an OFDM symbol. The primary synchronization signal (PSS) may be within symbol 2 of a particular subframe of a frame. The PSS is used by the UE 104 to determine the subframe / symbol timing and the physical layer identity. The secondary synchronization signal (SSS) may be within symbol 4 of a particular subframe of a frame. The SSS is used by the UE to determine the physical layer cell identity group number and the radio frame timing. Based on the physical layer identity and the physical layer cell identity group number, the UE may determine the physical cell identifier (PCI). Based on the PCI, the UE may determine the location of the aforementioned DM-RS. The physical broadcast channel (PBCH) carrying the master information block (MIB) may be logically grouped with the PSS and SSS to form a synchronization signal (SS) / PBCH block. The MIB provides the number of RBs in the system bandwidth, as well as the system frame number (SFN). The Physical Downlink Shared Channel (PDSCH) carries user data, broadcast system information not transmitted through the PBCH (such as System Information Blocks (SIBs), and paging messages.

[0057] As in Figure 2CAs explained in , some REs carry DM-RSs for channel estimation at the base station (indicated as R for one specific configuration, but other DM-RS configurations are possible). The UE may transmit DM-RSs for the physical uplink control channel (PUCCH) and DM-RSs for the physical uplink shared channel (PUSCH). The PUSCH DM-RS may be transmitted in the first or first two symbols of the PUSCH. The PUCCH DM-RS may be transmitted in different configurations depending on whether a short PUCCH or a long PUCCH is transmitted and on the specific PUCCH format used. The UE may transmit a sounding reference signal (SRS). The SRS may be transmitted in the last symbol of the subframe. The SRS may have a comb structure, and the UE may transmit the SRS on one of the comb teeth. The SRS may be used by the base station for channel quality estimation to enable frequency-dependent scheduling on the UL.

[0058] Figure 2D An example of various UL channels within a subframe of an illustration frame. The PUCCH may be located at a location as indicated in one configuration. The PUCCH carries uplink control information (UCI), such as scheduling requests, channel quality indicator (CQI), precoding matrix indicator (PMI), rank indicator (RI), and HARQ acknowledgement (ACK) / negative ACK (NACK) feedback. The PUSCH carries data and may additionally be used to carry a buffer status report (BSR), a power headroom report (PHR), and / or UCI.

[0059] Figure 33 is a block diagram of a base station 310 in communication with a UE 350 in an access network. In the DL, IP packets from the EPC 160 may be provided to a controller / processor 375. The controller / processor 375 implements layer 3 and layer 2 functionality. Layer 3 includes a radio resource control (RRC) layer, and layer 2 includes a service data adaptation protocol (SDAP) layer, a packet data convergence protocol (PDCP) layer, a radio link control (RLC) layer, and a media access control (MAC) layer. The controller / processor 375 provides RRC layer functionality associated with broadcasting of system information (e.g., MIB, SIB), RRC connection control (e.g., RRC connection paging, RRC connection establishment, RRC connection modification, and RRC connection release), inter-radio access technology (RAT) mobility, and measurement configuration of UE measurement reports; PDCP layer functionality associated with header compression / decompression, security (ciphering, cipher decryption, integrity protection, integrity verification), and handover support functions; RLC layer functionality associated with delivery of upper layer packet data units (PDUs), error correction through ARQ, concatenation, segmentation and reassembly of RLC service data units (SDUs), re-segmentation of RLC data PDUs, and reordering of RLC data PDUs; and MAC layer functionality associated with mapping between logical channels and transport channels, multiplexing of MAC SDUs onto transport blocks (TBs), demultiplexing of MAC SDUs from TBs, scheduling information reporting, error correction through HARQ, priority handling, and logical channel prioritization.

[0060] The transmit (TX) processor 316 and the receive (RX) processor 370 implement layer 1 functionality associated with various signal processing functions. Layer 1, including the physical (PHY) layer, may include error detection on the transport channel, forward error correction (FEC) encoding / decoding of the transport channel, interleaving, rate matching, mapping to the physical channel, modulation / demodulation of the physical channel, and MIMO antenna processing. The TX processor 316 handles the mapping to the signal constellation based on various modulation schemes (e.g., binary phase shift keying (BPSK), quadrature phase shift keying (QPSK), M-phase shift keying (M-PSK), M-quadrature amplitude modulation (M-QAM)). The coded and modulated symbols may then be split into parallel streams. Each stream may then be mapped to an OFDM subcarrier, multiplexed with a reference signal (e.g., pilot) in the time and / or frequency domain, and then combined together using an inverse fast Fourier transform (IFFT) to produce a physical channel carrying a time domain OFDM symbol stream. The OFDM stream is spatially precoded to produce multiple spatial streams. Channel estimates from a channel estimator 374 may be used to determine coding and modulation schemes and for spatial processing. The channel estimates may be derived from a reference signal and / or channel condition feedback transmitted by the UE 350. Each spatial stream may then be provided to a different antenna 320 via a separate transmitter 318TX. Each transmitter 318TX may modulate an RF carrier with a corresponding spatial stream for transmission.

[0061] At the UE 350, each receiver 354RX receives a signal through its corresponding antenna 352. Each receiver 354RX recovers the information modulated onto the RF carrier and provides the information to a receive (RX) processor 356. The TX processor 368 and the RX processor 356 implement layer 1 functionality associated with various signal processing functions. The RX processor 356 can perform spatial processing on the information to recover any spatial stream destined for the UE 350. If there are multiple spatial streams destined for the UE 350, they can be combined into a single OFDM symbol stream by the RX processor 356. The RX processor 356 then transforms the OFDM symbol stream from the time domain to the frequency domain using a fast Fourier transform (FFT). The frequency domain signal includes a separate OFDM symbol stream for each subcarrier of the OFDM signal. The symbols on each subcarrier, as well as the reference signal, are recovered and demodulated by determining the signal constellation point most likely transmitted by the base station 310. These soft decisions can be based on the channel estimates calculated by the channel estimator 358. These soft decisions are then decoded and deinterleaved to recover the data and control signals originally transmitted on the physical channel by the base station 310. These data and control signals are then provided to the controller / processor 359 which implements layer 3 and layer 2 functionality.

[0062] The controller / processor 359 may be associated with a memory 360 that stores program codes and data. The memory 360 may be referred to as a computer readable medium. In the UL, the controller / processor 359 provides demultiplexing between transport channels and logical channels, packet reassembly, cipher interpretation, header decompression, and control signal processing to recover IP packets from the EPC 160. The controller / processor 359 is also responsible for error detection using ACK and / or NACK protocols to support HARQ operations.

[0063] Similar to the functionality described in conjunction with DL transmissions performed by the base station 310, the controller / processor 359 provides RRC layer functionality associated with system information (e.g., MIB, SIB) acquisition, RRC connection, and measurement reporting; PDCP layer functionality associated with header compression / decompression, and security (encryption, decryption, integrity protection, integrity verification); RLC layer functionality associated with delivery of upper layer PDUs, error correction through ARQ, concatenation, segmentation, and reassembly of RLC SDUs, resegmentation of RLC data PDUs, and reordering of RLC data PDUs; and MAC layer functionality associated with mapping between logical channels and transport channels, multiplexing MAC SDUs onto TBs, demultiplexing MAC SDUs from TBs, scheduling information reporting, error correction through HARQ, priority handling, and logical channel prioritization.

[0064] Channel estimates derived by a channel estimator 358 from a reference signal or feedback transmitted by the base station 310 may be used by a TX processor 368 to select the appropriate coding and modulation schemes, and to facilitate spatial processing. The spatial streams generated by the TX processor 368 may be provided to different antennas 352 via separate transmitters 354TX. Each transmitter 354TX may modulate an RF carrier with a corresponding spatial stream for transmission.

[0065] UL transmissions are processed at the base station 310 in a manner similar to that described in conjunction with the receiver functionality at the UE 350. Each receiver 318RX receives a signal through its respective antenna 320. Each receiver 318RX recovers information modulated onto an RF carrier and provides the information to a RX processor 370.

[0066] The controller / processor 375 may be associated with a memory 376 that stores program codes and data. The memory 376 may be referred to as a computer readable medium. In the UL, the controller / processor 375 provides demultiplexing between transport channels and logical channels, packet reassembly, cipher decoding, header decompression, control signal processing to recover IP packets from the UE 350. The IP packets from the controller / processor 375 may be provided to the EPC 160. The controller / processor 375 is also responsible for error detection using ACK and / or NACK protocols to support HARQ operations.

[0067] In some aspects, at least one of the TX processor 368, the RX processor 356, and the controller / processor 359 may be configured to perform operations related to Figure 1 The RTT compensation UE component 199 combines various aspects.

[0068] In some other aspects, at least one of the TX processor 316, the RX processor 370, and the controller / processor 375 may be configured to perform operations related to Figure 1 The RTT compensation base station component 198 combines various aspects.

[0069] IoT allows devices such as UEs to receive, process, and analyze data from a network of other interconnected computing devices in various consumer and industrial applications (e.g., telecommunications, automotive, energy, health care, etc.). Especially in Industrial IoT (IIoT), where UEs may be located in refineries, power plants, hospitals, etc. and control their processes, time synchronization between devices is very important. For example, multiple IIoT UEs may communicate with a base station to monitor a patient's vital signs, etc. If the downlink / uplink subframe timing is not accurately synchronized at the base station and the UE, interference may occur and / or important data may be lost.

[0070] Therefore, in order to accurately synchronize the timing between the base station and the 5G-capable IIOT UE, the base station can send timing information (e.g., clock) to the UE based on IEEE1588v2 / Precision Time Protocol. However, according to this protocol, the base station can send timing information (e.g., clock) to the UE at a distance of less than 20 km. 2Within the service area of ​​the base station, the UE's operating clock domain must be synchronized to within ≤1μs with the global clock of the base station (e.g., synchronization master). Such service area parameters are typically present in outdoor macro network deployments, where the UE may be hundreds of meters away from the base station and the propagation delay of the transmission may be large (e.g., 3μs / km). Since such a large propagation delay can naturally offset the timing between the base station and the UE by more than 1μs, RTT compensation or propagation delay correction for timing synchronization between the base station and the UE may be required. Although timing synchronization based on the Global Positioning System (GPS) provides an alternative to IEEE1588v2 / Precision Time Protocol, 5G NR has an advantage because 5G NR provides a unified system for data communication and timing.

