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WO-2026096606-A1 - TIMING ADVANCE MAINTENANCE DURING LTM

WO2026096606A1WO 2026096606 A1WO2026096606 A1WO 2026096606A1WO-2026096606-A1

Abstract

A method can include receiving, by a wireless device, configuration parameter of a cell for conditional layer-1 or layer-2 triggered mobility (LTM) procedure. The configuration parameters can include a first parameter, for early uplink synchronization of the cell, indicating a first value of an LTM time alignment timer that is used to determine uplink time alignment with the cell. The configuration parameters can also include a second parameter, for radio resource control (RRC) reconfiguration of the cell, indicating a second value of a time alignment timer of the cell. The configuration parameters can further include one or more conditions to perform LTM cell switch to the cell.

Inventors

  • PRASAD, Gautham
  • KEATING, RYAN
  • KHOSHKHOLGH DASHTAKI, MOHAMMAD GHADIR
  • Dinan, Esmael Hejazi
  • YI, YUNJUNG
  • JEON, HYOUNGSUK
  • ZHOU, HUA
  • PARK, KYUNGMIN
  • KIM, TAEHUN
  • CIRIK, Ali Cagatay

Assignees

  • OFINNO, LLC

Dates

Publication Date
20260507
Application Date
20251029
Priority Date
20241029

Claims (20)

  1. 1. A method comprising: receiving, by a wireless device and via a cell, a radio resource control (RRC) configuration message comprising configuration parameters of a candidate cell for conditional layer 1 or 2 triggered mobility (LTM) procedure, wherein the configuration parameters comprise: a first parameter, for early uplink synchronization of the candidate cell, indicating a first value of an LTM time alignment timer that is used to determine uplink time alignment with the candidate cell; a second parameter, for RRC reconfiguration of the candidate cell, indicating a second value of a time alignment timer of the candidate cell; and one or more conditions to perform LTM cell switch to the candidate cell; starting the LTM time alignment timer in response to receiving, via the cell, an LTM timing advance (TA) medium access control (MAC) control element (CE) comprising a TA command that indicates a TA value of the candidate cell; starting the time alignment timer with a length of remaining time duration, of the LTM time alignment timer, in response to: determining the one or more conditions to be satisfied; and the LTM time alignment timer running; and transmitting, via the candidate cell, an uplink signal using the TA value based on the time alignment timer running.
  2. 2. A method comprising: receiving, by a wireless device, configuration parameter of a cell for conditional layer-1 or layer-2 triggered mobility (LTM) procedure, wherein the configuration parameters comprise: a first parameter, for early uplink synchronization of the cell, indicating a first value of an LTM time alignment timer that is used to determine uplink time alignment with the cell; a second parameter, for radio resource control (RRC) reconfiguration of the cell, indicating a second value of a time alignment timer of the cell; and one or more conditions to perform LTM cell switch to the cell.
  3. 3. A method comprising: starting, by a wireless device, a layer 1 or 2 triggered mobility (LTM) time alignment timer in response to receiving an LTM timing advance (TA) medium access control (MAC) control element (CE); Docket No.: 24-1245PCT starting a time alignment timer with a length of remaining time duration of the LTM time alignment timer in response to: determining one or more conditions for LTM to be satisfied; and the LTM time alignment timer running.
  4. 4. The method of claim 2, further comprising: starting, by a wireless device, a layer 1 or 2 triggered mobility (LTM) time alignment timer in response to receiving an LTM timing advance (TA) medium access control (MAC) control element (CE); starting a time alignment timer with a length of remaining time duration of the LTM time alignment timer in response to: determining one or more conditions for LTM to be satisfied; and the LTM time alignment timer running.
  5. 5. The method of claim 3, further comprising: receiving, by a wireless device, configuration parameter of a cell for conditional layer-1 or layer-2 triggered mobility (LTM) procedure, wherein the configuration parameters comprise: a first parameter, for early uplink synchronization of the cell, indicating a first value of an LTM time alignment timer that is used to determine uplink time alignment with the cell; a second parameter, for radio resource control (RRC) reconfiguration of the cell, indicating a second value of a time alignment timer of the cell; and one or more conditions to perform LTM cell switch to the cell.
  6. 6. The method of claim 4 or 5, wherein the LTM TA MAC CE indicates a TA value of the cell.
  7. 7. The method of claim 6, wherein the cell is a candidate cell.
  8. 8. The method of claim 7, further comprising transmitting, via the cell, an uplink signal using the TA value based on the time alignment timer running.
  9. 9. The method of any one of claims 1 to 8, wherein the uplink signal comprises at least one of: a physical uplink shared channel (PUSCH) transmission; a physical uplink control channel (PUCCH) transmission; and/or a sounding reference signal (SRS) transmission.
  10. 10. The method of any one of claims 1 to 9, wherein the uplink signal does not comprise a physical random-access channel (PRACH) transmission.
  11. 11. The method of any one of claims 1 to 10, further comprising transmitting a PRACH transmission.
  12. 12. The method of claim 11 , wherein the PRACH transmission comprises at least one of: a preamble; a message 1 ; or Docket No.: 24-1245PCT a message A.
  13. 13. The method of any one of claims 11 to 12, wherein the PRACH transmission is for a random-access procedure.
  14. 14. The method of claim 13, wherein the random-access procedure is for early uplink synchronization.
  15. 15. The method of any one of claims 1 to 14, wherein the configuration parameters comprise first configuration parameters for early uplink synchronization.
  16. 16. The method of claim 15, wherein the first configuration parameters comprise the first parameter.
  17. 17. The method of any one of claims 15 to 16, wherein the first configuration parameters indicate: one or more PRACH occasions; a timing advance offset value; a PRACH root sequence index; power control parameters; and a PRACH sub-carrier spacing value.
  18. 18. The method of claim 17, wherein the PRACH transmission is via the one or more PRACH occasions.
  19. 19. The method of any one of claims 17 to 18, wherein the PRACH transmission is using the PRACH subcarrier spacing value.
  20. 20. The method of any one of claims 17 to 19, wherein the PRACH transmission is based on the timing advance value.

