Method and apparatus for synchronizing devices of a wireless network

Abstract

The invention relates to a method of updating a time counter of a user equipment in a wireless network comprising a base station and a plurality of user equipments, the method comprising performing at the user equipment the following steps: receiving a reference time and an indication for determining a reference time point associated with the reference time; scheduling a determination of a propagation delay with respect to the reference time point; determining the propagation delay to the base station in accordance with the scheduling; and updating the time counter using the reference time and the determined propagation delay.

Description

Technical Field

[0001] The present invention relates to a method and apparatus for synchronizing wireless networks such as radio communication networks. Background Technology

[0002] The uses of the Internet of Things (IoT) are multiplying, with each use accompanied by specific constraints.

[0003] One application of IoT is in industry, such as in production workshops using critical machinery and multiple sensors and actuators. IoT enables precise tracking of production lines, for example, by implementing the following functions (not an exhaustive list): predictive maintenance (avoiding production interruptions by proactively scheduling maintenance interventions by identifying early signs of failure), intelligent diagnostics (by recording operational data and maintenance history via sensors), production line optimization, production machine optimization, and so on.

[0004] With the development of 5G technology, a new generation of IoT is being developed. However, it is still necessary to ensure that 5G networks are compatible with time-sensitive applications enabled by IoT components.

[0005] Therefore, accurate time synchronization is required within 5G networks.

[0006] A conventional reference system frame mechanism is proposed. The base station provides user equipment with information for time synchronization, such as a reference time linked to the occurrence of the reference system frame provided by the base station. Then, when the user equipment receives a reference frame that signals the reference time point within the reference system frame, it sets its local time counter to the reference time.

[0007] Synchronization based on the reference system frame mechanism can be improved by compensating for propagation delay (i.e., the time it takes for the reference frame to reach the user equipment).

[0008] Several solutions exist, including using a precise time protocol (IEEE 1588) suitable for 5G systems to measure the propagation delay between user equipment and base stations during location triangulation estimation.

[0009] The Precise Time Protocol (RTP) mechanism involves exchanging uplink and downlink frames between a user equipment (UE) and a base station. Both the UE and the base station then store the transmission and reception times of the exchanged frames to estimate the round-trip time (RTT). The UE then calculates the propagation delay based on the estimated RTT (or more precisely, half of it) and uses this propagation delay to update its local time counter.

[0010] Another known solution for measuring propagation delay is known as the Timing Advance (TA) mechanism, as described in TS 38.211, Clause 4.3. This mechanism is designed to control the timing of uplink frames for user equipment. Within the Timing Advance (TA) command for each user equipment, the mechanism provides a timing value correction that takes into account the estimated propagation delay for that user equipment.

[0011] To this end, the base station schedules the transmission time of uplink frames for user equipment and regularly monitors the propagation delay of these scheduled uplink frames, as the base station knows the transmission time of the frame and can detect its reception time. Then, the base station calculates the propagation delay before sharing the propagation delay (or its correction) with the user equipment using subsequent messages that may be subsequent TA commands.

[0012] However, these known mechanisms have limitations. In reality, network conditions and the location of user equipment can change significantly during time synchronization processing. In such cases, the estimated propagation delay does not adequately reflect the actual propagation delay of the reference frame, upon which the local time counter is initially set. Therefore, substantial desynchronization of the time counters may persist over time.

[0013] Therefore, a more accurate synchronization mechanism is needed. Summary of the Invention

[0014] This invention was designed to address one or more of the aforementioned problems. The invention relates to a mechanism for updating a time counter for a user equipment (UE), wherein a reference time point of a reference system frame is thereby used to schedule or trigger a measurement of propagation delay (or RTT) in a manner as close as possible to the reference time point and therefore as close as possible to the reference frame.

[0015] In other words, a dedicated method for measuring propagation delay is defined, thereby allowing proximity to the reference SFN to trigger the measurement.

[0016] A method is provided for updating a time counter of a user equipment in a wireless network, the wireless network including a base station and a plurality of user equipments, the method comprising performing the following steps at the user equipment:

[0017] Receive reference time and an indication for determining a reference time point associated with the reference time;

[0018] Determining the propagation delay relative to the reference time point;

[0019] The propagation delay with the base station is determined based on the scheduling; and

[0020] The time counter is updated using the reference time and the determined propagation delay.

[0021] According to some embodiments, the reference time point may be the end of a reference system frame, and the indication may include the sequence number of the reference system frame.

[0022] According to some embodiments, the reference time point may be the start of a reference system frame, and the indication may include the sequence number of a system frame preceding the reference system frame.

[0023] According to a first aspect of the present invention, a method is provided for updating a time counter of a user equipment in a wireless network, the wireless network including at least one base station and a plurality of user equipments, the method comprising performing the following steps at the user equipment:

[0024] Receive a reference frame for signaling a reference time point associated with a reference time in a reference system frame;

[0025] Determine the propagation delay with the base station;

[0026] The time counter is updated using the reference time and the determined propagation delay.

[0027] The propagation delay is determined relative to a reference time point of the reference system frame.

[0028] In this way, since the propagation delay estimate is closer in time to the reference time point and reference frame, the estimated propagation delay is as close as possible to the actual propagation delay between the UE and gNB when the reference time point occurs.

[0029] Therefore, updating the time counter using the determined propagation delay is more accurate, and the compensation for the error in the propagation delay relative to the reference frame is then improved.

[0030] Optional features of the invention are defined in the appended claims. Some of these features will be described below with reference to methods, and these features can be converted into system features specifically for user equipment using the wireless network according to the invention.

[0031] According to some embodiments, determining the propagation delay may further include:

[0032] The transmission of the first measurement frame is scheduled relative to the reference time point.

[0033] According to some embodiments, the first measurement frame may be scheduled to be transmitted during a reference system frame, preferably during a reference system subframe including the reference time point, or during a reference system subframe preceding the reference subframe including the reference time point.

[0034] According to some embodiments, the first measurement frame may be scheduled to be transmitted during a predetermined system frame before, preferably immediately preceding, the reference system frame.

[0035] According to some embodiments, determining the propagation delay may further include:

[0036] The time for initiating the propagation delay determination is determined based on the system frame number of the current system frame, the current value of the time counter, and the system frame number of the reference system frame.

[0037] According to some embodiments, the determination of the propagation delay may further include:

[0038] Set the decrement timer to the determined start time; and

[0039] The determination of the propagation delay is initiated when the decrementing timer expires.

[0040] According to some embodiments, determining the propagation delay may include: retrieving a transmission time set for transmitting the first measurement frame from messages received from the base station.

[0041] And wherein, determining the propagation delay may include: receiving from the base station a timing advance command including information related to the propagation delay estimated by the base station.

[0042] According to some embodiments, determining the propagation delay with respect to the base station may include:

[0043] Transmit the first measurement frame to the base station;

[0044] Store the transmission time of the first measurement frame;

[0045] Receive a second measurement frame from the base station;

[0046] Store the reception time of the second measurement frame.

[0047] According to some embodiments, the second measurement frame may be transmitted during a reference system frame. Preferably, the second measurement frame may be a reference frame that signals the reference time point.

[0048] According to some embodiments, the second measurement frame may be transmitted during a system frame immediately following the reference system frame.

[0049] According to some embodiments, the method may further include: at the user equipment,

[0050] Receive at least one parameter from the base station for determining the propagation delay with the base station.

[0051] According to some embodiments, the at least one parameter may include at least one of the following: the time when the first measurement frame arrives at the base station, the time when the base station transmits the second measurement frame, and the difference between the arrival time of the first measurement frame and the transmission time of the second measurement frame.

[0052] According to some embodiments, at least one parameter can be received within the second measurement frame.

[0053] According to some embodiments, at least one parameter can be received in a system frame immediately following the reference system frame, in a message other than the second measurement frame.

[0054] According to some embodiments, the time when the first measurement frame arrives at the base station can be received within the second measurement frame, and the time when the base station transmits the second measurement frame can be received in an additional message following the second measurement frame.

[0055] According to some embodiments, the propagation delay can be determined using the transmission time of the stored first measurement frame, the reception time of the stored second measurement frame, and at least one parameter for determining the propagation delay.

[0056] According to another aspect of the present invention, a method is provided for updating a time counter of user equipment in a wireless network, the wireless network including at least one base station and a plurality of user equipment, the method comprising performing the following steps at the base station:

[0057] A reference frame is transmitted to signal a reference time point associated with a reference time in a reference system frame, in order to set the time counter of the user equipment;

[0058] Transmit measurement frames to the user equipment;

[0059] The transmission of the measurement frame is scheduled relative to the reference time point of the reference system frame.

[0060] According to another aspect of the present invention, a method is provided for updating a time counter of user equipment in a wireless network, the wireless network including at least one base station and a plurality of user equipment, the method comprising performing the following steps at the base station:

[0061] A reference frame is transmitted to signal a reference time point associated with a reference time in a reference system frame, in order to set the time counter of the user equipment;

[0062] The method further includes:

[0063] At least one resource within a system frame is selected relative to a reference time point of the reference system frame;

[0064] For the selected resource, select at least one resource allocation scheme, wherein the resource allocation scheme defines the allocation of each symbol of the selected resource for downlink transmission or uplink transmission or both.

[0065] Propagation delay is measured by exchanging at least one measurement frame using the selected resource.

[0066] This approach ensures that the propagation delay between the UE and gNB is determined as close as possible to the reference time point, thereby improving the accuracy of updating the UE's time counter. In practice, based on the selected resource allocation scheme provided by the gNB, the UE (and optionally the gNB) can schedule the transmission of the first measurement frame (and optionally the second measurement frame (in the case of the PTP method)) of either the PTP method or the TA mechanism to fall into resources with appropriate uplink (and optionally downlink) attributes.

[0067] Optional features of the invention are defined in the appended claims. Some of these features will be described below with reference to methods, and these features can be converted into system features specifically for a base station of a wireless network according to the invention.

[0068] According to some embodiments, the selected resource may be a time slot of a system frame, and the selection step may further include:

[0069] At least one time slot in the system frame is selected relative to a reference time point of the reference system frame;

[0070] For each selected time slot, a time slot allocation scheme is selected from the predefined time slot allocation schemes, where the time slot allocation schemes define the allocation of each symbol constituting the time slot for downlink transmission, uplink transmission, or both.

[0071] According to some embodiments, the selected resource may be included in the reference system frame or in a system frame adjacent to the reference system frame.

[0072] According to some embodiments, the selected resource may be adjacent to the reference time point.

[0073] According to some embodiments, the selected resource allocation scheme for the first selected resource may include at least one uplink symbol, and the first measurement frame may be received from the user equipment through the at least one uplink symbol.

[0074] According to some embodiments, the selected resource allocation scheme for the first selected resource may further include at least one downlink symbol, and a second measurement frame may be transmitted to the user equipment through the at least one downlink symbol.

[0075] According to some embodiments, the uplink symbol and the downlink symbol can be time-division duplex.

[0076] According to some embodiments, the uplink symbol and the downlink symbol may be frequency division duplex.

[0077] According to some embodiments, the selected resource allocation scheme for the second selected resource may include at least one downlink symbol, and at least one additional measurement frame may be transmitted to the user equipment via the at least one downlink symbol.

[0078] According to some embodiments, the additional at least one measurement frame may include a second measurement frame.

[0079] According to some embodiments, the additional at least one measurement frame may include a subsequent measurement frame for providing the user equipment with timing information of one or more exchanged measurement frames.