[0071] Therefore, there is a need for a solution that allows a base station to deliver timing information to a UE in an outdoor scenario while taking RTT compensation into account to meet the ≤1 μs synchronization accuracy parameter of the IEEE 1588v2 / Precision Time Protocol. There is also a need to provide a similar solution for certain UEs (e.g., IIOT UEs) while allowing other UEs (e.g., non-IIOT UEs and / or legacy UEs) to continue to observe lower precision timing synchronization parameters.

[0072] The present disclosure provides various methods and solutions for the above-mentioned needs in the following manner: allowing the base station to indicate the RTT compensation for the UE to use in adjusting the individual or local clock, thereby allowing the UE to synchronize with the clock of the base station relatively accurately. The present disclosure also provides that the UE is configured with different resolutions or granularities in the timing correction so that some UEs can achieve high-precision timing correction, while other UEs can adjust their clocks with lower accuracy. In this way, the base station can deliver timing information to the UE in an outdoor scenario while taking RTT compensation into account to meet the synchronization accuracy parameter of ≤1μs of the IEEE1588v2 / Precision Time Protocol. In addition, some UEs (e.g., IIOT UEs) can obtain higher accuracy for timing correction, while other UEs (e.g., non-IIOT UEs or legacy UEs) can observe lower-precision timing synchronization parameters.

[0073] Figure 44 is a diagram 400 illustrating an example communication flow of timing information 402 from one or more base stations 404 (e.g., base station 180) to a UE 406 (e.g., base station 102). The base station 404 may communicate with a 5G core network 408 (e.g., core network 190) via an N2 interface (e.g., via AMF 192) and / or an N3 interface (e.g., via UPF 195). The base station 404 may also communicate with the UE 406 via a wireless link or Uu interface, while the 5G core network 408 may communicate directly with the UE 406 via an N1 interface. The base stations 404 and the 5G core network may be components of a 5G core architecture 410.

[0074] A time sensitive network (TSN) system 412 may be connected to the 5G core network 408. The TSN 412 may include a master clock 414 used as a global clock for the base station 404. The TSN system 412 may be connected to the 5G core architecture 410 via a TSN link 416. The UE 406 includes a local clock 418 of the UE 406.

[0075] In order to synchronize the timing of the base station 404 and the UE 406, the base station first receives the timing information 402 from the master clock 414, and then provides the timing information 402 to the UE through the 5G air interface. In this way, the UE 406 can synchronize the local clock 418 or working clock with the global clock of the base station 404.

[0076] Figure 5 5 is a diagram 500 illustrating an example of transmission frames 502a, 502b respectively transmitted by a base station 504 and received by a UE 506. When the base station 504 sends a transmission frame 502a including timing information 507 (e.g., timing information 402 received from TSN 412), the UE 506 may receive a corresponding transmission frame 502b including the timing information after a propagation delay 508. In certain aspects, the UE 506 may compensate for the propagation delay 508 based on whether the timing information 507 is broadcast to the UE 506 or unicast to the UE 506.

[0077] In one aspect, the timing information 507 received from the TSN (e.g., TSN 412) may be broadcasted to multiple UEs 506 in common. In some aspects, the timing information 507 may include information associated with one or more symbols and / or one or more time slots 510 at the beginning of the frames 502a, 502b. For example, the timing information 507 may indicate a pointer to a frame number, which is used by the UE 506 to derive the frame number as the beginning of the downlink transmission. In some aspects, the beginning of the frame may refer to the first symbol of the frame, which may be the first symbol of the frame (e.g., the first OFDM symbol). Although the timing information 507 may be illustrated as appearing at the beginning of the frame, the timing information 507 may be carried in other locations (e.g., symbols) of the frame, which are not necessarily at the beginning of the frame. The base station 504 may broadcast the timing information 507 in the SIB with a resolution of 40 nanoseconds (ns). Each UE 506 receiving the broadcast message may then adjust its local clock (eg, Figure 4 The local clock 418 in ).

[0078] In some other aspects, the timing information 507 may be unicast to individual UEs 506 that require the timing information (e.g., for individual applications). The timing information 507 may indicate information associated with the start of the frames 502a, 502b. Unicast messages may typically be sent via the RRC protocol (e.g., in the RACH). When unicast signaling is used, since each UE has its own local clock (e.g., Figure 4 418 in the local clock 418), so potentially different timing information 507 with different compensations for propagation delay 508 can be sent individually to different UEs 506. In some aspects, the UE 506 can adjust its local clock based on an estimate of the propagation delay 508 known to the base station 504.

[0079] In one example, according to the first aspect of the present disclosure, Figure 4 and Figure 5, the base station 404, 504 or the network indicates timing information 402, 507 (e.g., common system timing) to the UE 406, 506 via unicast or broadcast signaling. The timing information 507 may indicate information associated with one or more symbols and / or time slots at the beginning of a downlink transmission (e.g., frame 502a). The UE 406, 506 receives a downlink transmission (e.g., frame 502b) from the base station 404, 504 after a propagation delay 508 from the transmitted frame 502a (e.g., based on the timing information 402, 507). The UE 406, 506 may then send an uplink transmission. Based on the RTT between the downlink and uplink transmissions, the base station 404, 504 may send an RTT compensation to the UE 406, 506. The timing information 402, 507 may be transmitted along with the RTT compensation. In one aspect, the RTT compensation may be a timing advance (TA) 512 within a timing advance (TA) command. For example, the base station 404, 504 may transmit the RTT compensation within a TA command in a random access response (RAR) of a RACH procedure, and the UE 406, 506 may receive the RTT compensation within a TA command in a random access response (RAR) of a RACH procedure.

[0080] After receiving the TA command with RTT compensation, the UE 406, 506 adjusts the local clock 418 using the timing advance 512 and delivers the adjusted time to the upper layers 514 (e.g., layer 2 and / or layer 3) of the UE 406, 506. For example, after receiving the broadcast timing information 402, 507, the UE 406, 506 may deliver the adjusted time to the upper layers 514 based on the following formula:

[0081] Time delivered to upper layer = broadcast time + "applied TA advance" / 2, where the broadcast time is the UE reception timing of the downlink transmission of the timing information 402, 507 after the propagation delay 508; and the "applied TA advance" is the timing advance 512 indicated in the TA command.

[0082] Therefore, in one aspect, the UE may generally use a timing advance framework to compensate and / or correct for the lack of timing synchronization caused by the propagation delay between the base station and the UE. Figure 6 , 7A 7B and the accompanying description describe certain aspects related to timing advance. On the other hand, the UE may use a separate procedure independent of the TA to correct the timing synchronization between the base station and the UE. Figure 8 and the accompanying description to describe certain aspects related to this other aspect.

[0083] In various aspects, the base station may indicate RTT compensation to the UE. The RTT compensation may include, for example, a TA within a TA command, a timing offset between a base station transmit timeline and a base station receive timeline, an estimated time difference between a base station transmit timing and a base station receive timing, and / or an actual time difference between a base station transmit timing and a base station receive timing and a UE transmit timing and a UE receive timing.

[0084] Figure 6 A diagram 600 illustrating various timelines for downlink and uplink transmissions between a base station 602 and a UE 604 is shown. Specifically, the base station 602 sends downlink transmissions according to a base station transmit timeline 606, and the base station receives uplink transmissions according to a base station receive timeline 608. Similarly, the UE 604 sends uplink transmissions according to a UE transmit timeline 610, and the UE receives downlink transmissions according to a UE receive timeline 612. In one aspect, to synchronize timing information corresponding to the UE and base station timelines (e.g., timing information 402, 507), the base station 602 may send RTT compensation (e.g., one or more TAs in one or more TA commands) to the UE 604. Based on the RTT compensation received from the base station 602, the UE 604 may control the timing of the UE transmit and receive timelines 610, 612 relative to the base station transmit and receive timelines 606, 608.

[0085] Generally, the base station transmit timeline 606 and the base station receive timeline 608 are aligned. However, in some aspects, the timelines 606, 608 may be offset. For example, Figure 6 A timing offset 614 or TA error (e.g., referred to as gNBRxOffset or some other name) between a base station transmit timeline 606 and a base station receive timeline 608 is illustrated. In situations where, for example, a UE 604 requires additional time to decode a downlink transmission and provide an ACK compared to the time that the base station 602 may require to decode the uplink transmission and provide an ACK, the base station 602 may (e.g., using a separate processor) adjust the base station receive timeline 608 to be offset from the base station transmit timeline 606. The base station 602 may also include the timing offset 614 in a frequency division duplex (FDD) system, where there may not be an inherent parameter for perfectly aligning the base station transmit timeline 606 and the base station receive timeline 608, and / or in a time division duplex (TDD) system, where the base station may flexibly align the timelines 606, 608 with any timing offset 614 because both timelines 606, 608 are within a guard period in the transmission channel bandwidth.

[0086] In certain aspects, when the base station 602 and the UE 604 communicate in TDD mode, the base station transmit timeline 606 and the base station receive timeline 608 are aligned within the protection period. In other aspects, uplink transmissions from multiple UEs 604 can be received by the base station 602 within the CP of subsequent downlink transmissions in TDD mode or FDD mode. In additional aspects, the timing advance command can request that the individual UE 604 advance or delay the UE transmit schedule 610 to synchronize with the timing of the base station 602.

[0087] In reference Figure 6 In one example, the base station 602 sends a downlink transmission including timing information and RTT compensation at time t1 in the transmission timeline 606. Time t1 can be synchronized with a master control clock (e.g., master control clock 414) and can be indicated in the timing information (e.g., timing information 402, 507). The RTT compensation can be equal to the timing advance 603 included in the TA command. After the downlink propagation delay 616, the UE 604 then receives the downlink transmission at time t2 in the reception timeline 612. Figure 6 As illustrated in relation to downlink transmissions, the UE reception timeline 612 is offset from the base station transmission timeline 606 by a downlink propagation delay 616 .

[0088] To compensate for the offset, UE 604 applies RTT compensation (e.g., received timing advance 603) to the local clock so that UE transmit timeline 610 is advanced relative to base station receive timeline 608. Figure 6 6, the UE transmit timeline 610 is advanced relative to the base station receive timeline 608. The UE 604 then transmits the uplink transmission at time t3 in the transmit timeline 610. After an uplink propagation delay 618, the base station 602 then receives the uplink transmission at time t4 in the receive timeline 608.

[0089] As a result, the local clock of UE 604 can be synchronized with the global clock of base station 602 using RTT compensation. Although base station receive timeline 608 can be aligned with base station transmit timeline 606, timelines 606, 608 can include timing offset 614 in some other aspects, such as Figure 6 Potentially, when base station receive timeline 608 is aligned with base station transmit timeline 606, downlink propagation delay 616 is typically the same as uplink propagation delay 618. As a result, the RTT compensation applied by UE 604 may typically be twice the propagation delay 616 or the propagation delay 618.

