Propagation Delay Compensation

Abstract

A method (500) implemented by a UE. The method includes the UE receiving a configuration message comprising positioning reference signal (PRS) resource configuration information that defines a PRS resource configuration. The method also includes the UE receiving a trigger message transmitted by a base station, the trigger message comprising information for identifying a PRS resource configuration. After receiving the trigger message, the UE also receives a PRS transmitted by the base station according to the PRS resource configuration, where the PRS is a semi-persistently transmitted DL reference signal or aperiodically transmitted DL reference signal.

Description

[Technical field]

[0001] SUMMARY OF THE DISCLOSURE Embodiments relating to propagation delay correction are disclosed. [Background technology]

[0002] 1. Current Status of the 3rd Generation Partnership Project (3GPP) The 3GPP Release 17 (Rel-17) Radio Access Network (RAN) work item "Extended Industrial Internet of Things (IoT) and Ultra-Reliable Low Latency Communications (URLLC) Support for New Radio (NR)" has the following objectives related to propagation delay compensation: TIFF0007603805000001.tif28170

[0003] The following is agreed: TIFF0007603805000002.tif75170

[0004] The reference cell for reference time distribution is the primary cell (PCell). The reference time information sent on the radio resource control (RRC) contains a field that indicates the reference system frame number (SFN) that corresponds to the reference time information. It is possible to have non-aligned SFNs across carriers in a cell group, which requires a reference cell, and it is specified in RRC that "if the referenceTimeInfo field is received in the DLInformationTransfer message, this field indicates the SFN of the PCell." The PSCell is not included because the DLInformationTransfer is sent on SRB1 / 2 on the master cell group (MCG) and not on the secondary cell group (SCG). In addition, the system information block 9 (SIB9) is only broadcast on the PCell, and this constraint aligns the RRC dedicated broadcast messages for reference time distribution.

[0005] 2. Multi-RTT Positioning Method In a multi-RTT positioning method, the UE position is estimated based on measurements performed at both the UE and the transmitting and receiving points (TRPs) (e.g., antenna panels--base stations (e.g., an NR base station (gNB) has one or more TRPs). The measurements performed at the UE and TRPs are UE / gNB Rx-Tx time difference measurements of DL-PRS and UL-SRS (and optionally downlink (DL) positioning reference signal (PRS) reference signal received power (DL-PRS-RSRP), and uplink (UL) positioning reference signal (SRS) RSRP (UL-SRS-RSRP)), which are used by the location management function (LMF) to determine the RTT. The following is an example of an NR base station (gNB) measurement for positioning:

[0006] The reporting range for gNB Rx-Tx time difference is -985024T as specified in TS 38.215, clause 5.2.3. c From +985024×T c The reporting resolution is uniform over the reporting range, T = T c *2 k where k is selected by the gNB from the set {0, 1, 2, 3, 4, 5}.

[0007] The LMF provides a recommended k value (k1). The gNB selects the parameter k (k2) and informs the LMF.

[0008] The mapping of measurements for each reporting resolution (k) is specified in Tables 13.2.1-1 to 13.2.1-6 of 3GPP TS 38.133 V16.4.0, shown below. TIFF0007603805000003.tif63170TIFF0007603805000004.tif64170TIFF0007603805000005.tif64170 TIFF0007603805000006.tif64170TIFF0007603805000007.tif64170TIFF0007603805000008.tif64170

[0009] 3. Reporting Mapping The UL SRS RSRP reporting range is specified from -156 dBm to -31 dBm with 1 dB resolution as specified in 38.215 clause 5.2.5. The mapping of the measurement quantities is specified in TS 38.133 table 13.3.1-1 (shown below). The signaling range may be larger than the guaranteed accuracy range. TIFF0007603805000009.tif158170 Summary of the Invention

[0010] Currently, there are some challenges: for example, the principle of the propagation delay correction method is the same as Timing Advance (TA) for uplink timing alignment and Round Trip Time (RTT) for positioning, but the reference signals to support legacy TA (with insufficient accuracy) and legacy RTT for positioning (with special functions to support positioning, e.g., interaction with a positioning server and multiple gNBs) are not suitable for propagation delay correction.

[0011] Thus, in one aspect, a method implemented by a UE is provided. The method includes the UE receiving a configuration message comprising positioning reference signal (PRS) resource configuration information that defines a PRS resource configuration. The method also includes the UE receiving a trigger message sent by a base station, the trigger message comprising information for identifying a PRS resource configuration. The method also includes, after receiving the trigger message, the UE receiving a PRS sent by the base station according to the PRS resource configuration, where the PRS is a semi-persistently transmitted DL reference signal or aperiodically transmitted DL reference signal.

[0012] In another aspect, a method implemented by a UE is provided. The method includes the UE receiving a configuration message comprising tracking reference signal (TRS) resource configuration information that defines a TRS resource configuration. The method also includes the UE receiving a trigger message transmitted by a base station, the trigger message comprising information for identifying a TRS resource configuration. The method also includes, after receiving the trigger message, the UE receiving a TRS burst transmitted by the base station according to the TRS resource configuration, where in the time domain, the TRS burst exists among at least three different symbols of a first slot and / or in the frequency domain, the TRS burst has a density of at least four for at least the first slot.

[0013] In another aspect, a computer program is provided comprising instructions that, when executed by processing circuitry of the UE, cause the UE to perform the UE method described above. In one embodiment, a carrier is provided containing the computer program, wherein the carrier is one of an electronic signal, an optical signal, a radio signal, and a computer readable storage medium.

[0014] In another aspect, a UE configured to perform the above-described method is provided. The UE may include a memory and a processing circuit coupled to the memory.

[0015] In another aspect, a method implemented by a base station is provided. The method includes transmitting a configuration message to the UE comprising PRS resource configuration information defining a PRS resource configuration. The method also includes transmitting a trigger message to the UE, the trigger message comprising information for identifying the PRS resource configuration. The method also includes transmitting a PRS according to the PRS resource configuration after transmitting the trigger message, where the PRS is a semi-persistently transmitted DL reference signal or aperiodically transmitted DL reference signal.