[0080] According to some embodiments, the first selected resource may be the last time slot of the reference system frame.

[0081] According to some embodiments, the second selected resource may be the start time slot of a system frame immediately following the reference system frame.

[0082] According to some embodiments, a resource allocation scheme that provides only uplink symbols consisting of multiple subcarriers can be used to select all time slots of a subframe in a system frame, and the first measurement frame can be received from the user equipment through the time slot of that subframe.

[0083] According to some embodiments, a resource allocation scheme that provides only downlink symbols consisting of multiple subcarriers can be used to select all time slots of another subframe in the system frame, and a second measurement frame can be transmitted to the user equipment through the time slots of that other subframe.

[0084] According to some embodiments, the subframe and the other subframe can be consecutive subframes in the same system frame.

[0085] According to some embodiments, the subframe and the other subframe may be the last two subframes of the same system frame.

[0086] According to some embodiments, the end of the same system frame may correspond to the reference time point.

[0087] According to another aspect of the present invention, a method is provided for updating a time counter of user equipment in a wireless network, the wireless network including at least one base station and a plurality of user equipment, the method comprising performing the following steps at the base station:

[0088] A reference frame is transmitted to signal a reference time point associated with a reference time in a reference system frame, in order to set the time counter of the user equipment;

[0089] Propagation delay is measured by exchanging at least one measurement frame using at least one resource exchange of system frames.

[0090] The reference time point is determined based on the resource allocation scheme of the at least one resource.

[0091] Accordingly, an apparatus is provided in a wireless network, the wireless network including at least one base station and a plurality of user equipment, the apparatus including a processor configured to perform the steps of the method described above.

[0092] The device has the same advantages as the method described above.

[0093] According to another aspect of the present invention, a computer-readable storage medium is provided that stores instructions of a computer program for implementing the above-described method when loaded into and executed by the programmable device.

[0094] According to another aspect of the present invention, a computer program is provided that, when executed, causes the above-described method to be performed.

[0095] At least a portion of the method according to the invention can be implemented by a computer. Therefore, the invention can take the form of a completely hardware embodiment, a completely software embodiment (including firmware, resident software, microcode, etc.), or an embodiment combining software and hardware aspects, all of which can be referred to herein as “circuit,” “module,” or “system.” Furthermore, the invention can take the form of a computer program product embodied in any tangible medium having computer-usable program code embodied therein.

[0096] Because this invention can be implemented in software, it can be embodied as computer-readable code for provision to a programmable device on any suitable carrier medium. Tangible, non-transitory carrier media may include storage media such as floppy disks, CD-ROMs, hard disk drives, magnetic tape devices, or solid-state storage devices. Transient carrier media may include signals such as electrical signals, electronic signals, optical signals, acoustic signals, magnetic signals, or electromagnetic signals (e.g., microwave or RF signals). Attached Figure Description

[0097] Embodiments of the invention will now be described by way of example only and with reference to the following figures, wherein:

[0098] Figure 1 An example of a 5G network that interconnects connected objects;

[0099] Figure 2 This is an example Figure 1 A diagram illustrating an example of the architecture of a 5G network base station;

[0100] Figure 3 This is an example Figure 1 A diagram illustrating an example of the architecture of user equipment in a 5G network;

[0101] Figure 4 Example of a system frame in a 5G network;

[0102] Figure 5 Examples of existing mechanisms for updating timers in user equipment;

[0103] Figure 6a and Figure 6b Illustrate the mechanisms of existing techniques used to estimate propagation delay between base stations and user equipment;

[0104] Figure 7a and Figure 7b This illustrates the general principle of the first aspect of the invention;

[0105] Figure 8 , Figure 8a and Figure 8b This example illustrates the method implemented at the base station, where Figure 8a and Figure 8b These correspond to the first and second embodiments of the first aspect of the present invention, respectively;

[0106] Figure 9 , Figure 9a and Figure 9b This example illustrates a method implemented at the user device, where... Figure 9a and Figure 9b These correspond to the first and second embodiments of the first aspect of the present invention, respectively;

[0107] Figure 10 and Figure 11 Examples of alternatives to the first embodiment of the first aspect of the present invention are shown;

[0108] Figure 12 A second embodiment according to the first aspect of the present invention is illustrated;

[0109] Figure 13 Example of resource allocation in time-division duplex (TDD) according to the second aspect of the invention;

[0110] Figure 14 Example of resource allocation in frequency division duplex (FDD) according to the second aspect of the present invention;

[0111] Figure 15Example of resource allocation for a reference signal consistent with a propagation delay measurement according to the first aspect of the invention; and

[0112] Figure 16 , Figure 17 , Figure 18 Four embodiments of resource allocation methods performed at gNB are illustrated. Detailed Implementation

[0113] The lists and names of elements (such as data elements) provided in the following description are illustrative only. Examples are not limited to these, and other names may be used.

[0114] The embodiments of the present invention are intended to be in Figure 1 The example shown is implemented in a 5G network used to interconnect connected objects or terminals.

[0115] The 5G network 100 includes multiple user equipment (UE) 104a, 104b, also referred to as mobile stations, that are wirelessly connected (indicated by dashed lines) to at least one base station 102 (gNB or gNodeB). The gNB 102 is connected to the core network 101, for example, via a wired (e.g., fiber optic) or wireless connection.

[0116] In this 5G network, the public time reference is provided by the Grand Master clock (5G GM) 103, as defined in TS23.501, Clause 5.27.

[0117] The 5G GM clock can be connected to core network 101, such as Figure 1 As shown, it can also be directly connected to either the gNB or the UE. Therefore, devices connected to the 5G GM clock share the common time reference provided by the 5G GM clock with other devices in the network.

[0118] According to some embodiments, the common time reference provided by the 5G GM clock can be a generic time reference or based on a generic time reference. For example, the generic time reference can be obtained directly from the satellite system by the gNB.

[0119] As described above, the 5G network 100 can be used to connect terminal devices 105a, 105b, and 105c, such as devices connected to an IoT network. The terminal devices can be, for example, example devices used in industrial equipment, such as sensors and actuators. Figure 1 As shown, terminal devices 105a, 105b, and 105c are connected to UEs 104a and 104b or network core 101 of the 5G network 100. According to some embodiments, terminal devices 105a, 105b, and 105c are wired to UEs 104a and 104b or network core 101.

[0120] According to some embodiments, a terminal device and a UE can be integrated into a single device.

[0121] Therefore, terminal devices 105a, 105b and 105c use the 5G network to share data.

[0122] When implementing time-sensitive applications in IoT networks, accurate time synchronization between UEs is mandatory, especially in 5G networks.

[0123] Figure 2 The diagram illustrates an example and a simplified internal architecture of the gNB 102.

[0124] The gNB 200 includes a 5G NR interface 205 that allows it to communicate with UEs 104a and 104b of the 5G network 100. The gNB may also include several different types of radio interfaces, such as LTE (4G) or other types of radio interfaces.

[0125] In order to communicate with the core network 101, the gNB also includes a core network interface 204, as defined in TS 23.501, Clause 4.2.

[0126] The synchronization of the gNB and the 5G GM clock is handled by the 5G time synchronization manager 203.

[0127] According to some embodiments, the 5G time synchronization manager 203 implements a time counter incremented by a local clock oscillator. The 5G time synchronization manager 203 continuously evaluates the time difference between the time counter and the 5G GM clock. This evaluation can be performed using the IEEE 1588 Precision Time Synchronization Protocol, which is implemented by exchanging time synchronization packets with the 5G GM clock via the core network interface 204. Therefore, the evaluated difference allows the 5G time synchronization manager 203 to determine and adjust the value of its time counter.

[0128] According to some embodiments, the 5G time synchronization manager 203 continuously evaluates the clock difference between the time counter and the reference time received from a satellite system (such as GPS).

[0129] Therefore, the 5G time synchronization manager 203 provides the precise current time to the UE synchronization manager 201 based on its local time counter.

[0130] The UE synchronization manager 201 is configured to handle the synchronization between the base station of network 100 and UEs 104a and 104b, so that the time counters of all these devices are synchronized as accurately as possible.

[0131] To this end, the UE synchronization manager 201 can implement several mechanisms, as described below. Figure 5As described, the UE synchronization manager 201 is also configured to evaluate and record the propagation delay between the gNB and the individual UEs 104a and 104b for synchronization purposes.

[0132] The gNB also includes a control manager 202 that implements the gNB control protocols. The control protocols include at least the following protocols: RLC (Radio Link Control TS 38.322), PDCP (Packet Replication Control Protocol TS 38.323), RRC (Radio Resource Control TS 38.331), and NAS (Network Access Layer TS 24.501). The control manager 202 therefore handles the generation of protocol packets exchanged with the core network 101 and the UE via the core network interface 204 and the 5G NR interface 205, respectively.

[0133] With the help of graphs Figure 3 Examples and simplified internal architectures of UE 104a and 104b are shown in the text.

[0134] UE 300 includes a 5G NR interface 305, which allows UE 300 to communicate with gNB 200 and 102. UE 300 may include several different types of radio interfaces, such as LTE (4G) or other types of radio interfaces.

[0135] The synchronization between the UE and the 5G GM clock is handled by the 5G time synchronization manager 303.

[0136] According to some embodiments, the 5G time synchronization manager 303 implements a time counter incremented by a local clock oscillator. When a time counter correction is received from the gNB synchronization manager 301, the 5G time synchronization manager 303 can correct or change the time counter value.

[0137] In practice, the gNB synchronization manager 301 stores the parameters required for synchronization provided by the gNB 102 and determined by the UE synchronization manager 201 of the gNB 102. Furthermore, the gNB synchronization manager 301 is also configured to evaluate and record the propagation delay between the UE 300 and the gNB 102.

[0138] UE 300 also includes a control manager 302 that implements the gNB control protocols. The control protocols include at least the following protocols: RLC (Radio Link Control TS 38.322), PDCP (Packet Replication Control Protocol TS 38.323), RRC (Radio Resource Control TS 38.331), and NAS (Network Access Layer TS 24.501). The control manager 302 handles the generation of protocol packets exchanged with gNB200 and 102 via the 5G NR interface 305.

[0139] The organization of data exchange between the gNB's 5G NR interfaces 205 and 305 and the UE follows the system frame formats specified by the 3GPP NR PHY and MAC protocols as defined in TS 38.300, Clauses 5 and 6.

[0140] The system frames used for data exchange are organized in a timely manner and have, for example, [missing information]. Figure 4 The structure is shown. The gNB notifies (or provides) system frames periodically using appropriate signals, such as through SIB1 messages.

[0141] System frames follow each other in time, one after the other. Each system frame lasts for 10 ms. The start of each system frame can be announced periodically by the gNB by transmitting a cyclic code / prefix.

[0142] System frames can be numbered using a System Frame Number (SFN) (also known as the system frame index). For example... Figure 4 As depicted, the first system frame, numbered #0, is followed by system frames #1, #2, and #3. The system frame numbers can be incremented. In other words, the system frame number increments every 10ms, from 0 to 1023, and once 1023 is reached, the numbering starts from 0 again.

[0143] Therefore, the gNB uses the SFN to number system frames. The SFN is signaled to the UE using a System Frame Synchronization Signal or Synchronization Signal Block (SSB). The SSB consists of the Primary Synchronization Signal (PSS), Secondary Synchronization Signal (SSS), and Physical Broadcast Channel (PBCH), which the UE uses to obtain time and frequency synchronization with the cell (including the gNB and associated UEs) at the symbol and slot levels. These synchronization signals (PSS, SSS) sent by the gNB help the UE detect frame and subframe boundaries. The SFN is signaled using the six most significant bits of the so-called MIB (Master Information Block) field and the four least significant bits of the so-called PBCH field. The gNB periodically sends the SSB to the UE at predefined symbols during the system frame (predefined moments in predefined resources of one or more subframes).

