Based On Mimo-ofdm System, The Cdma Detection Algorithm And Multi-site Program

To achieve large capacity and subscribers' requirements of high-date-rate multimedia service, great breakthroughs in PHY layer are supposed to be made for future mobile communication system. MIMO-OFDM system is regarded as one of PHY layer solutions for next generation mobile communication system, because that MIMO system is able to increase the capacity of system, and that OFDM technology is good at combating frequency-selected fading. CDMA is a multiple access technique, which provides flexible access for subscribers and has high frequency reuse facter in cellular systems. Thus the integration of CDMA and MIMO-OFDM system will have a wide application in the future.This dissertation investigates detection algorithms and multiple access schemes in the uplink of CDMA-based MIMO-OFDM system, which is an effective integration of MIMO system, OFDM technique and CDMA scheme. The main innovations are briefly described as follows:The system model of CDMA-based MIMO-OFDM systems are firstly presented, according to MIMO-OFDM system model and several kinds of CDMA-like multiple access schemes in SISO-OFDM systems.Two kinds of User-Oriented Gradual Cancellation algorithms are proposed for CDMA-based MIMO-OFDM systems, i.e. User-Oriented Gradual Cancellation Zero Forcing (UO-GC-ZF) algorithm and User-Oriented Gradual Cancellation Minimum Mean Square Error (UO-GC-MMSE) algorithm. Accordingly, four sorting criterions, with different computational complexity and symbol error rate (SER) performance, are put forward, i.e. Average Symbol Error Ratio (ASER) criterion, Maximal Minimal Signal Noise Ratio (Max-Min-SNR) criterion, Maximal Maximal Signal Noise Ratio (Max-Max-SNR) criterion and Average Signal Noise Ratio (ASNR) criterion. In addition, the matrix inverse process for weighing vectors in the UO-GC-MMSE algorithm is simplified by Sherman-Morrison-Woodbury formula, in order to largely decrease the computational complexity. The computational complexity of two kinds of User-Oriented Gradual Cancellation algorithms are particularly analyzed and compared with that of traditional ZF and MMSE algorithms. Furthermore, the performance of User-Oriented Gradual Cancellation algorithms is demonstrated by Monte Carlo simulations, showing that SER performance of User-Oriented Gradual Cancellation algorithms with different sorting criterions is prior to that of traditional...