Cell Handover Timing Advance Using Reference Signal Grouping
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Solution Overview
Problem
Determining the timing advance (TA) of a target cell during cell handover in communication systems is challenging, leading to increased random access and interruption delays.
Innovation Solution
Determine the TA of a target cell based on the downlink timing difference between reference signals of the target and source cells, eliminating the need for random access and improving accuracy through intra- or inter-frequency reference signal capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the terminal determines TA of the target cell through random access, then the TA can be obtained, but the random access process increases interruption delay
Solution Approach 1:
The terminal determines the TA of the target cell before completing the random access process by using the downlink timing difference between reference signals. This preliminary determination allows the terminal to prepare the TA value in advance, reducing the interruption delay when handover occurs.
Solution Approach 2:
The patent uses the downlink timing difference between reference signals as an intermediary to indirectly determine the TA of the target cell. Instead of directly obtaining TA through random access, the terminal calculates it based on the timing relationship between reference signals from the source and target cells, thereby avoiding the full random access procedure.
2Measurement precision
If the terminal uses traditional random access to obtain TA of target cell, then TA can be determined, but the process increases handover complexity
Solution Approach 1:
The patent extracts the essential function of TA determination from the complete random access process. By separating the TA determination step from the full random access procedure, the terminal can obtain the necessary TA value without executing the entire complex random access sequence, thereby simplifying the handover process.
Solution Approach 2:
The patent replaces the mechanical random access procedure with a calculation-based approach. Instead of physically performing the random access exchange, the terminal substitutes it with a timing difference calculation using reference signals, reducing the procedural complexity of handover.
Data Source
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Figure 2B
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AI summary
This application relates to the field of communication technologies, and discloses a communication method and apparatus. The method includes: A terminal receives first information, where the first information indicates that a first reference signal of a first cell and a second reference signal of a second cell belong to a same group; the terminal receives second information, where the second information indicates that the first cell is a target cell for handover; and the terminal accesses the target cell by using a timing advance TA of the target cell, where the TA of the target cell is determined based on a TA of the second cell, the first reference signal, and the second reference signal. According to the foregoing method, after determining, based on the first information, that the first reference signal and the second reference signal belong to the same group, the terminal may determine the TA of the target cell based on the TA of the second cell, the first reference signal, and the second reference signal, and does not need to obtain the TA of the target cell through random access. This reduces random access during cell handover and further reduces an interruption delay.