Downlink Frame Synchronization via Segmented Cell Identification Codes
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Solution Overview
Problem
Existing cellular systems face challenges in rapid synchronization acquisition during initial synchronization and handover processes, particularly in heterogeneous networks, due to complex cell search procedures and difficulties in acquiring symbol synchronization within the required time frame.
Innovation Solution
A method for generating a downlink signal that includes arranging unique cell identification code groups and frame synchronization identification sequences in synchronization durations to form repetition patterns in the time domain, enabling rapid synchronization acquisition by converting the frame into a time domain signal and applying these sequences to achieve symbol and frame synchronization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If synchronization identification information is allocated only in the first time block, then the frame structure is simple, but rapid synchronization acquisition within 4.5 ms becomes impossible and diversity gain cannot be acquired
Solution Approach 1:
The frame is divided into multiple time blocks (first, second, third, fourth time blocks), with synchronization identification information allocated in the first and third time blocks. This segmentation allows the terminal to acquire synchronization from multiple locations within the 4.5 ms window, enabling rapid synchronization while maintaining a relatively simple overall frame structure.
2Reliability
If unique cell identification information or cell group identification information is correlated simultaneously with synchronization acquisition, then frame synchronization is achieved, but the cell search process becomes complex and rapid cell search is difficult
Solution Approach 1:
The cell search process is segmented into distinct stages: first acquiring synchronization identification information from synchronization sequences in the first and third time blocks, then separately acquiring unique cell identification information and cell group identification information from their respective allocated resources. This segmentation simplifies the overall cell search process while ensuring reliable frame synchronization.
Solution Approach 2:
Synchronization identification information is acquired first as a preliminary step before acquiring unique cell identification information and cell group identification information. This preliminary action enables the terminal to establish frame synchronization early, which then facilitates the subsequent cell identification processes in a structured manner.
3Loss of time
If a separate preamble is used to acquire synchronization, then synchronization can be acquired, but the terminal cannot be applied to systems without preamble and must wait for subsequent frame
Solution Approach 1:
Synchronization identification information is embedded within the existing downlink frame structure rather than using a separate preamble. This approach makes the system universally applicable to both systems with and without preambles, as the synchronization functionality is integrated into the standard frame structure that all terminals can process.
Solution Approach 2:
The synchronization identification information is merged with the downlink frame structure, specifically allocated in the first and third time blocks alongside other control information. This merging eliminates the need for separate preamble structures while maintaining synchronization capabilities, thereby improving system compatibility and adaptability.
Data Source
AI summary
An apparatus for generating a downlink signal and a cell search apparatus are disclosed. An apparatus for generating a downlink signal generates a downlink signal by one unique cell identification code group and a plurality of frame synchronization identification sequences, generates a downlink signal by a plurality of unique cell identification code groups and a plurality of frame synchronization identification sequences, or generates a downlink signal by a plurality of unique cell identification code groups and one frame synchronization identification sequence. A cell search apparatus obtains frame synchronization and identifies cells through a frame synchronization identification sequence and a unique cell identification code group.