Methods for maintaining synchronization accuracy in NR IIOT and user equipment

Abstract

A method for maintaining finer synchronization requirements (e.g., less than 1 μs synchronization) between a synchronization master clock and a UE clock in NR IIOT is disclosed. This disclosure introduces a method for applying UE clock updates according to UL timing advance reception time. This disclosure also introduces a new signaling to indicate a scheduling request ID for propagation delay change and, based thereon, signaling to trigger timing advance to maintain finer synchronization requirements between a synchronization master and a UE clock. This disclosure also introduces a new method for calculating propagation delay changes at the UE (900) and thereby performing propagation delay compensation to maintain finer synchronization requirements between a synchronization master and a UE clock.

Description

[Technical Field]

[0001] This disclosure generally relates to wireless telecommunications, and in particular to maintaining finer synchronization requirements between the synchronous master clock and UE clock in the NR IIOT (New Radio Industrial Internet of Things). [Background technology]

[0002] In NR IIOT, some applications require more precise clock synchronization between the synchronous master clock and the UE clock. The synchronization requirements between the synchronous master clock and the UE clock in these applications are at the microsecond (μs) level. The clock synchronization requirements for various NR IIOT applications are listed in Table 1 (Table 6.3.1-2 of TS 38.825-g00)[1]. [Table 1]

[0003] Table 1 shows that NR IIoT requires 1 μs of synchronization in two scenarios. This requirement means that all UE clocks within a communication group are synchronized within a finer synchronization accuracy (e.g., 1 μs or 10 us depending on the application) with respect to the synchronization master. In TSN, the synchronization master may be the TSN Grandmaster (TSN GM) clock. In this document, the terms synchronization master and TSN GM clock are used interchangeably.

[0004] Generally, due to inaccuracies in the UE crystal oscillator, the UE clock drifts over time. Reference time information (T_Ref) using System Information Block (SIB) 9 may be periodically sent from the gNB to correct for time drift. As shown in Figure 1, (time T BS The T_Ref sent to is received by the UE after a propagation delay (PD).

[0005] For example, 1μs synchronization means that the two UE clocks must be within + / - 1μs of the reference time. As shown in Figure 1, the UEs are at different distances from the gNB. m and UE n These two UEs can receive reference times transmitted from the gNB at different times. To meet the specified requirements of NR IIOT, these two UEs must have an accuracy of within + / - 1 μs from the TSN GM clock.

[0006] The precision of a UE clock is specified using a metric called "parts per million (ppm)". 1 ppm means that there is a potential error of one part per million. In other words, for every million microseconds the clock runs, there is a possibility that the clock has drifted by 1 μs. For example, for every second the UE clock runs, there is a possibility that it has drifted by 1 μs. For a UE with precision of 0.1 ppm, the clock may have drifted by 1 μs every 10 seconds.

[0007] If the UE receives reference time information before a 1μs time shift occurs, finer synchronization requirements (e.g., 1μs) between the grandmaster clock and the UE clock can be met. This means that the gNB may have to transmit reference time information using either an SIB9 or an RRC DLInformationTransfer message. If reference time information is delivered using SIB9, the gNB must transmit an SIB9 at least every 5120ms (with an SIB period of less than 10000ms according to TS 38.331).

[0008] The propagation delay (PD) for a UE located 300m from the gNB is 1μs. Since different UEs within a communication group can be at different distances from the gNB, reference time information is provided to all UEs simultaneously. However, finer synchronization requirements (e.g., 1μs synchronization) between the UE clock and the TSN GM clock are not possible unless the propagation delay is compensated for while applying UE clock updates.

[0009] In summary, finer synchronization requirements (e.g., 1 μs) between the TSN GM clock and the UE clock can be achieved using propagation delay compensation (PDC). The following describes the procedure / steps for updating the UE clock to achieve and maintain finer synchronization requirements using PDC. 1. gNB sets the UE using SSB measurement timing settings (SMTC) and SRS settings, which utilize parameters such as periodicity, offset, and subcarrier spacing. 2. The UE monitors different SSB beams and performs beam measurements. Based on the measurement results, the UE can feed back beam measurement reports to the gNB to assist in changing the TX beam or RX beam at the gNB. Changes to the RX beam: Due to the multipath environment of the wireless medium / channel, the same TX beam from the gNB may be received by the UE from multiple spatial directions. Each beam received in each spatial direction is called an RX beam. To select a stronger RX beam, the UE monitors beams in all 360 degrees of spatial directions and can select the strongest RX beam, which is called the serving RX beam. The UE continues to track beams in all spatial directions to select an even stronger beam. For the same TX beam, the UE can switch to a stronger RX beam if there is one available, and the RX beam switching may not depend on the gNB. Different TX / RX beams may have different propagation delays, so changing the TX / RX beam may lead to a change in propagation delay. Since timing advance is directly proportional to propagation delay, a change in propagation delay may lead to a change in timing advance. 3. The UE periodically sends SRS according to the settings from the gNB. With the help of the received SRS, the gNB can detect changes in propagation delay. If the detected change in propagation delay exceeds a certain threshold (depending on the gNB implementation), the gNB can trigger a TA command to the UE. 4. gNB transmits reference time information via SIB9 messages. The period of SIB9 depends on the gNB implementation. 5. Upon receiving reference time information from the gNB, the UE updates its clock as TRef + PD + delta. Here, delta is the difference between the UE clock value of the UE clock update instance and the UE clock value at the TRef reception timing. Here, PD = 0.5 * N TA *T C , N TA This is a TA command received from gNB, T C This is 0.509 ns.

[0010] From the above procedure, it is clear that reference time information and PD are required to update the UE clock. Maintaining finer synchronization requirements depends on the accuracy of T_Ref and PD. Since T_Ref is received periodically from the gNB, its accuracy can be assumed to be within acceptable limits. However, PD may change due to other factors such as beam changes or path changes. The factors that affect PD changes and the problems that may arise in maintaining 1μs synchronization between the TSN GM and the UE clock are described below.

[0011] Note: In the context of this specification, the terms “reference time information,” “reference time information,” and “reference time” are used interchangeably. Unless otherwise specified, all these terms refer to reference time information.

[0012] Note: In the context of this specification, the terms "TSN GM clock" and "TSN GM" are used interchangeably. Unless otherwise specified, all these terms refer to a TSN GM clock.