[0016] In another aspect, a method implemented by a base station is provided. The method includes transmitting a configuration message to the UE comprising TRS resource configuration information defining a TRS resource configuration. The method also includes transmitting a trigger message to the UE, the trigger message comprising information for identifying the TRS resource configuration. The method also includes, after transmitting the trigger message, transmitting a TRS burst according to the TRS resource configuration, where in the time domain, the TRS burst exists among at least three different symbols of a first slot and / or in the frequency domain, the TRS burst has a density of at least four for at least the first slot.

[0017] In another aspect, a computer program is provided comprising instructions that, when executed by a processing circuit of a base station, cause the base station to perform the base station method described above. In one embodiment, a carrier is provided containing the computer program, wherein the carrier is one of an electronic signal, an optical signal, a radio signal, and a computer readable storage medium.

[0018] In another aspect, a base station configured to implement the above-described method is provided. The base station may include a memory and a processing circuit coupled to the memory.

[0019] An advantage of the embodiments disclosed herein is that they allow the propagation delay between the UE and the base station to be accurately estimated using multiple sources of downlink reference signals (e.g., PRS, TRS) and more radio resources for each type of reference signal. In addition, the signaling overhead for transmitting these reference signals is limited by introducing explicit network triggering for these reference signals.

[0020] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate various embodiments. [Brief description of the drawings]

[0021] [Figure 1] FIG. 13 is a message flow diagram illustrating a process for determining RTT. [Diagram 2] FIG. 1 illustrates an example of an extended TRS, according to an embodiment. [Diagram 3] FIG. 1 illustrates an example of an extended TRS, according to another embodiment. [Figure 4] FIG. 13 is a message flow diagram illustrating a process for determining RTT. [Diagram 5] 1 is a flowchart illustrating a process according to some embodiments. [Figure 6] 1 is a flowchart illustrating a process according to some embodiments. [Figure 7] 1 is a flowchart illustrating a process according to some embodiments. [Figure 8] 1 is a flowchart illustrating a process according to some embodiments. [Figure 9] FIG. 1 illustrates a gNB according to some embodiments. [Figure 10] FIG. 1 illustrates a UE in accordance with some embodiments. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] The legacy multi-RTT positioning method utilizes UE Rx-Tx time difference measurements and downlink (DL) positioning reference signal (PRS) reference signal received power (RSRP) of downlink signals received from multiple TRPs measured by the UE, as well as measured gNB Rx-Tx time difference measurements and UL-SRS-RSRP at multiple TRPs of uplink signals transmitted from the UE. The measurements are used to determine the RTT at the positioning server, which is used to estimate the location of the UE.

[0023] RTT-based delay compensation is utilized on the legacy multi-RTT positioning method illustrated in FIG. 1. As illustrated in FIG. 1, a user equipment (UE) 102 (which may be any device capable of wirelessly communicating with a base station) transmits an uplink frame i and records the transmission time as t1. A base station (gNB) 104 receives the uplink frame i and records the arrival time of the first detected path as t3. The gNB then transmits a downlink frame j to the UE and records the transmission time as t2. The UE then receives the downlink frame j and records the arrival time of the first detected path as t4. The following calculations are performed: i) UE Rx-Tx diff=t 4- t1, and ii) gNB Rx-Tx diff=t 3- t2 is implemented in the UE and the gNB, respectively. This amount can be positive or negative depending on whether the gNB transmits the DL frame before receiving the UL frame or after receiving the UL frame. The propagation delay is given by RTT=gNB Rx-Tx diff+UE Rx-Tx It can be calculated like diff.

[0024] 1. Downlink reference signal for time-synchronized UE measurements: Positioning Reference Signal (PRS) 1.1.PRS Settings The positioning reference signal (PRS) from the gNB is used for time-synchronized UE measurements. As a result, the following set of RRC parameters are configured and sent from the gNB to the UE, instead of from the location server (specified in TS 37.355, LPP, v16.1.0) to the UE:

[0025] In one example, the configuration is per serving cell and unique for each UE. The IE nr-DL-PRS-InfoPerTRP is added to the IE ServingCellConfig (details shown below). The IE ServingCellConfig is used in the IE CellGroupConfig, which is sent in the RRC message RRCReconfiguration. A portion of the ServingCellConfig IE is shown below, illustrating that the ServingCellConfig IE may contain multiple nr-DL-PRS-InfoPerTRP IEs. TIFF0007603805000010.tif34170

[0026] In another example, the configuration is common for all UEs in one cell. This may be useful if all UEs in a cell require reference time distribution and the time is broadcast in SIB9 (System Information 9). In this case, the IE nr-DL-PRS-InfoPerTRP-AddModList is added to the ServingCellConfigCommon IE, a part of which is shown below: TIFF0007603805000011.tif28170

[0027] In LPP, one location server is connected to multiple gNBs and the UE measures multiple DL PRS from different gNBs. The UE measurement reports are sent on higher layers using the LPP protocol (in other words, the messages are transparent to the gNB). It is necessary to add a global PRS configuration ID in one location server for each UE. In this way, the location server can link the measurement reports to the gNB (or cell) and the associated PRS configuration.

[0028] In the LPP, the information element (IE) DL-PRS-ID-Info (shown in the table below) provides the ID of the DL-PRS resource of the referenced TRP. TIFF0007603805000012.tif41170

[0029] On the other hand, this global ID is not required when reporting in the UL to the gNB about the PRS configuration for time-synchronized UE measurements. The UE needs to report the measurement report with the IE ServCellIndex, configured with the IE ServingCellConfig in either the IE SpCellConfig or the IE SCellConfig. In other words, the above DL-PRS-ID-Info in the LPP protocol is not required on the RRC.

[0030] In one example, the PRS may only be present in the SpCell (PCell in MCG or PSCell in SCG) since the time in the reference time delivery message refers to the SFN in the PCell (if sent on MCG) or in the PSCell (if sent on SCG). In that case, the IE NR-DL-PRS-InfoPerTRP may be added to the SpCellConfig IE as shown below. TIFF0007603805000013.tif45170

[0031] The IE nr-DL-PRS-InfoPerTRP (shown in the table below) specifies the downlink PRS configuration per TRP, where the TRP is a component of the base station. For factory automation where the reference time is distributed, a cell can be served by multiple TRPs so that diversity gains are achieved to meet ultra-high reliability and low latency requirements. Each TRP can be at a separate coordinate, which makes it necessary to configure the PRS per TRP. TIFF0007603805000014.tif255170TIFF0007603805000015.tif255170TIFF0007603805000016.tif117170

[0032] The following are the RRC parameters already in 38.331 for measurements with measurement gaps: TIFF0007603805000017.tif124170

[0033] The following are the RRC parameters that need to be introduced into 38.331 to provide PRS configuration: TIFF0007603805000018.tif28170

[0034] 1.2 Time domain design of PRS Currently, the PRS is transmitted periodically for positioning purposes. For time synchronization purposes, the PRS can additionally be configured as a semi-persistently transmitted DL reference signal, or an aperiodically transmitted DL reference signal. The intention is that the PRS is sent only when it is needed for time synchronization, and is otherwise not present in order to save DL resources and reduce interference.

