Research And Implementation Of LTE Co-Channel Cell Detection

Since lauched LTE has rapidly occupied the market because of its fast communication speed,flexible configuration and large system capacity.Before a new LTE base station is built,an electromagnetic environment analysis by frequency sweeping equipment is often needed.Therefore,accurate frequency sweeping method is the base of the normal operation of the system.In practical applications,LTE co-channel networking is very common,which also requires that frequency sweeping equipment have a good capability of co-channel cell detection.According to this requirement,this paper researches and implements LTE co-channel cell detection,which includes two functions:co-channel cell search and system message decoding.Among them,in order to decode the system message correctly,the channel estimation and multi antenna reception under co-channel interference is studied.Firstly,cell search under co-channel interference is studied.This paper divides scenes into half-frame asynchronous receiving and half-frame synchronous receiving according to relative receiving delay,and implements the cell search algorithm in these two scenes.Moreover,for the scene in which the signal is synchronously received,when the co-channel cells use the same primary synchronization signal,a secondary synchronization signal detection algorithm based on similarity judgment is proposed.Simulation results show that the proposed algorithm has better anti-interference ability and lower complexity than the traditional algorithm in the case of high signal-to-noise ratio.Secondly,channel estimation and multi antenna reception under co-channel interference is studied.For the scenes of symbol asynchronous receiving and symbol synchronous receiving,the corresponding channel estimation and multi antenna reception algorithm is implemented.Moreover,for the scene in which the signal is synchronously received,an improved serial interference cancellations scheme based on iterativing the interference rejection combining receiver is proposed.Simulation results show that the proposed scheme can effectively reduce the number of iterations required for correct decoding of the system without affecting the performance of the system.In general,the channel estimation and multi antenna reception scheme studied in this paper can effectively reduce the system block error rate under the co-channel interference and ensure the correct decoding of system messages.Finally,LTE co-channel cell detection system is implemented on the ZYNQ platform.In order to detect as many cells as possible,this paper designs several functional modules and their interactive connections,optimizes the system through means of fixed-point and priority processing.The results show that the platform implemented can complete co-channel cell search and system message decoding accurately.