Research On Detection Algorithm For LTE Uplink Multi-user MIMO System

Today, high speed broadband wireless access has become a hotspot of research and application, Long Term Evolution (LTE) is a representative of it, OFDM and MIMO are key technologies of LTE. Due to its low PAPR/CM compared with OFDM, single carrier frequency division multiple access (SC-FDMA) is adopted as uplink multiple access scheme in LTE. The generation of an SC-FDMA signal uses a DFT-S-OFDM structure. In order to increase the system capacity and user throughput, 3GPP standard adopts multiuser MIMO (MU-MIMO) in LTE uplink, so the MIMO signal detecting algorithms are indispensable process in LTE system design. This thesis mainly focuses on interference cancellation (IC) algorithm and sphere decoding algorithm (SDA) in LTE uplink MU-MIMO system.Firstly, system model of the LTE uplink MU-MIMO is introduced. Secondly, QR decomposition-based interference cancellation algorithm, and successive interference cancellation (SIC) algorithm and the parallel interference cancellation (PIC) algorithm are applied to LTE uplink MU-MIMO system.. After that, sphere decoding algorithms based on depth-first search strategy and breadth-first search strategy are researched in order to reduce the complexity of maximum likehood (ML) algorithm. And some improved algorithms are presented to improve the decoding efficiency. Finally, the BER performance of the IC algorithms and the SD algorithms mentioned in the thesis are simulated through Matlab tool, and the simulation results are analyzed.