[0035] The RRC configuration of the PRS resource types is shown below. TIFF0007603805000019.tif15170

[0036] When the PRS resource type is aperiodic, the periodicity and resource set slot offset parameters are not applicable, which is reflected in the condition "Cond PeriodicOrSemiPersistent" shown below. TIFF0007603805000020.tif24170

[0037] This conditional presence indicates that if the resource type is "periodic" or "semi-persistent", then dl-PRS-Periodicity-and-ResourceSetSlotOffset is present. Otherwise, the field is not present.

[0038] Semi-persistent PRS is configured using the RRC protocol and activated / deactivated by a Medium Access Control (MAC) Control Element (CE) sent by the gNB. The MAC CE may indicate the serving cell ID, the TRP-ID (a unique identification of DL-PRS resources between the UE and the LMF) in the serving cell, and the NR-DL-PRS-ResourceSetID in the TRP. The serving cell ID is needed because the TRP-ID is only unique in one cell. The same applies to the NR-DL-PRSResrouceSetID for two different TRPs. In addition to the bit to indicate the PRS configuration, one additional bit is used to indicate whether it is activated (e.g., "1") or deactivated (e.g., "0").

[0039] In another approach, a cross-MAC entity unique resource set ID may be defined. This set ID is unique for each DL-PRSResourceSet defined in different TRPs of different serving cells. This approach may save signaling overhead when not all serving cells have the maximum allowed number of configured TRPs. This approach also allows simultaneous activation / deactivation of different PRSs in one MAC CE. This approach also allows activation of one configuration while deactivation of another configuration. For example, if it is constrained that only eight such PRS configurations can be provided to a UE, the MAC CE in the second approach may have 8 bits (one octet). Each bit indicates whether it is activated (e.g., "1") or deactivated (e.g., "0").

[0040] Alternatively, after activation by the MAC CE, the DL PRS exists for the RRC configurable time period pointed to by durationForSemiPersistent. The field is mandatory present if the resource type is "semi-persistent". Otherwise, the field is not present. In one example, the configurable time period is specified as an integer number with a periodicity specified in dl-PRS-Periodicity-and-ResourceSetSlotOffset. In another example, the configurable time period is specified as an absolute time duration, such as 5ms, 10ms, 15ms, 20ms, etc.

[0041] The same principle of this method of introducing "durationForSemiPersistent" can be added for any DL reference signal for propagation delay estimation and correction, for example, "Downlink Reference Signal for Time Synchronous UE Measurements: TRS" described below.

[0042] The triggering mechanism for aperiodic PRS can be downlink control information (DCI). In one method, this DCI is also used to trigger the UE to report measurements in the UL at a future time. Between the reception time and this future time, the network transmits the PRS according to one of the configurations indexed by information in a field in the DCI.

[0043] 1.3 Frequency domain design of PRS In a preferred embodiment, measurement gaps are not needed for time synchronization purposes since the UE only needs to receive the PRS of the serving cell and not the PRS of neighboring cells. In this case, the UE is only required to measure DL PRS in the active bandwidth portion (BWP) that uses the same numerology as the active DL BWP.

[0044] In another embodiment, to prepare for handover, the UE needs to perform measurements of neighbor cell PRS. In this case, the serving cell obtains the target cell PRS information and transmits the PRS information to the UE. The UE then performs measurements of the neighbor cell PRS accordingly. Measurement gaps may be provided by the serving cell to match the neighbor cell PRS pattern so that DL signals in the serving cell do not interfere with the neighbor cell PRS and the UE can tune its radio to measure the PRS in the neighbor cell without listening to the transmission from the current serving cell.

[0045] 1.4 PRS sequence generation In general, a pseudorandom sequence generator is Initialized using TIFF0007603805000021.tif35170, Where: TIFF0007603805000022.tif10170 is the slot number and the downlink PRS sequence ID TIFF0007603805000023.tif10170 is given by the upper layer parameter dl-PRS-SequenceID, where l is the OFDM symbol in the slot to which the sequence is mapped. For time synchronization, the sequence ID is determined so that the DL PRS can be compatible with the CSI-RS. Limited to TIFF0007603805000024.tif10170.

[0046] 1.5 PRS Resource Settings For time synchronization, the UE only needs to be configured with the PRS of one TRP, preferably the TRP that serves as the UE's primary serving cell (in other words, the TRP in the PCell). The reason is that the reference cell for reference time distribution is the PCell. If only one TRP is enabled, nrMaxTrpPerCell in the RRC configuration example is set to 1.

[0047] Up to nrMaxSetsPerTrp (a constant defined in the RRC configuration example) resource sets may be configured for a given TRP. An example involves two resource sets for a given TRP.

[0048] Each resource set includes multiple resources. Each resource can correspond to a different beam in the spatial domain. A UE may be able to reliably detect only a subset of the beams (or resources) in a resource set. Different UEs may receive different beams, for example, depending on the location of each UE.

[0049] 1.6 PRS Muting PRS muting may be defined to control the interference of PRS in one cell towards neighboring cells. To achieve a reduction in mutual interference between neighboring cells, neighboring gNBs may coordinate with each other on PRS muting patterns. Coordination may be through the exchange of information elements over the Xn interface between gNBs in a distributed manner. Note that for time synchronization purposes, there is no entity such as a location server (which exists for positioning purposes but not for timing synchronization purposes) to act as a central coordinator for the gNBs.

