Method and apparatus for improved determination of timing advance

Abstract

The embodiment of the invention relates to a method and a device for improving determination of timing advance. A user equipment (UE) may receive, from a first network entity, an indication of a configuration for the UE to report to the first network entity an estimate of a first timing advance value for a second network entity. The UE may determine an estimate of a first timing advance value. The UE may transmit to the first network entity an estimate of the first timing advance value or a reference signal time difference associated with the estimate of the first timing advance value for the second network entity. The UE may receive, from the first network entity, an indication of an error value associated with the estimate of the first timing advance value. The UE may determine a second timing advance value based on an estimate of the first timing advance value and the error value. The UE may transmit communications using the second timing advance value.

Description

Technical Field

[0001] Example embodiments relate generally to wireless communications and, more particularly, but not exclusively, to methods, apparatus, and computer program products for improving determination of timing advance. Background Art

[0002] Some wireless devices may be configured to perform various operations to support user equipment (UE) mobility within a wireless communication system. For example, when a UE moves from a coverage area of ​​a first cell (e.g., a first distributed unit (DU)) to a coverage area of ​​a second cell (e.g., a second distributed unit (DU)), a serving cell change may be performed. For example, the serving cell of the UE may be switched from the first cell to the second cell. Current serving cell changes (e.g., handovers) utilize multiple types of layer 3 (L3) signaling, such as radio resource control (RRC) signaling. For example, a radio resource control (RRC) measurement may trigger a serving cell change (e.g., if the value of the RRC measurement meets a threshold), and downlink RRC signaling may be used for a serving cell change command or otherwise indicate a serving cell change. In some cases, an RRC reconfiguration message may indicate or otherwise trigger a change in a primary cell (PCell) and a primary secondary cell (PSCell). Additionally or alternatively, an RRC reconfiguration message may indicate or otherwise trigger the release and addition of a secondary cell (SCell). All cases may involve a complete layer 2 (L2) and layer 1 (L1) reset, which results in longer latency, greater overhead, and longer disruption time compared to similar procedures for beam switching mobility. Therefore, some L1 / L2 mobility enhancements that implement serving cell changes via L1 / L2 signaling can reduce latency, overhead, and disruption time compared to serving cell changes via L3 signaling.

[0003] Figure 1 An example of a signal flow diagram 100 illustrating a technique for L1 / L2 triggered mobility (LTM) is shown. The signal flow diagram 100 may include a UE 105 and a base station 110, which may perform the operations described herein. In some cases, the base station 110 may include one or more DUs and one or more centralized units (CUs). The flow diagram 100 may provide an illustrative example of an order or sequence of operations described herein, however, any order or sequence may be used. In some cases, one or more operations of the signal flow diagram 100 may not be performed or may be omitted. Additionally or alternatively, the UE 105 and the base station 110 may perform operations not shown in the signal flow diagram 100.

[0004] The signal flow chart 100 may be an example of a message sequence chart (MSC) of an LTM, which may be based on a change request to an LTM framework. The signal flow chart 100 may include one or more phases, such as a preparation phase (e.g., an LTM preparation phase), a synchronization phase (e.g., an early synchronization phase), an execution phase (e.g., an LTM execution phase), and a completion phase (e.g., an LTM completion phase). As shown, each phase may include one or more operations (e.g., one or more communications).

[0005] At 115, UE 105 may be in an RRC connected state. For example, an RRC connection between UE 105 and base station 110 may have been previously established. At 120, UE 105 may transmit (e.g., cause transmission) a measurement report (e.g., an RRC measurement report) to (e.g., toward) base station 110. At 125, base station 110 (e.g., a CU of base station 110) may prepare one or more target cells for LTM (e.g., one or more DUs of base station 110, one or more DUs of different base stations). At 130, base station 110 (e.g., a CU of base station 110) may provide LTM configuration for one or more prepared cells. For example, base station 110 may transmit LTM configuration of one or more prepared cells to UE 105. Additionally or alternatively, base station 110 may configure UE 105 with L1 measurements reported for LTM execution.

[0006] At 135, UE 105 may transmit an RRC configuration message to base station 110. The RRC configuration message may indicate that the RRC configuration is complete. At 140, UE 105 may perform uplink (UL) and downlink (DL) synchronization (e.g., early UL / DL synchronization) with the candidate cell, which may minimize or eliminate interruptions during LTM execution. Limiting interruptions may be an example of a key advantage of LTM compared to other handover procedures. For example, a handover procedure utilizing L3 signaling may involve an interruption caused by a synchronization procedure with a target cell.

[0007] At 145, the UE 105 may transmit one or more L1 measurements (e.g., beam measurements) of the target cell to the base station 110 (e.g., to the source cell), and the DU of the base station 110 may determine which cell the UE 105 should switch to (e.g., handover to). At 150, the base station 110 may determine which cell the UE 105 should switch to. At 155, the base station 110 may transmit a cell switching command to the UE 105. In some cases, the cell switching command may be a communication via a medium access control control element (MAC-CE) signaling. At 160, the UE 105 may be detached from the source (e.g., the source cell) and one or more configurations may be applied to the target (e.g., the target cell). For example, the UE 105 may disconnect from the first serving cell and establish a connection with the second serving cell.

[0008] At 165, UE 105 may perform a random access channel (RACH) procedure. The RACH procedure may be used to establish a connection with a second serving cell (e.g., a target serving cell). In some cases, UE 105 may not perform a RACH procedure. For example, if the timing advance (TA) of the target serving cell is still valid (e.g., based on the DL / UL synchronization performed at 140), UE 105 may not perform a RACH procedure. At 170, the LTM procedure may be completed. For example, UE 105 may have successfully established a connection with the target serving cell and the LTM procedure may be terminated.

[0009] Figure 2 An example of a signal flow diagram 200 illustrating a technique for L1 / L2 triggered mobility (LTM) is shown. The signal flow diagram 100 may include a UE 105, which may be an example of a corresponding UE 105, such as reference Figure 1 The signal flow diagram 100 may also include DU 201-a, DU 201-b, and CU 203. DU 201 and CU 203 may be components or virtualized entities of base station 110, as described in reference Figure 1 As described herein. UE 105, DU 201, and CU 203 may perform the operations described herein. Flowchart 200 may provide an illustrative example of an order or sequence of operations described herein, however, any order or sequence may be used. In some cases, one or more operations of signal flow chart 100 may not be performed or may be omitted. Additionally or alternatively, UE 105, DU 201-a, DU 201-b, and CU 203 may perform operations not shown in signal flow chart 100. As described herein, signal flow chart 200 may be a reference to Figure 1 For a more detailed example of the LTM architecture described in . Figure 1The described LTM architecture may not show details related to the split architecture of the base station 110 (eg, DU 201 and CU 203), but may include a more general description of the entire radio access network (RAN).

[0010] For the LTM preparation phase (e.g., from 205 to 223), CU 203 provides LTM configuration for the prepared cell (e.g., prepared DU 201). Additionally or alternatively, CU 203 configures UE 105 to have L1 measurement reports for LTM execution. Additionally or alternatively, CU 203 provides TA acquisition trigger criteria and associated configurations to the source DU (e.g., DU 201-a). Additionally or alternatively, CU 203 provides cell switching trigger criteria and necessary configurations to DU 201-a. The trigger criteria for TA acquisition and cell switching may be similar to the measurement event report trigger conditions or the validity of the acquired TA. In some cases, the trigger configuration may filter configuration (for L1 measurement), trigger offset, cell individual offset, etc.

[0011] At 205, UE 105 may transmit a measurement report (e.g., an L3 measurement report) to DU 201-a (e.g., a source DU, a source cell). At 207, DU 201-a may transmit a measurement report to CU 203. For example, DU 201-a may transmit an L3 measurement report to CU 203. Additionally or alternatively, DU 201-a may transmit an RRC message to CU 203. The RRC message may be a UL RRC message. In some cases, the RRC message may include a measurement report. At 209, CU 203 may determine (e.g., select) one or more target cells (e.g., DU 201-b) to prepare for LTM.

[0012] At 211, CU 203 may transmit a UE context establishment request to DU 201-b. Additionally or alternatively, CU 203 may receive a UE context establishment response from DU 201-b. At 213, CU 203 may transmit a UE context modification request to DU 201-a. Additionally or alternatively, CU 203 may receive a UE context modification response from DU 201-a. At 215, CU 203 may generate one or more RRC configurations (e.g., one or more RRC reconfigurations). The one or more RRC configurations may include a measurement configuration for L1 cell changes and a configuration for prepared cells. At 217, CU 203 may transmit (e.g., transfer) an RRC message (e.g., a DL RRC message) to DU 201-a. The RRC message may include one or more TA acquisition criteria, one or more cell switching criteria, or both.

[0013] At 219, DU 201-a may transmit an RRC reconfiguration to UE 105. At 221, UE 105 may transmit an indication of RRC reconfiguration completion to DU 201-a. At 223, DU 201-a may transmit (e.g., transmit) an RRC message (e.g., a UL RRC message) to CU 203. At 225, UE 105 may transmit an L1 measurement report to DU 201-a. At 227, DU 201-a may trigger or determine to trigger TA acquisition of a target cell (e.g., DU 201-b). At 229, DU 201-a may transmit a TA acquisition command to UE 105.

[0014] At 231, UE 105 may transmit a random access preamble to DU 201-b. UE 105 may transmit a random access preamble so that DU 201-b (e.g., a target DU) may estimate a TA between UE 105 and DU 201-b. At 233, DU 201-b may transmit a random access response. DU 201-b may transmit the random access response to CU 203 and DU 201-a. In some cases, CU 203 may receive the random access response and may retransmit the random access response to DU 201-a. In some cases, DU 201-a may transmit a random access response to UE 105.

[0015] At 235, UE 105 may transmit one or more L1 measurement reports to DU 201-a. The one or more L1 measurement reports may include one or more beam measurement reports for a prepared target cell (e.g., a target DU). At 237, DU 201-a may determine a serving cell change. For example, DU 201-a may determine to trigger a serving cell change and transfer UE 105 to DU 201-b. In some cases, DU 201-a may determine a serving cell (e.g., for handover) based on one or more L1 measurement reports. At 239, DU 201-a may trigger a serving cell change. In some cases, DU 201-a may use a MAC-CE command to trigger a serving cell change. Additionally or alternatively, DU 201-a may transmit a TA of a target cell (e.g., DU 201-b) to UE 105. If UE 105 does not receive a random access response (e.g., at 233), DU 201-a may transmit a TA (e.g., in a MAC-CE command).

