Switching transmission mode in multiuser-MIMO systems

The developing fifth generation (5G) wireless networks are prepared to support the fundamental challenges, for example, very high data rate application, power control and high spectrum efficiency. To achieve these requirements, Multiuser Multiple-Input Multiple-Output (MU-MIMO) systems is the attractive option to increase both data rate and spectrum efficiency in uplink channel. In this paper, switching between spatial multiplexing (SM) and transmit diversity (TD) is proposed to increase the diversity performance in MU-MIMO systems. In this technique, the different transmission modes can be chosen for each user based on the instantaneous channel state at the receiver. Monte Carlo simulations validate advantage of the proposed technique over either spatial multiplexing or hybrid-MIMO technique in term of symbol error rate.