[0050] In another example, in case of time synchronization integrated with Time Sensitive Networking (TSN) (see section 5.27.1 of TS 23.501 version 16.4.0), the NW-TT (Network Side Translator Function), which resides at the edge of the 5G system together with the User Plane Function (UPF), can take over the role of the location server. All gNBs send PRS muting patterns to the NW-TT. The NW-TT then forwards to one gNB the muting patterns of its neighboring gNBs. In another example, the NW-TT may allocate PRS muting patterns to different gNBs. This is useful when neighboring gNBs may not have an Xn interface between them. This approach also requires the gNBs to report neighboring gNBs to the NW-TT, which can be collected by listening to the system information of the neighboring gNBs.

[0051] 1.7 NR DL PRS Processing Capability for Time Synchronization DL PRS processing capabilities may be reported by the UE for time synchronization purposes. For example, the UE may report to the gNB, prior to the start of measurements for time synchronization, one or more of the following capabilities: 1) maximum number of frequency layers, 2) maximum number of TRPs per frequency layer, 3) maximum number of PRS resource sets per TRP per frequency layer, 4) maximum number of resources per PRS resource set (X4), 5) maximum number of DL PRS resources per UE, 6) maximum number of TRPs for all frequency layers per UE, 7) maximum number of resources per frequency layer, 8) whether the above has a difference in frequency range 1 or frequency range 2, or 9) whether the above has a difference in TDD or FDD.

[0052] 2. Downlink reference signal for time-synchronous UE measurements: TRS A Tracking RS (TRS) (also known as a "CSI-RS for tracking") may be used by a UE to obtain timing measurements. A TRS may be used alone or together with a compatible set of PRS.

[0053] In this case, for a UE configured to perform timing measurements for time synchronization purposes, a UE in RRC connected mode is expected to receive a higher layer UE specific configuration of NZP-CSI-RS-ResourceSet with the higher layer parameter trs-Info set to "true" (as shown in the table below). TIFF0007603805000025.tif71170

[0054] To improve the time synchronization accuracy, the existing TRS can be extended.

[0055] In one example, the periodicity and slot offset for periodic NZP CSI-RS resources are flexible and can be set according to the need for time synchronization. In Rel-15 / Rel-16, the periodicity is 2 μ X p slots, where X p = {10, 20, 40, or 80}, and μ can be {0, 1, 2, 3} according to the SCS, in other words, the periodicity is {10, 20, 40, or 80} ms. In NR, one slot is always 1 2 -μ In milliseconds. A more flexible periodicity setting may be provided to meet the needs of TSN clock synchronization. In the following, M is the maximum periodicity value, and M may be 80 as in Rel-15 / Rel-16, or M may be other values, e.g., M=120.

[0056] For example, allow any periodicity up to M (ms) that is a multiple of 10 slots. In that case, one option is to set the periodicity to 2 μ X p slot, where X p= {10, 20, 30, 40, 45, ..., or M}, where M is a multiple of 10.

[0057] For example, allow any periodicity that is a multiple of 5 slots up to M (ms). In that case, one option is to set the periodicity to 2 μ X p slot, where X p = {5, 10, 15, 20, 25, 30, 40, 45, ..., M-5, or M}, where M is a multiple of 5.

[0058] For example, we allow any periodicity that is a multiple of one slot, up to M (ms). In that case, one option is to allow the periodicity to be 2 μ X p slot, where X p = {1, 2, 3, ..., M-2, M-1, or M}, where M is an integer.

[0059] In one example, densities greater than ρ=3 are supported for the TRS. For example, ρ=3 (in other words, CSI-RS occupies 6 subcarriers in each RB) may be supported in addition. Alternatively, ρ=3 as illustrated in FIG. 3 may be achieved by two sets of NZP-CSI-RS, where both sets of NZP-CSI-RS are configured with the same l but with frequency Domain Allocations that have an offset from each other. For example, one NZP-CSI-RS has Blue REs and the other NZP-CSI-RS has Orange REs.

[0060] In one example, more symbols in a slot are supported. For example, there can be 2, 4, 6, or 8 CSI-RS resources in a slot. Correspondingly, 4, 8, 12, or 16 CSI-RS resources in two consecutive slots that are the same across two consecutive slots. The time domain location defined by the higher layer parameter CSI-RS-resourceMapping is given by one of the following:

[0061] For 4 CSI-RS resources in a slot, Two sets from {l∈{4, 8}, l∈{5, 9}), or l∈{6, 10}} for frequency range 1 and frequency range 2. For example, l∈{4, 5, 8, 9} or l∈{5, 6, 9, 10}; For frequency range 2 Two sets from TIFF0007603805000026.tif7170, e.g. l∈{0, 1, 4, 5} or l∈{2, 3, 6, 7}; Four CSI-RS resources in a slot may be achieved by the gNB configuring two sets of NZP-CSI-RS, where different "firstOFDMSymbolInTimeDomain" and "firstOFDMSymbolInTimeDomain2" are configured for the two sets of NZP-CSI-RS. As an example, in Figure 2, one NZP-CSI-RS has Blue REs and the other NZP-CSI-RS has Orange REs.

[0062] For 6 CSI-RS resources in a slot, 3 pairs of symbols, with 2 symbols in a pair separated by 4 symbols for both FR1 and FR2. For example, l ∈ {4, 5, 6, 8, 9, 10} or l ∈ {0, 1, 2, 4, 5, 6}; 6 CSI-RS resources in a slot can be achieved by the gNB configuring 3 sets of NZP-CSI-RS.

[0063] For 8 CSI-RS resources in a slot, 4 pairs of symbols, with 2 symbols in a pair separated by 4 symbols for both FR1 and FR2. For example, l ∈ {3, 4, 5, 6, 7, 8, 9, 10}; 8 CSI-RS resources in a slot can be achieved by the gNB configuring 4 sets of NZP-CSI-RS.

[0064] In one example, a TRS burst may consist of three or more slots, where a TRS burst is the number of slots that a TRS is assigned to during a TRS period. For example, in addition to bursts of one or two slots per periodicity, n consecutive slots per periodicity may be supported, where 2 μ X p >n>2.