[0016] At 241, UE 105 and DU 201-b may perform a random access procedure. For example, UE 105 may transmit one or more random access requests to DU 201-b. If the TA of the target cell (e.g., DU 201-b) is valid, UE 105 may skip (e.g., avoid performing) the random access procedure. At 243, UE 105 and DU 201-b may complete RRC configuration. At 245, DU 201-b may transmit an UL RRC message to CU 203. At 247, CU 203 may transmit a context release command (e.g., for UE context information) to DU 201-a. At 249, DU 201-a may transmit a context release complete (message) (e.g., for UE context information) to CU 203.

[0017] Figure 3 An example of a timing diagram 300 is shown. The timing diagram 300 may illustrate signaling between the UE 105, the TRP 305-a, and the TRP 305-b. The TRP 305 may be an example of a base station 110 or individual DUs of the base station 110, as shown in FIG. Figure 1 and 2 As shown, a first distance D1 between TRP 305-a and UE 105 may be less than a second distance D2 between TRP 305-b and UE 105. Therefore, there may be a relative time difference RTD between the time when UE 105 receives a first DL transmission from TRP 305-a and a second DL transmission from TRP 305-b.

[0018] In some cases, the UE 105 is able to acquire the TA of the transmit / receive point (TRP) 305 without a random access procedure (e.g., without random access signaling). As described herein, UE-based TA acquisition (e.g., without random access signaling) is a method for early TA acquisition. As shown in the figure, Figure 3 An example of UE-based TA acquisition is provided when UE 105 calculates the TA of TRP 305-b while being served by TRP 305-a. The TA (TA2) of TRP 305-b can be calculated using equation (1) shown below.

[0019] TA2=TA1+2RTD-2Realized(TAE)-OtherEstError (1)

[0020] In equation (1), TA1 is the TA of TRP 305-a, RTD is the relative time difference of the transmission times of simultaneous signals transmitted by any pair of TRPs (e.g., TRP 305-a and TRP305-b), Realized (TAE) is the achieved timing alignment error, and OtherError includes any error that may be caused by UL / DL reciprocity or estimator implementation / method errors. In 38.104, Section 6.5.3, TAE is defined in the context of multiple-input multiple-output (MIMO) transmissions from TRP 305, with a maximum value not exceeding 3000ns, and extensions to the definition of LTM are being discussed in 3GPP. A similar quantity related to transmissions from a pair of cells, referred to as cell phase synchronization accuracy, is defined in 38.133, Section 7.4. The cell phase synchronization accuracy for time division duplex (TDD) is defined as the maximum absolute deviation in frame start timing between any pair of cells on the same frequency with overlapping coverage areas. According to some protocols for wireless communications, a minimum threshold cell phase synchronization accuracy may be defined as 3000 nanoseconds (ns).

[0021] In the context of DL positioning, as a result of the transmission time delay involved in the signal transmission, the transmission timing error can be defined in 38.305, Section 3.1, which in turn can be defined as the time delay from the time the digital signal is generated at the baseband to the time the RF signal is transmitted from the Tx antenna. In addition, in 37.355, the location server can use the information element NR-RTD-info to provide time synchronization information between the reference TRP 305 and the list of neighboring TRPs 305. These definitions, information elements, and related mechanisms in the specification can enable the UE 105 to understand the timing misalignments in transmissions from different TRPs 305 and take them into account in the position estimate.

[0022] As described herein, two methods for early TA acquisition (e.g., UE-based TA estimation and RACH-based TA acquisition) may be used. In some cases, UE-based TA estimation may enable the UE 105 to estimate the TA of the target cell without any RACH procedures. For example, the UE may facilitate determining the TA based on existing DL measurements, thereby avoiding any additional signaling costs. This may prevent the UE 105 from experiencing any interruption due to the RACH procedure (e.g., each PRACH preamble transmission toward the target cell may be subject to an interruption between the UE 105 and the serving cell). Additionally, there may be no significant challenges to TA validity because the UE 105 may continue to estimate the TA and its mobility, which may reduce or eliminate TA invalidity issues.

[0023] On the other hand, UE-based TA estimation may be affected by estimation errors. When the reference signal time difference (RSTD) estimation error is large, it may cause misalignment in uplink synchronization. For example, UE-based TA estimation may not meet the uplink timing requirements, which may lead to failure of the RACH-free process. Additionally or alternatively, handover failure may occur. In asynchronous situations where the RSTD between cells may be larger than the cyclic prefix (CP) and therefore the estimation error may also be relatively large, this challenge may be relatively more significant.

[0024] In some cases, the RACH-based TA acquisition technique may be relatively more accurate than the RACH-free technique because the RACH-based technique uses UL channel transmissions to determine the TA and the evaluation may be performed at the target cell. Although the RACH-based TA acquisition technique provides higher accuracy than the RACH-free technique, the TA is valid for every millisecond (ms) that is not used by the UE 105 during mobility. In this case, the network may need to re-trigger the TA acquisition of the UE 105, which may result in additional interruption of the UE 105 and signaling overhead on the air interface and the F1 interface. Summary of the invention

[0025] In one aspect, a method includes: receiving, at a user equipment (UE) from a first network entity an indication of a configuration for the UE to report an estimate of a first timing advance value or a reference signal time difference (RSTD) for a second network entity to the first network entity; determining, at the UE, an estimate of the first timing advance value based at least in part on the received indication of the configuration; causing transmission of the estimate of the first timing advance value for the second network entity or a reference signal time difference associated with the estimate of the first timing advance value toward the first network entity; receiving, from the first network entity, an indication of an error value associated with the estimate of the first timing advance value for the second network entity, determining a second timing advance value based at least in part on the estimate of the first timing advance value and the error value, and causing transmission of one or more communications toward the second network entity using the second timing advance value.

[0026] In some cases, the configuration indicates that the UE is to report an estimate of the first timing advance value or RSTD for the second network entity based at least in part on availability of the second network entity. In some cases, where the configuration indicates that the UE is to report an estimate of the first timing advance value or RSTD for the second network entity based at least in part on one or more conditions being satisfied. In some cases, the configuration indicates that the UE is to report an estimate of the first timing advance value or RSTD for the second network entity based at least in part on one or more of: (i) a change in a beam of the second network entity used to determine the estimate of the first timing advance value or (ii) a change in an SSB of the second network entity used to determine the estimate of the first timing advance value.

[0027] In one embodiment, the method may include causing information associated with the second network entity to be transmitted toward the first network entity, the information including one or more of: (i) reference signal information for the second network entity, (ii) an identifier for the second network entity, or (iii) a carrier frequency for communicating with the second network entity. In some cases, receiving an indication of the error value further includes: receiving a medium access control control element (MAC-CE) including an indication of the error value from the first network entity. Other technical features will be apparent to those skilled in the art from the following drawings, description, and claims.

[0028] In one aspect, a method includes: causing, by a first network entity, transmission toward a user equipment (UE), an indication for the UE to report to the first network entity an estimate of a first timing advance value or a configuration of an RSTD for a second network entity; receiving from the UE an estimate of the first timing advance value for the second network entity; determining, by the first network entity, an error value associated with the estimate of the first timing advance value, wherein the determination is based at least in part on receiving the estimate of the first timing advance value; and causing, toward the UE, transmission of an indication of the error value associated with the estimate of the first timing advance value for the second network entity.

[0029] In one embodiment, the method may further include receiving a second timing advance value from the second network entity, wherein the error value is determined based at least in part on a comparison of the first timing advance value and the second timing advance value. In some cases, the configuration indicates that the UE is to report the first timing advance value or the estimate of the RSTD for the second network entity based at least in part on the availability of the second network entity. In some cases, the configuration indicates that the UE is to report the first timing advance value or the estimate of the RSTD for the second network entity based at least in part on one or more conditions being satisfied.

[0030] In some cases, the configuration indicates that the UE is to report an estimate of the first timing advance value or RSTD for the second network entity based at least in part on one or more of: (i) a change in a beam of the second network entity used to determine the estimate of the first timing advance value or (ii) a change in an SSB of the second network entity used to determine the estimate of the first timing advance value. In an embodiment, the method may also include receiving, from the UE, information associated with the second network entity, the information comprising one or more of: (i) reference signal information for the second network entity, (ii) an identifier for the second network entity, or (iii) a carrier frequency used to communicate with the second network entity.

[0031] In some cases, causing transmission of an indication of an error value further comprises causing transmission of a medium access control control element (MAC-CE) comprising an indication of the error value towards the UE. Other technical features will be apparent to those skilled in the art from the following figures, description, and claims. In one aspect, a method comprises: receiving, at a user equipment (UE) from a first network entity, an indication of a configuration for the UE to report to the first network entity whether the UE has estimated a first timing advance value for a second network entity; determining, at the UE, an estimate of the first timing advance value based at least in part on the received indication of the configuration; causing transmission of an indication of whether the UE has estimated the first timing advance value for the second network entity towards the first network entity; receiving a second timing advance value from the first network entity; determining a third timing advance value based at least in part on the first timing advance value and the second timing advance value, and causing transmission of one or more communications towards the second network entity using the third timing advance value.

[0032] In one embodiment, the method may further include determining an error value based at least in part on comparing the first timing advance value to the second timing advance value, wherein the UE determines a third timing advance value based at least in part on the error value. In some cases, the configuration further indicates that if the UE has estimated the first timing advance value for the second network entity, the UE is to report an identifier of the second network entity to the first network entity.

[0033] In some cases, the configuration further indicates that the UE is to perform one or more operations for determining a third timing advance value. In some cases, the configuration indicates that the UE is to report whether the UE has estimated the first timing advance value for the second network entity based at least in part on one or more conditions being satisfied. In some cases, the configuration indicates that the UE is to report whether the UE has estimated the first timing advance value for the second network entity based at least in part on one or more of (i) a change in a beam of the second network entity used to determine the estimate of the first timing advance value or (ii) a change in an SSB of the second network entity used to determine the estimate of the first timing advance value.