[0144] Each system frame consists of 10 subframes, ranging from 0 to 9.

[0145] Each subframe includes a flexible number of time slots, for example, up to 64 time slots. Each time slot includes several Orthogonal Frequency Division Multiplexing (OFDM) symbols. Each time slot consists of up to 14 OFDM symbols. Symbols can be declared as uplink symbols (i.e., used by the UE for transmission), downlink symbols (i.e., used by the gNB for transmission), or flexible (i.e., either uplink or downlink). The resource allocation scheme providing the type declarations for each symbol is declared by the gNB, for example, in an SIB1 message. The ordering of uplink, downlink, and / or flexible symbols is defined within a time slot, subframe, or the entire system frame.

[0146] gNB can choose from several predefined time slot allocation schemes, as detailed in Table 11.1.1-1: Time Slot Formats for Normal Cyclic Prefixes in standard TS38.213.

[0147] A cyclic prefix can be transmitted periodically by the transmitter to prevent interference. The cyclic prefix can also indicate the start and / or end of each OFDM symbol.

[0148] Therefore, system frames serve as a common reference for both the UE and the gNB to organize frame switching. Consequently, system frames, particularly their SFNs, are used for the routine adjustment of the UE's time counter.

[0149] Figure 5 The example below illustrates the normal time counter adjustment of the UE.

[0150] Regular time counter adjustments rely on providing the UE with a reference time value (T). R This updates the UE's time counter. The reference time value corresponds to the time at the reference time point of the system frame used as a reference. This is referred to below as the reference system frame.

[0151] For example, when a specific reference time point occurs in a reference system frame (e.g., at the end of the reference system frame), the reference time corresponds to the projection time of the gNB's time counter. The specific reference time point is the exact time point that the UE uses to update its time counter. Depending on the implementation, the time counter can be updated at the reference time point, or a time offset can be determined at the reference time point and then used to update the time counter.

[0152] Therefore, after receiving a request from the UE to update its time counter using a reference time value, or spontaneously, the gNB selects a future reference system frame that includes the reference time point, at which the gNB will force the UE to update its time counter using the reference time value provided by the gNB.

[0153] The reference time point can be freely chosen by the gNB, for example, corresponding to the end or start boundary of the reference system frame. In a variant, the reference time point can correspond to any predefined cyclic code / prefix (one or more predefined symbols) or physical preamble or message (such as the reference frame or synchronization signal) transmitted by the gNB during the reference system frame, or be used to signal the start boundary of the next system frame.

[0154] According to some embodiments, a reference time point can be predetermined as the beginning or end of a reference system frame. In this particular case, the information related to the reference time point includes only information related to the reference system frame, such as the number of reference system frames (referenceSFN).

[0155] Therefore, the reference time value can correspond to the time at the expected start or end time of the reference system frame, which can be inferred directly from any reference frame sent by the gNB to announce the start of the reference system frame or the start of the next system frame, or from any reference frame sent by the gNB during the reference system frame.

[0156] For the sake of simplicity, it is assumed in the following text that the reference time point is the end of the reference system frame (identified by its system frame number, referenceSFN). Therefore, thereafter, the only information related to the reference time point is the referenceSFN number.

[0157] like Figure 5 As shown, this reference time is equal to the sum of the following:

[0158] - The current time of the gNB's time counter, which is continuously synchronized with the 5G GM clock by the synchronization manager 203; and

[0159] - Indicates the duration T of the delay (in time counters) that the gNB will wait before reaching the reference time point during the reference system frame (e.g., the end of the reference system frame).

[0160] According to some embodiments that correspond to the end boundary of the reference time point and the reference system frame, the reference time can be determined by the gNB as, for example, the sum of the following:

[0161] - The current time of the gNB's time counter, synchronized to the 5G Grand Master clock by the synchronization manager 203;

[0162] - The remaining time before the start of the next system frame. This remaining time can be obtained by setting an alarm counter to 10ms at the beginning of each system frame and then decrementing it, as a new system frame occurs every 10ms.

[0163] -10ms*(referenceSFN-nextSFN), where reference is the SFN of the specified reference system frame, and nextSFN is the SFN of the next system frame. Note that if the reference time is calculated immediately before the start of the reference system frame, referenceSFN can be nextSFN. In this case, the reference time is included in the reference system frame, and the SIB9 message can be used. Normally, referenceSFN refers to a future reference system frame, i.e., referenceSFN-nextSFN>0.

[0164] Then refer to time T R The reference system frame indication (e.g., reference SFN) is provided to the UE. These two elements can be sent together or separately.

[0165] According to some embodiments, the gNB preparation includes a reference time T. R The referenceTimeInfo IE is then encapsulated within a System Information (SI) or Radio Resource Control (RRC) message (such as SIB9 or DLInformationTransfer messages).

[0166] like Figure 5 As shown, the DLInformationTransfer message is transmitted before the reference system frame.

[0167] SIB9 messages are transmitted during the reference system frame. Therefore, the SIB9 message directly includes the reference time T regarding the reference time point included in the same reference system frame. R Therefore, the gNB did not transmit any other messages related to the reference system frame beforehand.

[0168] like Figure 5 As shown in the diagram, if the message is broadcast, the gNB will send the message to the requesting UE or several UEs.

[0169] In the case of transmitting the DLInformationTransfer message, later, when the gNB's time counter equals the reference time, the gNB sends a reference frame to signal the reference time point of the reference system frame.

[0170] Furthermore, typically, a reference frame can be a cyclic code or physical preamble that begins a reference system frame, a cyclic code or physical preamble that begins the next system frame (e.g., when the reference time point is the boundary between the reference system frame and the next system frame), or any message transmitted during the reference system frame (e.g., a synchronization signal).

[0171] Once the UE detects the reference time point of the reference system frame due to the reference SFN and the reference frame, the previously received reference time T R The UE (its managers 301 and 302) sets its time counter to the reference time (or retrieves the reference time from the SIB9 message).

[0172] In the specific case of SIB9, the reference time corresponds to the time at the end boundary of the reference system frame.

[0173] However, as Figure 5 As shown, there is a delay between the time the gNB transmits the reference frame and the time the UE receives the reference frame. This delay (also known as propagation delay) represents the time it takes for the radio signal to propagate between the UE and the gNB.

[0174] Therefore, the above synchronization mechanism relies on the following assumption: the propagation delay of the reference frame (which is used by the UE as a trigger to set the UE's local time counter using the reference time supplied by the gNB) is negligible.

[0175] It is understandable that when a UE uses the reference time provided by the gNB to set its time counter, a permanent synchronization error is introduced due to the propagation delay of gNB messages. This may be incompatible with some applications (e.g., time-sensitive applications), especially those requiring accurate timestamps of packet arrival or departure times. In fact, the permanent synchronization error due to propagation delay introduces errors into the timestamps of these packets, which may be incompatible with the requirements of time-sensitive applications.

[0176] To overcome this drawback, the advantages of a precise time protocol (IEEE 1588) suitable for 5G systems can be utilized, such as periodically measuring the propagation delay between user equipment and base station during location triangulation estimation.

[0177] The estimated propagation delay is then used to compensate for the identified error. For example, a time counter is set to T when the reference time point is detected. R At this time, the UE can add the last estimated propagation delay to the time counter.

[0178] exist Figure 6a The example below illustrates the Precision Time Protocol (PTP) suitable for 5G systems.

[0179] PTP relies on the exchange of uplink and downlink measurement frames between the UE and gNB to estimate round-trip time (RTT) by timestamping the transmission and reception times of both the gNB and UE. The UE and gNB record the reception and transmission times of the exchanged frames using time counters on both sides.

[0180] First, such as Figure 6a As shown, the UE transmits the first measurement frame, namely the uplink frame #i, and records the transmission time t1 of the frame #i in the UE's internal memory.

[0181] Next, upon receiving the first measurement frame #i, the gNB stores the reception time t3 in its internal memory.

[0182] Next, the gNB transmits a second measurement frame, namely downlink frame #j, to the UE and records the transmission time t2 of frame #j in its internal memory. According to some embodiments, the transmission of the second measurement frame #j can occur before the first measurement frame #i is received. According to some embodiments, the transmission order of measurement frames #i and #j can be reversed.

[0183] Upon receiving the second measurement frame #j, the UE stores the reception time t4 of the second measurement frame #j in the UE's internal memory.

[0184] Once these two measurement frames #i and #j have been received, the UE and gNB perform the following calculations respectively: UE Rx-Tx = t4-t1 and gNB Tx-Rx =t2-t3. The obtained UE value is t2-t3 when the measurement frames do not overlap. Rx-Tx and gNB Tx-Rx Similarly, there are signs (positive or negative).

[0185] Then, gNB provides the calculated value gNB to the UE using subsequent (or following) downlink frames. Tx-Rx This parameter allows the UE to determine the propagation delay between the UE and the gNB.

[0186] When the calculated value gNB is received Tx-Rx When the UE receives a subsequent downlink frame, it then uses the UE-specific... Rx-Tx Subtract gNB Tx-Rx Subtract to determine the propagation delay:

[0187] Assuming the uplink and downlink transmission propagation delays are the same, then propagation delay = RTT / 2 = (UE) Rx-Tx -gNB Tx-Rx ) / 2.

[0188] Then, the time counter is set to T the next time the next reference time point is detected. R In this case, the estimated propagation delay can be added to the UE time counter. In a variant, it can be used directly after estimation to correct the time counter given the estimated propagation delay used when setting the time counter at a reference time point.

[0189] Therefore, considering the calculated propagation delay to update the user equipment's time counter is an improvement to meet the stringent end-to-end timing accuracy requirements of time-sensitive applications. In practice, the calculated propagation delay is then used to compensate for the identified error, namely the propagation delay associated with the transmission of the reference system frame.

[0190] An alternative method for determining the propagation delay between the gNB and the UE, known as the Timing Advance (TA) mechanism, is used and is defined in the standard in TS 38.211, Clause 4.3. Figure 6b The example shown illustrates the use of the TA mechanism to determine propagation delay. This mechanism provides a timing value within the timing advance (TA) command for each user equipment, which takes into account the estimated propagation delay for the user equipment.

[0191] To this end, the base station schedules the transmission time of uplink frames for user equipment and regularly monitors the propagation delay of these scheduled uplink frames, as the base station knows the transmission time of the uplink frame and can detect its arrival time. To control UE uplink timing, the gNB sends a TA command to the UE in a control message. The TA command is specific to a given UE because it reflects the propagation delay of that particular UE.

[0192] Upon receiving an uplink frame, the base station can compare the estimated propagation delay with the previously estimated propagation delay to detect a significant increase in propagation delay compared to the previously estimated propagation delay.

[0193] When a significant increase is detected, the base station sends a subsequent TA command to the user equipment to provide updated parameters, such as... Figure 6b As shown.

[0194] The user equipment records the command parameters, calculates the updated propagation delay, and waits for the next reference system frame. Upon detecting the next reference time point, the user equipment determines the updated time counter based on the last calculated propagation delay; that is, it adds the calculated propagation delay to the time counter set to T. R A time counter.