[0065] In one example, a wider BW may be supported for the TRS. The increased BW may be for operation on either paired spectrum (i.e., FDD), unpaired spectrum (i.e., TDD), or shared spectrum channel access. For example, instead of limiting the TRS to 52 PRBs or less, the TRS bandwidth may be up to X max PRBs, where 2 >= X max >52. For example, the minimum bandwidth of TRS may be increased. The increase may be for both FR1 and FR2, or only for FR2, or both. For example, the minimum TRS for time synchronization is set to be X PRBs, where X≧32 resources if the UE points to trs-AddBW-Set1 for trs-AdditionalBandwidth capability, and X≧36 resources if the UE points to trs-AddBW-Set2 for AdditionalBandwidth capability.

[0066] FIG. 2 illustrates an example of an extended TRS over a period, where the TRS burst consists of two slots. The TRS exists in four symbols l∈{4, 5, 8, 9}, and the density in the frequency domain is ρ=3. The subcarrier offsets for l∈{4, 8} and for l∈{5, 9} are set to be separated by two subcarriers.

[0067] Figure 3 illustrates an example of an extended TRS over a period, where the TRS burst consists of one slot, the TRS is present in two symbols l ∈ {4, 8}, the density in the frequency domain is increased to ρ = 6, and 6 REs are evenly spaced across 12 subcarriers in the PRB.

[0068] For the tracking RS (aka "CSI-RS for tracking") used by the UE to obtain timing measurements, the legacy RRC configuration for CSI reporting can be reused. The CSI reporting is configured in the IE CSI-MeasConfig (shown below), which is sent in the IE ServingCellConfig of the RRC message RRCReconfiguration. TIFF0007603805000027.tif33170

[0069] The IE CSI-MeasConfig contains a CSI-ReportConfig IE (shown below) that links the resources identified by the ID CSI-ResourceConfigId and the report ID CSI-ReportConfigId, where the reporting indicates the type of reporting, such as periodic, semi-persistent or aperiodic. TIFF0007603805000028.tif92170

[0070] In that case, the resource configuration identified by the CSI-ResourceConfigId contains the configuration of the CSI-RS resources. This IE (CSI-ResourceConfig) also contains the reference signal resource type such as periodic, aperiodic, and the bwp ID. TIFF0007603805000029.tif82170

[0071] Multiple reference signals such as NZP CSI RS, CSI IM, SCI SSB may be used in the CSI-ResourceConfigId. If NZP-CSI-RS is used, the PHY layer details of the CSI-RS resources specified below, including power, scrambling ID, periodicity, etc. TIFF0007603805000030.tif62170

[0072] The resource mapping illustrated in Figures 2 and 3 is performed by the following IE CSI-RS-ResourceMapping. TIFF0007603805000031.tif109170

[0073] 3. Uplink Reference Signal for Time-Synchronized TRP Measurements The UL SRS for positioning design, including sequences, SRS resource types, comb designs, and symbol locations in slots, etc., can be largely reused for time synchronization purposes.

[0074] Meanwhile, some parameters may be set differently for time synchronization purposes compared to positioning. One reason is that the SRS for time synchronization only needs to be detected by the serving TRP, whereas for positioning purposes, the SRS needs to be detected by multiple TRPs.

[0075] For example, a new antenna port may be defined for sending UL SRS for time synchronization.

[0076] Also, collision handling of SRS for time synchronization may be handled differently than SRS for other purposes. For example, SRS for time synchronization may be assigned a higher priority than SRS for other purposes. If a collision occurs between different SRS types, the SRS for time synchronization is preserved and the other SRS types are dropped.

[0077] In addition, for time synchronization purposes, only the DL reference signal of the serving cell is used as the DL path loss reference for the purpose of SRS power control, e.g., the SSB of the neighbor cell does not need to be included in the SRS configuration (e.g., "SSB-InfoNcell") for time synchronization purposes.

[0078] If a TRS is used together with an SRS for time synchronization, the CSI-RS resource ID (in other words, "NZP-CSI-RS-ResourceId") of the TRS (aka "CSI-RS for tracking") may be used as a DL path loss reference signal to pair with the UL SRS. As an example, an RRC configuration is provided in the table below. TIFF0007603805000032.tif255170TIFF0007603805000033.tif192170

[0079] 4. Coupling of DL RS and UL RS For both the TA-based method and the RTT-based method, it is preferable that the same set of {downlink reference signals, uplink reference signals} is used in the timing calculation at the UE and the timing calculation at the gNB.

[0080] For example, the same pair of {DL PRS, UL SRS} is used by both the gNB and the UE at approximately the same time for time synchronization calculations.

[0081] In contrast, it is not preferable for (a) the gNB to use {DL PRS, UL PRACH} for uplink timing estimation while (b) the UE uses {DL TRS, UL SRS} for downlink timing estimation and then to perform time synchronization using (a) and (b).

[0082] Thereby, it is preferable for the gNB to use RRC configuration to group a set of {downlink reference signals, uplink reference signals} in one information element for time synchronization purposes.

[0083] In one example, a pointer to the uplink reference signal is added to a new IE NR-DL-PRS-ResourceSet as shown below. TIFF0007603805000034.tif74170

[0084] 4 is a message flow diagram illustrating a process according to an embodiment. In the embodiment shown, the process begins with the gNB 104 transmitting a configuration message 402 (e.g., an RRC reconfiguration message) comprising reference signal (RS) resource configuration information for RS resource configuration. For example, the RS resource configuration information may comprise or consist of PRS resource configuration information that specifies PRS resource configuration. As another example, the RS resource configuration information may comprise or consist of TRS resource configuration information that specifies TRS resource configuration.

[0085] After sending the configuration message 402, the gNB 104 sends a trigger message 404 to the UE, where the trigger message 404 comprises information for identifying an RS resource configuration. In some embodiments, the gNB 104 may also send a second trigger message 406 to the UE, where the trigger message 406 comprises information for identifying a second RS resource configuration for the UE 102 to use in transmitting an RS to the gNB 104.

[0086] After transmitting the trigger message 404, the gNB 104 transmits an RS 408 (e.g., an RS burst) according to the RS resource configuration identified by the trigger message 404. The gNB 104 also records the time when the gNB 104 transmitted the RS (this time is denoted as T1), and the UE 102 records the time when the UE 102 received the RS 408 (this time is denoted as T2). In some embodiments, the UE 102 transmits a signal 410 to the gNB 104. In this embodiment, the UE 102 records the time when the UE 102 transmitted the signal 410 (this time is denoted as T3), and the gNB 104 records the time when the gNB 104 received the signal 410 (this time is denoted as T4). The UE 102 then transmits the signal 410 to the UE 104. Rx-Tx Diff = T3-T2 is calculated, and gNB104 is gNB Rx-Tx Diff = T4 - T1. Then, the propagation delay is calculated as RTT = UE Rx-Tx diff+gNB Rx-Tx It can be calculated as diff.

