New user coexistence with network under interference alignment

Recent results find numerical scheme for interference alignment (IA) to approach the Shannon capacity in interference network. In this paper, a constant multiple input multiple output interference channels where a group of user-pairs are communicating with each other through interference alignment while a group of new user-pairs desire to access the same channel. The primary users will not be affected when the new arrival users have enough transmit antennas that can null the interference from the new users at primary receiver. When a group of arrival users can not affect the primary user, we analyze the performance of sum rate while the new users use iterative algorithm to eliminate the interference from primary users. The iterative algorithm can make the new users network communicate without interference at the same time.