[0090] Fig. 7A and 7B Different examples of frame structures in which a base station can provide a TA command to a UE are illustrated. For example, Fig. 7A An example of a MAC control element (CE) (MAC-CE 700) including a 6-bit TA command 702 (eg, a maximum 6-bit TA command) and a timing advance group ID (TAG-ID) 704 is illustrated. In addition, Figure 7B An example of a RAR 750 including a 12-bit TA command 752 (eg, a maximum 12-bit TA command) is illustrated. Fig. 7A and 7B The number of bits (eg, maximum number of bits) for the timing advance command shown in FIG. 1 is illustrative, and other numbers of bits may be used in addition to 6 or 12 bits for the TA command.

[0091] A base station (e.g., base station 602) may deliver different RTT compensation values ​​to a UE (e.g., UE 604) based on a frame structure for TA. In one example, if the UE is in a connected mode and actively receives communications from a base station, the base station may transmit and the UE may receive a MAC-CE 700 indicating a 6-bit TA command 702. In another example, if the UE is initially connected to the base station (e.g., via a RACH) or wakes up from a power save mode, the base station may transmit and the UE may receive a RAR 750 indicating a 12-bit TA command. The index value of the TA command 702 of the MAC-CE 700 may be between -31 and +31, and the index value of the TA command 752 of the RAR 750 may be between -2048 and +2048.

[0092] The TA applied by the UE is based on the TA index value (e.g. Fig. 7A or 7B) and the TA granularity. The TA granularity indicates the TA index value to be multiplied by it to obtain the TA (e.g., Figure 6 The time (T s ). For example, assuming a 15kHz subcarrier spacing (SCS), the TA granularity can be 16*64T s , where T s =1 / (64*30.72)μs (about 0.52μs in total). Since the TA command 702 of the MAC-CE 700 has a maximum index value of +31, the TA delivered in the MAC-CE 700 may have a maximum value of 31*0.52μs or about 16μs, and a minimum absolute non-zero value of 1*0.52μs or about 0.52μs or 520ns. Therefore, in one example, referring to Figure 6, when UE 604 receives a downlink transmission including timing information and TA 603 at time t2, assuming a TA granularity associated with a 15kHz SCS and a TA index value of 2, UE 604 may advance the UE transmit timeline 610 relative to the global clock of base station 602 by approximately 1 μs or 1000 ns.

[0093] The TA granularity may be a function of the SCS used in the communication between the base station and the UE. Since 5G includes multiple SCSs, different TA granularities may be applied depending on the SCS to obtain the TA. Table 1 illustrates examples of various TA granularities for different SCSs in 5G:

[0094]

[0095]

[0096] Table 1

[0097] Therefore, refer again to the above Figure 6 For example, if the SCS is changed from 15kHz to 30kHz with a TA index value of 2, the UE 604 may advance the UE transmit timeline 610 by approximately 0.5μs relative to the global clock of the base station 602. In some other aspects, if the SCS is changed to 120kHz, the UE 604 may advance the UE transmit timeline 610 by approximately 0.125μs.

[0098] Therefore, the UE can use TA as RTT compensation for the propagation delay between the base station and the UE to adjust its local clock to synchronize with the global clock of the base station. However, some UEs (e.g., IIOT UEs) may require higher timing synchronization accuracy than that provided by the aforementioned TA granularity to meet the ≤1μs parameter of the IEEE1588v2 / Precision Time Protocol. In addition, other UEs (e.g., legacy UEs) may not need to receive timing information with high-precision synchronization parameters from the base station. Therefore, in one aspect of the present disclosure, a finer, UE-specific TA granularity can be provided to improve the synchronization accuracy of IIOT UEs, while maintaining the aforementioned granularity and TA procedures for legacy UEs.

[0099] In various aspects, a base station (e.g., base station 602) or a network may configure a TA granularity that varies from UE to UE. Thus, different TA granularities may be configured for different UEs. For example, an IIOT UE may be configured to have a TA granularity associated with an SCS that is finer (e.g., smaller) than the TA granularity of a legacy UE. In addition, the TA granularity that varies from UE to UE may be different from any TA granularity indicated in Table 1 above.

[0100] In various aspects, a UE (e.g., UE 604) may report the UE identity as an IIOT UE or a legacy UE to a base station (e.g., base station 602) or another network node (e.g., during SRS, RACH, or other uplink transmissions). Depending on the reported UE identity, the base station may configure or indicate a TA granularity that varies from UE to UE. For example, if the base station receives a message from the UE including an identification as a legacy UE, the base station may configure the UE with a TA granularity according to Table 1. In another example, if the base station receives a message from the UE including an identification as an IIOT UE, the base station may indicate to the UE a TA granularity that varies from UE to UE that is finer than those TA granularities indicated in Table 1 above. In other examples, the base station may indicate to the IIOT UE a TA granularity that is the same or larger than that of the legacy UE.

[0101] In one aspect, the TA granularity that varies from UE to UE may be configured separately from the TA command. For example, different TA granularities may be provided without changing the maximum size or header of the TA command 702, 752 in the MAC-CE 700 or the RAR 750. Conversely, the network may configure another set of TA granularities for the UE that are different from those in Table 1 to apply to the same TA command. For example, depending on the SCS used for communication between the base station and the UE, an IIOT UE may be configured with a different TA granularity (e.g., 64T) than a legacy UE. s or other granularities smaller than those in Table 1). In another example, legacy UEs may request the base station or network to configure these UEs with a TA granularity that may be different from other UEs per UE. In this way, the base station may send the same TA command to IIoT UEs and legacy UEs, while allowing UEs configured with different TA granularities to adjust their local clocks using different TAs (e.g., finer or smaller TAs - e.g., about 15 or 30 ns instead of 1 μs for IIoT UEs).

[0102] According to this aspect, a base station may determine that multiple TA commands are often sent to a UE configured with a TA granularity that varies from UE to UE. For example, a base station may send multiple TA commands to achieve a certain TA accuracy for an IIOT UE or other UE configured with a TA granularity that varies from UE to UE. For example, this may occur when an IIOT UE configured with a TA granularity smaller than those in Table 1 has moved away from the base station or experienced radio frequency interference, thereby increasing propagation delay and thus incurring multiple TA commands to compensate for the delay. However, this situation may result in a "slamming" effect, in which the base station may need to use multiple TA commands to "slam" the IIOT UE to achieve the same result (e.g., 1μs TA) that a single TA command could have achieved for a legacy UE. However, by fixing the maximum size or header of the TA command 702, 752 in the MAC-CE 700 or the RAR 750, this aspect limits the slamming effect based on the maximum index value that can be used for the TA command.

[0103] On the other hand, the base station may dynamically indicate a TA granularity that varies from UE to UE in a downlink transmission. The TA granularity that varies from UE to UE may be achieved by different TA commands used in conjunction with sending timing information to the UE. For example, the base station or the network may configure the MAC-CE 700 to have a new header or a larger TA command that is transmitted to the IIOT UE separately from other TA commands. The increase in size may allow the base station transmitting the MAC-CE to convey a higher resolution (e.g., higher accuracy) TA to certain UEs via a larger span of TA index values. In some other aspects, the size of the TA command may not increase, and the base station may transmit a MAC-CE with a different header value to convey a higher resolution TA to the UE via different TA granularities.

[0104] For example, one or more bits in the TA command 702 of the MAC-CE 700 may be used to specify the TA as being based on a first set of TA granularities (e.g., as shown in the example of Table 1) or based on a second set of finer TA granularities. In another example, one of the values ​​of the TAG ID 704 of the MAC-CE 700 may be used to specify the first or second set of TA granularities. In a further example, a new MAC-CE having a size or header value different from that of the MAC-CE 700 may be provided to a UE receiving a TA based on the second set of TA granularities. Thus, the above-described "slamming" effect may be limited by using separate TA commands for UEs having TA granularities that vary from UE to UE, because the base station does not need to repeatedly send a common TA command to these UEs.

[0105] On the other hand, referring to Figure 6, the TA 603 received and applied by the UE (e.g., IIOT UE) may be based on the timing offset 614 between the base station transmit timeline 606 and the base station receive timeline 608. Thus, with reference to Figure 4 and Figure 5 , after receiving a TA command with RTT compensation (e.g., TA 512), the UE 406, 506 may also use TA 512 to adjust the local clock 418 based on the timing offset 614. In this case, the UE 406, 506 may deliver the adjusted time to the upper layer 514 based on the following formula after receiving the broadcast timing information 402, 507:

[0106] Time delivered to upper layer = broadcast time + "TA advance applied" / 2 – gNBRxOffset, where:

[0107] The broadcast time is the UE reception timing of the downlink transmission, which indicates the timing information 402, 507 after the propagation delay 508;

[0108] The TA advance applied is the TA indicated in the TA command 512; and

[0109] gNBRxOffset (gNB receive offset) is the timing offset 614 between the base station transmit timeline 606 and the base station receive timeline 608.

[0110] In various aspects, the base station may indicate the timing offset 614 to the UE via a message separate from the timing information, rather than applying the timing offset 614 to the broadcasted timing information advertised by the base station. The separate message transmitted by the base station may be, for example, a physical layer (PLY) message, a layer 2 MAC message, or a layer 3 RRC message. Thus, when the base station transmits the timing information corresponding to the value t1 in the base station transmit timeline to the UE 604, the base station may allow the UE to calculate the correct timing information using the TA by indicating the timing offset 614. In this way, if legacy UEs or other UEs do not require high-precision time synchronization, they will not necessarily need to receive the broadcasted timing information with the RTT compensation applied.

[0111] Now refer to Figure 8 In a second aspect of the present disclosure, a base station or a network indicates timing information (eg, absolute time) including RTT compensation to a UE via a procedure separate and independent from a TA command. Figure 8 A diagram 800 is shown illustrating an example communication flow between a base station 802 and a UE 804 according to this second aspect of the disclosure. In one aspect, the RTT compensation is UE-specific and the timing information may be delivered to the UE via unicast signaling.

[0112] Base station 802 first sends a downlink transmission 806 at time t0, which may correspond to the start of a frame boundary from the perspective of the base station. Downlink transmission 806 may include an absolute time provided by a master control clock (e.g., Figure 5 804 then receives the downlink transmission 806 at time t1, which may correspond to the start of a frame boundary from the perspective of the UE. The UE then transmits an uplink transmission 808 at time t2. The uplink transmission 808 may be, for example, an SRS waveform (e.g., when the UE 804 is in connected mode) or a RACH waveform (e.g., when the UE 804 is in idle mode). The base station 802 then receives the uplink transmission 808 at time t3.

