Orthogonality-Based User and Receive Antenna Selection for MIMO Broadcast Channels

In MIMO broadcast channels, the Block Diagonalization (BD) transmit precoding performs better than the Zero-Forcing (ZF) transmit precoding when the user equipment has multiple receive antennas and can support multiple data streams. The number of users simultaneously supported by BD is much less than the total number of users in the system, so selecting proper users and/or receive antennas is important to achieve high overall sum capacity. So far, the capacity-based and norm-based user and receive antenna selection algorithms are proposed, which are greedy based and have much lower complexity than the brute-force based algorithms. In this paper, the orthogonality-based user and receive antenna selection algorithms are employed. The idea of the algorithm is simple, however, we show by detailed complexity analysis and extensive simulations that the orthogonality-based user and receive antenna selection achieves much better complexity and performance tradeoff than the existing capacity-based and norm-based algorithms. So, the orthogonality-based algorithms are more attractive for practical MIMO broadcast systems.