Cell Switching Using Timing Advance to Skip Random Access

Solution Overview

Problem

Frequent movement of terminal devices triggers excessive random access procedures in candidate cells, leading to high power consumption and interference.

Innovation Solution

The terminal device reports timing advance (TA) information of candidate cells to the network device, allowing the network device to determine if random access procedures are necessary, thereby reducing the number of such procedures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the terminal device initiates random access procedures for all candidate cells to obtain timing advances, then the network device can ensure proper uplink synchronization, but the quantity of random access procedures increases excessively, leading to high power consumption and high random access interference

Engineering Contradiction:

Improveuplink synchronizationVSAvoidpower consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The terminal device performs random access procedures in advance for candidate cells before cell switching occurs. The obtained timing advance information is stored and reused when switching to these candidate cells, avoiding the need to perform random access procedures again after cell switching. This preliminary action ensures that timing synchronization is already established before the cell switch happens.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The network device pre-configures multiple candidate cells for the terminal device and indicates which cells have valid timing advance information. This allows the terminal device to identify which candidate cells can be accessed without performing random access procedures, thereby reducing the quantity of random access procedures while ensuring proper uplink synchronization.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If the terminal device initiates random access procedures for all candidate cells to obtain timing advances, then the network device can ensure proper uplink synchronization, but random access interference increases excessively

Engineering Contradiction:

Improveuplink synchronizationVSAvoidrandom access interference

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The terminal device performs random access procedures in advance for candidate cells before cell switching occurs. The obtained timing advance information is stored and reused when switching to these candidate cells, avoiding the need to perform random access procedures again after cell switching. This preliminary action ensures that timing synchronization is already established before the cell switch happens.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The network device provides feedback to the terminal device by indicating which candidate cells have valid timing advance information stored by the network. This feedback mechanism allows the terminal device to identify which candidate cells can be accessed without performing random access procedures, thereby reducing random access interference while ensuring proper uplink synchronization.

Inventive Principle:

Principle #23Feedback

3Productivity

If the terminal device reports timing advance information of candidate cells to the network device, then the quantity of random access procedures is reduced, but additional signaling overhead is introduced

Engineering Contradiction:

Improvecell switching efficiencyVSAvoidsignaling overhead

Core Design Contradiction:

ProductivityVSQuantity of substance

Solution Approach 1:

The timing advance information reporting mechanism is integrated into existing cell switching signaling procedures. The terminal device reports timing advance information for candidate cells using existing uplink signaling resources, and the network device uses this information to make cell switching decisions and provide feedback. This multi-functional approach allows the same signaling mechanism to serve both cell switching coordination and timing advance information exchange purposes.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentEP4693406A1Communication method and communication apparatus

Publication Date: 2026.02.11 HUAWEI TECH CO LTD

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AI summary

This application provides a communication method and a communication apparatus, which are applied to the field of L1/L2 triggered mobility. The method includes: A first network device receives information about a timing advance (timing advance, TA) of a first candidate cell, where the first candidate cell does not belong to the first network device; and the first network device sends an identifier of a target cell of a switch and first indication information to a terminal device, where the first indication information indicates to access the target cell in a random access channel-skip manner, and the target cell is the first candidate cell. Specifically, on the premise that the first network device has obtained the information about the TA of the first candidate cell, the first network device sends the first indication information and the identifier of the target cell (which is the first candidate cell) of the switch to the terminal device, so that the terminal device can directly access the target cell without initiating a random access procedure for the first candidate cell. In this way, a quantity of random access procedures initiated by the terminal device can be reduced.