[0113] In one aspect, the base station 802 may explicitly communicate the RTT between the fixed time t0 and the time t3 at which the base station receives the uplink transmission, independent of the TA command. Figure 8 , value A represents the base station time difference 810 between t3 and t0, and value B represents the UE time difference 812 between t2 and t1. The UE can determine the RTT based on the values ​​of A and B, and thereby determine the propagation delay. In one aspect, the base station estimates the value A by calculating the difference between t3 and t0, and sends the value A to the UE in a message. For example, the base station can send the value A in a downlink transmission 806. Since the UE knows the value B, the UE can calculate the RTT by subtracting the value B from the value A received from the base station. The UE can then divide the RTT by 2 to obtain the one-way propagation delay, which the UE can use to adjust the timing information received from the base station to synchronize the local clock with the global clock.

[0114] In this way, the base station 802 or the network may indicate the value A as the RTT compensation for the UE 804 to use for timing synchronization in a message separate from the TA command. The message including the value A may be, for example, a PLY message, a layer 2 MAC message, or a layer 3 RRC message transmitted by the base station to the UE. Fig. 7A and Figure 7B ), messages including value A may not be so limited, and may therefore be, for example, in the range of tens of nanoseconds. Thus, value A has a higher granularity or precision for timing adjustments than TA commands, which, as described above, may be limited in size to a larger microsecond range. Furthermore, messages including value A may be sent less frequently than TA commands, thereby avoiding slamming effect problems.

[0115] Furthermore, once the UE obtains timing information with RTT compensation (e.g., value A), the UE may determine to adjust the timing information based on the propagation delay derived from the RTT compensation and value B as described above. Thus, this aspect of the disclosure allows for the use of a different framework than the TA to communicate the RTT compensation to the UE.

[0116] In another aspect, UE 804 may indicate value B to base station 802, and the base station may determine an RTT compensation for use by the UE in timing synchronization. For example, after the UE receives downlink transmission 806 at time t1, UE 804 may transmit value B to base station 802 in uplink transmission 808 at time t2. Once the base station receives value B, the base station may obtain RTT by calculating the actual value A and subtracting the value B indicated by the UE, and thereby obtain the propagation delay.

[0117] The base station 802 or the network may then provide RTT compensation (e.g., the difference between the values ​​of A and B) to the UE 804 based on whether the downlink transmission 806 including the timing information (e.g., the master clock time) is broadcast or unicast to the UE 804. In one aspect, if the downlink transmission 806 is broadcast to the UE 804, the base station 802 may provide the UE 804 with RTT compensation for the UE 804 to adjust the UE local clock to synchronize the timing information. For example, the RTT compensation may be broadcast to multiple UEs. On the other hand, if the downlink transmission 806 is unicast to the UE 804, the base station 802 may provide the UE 804 with RTT compensation (as discussed above), or use the RTT compensation to adjust the timing information and send the adjusted timing information to the UE 804.

[0118] Fig. 9 900 is a flow chart of a method of wireless communication. The method may be performed by a base station (e.g., a base station 102, 310, 404, 504, 602, 802; a device 1002 / 1002'; a processing system 1114, which may include a memory 376 and may be the entire base station 102, 310, 404, 504, 602, 802 or a component of the base station 102, 310, 404, 504, 602, 802 (such as a TX processor 316, an RX processor 370 and / or a controller / processor 375)). Optional aspects are illustrated with dashed lines. The method allows a base station to indicate an RTT compensation for a UE to use in adjusting its individual or local clock, thereby allowing the UE to synchronize with the base station's clock with high accuracy. The present disclosure also allows UEs to be configured with different resolutions or granularities in timing correction so that certain UEs can achieve high-precision timing correction while other UEs can adjust their clocks with lower accuracy.

[0119] At 902, the base station receives timing information from the TSN. For example, 902 may be Fig.10 For example, referring to Figure 4 In order to synchronize the timing of the base station 404 and the UE 406, the base station 404 receives the timing information 402 from the master control clock 414 and then provides the timing information 402 to the UE 406 (e.g., via the 5G air interface). The TSN 412 may include a master control clock 414, which serves as a global clock for the base station 404.

[0120] At 904, the base station sends a downlink transmission including timing information to the UE. For example, 904 may be performed by Fig.10 The timing information component 1006 and / or the transmission component 1008 are executed. The timing information may indicate information associated with the symbol and / or time slot at the beginning of the frame of the downlink transmission. Figure 4 and Figure 5 , the base station 404, 504 or the network indicates timing information 402, 507 (e.g., common system timing) to the UE 406, 506 via unicast or broadcast signaling. The timing information 402, 507 may indicate information associated with one or more symbols and / or time slots at the beginning of a downlink transmission (e.g., frame 502a). Figure 8 , the base station 802 may send a downlink transmission 806 to the UE 804 at time t0, which may correspond to the start of a frame boundary from the perspective of the base station 802. The downlink transmission 806 may include an absolute time provided by the master control clock (e.g., Figure 5 Timing information corresponding to the timing information 507 in.

[0121] In one aspect of 904, the downlink transmission including the timing information is broadcast to multiple UEs. In another aspect of 904, the downlink transmission including the timing information is unicast to the UEs. For example, referring to Figure 5 , the timing information 507 received from the TSN (e.g., TSN 412) may be commonly broadcast to multiple UEs including UE 506, and may include information associated with one or more symbols and / or one or more time slots 510 at the beginning of the frames 502a, 502b. For example, the base station 504 may broadcast the timing information 507 in the SIB with a resolution of 40ns. In some other aspects, the timing information 507 may be unicast to individual UEs 506 that need timing information (e.g., for individual applications), and may indicate information associated with the beginning of the frames 502a, 502b. When unicast signaling is used, since each UE has its respective local clock (e.g., Figure 4 418 in the local clock 418), so potentially different timing information 507 with different compensations for propagation delay 508 can be individually sent to different UEs including UE 506.

[0122] At 906, the base station receives an uplink transmission from the UE following the downlink transmission. For example, 906 may be performed by Fig.10 For example, referring to Figure 4 and Figure 5 , after the UE 406, 506 receives a downlink transmission (e.g., frame 502b) from the base station 404, 504 including the timing information 402, 507 later than the transmitted frame 502a by a propagation delay 508, the base station 404, 504 receives an uplink transmission from the UE 406, 506. Figure 8 , after UE 804 receives downlink transmission 806 at time t1, UE 804 transmits uplink transmission 808 at time t2. Uplink transmission 808 can be, for example, an SRS waveform (e.g., when UE 804 is in connected mode) or a RACH waveform (e.g., when UE 804 is in idle mode). Base station 802 then receives uplink transmission 808 at time t3.

[0123] At 908, the base station determines an RTT compensation associated with the timing information based on the RTT between the downlink transmission and the uplink transmission. For example, 908 may be performed by Fig.10 The RTT compensation determination component 1010 is executed. For example, referring to Figure 4 and Figure 5 Based on the RTT between downlink and uplink transmissions, the base station 404, 504 may send an RTT compensation associated with the timing information 402, 507 for the UE 406, 506, the RTT compensation being determined from one or more of: a TA within a TA command, a timing offset between base station transmit and receive timelines, an estimated time difference between base station transmit timing and base station receive timing, and an actual time difference between base station transmit and receive timing and UE transmit and receive timing. For example, the base station 404, 504 may transmit TA 512 within a TA command as the RTT compensation, and the UE may receive TA 512 within a TA command as the RTT compensation.

[0124] In one aspect of 908, the RTT compensation includes a TA associated with an adjustment of timing information transmitted to the UE. In one aspect, the TA is transmitted in a TA command, and the TA command is associated with a first TA granularity. For example, referring to Figure 5 and Figure 6 , the base station 504, 602 may determine the RTT compensation as the TA 512, 603 within the TA command. The base station 504, 602 may determine a TA index value (e.g., Fig. 7A MAC-CE 700 or Figure 7BThe TA command may be associated with a TA granularity that indicates the TA index value to be multiplied by to obtain the TA (e.g., Figure 6 The time (T s ). Examples of associated TA particle sizes are shown in Table 1 above.

[0125] At 910, the base station indicates to the UE a second TA granularity different from the first TA granularity based on the identity of the UE, wherein the identity of the UE indicates one of an IOT UE or a legacy UE. Potentially, the second TA may be referred to as "timing advance refinement" and / or "high precision timing advance". In some aspects, the second TA may be transmitted to the UE without transmitting the first TA. For example, the second TA may be used to indicate a finer granularity and / or a higher precision than the first TA, and thus, in some cases, the first TA may be omitted. For example, 910 may be performed by Fig.10 The second TA granularity may be finer than the first TA granularity. Figure 6 and Figure 7A-7B , the base station 602 may configure a UE-specific TA granularity (e.g., a second TA granularity) that is different from the aforementioned TA granularity (e.g., a first TA granularity) as shown in, for example, Table 1. Therefore, different TA granularities may be configured for different UEs based on the UE reporting identity of the UE (e.g., an IIOT UE or a legacy UE). For example, an IIOT UE may be configured to have a finer (e.g., smaller) TA granularity associated with the SCS that is different from the TA granularity of the legacy UE. The base station may indicate the UE-specific TA granularity in a downlink transmission by, for example, configuring the MAC-CE 700 to have a new header or a larger sized TA command that is transmitted to the IIOT UE separately from other TA commands, or by transmitting a MAC-CE with a different header value to convey a higher resolution TA to the UE via a different TA granularity without increasing the size of the TA command.

[0126] In one aspect of 910, the second TA granularity may be preconfigured or indicated in a message separate from the TA command. Fig. 7A and 7B , different TA granularities may be provided without changing the maximum size or header of the TA command 702, 752 in the MAC-CE 700 or the RAR 750. For example, depending on the SCS used for communication between the base station and the UE, an IIOT UE may be configured with a different TA granularity (e.g., 64T) than a legacy UE. sor other granularities smaller than those in Table 1). In another example, the legacy UEs may request the base station or network to configure these UEs with a TA granularity that may be different from other UEs. In some other aspects, a new MAC-CE having a size or header value different from MAC-CE 700 may be provided to the UE receiving the TA based on the second set of TA granularities.

[0127] In another aspect of 910, a second TA granularity is indicated within the TA command. In various examples, one or more bits in the TA command 702 of the MAC-CE 700 may be used to specify the TA as being based on a first set of TA granularities (e.g., as shown in the example of Table 1) or based on a second set of finer TA granularities. In another example, one of the values ​​of the TAG ID 704 of the MAC-CE 700 may be used to specify the first or second set of TA granularities.

