Secondary Synchronization Channel Sequence Selection
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Solution Overview
Problem
In LTE systems, the existing cell search methods for neighboring cells in inter-base-station synchronous systems lead to degradation of secondary synchronization channel (S-SCH) transmission characteristics due to the use of shared sequences and transmission intervals, increasing the probability of interference and reducing detection efficiency.
Innovation Solution
A method is introduced where the base station selects multiple synchronization signal sequences and generates a secondary synchronization channel using parts of these sequences, allowing the mobile station to detect cell-specific information with reduced candidates, thereby preventing characteristic degradation and improving detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If shared sequences and transmission intervals are used for S-SCH in inter-base-station synchronous systems, then transmission resource utilization is improved, but S-SCH transmission characteristics are degraded due to interference between adjacent cells
Solution Approach 1:
The patent assigns different S-SCH sequences to different base stations or cell groups in a synchronous system. This local differentiation ensures that while resources are efficiently utilized across the network, each local cell maintains unique sequence characteristics, preventing interference and preserving transmission reliability in local areas.
2Measurement precision
If multiple synchronization signal sequences are selected and used for S-SCH generation, then detection accuracy of cell-specific information is improved, but processing load of mobile station increases
Solution Approach 1:
The patent performs S-SCH sequence selection in advance at the base station based on predetermined criteria such as cell ID or synchronization signal pattern. This preliminary action reduces the search space for mobile stations during cell search, improving detection accuracy while minimizing processing load by eliminating the need for exhaustive sequence testing.
Solution Approach 2:
The patent divides the set of available synchronization sequences into multiple groups or categories. Mobile stations can then focus their detection efforts on specific groups based on initial synchronization information, segmenting the overall detection task into smaller, more manageable subsets that reduce processing complexity while maintaining detection accuracy.
3Loss of time
If the number of S-SCH sequences is reduced to decrease mobile station processing load, then cell search time is reduced, but detection accuracy of cell-specific information is degraded
Solution Approach 1:
The base station performs preliminary selection and configuration of S-SCH sequences before transmission, organizing them in a structured manner that allows mobile stations to quickly identify relevant sequences. This preliminary organization enables mobile stations to reduce the number of sequences to test without sacrificing detection accuracy, thus reducing cell search time while maintaining reliable detection.
Data Source
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AI summary
A base station communicating with a mobile station in a radio communication system by using OFDM for downlink is disclosed. The base station includes a sequence selecting unit configured to select multiple synchronization signal sequences; a synchronization signal generating unit configured to generate a secondary synchronization channel based on a part of the selected synchronization signal sequences and another part of the selected synchronization signal sequences; and a transmitting unit configured to transmit the secondary synchronization channel. The secondary synchronization channel is used to detect cell-specific information.