Research On Energy Efficiency Optimization Based On Interference Alignment For Multi-user MIMO System

Multiple-input multiple-output(MIMO) is one of the most significant break throughs in recent years. While providing high capacity, MIMO also makes interference become increasingly significant and energy consumption grow rapidly. It’s not optimal merely improving system sum rate. To weigh the relation between sum rate and energy consumption, energy efficiency was put forward. The content of this dissertation is improving energy efficiency by interference alignment method in multi-user MIMO systems.Firstly, this dissertation describes the implement of interference alignment in multi-user MIMO system. Simulations for three classical algorithms-- minimum interference leakage, minimum mean square error and maximize signal to interference and noise ratios verifie the validity of interference alignment. Then proposes two optimization algorithms-- joint optimization algorithm and orthogonal maximize signal to interference and noise ratios algorithm. Simulations show that two optimization algorithms outperform the classical algorithms.Sencondly, consider the situation that can not get accurate channel state information which means estimation error exists, how channel estimation error effects the above algorithms. Analyze the influences of number of users, computational complexity and convergence speed for each algorithm. Combine the above analysis found that: despite the slight increase in computational complexity, orthogonal maximize signal to interference and noise ratios algorithm has a significant advantage in terms of improving system sumrate and a relatively smaller influence by the estimation error.Finally, establish the system power consumption model and analyze energy consumption of each part in the system. Put forward the definition of energy efficiency and energy efficiency optimization algorithm based on orthogonal maximize signal to interference and noise ratios algorithm.