Non-coherent Neighbor Cell Search Method for LTE
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Solution Overview
Problem
In conventional mobile cellular systems, particularly in 3GPP LTE, decoding neighbor cell IDs is challenging due to weak synchronization signals from neighbor cells, which are often interfered by stronger signals from the home cell, leading to inaccurate channel estimation and reduced detection accuracy.
Innovation Solution
A non-coherent neighbor cell search method that decodes the home cell ID and generates a combination signal by subtracting the home cell synchronization signal, allowing for correlation with possible neighbor cell sequences to identify the neighbor cell ID without channel estimation, thereby reducing errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional coherent detection is used to decode neighbor cell ID, then the detection process can be performed, but the detection accuracy is greatly reduced due to inaccurate channel estimation caused by interference from home cell signals
Solution Approach 1:
The patent extracts and removes the home cell synchronization signal component from the received signal before performing neighbor cell detection. By separating the strong home cell signal from the weak neighbor cell signal, the interference is eliminated and channel estimation accuracy is improved, directly resolving the technical contradiction between detection accuracy and channel estimation reliability
Solution Approach 2:
The patent applies preliminary processing to counteract the interference effect before detection. By pre-removing the home cell signal component and performing channel smoothing filtering in advance, the system prevents the interference from degrading the channel estimation, thereby maintaining both high detection accuracy and reliable channel estimation
2Measurement precision
If channel smoothing filter is applied to process detected channel responses, then the detection accuracy can be improved, but the amount of computation in the receiver increases
Solution Approach 1:
The patent applies channel smoothing filtering selectively and partially - only to the extent necessary to improve detection accuracy. By performing smoothing on the detected channel responses rather than processing the entire signal, the system achieves the needed accuracy improvement while limiting the increase in computational complexity to only what is essential
Data Source
AI summary
The present invention relates to a non-coherent neighbor cell search method for primary synchronization signal (PSS) and secondary synchronization signal (SSS). In order to eliminate the channel response of the home cell, the present invention utilizes the similarity of channel responses at adjacent subcarriers, components at the kth subcarrier and the (k+1)th subcarrier of the received signal are respectively multiplied by the conjugation of the corresponding local synchronization signal to respectively obtain the kth product and the (k+1)th product. Afterward, a combination signal is obtained by examining the difference of the kth product and the (k+1)th product. By mathematical simplification and analysis, the main unknown component of the combination signal is the synchronization signal of neighbor cell, also in a compound form. Thus, the neighbor cell ID can be obtained by performing the correlation operation of the combination signal to the compound reference sequence.