[0034] In some cases, in the case where the UE estimates a fourth timing advance value for the first network entity, the configuration indicates that the UE is to estimate the first timing advance value. In one embodiment, the method may also include causing information associated with the second network entity to be transmitted toward the first network entity, the information comprising one or more of the following: (i) reference signal information for the second network entity, (ii) an identifier for the second network entity, or (iii) a carrier frequency for communicating with the second network entity. Other technical features will be apparent to those skilled in the art from the following drawings, descriptions and claims.

[0035] In one aspect, a method includes causing transmission, by a first network entity, toward a user equipment (UE), of an indication of a configuration for the UE to report to the first network entity whether the UE has estimated a first timing advance value for a second network entity; receiving from the UE an indication of whether the UE has estimated the first timing advance value for the second network entity; and causing transmission of a second timing advance value toward the UE, wherein causing the transmission is based at least in part on receiving the indication of whether the UE has estimated the first timing advance value.

[0036] In some cases, the configuration further indicates that if the UE has estimated the first timing advance value for the second network entity, the UE is to report an identifier of the second network entity to the first network entity. In some cases, the configuration further indicates that the UE is to perform one or more operations for determining a third timing advance value. In some cases, the configuration indicates that the UE is to report whether the UE has estimated the first timing advance value for the second network entity based at least in part on one or more conditions being satisfied.

[0037] In some cases, the configuration indicates that the UE is to report whether the UE has estimated a first timing advance value for a second network entity based at least in part on one or more of (i) a change in a beam of the second network entity used to determine the estimate of the first timing advance value or (ii) a change in an SSB of the second network entity used to determine the estimate of the first timing advance value. In an embodiment, the method may further include receiving information associated with the second network entity from the UE, the information comprising one or more of: (i) reference signal information for the second network entity, (ii) an identifier for the second network entity, or (iii) a carrier frequency for communicating with the second network entity. Other technical features will be apparent to those skilled in the art from the following drawings, description, and claims.

[0038] In one aspect, a computing device includes a processor. The computing device also includes a memory storing instructions, which, when executed by the processor, configure the device to: receive, at a user equipment (UE) from a first network entity an indication of a configuration for the UE to report an estimate of a first timing advance value or RSTD for a second network entity to the first network entity; determine, at the UE, an estimate of the first timing advance value based at least in part on the indication of the received configuration; transmit toward the first network entity an estimate of the first timing advance value for the second network entity or a reference signal time difference associated with the estimate of the first timing advance value; receive from the first network entity an indication of an error value associated with the estimate of the first timing advance value for the second network entity; determine a second timing advance value based at least in part on the estimate of the first timing advance value and the error value; and cause one or more communications to be transmitted toward the second network entity using the second timing advance value.

[0039] In some cases, the first timing advance value configuration indicates that the UE is to report an estimate of the first timing advance value for the second network entity based at least in part on availability of the second network entity. In some cases, the first timing advance value configuration indicates that the UE is to report an estimate of the first timing advance value for the second network entity based at least in part on one or more conditions being satisfied. In some cases, the first timing advance value configuration indicates that the UE is to report an estimate of the first timing advance value for the second network entity based at least in part on one or more of (i) a change in a beam of the second network entity used to determine the estimate of the first timing advance value or (ii) a change in an SSB of the second network entity used to determine the estimate of the first timing advance value.

[0040] In some cases, the instructions further configure the apparatus to cause transmission of information associated with the second network entity toward the first network entity, the information comprising one or more of: (i) reference signal information for the second network entity, (ii) an identifier for the second network entity, or (iii) a carrier frequency for communicating with the second network entity. In some cases, the indication of the error value further comprises: receiving a medium access control control element (MAC-CE) including an indication of the error value from the first network entity. Other technical features will be apparent to those skilled in the art from the following drawings, description, and claims.

[0041] In one aspect, a computing device includes a processor. The computing device also includes a memory storing instructions that, when executed by the processor, configure the device to: cause a first network entity to transmit to a user equipment (UE) an indication for the UE to report to the first network entity an estimate of a first timing advance value or a configuration of an RSTD for a second network entity, receive from the UE an estimate of a first timing advance value for the second network entity, determine by the first network entity an error value associated with the estimate of the first timing advance value, wherein the determination is based at least in part on receiving the estimate of the first timing advance value, and cause an indication to be transmitted toward the UE of the error value associated with the estimate of the first timing advance value for the second network entity.

[0042] In some cases, the instructions further configure the apparatus to receive a second timing advance value from the second network entity, wherein the error value is determined based at least in part on a comparison of the first timing advance value and the second timing advance value. In some cases, the first timing advance value configuration indicates that the UE is to report an estimate of the first timing advance value for the second network entity based at least in part on an availability of the second network entity. In some cases, the first timing advance value configuration indicates that the UE is to report an estimate of the first timing advance value for the second network entity based at least in part on one or more conditions being satisfied.

[0043] In some cases, the first timing advance value configuration indicates that the UE is to report an estimate of the first timing advance value for the second network entity based at least in part on one or more of: (i) a change in a beam of the second network entity used to determine the estimate of the first timing advance value or (ii) a change in an SSB of the second network entity used to determine the estimate of the first timing advance value. In some cases, the instructions further configure the apparatus to receive information associated with the second network entity from the UE, the information comprising one or more of: (i) reference signal information for the second network entity, (ii) an identifier for the second network entity, or (iii) a carrier frequency used to communicate with the second network entity.

[0044] In some cases, the instructions further configure the device to: cause the indication of the error value to be transmitted further includes causing a medium access control control element (MAC-CE) including an indication of the error value to be transmitted toward the UE. Other technical features will be apparent to those skilled in the art from the following figures, description, and claims. In one aspect, a computing device includes a processor. The computing device also includes a memory storing instructions, which, when executed by the processor, configure the device to: receive, at a user equipment (UE), from a first network entity an indication that the UE reports to the first network entity whether the UE has estimated a configuration of a first timing advance value for a second network entity; determine, at the UE, an estimate of the first timing advance value based at least in part on the indication of the received configuration; transmit to the first network entity an indication of whether the UE has estimated the first timing advance value of the second network entity; receive a second timing advance value from the first network entity; determine a third timing advance value based at least in part on the first timing advance value and the second timing advance value; and cause one or more communications to be transmitted toward the second network entity using the third timing advance value.

[0045] In some cases, the instructions further configure the apparatus to determine an error value based at least in part on comparing the first timing advance value to the second timing advance value, wherein the UE determines a third timing advance value based at least in part on the error value. In some cases, in the event that the UE has estimated the first timing advance value for the second network entity, the first timing advance value configuration further indicates that the UE is to report an identifier of the second network entity to the first network entity.

[0046] In some cases, the third timing advance value configuration further indicates that the UE is to perform one or more operations for determining the third timing advance value. In some cases, the configuration indicates that the UE is to report whether the UE has estimated the first timing advance value for the second network entity based at least in part on one or more conditions being satisfied. In some cases, the configuration indicates that the UE is to report whether the UE has estimated the first timing advance value for the second network entity based at least in part on one or more of (i) a change in a beam of the second network entity used to determine the estimate of the first timing advance value or (ii) a change in an SSB of the second network entity used to determine the estimate of the first timing advance value.

[0047] In some cases, in a case where the UE estimates a fourth timing advance value for the first network entity, the first timing advance value configuration indicates that the UE is to estimate the first timing advance value. In some cases, the instructions further configure the device to cause information associated with the second network entity to be transmitted toward the first network entity, the information comprising one or more of: (i) reference signal information for the second network entity, (ii) an identifier for the second network entity, or (iii) a carrier frequency for communicating with the second network entity. Other technical features will be apparent to those skilled in the art from the following drawings, description, and claims.

[0048] In one aspect, a computing device includes a processor. The computing device also includes a memory storing instructions, which, when executed by the processor, configure the device to: cause a first network entity to transmit to a user equipment (UE) an indication of a configuration for the UE to report to the first network entity whether the UE has estimated a first timing advance value for a second network entity; receive from the UE an indication of whether the UE has estimated the first timing advance value for the second network entity; and transmit to the UE a second timing advance value, wherein the transmission is based at least in part on receiving the indication of whether the UE has estimated the first timing advance value.

[0049] In some cases, when the UE has estimated a first timing advance value for the second network entity, the first timing advance value configuration further indicates that the UE is to report an identifier of the second network entity to the first network entity. In some cases, the third timing advance value configuration further indicates that the UE is to perform one or more operations for determining a third timing advance value.

[0050] In some cases, the configuration indicates that the UE is to report whether the UE has estimated the first timing advance value for the second network entity based at least in part on one or more conditions being satisfied. In some cases, where the configuration indicates that the UE is to report whether the UE has estimated the first timing advance value for the second network entity based at least in part on one or more of (i) a change in a beam of the second network entity used to determine the estimate of the first timing advance value or (ii) a change in an SSB of the second network entity used to determine the estimate of the first timing advance value.

[0051] In some cases, where the instructions further configure the apparatus to receive information associated with the second network entity from the UE, the information includes one or more of: (i) reference signal information for the second network entity, (ii) an identifier for the second network entity, or (iii) a carrier frequency for communicating with the second network entity. Other technical features will be apparent to those skilled in the art from the following drawings, descriptions, and claims. In one aspect, a non-transitory computer-readable storage medium includes instructions that, when executed by a computer, cause the computer to: receive, at a user equipment (UE), from a first network entity an indication of a configuration for the UE to report an estimate of a first timing advance value or RSTD for a second network entity to the first network entity, determine, at the UE, an estimate of the first timing advance value based at least in part on the received indication of the configuration, cause transmission of an estimate of the first timing advance value for the second network entity or a reference signal time difference associated with the estimate of the first timing advance value toward the first network entity, receive from the first network entity an indication of an error value associated with the estimate of the first timing advance value for the second network entity, determine a second timing advance value based at least in part on the estimate of the first timing advance value and the error value, and cause transmission of one or more communications toward the second network entity using the second timing advance value.

[0052] In some cases, the first timing advance value configuration indicates that the UE is to report an estimate of the first timing advance value for the second network entity based at least in part on availability of the second network entity. In some cases, wherein the first timing advance value configuration indicates that the UE is to report an estimate of the first timing advance value for the second network entity based at least in part on one or more conditions being satisfied. In some cases, wherein the first timing advance value configuration indicates that the UE is to report an estimate of the first timing advance value for the second network entity based at least in part on one or more of (i) a change in a beam of the second network entity used to determine the estimate of the first timing advance value or (ii) a change in an SSB of the second network entity used to determine the estimate of the first timing advance value.

