Candidate Cell Switching Using Shared Timing Advance
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Solution Overview
Problem
The existing method of cell switching in communication systems requires terminal devices to initiate multiple random access procedures in candidate cells, leading to high power consumption and interference, which needs to be reduced.
Innovation Solution
The method involves determining the timing advance (TA) of a target cell based on the TA of a first candidate cell, allowing the terminal device to skip random access procedures for the second candidate cell, and using contention-free random access preambles to improve communication efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the terminal device initiates random access procedures in each candidate cell to obtain TA, then the TA of candidate cells can be obtained, but the power consumption and random access interference increase
Solution Approach 1:
The network device pre-configures TA values for candidate cells and provides them to the terminal device before the cell switching occurs. This preliminary provision of TA information eliminates the need for the terminal device to perform random access procedures in each candidate cell, thereby reducing power consumption while ensuring reliable TA acquisition for the target cell
Solution Approach 2:
The invention extracts the TA acquisition process from the random access procedure. Instead of requiring the terminal device to initiate random access in each candidate cell to obtain TA, the network device separately provides TA information through dedicated signaling, separating the TA acquisition function from the random access mechanism and thereby reducing unnecessary random access operations and associated power consumption
2Reliability
If the terminal device initiates random access procedures in each candidate cell, then the TA of candidate cells can be obtained, but the random access interference increases
Solution Approach 1:
The network device pre-configures and provides TA values for candidate cells to the terminal device before cell switching occurs. This preliminary provision of TA information eliminates the need for multiple random access procedures in candidate cells, thereby reducing random access interference while ensuring reliable TA acquisition for the target cell
Solution Approach 2:
The invention extracts the TA acquisition process from the random access procedure. By providing TA information through dedicated network signaling rather than requiring terminal-initiated random access in each candidate cell, the harmful random access interference is reduced while maintaining reliable TA acquisition
3Reliability
If the terminal device initiates multiple random access procedures, then TA of multiple candidate cells can be obtained, but the communication efficiency decreases
Solution Approach 1:
The network device pre-configures TA values for multiple candidate cells and provides them to the terminal device before cell switching occurs. This preliminary provision of complete TA information for all candidate cells eliminates the need for multiple sequential random access procedures, thereby improving communication efficiency while ensuring complete TA acquisition for cell switching operations
Solution Approach 2:
The invention extracts the TA acquisition process from the random access procedure and implements it through dedicated network signaling. By providing TA information for multiple candidate cells through efficient downlink signaling rather than requiring multiple uplink random access procedures, the communication efficiency is improved while maintaining complete TA acquisition capability
Data Source
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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 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. Specifically, a candidate cell for which the terminal device initiates a random access procedure and a candidate cell that the terminal device switches to and accesses may be two different candidate cells, and 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. In this way, in this application, a quantity of random access procedures that need to be initiated by the terminal device can be reduced.