[0087] 9 is a block diagram of a base station 104 according to some embodiments for implementing the base station methods disclosed herein. As shown in FIG. 9, the base station 104 includes a processing circuit (PC) 902 that may include one or more processors (P) 955 (e.g., one or more general-purpose microprocessors and / or one or more other processors, such as application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), etc.), which may be co-located in a single housing or in a single data center, or may be geographically distributed (in other words, the base station 104 may be a distributed computing device), and at least one network interface 968 to allow the base station 104 to communicate with the network 110 (e.g., the Internet) to which the network interface 968 is connected. The PC 902 may comprise at least one network interface 968 comprising a transmitter (Tx) 965 and a receiver (Rx) 967 for enabling the base station 104 to transmit data to and receive data from other nodes connected to the PC 902 (e.g., an Internet Protocol (IP) network), a communication circuit 948 coupled to an antenna configuration 949 comprising one or more antennas and comprising a transmitter (Tx) 945 and a receiver (Rx) 947 for enabling the base station 104 to transmit data and receive data (e.g., transmit / receive data wirelessly), and a local storage unit (a.k.a., a "data storage system") 908 which may include one or more non-volatile storage devices and / or one or more volatile storage devices. In embodiments in which the PC 902 comprises a programmable processor, a computer program product (CPP) 941 may be provided. The CPP 941 comprises a computer readable medium (CRM) 942 that stores a computer program (CP) 943 comprising computer readable instructions (CRI) 944. The CRM 942 may be a non-transitory computer-readable medium, such as a magnetic medium (eg, a hard disk), an optical medium, a memory device (eg, a random access memory, a flash memory), or the like.In some embodiments, the CRI 944 of the computer program 943 is configured such that when executed by the PC 902, the CRI causes the base station 104 to perform the steps described herein (e.g., steps described herein with reference to flow charts). In other embodiments, the base station 104 may be configured to perform the steps described herein without the need for code; that is, for example, the PC 902 may consist only of one or more ASICs. Thus, features of the embodiments described herein may be implemented in hardware and / or software.

[0088] Figure 10 is a block diagram of a UE 102 according to some embodiments. As shown in Figure 10, the UE 102 may include a processing circuit (PC) 1002, which may include one or more processors (P) 1055 (e.g., one or more general-purpose microprocessors and / or one or more other processors, such as an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), etc.), a communication circuit 1048, coupled to an antenna configuration 1049 with one or more antennas, and including a transmitter (Tx) 1045 and a receiver (Rx) 1047 for enabling the UE 102 to transmit data and receive data (e.g., transmit / receive data wirelessly), and a local storage unit (a.k.a., "data storage system") 1008, which may include one or more non-volatile storage devices and / or one or more volatile storage devices. In an embodiment in which the PC 1002 includes a programmable processor, a computer program product (CPP) 1041 may be provided. The CPP 1041 includes a computer readable medium (CRM) 1042 that stores a computer program (CP) 1043 comprising computer readable instructions (CRI) 1044. The CRM 1042 may be a non-transitory computer readable medium, such as a magnetic medium (e.g., a hard disk), an optical medium, a memory device (e.g., a random access memory, a flash memory), or the like. In some embodiments, the CRI 1044 of the computer program 1043 is configured such that, when executed by the PC 1002, the CRI causes the UE 102 to perform the steps described herein (e.g., steps described herein with reference to a flowchart). In other embodiments, the UE 102 may be configured to perform the steps described herein without the need for code. That is, for example, the PC 1002 may consist of only one or more ASICs. Thus, features of the embodiments described herein may be implemented in hardware and / or software.

[0089] Overview of Various Embodiments A method 500 (see FIG. 5) implemented by a UE (e.g., UE 102), the method comprising: the UE receiving a configuration message (e.g., an RRC reconfiguration message) comprising PRS resource configuration information defining a positioning reference signal (PRS) resource configuration (see step s502); the UE receiving a trigger message (e.g., a MAC CE or DCI) transmitted by a base station (e.g., base station 104) (see step s504), the trigger message comprising information for identifying a PRS resource configuration; and after receiving the trigger message, the UE receiving a PRS transmitted by the base station according to the PRS resource configuration (see step s506). In some embodiments, the PRS is a semi-persistently transmitted DL reference signal or aperiodically transmitted DL reference signal.

[0090] A2. The method of embodiment A1, further comprising: the UE recording a first time value (T1) indicating a time when the UE received the PRS; the UE transmitting a signal to the base station; the UE recording a second time value (T2) indicating a time when the UE transmitted the signal; and the UE calculating either T1-T2 or T2-T1.

[0091] A3. The method of embodiment A2, in which the UE sends a signal to the base station as a result of receiving the trigger message.

[0092] A4. The method of embodiment A3, in which the PRS configuration comprises a pointer to an uplink configuration, and the UE sends a signal to the base station according to the uplink configuration.

[0093] A5. The method of any one of claims A1 to A4, wherein the UE is configured with a PRS for only one transmission and reception point (TRP).

[0094] A6. The method of claim A5, wherein one TRP is in a primary serving cell of the UE.

[0095] B1. A method 600 (see FIG. 6) implemented by a UE (e.g., UE 102), the method including the UE receiving a configuration message (e.g., an RRC reconfiguration message) comprising tracking reference signal (TRS) resource configuration information that specifies a TRS resource configuration (see step s602), and the UE receiving a trigger message (e.g., a MAC receiving a TRS resource configuration (CE or DCI) from the base station after receiving the trigger message (see step s604), the trigger message comprising information for identifying a TRS resource configuration; and after receiving the trigger message, the UE receiving a TRS burst transmitted by the base station in accordance with the TRS resource configuration (see step s606), wherein, in the time domain, the TRS burst exists among at least three different symbols of the first slot and / or, in the frequency domain, the TRS burst has a density of at least four for at least the first slot (in other words, in a given symbol of the first slot, the TRS burst exists in at least four resource elements).