[0053] In some cases, the instructions further configure the computer to cause transmission of information associated with the second network entity toward the first network entity, the information comprising one or more of: (i) reference signal information for the second network entity, (ii) an identifier for the second network entity, or (iii) a carrier frequency for communicating with the second network entity. In some cases, receiving an indication of the error value further comprises receiving a medium access control control element (MAC-CE) including an indication of the error value from the first network entity. Other technical features will be apparent to those skilled in the art from the following drawings, description, and claims.

[0054] In one aspect, a non-transitory computer-readable storage medium includes instructions that, when executed by a computer, cause the computer to: cause a first network entity to transmit toward a user equipment (UE) an indication for the UE to report to the first network entity an estimate of a first timing advance value or a configuration of an RSTD for a second network entity, receive from the UE an estimate of the first timing advance value for the second network entity, determine, by the first network entity, an error value associated with the estimate of the first timing advance value, wherein the determination is based at least in part on receiving the estimate of the first timing advance value, and cause transmission toward the UE of an indication of the error value associated with the estimate of the first timing advance value for the second network entity.

[0055] In some cases, the instructions further configure the computer to receive a second timing advance value from the second network entity, wherein the error value is determined based at least in part on a comparison of the first timing advance value and the second timing advance value. In some cases, the first timing advance value configuration indicates that the UE is to report an estimate of the first timing advance value for the second network entity based at least in part on an availability of the second network entity. In some cases, the first timing advance value configuration indicates that the UE is to report an estimate of the first timing advance value for the second network entity based at least in part on one or more conditions being satisfied.

[0056] In some cases, the first timing advance value configuration indicates that the UE is to report an estimate of the first timing advance value for the second network entity based at least in part on one or more of: (i) a change in a beam of the second network entity used to determine the estimate of the first timing advance value or (ii) a change in an SSB of the second network entity used to determine the estimate of the first timing advance value. In some cases, the instructions further configure the computer to receive information associated with the second network entity from the UE, the information comprising one or more of: (i) reference signal information for the second network entity, (ii) an identifier for the second network entity, or (iii) a carrier frequency used to communicate with the second network entity.

[0057] In some cases, causing transmission of an indication of an error value further comprises causing transmission of a medium access control control element (MAC-CE) including an indication of the error value toward the UE. Other technical features will be apparent to those skilled in the art from the following figures, description, and claims. In one aspect, a non-transitory computer-readable storage medium, the computer-readable storage medium comprising instructions, which when executed by a computer, causes the computer to: receive, at a user equipment (UE), from a first network entity an indication of a configuration for the UE to report to the first network entity whether the UE has estimated a first timing advance value for a second network entity, determine at the UE an estimate of the first timing advance value based at least in part on the received indication of the configuration, cause transmission of an indication of whether the UE has estimated the first timing advance value for the second network entity toward the first network entity, receive a second timing advance value from the first network entity, determine a third timing advance value based at least in part on the first timing advance value and the second timing advance value, and cause transmission of one or more communications toward the second network entity using the third timing advance value.

[0058] In some cases, the instructions further configure the computer to: determine an error value based at least in part on comparing the first timing advance value to the second timing advance value, wherein the UE determines a third timing advance value based at least in part on the error value. In some cases, if the UE has estimated the first timing advance value for the second network entity, the first timing advance value configuration further indicates that the UE is to report an identifier of the second network entity to the first network entity.

[0059] In some cases, the third timing advance value configuration further indicates that the UE is to perform one or more operations for determining the third timing advance value. In some cases, the configuration indicates that the UE is to report whether the UE has estimated the first timing advance value for the second network entity based at least in part on one or more conditions being satisfied. In some cases, the configuration indicates that the UE is to report whether the UE has estimated the first timing advance value for the second network entity based at least in part on one or more of (i) a change in a beam of the second network entity used to determine the estimate of the first timing advance value or (ii) a change in an SSB of the second network entity used to determine the estimate of the first timing advance value.

[0060] In some cases, in a case where the UE estimates a fourth timing advance value for the first network entity, the first timing advance value configuration indicates that the UE is to estimate the first timing advance value. In some cases, the instructions further configure the computer to: cause information associated with the second network entity to be transmitted toward the first network entity, the information comprising one or more of: (i) reference signal information for the second network entity, (ii) an identifier for the second network entity, or (iii) a carrier frequency for communicating with the second network entity. Other technical features will be apparent to those skilled in the art from the following drawings, description, and claims.

[0061] In one aspect, a non-transitory computer-readable storage medium includes instructions that, when executed by a computer, cause the computer to: cause a first network entity to transmit to a user equipment (UE) an indication of a configuration for the UE to report to the first network entity whether the UE has estimated a first timing advance value for a second network entity, receive from the UE an indication of whether the UE has estimated the first timing advance value for the second network entity, and cause transmission of a second timing advance value toward the UE, wherein causing the transmission is based at least in part on receiving the indication of whether the UE has estimated the first timing advance value.

[0062] In some cases, when the UE has estimated a first timing advance value for the second network entity, the first timing advance value configuration further indicates that the UE is to report an identifier of the second network entity to the first network entity. In some cases, the third timing advance value configuration further indicates that the UE is to perform one or more operations for determining a third timing advance value.

[0063] In some cases, the configuration indicates that the UE is to report whether the UE has estimated the first timing advance value for the second network entity based at least in part on one or more conditions being satisfied. In some cases, the configuration indicates that the UE is to report whether the UE has estimated the first timing advance value for the second network entity based at least in part on one or more of (i) a change in a beam of the second network entity used to determine the estimate of the first timing advance value or (ii) a change in an SSB of the second network entity used to determine the estimate of the first timing advance value.

[0064] In some cases, the instructions further configure the computer to receive information associated with the second network entity from the UE, the information comprising one or more of: (i) reference signal information for the second network entity, (ii) an identifier for the second network entity, or (iii) a carrier frequency for communicating with the second network entity. Other technical features will be apparent to those skilled in the art from the following figures, description, and claims. In some cases, the one or more conditions include one or more of: (i) a signal strength measurement for a signal received from the second network entity is greater than a signal strength measurement for a signal received from the first network entity, (ii) a signal strength measurement for a signal received from the second network entity satisfies a threshold, or (iii) one or more criteria associated with a beam quality of the second network entity are satisfied. BRIEF DESCRIPTION OF THE DRAWINGS

[0065] Having thus generally described certain exemplary embodiments of the present disclosure, reference will hereinafter be made to the accompanying drawings, which are not necessarily drawn to scale, and in which:

[0066] Figure 1 shows a signal flow diagram by which a user equipment (UE) and a base station can perform layer 1 / layer 2 triggered mobility (LTM) operations;

[0067] Figure 2 shows a signal flow diagram providing an example of additional signaling performed for LTM operations;

[0068] Figure 3 is an example of a timing diagram showing various delays between signals received from different transmit / receive points (TRPs);

[0069] Figure 4 A wireless communication system supporting techniques for determining timing advance (TA) according to examples described herein is shown;

[0070] Figure 5 An apparatus supporting improved techniques for determining TA according to examples described herein is shown;

[0071] Figure 6 A signal flow diagram for TA determination using network-based error estimation is shown;

[0072] Figure 7 A signal flow diagram is shown for TA determination using user equipment (UE) based error estimation; and

[0073] Figures 8 to 11 is a flow diagram of operations in accordance with certain example embodiments, such as implemented by an apparatus as described herein. DETAILED DESCRIPTION

[0074] Some embodiments of the present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which some, but not all, embodiments of the present invention are shown. Indeed, various embodiments of the present invention may be implemented in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that the present disclosure will satisfy applicable legal requirements. The same reference numerals always represent the same elements. As used herein, the terms "data," "content," "information," and similar terms may be used interchangeably to refer to data that can be transmitted, received, and / or stored according to certain embodiments of the present invention. Therefore, the use of any such terms should not be used to limit the spirit and scope of embodiments of the present invention.

[0075] Additionally, as used herein, the term "circuit" refers to (a) a hardware circuit implementation only (e.g., an implementation in analog circuits and / or digital circuits); (b) a combination of a circuit and a computer program product including software and / or firmware instructions stored on one or more computer-readable memories that work together to cause the device to perform one or more functions described herein; and (c) a circuit, such as a microprocessor or a portion of a microprocessor, that requires software or firmware for operation, even if the software or firmware is not physically present. This definition of "circuit" applies to all uses of this term herein, including in any claims. As another example, as used herein, the term "circuit" also includes an implementation including one or more processors and / or portions thereof and accompanying software and / or firmware. As another example, as used herein, the term "circuit" also includes, for example, a baseband integrated circuit or an application processor integrated circuit for a mobile phone or a similar integrated circuit in a server, a cellular network device, other network devices (e.g., a core network device), a field programmable gate array, and / or other computing devices.

[0076] As used herein, the term "computer-readable medium" refers to non-transitory storage hardware, non-transitory storage devices, or non-transitory computer system memory that can be accessed by a controller, microcontroller, computing system, or module of a computing system to encode computer-executable instructions or software programs thereon. The non-transitory "computer-readable medium" can be accessed by a computing system or module of a computing system to retrieve and / or execute computer-executable instructions or software programs encoded on the medium. Examples of non-transitory computer-readable media may include (but are not limited to) one or more types of hardware memory, non-transitory tangible media (e.g., one or more magnetic storage disks, one or more optical disks, one or more USB flash drives), computer system memory or random access memory (e.g., DRAM, SRAM, EDO RAM), etc.

[0077] Figure 4An example of a wireless communication system 400 that supports methods and apparatus for improved timing advance determination is shown. In some embodiments, the wireless communication system 400 may include one or more UEs 105 and one or more base stations 110 of a radio access network (RAN), which may communicate with each other. The one or more base stations 110 may be examples of network entities and may be implemented by any of a variety of access points or nodes including, for example, a Node B (e.g., a gNB) of the RAN. In some cases, the UE 105 and / or the RAN (e.g., the base station 110 of the RAN) may communicate with a core network including one or more network nodes of the core network. Figure 1 As shown, the base station 110 of the exemplary embodiment may include one or more CUs 203 and one or more DUs 201, which may be reference Figure 2 The description corresponds to an example of the CU 203 and the DU 201 .

