Opportunistic maximum rate user selection with low complexity in MIMO interference channel

In this paper, we propose two low-complexity opportunistic user selection schemes in multiple-input multiple-output interference channels (MIMO ICs). First, an opportunistic maximum rate user selection (OMRUS) scheme is proposed. In the OMRUS scheme, a new criterion for user selection which simply approximates the maximum rate of each user is introduced, and by using the proposed selection criterion we achieve as good sum-rate as the conventional schemes with considerably low computational complexity. The OMRUS scheme also has the advantage of extendibility to any number of multiuser ICs though the conventional opportunistic interference aligned user selection (OIAUS) cannot be directly extended to more than three-user case. Second, a modified OIAUS is proposed to improve the sum-rate of the conventional one by modifying the OIAUS criterion to reflect the effects of both the desired signal power and the degree of interference alignment. Mathematical and numerical results show that the proposed user selection schemes both have low computational complexity, which is comparable with the conventional OIAUS, and improve the sum-rate compared with the conventional ones.