[0096] C1. A computer program 1043 comprising instructions 1044 that, when executed by a processing circuit 1002 of a UE (eg, 102), causes the UE to perform a method according to any one of the above embodiments.

[0097] C2. A carrier containing the computer program of embodiment C1, wherein the carrier is one of an electronic signal, an optical signal, a radio signal, and a computer-readable storage medium 1042.

[0098] D1. A UE (e.g., UE 102), wherein the UE is adapted to perform a method according to any one of embodiments A1 to A6 or B1.

[0099] D2. A UE (e.g., UE 102), the UE comprising a processing circuit 1002 and a memory 1042, the memory including instructions 1044 executable by the processing circuit, thereby enabling the UE to operate to perform a method according to any one of embodiments A1 to A6 or B1.

[0100] A method 700 (see FIG. 7) implemented by a base station (e.g., base station 104), the method comprising: transmitting a configuration message (e.g., an RRC reconfiguration message) to a UE (e.g., UE 102) comprising PRS resource configuration information defining a positioning reference signal (PRS) resource configuration (see step s702); transmitting a trigger message (e.g., a MAC CE or DCI) to the UE (see step s704), the trigger message comprising information for identifying a PRS resource configuration; and transmitting a PRS according to the PRS resource configuration after transmitting the trigger message (see step s706). In some embodiments, the PRS is a semi-persistently transmitted DL reference signal or aperiodically transmitted DL reference signal.

[0101] E2. The method of embodiment E1, further comprising: recording a first time value (T1) indicating a time when the base station transmitted the PRS; receiving a signal transmitted by the UE; recording a second time value (T2) indicating a time when the base station received the signal; and calculating either T1-T2 or T2-T1.

[0102] E3. The method of embodiment E2, in which the trigger message triggers the UE to transmit a signal.

[0103] E4. The method of embodiment E3, in which the PRS configuration comprises a pointer to an uplink configuration, and the UE is configured to transmit a signal to the base station according to the uplink configuration.

[0104] E5. The method of any one of claims E1 to E4, wherein the base station configures the UE with a PRS for only one transmit and receive point (TRP).

[0105] E6. The method of claim E5, wherein one TRP is in a primary serving cell of the UE.

[0106] F1. A method 800 (see FIG. 8) implemented by a base station (e.g., base station 104), the method comprising: transmitting a configuration message (e.g., an RRC reconfiguration message) to a UE (e.g., UE 102) comprising TRS resource configuration information that specifies a tracking reference signal (TRS) resource configuration (see step s802); transmitting a trigger message (e.g., a MAC CE or DCI) to the UE (see step s804), the trigger message comprising information for identifying a TRS resource configuration; and after transmitting the trigger message, transmitting a TRS burst according to the TRS resource configuration (see step s806), wherein in the time domain, the TRS burst exists among at least three different symbols of a first slot and / or in the frequency domain, the TRS burst has a density of at least four for at least the first slot (in other words, in a given symbol of the first slot, the TRS burst exists in at least four resource elements).

[0107] G1. A computer program 943 comprising instructions 944 that, when executed by a processing circuit 902 of a base station (e.g., base station 104), cause the base station to perform a method according to any one of embodiments E1 to E6 or F1.

[0108] G2. A carrier containing the computer program of embodiment G1, wherein the carrier is one of an electronic signal, an optical signal, a radio signal, and a computer-readable storage medium 942.

[0109] H1. A base station (eg, base station 104) adapted to implement the method of any one of embodiments E1 to E6 or F1.

[0110] H2. A base station (e.g., base station 104) comprising a processing circuit 902 and a memory 942, the memory including instructions 944 executable by the processing circuit, whereby the base station is operable to perform a method as described in any one of embodiments E1 to E6 or F1.

[0111] While various embodiments have been described herein, it should be understood that the embodiments have been presented by way of example only, and not by way of limitation. Thus, the breadth and scope of the present disclosure should not be limited by any of the exemplary embodiments described above. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the present disclosure, unless otherwise indicated herein or otherwise clearly contradicted by context.

[0112] Additionally, while the processes described above and illustrated in the figures are shown as a sequence of steps, this is done for illustrative purposes only, and it is therefore contemplated that some steps may be added, some steps may be omitted, the order of the steps may be rearranged, and some steps may be performed in parallel.

Claims

1. A method (500) performed by a user equipment (UE) (102), the method comprising: The UE receiving (s502) a configuration message comprising positioning reference signal (PRS) resource configuration information defining a PRS resource configuration; receiving (s504) a trigger message transmitted by a base station (104), the trigger message comprising information for identifying the PRS resource configuration; After receiving the trigger message, the UE receives (s506) a PRS transmitted by the base station according to the PRS resource configuration identified by the information for identifying the PRS resource configuration. Equipped with The PRS is a DL reference signal transmitted semi-persistently or a DL reference signal transmitted aperiodically. Method (500).

2. The method of claim 1 , wherein the information provided by the trigger message indicates whether to activate or deactivate the PRS resource configuration.

3. The method of claim 2 , wherein after the activation, the PRS is received for a configurable period of time.

4. The method according to claim 2 or 3, wherein the PRS resource configuration information is received by Radio Resource Control (RRC) signaling, and the trigger message is a MAC Control Element (CE).

5. The method of claim 4 , wherein the MAC CE indicates a serving cell ID, a TRP ID in the serving cell, and a PRS resource set ID in the TRP.

6. The method of claim 5 , wherein the MAC CE further comprises bit information indicating whether the PRS resource configuration should be activated or deactivated.

7. recording, by the UE, a first time value (T2) indicating a time at which the UE received the PRS; the UE transmitting an uplink reference signal to the base station; recording, by the UE, a second time value (T3) indicating a time at which the UE transmitted the uplink reference signal; the UE calculating either T2-T3 or T3-T2; The method of claim 1 , further comprising:

8. The method of claim 7 , wherein the UE transmits the uplink reference signal to the base station as a result of receiving the trigger message.

9. the PRS resource configuration comprises a pointer to an uplink configuration; the UE transmitting the uplink reference signal to the base station according to the uplink configuration; The method according to claim 8.

10. The method according to claim 1 , wherein the UE is configured with the PRS of only one transmission and reception point (TRP).