[0078] As an example, the wireless communication system 400 may be deployed within a radio access architecture based on Long Term Evolution Advanced (LTE Advanced, LTE-A) and / or New Radio (NR, 5G). However, the system may be deployed in other network architectures, including in other communication networks, including, for example, other communication networks developed in the future, such as sixth generation (6G) networks, and any of many existing networks, including Universal Mobile Telecommunications System (UMTS), Radio Access Network (UTRAN or E-UTRAN), Wireless Local Area Network (WLAN or Wi-Fi), Worldwide Interoperability for Microwave Access (WiMAX), Personal Communications Service (PCS), Wideband Code Division Multiple Access (WCDMA), ultra-wideband (UWB) technology Sensor networks, mobile ad hoc networks (MANETs) and Internet Protocol multimedia subnets (IMS) or any combination thereof.

[0079] UE 105 can be any type of user terminal, terminal equipment, node (e.g., network node), element (e.g., network element), etc., to which resources on the air interface are allocated and assigned. For example, UE 105 can be a portable computing device, such as a wireless mobile communication device, including but not limited to the following types of equipment: a mobile station (mobile phone), a smart phone, a personal digital assistant (PDA), a handset, a device using a wireless modem (alarm or measuring device, etc.), a laptop and / or touch screen computer, a tablet computer, a game console, a notebook, a multimedia device, a car, a truck, an unmanned aircraft, an aircraft, and other types of vehicles. As a non-exhaustive list of some examples, UE 105 can also be referred to as a subscriber unit, a mobile station, a network element, a remote terminal, an access terminal, or a user terminal.

[0080] According to one or more aspects of the present disclosure, UE 105 and base station 110 may perform various techniques for determining (e.g., estimating) timing advance (TA) that effectively estimate timing error without introducing signaling overhead or TA validity challenges. In one embodiment, error estimation may be performed by the network. UE 105 may estimate the TA (e.g., TA1) of a target cell (e.g., target DU 201). UE 105 may then notify a serving cell (e.g., source cell, source DU 201) of the estimated TA. The serving cell (e.g., serving DU 201) triggers RACH-based TA acquisition for the same target cell (target cell, TA1 for which UE 105 has estimated TA), and acquires a TA (e.g., TA2). The serving DU then uses TA1 and TA2 to evaluate the estimated error of TA1 (including timing alignment error and other potential impairments). The serving DU provides the estimated error to UE 105, and UE 105 uses the estimated error to correct its TA estimate.

[0081] In another embodiment, the error estimation may be performed by the UE 105. The UE 105 may estimate the TA of the target cell (e.g., TA1). The UE 105 then informs the serving cell of the target cell for which the UE 105 has estimated the TA. The serving cell triggers RACH-based TA acquisition for the same target cell (e.g., the target cell for which the UE 105 has estimated the TA, TA1), and acquires the TA (e.g., TA2). The serving cell forwards the estimated TA (e.g., TA2) to the UE 105, and the UE 105 uses both TA1 and TA2 to estimate the estimation error. The UE 105 uses the estimated error value to correct its TA estimate.

[0082] In some cases, the UE 105 may also first be triggered using RACH-based TA acquisition, and directly receive the TA thereafter. The UE 105 may then be configured to continue the UE-based TA estimation taking into account the RACH-based TA acquired by the UE 105. Thus, in both solutions, the UE 105 may not need to reacquire the TA, since the TA invalidation problem may not occur. Additionally, the UE estimate may be corrected with this method, and the UE 105 may use the corrected TA estimate for RACH-free handover.

[0083] Figure 5 An example of an apparatus 500 supporting a method for improving determination of TA is shown. The apparatus 500 may be implemented by or may include a network element such as a UE 105 or a base station 110 configured to perform one or more operations for determining TA. Figure 5As shown, the device 500 may include a processing circuit 505 (e.g., one or more processors), a memory 510, and a communication interface 515, or be associated with or communicate with it. The processing circuit may communicate with the memory 510 via a bus for transferring information between components of the device. The memory 510 may be non-transitory and may include, for example, one or more volatile and / or non-volatile memories. In other words, for example, the memory 510 may be an electronic storage device (e.g., a computer-readable storage medium) that includes a storage component configured to store data (e.g., bits) that can be obtained by a machine (e.g., a computing device similar to the processing circuit 505). The memory 510 may be configured to store information, data, content, applications, instructions, etc. for enabling the device 500 to perform various functions according to the example embodiments of the present disclosure. For example, the memory 510 may be configured to buffer input data for processing by the processing circuit 505. In addition, or alternatively, the memory 510 may be configured to store instructions executed by the processing circuit 505.

[0084] In some embodiments, the device 500 may be included in various computing devices as described above. However, in some embodiments, the device 500 may be implemented as a chip or a chipset. In other words, the device 500 may include one or more physical packages (e.g., chips) that include materials, components, and / or wires on a structural assembly (e.g., a substrate). The structural assembly may provide physical strength, size savings, and / or limitations on electrical interactions for the component circuits included thereon. Therefore, in some cases, the device 500 may be configured to implement embodiments of the present invention on a single chip or as a single "system on a chip." Thus, in some cases, a chip or chipset may constitute a device for performing one or more operations to provide the functionality described herein.

[0085] The processing circuit 505 can be implemented in a variety of different ways. For example, the processing circuit 505 can be implemented as one or more of various hardware processing devices, such as a coprocessor, a microprocessor, a controller, a digital signal processor (DSP), a processing element with or without an accompanying DSP, or various other circuits including integrated circuits, such as ASIC (application-specific integrated circuit), FPGA (field programmable gate array), microcontroller unit (MCU), hardware accelerator, dedicated computer chip, etc. Therefore, in some embodiments, the processing circuit 505 may include one or more processing cores configured to be independently executed. Multi-core processing circuits can implement multi-processing within a single physical package. In addition, or alternatively, the processing circuit 505 may include one or more processors, which are configured in series via a bus to enable independent execution of instructions, pipelines and / or multi-threading.

[0086] In an exemplary embodiment, the processing circuit 505 may be configured to execute instructions stored in the memory 510 or instructions accessible to the processing circuit 505. Additionally or alternatively, the processing circuit 505 may be configured to execute hard-coded instructions. Similarly, whether configured by hardware or software methods, or by a combination thereof, the processing circuit 505 may represent an entity (e.g., physically contained in a circuit) capable of performing operations according to an embodiment of the present disclosure, while being configured accordingly. Thus, for example, when the processing circuit 505 is implemented as an ASIC, FPGA, etc., the processing circuit 505 may be hardware of a specific configuration for performing the operations described herein. Alternatively, as another example, when the processing circuit 505 is implemented as an executor of instructions, the instructions may specifically configure the processing circuit 505 to perform the algorithms and / or operations described herein when executing the instructions. However, in some cases, the processing circuit 505 may be a processor of a specific device (e.g., an image or video processing system) that is configured to adopt an embodiment of the present invention by further configuring the processing circuit 505 by instructions for performing the algorithms and / or operations described herein. Processing circuit 505 may include, among other things, a clock, an arithmetic logic unit (ALU), and logic gates configured to support the operation of processing circuit 505 .

[0087] The communication interface 515 can be any device, such as a device or circuit implemented in hardware or a combination of hardware and software, which is configured to receive and / or transmit data, including media content in the form of video or image files, one or more audio tracks, etc. In this regard, the communication interface 515 may include, for example, an antenna (or multiple antennas) and support for hardware and / or software for implementing communication with a wireless communication network (e.g., with one or more communication devices of the wireless communication system 100). Additionally or alternatively, the communication interface 515 may include one or more antennas to cause signal transmission via one or more antennas or process reception of signals received via one or more antennas. In some environments, the communication interface 515 may alternatively or also support wired communication. Thus, for example, the communication interface 515 may include a communication modem and / or other hardware / software for supporting communication via a cable, a digital subscriber line (DSL), a universal serial bus (USB), or other mechanisms.

[0088] In some cases, the device 500 may be configured to perform one or more tasks related to a use case application of artificial intelligence (e.g., using artificial intelligence for UE positioning). For example, the device 500 may be configured to use one or more machine learning models for one or more CSI processes, such as a CSI determination process. In this case, the device 500 may utilize the machine learning model to predict the CSI of one or more channels, which may enhance one or more operations performed by the device 500. In addition to machine learning-assisted CSI processes, the device 500 may utilize one or more artificial intelligence models for beam management, for positioning, or for any other type of operation performed by the device 500. However, utilizing artificial models for various operations at the device 500 may consume more resources than performing the same tasks without relying on artificial intelligence.

[0089] According to one or more aspects of the present disclosure, the device 500 may be configured (e.g., actively) to have a mapping table that links (e.g., associates, pairs) corresponding implementations (e.g., configurations, operations, features, functions, models, model parameters) for performing one or more tasks with corresponding required allocations of resources of the device 500, where resources refer to physical resources at the device or resources provided by another network entity for the device to perform the corresponding tasks. Then, the device 500 may select an implementation corresponding to the current status of the device 500, which may improve resource utilization and performance of the device 500.

[0090] Figure 6 An example of a signal flow diagram 600 supporting techniques for improved determination of a TA is shown. For example, the signal flow diagram 600 may support techniques for network-based error determination associated with a TA. The signal flow diagram 600 may include a UE 105, a DU 201-a, a DU 201-b, and a CU 203, which may perform the operations described herein. The flow diagram 600 may provide an illustrative example of an order or sequence of operations described herein, however, any order or sequence may be used. In some cases, one or more operations of the signal flow diagram 600 may not be performed or may be omitted. Additionally or alternatively, the UE 105, the DU 201-a, the DU 201-b, and the CU 203 may perform operations not shown in the signal flow diagram 600.

[0091] In some cases, the signal flow diagram 600 may illustrate an intra-CU scenario (e.g., having one CU 203 and multiple DUs 201 under the CU 203). However, the source DU (e.g., DU 201-a) and the target DU (e.g., DU 201-b) may be connected to different CUs 203. For example, the operations of the signal flow diagram 600 may also be applied to inter-CU and inter-DU mobility scenarios. Although not shown in the signal flow diagram 600, the initial operations may include the UE 105 establishing a connection with the DU 201-a. In addition, it should be noted that the UE 105 may have the capabilities of RACH-based early TA acquisition and UE-based TA estimation. Such UE capability information may be known at the network (e.g., as part of the UE capability information).