[0013] Maintaining the synchronization requirement (e.g., 1 μs) between the TSN GM clock and the UE clock: PD = 0.5 * N TA *T C From this, it can be seen that PD is proportional to the timing advance (N TA ) command. Although PD can be calculated from TA, due to changes in the beam, the propagation delay changes, and the PD calculated from the previously received TA command may not be accurate.

[0014] Unless the UE receives an updated TA command from the gNB when the beam changes, the TA may not be accurate. However, in some scenarios, after the beam change occurs, the UE may not be transmitting UL signals, so there may be a delay in receiving the TA command from the gNB. In other words, every time there is a change in the propagation delay at the UE, the update of the TA command from the gNB may depend on the periodicity of the SRS (Sounding Reference Signal).

[0015] Furthermore, since the UE may be able to switch beams based on the periodicity of measurements (which depends on the periodicity of the SSB), the beam change at the UE may indirectly depend on the periodicity of the SSB.

[0016] As described above based on the accuracy of the crystal oscillator, the gNB may transmit reference time information before the UE clock drifts by more than 1 μs.

[0017] In summary, finer synchronization requirements may be achieved through propagation delay compensation, but maintaining 1 μs synchronization between the TSN GM clock and the UE clock may depend on the periodicity of SIB9 and how quickly the UE transmits SRS after a beam change.

[0018] Considered issues in maintaining finer synchronization requirements: Since the SRS periodicity is primarily designed for other purposes, it is not always feasible to specifically set the SRS periodicity to maintain a 1μs synchronization between the TSN GM and the UE clock. For this algorithm, it is necessary to design it to maintain a 1μs synchronization in all possible configuration scenarios. Further analysis of the following scenarios is possible. Scenario 1: SRS periodicity is smaller than SIB9 periodicity. Scenario 2: SRS periodicity is greater than SIB9 periodicity.

[0019] To analyze the potential problems in maintaining finer synchronization requirements, such as 1μs synchronization, consider the following configuration examples. These configuration examples are used to illustrate the timeline of UE clock updates.

[0020] Note: Some configuration parameters are provided to the UE via slots, but in this specification they are described in milliseconds (ms).

[0021] Setting 1: SCS: 60kHz; SSB period: 80ms; and offset: 0ms; SRS period: 80ms; Offset: 20ms; SIB 9 period: 640ms; offset: 50ms; The update of the UE clock is shown in Figure 2.

[0022] In this scenario, although there is a PD change (at 640ms), if the UE receives the reference time information (at 690ms), the updated TA command has already been received by the UE before the reference time information was received (at 670ms). Therefore, there is no problem in this scenario.

[0023] Setting 2: SCS: 60kHz; SSB period: 80ms; and offset: 0ms; SRS period: 80ms; offset: 20ms; SIB 9 period: 640ms; offset: 10ms. Figure 3 shows the UE clock update for setting 2.

[0024] In the diagram for setting 2's UE clock update, the PD change occurred at 640ms, and the last received TA was at 350ms. Because the UE did not have the correct PD when the reference time information was received (650ms), the UE clock update at 650ms may fail to synchronize by 1μs. [Prior art documents] [Non-patent literature]

[0025] [Non-Patent Document 1] [1] 3GPP(registered trademark) TR 21.905: "Vocabulary for 3GPP(registered trademark) Specifications" V15.0.0 (2018-03). [Non-Patent Document 2] [2] 3GPP(registered trademark) TS 38.331: "Radio Resource Control (RRC) protocol specification" V15.7.0. [Non-Patent Document 3] [3] 3GPP(registered trademark) TS 38.133: "Requirements for support of Radio Resource Management" [Non-Patent Document 4] [4] 3GPP(registered trademark) TS 38.211: "Physical Channels and Modulation" V15.7.0 [Non-Patent Document 5] [5] 3GPP(registered trademark) TS 38.212: "Multiplexing and Channel Coding" V15.7.0 [Non-Patent Document 6] [6] 3GPP(registered trademark) TS 38.213: "Physical layer procedures for control" V15.7.0 [Non-Patent Document 7] [7] 3GPP(registered trademark) TS 38.214: "Physical Layer Procedure for Data" V15.7.0 [Non-Patent Document 8] [8] 3GPP(registered trademark) TS 38.321: "Media Access Control (MAC) Protocol Specification" V15.7.0 [Non-Patent Document 9] [9] 5G NR: "Next-Generation Wireless Technology" Eric Dahlman, Stefan Parkvall, Johan Skold [Patent Documents]

[0026] [Patent Document 1]

[10] European Patent Application Publication No. 2829099 [Overview of the Initiative] [Problems that the invention aims to solve]

[0027] In NR IIOT, some applications require finer synchronization between UEs within a communication group. In other words, the TSN GM clock and all UE clocks within the communication group need to have a synchronization accuracy of + / - x us (e.g., x=1). To achieve this, the reference time (T_Ref) of the TSN GM clock must be broadcast to all UEs within the communication group.

[0028] The propagation delay (PD) for a UE located 300m from the gNB is 1μs. Since different UEs within a communication group can be at different distances from the gNB, finer synchronization requirements between the UE clock and the TSN GM clock are not possible unless the propagation delay is compensated for when applying the received reference time information.

[0029] One agreed-upon method for calculating propagation delay for propagation delay compensation is to use TA commands.

[0030] The UE clock can drift due to crystal oscillator inaccuracies. Propagation delay can vary due to the time variability of the radio channel. These two aspects make maintaining finer synchronization requirements difficult.

[0031] When a UE receives a T_Ref from a gNB and applies a UE clock update, in some scenarios, there may or may not be an accurate PD value, depending on whether there is a PD change and whether the UE receives the latest TA command corresponding to the PD change. Unless the accurate PD value is applied to compensate for the propagation delay of the UE clock update, NR IIOT applications may not be able to maintain finer synchronization requirements. [Means for solving the problem]

[0032] This disclosure provides an improved system and method for clock synchronization. More specifically, this disclosure relates to a method for maintaining a synchronization accuracy of 1 μs in NR IIOT.