[0195] The gNB provides TA commands to the UE via the 5G NR interface. For transmission, the TA commands are encapsulated in different types of Protocol Data Units (PDUs) of the following types (all of which are defined in TS 38.321):

[0196] - As defined in TS 38.321, Clauses 6.1.5 and 6.2.3. The RAR is a response frame used by the UE during the random access procedure to associate a random access preamble with the gNB. During the RA procedure, the UE triggers a propagation delay measurement by transmitting the random access preamble to the gNB.

[0197] - Absolute timing advance command MAC control element or timing advance command MAC control element as defined in TS 38.321, Clauses 6.1.3.4 and 6.1.4a.

[0198] The TA command provides at least two pieces of information: parameters used to determine the propagation delay (or its own propagation delay) associated with previously sent uplink frames.

[0199] Uplink frames can be of different types. In the case of a TA command in a random access response, the uplink frame is a specific frame from the random access procedure. Otherwise, the uplink frame can be, for example, the Physical Uplink Shared Channel (PUSCH), Physical Uplink Control Channel (PUCCH), or Sounding Reference Signal (SRS) as defined in TS 38.213.

[0200] Depending on the type of TA command, the provided parameters can have different properties. In the case of random access response and absolute timing advance commands, the absolute value of the TA parameter is provided. In the case of timing advance commands, only the correction of the previously provided TA is included in the TA command.

[0201] Therefore, according to some embodiments, the TA command may include the absolute value of TA in the TA command field, and the absolute value of TA is then used by the UE to determine time T according to the following formula. TA :

[0202] T TA =(N TA +N TA,offset )*T C ,in,

[0203] N TA =TA*16*64 / 2 μ And μ is the subcarrier spacing configuration, Δf = 2μ * 15kHz, as defined in TS 38.211, Clause 4.2, and Table 4.2-1.

[0204] N TA,offset It is used to calculate the fixed offset for timing advance.

[0205] T C It is the basic time unit of the new air interface as defined in TS 38.211, Clause 4.1.

[0206] According to other embodiments, the TA command may include a previously provided TA value (TA). previous Correction (called TA) correction In this case, it should be applied to the previous T. TA The adjustment equals (TA) correction –31)*16*64 / 2 μ .

[0207] Interestingly, it can be noted that member N TA This value N is proportional to the round-trip time between the gNB and the UE. Assuming the propagation delay is symmetric, then this value N... TA This can help determine the propagation delay. For example, the propagation delay between the UE and the gNB is equal to (N TA *Tc) / 2.

[0208] In this way, when a TA command is received, the UE can determine the propagation delay during the transmission of the TA command. This is achieved when using the reference time T sent by the gNB. R When adjusting the time counter with the reference frame as described above, the calculated propagation value can be used.

[0209] However, assuming, for example, that the UE is moving relative to the base station, the propagation delay calculated using the PTP or TA mechanism can be estimated by using the UE's location, which is different from the UE's location when the reference frame is transmitted (based on the setting of the reference time trigger counter).

[0210] For example, if the UE moves away from the gNB between the moment the propagation delay is estimated and the moment the reference frame notifying the reference time point is received, when the time counter is set to T... R In such cases, the estimated propagation delay value will be insufficient to compensate for the actual propagation delay.

[0211] When triangulation estimation is performed by PTP in a periodic manner triggered independently of the reference frame (or reference time point), PTP is not suitable for accurately estimating propagation delay when the UE is moving relative to the gNB.

[0212] Similarly, since the TA mechanism is triggered independently of the reference frame, it is also unsuitable for accurately estimating propagation delay when the UE is moving relative to the gNB.

[0213] Therefore, it is necessary to improve the correlation between the measurement of propagation delay and the reference frame used by the UE to synchronize its local time counter with the 5G system clock.

[0214] In a first aspect, the present invention therefore proposes to schedule the determination of the propagation delay at the UE relative to a reference time point of a reference system frame.

[0215] Therefore, the reference time point of the reference system frame is used to schedule or trigger the measurement of propagation delay (or RTT) in a manner that is as close as possible to the reference time point and thus as close as possible to the reference frame.

[0216] In this way, because the propagation delay estimate is scheduled closer to the reference time point in time, the estimated propagation delay at the reference time point is as close as possible to the actual propagation delay occurring between the UE and gNB.

[0217] Therefore, updating the time counter with the determined propagation delay is more accurate and reduces [the impact of propagation delay]. Figure 5 The error is shown. The propagation delay is determined using an improved PTP method or an improved TA mechanism.

[0218] This article presents, and from Figures 7a to 11 Several embodiments are illustrated.

[0219] Figure 7a The general principles of the present invention based on the improved PTP method are illustrated according to embodiments of the present invention. Figure 7a The illustration shows frames exchanged between a UE and a gNB according to an embodiment of the present invention. Figure 7b Another embodiment using the TA mechanism is illustrated, wherein uplink frames are scheduled as described below.

[0220] Because of this invention, the propagation delay is determined close to the reference time T used to update the time counter of the UE. R It occurs at the associated reference time point.

[0221] First, regarding Figure 5 The process described is similar; the gNB sends downlink frames to the UE (in...). Figure 7a and 7b Of these two), the downlink frame includes information about the reference time point at which the UE will update its time counter, specifically including the SFN of the reference system frame and the associated reference time T. R .

[0222] In this example, the reference time point is, for example, but not limited to, the end of the reference system frame.

[0223] Downlink frames can be of two different types: DLInformationTransfer messages or SIB9 messages. (Combined) Figure 11 and Figure 12 The descriptions of the two embodiments further specify the details of using these message types.

[0224] In addition to information related to the reference time point, both types of messages can include additional information.

[0225] Regardless of the type of downlink message, the reception of downlink messages by the UE will trigger the scheduling of propagation delay measurements.

[0226] To update the UE's time counter as accurately as possible, the UE schedules propagation delay measurements close in time to the reference frame signaled at the reference time point. Therefore, this scheduled propagation delay measurement provides a near estimate of the propagation delay used by the UE to detect the reference frame at the reference time point. In practice, this propagation delay is the reason why time counters set only to the reference time may become out of sync.

[0227] Therefore, the UE schedules the determination of propagation delay relative to a reference time point known from previously received downlink frames. In other words, the UE schedules the start of propagation delay measurement based on the current time and information contained in previously received downlink frames related to the reference system frame (i.e., the target frame used to update the time counter).

[0228] The scheduling of propagation delay measurement can include, as described above, regarding... Figure 6a or Figure 6b The description specifies the transmission times of the first and (optionally) second measurement frames. The first measurement frame can be the first measurement frame used in the PTP method or an uplink frame in the TA mechanism. For the TA mechanism, a second measurement frame is not required because the gNB uses only one uplink frame to determine the propagation delay.

[0229] Advantageously, the scheduling time for the transmission of the first measurement frame is determined based on the resource allocation scheme previously provided by the gNB. The determination of the resource allocation scheme is further explained with respect to a second aspect of the invention.

[0230] According to some embodiments, scheduling propagation delay measurements includes determining the time for initiating the propagation delay determination, such as the transmission time of the first measurement frame. This is, for example... Figure 7a The situation in the scene.

[0231] Therefore, the time used to initiate the propagation delay measurement is based on the SFN of the current system frame, the current value of the time counter, and the SFN of the reference system frame.

[0232] Therefore, according to some embodiments, the timer can generate a determined time for initiating the propagation delay (or RTT) when it counts down to zero or up to the threshold. The UE can determine the threshold to set the UE's timer using the difference between the SFN of the current system frame (when a DLinformation message is received) and the SFN of a reference system frame, and using the system frame periodicity (typically 10ms, as previously mentioned): Timer value (threshold) = Current time + Time to the next system frame + 10ms * (referenceSFN - SFN of the next system frame).

[0233] Therefore, according to some embodiments, once the threshold is determined, a decrementing timer is set to the determined threshold as the initialization time. Then, when the decrementing timer expires, the determination of the propagation delay is initiated.

[0234] According to some TA command-based embodiments, uplink frame scheduling can be provided by the gNB. In other words, the gNB can provide the UE with information related to the transmission time of the uplink frame (i.e., the first measurement frame). In this case, the UE simply sets its timer to elapse at the provided scheduling time. According to the invention, the scheduling time thus provided is close to a reference time point.

[0235] In the TA command-based mechanism, when determining the reference time, the gNB can allocate resources to the UE for transmitting uplink frames (i.e., the first measurement frame) relatively close to the reference time point. Therefore, the allocated resources are signaled within the resource allocation scheme sent by the gNB to the UE. Thus, the UE infers the transmission time of the first measurement frame from the resource allocation scheme by retrieving the uplink resources allocated to it for the uplink frame. Regarding the second aspect of the invention, particularly concerning... Figure 16 Step 1604 further explains the resource allocation scheme from gNB to UE.

[0236] When the timer expires, the UE transmits the first measurement frame (which is an uplink message) to the base station, such as in Figure 7a and Figure 7b This is visible in both cases. Furthermore, the UE stores the transmission time t1 of the first measurement frame. The transmission time is the value of a time counter when the UE transmits the first measurement frame.

[0237] In the example shown, the first measurement frame is scheduled to be transmitted during the reference system frame but before the reference time point. Of course, the first measurement frame can be transmitted in other system frames, such as in a system frame before the reference system frame, preferably immediately preceding it. Alternatively, the first measurement frame can be scheduled to be transmitted during a system frame after (immediately following or not immediately following) the reference system frame.

[0238] Next, the gNB receives the first measurement frame and stores the time t3 at which the gNB received the first measurement frame. The reception time is the value of the gNB's time counter when the first measurement frame is received by the gNB.

[0239] Then, the gNB transmits a reference frame during the reference system frame. The reference frame signals a reference time point. The reference frame can be a cyclic code / prefix, a physical preamble, or a synchronization signal that declares the start of the reference system frame (in this case, the reference time point is 10 ms later) or the start of a system frame immediately following the reference system frame (in this case, the reference time point is the start of that system frame). The reference frame can also be a message transmitted at the reference time point (e.g., the end of the reference system frame).

[0240] As shown in the figure, when the reference time point of the reference system frame is detected, the UE uses the reference time T provided by the gNB and associated with the reference system frame. R To update the UE's local time counter.

[0241] Next, the gNB transmits an optional second measurement frame to the UE and records the transmission time of the second measurement frame as t2.

[0242] According to some embodiments, and as Figure 7a As shown, a second measurement frame is transmitted during a system frame that follows (or does not follow) the reference system frame.

[0243] According to some embodiments, a second measurement frame is transmitted during a system frame immediately preceding the reference system frame. This advantageously allows delay propagation estimation to be completed before the reference time point.

[0244] According to some embodiments, a second measurement frame is scheduled to be transmitted during a reference system frame. In particular, the second measurement frame may be a reference frame that signals a reference time point to the UE.

[0245] According to some embodiments, the transmission time of the second measurement frame is scheduled relative to a reference time point. For example, the transmission time of the second measurement frame can be scheduled before or after the reference system frame. Similar to the scheduling of the transmission time of the first measurement frame, a timer can be used at the gNB to manage the transmission time of the second measurement frame. The timer threshold can be determined by the gNB using the SFN of the current system frame (when sending information related to the reference time point), the reference SFN, and the system frame periodicity (typically 10ms as previously described).

[0246] Therefore, in parallel with the declaration of the reference system frame and reference time point, the gNB also schedules the transmission of the second measurement frame and sets a timer accordingly. Thus, when the timer expires, the gNB sends the second measurement frame. Using a timer has the advantage of being a reliable solution if the gNB responds quickly to the reception of the first measurement frame to trigger the transmission of the second measurement frame.

