Research On MIMO Transmission Techniques Over Frequency Selective Channels With Nonlinear Power Amplifier

Multiple input multiple output (MIMO) technology can make full use of space resources, it can exponentially improve the channel capacity and the system performance without increasing transmit power by deploying multiple antennas intransceivers. MIMO technology has been a hot topic in the research of wireless communication system. Single carrier-frequency domain equalization (SC-FDE) is an effective way to combat effects of multipath transmission and to overcome high Peak to Average Power Ratio (PAPR) in Orthogonal Frequency Division Multiplexing (OFDM) system. Combining MIMO with SC-FDE, so called MIMO+SC-FDE, has been proposed as one of the effective anti-multipath techniques in the physical layer of IEEE802.16a standard.Although many scholars have carried out research in MIMO+SC-FDE wireless communication system and have made a great success, the performance of actual system is often affected by frequency selective fading channel and non-linearity introduced by high power amplifiers(HPA). Therefore, it is very meaningful to study the MIMO+SC-FDE system design in practical system with nonlinear amplifier.This thesis studies the high-speed data transmission in wireless systems with combined MIMO and SC-FDE. The main work is summarized as follows:(1) The space-time block coding technique for SC-FDE is studied,and the structure of space-time block code for SC-FDE system over frequency selective channel with nonlinear power amplifier is given. The appropriate modulation method, the frame structure, the space-time block coding and decoding algorithm, the channel equalization process under frequency-selective channel, the multi-antenna channel estimation algorithm and the noise power estimation algorithm are designed.(2) The beamforming algorithm in MIMO and SC-FDE are studied,and the implementation of beamforming in SC-FDE system over frequency selective channel with nonlinear power amplifier is given. The frame structure, the beamforming algorithm, the channel equalization process in the frequency selective channel and the channel estimation algorithm are designed. Finally, considering the characteristics of peak-to-average ratio after beamforming, the digital predistortion module of power amplifier is designed.(3)This thesis conducted extensive simulation evaluation for the whole system performance. By using the MATLAB language to build simulation platform, this thesis analyzes the bit error rate under different scenarios considering different antenna numbers, different relative movement speed between transmitter and receiver, and different nonlinear amplifier model, the simulation results are given and discussed.The simulateon results verify the feasibility of the designed scheme.