[0033] Accordingly, in one embodiment, the present invention provides a method for maintaining finer synchronization requirements (e.g., 1 μs or 10 μs) between the TSN GM (Time-Sensitive Networking Grand Master) clock and the UE clock of the user equipment. (R) The system receives reference time information (T_Ref) and a TA (Timing Advance) command from an AN node and calculates the propagation delay (PD) from the TA command. If no PD change is detected after receiving the TA command but before receiving the reference time information, a UE clock update is applied; in this case, the UE clock update is applied when the reference time information is received. If a PD change is detected after receiving the TA command but before receiving the reference time information, and no update TA command is received, the UE clock update is applied when the update TA command is received.

[0034] To further clarify the advantages and features of this disclosure, specific embodiments will be described after a more detailed description of this disclosure, with reference to the accompanying figures. Please understand that these figures only illustrate typical embodiments of this disclosure and are therefore not intended to limit the scope.

[0035] This disclosure is described with additional specifics and details, along with the attached figures. [Brief explanation of the drawing]

[0036] This disclosure is further described with additional specificity and detail, accompanied by the following diagram. [Figure 1] Figure 1 shows the relevant timing relationships between different nodes within a communication group. [Figure 2] Figure 2 shows the timeline of the related UE clock updates for Configuration Example 1 (the SRS period is smaller than the period of the reference time information). [Figure 3] Figure 3 shows the relevant UE clock update timeline for Configuration Example 2 (the SRS period is smaller than the reference time information period). [Figure 4] Figure 4 is a signal diagram illustrating an embodiment that maintains finer synchronization requirements between the TSN GM clock and the UE clock. [Figure 5] Figure 5 shows the UE clock update timeline for an example configuration. [Figure 6] Figure 6 is a signal diagram illustrating another embodiment that maintains finer synchronization requirements between the TSN GM clock and the UE clock. [Figure 7] Figure 7 shows the IE for SchedulingRequestResourceId. [Figure 8] Figure 8 is a signal diagram illustrating yet another embodiment that maintains finer synchronization requirements between the TSN GM clock and the UE clock. [Figure 9] Figure 9 is a schematic block diagram of the UE. [Figure 10] Figure 10 is a block diagram schematically showing a RAN node. [Figure 11] Figure 11 is a block diagram schematically showing the core network nodes.

[0037] Furthermore, those skilled in the art will understand that elements in the figures are illustrated for simplification and may not necessarily be drawn to scale. Moreover, with respect to the configuration of the apparatus, one or more components of the apparatus may be represented in the figures by conventional symbols, and the figures may show only certain details appropriate for understanding the embodiments of this disclosure, so as not to obscure the figures with details that would be readily apparent to those skilled in the art who possess the advantages described herein. [Modes for carrying out the invention]

[0038] Herein, embodiments will be described with reference to the accompanying drawings. However, this disclosure may be embodied in many different forms and should not be construed as being limited to the embodiments described herein. Rather, these embodiments are provided to fully convey to those skilled in the art that this disclosure is thorough and complete. The terms used in the detailed description of the specific exemplary embodiments shown in the accompanying drawings are not intended to be limiting. In the drawings, similarity numbers refer to similar elements.

[0039] However, it should be noted that the reference numbers in the claims refer only to typical embodiments of the subject matter and should not be considered to limit its scope, as the subject matter may recognize other equivalent valid embodiments.

[0040] This specification may refer to "an," "one," or "some" embodiments in several places. This does not necessarily mean that each such reference refers to the same embodiment (singular or plural) or that its features apply only to a single embodiment. It is also possible to provide other embodiments by combining single features from different embodiments.

[0041] When used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless otherwise specified. Furthermore, when used herein, the terms “includes,” “comprises,” “including,” and / or “comprising” specify the presence of a described feature, integer, step, operation, element, and / or component, but are understood not to exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. When an element is referred to as “connected” or “combined” with another element, it is understood that it may be directly connected or combined with the other element, or there may be an intervening element. Furthermore, as used herein, “connected” or “combined” may include those that are operationally connected or combined. The terms “and / or” as used herein include any combination and arrangement of one or more related listed items.

[0042] Unless otherwise specified, all terms used herein (including technical and scientific terms) have the same meaning as that generally understood by a person skilled in the art relating to this disclosure. Furthermore, terms as defined in commonly used dictionaries should be interpreted as having a meaning consistent with that in the context of the relevant art, and it will be understood that they should not be interpreted in an idealized or overly formal sense unless expressly defined herein.

[0043] The diagram shows a simplified structure that illustrates only a few elements and functional entities; all are logical units, and their implementation may differ from that shown. The connections shown are logical connections, and actual physical connections may differ. It will be obvious to those skilled in the art that the structure may also include other functions and structures.

[0044] Furthermore, all logical units described and depicted in the diagram include the software and / or hardware components necessary for the unit to function. In addition, each unit may contain one or more implicitly understood components within itself. These components may be operably coupled to one another and configured to communicate with one another in order to perform the functions of the unit.

[0045] First embodiment: The first embodiment describes a novel method for maintaining finer synchronization requirements (e.g., synchronization of less than 1 μs) between the TSN GM clock and the UE clock in order to solve problem statement 1. An overview of the solution procedure is shown in Figure 4 and is described below. 401. (R) Reference time information from AN nodes or gNBs SRS transmission via 402.UE 403.(R)TA commands via AN node or gNB 404.UE Clock Update

[0046] The first embodiment will be described below as a first example. 1. In step 401, the UE receives reference time information (T_Ref) from the gNB. Reference time information can be transmitted periodically via SIB 9 or via RRC signaling using the RRC DLInformationTransfer message. The period of SIB 9 varies depending on the gNB implementation. In step 401, the UE received reference time information, but because the UE may or may not know the exact PD, the UE clock update may not be applied immediately after receiving the reference time information. 2. In step 402, the UE sends an SRS according to the SRS settings received from the gNB. 3. In step 403, when the gNB receives an SRS from the UE, it may detect a PD change from the SRS. If the detected PD change exceeds a certain threshold (up to the gNB implementation), the gNB may trigger a TA command to the UE. The gNB may not send a TA command with every SRS transmission. Whether an SRS transmission may trigger a TA command from the gNB may depend on the PD change and the gNB implementation. 4. In step 404, the UE calculates the PD from the TA command received in step 403. The calculated PD is equal to half the TA value. The UE applies a UE clock update based on the following principle: a. If no PD change is detected after receiving a TA command but before receiving reference time information, the UE applies a UE clock update when it receives reference time information. b. If a PD change is detected after receiving a TA command but before receiving reference time information, and an update TA command is not received, the UE will apply a UE clock update when an update TA command is received. In other words, the UE can wait for the update TA command to be received. Furthermore, when the UE receives an update TA command, it updates the clock with T_Ref+PD+delta. Here, delta is the difference between the UE clock value at the time of the UE clock update and the UE clock value at the time of receiving the reference time information. Furthermore, the UE can detect PD changes based on the detection of beam changes or path changes, and the PD change is calculated as the difference between the UE DL timing at the time of the beam change or path change and the UE DL timing at the time of TA command reception.