[0092] At 601, UE 105 may transmit a measurement report (e.g., an L3 measurement report) to DU 201-a (e.g., a source DU, a source cell). In addition, DU 201-a may transmit the measurement report to CU 203. At 603, CU 203 may make a handover determination. For example, CU 203 may select one or more target cells (e.g., DU 201-b) for handover. At 605, CU 203 may transmit a UE context establishment request to DU 201-b. Additionally or alternatively, CU 203 may receive a UE context establishment response from DU 201-b.

[0093] At 607, CU 203 may transmit a UE context modification request to DU 201-a. Additionally or alternatively, CU 203 may receive a UE context modification response from DU 201-a. At 609, CU 203 may generate one or more RRC configurations (e.g., one or more RRC reconfigurations). The one or more RRC configurations may include a measurement configuration for L1 cell changes and a configuration for prepared cells. At 611, CU 203 may configure UE 105 to report UE-based TA estimates. For example, CU 203 may send a configuration to UE 105 via DU 201-a indicating that the UE is to report a UE-based TA estimate. In one embodiment, the configuration directs UE 105 to report the TA estimate of the cell as soon as it is available. In another embodiment, if the cell with the estimated TA meets certain radio conditions, UE 105 reports the TA estimate (e.g., if its radio measurement is XdB stronger than the radio measurement for the serving cell or stronger than a threshold Y, or for the N best measured target cell beams). In one example, UE 105 may be configured to estimate and report the TA of a candidate cell again when the radio conditions of the candidate cell change (e.g., the best beam synchronization signal block (SSB) or SSB used to estimate the TA measurement is different than the SSB used for the previously reported TA value).

[0094] At 613, UE 105 may transmit an indication of the completion of RRC configuration (e.g., RRC reconfiguration) via DU 201-a. At 615, UE 105 reports one or more L1 measurements to DU 201-a. At 617, UE 105 performs TA estimation for DU 201-b. The process may be triggered by DU 201-a (e.g., based on the measurement report). For example, DU 201-a may send a MAC-CE to UE 105 that triggers UE 105 to perform TA estimation. At 619, based on the configuration received at 611, UE 105 may report the estimated TA to DU 201-a. In one embodiment, UE 105 may also include reference signal information (e.g., SSB index) of DU 201-b as well as cell ID and frequency for TA estimation.

[0095] At 621, DU 201-a may trigger or determine to trigger TA acquisition of the target cell (e.g., DU 201-b). In one embodiment, UE 105 may autonomously initiate RACH-based TA acquisition (e.g., the configuration of 611 may authorize UE 105 to perform RACH-based TA acquisition after reporting the estimated TA). UE 105 may select the same SSB to perform UE-based and RACH-based TA acquisition. At 611, contention-free random access (CFRA) resources may be provided to UE 105 for performing RACH. In some cases, if the estimated TA is above a certain threshold or the difference between the TA of the target cell and the TA of the serving cell exceeds a certain threshold, TA acquisition may be triggered for the target cell. In this case, the operation performed at 623 may not be performed (e.g., because the configuration may be given to UE 105 before 613).

[0096] At 623, if the UE 105 is not configured with autonomous TA acquisition and subsequently reporting the estimated TA, the UE 105 may receive a PDCCH ordered TA acquisition command to send a PRACH preamble to DU 201-b so that DU 201-b can estimate the TA. At 625, the UE 105 may transmit a random access preamble to DU 201-b. The UE 105 may transmit a random access preamble so that DU 201-b (e.g., target DU 201) can estimate the TA of DU 201-b. The UE 105 may send the PRACH preamble to DU 201-b as indicated by DU 201-a or as configured (e.g., at 611) together with a TA estimation report (e.g., a TA estimation report triggers a PRACH preamble transmission). At 627 , DU 201 - b evaluates the TA between UE 105 and DU 201 - b and transmits this evaluation to DU 201 - a via CU 203 .

[0097] At 629, DU 201-b transmits a random access response (RAR) to DU 201-a via CU 203. The RAR may include an indication of the TA. At 631, DU 201-a uses the TA reported by UE 105 (e.g., at 619) and the TA received from DU 201-b (e.g., at 629) to evaluate the estimated error of the TA reported at 619. At 633, DU 201-a may transmit the estimated error to UE 105 immediately after evaluating the estimated error. At 635, UE 105 may correct its TA estimate based on the estimated error. At 637, DU 201-a determines to trigger a serving cell change for UE 105. For example, DU 201-a may determine that DU 201-b is a new serving cell for UE 105.

[0098] At 639, DU 201-a may transmit a MAC-CE command to UE 105 to trigger a serving cell change. In some cases, the estimation error may be transmitted to UE 105 via a MAC-CE command. At 641, UE 105 may correct its TA estimate based on the estimation error. At 643, UE 105 may transmit an indication of RRC configuration completion to DU 201-b. At 645, DU 201-b may transmit an indication of RRC configuration completion to CU. In some cases, UE 105 may also be triggered by RACH-based TA acquisition and then directly receive TA. In this case, UE 105 may then be configured to continue UE-based TA estimation taking into account the RACH-based TA acquired by UE 105. The techniques described herein may be applied to conditional handover (CHO) to improve CHO performance (e.g., CHO without RACH). For CHO, once the conditions configured to UE 105 are met, UE 105 may autonomously perform handover configuration. Therefore, the UE 105 may not require any MAC-CE command for triggering a cell change.

[0099] Figure 7An example of a signal flow diagram 700 supporting techniques for improved determination of a TA is shown. For example, the signal flow diagram 700 may support techniques for network-based error determination associated with a TA. The signal flow diagram 700 may include a UE 105, a DU 201-a, a DU 201-b, and a CU 203, which may perform the operations described herein. The flow diagram 700 may provide an illustrative example of an order or sequence of operations described herein, however, any order or sequence may be used. In some cases, one or more operations of the signal flow diagram 700 may not be performed or may be omitted. Additionally or alternatively, the UE 105, the DU 201-a, the DU 201-b, and the CU 203 may perform operations not shown in the signal flow diagram 700.

[0100] In some cases, the signal flow diagram 700 may illustrate an intra-CU scenario (e.g., having one CU 203 and multiple DUs 201 under the CU 203). However, the source DU (e.g., DU 201-a) and the target DU (e.g., DU 201-b) may be connected to different CUs 203. For example, the operations of the signal flow diagram 700 may also be applied to inter-CU and inter-DU mobility scenarios. Although not shown in the signal flow diagram 700, the initial operations may include the UE 105 establishing a connection with the DU 201-a. In addition, it should be noted that the UE 105 may have the capabilities of RACH-based early TA acquisition and UE-based TA estimation. Such UE capability information may be known at the network (e.g., as part of the UE capability information).

[0101] At 701, UE 105 may transmit a measurement report (e.g., an L3 measurement report) to DU 201-a (e.g., a source DU, a source cell). In addition, DU 201-a may transmit the measurement report to CU 203. At 703, CU 203 may make a handover determination. For example, CU 203 may select one or more target cells (e.g., DU 201-b) for handover. At 705, CU 203 may transmit a UE context establishment request to DU 201-b. Additionally or alternatively, CU 203 may receive a UE context establishment response from DU 201-b. At 707, CU 203 may transmit a UE context modification request to DU 201-a. Additionally or alternatively, CU 203 may receive a UE context modification response from DU 201-a.

[0102] At 709, CU 203 may continue with the UE context establishment / modification process and may generate an RRC reconfiguration for the prepared LTM cell. CU 203 may also configure UE 105 to indicate whether the target cell (e.g., DU 201-b) has achieved UE-based estimation of TA. In another embodiment, if the cell with the estimated TA meets certain radio conditions, UE 105 may report the TA estimate (e.g., if its radio measurement is XdB stronger than the serving cell or stronger than a threshold Y, or for the n best measured target cell beams). In one example, UE 105 may be configured to estimate and report the TA of the candidate cell again when the radio conditions of the candidate cell change (e.g., the best beam (e.g., SSB) or the SSB used to estimate the TA measurement is different from the SSB used for the previously reported TA value). In another embodiment, the configuration causes UE 105 to trigger RACH-based TA acquisition to the target cell after achieving UE-based TA estimation for the same cell. Thus, the UE 105 may receive an indication and configuration for a UE autonomous RACH based TA acquisition procedure.

[0103] At 711, CU 203 may transmit a configuration indication to UE 105 via DU 201-a. At 713, UE 105 may transmit an indication of RRC configuration (e.g., RRC reconfiguration) completion via DU 201-a. At 715, UE 105 reports one or more L1 measurements to DU 201-a. At 717, UE 105 performs TA estimation for DU 201-b. This process may be triggered by DU 201-a (e.g., based on the measurement report). For example, DU 201-a may transmit a MAC-CE to UE 105 that triggers UE 105 to perform TA estimation.

[0104] At 719, based on the configuration received at 711, the UE 105 may indicate that it has estimated the TA of DU 201-b. In one embodiment, the UE 105 may also include RS information (e.g., SSB index) of the target cell for TA estimation as well as the cell ID and frequency (e.g., carrier frequency). At 721, DU 201-a may trigger or determine to trigger TA acquisition of the target cell (e.g., DU 201-b). In one embodiment, the UE 105 may autonomously initiate RACH-based TA acquisition (e.g., the configuration of 611 may authorize the UE 105 to perform RACH-based TA acquisition after reporting the estimated TA). The UE 105 may select the same SSB to perform UE-based and RACH-based TA acquisition. At 611, a contention-free random access (CFRA) resource for performing RACH may be provided to the UE 105. In some cases, TA acquisition may be triggered for the target cell if the estimated TA is above a certain threshold or the difference between the TA of the target cell and the TA of the serving cell exceeds a certain threshold. In this case, the operations performed at 623 may not be performed (eg, because the configuration may have been given to the UE 105 prior to 613).

