Cell Search Synchronization Subset Strategy for Unauthorized Bands
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Solution Overview
Problem
In wireless communication systems, particularly in LTE networks, the process of cell search and synchronization on unauthorized frequency bands is time-consuming, limiting the initial access, cell reselection, and handover of user equipment (UE), which hampers the efficient utilization of these bands due to higher priority systems like radar or WiFi.
Innovation Solution
A device and method that utilize a proper subset of synchronization signal sequences to rapidly search and synchronize with target cells on unauthorized frequency bands, reducing the number of matching sequences needed during cell search and thereby shortening the synchronization time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the UE performs cell search and synchronization on unauthorized frequency bands using the complete synchronization signal sequence set, then the cell search process is thorough and reliable, but the synchronization time is excessively long
Solution Approach 1:
The patent segments the complete synchronization signal sequence set into multiple subsets, each associated with specific frequency ranges. The UE divides the cell search process into stages: first searching using a reduced subset for rapid synchronization, then potentially expanding to the full set if needed. This segmentation resolves the contradiction by providing both speed (through subset search) and reliability (through selective full-set search).
Solution Approach 2:
The patent applies partial action by using only a necessary subset of the synchronization signal sequences rather than the complete set. For unauthorized frequency bands, a smaller subset suffices for initial synchronization, reducing search time while maintaining adequate reliability. The system can perform partial searches first, then expand to full searches only when necessary.
2Productivity
If the cell search process is expedited on unauthorized frequency bands, then the initial access and handover performance improves, but the risk of missing valid cells increases
Solution Approach 1:
The patent implements a dynamic cell search strategy where the UE adapts its search behavior based on frequency band characteristics. For unauthorized bands, the system dynamically selects reduced subsets for initial searches to improve speed, while maintaining the capability to perform comprehensive searches when reliability requirements demand. This dynamic approach resolves the contradiction between speed and detection accuracy.
Solution Approach 2:
The patent applies preliminary action by performing rapid subset-based searches first to quickly identify potential target cells on unauthorized frequency bands. This preliminary search phase expedites initial access without permanently compromising reliability, as the system can subsequently perform verification searches or expand to full-set searches if the preliminary results indicate need.
3Loss of time
If the UE uses a reduced subset of synchronization signal sequences for cell search, then the synchronization time is reduced, but the coverage of frequency ranges may be insufficient
Solution Approach 1:
The patent assigns different qualities (subset configurations) to different frequency ranges. Each frequency range is associated with specific synchronization signal subsets optimized for that range's characteristics. The UE adapts its search strategy based on the local frequency context, using appropriate subsets for unauthorized bands while maintaining full-set capability for authorized bands. This local quality approach resolves the contradiction by ensuring adequate coverage where needed while reducing time where possible.
Solution Approach 2:
The patent structures the synchronization signal sequences in a nested hierarchy where reduced subsets are contained within larger subsets, which in turn are contained within the complete set. The UE can navigate this nested structure by starting with inner subsets for rapid search and expanding outward to larger subsets or the complete set as needed. This nesting resolves the contradiction by providing scalable search coverage that adapts to timing requirements.
Data Source
AI summary
A terminal and base station side device, a terminal device, a base station, and a wireless communication method. The terminal side device includes a searching unit, configured to adopt a synchronization signal sequence corresponding to a target frequency range to be searched to search a target cell; and a synchronization unit, configured to perform synchronization based on the synchronization signal detected by the searching unit to synchronize the device to the target cell, the case the target frequency range belongs to a first frequency range, the searching unit adopts the synchronization signal sequence in a first subset of a synchronization signal sequence set to search the target cell, the first subset being a proper subset of the synchronization signal sequence set. Thereby, a number of synchronization signal sequence matching in a cell searching procedure is reduced and time for user equipment to synchronize to the target cell is shortened.