[0047] The first embodiment will be described below as a second example. 1. In step 401, as described in the first example of this embodiment, the UE periodically receives reference time information via SIB 9 or via RRC signaling using RRC DLInformationTransfer messages.

[0048] In addition to receiving reference time information, the UE also receives an RRC reset message from the gNB. Through the RRC reset message, the gNB provides the UE with the SSB measurement timing configuration (SMTC) and the SRS configuration, which includes parameters such as period, offset, and subcarrier spacing. The gNB then transmits the SSB signal according to the configured settings. In accordance with the received RRC reset message, the UE monitors different SSB beams and performs beam measurements. Based on the beam measurement results, the UE can feed back a beam measurement report to the gNB to assist with TX beam changes at the gNB. Due to the multipath environment of the radio medium / channel, the same TX beam from the gNB may be received by the UE in multiple spatial directions. The beam received in each spatial direction is called one RX beam. To select a stronger RX beam, the UE can monitor beams in all 360 spatial directions and select the stronger RX beam, which is called the serving RX beam. The UE further continues to track beams in all spatial directions for any possible stronger beams. For the same TX beam, the UE can change the RX beam if there is a stronger RX beam than the service RX beam, and the RX beam switching may not be dependent on the gNB. Since different TX / RX beams may have different propagation delays, changing the TX / RX beam may lead to a change in PD. Since the timing advance is directly proportional to the propagation delay, a change in PD may lead to a change in the timing advance. 2. In step 402, the UE transmits an SRS according to the SRS settings received in step 401. 3. In step 403, upon receiving an SRS from the UE, the gNB can detect a PD change from the SRS. If the detected PD change exceeds a certain threshold (up to the gNB implementation), the gNB can trigger a TA command to the UE. The gNB may not send a TA command for every SRS transmission. The SRS transmissions that may trigger a TA command from the gNB may depend on the PD change and the gNB implementation. 4. In step 404, the UE calculates the latest PD from the TA command received in step 403. The UE applies a UE clock update based on the following principle: a. If no PD change is detected after receiving a TA command but before receiving reference time information, the UE applies a UE clock update when it receives reference time information. b. If a PD change is detected after receiving a TA command but before receiving reference time information, and an update TA command is not received, the UE will update the clock when it receives the update TA command. In other words, the UE can wait for the update TA command. Furthermore, when the UE receives an update TA command, it updates its clock with T_Ref+PD+delta. Here, delta is the difference between the UE clock value at the time of the UE clock update and the UE clock value at the time of receiving the reference time information.

[0049] The first embodiment will be described using the following example settings, also shown in Figure 5.

[0050] Example settings: SCS: 60kHz; SSB period: 80ms; and offset: 0ms; SRS period: 80ms; offset: 20ms; SIB 9 period: 640ms; offset: 10.

[0051] In this example, the gNB transmits SSB every 80ms. According to the configuration, the UE monitors the SSB beam every 80ms and performs beam management. If the RX beam is stronger than the serving TX beam, the UE performs a beam switch. In the diagram, instances of RX beam switching are shown in dark red.

[0052] In this example, the UE transmits SRS at 80ms intervals. Upon receiving SRS from the UE, the gNB estimates the PD change. If the PD change exceeds a certain threshold, the gNB sends a TA command to the UE.

[0053] As shown in Figure 5, there are PD changes at 320ms and 640ms, and SRS transmissions occur after the PD changes at 340ms and 660ms. Due to the PD changes occurring at 320ms and 640ms, they may be independent of the gNB. The gNB may be able to detect the PD changes using the SRS transmissions at 340ms and 660ms. If the gNB detects the PD changes using the SRS, it can trigger TA commands at 350ms and 670ms.

[0054] With a 640ms SIB9 period and a 10ms offset, the gNB transmits SIB9 at 10ms and 650ms. As shown in Figure 5, the PD change occurs at 640ms, and the last received TA is at 350ms. If the UE clock is updated at 640ms with the PD calculated from the last received TA command (at 350ms), the UE PD will be inaccurate and may fail to synchronize by 1μs. To avoid this, the UE clock update is applied when the updated TA command is received. In this example, the reference time information is received at 650ms, but the PD change is detected at 640ms, so after receiving the updated TA command, the UE clock is updated at 670ms.

[0055] Second embodiment: The second embodiment describes a novel UE-assisted and gNB-based method for maintaining finer synchronization requirements (e.g., synchronization of less than 1 μs) between the GM clock and the UE clock to solve problem statement 1. An overview of the solution procedure is shown in Figure 6 and is described below. 601. (R) Reference time information from AN nodes or gNBs Scheduling request by 602.UE 603.(R)TA commands via AN node or gNB 604.UE Clock Update

[0056] In some scenarios, a second embodiment is described as a first example.