[0247] When the UE receives the second measurement frame, the UE records the reception time of the second measurement frame as t4.

[0248] Then, RTT or propagation delay can be related to the above regarding Figure 6a or Figure 6b Determined in the same way as described.

[0249] The difference can be added in a subsequent message. TX-RX Transmitted to the UE at t3 and / or t2.

[0250] According to some embodiments, the gNB transmits the value t2 directly to the UE in the second measurement frame. For this purpose, since the transmission time t2 is scheduled relative to a reference time point, it can be known in advance, allowing t2 to be directly included in the second measurement frame. Alternatively, the gNB can support immediate timestamp insertion after the timestamp point. In this case, subsequent information is not required.

[0251] Then, assuming the propagation delay is the same for uplink and downlink transmissions, the UE calculates the propagation delay between the UE and gNB using the following calculation: RTT = UE Rx-Tx -gNB Tx-Rx Or delayed propagation = (UE) Rx-Tx -gNB Tx-Rx ) / 2.

[0252] In a TA-based mechanism, a second measurement frame is not transmitted. For example... Figure 7b As shown, the gNB provides the UE with a transmission time to schedule the transmission of uplink measurement frames based on the reference time provided by the gNB. Then, the gNB estimates the propagation delay based on the reception of the uplink measurement frame sent by the UE. Therefore, the gNB only uses subsequent messages (i.e., subsequent TA commands, etc.) to transmit information related to the estimated propagation delay value. Thus, the UE calculates the propagation delay based on the received information. According to some embodiments, the subsequent message is a general subsequent message that directly includes the estimated propagation delay value. Such a message enables a reduction in computation at the UE.

[0253] Next, the UE uses the calculated propagation delay value to update its local time counter. This allows compensation for errors introduced when the UE has previously updated (or set) its time counter based on a reference time associated with a reference system frame. To do this, the calculated propagation delay is added to the previously set time T. R A time counter.

[0254] exist Figure 7a In the example shown, the first measurement frame and the second measurement frame are sent before and after the reference system frame, respectively.

[0255] According to some embodiments, the transmission order of the first measurement frame and the second measurement frame can be reversed: in this case, the second measurement frame is scheduled relative to the reference time point.

[0256] According to some embodiments, both the first measurement frame and the second measurement frame are sent and received before or after the reference system frame.

[0257] Furthermore, according to some embodiments, a first measurement frame and / or a second measurement frame may be transmitted during a reference system frame.

[0258] To better understand, regarding Figure 8 , Figure 8a , Figure 8b , Figure 9 , Figure 9a and Figure 9b The methods performed on the gNB side and the UE side are described in further detail.

[0259] In the illustrated embodiment, the reference time point is the end of the reference system frame. Therefore, in this embodiment, the information related to the reference time point is the referenceSFN.

[0260] Figure 8 For example, at gNB, it is used with reference time T R The corresponding method for updating the UE's time counter, and Figure 8a and Figure 8b Alternative methods for compensating for propagation errors introduced during UE time counter updates are illustrated. These methods are performed by the UE synchronization manager module 201 of the gNB.

[0261] The method for updating the UE's time counter at the gNB includes a first step 801, the purpose of which is to schedule a reference system frame.

[0262] Next, in step 802, gNB calculates the reference time T. R , such as regarding Figure 5 The explanation given.

[0263] Next, in step 803, the gNB prepares a message to provide the UE with information related to the reference system frame. For example, the message includes, for instance, an information element containing the reference SFN.

[0264] According to the present invention, this message has two uses:

[0265] The purpose is to link the new reference time point with the associated reference time T. R The UE will be notified in advance.

[0266] - Trigger the scheduling of propagation delay measurement between gNB and UE, so that the UE schedules propagation delay measurement close to the reference time point.

[0267] This message can be a dedicated RRC message or a dedicated MA CE / SIB or DLinformationTransfer message.

[0268] Then, in step 804, the gNB sends a preparation message containing information related to the reference system frame to the UE. The message may also include the reference time T. R .

[0269] In step 805, the gNB uses its 5G NR interface 205 to send a reference frame to signal the reference time point of the reference system frame. This can be a cyclic code, a physical preamble, or a synchronization signal, thereby signaling the start of the reference system frame or the start of the immediately following system frame.

[0270] Figure 9 For example, the corresponding method for updating the UE's time counter using a reference time on the UE side, and Figure 9a and Figure 9b Alternative methods for compensating for propagation errors introduced during UE time counter updates are illustrated. These methods are performed by the UE's gNB synchronization manager module 301.

[0271] The method for updating the UE's time counter at the gNB includes first, in step 901, receiving via the UE's 5G NR interface 305 a reference time point (referenceSFN) and a time counter (T) sent by the gNB in ​​step 804. R The message contains relevant information.

[0272] Next, in step 902, the UE extracts information related to the reference time point to determine the propagation delay relative to the reference time point and the current time. Therefore, the UE can use, for example... Figure 7a and Figure 7b The reference SFN provided in the received message, as described in the document, is used to schedule the determination of the propagation delay.

[0273] Scheduling may include setting a timer to expire at, for example, the same time as the start of a reference system frame. Of course, the timer used to transmit the first measurement frame can be set to another time close to the reference time. Therefore, initialization is performed using the sum of the following:

[0274] - The current time of the UE's time counter;

[0275] - The remaining time before the start of the next system frame. Since a new system frame occurs every 10ms, the remaining time can be obtained by setting an alarm counter to 10ms at the beginning of each new system frame; and

[0276] -10ms*(targetSFN index - nextSFN index), where targetSFN is the SFN of the system frame when the propagation delay is determined to start, preferably the reference system frame, and nextSFN is the SFN of the system frame that follows the current system frame.

[0277] In the variant, scheduling may include setting a timer to expire before the reference system frame arrives. Therefore, initialization is performed using the sum of the following:

[0278] - The current time of the UE's time counter;

[0279] - Remaining time before the start of the next system frame;

[0280] -10ms * (targetSFN index - nextSFN index - 1); and

[0281] -targetSubframes×1ms, where targetSubframes is an identifier (from 0 to 9) of one of the ten subframes that form the previous system frame. Therefore, the first measurement frame will be transmitted during this subframe.

[0282] Next, in step 903, the UE retrieves the reference time T from the message received in step 901. R .

[0283] According to some embodiments, reference time T R The message sent in step 901 is sent simultaneously with the indication of the reference time point. In this case, the message sent in step 901 is, for example, a DLInformationTransfer message that includes an IE called referenceTimeInfo, which includes both the reference time and the indication of the reference time point (such as referenceSFN). This situation occurs in... Figure 10 Example in.

[0284] According to some embodiments, reference time T can be received during the reference system frame.R In this case, the message sent is, for example, a SIB9 message, such as... Figure 11 As shown.

[0285] Next, once a reference time point is detected (e.g., one of the boundaries of the reference system frame derived from the reference frame sent by the gNB in ​​step 805), the UE uses the reference time T. R To set the UE's time counter so that the UE's time counter is synchronized with the gNB's time counter. (See also: Regarding...) Figure 5 As explained, unfortunately, this process introduces errors due to the propagation delay of the reference frame that signals the reference time point to the UE.

[0286] UE side such as Figure 9a and Figure 9b The two propagation delay measurement methods shown are designed to determine the propagation delay value used to compensate for the identified error. This method is performed by the UE's gNB synchronization manager module 301.

[0287] Each alternative method corresponds to an alternative method used to determine propagation delay, either PTP-based or TA-based. Depending on the method chosen, the corresponding method can be compared with, for example... Figure 8 (on the gNB side) and Figure 9 The methods for updating the UE's time counter (as shown on the UE side) are used in combination.

[0288] First, in step 910, the UE is triggered to initiate a propagation delay measurement by the expiration of the timer set in step 902.

[0289] As part of the scheduling, the UE sends the first measurement frame to the gNB via the UE's 5G NR interface 305 in step 911 or 918. The transmission time t1 of the first measurement frame is stored (step 912).

[0290] In the PTP method, according to some embodiments, the first measurement frame may be a message dedicated to RTT measurement and may include an indication of the purpose of the RTT measurement.

[0291] In both methods, according to some embodiments, the first measurement frame can be any uplink message sent as close as possible to the reference time point (before, during, or after the reference system frame). In this case, the gNB can switch from step 804 to active measurement mode to process each received uplink for propagation delay measurement.

[0292] Return to gNB, Figure 8a and Figure 8b The two alternative methods shown correspond to respectively Figure 9a and Figure 9bAn alternative method. On the gNB side, in step 810, the gNB receives the first measurement frame through the gNB's 5G NR interface 205.

[0293] In step 811, the gNB then stores the reception time of the first measurement frame as t3.

[0294] In step 812, the gNB sends a second measurement frame. The sending of the second measurement frame can be scheduled relative to a reference time point or triggered by receiving the first measurement frame.

[0295] According to some embodiments, the second measurement frame may be a message dedicated to RTT measurement and may include an indication of the purpose of RTT measurement.

[0296] According to some embodiments, the second measurement frame can be any downlink message sent as close as possible to the reference time point (before, during, or after the reference system frame).

[0297] According to some embodiments, a second measurement frame may be sent during a reference system frame.

[0298] Next, in step 813, the gNB stores the transmission time t2 of the second measurement frame sent in step 812. As previously mentioned, the transmission time t2 can be, for example, a reference time point or the start of a reference system frame or the next system frame.

[0299] Returning to the UE, in step 913, the UE then receives the second measurement frame sent by the gNB in ​​step 812. In step 914, the UE stores the reception time t4 of the second measurement frame.

[0300] In the TA-based method, a second measurement frame is not required. Therefore, in step 815, the gNB stores the reception time of the first measurement frame. Thus, no corresponding processing steps are performed.

[0301] Returning to the gNB side, in step 814, the gNB sends a subsequent message to the UE containing information related to the reception time t3 of the first measurement frame and the transmission time t2 of the second measurement frame. This information can be the values ​​of times t3 and t2 in separate fields, or more efficiently, the time difference between t2 and t3. Tx-Rx .

[0302] According to some embodiments, the subsequent message contains only information related to the transmission time t2 of the second measurement frame. In this case, information related to the reception time t3 of the first measurement frame may, for example, be previously sent to the UE within the second measurement frame.

[0303] According to some embodiments, there is no subsequent message. In this case, the second measurement frame directly contains the reception time t3 of the first measurement frame and the transmission time t2 of the second measurement frame (or simply the difference gNB). Tx-Rx Information related to this.

[0304] In the TA-based method, the subsequent message sent in step 817 is merely a subsequent TA command, which includes information related to the propagation delay estimated by the gNB in ​​step 816 by comparing the reception time (from step 815) with the transmission time. For example, this information may include a delay propagation correction that adjusts for the current delay propagation known to both the UE and the gNB. According to some embodiments, the subsequent message may be a general subsequent message that directly includes the value of the estimated propagation delay.

[0305] Returning to the UE side, in step 915, the UE obtains from the gNB the reception time t3 of the first measurement frame and the transmission time t2 of the second measurement frame (or simply the difference between the gNB and the gNB) Tx-Rx Information related to this.

[0306] This information may be included in a subsequent message sent in step 814, or may be included in part or in whole in the second measurement frame.

[0307] Next, in step 916, as described above, the propagation delay is inferred.

[0308] In the TA-based method, the estimated propagation delay can be retrieved directly from the subsequent message (TA command) received in step 919 (step 920).

