L1/L2 Mobility Timing Advance Sharing Across Candidate Cells

Solution Overview

Problem

The existing method of initiating multiple random access procedures in candidate cells for determining timing advances (TAs) leads to high power consumption and interference in terminal devices during cell switches, necessitating a reduction in the number of such procedures.

Innovation Solution

A method where a terminal device determines the timing advance of a target cell based on the timing advance of a first candidate cell, reducing the need for random access procedures by using contention-free random access preambles and shared TA information between network devices.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the terminal device initiates random access procedures in each candidate cell to obtain timing advances, then the timing advance information is acquired accurately, but the power consumption and random access interference increase significantly

Engineering Contradiction:

Improvetiming advance information accuracyVSAvoidterminal device power consumption

Core Design Contradiction:

Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent merges the random access procedures by allowing the terminal device to initiate random access in only one candidate cell (the first candidate cell) instead of each candidate cell. The timing advance information obtained from the first candidate cell is then shared with and applied to the target cell, combining multiple information needs into a single acquisition process.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The network device performs preliminary action by pre-configuring identification information that indicates the timing advance of the target cell can be determined based on the timing advance of the first candidate cell. This preliminary configuration enables the terminal device to skip redundant random access procedures in the target cell.

Inventive Principle:

Principle #10Preliminary action

2Measurement precision

If the terminal device initiates random access procedures in each candidate cell to obtain timing advances, then the timing advance information is acquired accurately, but the random access interference increases significantly

Engineering Contradiction:

Improvetiming advance information accuracyVSAvoidrandom access interference

Core Design Contradiction:

Measurement precisionVSObject-generated harmful factors

Solution Approach 1:

The patent merges the random access procedures by allowing the terminal device to initiate random access in only one candidate cell (the first candidate cell) instead of each candidate cell. The timing advance information obtained from the first candidate cell is then shared with and applied to the target cell, combining multiple information needs into a single acquisition process.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The network device performs preliminary action by pre-configuring identification information that indicates the timing advance of the target cell can be determined based on the timing advance of the first candidate cell. This preliminary configuration enables the terminal device to skip redundant random access procedures in the target cell.

Inventive Principle:

Principle #10Preliminary action

3Loss of information

If the terminal device initiates multiple random access procedures in candidate cells, then the timing advance information for all cells is obtained, but the communication efficiency decreases

Engineering Contradiction:

Improvetiming advance information completenessVSAvoidcommunication efficiency

Core Design Contradiction:

Loss of informationVSProductivity

Solution Approach 1:

The patent merges the random access procedures by allowing the terminal device to initiate random access in only one candidate cell (the first candidate cell) instead of each candidate cell. The timing advance information obtained from the first candidate cell is then shared with and applied to the target cell, combining multiple information needs into a single acquisition process.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The network device performs preliminary action by pre-configuring identification information that indicates the timing advance of the target cell can be determined based on the timing advance of the first candidate cell. This preliminary configuration enables the terminal device to skip redundant random access procedures in the target cell.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS20260032615A1Communication method and communication apparatus

Publication Date: 2026.01.29 HUAWEI TECH CO LTD

AI summary

This application provides a communication method and a communication apparatus applied to the field of L1/L2 triggered mobility. The method includes: A first network device receives a contention-free random access preamble of a first candidate cell; and the first network device sends an identifier of a target cell of a switch and timing advance (timing advance, TA) information of the target cell to a terminal device, where the target cell is a second candidate cell, and the TA information of the target cell is determined based on the contention-free random access preamble of the first candidate cell. The TA information of the candidate cell that the terminal device switches to and accesses may be determined based on the candidate cell for which the terminal device initiates the random access procedure.