Research And Implementation Of Detection Technology In TD-LTE-A Uplink

The continuous improvement in technology and society prompted the updation and evolution of mobile communication technology. Demand for faster and more convenient mobile communication has spawned the development of LTE and its evolution. The SCFDMA has been chosen as the transmission mode in LTE uplink. On the one hand, it can take advantage of the orthogonality between OFDM subcarriers to improve spectral efficiency. On the other hand, it can reduce the peak to average power ratio to improve power utilization. It’s particularly important to overcome the effects of the radio channel, and eliminate interference and signal loss casued by multipath and Doppler frequency shift. Therefore, how to efficiently and accurately recover the sending signals and ensure the reliability become more and more important. Based on this, signal detection technology in the receivinig end of TD-LTE-A uplink has been studied in this thesis.Firstly, this thesis introduces the key technologies of TD-LTE-A uplink. It analyzes the SC-FDMA characteristics and its generation method, then introduces MIMO technologies including Single-user SIMO, space division multiplexing and multi-user virtual MIMO transmission. At the same time, this thesis describes wireless channel simulation model used in LTE.Secondly, this thesis studies the detection technology for single-user SIMO and MIMO transmission system in-depth. For SIMO system, this thesis mainly studies the maximum ratio combining algorithms(MRC) and interference rejection combining algorithms(IRC). The iterative detection algorithm using soft information fromTurbo decoder is also introduced. Simulation results show that Turbo equalization algorithm combined with MRC can get performance gain. For MIMO detection technologies, this thesis introduces linear detection algorithms, traditional interference cancellation detection algorithms and soft interference cancellation detection algorithms based on soft information from Turbo decoder. There are two interference cancellation algorithms, serial and parallel. Simulation analysis for these detection algorithms are showed in the thesis on LTE uplink.Finally, based on the MIMO detection technologies studied earlier, combined with the actual needs of research and hardware conditions, the thesis selects the MMSE detection algorithm and implememt it in FPGA. Firstly, this thesis analyzes hardware implementation structure for MMSE detection algorithm, then uses ISE and Modelsim to do functional simulation of the hardware circuit. At last the designed circuit is downloaded to FPGA. Simulation waveforms and the data captured from the circuit prove the correctness of the circuit. The results meet the actual demand.