Method for eliminating interference of cell search in LTE system

Abstract

The invention discloses a method for eliminating interference of cell search in a LTE system. The method comprises the following steps of performing correlation operation on three groups of local PSS sequences and a received signal to obtain three groups of PSS correlation values; and for each group of PSS correlation values, searching first PSS correlation peak values arranged in an ascending order in the PSS correlation values by using a first threshold, and saving the PSS correlation peak value positions and a cell ID inter-group identifier; from the maximum PSS correlation peak value position, performing SSS correlation detection on the received signal for each PSS correlation peak value position, and successively detecting the PSS correlation peak values according to a descending order by using a second threshold, and after each correlation detection, reconfiguring a SSS signal at the maximum SSS correlation peak value in order to subtract the SSS signal from the corresponding position received signal to achieve SSS interference cancellation. The method can search relatively strong and weak cells at the same time, improves the downlink synchronization performance and handoff performance of the UE, and improves the user experience.

Description

technical field [0001] The present invention relates to the technical field of LTE (Long Term Evolution, long-term evolution project) system, in particular to a method for eliminating cell search interference in the LTE system. Background technique [0002] LTE is popularly known as 3.9G, with a data download capability of 100Mbps, and is regarded as the mainstream technology for the evolution from 3G to 4G. It improves and enhances the air access technology of 3G, and adopts OFDM and MIMO as the only standard for its wireless network evolution. If the UE (device) in the LTE system wants to communicate through the LTE cellular network, it needs to perform cell search to detect the physical layer cell identity of the cell. Since each cell corresponds to a pair of Primary Synchronization Signal (PSS) and Secondary Synchronization Signal (SSS), during cell search, UE can detect the physical layer cell identity (i.e. cell ID) of the cell by detecting PSS and SSS . Detecting t...

AI Technical Summary

Problems solved by technology

Since there are only three PSSs in the entire network, two adjacent cells may use the same PSS, so when the downlink synchronization signals of the two cells using the same PSS arrive at the UE basically at the same time, using the reconstruction method to eliminate interference will cause the two cells The PSS of the PSS is eliminated at the same time, so that only relatively strong cells can be searched, but relatively weak cells cannot be searched, so the PSS detection stage uses the reconstruction method to eliminate interference, which will lead to the searched in some scenarios. Incomplete community

For relatively weak cells, using the reconstruction method for PSS interference cancellation will cause PSS to be eliminated to the maximum extent due to inaccurate channel estimates, and will also introduce greater interference, resulting in weaker cells being undetectable

[0005] Since there are 504 SSSs, it is impossible for adjacent cells to use the same cell ID (identification), so the SSSs used by adjacent cells are different. The codes are the same, so the interference between two adjacent cells will become stronger. Simply using the zeroing method to eliminate SSS interference is not enough to eliminate the interference between the two cells in the current scenario.

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