Description

Docket No.: 24-1245PCT TITLE Timing Advance Maintenance during Mobility CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application claims the benefit of U.S. Provisional Application No. 63/713,450, filed October 29, 2024, which is hereby incorporated by reference in its entirety. BRIEF DESCRIPTION OF THE DRAWINGS [0002] Examples of several of the various embodiments of the present disclosure are described herein with reference to the drawings. [0003] FIG. 1A and FIG. 1B illustrate example mobile communication networks in which embodiments of the present disclosure may be implemented. [0004] FIG. 2A and FIG. 2B respectively illustrate a New Radio (NR) user plane and control plane protocol stack. [0005] FIG. 3 illustrates an example of services provided between protocol layers of the NR user plane protocol stack of FIG. 2A. [0006] FIG. 4A illustrates an example downlink data flow through the NR user plane protocol stack of FIG. 2A. [0007] FIG. 4B illustrates an example format of a MAC subheader in a MAC PDU. [0008] FIG. 5A and FIG. 5B respectively illustrate a mapping between logical channels, transport channels, and physical channels for the downlink and uplink. [0009] FIG. 6 is an example diagram showing RRC state transitions of a UE. [0010] FIG. 7 illustrates an example configuration of an NR frame into which OFDM symbols are grouped. [0011] FIG. 8 illustrates an example configuration of a slot in the time and frequency domain for an NR carrier. [0012] FIG. 9 illustrates an example of bandwidth adaptation using three configured BWPs for an NR carrier. [0013] FIG. 10A illustrates three carrier aggregation configurations with two component carriers. [0014] FIG. 10B illustrates an example of how aggregated cells may be configured into one or more PUCCH groups. [0015] FIG. 11A illustrates an example of an SS/PBCH block structure and location. [0016] FIG. 11 B illustrates an example of CSI-RSs that are mapped in the time and frequency domains. [0017] FIG. 12A and FIG. 12B respectively illustrate examples of three downlink and uplink beam management procedures. Docket No.: 24-1245PCT [0018] FIG. 13A, FIG. 13B, and FIG. 13C respectively illustrate a four-step contention-based random access procedure, a two-step contention-free random access procedure, and another two-step random access procedure. [0019] FIG. 14A illustrates an example of CORESET configurations for a bandwidth part. [0020] FIG. 14B illustrates an example of a CCE-to-REG mapping for DCI transmission on a CORESET and PDCCH processing. [0021] FIG. 15 illustrates an example of a wireless device in communication with a base station. [0022] FIG. 16A, FIG. 16B, FIG. 16C, and FIG. 16D illustrate example structures for uplink and downlink transmission. [0023] FIG. 17 illustrates an aspect of an example embodiment according to the present disclosure [0024] FIG. 18 illustrates an aspect of an example embodiment according to the present disclosure. [0025] FIG. 19 illustrates an aspect of an example embodiment according to the present disclosure. [0026] FIG. 20 illustrates an aspect of an example embodiment according to the present disclosure. [0027] FIG. 21 illustrates an aspect of an example embodiment according to the present disclosure. [0028] FIG. 22 illustrates an aspect of an example embodiment according to the present disclosure [0029] FIG. 23 illustrates an aspect of an example embodiment according to the present disclosure. [0030] FIG. 24 illustrates an aspect of an example embodiment according to the present disclosure. [0031] FIG. 25 illustrates an aspect of an example embodiment according to the present disclosure. DETAILED DESCRIPTION [0032] In the present disclosure, various embodiments are presented as examples of how the disclosed techniques may be implemented and/or how the disclosed techniques may be practiced in environments and scenarios. It will be apparent to persons skilled in the relevant art that various changes in form and detail can be made therein without departing from the scope. In fact, after reading the description, it will be apparent to one skilled in the relevant art how to implement alternative embodiments. The present embodiments should not be limited by any of the described exemplary embodiments. The embodiments of the present disclosure will be described with reference to the accompanying drawings. Limitations, features, and/or elements from the disclosed example embodiments may be combined to create further embodiments within the scope of the disclosure. Any figures which highlight the functionality and advantages, are presented for example purposes only. The disclosed architecture is sufficiently flexible and configurable, such that it may be utilized in ways other than that shown. For example, the actions listed in any flowchart may be re-ordered or only optionally used in some embodiments. [0033] Embodiments may be configured to operate as needed. The disclosed mechanism may be performed when certain criteria