[0128] In some aspects, the base station transmit timing of the downlink transmission and the base station receive timing of the uplink transmission are aligned within the protection period. In other aspects, the UE's uplink transmission is received within the cyclic prefix of the subsequent downlink transmission. For example, referring to Figure 6 , when the base station 602 and the UE 604 communicate in TDD mode, the base station transmit timeline 606 and the base station receive timeline 608 are aligned within the protection period. In other aspects, uplink transmissions from multiple UEs 604 can be received by the base station 602 within the CP of subsequent downlink transmissions in TDD mode or FDD mode.

[0129] In another aspect of 908, the RTT compensation may be indicated as TA based on a timing offset between the base station transmit timing and the base station receive timing. The timing offset is transmitted to the UE in a message separate from the timing information. For example, referring to Figure 6 , the base station may determine the RTT compensation as a timing offset 614 between the base station transmit and receive timelines 606, 608. In various aspects, the base station may indicate the timing offset 614 to the UE via a message separate from the timing information, rather than applying the timing offset 614 to the broadcasted timing information advertised by the base station.

[0130] In another aspect of 908, the RTT compensation may be an estimated time difference between the base station transmit timing of the downlink transmission and the base station receive timing of the uplink transmission. The estimated time difference may be transmitted to the UE in a message separate from the TA command. For example, referring to Figure 8, the base station may determine the RTT compensation as an estimated time difference (A) between the base station transmit timing (t0) of the downlink transmission 806 and the base station receive timing (t3) of the uplink transmission 808. The base station may estimate the value A by calculating the difference between t3 and t0, and may send the value A in the downlink transmission 806. The message including the value A may be, for example, a layer 2 MAC message or a layer 3 RRC message transmitted by the base station to the UE separately from the TA command.

[0131] In some aspects where the RTT compensation is separate from the TA command, the TA command can be associated with a first TA granularity, and the RTT compensation can indicate a second TA granularity that is different from the first TA granularity. Figure 8 , the base station 802 or the network may indicate the value A as the RTT compensation for the UE 804 to use for timing synchronization in a message separate from the TA command. The TA command 702 or 752 (see Table 1 above) may be limited in size to a small number of bits and associated with a TA granularity such as those in Table 1 above. Fig. 7A and Figure 7B ), a message including value A may not be so limited and may be associated with a finer TA granularity, thus, for example, in the range of tens of nanoseconds. Thus, value A has a higher granularity or precision for timing adjustments than a TA command, which, as described above, may be limited in size to a larger microsecond range.

[0132] In additional aspects of 908, the determined RTT compensation can be an actual time difference between the base station time difference and the UE time difference. To make this determination, at 912, the base station receives a UE time difference between a UE receive timing of a downlink transmission and a UE transmit timing of an uplink transmission, and at 914, the base station determines a base station time difference between a base station transmit timing of the downlink transmission and a base station receive timing of the uplink transmission. For example, 912 can be performed by receiving component 1004, and 914 can be performed by base station time difference determining component 1014. For example, referring to Figure 8 , after the UE receives the downlink transmission 806 sent at time t0 at time t1, the UE 804 may transmit the value B (UE time difference between t2 and t1) to the base station 802 in an uplink transmission 808 at time t2. Once the base station receives the value B at time t3, the base station may obtain the RTT and thus the propagation delay by calculating the actual value A (base station time difference between t3 and t0) and subtracting the value B (t2-t1) indicated by the UE. The base station may therefore determine the RTT compensation as the actual time difference (A-B) between the base station transmit timing (t0) and the base station receive timing (t3) and the UE transmit timing (t2) and the UE receive timing (t1).

[0133] At 916, the base station adjusts the timing information based on the RTT compensation. For example, 916 may be performed by Fig.10 The base station timing adjustment component 1016 is executed. For example, referring to Figure 8 , if the downlink transmission 806 is unicast to the UE 804, the base station 802 may adjust the timing information with the RTT compensation and send the adjusted timing information to the UE.

[0134] At 918, the base station transmits RTT compensation to the UE. For example, 918 may be performed by Fig.10 The RTT compensation allows the RTT to occur within a maximum of 1 microsecond of the downlink transmission. Figure 4-8 , the base station 404 may send the RTT compensation to the UE 406. The timing information 402, 507 may be transmitted together with the RTT compensation. In one aspect, the RTT compensation may be the TA 512 within the TA command. The RTT compensation may be sent, for example, at time t1 in the base station transmit timeline 606. In another aspect, referring to Figure 6 , the RTT compensation may be a timing offset 614, and the base station may indicate the timing offset 614 to the UE via a message separate from the timing information. The separate message may be a PLY message, a MAC message, or an RRC message. In a further aspect, referring to Figure 8 , the RTT compensation may be an estimated value A, and the base station 802 or the network may indicate the value A as the RTT compensation for the UE 804 to use for timing synchronization in a message separate from the TA command. The separate message may be a PLY message, a MAC message, or an RRC message. In additional aspects, reference is made to Figure 8 , the RTT compensation may be a value (A–B), and the base station 802 or the network may provide the RTT compensation (e.g., the difference between the values ​​of A and B) to the UE 804 based on whether the downlink transmission 806 including the timing information (e.g., the master clock time) is broadcast or unicast to the UE 804. In this way, the base station may deliver timing information to the UE in an outdoor scenario while taking the RTT compensation into account to meet the synchronization accuracy parameter of ≤1 μs of the IEEE 1588v2 / Precision Time Protocol.

[0135] In certain aspects of 918, when the downlink transmission is broadcast, the RTT compensation is transmitted to multiple UEs. In other aspects, when the downlink transmission is unicast, the timing information is adjusted based on the RTT compensation, and the adjusted timing information is transmitted to the UE. For example, referring to Figure 8, the base station 802 or the network may provide RTT compensation (e.g., the difference between the values ​​of A and B) to the UE 804 based on whether the downlink transmission 806 including the timing information (e.g., the master clock time) is broadcast or unicast to the UE 804. In one aspect, if the downlink transmission 806 is broadcast to the UE 804, the base station 802 may provide the UE with RTT compensation for the UE to adjust its local clock to synchronize the timing information. For example, the RTT compensation may be broadcast to multiple UEs. On the other hand, if the downlink transmission 806 is unicast to the UE 804, the base station 802 may provide the UE with RTT compensation as discussed above, or use the RTT compensation to adjust the timing information and send the adjusted timing information to the UE.

[0136] Fig.10 1 is a conceptual data flow diagram 1000 illustrating the data flow between different devices / components in an example apparatus 1002. The apparatus may be a base station (e.g., base station 102, 310, 404, 504, 602, 802) in communication with a UE 1015 (e.g., UE 104, 350, 406, 506, 604, 804) and a TSN (e.g., TSN system 412).

[0137] Device 1002 includes a receiving component 1004 that receives timing information from TSN, for example, as described in conjunction with Fig. 9 The receiving component 1004 also receives an uplink transmission from the UE 1050 after the downlink transmission, for example, as described in conjunction with Fig. 9 The receiving component 1004 also receives the UE time difference between the UE receive timing of the downlink transmission and the UE transmit timing of the uplink transmission, for example, as described in conjunction with Fig. 9 The receiving component 1004 also receives the identity reported by the UE, for example, as described in conjunction with Fig. 9 The 910 described.

[0138] Device 1002 includes a timing information component 1006 that receives timing information from TSN system 1060 (e.g., TSN 412) via receiving component 1004, for example, as described in conjunction with Fig. 9 The base station's global clock 1070 may be updated with the timing information. The timing information component 1006 also sends a downlink transmission including the timing information to the UE 1050 via the transmission component 1008, for example, in combination with a transmission from Fig. 9 904 described. Although Fig.10 The global clock 1070 is illustrated as part of the timing information component 1006, but they may be separate components.

[0139] The device 1002 includes an RTT compensation determining component 1010 that determines an RTT compensation associated with the timing information based on the RTT between the downlink transmission and the uplink transmission, for example, as combined with the timing information from Fig. 9 908. The RTT compensation determining component 1010 includes a granularity indicating component 1012, which indicates to the UE a second TA granularity different from the first TA granularity based on the identity of the UE received via the receiving component 1004, for example, in combination with the TA granularity from Fig. 9 910. The RTT compensation determining component 1010 also includes a base station time difference determining component 1014, which determines the base station time difference between the base station transmit timing of the downlink transmission and the base station receive timing of the uplink transmission, for example, as combined with the base station time difference from Fig. 9 914. The RTT compensation determining component 1010 also transmits the RTT compensation to the UE via the transmission component 1008, for example, as combined with Fig. 9 The 918 described.

[0140] Device 1002 additionally includes a base station timing adjustment component 1016 that adjusts timing information based on the RTT compensation received from RTT compensation determination component 1010 and the timing information received from timing information component 1006, for example, in combination with the timing information received from Fig. 9 The base station timing adjustment component 1016 sends the adjusted timing information to the UE 1050 via the transmission component 1008.

[0141] Transmitting component 1008 of device 1002 sends a downlink transmission to UE 1050 that includes timing information received from timing information component 1006 , RTT compensation received from RTT compensation determining component 1010 , and adjusted timing information received from base station timing adjusting component 1016 .

[0142] Device 1002 may include executing Fig. 9 The additional components of each box of the algorithm in the preceding flowchart. Thus, Fig. 9 Each block in the aforementioned flow chart of can be performed by a component and the device may include one or more of those components. These components can be one or more hardware components specially configured to perform the process / algorithm, implemented by a processor configured to perform the process / algorithm, stored in a computer-readable medium for implementation by a processor, or some combination thereof.

[0143] Fig.111 is a diagram 1100 illustrating an example of a hardware implementation of a device 1002' employing a processing system 1114. The processing system 1114 may be implemented with a bus architecture generally represented by a bus 1124. Depending on the specific application of the processing system 1114 and the overall design constraints, the bus 1124 may include any number of interconnecting buses and bridges. The bus 1124 links various circuits together, including one or more processors and / or hardware components (represented by the processor 1104, components 1004, 1006, 1008, 1010, 1012, 1014, 1016, and computer readable medium / memory 1106). The bus 1124 may also link various other circuits, such as timing sources, peripherals, voltage regulators, and power management circuits, which are well known in the art and therefore will not be described further.

