Closed-form expression for the optimum antennas number of a spread spectrum MIMO system under rayleigh fading conditions

In this presented work, the problem of selecting the number of antennas for a spread spectrum multipleinput multiple-output (MIMO) cellular system is investigated, in order to maximize the Shannon’s channel capacity (estimated in average sense) assigned to each system’s user when operating in a Rayleigh fading environment. Then, the spectral efficiency is estimated in terms of the achievable average channel capacity per user, during the operation over a broadcast time-varying link, and leads to a simple novel-closed form expression for the optimum number of transmitting antennas value based on the maximization of the achieved average channel capacity per system’s user. Key-words: -MIMO systems, channel capacity, cellular systems, Rayleigh fading.