[0057] 1. In step 601, the UE receives reference time information from the RAN node. Reference time information can be received via SIB9 or RRC DLInformationTransfer messages. 2. In step 602, the UE detects a change in PD due to a change in the RX beam or a change in the path. If there are no available SRS resources within a certain time after SRS transmission, or if a TA command is not received within a certain time, the UE sends a scheduling request indicating the PD change to the gNB. If the UE is waiting for a TA command after the PD change, the UE does not apply a UE clock update even though it has received reference time information. The scheduling request procedure indicating the PD change is performed as described below. a. In this method, when a change in the PD is detected, the UE sends a scheduling request (using a new scheduling request ID) to the gNB indicating the change in the PD. When the gNB detects the new scheduling request ID, the gNB determines the purpose of the scheduling request as a change in the PD from the scheduling request ID. b. Scheduling requests are submitted according to the existing procedures specified in TS 38.213. c. In this method, a new type of SchedulingRequestResourceId called SchedulingRequestIDForPropDelayChange is introduced in the SchedulingRequestResourceConfig IE of TS 38.331 to indicate PD changes in the UE due to RX beam changes, path changes, or other reasons. The IE is shown in Figure 7 It will be provided to. Here, IE SchedulingRequestResourceId is an integer, and each SchedulingRequestResourceId ID is used to identify the scheduling request resource on PUCCH for various purposes. For example, SchedulingRequestResourceId=1 is purpose #1 (e.g., purpose #1 is an uplink permission request). In this case, SchedulingRequestResourceId=1 indicates the purpose of scheduling the request as an uplink permission request, while SchedulingRequestResourceId=5 is purpose #2 (e.g., purpose #2 is a PD change instruction). In this case, SchedulingRequestResourceId=5 indicates the purpose of scheduling the request as a PD change, etc. This mapping between SchedulingRequestResourceId and the purpose used can be implicitly or explicitly configurable and is recognized by both the gNB and the UE. Based on the purpose that triggered the UE to send a scheduling request to the gNB, the UE sends the scheduling request using the SchedulingRequestResourceId. When the gNB encounters the SchedulingRequestResourceId, the gNB determines the purpose based on the SchedulingRequestResourceId. d.UE can be configured using a PUCCH resource by schedulingRequestResourceId or schedulingRequestIDForPropDelayChange to indicate a gNB related to a PD change. Here, IE SchedulingRequestResourceId or IE schedulingRequestIDForPropDelayChange is used to identify the scheduling request resource on the PUCCH configured for the PD change instruction. e.UE can be set in schedulingRequestIDForPropDelayChange using either PUCCH format 0 or PUCCH format 1. Based on the reception cycle of reference time information and changes in channel conditions, in some scenarios the UE may receive reference time information before sending a scheduling request, while in some other scenarios the UE may send a scheduling request before receiving reference time information. The sending of scheduling requests from the UE to indicate PD changes may depend on beam changes or path changes. Furthermore, PD changes are calculated as the difference between the UE DL timing at the time of beam change or path change and the UE DL timing at the time of receiving the TA command (the last TA command before the beam change or path change). 3. In step 603, the gNB detects the scheduling request sent by the UE. From the scheduling request resource configuration, the gNB recognizes the specific PUCCH-ResourceId set for schedulingRequestIDForPropDelayChange. Once the gNB detects the specific PUCCH resource ID, it can learn about the PD change. If the gNB can detect a timing change from the received scheduling request, it sends a TA command. 4. In step 604, upon receiving the TA command, the UE calculates the PD from the TA command. The calculated PD is equal to half the TA value, as follows: When a UE receives a TA command and the UE has received reference time information (T_Ref) from the gNB, the UE applies a UE clock update using T_Ref + PD + delta. Here, delta is the difference between the UE clock value at the time of the UE clock update and the UE clock value at the time of receiving the reference time information. If the UE receives reference time information after sending SchedulingRequestIDForPropDelayChange but before receiving the updated TA command, the UE applies the UE clock update when it receives the updated TA command. If the UE does not receive reference time information before receiving the updated TA command, the UE updates the PD based on the updated TA command and applies the UE clock update when it receives reference time information from the gNB.

[0058] In some scenarios, the gNB may fail to detect changes in the PD or timing from the scheduling request. Solutions to these scenarios are described below as a second example. 1. In step 601, the UE receives reference time information from the RAN node or gNB. Reference time information can be received via SIB9 or RRC DLInformationTransfer message. 2. In step 602, the UE sends a scheduling request in accordance with the procedure described in step 2 of the first example of the second embodiment. 3. In step 603, the gNB detects the scheduling request sent by the UE. Although the scheduling request is detected by the gNB, the gNB may not be able to detect a change in PD or timing from the scheduling request. In these scenarios, the gNB schedules a non-periodic SRS to the UE and estimates the change in TA. 4. In step 604, the UE uses the SRS resources received with the non-periodic SRS scheduling permission to send SRS transmissions in the scheduled time slots. If the gNB can detect a PD change from the SRS transmission and the PD change exceeds a threshold (which may be the gNB implementation), the gNB sends a TA command to the UE. Upon receiving the TA command, the UE calculates the PD and does the following: When a TA command is received, if the UE has received reference time information (T_Ref) from the gNB, the UE applies a UE clock update using T_Ref + PD + delta. Here, delta is the difference between the UE clock value at the time of the UE clock update and the UE clock value at the time of receiving the reference time information. PD is the received update TA command. If the UE receives reference time information after sending schedulingRequestIDForPropDelayChange but before receiving the update TA command, the UE applies the UE clock update when it receives the update TA command. If the UE does not receive reference time information before receiving the update TA command, the UE updates the PD and applies the UE clock update when it receives the reference time information.

[0059] Third embodiment: The third embodiment describes a novel UE-based method in which the UE calculates the propagation delay (PD) based on the last TA received from the gNB without waiting for an updated TA command, in order to maintain finer synchronization requirements (e.g., synchronization of less than 1 μs) between the GM clock and the UE clock to solve problem statement 1. An overview of the solution procedure is shown in Figure 8 and is described below. 801.(R) TA commands via AN node PD calculation using 802.UE 803. (R) Reference time information from AN nodes or gNBs 804.UE Clock Update

