Study Of Antenna Selection Technologies Im Mimo-ofdm System

MIMO-OFDM technology can improve the capacity and the frequency utilization without increasing the transmitter power and the additional bandwidth. Through the frequency diversity technology of OFDM, frequency-selective fading channel can be converted into frequency flat fading channel, which can effectively overcome the inter-symbol interference. It is considered the key technologies for the next generation of mobile communication. The transmission/receiving antenna selection method can substantially reduce the RF cost with a little system performance loss, thus eliminating the limit of RF cost to MIMO-OFDM system. Antenna selection also can reduce the number of antennas in receiver, and resolve a lot of practical problems in the design of personal mobile terminal. These problems greatly restrict MIMO-OFDM development and application. Therefore, Antenna selection has been the key technology for next generation wireless communications.In this paper, the antenna selection techniques in MIMO-OFDM system have been studied based on the capacity and energy respectively. MCMC techniques then were applied to antenna selection for simplifying the calculation of the redundancy of the antenna combination.Capacity-based parts:Capacity of the system is firstly derived, and thus analysis its impact on the system capacity in two cases. Classic antenna selection methods in the single-carrier system were introduced. A receive antenna selection and its simplified method were method proposed which based on the subsystem and its simplified method. The simulation results show that the capacity performance of new method is Close to the optimal method, and its capacity preference is equal to the CMB method's. Of course, its capacity preference is better to no selection system's.Energy-based parts:space-time coding in the antenna selection system was firstly introduced, and then analysis the signal model and receiver structure of STBC-OFDM-MIMO system. On this basis, an antenna selection method based on energy has been improved, and this improved antenna selection method was applied to STBC-OFDM-MIMO systems. The simulation results show that by applying to STBC to system, the diversity degree and the bit error rate performance has been improvedFinally, the MCMC method was applied to antenna selection of MIMO-OFDM system. The MCMC iterative process and the protection strategy which applied to the antenna selection were described. The simulation results show that antenna selection using MCMC methods is better to traditional method's capacity performance, but the computing complexity has been simplified.