[0144] The processing system 1114 may be coupled to the transceiver 1110. The transceiver 1110 is coupled to one or more antennas 1120. The transceiver 1110 provides a means for communicating with various other equipment via a transmission medium. The transceiver 1110 receives signals from the one or more antennas 1120, extracts information from the received signals, and provides the extracted information to the processing system 1114 (specifically, the receiving component 1004). In addition, the transceiver 1110 receives information from the processing system 1114 (specifically, the transmission component 1008) and generates signals to be applied to the one or more antennas 1220 based on the received information. The processing system 1114 includes a processor 1104 coupled to a computer-readable medium / memory 1106. The processor 1104 is responsible for general processing, including the execution of software stored on the computer-readable medium / memory 1106. The software, when executed by the processor 1104, causes the processing system 1114 to perform the various functions described above for any particular equipment. The computer-readable medium / memory 1106 may also be used to store data manipulated by the processor 1104 when executing software. The processing system 1114 further includes at least one of the components 1004, 1006, 1008, 1010, 1012, 1014, 1016. These components may be software components running in the processor 1104, software components resident / stored in the computer-readable medium / memory 1106, one or more hardware components coupled to the processor 1104, or some combination thereof. The processing system 1114 may be a component of the base station 310 and may include the memory 376 and / or at least one of the following: the TX processor 316, the RX processor 370, and the controller / processor 375. In some other aspects, the processing system 1114 may be the entire base station (e.g., see Figure 3 310).

[0145] In one configuration, an apparatus 1002 / 1002' for wireless communication includes: means for sending a downlink transmission including timing information to a UE; means for receiving an uplink transmission from the UE after the downlink transmission; means for determining an RTT compensation associated with the timing information based on the RTT between the downlink transmission and the uplink transmission; and means for transmitting the RTT compensation to the UE. The apparatus 1002 / 1002' may further include: means for receiving the timing information from the TSN; means for adjusting the timing information based on the RTT compensation; and means for indicating a second TA granularity different from the first TA granularity to the UE based on the identity of the UE, wherein the identity of the UE indicates one of an IIOT UE or a legacy UE. The apparatus 1002 / 1002' may additionally include: means for receiving a UE time difference between a UE receive timing of the downlink transmission and a UE transmit timing of the uplink transmission; and means for determining a base station time difference between a base station transmit timing of the downlink transmission and a base station receive timing of the uplink transmission.

[0146] The aforementioned means may be one or more of the aforementioned components of the device 1002 and / or the processing system 1114 of the device 1002' configured to perform the functions recited by the aforementioned means. As described above, the processing system 1114 may include the TX processor 316, the RX processor 370, and the controller / processor 375. Thus, in one configuration, the aforementioned means may be the TX processor 316, the RX processor 370, and the controller / processor 375 configured to perform the functions recited by the aforementioned means.

[0147] Fig.12 1200 is a flow chart of a wireless communication method. The method may be performed by a UE (e.g., UE 104, 350, 406, 506, 604, 804; device 1302 / 1302'; processing system 1414, which may include memory 360 and may be the entire UE 104, 350, 406, 506, 604, 804 or a component of the UE 104, 350, 406, 506, 604, 804 (such as TX processor 368, RX processor 356, and / or controller processor 359)). Optional aspects are illustrated with dashed lines. The method allows the UE to obtain RTT compensation from the base station for use in adjusting its individual or local clock, thereby allowing the UE to synchronize with the base station's clock with high accuracy. The present disclosure also allows the UE to be configured with different resolutions or granularities in timing correction so that some UEs can achieve high-precision timing correction while other UEs can adjust their clocks with lower accuracy.

[0148] At 1202, the UE receives a downlink transmission including timing information from a base station. For example, 1202 may be performed by Fig.13The timing information may indicate information associated with the start of a frame of a downlink transmission. Figure 4 and Figure 5 , the UE 406, 506 receives a downlink transmission (e.g., frame 502b) from the base station including timing information 402, 507 after a propagation delay 508 from the transmitted frame 502a. The timing information 402, 507 may be associated with one or more symbols and / or time slots at the beginning of the downlink transmission (e.g., frame 502a and / or frame 502b). Figure 8 , UE 804 may receive downlink transmission 806 at time t1, which may correspond to the start of a frame boundary from the perspective of the UE. Downlink transmission 806 may include an absolute time provided by a master control clock (e.g., Figure 5 Timing information corresponding to the timing information 507 in.

[0149] In one aspect of 1202, a downlink transmission including timing information is received via a broadcast. In another aspect of 1202, a downlink transmission including timing information is received via a unicast. For example, referring to Figure 5 , the timing information 507 received from the TSN (e.g., TSN 412) can be commonly broadcast to multiple UEs, and the timing information 507 can refer to one or more symbols and / or one or more time slots 510 at the beginning of the frame 502a, 502b. In some other aspects, the timing information 507 can be unicast to individual UEs 506 that should receive the timing information (e.g., for individual applications), and / or can refer to the beginning of the frame 502a, 502b. When unicast signaling is used, since each UE has its own local clock (e.g., Figure 4 418 in the local clock 418), so that potentially different timing information 507 with different compensations for the propagation delay 508 can be received separately by different UEs 506.

[0150] At 1204, the UE sends an uplink transmission to the base station after the downlink transmission. For example, 1204 may be performed by Fig.13 For example, referring to Figure 4 and Figure 5 , the UE 406, 506 receives a downlink transmission (eg, frame 502b) including timing information 402, 507 from the base station, and the UE may subsequently send an uplink transmission.

[0151] In some aspects, the base station transmit timing of the downlink transmission and the base station receive timing of the uplink transmission are aligned within the protection period. In other aspects, the uplink transmission is transmitted to the base station within the cyclic prefix of the subsequent downlink transmission. For example, referring to Figure 6, when the base station 602 and the UE 604 communicate in TDD mode, the base station transmit timeline 606 and the base station receive timeline 608 are aligned within the protection period. In other aspects, uplink transmissions from multiple UEs 604 can be received by the base station 602 within the CP of subsequent downlink transmissions in TDD mode or FDD mode.

[0152] At 1206, the UE obtains RTT compensation for the timing information based on the RTT between the downlink transmission and the uplink transmission. For example, 1206 can be performed by RTT compensation component 1306. RTT compensation allows the RTT to occur within a maximum of 1 microsecond of the downlink transmission. For example, referring to Figure 4 and Figure 5 , based on the RTT between downlink and uplink transmissions, the UE 406 may obtain RTT compensation for the UE 406 associated with the timing information 402, 507 from the base station 404. The RTT compensation may be one or more of: a TA within a TA command, a timing offset between base station transmit and receive timelines, an estimated time difference between base station transmit timing and base station receive timing, and an actual time difference between base station transmit and receive timing and UE transmit and receive timing. For example, the base station may transmit the TA 512 within the TA command as the RTT compensation, and the UE may receive the TA 512 within the TA command as the RTT compensation. In this way, the base station may deliver timing information to the UE in an outdoor scenario while taking the RTT compensation into account to meet the synchronization accuracy parameter of ≤1μs of the IEEE1588v2 / Precision Time Protocol.

[0153] In one aspect of 1206, the RTT compensation may be a TA used to adjust the timing information received by the UE. In one aspect, the TA is received in a TA command, and the TA command is associated with a first TA granularity. For example, referring to Figure 5 , 6 , 7A and 7B, the UE may receive RTT compensation in a TA command (e.g., TA 512). The TA is based on a TA index value (e.g., Fig. 7A or 7B) and the TA granularity, which indicates the TA index value multiplied by it to obtain the TA time (T s ). An example of the associated TA granularity is shown in Table 1 above. For example, when UE 604 receives a downlink transmission including timing information and TA 603 at time t2, assuming a TA granularity associated with a 15kHz SCS and a TA index value of 2, UE 604 may advance its UE transmit timeline 610 relative to the global clock of base station 602 by approximately 1 μs or 1000ns.

[0154] At 1207, the UE reports the identity of the UE to the base station, wherein the identity of the UE indicates one of an IOT UE or a legacy UE. For example, 1207 may be performed by Fig.13 The identity reporting component 1318 executes. For example, referring to Figure 6 and 7A -7B, a UE (e.g., UE 604) may report its identity as an IIOT UE or a legacy UE to a base station (e.g., base station 602) or another network node (e.g., during SRS, RACH, or other uplink transmissions). Depending on the reported UE identity, the base station may configure or indicate a TA granularity that varies from UE to UE. For example, if the UE transmits a message including an identification as a legacy UE to the base station, the base station may configure the UE with a TA granularity according to Table 1. In another example, if the UE transmits a message including an identification as an IIOT UE to the base station, the base station may indicate to the UE a TA granularity that varies from UE to UE that is finer than those TA granularities indicated in Table 1 above. In other examples, the base station may indicate to the IIOT UE a TA granularity that is the same or larger than that of the legacy UE.

[0155] At 1208, the UE receives a second TA granularity different from the first TA granularity based on the identity of the UE, where the identity of the UE indicates one of an IOT UE or a legacy UE. Potentially, the second TA may be referred to as "timing advance refinement" and / or "high precision timing advance". In some aspects, the second TA may be received without receiving the first TA. For example, the second TA may be used to indicate a finer granularity and / or a higher precision than the first TA, and thus, in some cases, the first TA may be omitted. For example, 1208 may be composed of Fig.13 The second TA granularity is finer than the first TA granularity. Figure 6 and Figure 7A-7B , the UE 604 may be configured with a UE-specific TA granularity (e.g., a second TA granularity) that is different from the aforementioned TA granularity (e.g., a first TA granularity) as shown in, for example, Table 1. Thus, different TA granularities may be configured for different UEs based on the identity (e.g., IIOT UE or legacy UE) reported by the UE at 1207. For example, an IIOT UE may be configured with a TA granularity associated with the SCS that is finer (e.g., smaller) than the TA granularity of the legacy UE. The UE may receive the UE-specific TA granularity in a downlink transmission, for example, by the MAC-CE 700 being reconfigured to have a new header or a larger sized TA command that is received by the IIOT UE separately from other TA commands, or by receiving a MAC-CE with a different header value that conveys a higher resolution TA via a different TA granularity without increasing the size of the TA command.

[0156] In one aspect of 1208, the second TA granularity may be preconfigured or received in a message separate from the TA command. Fig. 7A and 7B , different TA granularities may be configured or received without changing the maximum size or header of the TA command 702, 752 in the MAC-CE 700 or the RAR 750. For example, depending on the SCS used for communication between the base station and the UE, an IIOT UE may be configured with a different TA granularity (e.g., 64T) than a legacy UE. s or other granularities smaller than those in Table 1). In another example, legacy UEs may request the base station or network to configure these UEs with a TA granularity that may be different from other UEs. In some other aspects, a new MAC-CE having a size or header value different from MAC-CE 700 may be received by a UE configured to receive a TA based on a second set of TA granularities.

