Search

JP-2026514431-A - Terminal device and method

JP2026514431AJP 2026514431 AJP2026514431 AJP 2026514431AJP-2026514431-A

Abstract

An exemplary embodiment of the present disclosure relates to a solution for initiating a random access (RA) procedure. In this solution, a terminal device receives a first physical downlink control channel (PDCCH) order from a first network device to trigger a random access (RA) procedure for L1/L2 triggered mobility (LTM). The first PDCCH order indicates a first RA resource. The terminal device determines whether the first PDCCH order indicates a first cell of the first network device or a second cell of a second network device for handover. The terminal device is being serviced in the first cell. If the first PDCCH order indicates a second cell, the terminal device ignores the first RA resource in the first PDCCH order and initiates an RA procedure toward the second cell using the second RA resource. The second RA resource is configured for the terminal device by the second network device. [Selection Diagram] Figure 2

Inventors

  • リアン リン
  • ワン ガン

Assignees

  • 日本電気株式会社

Dates

Publication Date
20260511
Application Date
20230331

Claims (20)

  1. A terminal device equipped with a processor, The processor is connected to the terminal device, Receiving a first physical downlink control channel (PDCCH) order from a first network device that triggers a random access (RA) procedure, wherein the first PDCCH order indicates a first RA resource. The first PDCCH order determines whether it indicates a first cell of the first network device or a second cell of a second network device for handover, wherein the terminal device receives service in the first cell. In response to the determination that the first PDCCH order indicates the second cell, the first RA resource in the first PDCCH order is ignored, and the RA procedure is initiated toward the second cell using the second RA resource, wherein the second RA resource is configured to be set for the terminal device by the second network device. Terminal device.
  2. The processor further provides the terminal device with: In response to the determination that the first PDCCH order indicates the first cell, the system is configured to initiate the RA procedure toward the first network device using the first RA resource. The terminal device according to claim 1.
  3. The terminal device according to claim 1, wherein the second RA resource includes a non-collision type RA (CFRA) resource.
  4. The processor further provides the terminal device with: In response to the determination that the first PDCCH order indicates the second cell, it is determined whether at least one of the multiple candidate synchronization signal blocks (SSBs) associated with the RA opportunity has a signal quality exceeding a first quality threshold. In response to the determination that the at least one SSB has a signal quality exceeding the first quality threshold, the RA procedure is initiated using the CFRA resources based on the at least one SSB. In response to the determination that none of the plurality of candidate SSBs have a signal quality exceeding the first quality threshold, the RA procedure is configured to be initiated using the CFRA resource based on at least one of the plurality of candidate SSBs. The terminal device according to claim 3.
  5. The processor further provides the terminal device with: In response to a handover command, the handover procedure from the first cell to the second cell is performed. In response to a determination that the timing advance (TA) information for the second cell is unavailable or invalid, the CFRA resource is used to initiate further RA procedures toward the second cell. Regardless of whether the terminal device is configured to monitor RA responses (RARs), monitoring further RARs for the further RA procedure from the second network device, wherein the further RARs are configured to indicate at least the TA information of the second cell. The terminal device according to claim 3.
  6. The processor further provides the terminal device with: In response to the decision that the terminal device is configured not to monitor the RAR for the RA procedure, it is configured to determine that the RA procedure has been successfully completed after it has started. The terminal device according to claim 1.
  7. The processor further provides the terminal device with: In response to the decision that the terminal device is configured not to monitor the RAR for the RA procedure, it is determined that the RA procedure has not been completed successfully after it has been started. During the RA procedure, the RA preamble is transmitted to the second network device a predetermined number of times. The system is configured to determine that the RA procedure has been successfully completed after the RA preamble has been transmitted a predetermined number of times. The terminal device according to claim 1.
  8. The processor further provides the terminal device with: By setting the RAR timer to zero, the RAR for the RA procedure is monitored. In response to the determination that the RAR timer has expired, it is determined that the RA preamble in the RA procedure has been transmitted on the secondary cell (SCell). In response to the determination that the RA preamble has been sent on SCell, the system is configured to determine that the RA procedure has not been successfully completed. The terminal device according to claim 1.
  9. The processor further provides the terminal device with: In response to the decision that the terminal device is configured not to monitor the RAR for the RA procedure, it is determined that the RA procedure is not complete. The retransmission counter in the RA preamble in the aforementioned RA procedure is incremented. In response to the determination that the RA procedure is not completed and the retransmission counter is within the retransmission upper threshold, it is determined whether a second PDCCH order indicating the second cell has been received. In response to the determination that the second PDCCH order indicating the second cell has been received, the system is configured to perform the RA resource selection procedure. The terminal device according to claim 1.