[0309] Therefore, in step 917 or 921, the calculated value of the propagation delay is then used to correct the UE's time counter (by adding the estimated propagation delay to the time counter) to compensate for the error caused by the propagation delay of the reference frame used to detect the reference time point.

[0310] Therefore, the accuracy of the time counter updates is improved by taking into account the propagation delay of the reference system frame.

[0311] According to some embodiments, steps 810 to 814 and 910 to 917 of the propagation delay measurement can be performed before or after the reference system frame. In other words, the propagation delay measurement can be scheduled such that the transmission and reception of these two measurement frames occur before or after the reference system frame. In this case, according to some embodiments, steps 904 and 917 can be performed simultaneously, such that the time counter is updated using the sum of the reference time and the measured propagation delay.

[0312] Figure 10 and Figure 11An alternative to a previously proposed method for improving the accuracy of updating the UE's local time counter is illustrated.

[0313] As mentioned earlier, when the UE receives a reference time T that is used to set the UE's local time counter... R When a message containing relevant information is sent, a propagation delay measurement is scheduled. This message may be of a different type.

[0314] Figure 10 Example messages are embodiments of DLInformationTransfer as defined in standard TS 38.331, item 5.7.1.

[0315] The DLInformationTransfer message may include at least information related to a reference time point, enabling the UE to determine when to set the UE's time counter to the reference time T. R Therefore, information related to the reference time point can be included in an information element (IE) called referenceTimeInfo within the DLInformationTransfer message.

[0316] According to some embodiments, this information may include a reference SFN. According to some embodiments, this information may be included in the reference time T that the UE will use. R Information related to the precise reference time point of the reference system frame (e.g., the beginning or end of the reference system frame) when updating the UE's time counter.

[0317] According to some embodiments, in an information element (IE) called referenceTimeInfo, the DLInformationTransfer message may also include a reference time T. R Relevant information. As mentioned earlier, the reference time is used by the UE to update the UE's time counter. In this case, both the reference time and the reference time point are included in referenceTimeInfo.

[0318] According to some embodiments, within a frame other than the DLInformationTransfer message, the reference time T is transmitted separately from the reference time point (here, the referenceSFN value). R .

[0319] Figure 11 The following embodiment is exemplified, which includes a reference time T. R The relevant information message is a new type defined for the purposes of this invention, hereinafter referred to as an RTT measurement trigger frame (RTT measurementTF).

[0320] The gNB sends an RTT measurement trigger frame to trigger the scheduling of propagation delay measurements relative to a reference time point provided in the RTT measurement trigger frame. Therefore, the reference time point is then provided within the RTT measurement TF, i.e., the UE sets its local time counter to T. R In that instant.

[0321] Information related to the reference time point may include the referenceSFN value.

[0322] In the TA-based approach, RTTmeasurementTF can directly include the time when the UE sends the first measurement frame.

[0323] Similar to the previously proposed embodiments, measurement frames are then scheduled and sent close to the reference system frame and reference time point in time.

[0324] For example, using SIB9 messages to transmit the reference time T associated with the reference time point provided by the RTT measurementTF during the reference system frame. R In the specific case of SIB9, the provided reference time T R This corresponds to the end boundary of the reference system frame.

[0325] Therefore, when receiving a reference time T R When the SIB9 message is received, the UE sets the UE's time counter with reference time at the end of the reference system frame.

[0326] In both embodiments, the reception of the DLInformationTransfer or SIB9 message triggers the scheduling of propagation delay measurements near the reference time point of the reference system frame. Therefore, measurement frames #i and #j are then sent near the reference time point, ensuring that the determined propagation delay more accurately reflects the propagation delay of the reference frame signaled at the reference time point.

[0327] Therefore, the proposed method discloses a new use for DLInformationTransfer or SIB9 messages to improve the accuracy of UE time counter updates.

[0328] As in Figures 7a to 11 As described in detail, in a first aspect of the invention, the first measurement frame and the second measurement frame, as well as subsequent messages, are scheduled to be close in time to a reference time point, and therefore close to a reference frame affected by propagation delay error.

[0329] exist Figure 12The figure provides a better illustration of the timing of the measurement frame and subsequent messages. It shows the decision (1200) by which the gNB triggers a new reference time point (1205), including the reference time T. R Preparation of relevant information messages (1201) and their transmission (1202).

[0330] Here, the reference time point is chosen as the end of reference system frame #3. As mentioned earlier, the message used to measure the propagation delay between the UE and gNB is time-approaching with the signal notification and time reference T. R Reference frame 1205, associated with the reference time point, is sent.

[0331] At reference time 1205, the UE uses the reference time value T previously provided by the gNB in ​​message 1202. R Update the UE's time counter.

[0332] like Figure 12 As shown, a first measurement frame 1203 and a second measurement frame 1204 are transmitted during reference system frame #3. During system frame #4 immediately following reference system frame #3, a subsequent message 1206 is transmitted from the gNB to the UE, including the arrival time of the first measurement frame and / or the transmission time of the second measurement frame (or the difference between them). Of course, this scenario is merely an example scenario as described above.

[0333] In the TA-based method, only one measurement frame, uplink frame 1203, is transmitted, so that only uplink resources close to the reference time point are needed to estimate the propagation delay. The uplink frame can be, for example, but not limited to, uplink signals such as the Physical Uplink Shared Channel (PUSCH), Physical Uplink Control Channel (PUCCH), or Sounding Reference Signal (SRS) as defined in TS 38.213. Furthermore, in the method for providing the UE with information related to the propagation delay, a TA command is transmitted. The TA command requires downlink resources.

[0334] Both methods rely on message exchange between the gNB and the UE.

[0335] The resource allocation for transmitting these messages, the first measurement frame and an optional second measurement frame, and subsequent messages (for PTP-based or TA-based methods) are handled by the gNB. Through resource allocation, one should understand the determination of the opportunity to transmit uplink or downlink frames within a system frame. Depending on this, the gNB can declare more or fewer opportunities for transmitting uplink frames.

[0336] Such as about Figure 4As described, the system frame is subdivided in the time and / or frequency domains such that each symbol has a minimum duration set at a given frequency used for transmitting data. Before the reference system frame begins, the gNB can determine, based on a resource allocation scheme, which resources (time slots and / or OFDMA symbols) will be allocated to uplink or downlink transmissions within the system frame and their ordering.

[0337] By efficiently selecting an appropriate resource allocation scheme, the gNB can ensure that these messages are sent close in time to a reference time point, and thus close to the reference frame that signals the reference time point. In other words, it can ensure that the opportunity to send the first measurement frame (uplink frame) and the optional second measurement frame (downlink frame) is close to the reference time point.

[0338] Therefore, it is necessary to ensure that the propagation delay measurement initiated by the UE is consistent and compatible with the resource allocation scheme selected by the gNB.

[0339] Therefore, according to a second aspect of the invention, in order to transmit and / or receive information to determine the propagation delay with the UE, the gNB selects at least one resource in the system frame relative to a reference time point of the reference system frame, and selects a suitable resource allocation scheme for each selected resource. The gNB then performs the propagation delay measurement by exchanging at least one measurement frame in one or more of the selected resources. Figure 12 As shown, the gNB can provide uplink and downlink symbols in reference system frame #3, while the downlink symbols should be provided in subsequent system frame #4 (for subsequent frames).

[0340] Figure 16 A first embodiment of the method according to a second aspect of the present invention is illustrated, wherein the resource allocation scheme is determined by gNB based on a reference time T. R (And therefore the reference time point) is determined.

[0341] First, in step 1601, the gNB determines the synchronization requirements related to the UE in the 5G network. The accuracy of the propagation delay can vary depending on the UE's synchronization requirements. The gNB can determine these requirements upon receiving information from the UE (e.g., in RRC messages defined in TS 38.331, particularly in UEAssistanceInformation messages). The gNB can also infer these requirements based on QoS-related information such as Sensitive Communications (TSC) assistance information.

[0342] Next, in step 1602, as regarding Figure 7a or Figure 7b As explained, the gNB determines the time reference T to provide to the UE for updating the UE's time counter. RAnd the associated reference time point (e.g., via reference SFN value). As mentioned earlier, these two pieces of information can be provided to the UE together or separately.

[0343] Despite Figure 16 Not illustrated in the diagram, but recall that this information is transmitted to the UE, and then the gNB transmits a reference frame to signal the reference time T. R The associated reference time point. This allows the UE to set its time counter to T. R .

[0344] In step 1603, based on the reference time and the associated reference time point (i.e., the frame that signals the reference time point) and the synchronization requirements, the gNB selects at least one resource relative to the reference time point. The resource can be defined within one or more time slots, one or more subframes, or system frames close to the reference time point, in terms of time and / or frequency. The selected resource is used to transmit and receive measurement frames in a manner close to the reference time point to determine the propagation delay between the gNB and the UE.

[0345] Furthermore, in step 1603, the gNB then selects a resource allocation for the selected resource. The resource allocation can be time-based or frequency-based. The resource allocation defines the allocation of elements of the selected resource to uplink or downlink transmissions, or both. The elements of the resource can be of different types, such as symbols or carriers, time slots (if the selected resource is a subframe or system frame), or subframes (if the selected resource is a system frame).

[0346] Therefore, the gNB selects a resource allocation scheme that provides uplink and / or downlink elements of the selected resources for the transmission and reception of measurement frames that are compatible with the UE's synchronization requirements.

[0347] For example, using a PTP-based approach, gNB therefore selects the following resource allocation, where:

[0348] - Provide at least one uplink element close to the reference time point for the first measurement frame; and

[0349] - Provide at least two downlink elements close to the reference time point for the second measurement frame and subsequent messages.

[0350] For example, using a TA-based mechanism, the gNB thus selects a resource allocation scheme in which, regardless of whether certain elements are allocated as downlink resources, one or more uplink elements are provided for the transmission of at least one first measurement frame.

[0351] For example, a gNB selects a time slot as a resource, and therefore selects an associated time slot allocation scheme as the resource allocation scheme, such as... Figure 13 As shown.

[0352] The selection of these resources is designed to enable the exchange of measurement frames close to a reference time point to determine propagation delay. In some embodiments, multiple resources (e.g., time slots) are selected to transmit measurement frames.

[0353] To this end, the gNB first selects at least one resource relative to a reference time point. In practice, the gNB selects a resource close to the reference time point, during which measurement frames and subsequent messages can be transmitted.

[0354] Then, gNB selects a resource allocation scheme for the chosen resources.

[0355] For example, there are several predefined time slot allocation schemes, and these schemes are defined in standard TS 38.213, Table 11.1.1-1. In each predefined time slot allocation scheme, the ordering of uplink and / or downlink symbols within each time slot is provided (see reference examples of predefined time slot allocation schemes 0, 1, and 55 below). Figure 13 , Figure 14 ).

[0356] According to some embodiments, the selected resource allocation scheme may include at least one uplink symbol, preferably multiple uplink symbols, to provide uplink resources to the UE for transmitting the first measurement frame. Thus, such at least one uplink symbol can be used by the gNB to receive at least one measurement frame sent by the UE.

[0357] According to some embodiments, the selected resource allocation scheme may include at least one downlink symbol, preferably multiple downlink symbols, to allow the gNB to transmit a second and / or subsequent measurement frame. Thus, at least one such downlink symbol can be used by the gNB to transmit at least one measurement frame to the UE. Two different resources allocated to the downlink (possibly in different system frames) can be used to transmit the second measurement frame and subsequent messages, respectively.