[0060] The detailed solution process is explained below. 1. In step 801, the gNB sends a TA command whenever it detects a beam change or a PD change or timing change due to other reasons. 2. In step 802, the UE calculates the propagation delay (PD) by calculating the difference in propagation delay relative to the serving beam. The calculation of PD will be explained using the following example. In this example, assuming beam X is the serving beam, its PD is PD beamX =0.5*N TA *T c It can be expressed as follows: In this case, N TA This is the latest TA command corresponding to serving beam X. The PD for beam Y is PD beamY =PD beamX +T path_diff_beamY It can be calculated as follows: Here, T path_diff_beamY This is the propagation delay difference between RX beam Y and RX beam X (serving beam). Since the UE may need to measure different RX beams in different spatial directions during each SMTC period, the UE can only measure a specific spatial direction / RX beam. Each time the UE measures in an RX beam direction, it can calculate the timing for that direction. The next moment the UE measures the timing for that direction could be 8*SMTC periods later (assuming the UE measures in 8 distinct spatial directions). Because channel conditions differ, the UE may perform an RX beam switch to a particular RX beam before that beam is measured again; therefore, it is necessary to have a way to recognize the path difference of a particular RX beam at all times. One way to know the nearly accurate path difference of an RX beam wrt serving beam at any given time is to have a weighted average of the path differences of all RX beam wrts for the serving beam that received the TA command. This can be achieved by forward computing the path difference of the RX beams as the UE measures and stores it in a particular RX beam direction. Since this is forward computed and the PD may have changed slightly compared to the time it was last measured, it may be useful to take a weighted average to eliminate any erroneous deviation from the actual path difference. The forward-computed weighted average of the path difference of beam Y at time t is T' path_diff_beamY It is given by (t). This can be calculated as follows: Note TIFF0007896629000002.tif30150: If any beam cannot be detected, the UE resets the path difference calculation wrt for that beam and resumes the path difference calculation when the beam becomes detectable again. Weighted averages may be used as an optional feature depending on the scenario / application. 3. In step 803, reference time information is transmitted by the gNB and received by the UE. 4. In step 804, when the UE receives reference time information (T_Ref) from the gNB, the UE applies a UE clock update using T_Ref + PD + delta. Here, delta is the difference between the UE clock value at the time of the UE clock update and the UE clock value at the time of receiving the reference time information, and the PD calculated in step 802 is applied here.

[0061] User Equipment (UE) Figure 9 shows a block diagram illustrating the main components of UE(900). As shown, UE(900) includes a transceiver circuit (902) capable of transmitting and receiving signals to and from one or more nodes (one or more) connected via one or more antennas (901). While not necessarily shown in Figure 1, UE(900) of course has all the usual functions of a conventional mobile device (such as a user interface), which can be provided by hardware, software, firmware, or any combination thereof, as needed. Software may be pre-installed in memory, or it may be downloaded, for example, over a telecommunications network or from a removable data storage device (RMD).

[0062] The controller (904) controls the operation of the UE (900) according to software stored in memory (905). For example, the controller is implemented by a central processing unit (CPU). The software includes, among other things, an operating system and a communications control module having at least a transmit / receive control module. The communications control module (using transmit / receive control submodules) is responsible for signaling and processing (generating / transmitting / receiving) uplink / downlink data packets between the UE and other nodes (such as base stations / (R)AN nodes, MMEs, AMFs (and other core network nodes)). Such signaling includes, for example, properly formatted signaling messages regarding connection establishment and maintenance (e.g., RRC messages), and NAS messages such as periodic location update-related messages (e.g., tracking area updates, paging area updates, location area updates).

[0063] (R)AN node Figure 10 is a block diagram showing the main components of an exemplary (R)AN node (1000), for example, a base station (eNB in ​​LTE, gNB in ​​5G). As illustrated, the (R)AN node (1000) includes a transceiver circuit (1002) capable of transmitting and receiving signals to and from one or more UEs connected via one or more antennas (1001), and transmitting and receiving signals to and from other network nodes (directly or indirectly) via a network interface (1003). A controller (1004) controls the operation of the (R)AN node (1000) according to software stored in memory (1005). For example, the controller (1004) is implemented by a central processing unit (CPU). The software may be pre-installed in memory (1005) and / or may be downloaded, for example, via a telecommunications network or from a removable data storage device (RMD). The software includes, among other things, an operating system and a communication control module having at least a transceiver control module.

[0064] The communication control module (using transmit / receive control submodules) is responsible for processing (generating / transmitting / receiving) signals (e.g., directly or indirectly) between (R)AN nodes and other nodes such as UEs, MMEs, and AMFs. Signaling may include, for example, appropriately formatted signaling messages relating to radio connectivity and location procedures (for a particular UE), particularly messages relating to connection establishment and maintenance (e.g., RRC connection establishment, other RRC messages), periodic location update-related messages (e.g., tracking area updates, paging area updates, location area updates), S1 AP messages and NG AP messages (i.e., messages from the N2 reference point). Such signaling may also include, for example, broadcast information in the transmission case (e.g., master information, system information).

[0065] Furthermore, the controller (1004), if implemented, is configured (by software or hardware) to handle related tasks such as UE mobility estimation and / or movement trajectory estimation.

[0066] Core network node Figure 11 is a block diagram showing the main components of an exemplary core network node (1100), such as an AMF, SMF, SEAF, AUSF, UPF, UDM, ARPF, or any other core network node. The core network node (1100) is included in 5GC. As shown, the core network node includes a transmit / receive circuit (1101) that can operate to send and receive signals with other nodes (including UEs) via a network interface (1104). A controller (1102) controls the operation of the core network node (1100) according to software stored in memory (1103). For example, the controller (1102) is implemented by a central processing unit (CPU). The software may be pre-installed in memory (1103) and / or may be downloaded, for example, via a telecommunications network or from a removable data storage device (RMD). The software includes, among other things, an operating system and a communications control module having at least a transmit / receive control module.

[0067] The communication control module (using transmit / receive control submodules) is responsible for processing (generating / transmitting / receiving) (direct or indirect) signaling between the core network node and other nodes such as UEs, base stations / (R)AN nodes (e.g., "gNB" or "eNB"). Such signaling includes, for example, appropriately formatted signaling messages related to the procedures described herein, such as NG AP messages (i.e., messages from the N2 reference point) for transmitting NAS messages to UEs, etc.

[0068] In this disclosure, user equipment (or "UE," "mobile station," "mobile device," or "wireless device") is an entity connected to a network via a wireless interface.

[0069] Furthermore, the term UE in this specification is not limited to dedicated communication devices, but can be applied to any device having communication functions as a UE as described in this specification, as explained in the following paragraphs.

[0070] The terms “User Equipment” or “UE” (a term used in 3GPP®), “Mobile Station,” “Mobile Device,” and “Wireless Device” are generally intended to be synonymous with each other and include standalone mobile stations such as terminals, mobile phones, smartphones, tablets, cellular IoT devices, IoT devices, and machinery.

[0071] It is recognized that the terms "UE" and "wireless device" also include devices that remain stationary for extended periods.