  10. The processor further provides the terminal device with: In response to the decision that the terminal device is configured not to monitor the RAR for the RA procedure, it is determined whether the SSB signal quality for initiating the RA procedure exceeds a second quality threshold. In response to the determination that the signal quality of the SSB exceeds the second quality threshold, it is determined that the RA procedure has been successfully completed. The system is configured to determine that the RA procedure has not been completed successfully, based on the determination that the signal quality of the SSB does not exceed the second quality threshold. The terminal device according to claim 1.
  11. The processor further provides the terminal device with: In response to a decision that the terminal device is configured to monitor the RAR for the RA procedure, it is configured to monitor the RAR by monitoring downlink control information (DCI) using at least one of a first cell radio network temporary identifier (C-RNTI) set for the first cell, or a second C-RNTI set for the second cell. The terminal device according to claim 1.
  12. The processor further provides the terminal device with: If the reception of the RAR has not been completed successfully, and it has been determined that the DCI has been detected from the second network device using the second C-RNTI, then it is determined whether the third PDCCH order included in the DCI indicates the second cell. In accordance with the determination that the third PDCCH order indicates the second cell, The monitoring of the RAR is stopped, and the RA preamble in the RA procedure is retransmitted. It is set to be The terminal device according to claim 11.
  13. The processor further provides the terminal device with: In response to the determination that the third PDCCH order indicates the second cell, it is determined whether the third PDCCH order further indicates the second RA resource. In response to the determination that the third PDCCH order indicates the second RA resource, The monitoring of the RAR is stopped, and the RA preamble in the RA procedure is retransmitted. It is set to be The terminal device according to claim 12.
  14. The processor further provides the terminal device with: In response to the decision that the terminal device is configured to monitor the RAR for the RA procedure, the monitoring of the DCI using the second C-RNTI configured for the second cell is skipped, thereby enabling the monitoring of the RAR. The terminal device according to claim 1.
  15. A second network device comprising a processor, The processor is connected to the second network device, Setting up a second random access (RA) resource for a terminal device, wherein the terminal device is serviced in a first cell of a first network device, and the second RA resource includes a non-collision RA (CFRA) resource for the terminal device to initiate an RA procedure before the terminal device switches to a second cell of the second network device. After the terminal device switches from the first cell to the second cell, further RA procedures are performed with the terminal device using the second RA resource. Regardless of whether the terminal device is configured to monitor RA responses (RARs), the further RAR for the further RA procedure is transmitted to the terminal device, wherein the further RAR indicates at least the timing advance (TA) information of the second cell. It is set to be The second network device.
  16. The processor further provides the second network device with: Before the terminal device switches to the second cell, the RA procedure is executed with the terminal device. The method involves transmitting a third PDCCH order in the DCI to the terminal device using a second cell radio network temporary identifier (C-RNTI) set for the second cell, wherein the third PDCCH order indicates the second cell. The terminal device is configured to receive a retransmission of the RA preamble in the RA procedure. The second network device according to claim 15.
  17. The second network device according to claim 16, wherein the third PDCCH order further indicates the second RA resource.
  18. The terminal device receives a first physical downlink control channel (PDCCH) order from a first network device that triggers a random access (RA) procedure, wherein the first PDCCH order further indicates a first RA resource. The first PDCCH order determines whether it indicates a first cell of the first network device or a second cell of a second network device for handover, wherein the terminal device receives service in the first cell. In response to the determination that the first PDCCH order indicates the second cell, the first RA resource in the first PDCCH order is ignored, and the RA procedure is initiated toward the second cell using the second RA resource, wherein the second RA resource is configured for the terminal device by the second network device. A communication method that includes this.
  19. The second network device configures a second random access (RA) resource for a terminal device, wherein the terminal device is serviced in a first cell of the first network device, and the second RA resource includes a non-collision RA (CFRA) resource for the terminal device to initiate an RA procedure before the terminal device switches to the second cell. After the terminal device switches from the first cell to the second cell, further RA procedures are performed with the terminal device using the second RA resource. Regardless of whether the terminal device is configured to monitor RA responses (RARs), the further RAR for the further RA procedure is transmitted to the terminal device, wherein the further RAR indicates at least the TA information of the second cell. A communication method that includes this.
  20. When executed on at least one processor, the at least one processor stores an instruction causing it to execute the method according to claim 18 or the method according to claim 19. Computer-readable media.