[0157] In another aspect of 1208, a second TA granularity is received within the TA command. In various examples, one or more bits in the TA command 702 of the MAC-CE 700 can be used to specify the TA as being based on a first set of TA granularities (e.g., as shown in Table 1) or based on a second set of finer TA granularities. In another example, one of the values ​​of the TAG ID 704 of the MAC-CE 700 can be used to specify the first or second set of TA granularities.

[0158] In another aspect of 1206, the RTT compensation may be a TA based on a time offset between a base station transmit timing for a downlink transmission and a base station receive timing for an uplink transmission. The timing offset is received in a message separate from the timing information. For example, referring to Figure 6 , the TA 603 received and applied by the UE may be based on a timing offset 614 (e.g., gNBRxOffset) between the base station transmit timeline 606 and the base station receive timeline 608. In various aspects, the UE may receive the timing offset 614 from the base station via a message separate from the timing information, rather than receiving the timing offset 614 that has been applied to the broadcasted timing information advertised by the base station. The separate message may be a PLY message, a MAC message, or an RRC message received from the base station.

[0159] In another aspect of 1206, the RTT compensation may be an estimated time difference between the base station transmit timing of the downlink transmission and the base station receive timing of the uplink transmission. The estimated time difference may be received in a message separate from the TA command. For example, referring to Figure 8, value A represents the base station time difference 810 between t3 (base station receive timing of uplink transmission 808) and t0 (base station transmit timing of downlink transmission 806). In one aspect, base station 802 estimates value A by calculating the difference between t3 and t0, and UE 804 receives value A from the base station in a message. The message including value A can be, for example, a PLY message, a layer 2 MAC message, or a layer 3 RRC message transmitted by the base station to the UE separately from the TA command.

[0160] In some aspects where the RTT compensation is separate from the TA command, the TA command is associated with a first TA granularity, and the RTT compensation indicates a second TA granularity that is different from the first TA granularity. Figure 8 , the UE 804 may receive a value A from the base station 802 or the network in a message separate from the TA command as an RTT compensation for the UE 804 to use for timing synchronization. The TA command 702 or 752 (see Table 1 above) may be limited in size to a small number of bits and associated with a TA granularity such as those in Table 1 above. Fig. 7A and Figure 7B ), a message including value A may not be so limited and may be associated with a finer TA granularity, thus, for example, in the range of tens of nanoseconds. Thus, value A has a higher granularity or precision for timing adjustments than a TA command, which, as described above, may be limited in size to a larger microsecond range.

[0161] In additional aspects of 906, the RTT compensation may be an actual time difference between a base station time difference and a UE time difference, wherein the base station time difference is a difference between a base station transmit timing of a downlink transmission and a base station receive timing of an uplink transmission, and wherein the UE time difference is a difference between a UE transmit timing of an uplink transmission and a UE receive timing of a downlink transmission. To obtain the actual time difference, at 1210, the UE determines a UE time difference between a UE receive timing of a downlink transmission and a UE transmit timing of an uplink transmission, and at 1212, the UE indicates the UE time difference to the base station. For example, 1210 may be determined by Fig.13 UE time difference determination component 1310 is executed, and 1212 can be performed by Fig.13 For example, referring to Figure 8, after UE 804 receives downlink transmission 806 sent at time t0 at time t1, and before transmitting uplink transmission 808 to base station 802 at time t2, UE determines value B (UE time difference between t2 and t1). UE 804 may then indicate value B to base station 802 in uplink transmission 808 at time t2. Once the base station receives value B at time t3, the base station may obtain RTT by calculating actual value A (base station time difference between t3 and t0) and subtracting value B (t2–t1) indicated by UE, and thereby obtain propagation delay. The actual time difference (A–B) between base station transmit timing (t0) and base station receive timing (t3) and UE transmit timing (t2) and UE receive timing (t1) may thus be determined.

[0162] In certain aspects of 1206, when the downlink transmission is broadcast, the RTT compensation is received via the broadcast. In other aspects, when the downlink is unicast, the adjusted timing information based on the RTT compensation is received from the base station. For example, referring to Figure 8 , UE 802 may receive RTT compensation (e.g., the difference between the values ​​of A and B) from base station 802 or the network based on whether downlink transmission 806 including timing information (e.g., master clock time) is broadcast or unicast to UE 804. In one aspect, if downlink transmission 806 is broadcast to UE 804, UE 804 may receive RTT compensation from base station 802 for UE to adjust its local clock to synchronize timing information. On the other hand, if downlink transmission 806 is unicast to UE 804, UE may receive RTT compensation from base station 802 as discussed above, or UE may receive timing information that has been adjusted using RTT compensation from the base station.

[0163] At 1214, the UE adjusts timing information based on the RTT compensation, wherein the timing information is delivered to an upper layer of the UE. The timing information delivered to the upper layer is based on the UE reception timing of the downlink transmission and the RTT compensation. For example, 1214 may be Fig.13 UE timing adjustment component 1316 performs. For example, referring to Figure 4 , 5 6, after receiving the TA command with RTT compensation (e.g., TA 512), the UE 406, 506 can use the TA 512 to adjust its local clock 418 and deliver the adjusted time to the upper layer 514 (e.g., layer 2 / layer 3) of the UE 406, 506. The delivered time can also be based on the timing offset 614. For example, the UE can deliver the adjusted time to the upper layer 514 based on the following formula after receiving the broadcast timing information 402, 507:

[0164] Time delivered to upper layer = broadcast time + "applied TA advance" / 2–gNBRxOffset, where: broadcast time is the UE reception timing of the downlink transmission of timing information 402, 507 after indicating the propagation delay 508; the applied TA advance is the TA 512 indicated in the TA command; and gNBRxOffset is the timing offset 614 between the base station transmission timeline 606 and the base station reception timeline 608.

[0165] At 1216, the UE adjusts the timing information based on the RTT compensation and the time difference between the UE reception timing of the downlink transmission and the UE transmission timing of the uplink transmission. For example, 1216 may be performed by Fig.13 UE timing adjustment component 1316 performs. For example, referring to Figure 8 Once the UE 804 obtains the timing information with the RTT compensation (e.g., value A), the UE 804 may determine to adjust the timing information based on the propagation delay derived from the RTT compensation and the value B (UE time difference 812 between the UE transmit timing t2 and the UE receive timing t1). For example, the UE may calculate the RTT by subtracting the value B from the value A received from the base station. The UE may then divide the RTT by 2 to obtain the one-way propagation delay, which the UE may use to adjust the timing information received from the base station to synchronize its local clock with the global clock.

[0166] Fig.13 is a conceptual data flow diagram 1302 illustrating the data flow between different means / components in an example apparatus 1300. The apparatus may be a UE (e.g., UE 104, 350, 406, 506, 604, 804) in communication with a base station (e.g., base station 102, 310, 404, 504, 602, 802).

[0167] Device 1302 includes a receiving component 1304 that receives a downlink transmission from a base station including timing information, e.g., as combined with a Fig.12 The timing information updates the local clock 1360 of the device 1302 as described in 1202.

[0168] The device 1302 includes an RTT compensation component 1306 that obtains RTT compensation for timing information based on the RTT between the downlink transmission and the uplink transmission, for example, as combined with Fig.12 The RTT compensation component 1306 includes a granularity receiving component 1308, which receives a second TA granularity different from the first TA granularity via the receiving component 1304 based on the identity of the UE, for example, as combined with Fig.12 As described in 1208.

[0169] The device 1302 also includes a UE time difference determining component 1310 that determines a UE time difference between a UE reception timing of a downlink transmission and a UE transmission timing of an uplink transmission, for example, as combined with Fig.12 The device also includes an indication component 1312, which indicates the UE time difference to the base station via a transmission component 1314 of the device 1302, for example, as combined with Fig.12 As described in 1212.

[0170] Device 1302 additionally includes a UE timing adjustment component 1316 that adjusts timing information based on the RTT compensation, the timing information being delivered to upper layers of the UE, e.g., as described in conjunction with Fig.12 1214 in. The UE timing adjustment component 1316 also adjusts the timing information based on the RTT compensation and the time difference between the UE reception timing of the downlink transmission and the UE transmission timing of the uplink transmission, for example, as combined with the timing information from Fig.12 1216 described.

[0171] After receiving the downlink transmission via the receiving component 1304, the transmitting component 1314 sends an uplink transmission to the base station 1350. The transmitting component 1314 also sends the UE time difference received from the indicating component 1312. The transmitting component 1314 further sends the UE identity (e.g., IOT UE or legacy UE) received from the identity reporting component 1318 of the device 1302 to the base station 1350.

[0172] The apparatus may include executing Fig.12 The additional components of each box of the algorithm in the preceding flowchart. Thus, Fig.12 Each block in the aforementioned flow chart of can be performed by a component and the device may include one or more of those components. These components can be one or more hardware components specially configured to perform the process / algorithm, implemented by a processor configured to perform the process / algorithm, stored in a computer-readable medium for implementation by a processor, or some combination thereof.

[0173] Fig.141400 is a diagram illustrating an example of a hardware implementation of a device 1302' employing a processing system 1414. The processing system 1414 may be implemented with a bus architecture generally represented by a bus 1424. Depending on the specific application of the processing system 1414 and the overall design constraints, the bus 1424 may include any number of interconnecting buses and bridges. The bus 1424 links together various circuits, including one or more processors and / or hardware components (represented by the processor 1404, components 1304, 1306, 1308, 1310, 1312, 1314, 1316, 1318, and computer readable medium / memory 1406). The bus 1424 may also link various other circuits, such as timing sources, peripherals, voltage regulators, and power management circuits, which are well known in the art and therefore will not be described further.

[0174] The processing system 1414 may be coupled to the transceiver 1410. The transceiver 1410 is coupled to one or more antennas 1420. The transceiver 1410 provides a means for communicating with various other equipment via a transmission medium. The transceiver 1410 receives signals from the one or more antennas 1420, extracts information from the received signals, and provides the extracted information to the processing system 1414 (specifically, the receiving component 1304). In addition, the transceiver 1410 receives information from the processing system 1414 (specifically, the transmission component 1314) and generates signals to be applied to the one or more antennas 1420 based on the received information. The processing system 1414 includes a processor 1404 coupled to a computer-readable medium / memory 1406. The processor 1404 is responsible for general processing, including the execution of software stored on the computer-readable medium / memory 1406. The software, when executed by the processor 1404, causes the processing system 1414 to perform the various functions described above for any particular equipment. The computer-readable medium / memory 1406 may also be used to store data manipulated by the processor 1404 when executing software. The processing system 1414 further includes at least one of the components 1304, 1306, 1308, 1310, 1312, 1314, 1316, 1318. These components may be software components running in the processor 1404, software components resident / stored in the computer-readable medium / memory 1406, one or more hardware components coupled to the processor 1404, or some combination thereof. The processing system 1414 may be a component of the UE 350 and may include the memory 360 and / or at least one of the following: the TX processor 368, the RX processor 356, and the controller / processor 359. In some other aspects, the processing system 1414 may be the entire UE (e.g., see Figure 3 of 350).