[0358] In a TA-based mechanism, the selected resource allocation scheme may include at least one downlink symbol for sending subsequent TA commands (equivalent to subsequent measurement messages). Except where the TA command is of type MAC CE, the allocated downlink resources are TA-specific.

[0359] Therefore, the gNB selects a resource allocation scheme to provide uplink and downlink resources (e.g., symbols) for transmitting and receiving measurement frames compatible with the UE's synchronization requirements. The higher the UE's synchronization requirements, the closer the measurement frames should be to the reference time point.

[0360] Next, in step 1604, the gNB declares the selected resource allocation scheme by sending the selected resource allocation scheme to the UE.

[0361] Depending on the chosen method for determining propagation delay (TA-based or PTP-based), resource allocation can involve specific configurations.

[0362] For example, in a TA-based approach, the measurement frame can be a PUSCH and PUCCH signal. The gNB can reserve resources for the PUSCH channel dedicated to data that the UE wants to share with the gNB, or resources for the PUCCH channel dedicated to control frames (e.g., acknowledgment frames).

[0363] Then, the gNB can use the parameters defined in TS 38.331, namely PUSCH-config and PUCCH-config, to configure both the PUSCH and PUCCH channels. Additional configuration parameters exist for the PUCCH channels (referred to as the PUCCH resource set defined in La TS 38.213, Section 9.2.1), to refine the resource allocation of the PUCCH channels previously provided by the gNB.

[0364] Then, a declaration of the resource allocation scheme should be sent to the UE before the propagation delay measurement begins.

[0365] Resource configuration (i.e., resource allocation schemes for resource selection, such as time slots and symbols) can be provided to the UE in several ways.

[0366] For example, configuration can be provided to the UE using SIB1 messages, as defined in Section 6.2.2 of standard TS 38.331, which are periodically sent by the gNB (at least every 160ms). For example, SIB1 messages can be used.

[0367] Furthermore, configuration can be provided to the UE in the Physical Downlink Control Channel (PDCCH), which is included at the beginning of each downlink subframe (i.e., a subframe containing only downlink symbols). The PDCCH, which can be considered a control message, includes downlink control information (DCI) in various formats. Several DCI formats exist, as defined in standard TS 38.212, section 7.3, and one DCI format can also indicate the time slot allocation scheme for a subframe. For example, this is the case for DCI format DCI 2_0 defined in the standard TS 38.213, section 11.1.1. Some DCIs include frequency-domain resource allocation and time-domain resource allocation that allow for the definition of resource allocation in both time and frequency, such as DCI format 0, also known as UL-licensed.

[0368] Alternatively, configuration can be provided to the UE via the RRC message RRCreconfig, which includes an IE called ConfiguredGrantConfig for time and frequency allocation. Frequency allocation can also be defined in the FrequencyInfoUL and FrequencyInfoDL parameters (defined in TS 38.331).

[0369] In the TA command-based approach, the gNB can also use a declaration of the selected resource allocation scheme (i.e., sending the selected resource allocation scheme to the UE) to provide information related to the transmission time of the first measurement frame used by the UE during the delay propagation determination period. For example, the gNB allocates one or more uplink resources to the UE near a reference time point. Therefore, when the UE is about to send the first measurement frame, it originates from the allocated resources of the resource allocation scheme. The timing of transmission can be related to the beginning of a system frame, time slot, or symbol, which the UE may benefit from, for example, by... Figure 4 Synchronization signal.

[0370] To ensure accurate synchronization between the gNB and the UE, the gNB can send a reference time T to the UE, taking into account the update of the UE's time counter. R This method should be performed at that time.

[0371] Figure 17 A second embodiment of the method according to a second aspect of the invention is illustrated, wherein after obtaining the synchronization requirement (step 1701), in step 1702, the gNB first determines a resource allocation scheme. In step 1703, the gNB then approaches resources (e.g., time slots) with the possibility of providing uplink and downlink resources to schedule reference system frames (i.e., selecting a reference time point and associated reference time T). R Therefore, the gNB schedules the transmission of reference frames (and thus reference time points) so that the selected resource allocation scheme around the reference time points matches the resource requirements for exchanging measurement frames.

[0372] Figure 18 Examples and Figure 16 A third embodiment similar to the one described above, wherein, for example according to a PTP-based method or a gNB-based method, once the gNB selects a resource allocation scheme, the gNB sends a trigger frame to the UE to trigger the transmission of a first (uplink) measurement frame.

[0373] Steps 1801 to 1804 are the same as steps 1601 to 1604 previously described.

[0374] In addition to these steps, the gNB requests the UE to send an uplink measurement frame (i.e., the first measurement frame). Therefore, alternatively, the gNB can trigger a schedule for sending the first measurement frame relative to a reference time point provided to the UE as a reference system frame. This applies to both PTP-based and TA-based methods.

[0375] Upon receiving a gNB request, the UE can then schedule the transmission of a first measurement frame for determining the propagation delay.

[0376] According to some embodiments, the gNB trigger frame may be, for example, as described above. Figure 11 The described RTT measurement trigger frame.

[0377] According to some embodiments, in response to a gNB trigger frame, the UE can send a first measurement frame.

[0378] The gNB trigger frame should indicate the requested measurement frame (for propagation delay measurement) and the reference time T. R The link between (used for synchronization processing). In other words, the gNB trigger frame should emphasize the request for propagation delay measurement within the context of the synchronization processing of the gNB and UE time counters.

[0379] According to some embodiments, when transmitting to the UE, a new flag included in the IE ReferenceTimeInfo is used to send the request. Upon receiving ReferenceTimeInfo with this new flag set to true, the UE is forced to send a first measurement frame in the response.

[0380] Therefore, embodiments of the method according to the second aspect of the invention are carried out in parallel with the method according to the first aspect of the invention. Specifically, based on the selected resource allocation scheme provided by the gNB, the UE (and optionally the gNB) can schedule the transmission of a first measurement frame (and optionally a second measurement frame, in the case of the PTP method) or a TA mechanism to fall into resources with appropriate uplink (and optionally downlink) attributes.

[0381] Resource allocation can be done separately, such as Figure 13 and Figure 14 The time-division duplex or frequency-division duplex shown. If as... Figure 16 As shown, if the reference signal is used to calculate the propagation delay, then the resource allocation of the reference signal is also configured.

[0382] As an example, the UE can schedule the first measurement frame by selecting uplink symbols around a reference time point. This is possible because the gNB has already provided an appropriate resource allocation scheme for the time slot or resources.

[0383] According to some embodiments, the gNB can schedule the second measurement frame by selecting downlink symbols around a reference time point.

[0384] Therefore, as shown in these three embodiments, in order to ensure a correct estimate of the propagation delay taking into account the reference frame system, a second aspect of the invention proposes a method for updating the time counters of user equipment in a wireless network, which includes at least one base station and a plurality of user equipments. The method includes performing the following steps at the base station:

[0385] A reference frame is transmitted to signal the reference time point associated with the reference time in the reference system frame, thereby setting the time counter of the user equipment.

[0386] The method further includes:

[0387] Select at least one resource within a system frame relative to a reference time point of the reference system frame;

[0388] For the selected resource, at least one resource allocation scheme is selected, which defines how to allocate the symbols of the selected resource to downlink transmissions or uplink transmissions or both.

[0389] Propagation delay is measured by exchanging at least one measurement frame using the selected resource.

[0390] This method ensures that the propagation delay between the UE and gNB is determined as close as possible to the reference time point, thereby improving the accuracy of the UE's time counter updates.

[0391] Figure 13 , Figure 14 and Figure 15 An example scenario illustrating a time slot allocation scheme according to an embodiment of the present invention is provided.

[0392] Figure 13 , Figure 14 Examples of uplink and downlink resource allocation schemes according to the first and second embodiments of the present invention are provided, respectively, in time-division duplex mode and frequency-division duplex mode.

[0393] In the accompanying figures below, for ease of illustration, each of the two subframes (#9 and #0) comprises four time slots (considered as resources), with uplink symbols indicated in black, downlink symbols in gray, and flexible symbols (which can be used for either downlink or uplink) in white.

[0394] In this example, a reference time point is defined at the end boundary of reference system frame #3. Propagation delay measurements preferably occur close to this reference time point. This is why subframes #9 and #0 are two subframes surrounding the reference time point and are used for frame swapping.

[0395] In this way, gNB selects a time slot close to the reference time point.

[0396] like Figure 13 As shown, the time slots closest to the reference time point are specifically the last time slot 1301 of the last subframe #9 of reference system frame #3 and the first time slot 1302 of the subsequent subframe #0 of system reference #4. Figure 13 In the two examples shown, the gNB selects time slots 1301 and 1302 as resources, and therefore selects their time slot allocation scheme to ensure the transmission of the frames required to determine the propagation delay.

[0397] Therefore, two time slots adjacent to the reference time point are selected, and these two time slots are included in the reference system frame #3 and the system frame #4 immediately following the reference system frame, respectively.

[0398] According to some embodiments, the selected time slot may be included in the same system frame. For example, the selected time slot may be included in a reference system frame or in a system frame adjacent to the reference system frame.

[0399] In the first example (middle of the figure), two measurement frames (uplink and downlink) are sent in the same time slot 1301, before the reference time point, as follows. Figure 12 As shown. Therefore, in this example, the selected time slot allocation scheme for the last time slot 1301 of subframe #9 can be a predefined time slot allocation scheme 55 that alternates uplink and downlink symbols. Of course, other schemes that provide uplink and downlink symbols also exist.

[0400] Therefore, measurement frames 1303 and 1304 are sent using some uplink symbols (symbols 5, 6, and 7) and some downlink symbols (8, 9, and 10), respectively.

[0401] Still in this first example, the subsequent message is sent in the first time slot 1302 shortly after the reference time point. Therefore, in this example, the selected time slot allocation scheme for the first time slot 1302 of the first subframe #0 of system frame #4 following reference system frame #3 could be a predefined time slot allocation scheme 1 that only includes downlink symbols. Of course, other schemes that provide downlink symbols also exist.

[0402] Therefore, using some of these downlink symbols (e.g., symbols 5, 6, and 7) will include t2 and / or t3 or gNB. Tx-Rx The subsequent message 1306 was transmitted to the UE.

[0403] Therefore, considering propagation delay measurement, by selecting a time slot allocation scheme of time slots 1301 and 1302 adjacent to the reference time point, gNB enables propagation delay measurement in a manner close to the reference time point.

[0404] In the second example (bottom of the figure), the first measurement frame 1303 (uplink) is sent before the reference time point, and the second measurement frame 1304 (downlink) and subsequent message 1306 (downlink) (if present) are sent after the reference time point, as follows. Figure 7a and Figure 7b As shown.

[0405] Therefore, in this example, the selected time slot allocation scheme for the last time slot 1301 of subframe #9 could be a predefined time slot allocation scheme 0 that only includes uplink symbols. Of course, other schemes that provide uplink symbols also exist.

[0406] Therefore, the UE uses some uplink symbols (e.g., 0 to 3) in time slot 1301 to send the first measurement frame 1303.

[0407] Still in the second example, the second measurement frame 1304 and subsequent messages (if present) are sent shortly after the reference time point during time slot 1302. Therefore, in this example, the selected time slot allocation scheme for the first time slot 1302 of the first subframe #0 of system frame #4 following system frame #3 could be a predefined time slot allocation scheme 1 that only includes downlink symbols. Of course, other schemes that provide downlink symbols also exist.

[0408] Therefore, using some of these downlink symbols (e.g., symbols 0 to 4 and symbols 11 to 13 respectively) will include t2 and / or t3 or gNB. Tx-Rx The second measurement frame 1304 and subsequent message 1306 are sent to the UE.