Description

The exemplary embodiments of this disclosure generally relate to the field of communications technology, and more particularly to methods, apparatus, and media for initiating random access (RA) procedures. Communication systems are widely deployed to provide various telecommunications services. For example, device mobility within communication networks has been supported. The mobility function of communication networks can provide continuous coverage to devices, such as terminal devices, when they move from one cell to another (also known as inter-cell). For example, when a terminal device moves within a communication network, a handover or cell switch may occur during the movement. Support for Layer 1 (L1) or Layer 2 (L2) based inter-cell mobility, or L1/L2 triggered mobility (LTM), for handovers or cell switches has been proposed. Research on RA procedure initiation for LTM is ongoing. The above and other purposes, features, and advantages of this disclosure will become more apparent through a more detailed description of some exemplary embodiments of this disclosure in the accompanying drawings. This disclosure illustrates an exemplary communication environment in which exemplary embodiments may be implemented. The following are signaling flows for initiating an RA procedure according to some exemplary embodiments of the present disclosure. The process for initiating an RA procedure according to some exemplary embodiments of this disclosure is shown. The following are some exemplary embodiments of the present disclosure of signaling flows for random access channel (RACH) initiation and RAR monitoring. The following are signaling flows for RA procedures without RAR monitoring, according to some exemplary embodiments of this disclosure. The present disclosure shows a process for an RA procedure according to some exemplary embodiments. Figure 7A shows an illustrative diagram illustrating the timing of retransmission according to some exemplary embodiments of the present disclosure.Figure 7B shows an illustrative diagram illustrating the timing of retransmission according to some exemplary embodiments of the present disclosure. The present disclosure illustrates a process for an RA resource selection procedure according to some exemplary embodiments of this disclosure. This disclosure describes an alternative process for an RA procedure without RAR monitoring, according to some exemplary embodiments of this disclosure. The present disclosure describes a process for monitoring RAR with RNTI, according to some exemplary embodiments of this disclosure. This disclosure describes another process for monitoring RAR with RNTI, according to some exemplary embodiments of this disclosure. The following are some exemplary embodiments of the signaling flow for RA preamble retransmission of the present disclosure. A flowchart shows a method implemented in a terminal device according to some exemplary embodiments of this disclosure. Another flowchart shows a method implemented in a network device according to some exemplary embodiments of this disclosure. A simplified block diagram of an apparatus suitable for implementing an exemplary embodiment of the present disclosure is shown. Throughout the drawing, identical or similar reference numerals represent identical or similar elements. Next, the principles of this disclosure will be described with reference to several exemplary embodiments. These embodiments are provided for illustrative purposes only and are intended to help those skilled in the art understand and implement this disclosure, and should not be considered to imply any limitation on the scope of this disclosure. The embodiments described herein may be implemented in various other ways than those described below. In the following description and claims, unless otherwise defined, all technical and scientific terms used herein have the same meanings as those generally understood by an ordinary person skilled in the art to which this disclosure pertains. As used herein, the term "terminal device" refers to any device having wireless or wired communication capabilities. Examples of terminal devices include user equipment (UE), personal computers, desktops, mobile phones, cell phones, smartphones, personal digital assistants (PDA), portable computers, tablets, wearable devices, IoT (Internet of Things) devices, URLLC (Ultra-reliable and Low Latency Communication) devices, IoE (Internet of Everything) devices, Machine Type Communication (MTC) devices, V2X communication in-vehicle devices (X stands for pedestrian, vehicle, or infrastructure/network), and IAB (Integrated Access and This includes equipment for backhaul, spacecraft or aircraft in non-terrestrial networks (NTNs) with satellites, including HAP (High Altitude Platform) and satellite-based non-terrestrial networks (NTNs), XR (Extended Reality) devices that include various types of reality such as augmented reality (AR), mixed reality (MR), and virtual reali