[0072] UE can be, for example, products of equipment for production or manufacturing and / or products of energy-related machinery (e.g., boilers, engines, turbines, solar panels, wind turbines, hydroelectric generators, thermal power generators, nuclear power generators, batteries, nuclear systems and / or related equipment, heavy electrical equipment, pumps including vacuum pumps, compressors, fans, blowers, hydraulic equipment, pneumatic equipment, metalworking machinery, manipulators, robots and / or their application systems, tools, dies or molds, rolls, conveying equipment, lifting equipment, material handling equipment, textile machinery, sewing machines, printing and / or related machinery, paper machines, chemical machinery, mining and / or construction machinery and / or related equipment, agricultural, forestry and fisheries machinery and equipment, safety and environmental protection equipment, tractors, precision bearings, chains, gears, power transmission equipment, lubrication equipment, valves, pipe fittings and / or application systems of the aforementioned equipment and machinery).

[0073] UE is, for example, a product of transportation equipment (such as railway cars, automobiles, motorcycles, bicycles, trains, buses, carts, rickshaws, ships and other surface vessels, aircraft, rockets, satellites, drones, balloons, etc.).

[0074] UE can be, for example, a product of information and communication equipment (e.g., electronic computers and related equipment, communication and related equipment, electronic components, etc.).

[0075] UEs may include, for example, refrigerators, refrigerator applications, trade and / or service industry equipment, vending machines, automated service machines, office machinery or equipment, and consumer electronics (e.g., audio equipment, video equipment, loudspeakers, radios, televisions, microwave ovens, rice cookers, coffee machines, dishwashers, washing machines, dryers, fans and related appliances, cleaners and other household appliances).

[0076] UEs can be, for example, electrical application systems or electrical equipment (such as X-ray systems, particle accelerators, radioisotope equipment, acoustic equipment, electromagnetic application equipment, and electronic power application equipment).

[0077] UEs may include, for example, electronic lamps, lighting fixtures, measuring instruments, analyzers, testers, or surveying or sensing equipment (such as smoke alarms, human alarm sensors, motion sensors, wireless tags, etc.), watches or clocks, laboratory equipment, optical instruments, medical equipment and / or systems, weapons, bladed tools, hand tools, etc.

[0078] A UE can be, for example, a personal digital assistant (PDA) or related equipment (such as a wireless card or module designed to be attached to or inserted into other electronic devices, such as a personal computer or electrical measuring instrument).

[0079] UE can be part of a device or system that uses various wired and / or wireless communication technologies to provide the applications, services, and solutions related to the Internet of Things (IoT) described below.

[0080] An Internet of Things (IoT) device (or "thing") may be equipped with appropriate electronics, software, sensors, network connectivity, etc., so that these devices can collect and exchange data with each other or with other communication devices. IoT devices may include automated equipment that follows instructions from software stored in internal memory. IoT devices can operate without requiring human supervision or operation. IoT devices may also be stationary or inactive for extended periods. IoT devices may be implemented as part of (generally) stationary equipment. IoT devices may also be integrated into non-stationary equipment (e.g., vehicles) or attached to animals or people being monitored / tracked.

[0081] It will be understood that IoT technology can be implemented in any communication device that can connect to a communication network and send and receive data, regardless of whether the communication device is controlled by human input or by software instructions stored in memory.

[0082] It will be understood that IoT devices may also be referred to as MTC (Machine-Type Communication) devices, M2M (Machine-to-Machine) communication devices, or NB-IoT UE (Narrow Band-IoT UE). It will be understood that a UE may support one or more IoT or MTC applications. Some examples of MTC applications are listed in the following table (Source: 3GPP® TS 22.368 V 13.1.0, Annex B, the contents of which are incorporated herein by reference). This list is not exhaustive and is intended to illustrate some examples of machine-type communication applications.

[0083] Table 2: Some examples of machine-type communication applications. [Table 2]

[0084] Applications, services, and solutions may include MVNO (Mobile Virtual Network Operator) services, emergency radio communication systems, PBX (Private Branch eXchange) systems, PHS / digital cordless communication systems, POS (Point of Sale) systems, advertising call systems, MBMS (Multimedia Broadcast and Multicast Service), V2X (Vehicle to Everything) systems, train radio systems, location-related services, disaster / emergency radio communication services, community services, video streaming services, femtocell application services, VoLTE (Voice over LTE) services, billing services, wireless on-demand services, roaming services, activity monitoring services, carrier / network selection services, function restriction services, PoC (Proof of Concept) services, personal information management services, ad hoc network / DTN (Delay Tolerant Networking) services, and others.

[0085] Furthermore, the above-mentioned UE categories are merely examples of the technical ideas and exemplary embodiments described in this document. Needless to say, these technical ideas and embodiments are not limited to the above-mentioned UEs and can be modified in various ways.

[0086] For example, the exemplary embodiments disclosed above, in whole or in part, may be described as follows in the appendix. (Note 1) A method performed by a UE to maintain synchronization between the TSN GM (Time-Sensitive Networking Grand Master) clock and the user equipment (UE) clock within less than 1 microsecond, (R)Receive reference time information (T_Ref) from the AN node, Upon receiving a TA (Timing Advance) command from the aforementioned (R)AN node, Calculate the PD (Propagation Delay) from the aforementioned TA command, Apply UE clock update, If no PD change is detected after receiving the TA command but before receiving the reference time information, the UE clock update is applied when the reference time information is received. A method in which, if a PD change is detected after receiving the TA command but before receiving the reference time information, and an update TA command is not received, the UE clock update is applied when the update TA command is received. (Note 2) The method according to Appendix 1, further comprising applying the UE clock update by T_Ref+PD+delta, wherein delta is the difference between the UE clock value at the time of the UE clock update and the UE clock value at the time of receiving the reference time information. (Note 3) The calculated PD is equal to half the TA value, as described in Appendix 1. (Note 4) The method according to Appendix 1, wherein a change in the PD occurs due to a beam change or path change, the PD change is detected, and the PD change is calculated as the difference between the UE DL timing at the time of the beam change or path change and the UE DL timing at the time of receiving the TA command. (Note 5) User equipment (UE), At least one transceiver and, At least one processor, Equipped with, The aforementioned processor, (R)Receive reference time information (T_Ref) from the AN node, The (R)AN node receives a TA (Timing Advance) command. From the aforementioned TA command, calculate PD (Propagation Delay). Apply UE clock update, If the UE does not detect a PD change after receiving the TA command but before receiving the reference time information, the UE clock is updated when the reference time information is received. The UE is configured to update the UE clock when it receives the update TA command, if it detects a PD change after receiving the TA command but before receiving the reference time information, and if an update TA command has not been received. (Note 6) The aforementioned UE clock update is performed using T_Ref+PD+delta, The UE according to claim 5, wherein the delta is the difference between the UE clock value at the time of the UE clock update and the UE clock value at the time of receiving the reference time information. (Note 7) The aforementioned processor, The UE described in Appendix 5 is configured to calculate the aforementioned PD as half of the TA value. (Note 8) The aforementioned processor, The UE described in Appendix 5 is configured to detect the PD change when there is a change in the beam or path, and to calculate the PD change as the difference between the UE DL timing at the time of the beam or path change and the UE DL timing at the time of receiving the TA command.