[0409] In both examples, the number of symbols used for transmission can vary depending on the size of the messages (measurement frames and subsequent messages) and the subcarrier spacing used.

[0410] exist Figure 14 In, similar to Figure 13 The gNB selects the time slot closest to the reference time point to choose a suitable resource allocation scheme, thereby enabling the determination of propagation according to the first aspect of the invention. The closest resources are specifically the last time slot 1401 of the last subframe #9 of the reference system frame #3 and the first time slot 1402 of the subsequent subframe #0 of the subsequent system frame #4.

[0411] like Figure 14As shown, the proposed resource allocation is frequency division duplex, making it dependent on two frequencies, F1 and F2, as illustrated (more frequencies can be envisioned). In other words, during time slots 1401 and 1402, messages can be transmitted using symbols organized on two (or more) different frequencies (two different subcarriers). OFDM symbols can be used, as described above.

[0412] Therefore, with Figure 13 Unlike other time slots, time slots 1401 and 1402 include two frequencies.

[0413] The resource allocation scheme for slot 1401 is selected by the gNB, and includes:

[0414] -On the first frequency, only uplink symbols are used. Of course, other schemes that provide enough uplink symbols can be used.

[0415] -On the second frequency, only downlink symbols. Of course, other schemes that provide sufficient downlink symbols can be used.

[0416] In the example shown, the resource allocation scheme for slot 1402 is selected by the gNB such that only downlink symbols on the first and second frequencies are included. Of course, other schemes that provide sufficient downlink symbols can be used.

[0417] Therefore, the UE uses some uplink symbols on the first frequency of time slot 1401 to transmit the first measurement frame 1403. The gNB uses some downlink symbols on the second frequency of time slot 1401 (for the first measurement frame) and some downlink symbols on the second frequency of time slot 1402 (for subsequent messages) to transmit the second measurement frame 1404 and subsequent message 1406, respectively.

[0418] Therefore, the first measurement frame 1403 and the second measurement frame 1404 are sent in parallel at a time close to the reference time point.

[0419] Of course, this example is not limiting, and allows the use of any downlink symbol in slot 1401 on the second frequency and slot 1402 on both frequencies to transmit downlink frames, namely the second measurement frame and subsequent messages.

[0420] In addition, the allocation can be reversed, such that the first time slot 1401 includes only downlink symbols on both frequencies, and the second time slot 1402 includes only downlink symbols on the second frequency and uplink symbols on the first frequency.

[0421] The gNB then declares the selected resource allocation scheme to the UE, informing the UE which symbol / frequency carriers it can use to transmit data to or receive data from the gNB. The ordering of resource allocation, i.e., the configuration of uplink and downlink time slots, is provided to the UE by the gNB through several methods described above.

[0422] Figure 13 , Figure 14 and Figure 15 The example (if only SRS is used) also applies to TA-based methods where no second measurement frame is sent.

[0423] Figure 15 A third embodiment of resource allocation is illustrated, wherein the Position Reference Signal (PRS) and Sounding Reference Signal (SRS) as defined in TS 38.215, Section 5.1.30, which are typically used in positioning frames, are used as measurement frames according to the first aspect of the invention.

[0424] PRS and SRS signals are used to calculate the time difference for the UE. Rx-Tx and gNB Tx-Rx Dedicated signals, such as those related to Figure 7a and Figure 7b As described, the time difference UE Rx-Tx and gNB Tx-Rx Used to determine propagation delay.

[0425] To ensure that the PRS and SRS signals are transmitted close to the reference time point, in this example, the last two subframes of reference system frame #3, namely subframe #8 and subframe #9, include symbols reserved by gNB for downlink transmission of PRS and uplink transmission of SRS, respectively.

[0426] Subframe #8 is selected, and its resource allocation scheme provides only downlink symbols consisting of multiple subcarriers. The gNB transmits the PRS, which is considered the second measurement frame, to the UE in the time slot (and symbol) of the selected subframe #8.

[0427] Similarly, subframe #9 is selected, and its resource allocation scheme provides only uplink symbols consisting of multiple subcarriers. The SRS, considered the first measurement frame, is received from the UE in the time slot of subframe #9.

[0428] In this example, subframes #8 and #9 are the same system frame, preferably the last subframe of the reference system frame. Selected subframes can be included in two consecutive system frames.

[0429] The configuration for transmitting in Mode 1 and Mode 2, i.e., SRS and PRS, can vary. The gNB should ensure that the mode remains compatible with the format of the symbols used for transmission (i.e., the resource allocation scheme).

[0430] Using this configuration, the first and second measurement frames are sent close to the reference time point.

[0431] The configurations of the reference signals PRS and SRS are defined in sections 7.4.1.7 and 6.4.1.4 of standard TS 38.211, respectively.

[0432] The configuration of PRS and SRS allows the gNB to specify the resources allocated for the transmission of these reference signals. This configuration also allows specifying the periodicity characterizing the transmission pattern.

[0433] SRS and PRS configurations can also allow non-periodic configurations that can be triggered by DCIs, which include SRS requests and / or PRS requests, respectively. For example, sending only one SRS message.

[0434] Figure 18 The gNB trigger frame of the third embodiment is compatible with the resource allocation scheme described above. Figure 13 and Figure 14 In one embodiment, a gNB trigger frame can be sent in the PDCCH of a system frame that includes the transmission of IE ReferenceTimeInfo, where IE ReferenceTimeInfo includes information related to both the reference time and the reference time point. Figure 15 In one embodiment, a gNB trigger frame can be sent in the PDCCH of the reference system frame using the SRS request field in the DCI.

[0435] A computer program product for a programmable device is also provided, the computer program product including a sequence of instructions that, when loaded into and executed by the programmable device, implement embodiments of the first and second aspects of the invention.

[0436] In addition, a non-transitory computer-readable storage medium is provided for storing instructions for a computer program for implementing embodiments of the first and second aspects of the present invention.

[0437] Any step of the algorithm of the first and second aspects of the present invention may be implemented in software by a set of instructions or programs executed by a programmable computing machine (such as a PC (“personal computer”), DSP (“digital signal processor”) or microcontroller, etc.); or in hardware by a machine or special-purpose component (such as an FPGA (“field-programmable gate array”) or ASIC (“application-specific integrated circuit”), etc.).

[0438] Although the first and second aspects of the present invention have been described above with reference to specific embodiments, the first and second aspects of the present invention are not limited to the specific embodiments, and modifications within the scope of the first and second aspects of the present invention will be apparent to those skilled in the art.

[0439] When referring to the foregoing illustrative embodiments, many further modifications and variations will arise for those skilled in the art. These embodiments are given by way of example only and are not intended to limit the scope of the first and second aspects of the invention, the scope of which is defined only by the appended claims. Specifically, different features from different embodiments may be interchanged where appropriate.

[0440] The various embodiments of the first and second aspects of the present invention described above can be implemented individually or as a combination of multiple embodiments. Furthermore, features from different embodiments can be combined when necessary, or where a combination of elements or features from various embodiments is advantageous in a single embodiment.

[0441] In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite articles "a" or "an" do not exclude multiple elements. The mere fact that different features are stated in mutually different dependent claims does not indicate that combinations of these features cannot be used advantageously.

Claims

1. A method for synchronizing the time of a user equipment with the time of a base station in a wireless network, the method comprising performing the following steps at the user equipment: Receive information related to the reference time; Receive information related to time slot allocation, which is used to allocate individual symbols as downlink, uplink, or flexible, wherein the individual symbols are included in any time slot of a subframe in a system frame; The location reference signal (PRS) used to calculate the propagation delay is received based on the received information related to the time slot allocation. Based on the received information related to the time slot allocation, a probe reference signal, i.e., SRS, is transmitted to calculate the propagation delay; The propagation delay to the base station is calculated using the SRS and the PRS; and The time is synchronized using the reference time and the calculated propagation delay.

2. The method according to claim 1, wherein, Calculating the propagation delay further includes: The transmission of the SRS is scheduled relative to the reference time.

3. The method according to claim 2, wherein, The SRS is scheduled to be transmitted during a reference system frame that includes the reference time.

4. The method according to claim 3, wherein, The SRS is scheduled to be transmitted during a reference system subframe that includes the reference time, or during a reference system subframe preceding the reference subframe that includes the reference time.

5. The method according to claim 2, wherein, The SRS is scheduled to be transmitted during a predetermined system frame preceding the reference system frame that includes the reference time.

6. The method according to claim 5, wherein, The SRS is scheduled to be transmitted during a predetermined system frame immediately preceding the reference system frame.

7. The method according to claim 1, wherein, Calculating the propagation delay further includes: The time for initiating the calculation of the propagation delay is determined based on the system frame number of the current system frame, the current value of the user equipment's time, and the system frame number of the reference system frame that includes the reference time.

8. The method according to claim 7, wherein, Determining the time used to initiate the calculation of the propagation delay also includes: Set the decrement timer to the determined start time; and The calculation of the propagation delay is initiated when the decrementing timer expires.

9. The method according to claim 7, wherein, Determining the time used to initiate the calculation of the propagation delay includes: retrieving the transmission time set for transmitting the SRS from messages received from the base station. And wherein the calculation of the propagation delay includes: receiving a timing advance command from the base station, which includes information related to the propagation delay estimated by the base station.

10. The method according to claim 1, wherein, The calculation of the propagation delay to the base station includes: Store the transmission time of the SRS; and Store the reception time of the PRS.

11. The method according to claim 1 or 2, further comprising: At the user equipment, Receive at least one parameter from the base station for calculating the propagation delay to the base station.

12. The method according to claim 1, wherein, Information related to the time slot allocation is included in at least one of the following: one or more SIB1 messages, DCI messages, and RRCreconfig messages.

13. A method for synchronizing the time of a user equipment with the time of a base station in a wireless network, the method comprising performing the following steps at the base station: Transmit information related to a reference time to synchronize the time of the user equipment using the calculated propagation delay. in, The method further includes: Transmit information related to time slot allocation, which is used to assign individual symbols as downlink, uplink, or flexible, wherein the individual symbols are included in any time slot of a subframe within a system frame; Based on the received information related to the time slot allocation, a position reference signal (PRS) for calculating the propagation delay is transmitted; and The detection reference signal (SRS) used to calculate the propagation delay is received based on the received information related to the time slot allocation.

14. The method according to claim 13, wherein, The method further includes: At least one time slot in the system frame is selected relative to the reference time; For each selected time slot, a time slot allocation scheme is selected from a predefined time slot allocation scheme, wherein the time slot allocation scheme defines the downlink transmission, uplink transmission, or flexible allocation of each symbol constituting the time slot.

15. The method according to claim 14, wherein, The selected at least one time slot is included in a reference system frame that includes the reference time or in a system frame adjacent to the reference system frame.

16. The method of claim 14, wherein, The selected at least one time slot is adjacent to the reference time.

17. The method of claim 14, wherein, The selected time slot allocation scheme for the first selected time slot of the at least one time slot includes at least one uplink time slot, and the first measurement frame is received from the user equipment through the at least one uplink time slot.

18. The method according to claim 17, wherein, The selected time slot allocation scheme for the first selected time slot for the at least one time slot also includes at least one downlink time slot, and transmits a second measurement frame to the user equipment through the at least one downlink time slot.

19. An apparatus in a wireless network, the wireless network including at least one base station and a plurality of user equipment, the apparatus including a processor configured to perform the steps of claim 1 or 13.

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