Research On Combined Antenna And Subcarrier Allocation For MIMO-OFDM System

The future broadband wireless communication system exists two most serious challenges:multi-path fading channel and bandwidth efficiency. OFDM converts frequency selective multipath fading channel into a flat channel, thus reducing the impact of multipath fading. The multi-carrier of this multi-carrier transmission technology orthogonal each other, can make full use of spectrum resources. The full development of space resources—MIMO technology, generated independent of parallel channels as multiple data streams in space through using multiple antennas,without the need of additional spectrum resources and transmit power, and this technology effectively increases the channel capacity of the system. Combined antenna and subcarrier allocation system scheduler means that the system can adaptively select the antenna and sub-carrier for different users according to wireless channel fading characteristics. Combined antenna and subcarrier allocation can take advantage of the inherent diversity gain in the independent multi-user environment, that is, multiuser diversity, and the system's transmission efficiency and spectral efficiency will be improved significantly.This issue belongs to the basic theoretical research, and the purpose is to solve the existing shortcomings of antenna and subcarrier allocation in the MIMO-OFDM system with using intelligent optimization algorithm to find the optimal antenna and subcarrier joint distribution method as soon as possible, making full use of inherent diversity gain in the dependent multi-user environment, increasing channel capacity. In this paper, adaptive antennas and subcarrier allocation of MIMO-OFDM system based on particle swarm optimization algorithm is proposed. We conclude that the work mainly in the following areas:1. Sums up the MIMO-OFDM system, adaptive antennas and subcarrier allocation algorithm, particle swarm optimization and genetic algorithm research status; the shortcomings of current antenna and subcarrier allocation algorithm;2. For the defect of falling into local optimal with genetic algorithm, a Antenna and subcarrier allocation algorithm based on Particle Swarm Optimization is proposed.It generates a random vector as the original antenna and subcarrier allocation program,and uses capacity of the system as a fitness function, finding the best antenna and subcarrier allocation scheme by evolution. Simulation results show that this algorithm improves the channel capacity of the system under certain sending data rate and bit error rate;3. Adaptive antennas and subcarrier allocation based on Particle Swarm Optimization algorithm is programming with C language, and 8X8 antenna program will get the optimal allocation with just 0.017S,16X16 antenna 0.031S,which means that it can meet the hardware requirements.