Cell Search via Phase Shifted Synchronization Signals
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Solution Overview
Problem
In wireless communication systems, mobile devices face challenges in differentiating between base stations when they transmit the same Primary Synchronization Channel (PSC) signal, hindering the ability to quickly identify and establish communication with the desired base station.
Innovation Solution
The solution involves shifting the PSC location for different base stations, allowing for varying PSC transmit timing, and applying phase shifts to Secondary Synchronization Channels (SSCs) with different cyclic shifts, enabling mobile devices to differentiate between base stations based on phase shift information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If base stations transmit the same Primary Synchronization Channel (PSC) signal, then signal consistency and simplicity are maintained, but mobile devices cannot differentiate between base stations
Solution Approach 1:
The patent applies local quality by introducing unique characteristics (phase shifts and time shifts) to specific components (PSC and SSC signals) of different base stations. While the overall system maintains consistency through standardized signal structures, individual base stations differentiate themselves through localized modifications to signal phase and timing, enabling mobile devices to distinguish between multiple base stations without changing the fundamental signal format.
Solution Approach 2:
The patent changes physical parameters of the synchronization signals - specifically phase and time shifts - to enable base station differentiation. By varying the phase of PSC/SSC signals and introducing time shifts between them across different base stations, the system allows mobile devices to identify and differentiate between base stations while maintaining signal structure consistency.
2Measurement precision
If mobile devices correlate received signals with all possible secondary synchronization codes to find frame synchronization, then accurate synchronization is achieved, but the cell search time increases significantly
Solution Approach 1:
The patent applies preliminary action by having mobile devices perform initial correlation with a reduced set of candidate signals based on detected phase and time shift characteristics. Instead of immediately correlating with all 64 possible secondary synchronization codes, the device first identifies potential candidates through preliminary observations of signal phase and timing, then performs detailed correlation only with those candidates, significantly reducing search time while maintaining synchronization accuracy.
Solution Approach 2:
The patent segments the cell search process into multiple stages: initial detection phase where devices identify signal characteristics, intermediate filtering phase where candidate base stations are narrowed down based on phase/time shift analysis, and final confirmation phase where precise frame synchronization is achieved. This segmentation allows the system to maintain measurement precision while reducing overall search time by avoiding exhaustive correlation with all possible codes in a single step.
Data Source
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AI summary
Systems and methodologies are described that facilitate searches for a cell in a wireless communication environment. A mobile device can employ a searcher that can detect timing information respectively associated with PSCs and cells to determine the cell with the highest correlation. The searcher can detect SSCs, which can include detecting associated phase information, to determine the SSC with the highest correlation, CP length, and/or other information to facilitate identifying a desired cell having the strongest signal to establish communication between the mobile device and the desired cell. PSCs respectively associated with cells can have different positions in the symbol sequences, and SSCs can respectively be phase shifted at different angles to facilitate detection and identification of a cell(s), where a PSC can be utilized as a phase reference by the associated SSC.