Algorithm Research And DSP Implementation Of LTE Cell Search

LTE(Term Evolution Long)-Advanced is a long-term evolution of the fourth generation mobile communication.It is the new generation mobile communication technology standards most widely used.Cell search is a very important process in the physical layer of LTE downlink system,and the terminal equipment uses synchronous technology to complete the time synchronization of eNodeB downlink and detect the cell number to achieve cell search.By using the information obtained by cell search,the terminal equipment complete downlink system information is obtained by the demodulation of the PBCH(physical broadcast channel)and PDSCH(physical downlink shared channel).In the actual wireless network,there are many kinds of communication system,LTE system is the same frequency network and the whole network synchronization system,the same frequency interference from neighboring cells,spurious emission interference from other systems,large power signal interference from distance and other factors,resulting in the actual LTE network environment is very complex.How to achieve accurate cell search,guarantee the high quality of communication and detection of cell signal coverage is of great significance.In this paper,we have studied the existing LTE cell search technology,and introduce the basic principle,implementation method and the key technology of LTE Division OFDM(Frequency Orthogonal Multiplexing),and made a detailed analysis of the impact of the time-frequency deviation.The generation method and resource mapping in time-frequency domain of Primary Synchronization Signal(PSS),Secondary Synchronization Signal(SSS)and Cell Reference Signal(CRS)are introduced in detail.On the basis of the above,the PSS detection,Frequency offset estimation,CP detection,SSS detection algorithm are discussed.In combination with the performance of the existing algorithms and the applicability of the hardware,the primary synchronization signal detection algorithm is improved.The improved joint detection algorithm is proposed for the CellID detection algorithm,which can effectively filter the invalid cell and therelated information.After the comprehension of DSP chip,the algorithm is implemented in MSC8156 development environment.On the basis of understanding the hardware structure and optimization of MSC8156,the DSP code is optimized by different methods.The results show that the algorithm is feasible after verification.