11. The method of claim 10, wherein the one TRP is in a primary serving cell of the UE.

12. A method (600) performed by a user equipment (UE) (102), the method comprising: The UE receives (s602) a configuration message comprising tracking reference signal (TRS) resource configuration information defining a TRS resource configuration; The UE receiving (s604) a trigger message transmitted by a base station (104), the trigger message comprising information for identifying the TRS resource configuration; After receiving the trigger message, the UE receives (s606) a TRS burst transmitted by the base station according to the TRS resource configuration identified by the information for identifying the TRS resource configuration; Equipped with In the time domain, the TRS bursts are present during at least three different symbols of a first slot; and / or In the frequency domain, the TRS burst has a density of at least 4 for at least the first slot. Method (600).

13. A computer program (1043) comprising instructions (1044) which, when executed by a processing circuit (1002) of a user equipment (UE) (102), cause the UE (102) to perform a method according to any one of claims 1 to 12.

14. A user equipment (UE) (102), comprising: Receiving (s502) a configuration message comprising positioning reference signal (PRS) resource configuration information defining a PRS resource configuration; Receiving (s504) a trigger message transmitted by a base station (104), the trigger message comprising information for identifying the PRS resource configuration; receiving (s506) a PRS transmitted by the base station according to the PRS resource configuration identified by the information for identifying the PRS resource configuration after receiving the trigger message; It is set to do The PRS is a DL reference signal transmitted semi-persistently or a DL reference signal transmitted aperiodically. User Equipment (UE) (102).

15. The UE of claim 14, wherein the UE is further configured to perform a method according to any one of claims 2 to 11.

16. A user equipment (UE) (102), comprising: Receiving (s602) a configuration message comprising tracking reference signal (TRS) resource configuration information defining a TRS resource configuration; Receiving (s604) a trigger message transmitted by a base station (104), the trigger message comprising information for identifying the TRS resource configuration; receiving (s606) a TRS burst transmitted by the base station according to the TRS resource configuration identified by the information for identifying the TRS resource configuration after receiving the trigger message; wherein: In the time domain, the TRS bursts are present during at least three different symbols of a first slot; and / or In the frequency domain, the TRS burst has a density of at least 4 for at least the first slot. User Equipment (UE) (102).

17. A method (700) performed by a base station (104), the method comprising: transmitting (s702) to a user equipment (UE) (102) a configuration message comprising PRS resource configuration information defining a positioning reference signal (PRS) resource configuration; transmitting (s704) a trigger message to the UE, the trigger message comprising information for identifying the PRS resource configuration; After transmitting the trigger message, transmitting a PRS according to the PRS resource configuration identified by the information for identifying the PRS resource configuration (s506). Equipped with The PRS is a DL reference signal transmitted semi-persistently or a DL reference signal transmitted aperiodically. Method (700).

18. The method of claim 17 , wherein the information provided by the trigger message indicates whether to activate or deactivate the PRS resource configuration.

19. The method of claim 18 , wherein the resource configuration information comprises information regarding a configurable time period for receiving the PRS after the activation.

20. 20. The method of claim 18 or 19, wherein the PRS resource configuration information is received by Radio Resource Control (RRC) signaling, and the trigger message is a MAC Control Element (CE).

21. The method of claim 20, wherein the MAC CE indicates a serving cell ID, a TRP ID in the serving cell, and a PRS resource set ID in the TRP.

22. The method of claim 21 , wherein the MAC CE further comprises bit information indicating whether the PRS resource configuration should be activated or deactivated.

23. recording a first time value (T1) indicating a time when the base station transmitted the PRS; receiving an uplink reference signal transmitted by the UE; recording a second time value (T4) indicating a time at which the base station received the uplink reference signal transmitted by the UE; Calculating either T1-T4 or T4-T1; 23. The method of any one of claims 17 to 22, further comprising:

24. The method of claim 23, wherein the trigger message triggers the UE to transmit the uplink reference signal.

25. 25. The method of claim 24, wherein the PRS resource configuration comprises a pointer to an uplink configuration, and the UE is configured to transmit the uplink reference signal to the base station according to the uplink configuration.

26. The method according to any one of claims 17 to 25, wherein the base station configures the PRS of only one transmission and reception point (TRP) to the UE.

27. 27. The method of claim 26, wherein the one TRP is in a primary serving cell of the UE.

28. A method (800) performed by a base station (104), the method comprising: transmitting (s802) to a user equipment (UE) (102) a configuration message comprising tracking reference signal (TRS) resource configuration information defining a TRS resource configuration; transmitting (s804) a trigger message to the UE, the trigger message comprising information for identifying the TRS resource configuration; After transmitting the trigger message, transmitting a TRS burst according to the TRS resource configuration identified by the information for identifying the TRS resource configuration. Equipped with In the time domain, the TRS bursts are present during at least three different symbols of a first slot; and / or In the frequency domain, the TRS burst has a density of at least 4 for at least the first slot. Method (800).

29. A computer program (943) comprising instructions (944) which, when executed by a processing circuit (902) of a base station (104), cause the base station (104) to perform a method according to any one of claims 18 to 27.

30. A base station (104), transmitting (s702) to a user equipment (UE) (102) a configuration message comprising PRS resource configuration information defining a positioning reference signal (PRS) resource configuration; transmitting (s704) a trigger message to the UE, the trigger message comprising information for identifying the PRS resource configuration; After transmitting the trigger message, transmitting a PRS according to the PRS resource configuration identified by the information for identifying the PRS resource configuration (s506). It is set to do The PRS is a DL reference signal transmitted semi-persistently or a DL reference signal transmitted aperiodically. Base station (104).

31. The base station according to claim 30, wherein the base station is further configured to perform a method according to any one of claims 18 to 27.

32. A base station (104), transmitting (s802) to a user equipment (UE) (102) a configuration message comprising tracking reference signal (TRS) resource configuration information defining a TRS resource configuration; transmitting (s804) a trigger message to the UE, the trigger message comprising information for identifying the TRS resource configuration; After transmitting the trigger message, transmitting a TRS burst according to the TRS resource configuration identified by the information for identifying the TRS resource configuration. It is set to do In the time domain, the TRS bursts are present during at least three different symbols of a first slot; and / or In the frequency domain, the TRS burst has a density of at least 4 for at least the first slot. Base station (104).

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