[0105] At 723, if the UE 105 is not configured with autonomous TA acquisition and subsequently reporting an estimated TA, the UE 105 may receive a PDCCH ordered TA acquisition command to send a PRACH preamble to DU 201-b so that DU 201-b may estimate the TA. At 725, the UE 105 may transmit a random access preamble to DU 201-b. The UE 105 may send a random access preamble so that DU 201-b (e.g., target DU 201) may estimate the TA of DU 201-b. The UE 105 may transmit a PRACH preamble to DU 201-b as indicated by DU 201-a or as configured (e.g., at 611) together with a TA estimation report (e.g., a TA estimation report triggering a PRACH preamble transmission). At 727, DU 201-b evaluates the TA between UE 105 and DU 201-b and sends this evaluation to DU 201-a via CU 203. At 729, CU 203 may transmit a RAR to UE 105 via DU 201-a. The RAR may include the evaluation of the TA.

[0106] At 731, UE 105 may determine an estimation error based on the evaluation of the TA. At 733, UE 105 may apply the estimation error to correct its previously estimated TA. At 735, DU 201-a determines to trigger a serving cell change for UE 105. For example, DU 201-a may determine that DU 201-b is a new serving cell for UE 105. At 737, DU 201-a may transmit an indication of a cell change trigger to UE 105-a. The indication of a cell change trigger may be included in a MAC-CE. The MAC-CE may also include an indication of the TA of the target cell. At 739, UE 105 may utilize the corrected TA.

[0107] At 741, the UE 105 may transmit an indication of RRC configuration completion to the DU 201-b. At 745, the DU 201-b may transmit an indication of RRC configuration completion to the CU. In some cases, the UE 105 may also be triggered by RACH-based TA acquisition and directly receive the TA thereafter. In this case, the UE 105 may then be configured to continue UE-based TA estimation taking into account the RACH-based TA acquired by the UE 105. The techniques described herein may be applied to conditional handover (CHO) to improve CHO performance (e.g., CHO without RACH). For CHO, once the conditions configured to the UE 105 are met, the UE 105 autonomously performs the handover configuration. Therefore, the UE 105 may not require any MAC-CE command for triggering a cell change.

[0108] The techniques described herein may prevent the UE 105 from reacquiring the TA multiple times when the TA becomes invalid. The proposed method also improves the accuracy of the UE-based TA estimation. This may prevent unnecessary RACH-free failures (e.g., if RACH fallback is configured) that may result in delayed access. If RACH fallback is not configured, the proposed solution may prevent handover failures due to erroneous UE-based TA estimation. In addition, the techniques described herein may increase the size of the application domain of UE-based TA estimation for synchronous cells with relatively long CP to synchronous cells with relatively short CP as well as asynchronous cells.

[0109] Figure 8 An example of a flowchart 800 showing operations performed by an apparatus such as may be implemented by a UE 105, a base station 110, etc., as shown in FIG. Figures 1 to 7 described.

[0110] As shown in block 805, the apparatus may include receiving, at the UE from the first network entity, an indication of a configuration for the UE to report to the first network entity an estimate of a first timing advance value for a second network entity.

[0111] As indicated at block 810, the apparatus may include means, such as processing circuit 505, for determining, at the UE, an estimate of a first timing advance value based at least in part on receiving a configuration indication.

[0112] As indicated at block 815, the apparatus may include means, such as processing circuit 505, communication interface 515, etc., for causing transmission of an estimate of a first timing advance value for a second network entity or a reference signal time difference associated with the estimate of the first timing advance value toward the first network entity.

[0113] As represented by block 820, the apparatus may include means, such as processing circuitry 505, communication interface 515, etc., for receiving, from a first network entity, an indication of an error value associated with an estimate of a first timing advance value for a second network entity.

[0114] As indicated at block 825, the apparatus may include means, such as processing circuitry 505, for determining a second timing advance value based at least in part on the estimate of the first timing advance value and the error value.

[0115] As represented by block 830, the apparatus may include means, such as the processing circuit 505, the communication interface 515, etc., for transmitting one or more communications to the second network entity using the second timing advance value.

[0116] Fig. 9 An example of a flowchart 900 illustrating operations performed by an apparatus such as may be implemented by a UE 105, a base station 110, etc., as shown in FIG. Figures 1 to 7 described.

[0117] As shown in box 905, the device may include a module such as a processing circuit 505, a communication interface 515, etc., for causing the first network entity to transmit to a user equipment (UE) an indication of a configuration for the UE to report an estimate of a first timing advance value for a second network entity to the first network entity.

[0118] As represented by block 910, the apparatus may include means, such as the processing circuit 505, the communication interface 515, etc., for receiving an estimate of a first timing advance value of a second network entity from a UE.

[0119] As indicated at block 915, the apparatus may include means, such as processing circuit 505, for determining, by the first network entity, an error value associated with the estimate of the first timing advance value, wherein the determination is based at least in part on receiving the estimate of the first timing advance value.

[0120] As represented by block 920, the apparatus may include means, such as the processing circuit 505, the communication interface 515, etc., for transmitting to the UE an indication of an error value associated with an estimate of a first timing advance value for the second network entity.

[0121] Fig.10 An example of a flowchart 1000 showing operations performed by an apparatus such as may be implemented by a UE 105, a base station 110, etc., as shown in FIG. Figures 1 to 7 described.

[0122] As shown in box 1005, the device may include a module such as a processing circuit 505, a communication interface 515, etc., for receiving an indication from the first network entity at the UE that the UE reports to the first network entity whether the UE has estimated the configuration of the first timing advance value for the second network entity.

[0123] As represented by block 1010, the apparatus may include means, such as processing circuit 505, for determining, at a UE, an estimate of a first timing advance value based at least in part on receiving a configuration indication.

[0124] As indicated at block 1015, the apparatus may include means, such as processing circuit 505, communication interface 515, etc., for transmitting to the first network entity an indication of whether the UE has estimated a first timing advance value for the second network entity.

[0125] As represented by block 1020, the apparatus may include means, such as the processing circuit 505, the communication interface 515, etc., for receiving a second timing advance value from the first network entity.

[0126] As indicated at block 1025, the apparatus may include means, such as the processing circuit 505, for determining a third timing advance value based at least in part on the first timing advance value and the second timing advance value.

[0127] As represented by block 1030, the apparatus may include means, such as the processing circuit 505, the communication interface 515, etc., for transmitting one or more communications to the second network entity using the third timing advance value.

[0128] Fig.11 An example of a flowchart 1100 showing operations performed by an apparatus such as may be implemented by a UE 105, a base station 110, etc., as shown in FIG. Figures 1 to 7 described.

[0129] As shown in box 1105, the device may include modules such as processing circuit 505, communication interface 515, etc., for causing the first network entity to transmit to a user equipment (UE) an indication for the UE to report to the first network entity whether the UE has estimated the configuration of a first timing advance value for the second network entity.

[0130] As represented by block 1110, the apparatus may include means, such as processing circuit 505, communication interface 515, etc., for receiving an indication from a UE whether the UE has estimated a first timing advance value for a second network entity.

[0131] As indicated at block 1115 , the apparatus may include means, such as processing circuitry 505 , communication interface 515 , etc., for causing transmission of a second timing advance value toward the UE, wherein causing transmission is based at least in part on receiving an indication of whether the UE has estimated the first timing advance value.

[0132] Figures 6 to 11 Flowcharts and signal flow charts describing methods according to example embodiments are shown. It should be understood that each block or signal and combinations of blocks and signals can be implemented by various means, such as hardware, firmware, processors, circuits and / or other communication devices associated with the execution of software including one or more computer program instructions. For example, one or more of the above processes can be implemented by computer program instructions. In this regard, the computer program instructions embodying the above processes can be stored by the memory 510 of the device using the example embodiment and executed by the processing circuit 505. It is understood that any such computer program instructions can be loaded onto a computer or other programmable device (e.g., hardware) to produce a machine so that the resulting computer or other programmable device implements the functions specified in the flowchart blocks. These computer program instructions can also be stored in a computer-readable memory, which can instruct a computer or other programmable device to work in a specific manner so that the instructions stored in the computer-readable memory produce a product, the execution of which implements the functions specified in the flowchart blocks. The computer program instructions can also be loaded onto a computer or other programmable device so that a series of operations are performed on the computer or other programmable device, thereby producing a computer-implemented process so that the instructions executed on the computer or other programmable device provide operations for implementing the functions specified in the flowchart blocks.

[0133] Therefore, the blocks of the flowchart support a combination of means for performing the specified functions and a combination of operations for performing the specified functions. It will also be understood that one or more blocks of the flowchart and a combination of blocks in the flowchart can be implemented by a computer system based on special-purpose hardware that performs the specified functions or a combination of special-purpose hardware and computer instructions.

[0134] Benefiting from the teachings presented in the above description and the associated drawings, those skilled in the art to which the present invention belongs will think of many modifications and other embodiments of the present invention set forth herein. Therefore, it should be understood that the present invention is not limited to the specific embodiments disclosed, and modifications and other embodiments are intended to be included within the scope of the appended claims. In addition, although the above description and the associated drawings describe example embodiments in the context of certain example combinations of elements and / or functions, it should be understood that different combinations of elements and / or functions can be provided by replacing embodiments without departing from the scope of the appended claims. In this regard, for example, as can be set forth in some of the appended claims, combinations of elements and / or functions different from the elements and / or functions explicitly described above are also contemplated. Although specific terms are used here, they are only used in a general and descriptive sense, not for the purpose of limitation.

Claims

1. A device for wireless communication, comprising: at least one processor; as well as at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus to at least perform: receiving, at a user equipment UE, from a first network entity, an indication of a configuration for the UE to report to the first network entity an estimate of a first timing advance value for a second network entity; determining, at the UE, the estimate of the first timing advance value based at least in part on receiving the indication of the configuration; causing transmission of the estimate of the first timing advance value for the second network entity, or a reference signal time difference associated with the estimate of the first timing advance value, towards the first network entity; receiving, from the first network entity, an indication of an error value associated with the estimate of the first timing advance value for the second network entity; determining a second timing advance value based at least in part on the estimate of the first timing advance value, and the error value; as well as Using the second timing advance value causes one or more communications to be transmitted towards the second network entity.

2. The apparatus of claim 1, wherein the first timing advance value configuration indicates that the UE is to report the estimate of the first timing advance value for the second network entity based at least in part on availability of the second network entity.

3. The apparatus of claim 1, wherein the first timing advance value configuration indicates that the UE is to report the estimate of the first timing advance value for the second network entity based at least in part on one or more conditions being satisfied.

