Multi-User MIMO Downlink Channel Capacity for 4G Wireless Communication Systems

This paper investigates the performance of multiple-input multiple-out (MIMO) wireless communication systems in a multiuser environment. The user information is defined by a data matrix generated by the observed input-output data of the system, from which subspace identification method is developed using LQ-decomposition of the matrix. The LQ-decomposition is basically used to solve for the user transmitted signals from a mobile station to the base station. Then the relation between the data matrix and the channel information based is derived using singular value decomposition (SVD) algorithm. The effect of additive white noise due to the wireless channel on the SVD of a rectangular matrix is considered to estimate channel capacity of a MIMO system in multi-user environment. Simulation results are then presented to evaluate the performance of the MIMO system in terms of channel capacity, which illustrate that multi-user MIMO systems have good channel capacity.