Abstract: The capacity region with average power constraints of MIMO fading multi-access channels based on minimum rate requirements is analyzed and the optimal power allocation strategy is suggested.The strategy is a two-step process, the allocation of the minimum power required to achieve the minimum rates and the optimal allocation of the excess power to maximize the ergodic rates.It is shown the minimum-rate capacity can be achieved by successive decoding.The numerical results show that, the strategy provides notable capacity gain and good tradeoff in performance.

Key words: multi-access channel, MIMO, minimum-rate capacity, power allocation