[0175] In one configuration, a device 1302 / 1302' for wireless communication includes: a device for receiving a downlink transmission including timing information from a base station; a device for sending an uplink transmission to the base station after the downlink transmission; and a device for obtaining RTT compensation for the timing information based on the RTT between the downlink transmission and the uplink transmission. The device 1302 / 1302' may also include: a device for adjusting the timing information based on the RTT compensation, wherein the timing information is delivered to the upper layer of the device 1302 / 1302'; and a device for adjusting the timing information based on the RTT compensation and the time difference between the UE reception timing of the downlink transmission and the UE transmission timing of the uplink transmission. The device 1302 / 1302' may further include a device for receiving a second TA granularity different from the first timing advance granularity based on the identity of the device 1302 / 1302', wherein the identity of the device 1302 / 1302' indicates one of an IOT UE or a legacy UE. Device 1302 / 1302' may additionally include: a device for determining a UE time difference between a UE receive timing of a downlink transmission and a UE transmit timing of an uplink transmission; and a device for indicating the UE time difference to a base station, wherein the RTT compensation indicates an actual time difference between the base station time difference and the UE time difference, and the base station time difference is the difference between the base station transmit timing of the downlink transmission and the base station receive timing of the uplink transmission.

[0176] The aforementioned means may be one or more of the aforementioned components of the device 1302 and / or the processing system 1414 of the device 1302' configured to perform the functions recited by the aforementioned means. As described above, the processing system 1414 may include the TX processor 368, the RX processor 356, and the controller / processor 359. Thus, in one configuration, the aforementioned means may be the TX processor 368, the RX processor 356, and the controller / processor 359 configured to perform the functions recited by the aforementioned means.

[0177] The present disclosure thus allows a base station to indicate RTT compensation for use by a UE in adjusting its individual or local clock, thereby allowing the UE to synchronize with the base station's clock with high accuracy. The present disclosure also allows UEs to be configured with different resolutions or granularities in timing correction so that certain UEs can achieve high-precision timing correction, while other UEs can adjust their clocks with lower accuracy. In this way, a base station can deliver timing information to a UE in an outdoor scenario while taking RTT compensation into account to meet the IEEE1588v2 / Precision Time Protocol's synchronization accuracy parameter of ≤1μs. In addition, certain UEs (e.g., IIOT UEs) can obtain higher accuracy for timing correction, while other UEs (e.g., non-IIOT UEs and / or legacy UEs) can observe other, lower-precision timing synchronization parameters.

[0178] It should be understood that the specific order or hierarchy of each box in the disclosed process / flowchart is an illustration of an example approach. It should be understood that the specific order or hierarchy of each box in these process / flowcharts can be rearranged based on design preferences. In addition, some boxes can be combined or omitted. The attached method claims present the elements of various boxes in an exemplary order and are not meant to be limited to the specific order or hierarchy presented.

[0179] The previous 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 easily understood by those skilled in the art, and the universal principles defined in this article can be applied to other aspects. Thus, the claims are not intended to be limited to the aspects shown in this article, but should be granted the full scope consistent with the claims in language, wherein the singular reference of the elements is not intended to represent "there is and only one", but "one or more", unless otherwise stated. The wording "exemplary" is used in this article to mean "used as an example, instance, or explanation". Any aspect described as "exemplary" herein does not have to be interpreted as being superior to or superior to other aspects. Unless otherwise stated, the term "some / certain" refers to one or more. Combinations such as "at least one of A, B or C", "one or more of A, B or C", "at least one of A, B and C", "one or more of A, B and C" and "A, B, C or any combination thereof" include any combination of A, B and / or C, and may include multiple A, multiple B or multiple C. Specifically, combinations such as "at least one of A, B, or C," "one or more of A, B, or C," "at least one of A, B, and C," "one or more of A, B, and C," and "A, B, C, or any combination thereof" may be A only, B only, C only, A and B, A and C, B and C, or A and B and C, wherein any such combination may include one or more members of A, B, or C. All structural and functional equivalents of the elements of the various aspects described throughout this disclosure that are currently or hereafter known to those of ordinary skill in the art 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, regardless of whether such disclosure is expressly recorded in the claims. The terms "module," "mechanism," "element," "device," and the like may not be a substitute for the term "means." Thus, no claim element should be interpreted as a means-plus-function unless the element is explicitly stated using the phrase "means for..."

Claims

1. A method for wireless communication by a base station, comprising: sending a downlink transmission including the timing information to a user equipment UE via unicast; receiving an uplink transmission from the UE subsequent to the downlink transmission; determining an RTT compensation associated with the timing information based on a round trip time (RTT) between the downlink transmission and the uplink transmission; as well as The RTT compensation is transmitted to the UE.

2. The method of claim 1, wherein: The downlink transmission including the timing information sent via unicast comprises a Radio Resource Control, RRC, message.

3. The method of claim 1, further comprising: The timing information is received from a time sensitive network TSN.

4. The method of claim 1, wherein: The timing information indicates information associated with a start of a frame of the downlink transmission.

5. The method of claim 1, further comprising: The timing information is adjusted based on the RTT compensation.

6. The method of claim 1, wherein: The RTT compensation includes a timing advance associated with an adjustment of the timing information transmitted to the UE.

7. The method of claim 6, wherein: The base station transmit timing of the downlink transmission and the base station receive timing of the uplink transmission are aligned within a protection period.

8. The method of claim 6, wherein: The uplink transmission of the UE is received within a cyclic prefix of a subsequent downlink transmission.

9. The method of claim 6, wherein: The timing advance is transmitted in a timing advance command, and the timing advance command is associated with a first timing advance granularity.

10. The method of claim 9, further comprising: A second timing advance granularity different from the first timing advance granularity is indicated to the UE based on an identity of the UE, wherein the identity of the UE comprises one of an Industrial Internet of Things IIOT UE or a legacy UE.

11. A method for wireless communication at a user equipment UE, comprising: receiving a downlink transmission including timing information from a base station via unicast; sending an uplink transmission to the base station subsequent to the downlink transmission; as well as An RTT compensation for the timing information is determined based on a round trip time (RTT) between the downlink transmission and the uplink transmission.

12. The method of claim 11, wherein: The downlink transmission including the timing information received via unicast includes a Radio Resource Control, RRC, message.

13. The method of claim 11, wherein: The timing information indicates information associated with a start of a frame of the downlink transmission.

14. The method of claim 11, wherein: The RTT compensation includes a timing advance for adjusting the timing information received from the base station.

15. The method of claim 14, further comprising: The timing information is adjusted based on the RTT compensation, and the adjusted timing information is delivered to an upper layer of the UE.

16. The method of claim 14, wherein: The timing advance is received in a timing advance command, the timing advance command being associated with a first timing advance granularity.

17. The method of claim 16, further comprising: A second timing advance granularity different from the first timing advance granularity is received based on the identity of the UE, wherein the identity of the UE comprises one of an Industrial Internet of Things IIOT UE or a legacy UE.

18. The method of claim 17, wherein: The second timing advance granularity is finer than the first timing advance granularity.

19. The method of claim 18, wherein: The second timing advance granularity is preconfigured or received in a separate message from the timing advance command.

20. An apparatus for wireless communication by a base station, comprising: Memory; as well as at least one processor coupled to the memory and configured to: sending a downlink transmission including the timing information to a user equipment UE via unicast; receiving an uplink transmission from the UE subsequent to the downlink transmission; determining an RTT compensation associated with the timing information based on a round trip time (RTT) between the downlink transmission and the uplink transmission; as well as The RTT compensation is transmitted to the UE.

21. The apparatus of claim 20, wherein: The downlink transmission including the timing information sent via unicast comprises a Radio Resource Control, RRC, message.

22. The apparatus of claim 20, wherein the at least one processor is further configured to: The timing information is received from a time sensitive network TSN.

23. The apparatus of claim 20, wherein: The timing information indicates information associated with a start of a frame of the downlink transmission.

24. The apparatus of claim 20, wherein the at least one processor is further configured to: The timing information is adjusted based on the RTT compensation.

25. The apparatus of claim 20, wherein: The RTT compensation includes a timing advance associated with an adjustment of the timing information transmitted to the UE.

26. A device for wireless communication by a user equipment UE, comprising: Memory; as well as at least one processor coupled to the memory and configured to: receiving a downlink transmission including timing information from a base station via unicast; sending an uplink transmission to the base station subsequent to the downlink transmission; as well as An RTT compensation for the timing information is determined based on a round trip time (RTT) between the downlink transmission and the uplink transmission.

27. The apparatus of claim 26, wherein: The downlink transmission including the timing information received via unicast includes a Radio Resource Control, RRC, message.

28. The apparatus of claim 26, wherein: The timing information indicates information associated with a start of a frame of the downlink transmission.

29. The apparatus of claim 26, wherein: The RTT compensation includes a timing advance for adjusting the timing information received from the base station.

30. The apparatus of claim 29, wherein the at least one processor is further configured to: The timing information is adjusted based on the RTT compensation, and the adjusted timing information is delivered to an upper layer of the UE.

31. A method for wireless communication at a user equipment UE, comprising: receiving timing information from a base station via unicast; sending an uplink transmission to the base station following a downlink transmission from the base station; as well as An RTT compensation associated with adjusting the timing information is determined based on a round trip time (RTT) measured using the downlink transmission and the uplink transmission.

32. The method of claim 31, wherein: The timing information received via unicast comprises a Radio Resource Control, RRC, message.

33. An apparatus for wireless communication at a user equipment UE, comprising: Memory; as well as at least one processor coupled to the memory and configured to: receiving timing information from a base station via unicast; sending an uplink transmission to the base station following a downlink transmission from the base station; as well as An RTT compensation associated with adjusting the timing information is determined based on a round trip time (RTT) measured using the downlink transmission and the uplink transmission.

34. The apparatus of claim 33, wherein: The timing information received via unicast comprises a Radio Resource Control, RRC, message.

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