[0087] This application is based on Indian Patent Application No. 202111002014, filed on 15 January 2021, claiming the benefit of its priority, the disclosure of which is incorporated in its entirety by reference.

[0088] Abbreviation In this specification, 3GPP® TR 21.905[1] and the abbreviations set forth below apply. If an abbreviation defined herein is found in 3GPP® TR 21.905[1], that definition takes precedence. 5GC 5G Core Network 5GS 5G system 5QI 5G QoS Identifier AMF access and mobility management functions AS Access Layer ASN1 Abstract Syntax Notation 1 BWP bandwidth portion CORESET Control Resource Set CP patrol prefix CSI channel status information CSI-RS Channel Status Information - Reference Signal DL Downlink IOT (Internet of Things) for Industrial Use MAC Media Access Control MAC CE MAC control element NG-RAN Next Generation Wireless Access Network NR New Wireless / NR Wireless Access PBCH Physical Broadcasting Channel PD propagation delay PDC propagation delay compensation PDCCH Physical Downlink Control Channel PDSCH Physical Downlink Shared Channel PUCCH Physical Uplink Control Channel PUSCH Physical Uplink Shared Channel QCL Semi-Colocation (R)AN (Wireless) Access Network RRC (Radio Resource Control) RS reference signal SA NR Standalone NR SIB System Information Block SCS subcarrier spacing SR scheduling request SRS Sounding Reference Signal SS synchronization signal SSB SS / PBCH Block TA Timing Advance TCI transmission settings instructions UL Uplink OS (Operating System) MO Mobile Transmission MT Mobile Incoming Call USIM Universal Subscriber Identity Module

[0089] definition For the purposes of this specification, the terms and definitions set forth in 3GPP® TR 21.905 [1] and those set forth below shall apply. Terms defined herein shall take precedence over the definitions in 3GPP® TR 21.905 [1] where the same terms are found.

[0090] List of References [1] 3GPP(registered trademark) TR 21.905: "Vocabulary of the 3GPP(registered trademark) specification". V15.0.0 (2018-03). [2] 3GPP(registered trademark) TS 38.331: "Radio Resource Control (RRC) Protocol Specification" V15.7.0. [3] 3GPP® TS 38.133: "Requirements for Wireless Resource Management Support" [4] 3GPP(registered trademark) TS 38.211: "Physical Channels and Modulation" V15.7.0 [5] 3GPP(registered trademark) TS 38.212: "Multiplexing and Channel Coding" V15.7.0 [6] 3GPP(registered trademark) TS 38.213: "Physical layer procedures for control" V15.7.0 [7] 3GPP(registered trademark) TS 38.214: "Physical Layer Procedure for Data" V15.7.0 [8] 3GPP(registered trademark) TS 38.321: "Media Access Control (MAC) Protocol Specification" V15.7.0 [9] 5G NR: “Next Generation Wireless Technology” Eric Dahlman, Stefan Parkvall, Johan Skold

[10] EP2829099A1 Select transmission point [Explanation of Symbols]

[0091] 401 (R) Reference time information from AN node or gNB SRS transmission via 402 UE TA commands via 403 (R)AN node or gNB 404 UE Clock Update Reference time information from 601 (R)AN nodes or gNBs 602 Scheduling request by UE TA commands via 603 (R)AN node or gNB 604 UE Clock Update TA commands via 801 (R)AN node PD calculation using 802 UE Reference time information from 803 (R)AN nodes or gNBs 804 UE Clock Update

Claims

1. A method performed by a user equipment (UE) to maintain synchronization between the TSN GM (Time-Sensitive Networking Grand Matter) clock and the UE clock within less than one microsecond, (R) Receive reference time information (T_Ref) from the AN node, Upon receiving a TA (Timing Advance) command from the aforementioned (R)AN node, The PD (Propagation Delay) is calculated from the aforementioned TA command. Apply the UE clock update, If no PD change is detected after receiving the TA command but before receiving the reference time information, the UE clock update is applied when the reference time information is received. A method wherein, if a PD change is detected after receiving the TA command but before receiving the reference time information, and an update TA command is not received, the UE clock update is applied when the update TA command is received.

2. The method according to claim 1, further comprising applying the UE clock update by T_Ref + PD + delta, wherein delta is the difference between the UE clock value at the time of the UE clock update and the UE clock value at the time of receiving the reference time information.

3. The method according to claim 1, wherein the calculated PD is equal to half the TA value.

4. The method according to claim 1, wherein a change in the PD occurs due to a beam change or path change, and the change in the PD is calculated as the difference between the UE DL timing at the time of the beam change or path change and the UE DL timing at the time of receiving the TA command.

5. User equipment (UE), At least one transceiver and, At least one processor, Equipped with, The aforementioned processor, (R) Receive reference time information (T_Ref) from the AN node, The (R)AN node receives a TA (Timing Advance) command, The PD (Propagation Delay) is calculated from the aforementioned TA command. Apply the UE clock update, If the UE does not detect a PD change after receiving the TA command but before receiving the reference time information, the UE clock is updated when the reference time information is received. The UE is configured to update its clock when it receives the update TA command, if it detects a PD change after receiving the TA command but before receiving the reference time information, and if an update TA command has not been received.

6. The aforementioned UE clock update is performed using T_Ref + PD + delta. The UE according to claim 5, wherein the delta is the difference between the UE clock value at the time of the UE clock update and the UE clock value at the time of receiving the reference time information.

7. The aforementioned processor, The UE according to claim 5, configured to calculate the aforementioned PD as half of the TA value.

8. The aforementioned processor, The UE according to claim 5, configured to detect the PD change when there is a change in the PD due to a beam change or path change, and to calculate the PD change as the difference between the UE DL timing at the time of the beam change or path change and the UE DL timing at the time of receiving the TA command.

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