4. The apparatus of claim 3 , wherein the one or more conditions comprise one or more of: (i) a signal strength measurement for a signal received from the second network entity is greater than a signal strength measurement for a signal received from the first network entity, (ii) the signal strength measurement for the signal received from the second network entity satisfies a threshold, or (iii) one or more criteria associated with a beam quality of the second network entity are satisfied.

5. An apparatus according to claim 1, wherein the first timing advance value configuration indicates that the UE will report the estimate of the first timing advance value for the second network entity based at least in part on one or more of the following: (i) a change in a beam of the second network entity used to determine the estimate of the first timing advance value, or (ii) a change in an SSB of the second network entity used to determine the estimate of the first timing advance value.

6. The apparatus according to any one of claims 1 to 5, wherein the instructions further configure the apparatus to: Causing transmission of information associated with the second network entity toward the first network entity, the information comprising one or more of: (i) reference signal information for the second network entity, (ii) an identifier for the second network entity, or (iii) a carrier frequency for communicating with the second network entity.

7. The apparatus of any one of claims 1 to 6, wherein receiving the indication of the error value further comprises: A Medium Access Control - Control Element MAC-CE including said indication of said error value is received from said first network entity.

8. An apparatus for wireless communication, comprising: at least one processor; as well as at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus to at least perform: causing, by a first network entity towards a user equipment UE, transmission of an indication of a configuration for the UE to report to the first network entity an estimate of a first timing advance value for a second network entity; receiving, from the UE, the estimate of the first timing advance value for the second network entity; determining, by the first network entity, an error value associated with the estimate of the first timing advance value, wherein the determining is based at least in part on receiving the estimate of the first timing advance value; as well as causing transmission towards the UE of an indication of the error value associated with the estimate of the first timing advance value for the second network entity.

9. The apparatus of claim 8, wherein the instructions further configure the apparatus to: A second timing advance value is received from the second network entity, wherein the error value is determined based at least in part on a comparison of the first timing advance value and the second timing advance value.

10. The apparatus according to any one of claims 8 to 9, wherein the first timing advance value configuration indicates that the UE is to report the estimate of the first timing advance value for the second network entity based at least in part on availability of the second network entity.

11. The apparatus according to any one of claims 8 to 9, wherein the first timing advance value configuration indicates that the UE reports the estimate of the first timing advance value for the second network entity based at least in part on one or more conditions being satisfied.

12. The apparatus of claim 11, wherein the one or more conditions comprise one or more of: (i) a signal strength measurement for a signal received from the second network entity is greater than a signal strength measurement for a signal received from the first network entity, (ii) the signal strength measurement for the signal received from the second network entity satisfies a threshold, or (iii) one or more criteria associated with a beam quality of the second network entity are satisfied.

13. An apparatus according to any one of claims 8 to 9, wherein the first timing advance value configuration indicates that the UE will report the estimate of the first timing advance value for the second network entity based at least in part on one or more of the following: (i) a change in the beam of the second network entity used to determine the estimate of the first timing advance value, or (ii) a change in the SSB of the second network entity used to determine the estimate of the first timing advance value.

14. The apparatus of any one of claims 8 to 13, wherein the instructions further configure the device to: Information associated with the second network entity is received from the UE, the information comprising one or more of: (i) reference signal information for the second network entity, (ii) an identifier for the second network entity, or (iii) a carrier frequency for communicating with the second network entity.

15. The apparatus of any one of claims 8 to 14, wherein causing transmission of the indication of the error value further comprises: causing transmission of a Medium Access Control - Control Element MAC-CE comprising said indication of said error value towards said UE.

16. An apparatus for wireless communication, comprising: at least one processor; as well as at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus to at least perform: receiving, at a user equipment UE, from a first network entity, an indication for the UE to report to the first network entity whether the UE has estimated a configuration of a first timing advance value for a second network entity; determining, at the UE, the estimate of the first timing advance value based at least in part on receiving the indication of the configuration; causing transmission towards the first network entity of the indication whether the UE has estimated the first timing advance value for the second network entity; receiving a second timing advance value from the first network entity; determining a third timing advance value based at least in part on the first timing advance value and the second timing advance value; as well as Using the third timing advance value causes one or more communications to be transmitted towards the second network entity.

17. The apparatus of claim 16, wherein the instructions further configure the apparatus to: An error value is determined based at least in part on comparing the first timing advance value to the second timing advance value, wherein the UE determines the third timing advance value based at least in part on the error value.

18. The apparatus according to claim 16 or 17, wherein the first timing advance value configuration further indicates that if the UE has estimated the first timing advance value for the second network entity, the UE will report an identifier of the second network entity to the first network entity.

19. The apparatus according to any one of claims 16 to 18, wherein the third timing advance value configuration further indicates that the UE is to perform one or more operations for determining the third timing advance value.

20. The apparatus according to any one of claims 16 to 19, wherein the configuration indicates that the UE is to report whether the UE has estimated a first timing advance value for the second network entity based at least in part on one or more conditions being satisfied.

21. An apparatus according to claim 20, wherein the one or more conditions include one or more of the following: (i) a signal strength measurement for a signal received from the second network entity is greater than a signal strength measurement for a signal received from the first network entity, (ii) the signal strength measurement for the signal received from the second network entity satisfies a threshold, or (iii) one or more criteria associated with a beam quality of the second network entity are satisfied.

22. An apparatus according to any one of claims 16 to 21, wherein the configuration indicates that the UE will report whether the UE has estimated a first timing advance value for the second network entity based at least in part on one or more of the following: (i) a change in a beam of the estimated second network entity used to determine the first timing advance value, or (ii) a change in an SSB of the estimated second network entity used to determine the first timing advance value.

23. The apparatus according to any one of claims 16 to 22, wherein the first timing advance value configuration indicates that: in a case where the UE estimates a fourth timing advance value for the first network entity, the UE is to estimate the first timing advance value.

24. The apparatus of any one of claims 16 to 23, wherein the instructions further configure the apparatus to: Causing transmission of information associated with the second network entity toward the first network entity, the information comprising one or more of: (i) reference signal information for the second network entity, (ii) an identifier for the second network entity, or (iii) a carrier frequency for communicating with the second network entity.

25. An apparatus for wireless communication, comprising: at least one processor; as well as at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus to at least perform: Transmitting, by a first network entity, to a user equipment UE, an indication for the UE to report to the first network entity whether the UE has estimated a configuration of a first timing advance value for a second network entity; receiving, from the UE, an indication of whether the UE has estimated the first timing advance value for the second network entity; and Causing transmission of a second timing advance value towards the UE, wherein causing the transmission is based at least in part on receiving the indication of whether the UE has estimated the first timing advance value.

26. The apparatus of claim 25, wherein the first timing advance value configuration further indicates that, if the UE has estimated the first timing advance value for the second network entity, the UE is to report an identifier of the second network entity to the first network entity.

27. The apparatus according to claim 25 or 26, wherein the third timing advance value configuration further indicates that the UE is to perform one or more operations for determining the third timing advance value.

28. An apparatus according to any one of claims 25 to 27, wherein the configuration indicates that the UE is to report whether the UE has estimated a first timing advance value for the second network entity based at least in part on one or more conditions being satisfied.

29. The apparatus of claim 28, wherein the one or more conditions comprise one or more of: (i) a signal strength measurement for a signal received from the second network entity is greater than a signal strength measurement for a signal received from the first network entity, (ii) the signal strength measurement for the signal received from the second network entity satisfies a threshold, or (iii) one or more criteria associated with a beam quality of the second network entity are satisfied.

30. An apparatus according to any one of claims 25 to 29, wherein the configuration indicates that the UE will report whether the UE has estimated a first timing advance value for the second network entity based at least in part on one or more of: (i) a change in a beam of the estimated second network entity used to determine the first timing advance value, or (ii) a change in an SSB of the estimated second network entity used to determine the first timing advance value.

31. The apparatus of any one of claims 25 to 30, wherein the instructions further configure the apparatus to: Information associated with the second network entity is received from the UE, the information comprising one or more of: (i) reference signal information for the second network entity, (ii) an identifier for the second network entity, or (iii) a carrier frequency for communicating with the second network entity.

32. A method for wireless communication, comprising: receiving, at a user equipment UE, from a first network entity, an indication of a configuration for the UE to report to the first network entity an estimate of a first timing advance value for a second network entity; determining, at the UE, the estimate of the first timing advance value based at least in part on receiving the indication of the configuration; causing transmission of the estimate of the first timing advance value for the second network entity, or a reference signal time difference associated with the estimate of the first timing advance value, towards the first network entity; receiving, from the first network entity, an indication of an error value associated with the estimate of the first timing advance value for the second network entity; determining a second timing advance value based at least in part on the estimate of the first timing advance value, and the error value; as well as Using the second timing advance value causes one or more communications to be transmitted towards the second network entity.

33. A method for wireless communication, comprising: causing transmission by a first network entity towards a user equipment UE of an indication of a configuration for the UE to report to the first network entity an estimate of a first timing advance value for a second network entity; receiving, from the UE, the estimate of the first timing advance value for the second network entity; determining, by the first network entity, an error value associated with the estimate of the first timing advance value, wherein the determining is based at least in part on receiving the estimate of the first timing advance value; as well as causing transmission towards the UE of an indication of the error value associated with the estimate of the first timing advance value for the second network entity.

34. A method for wireless communication, comprising: receiving, at a user equipment UE, from a first network entity, an indication for the UE to report to the first network entity whether the UE has estimated a configuration of a first timing advance value for a second network entity; determining, at the UE, the estimate of the first timing advance value based at least in part on receiving the indication of the configuration; causing transmission towards the first network entity of an indication whether the UE has estimated the first timing advance value for the second network entity; receiving a second timing advance value from the first network entity; determining a third timing advance value based at least in part on the first timing advance value and the second timing advance value; as well as Using the third timing advance value causes one or more communications to be transmitted towards the second network entity.

35. A method for wireless communication, comprising: causing a first network entity to transmit, towards a user equipment UE, an indication for the UE to report to the first network entity whether the UE has estimated a configuration of a first timing advance value for a second network entity; receiving, from the UE, an indication of whether the UE has estimated the first timing advance value for the second network entity; and Causing transmission of a second timing advance value towards the UE, wherein causing the transmission is based at least in part on receiving the indication of whether the UE has estimated the first timing advance value.

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