Robust Transceiver Design for Multicell MIMO Downlink Systems

The robust linear transceiver design for the more general model of multicell MIMO downlink system with imperfect channel state information is discussed in this paper. Our aim is to minimize the total power of the network while the quality of service (QoS) in terms of mean-square error (MSE) for every user should be strictly guaranteed for every channel realization in the uncertain region. Unfortunately, this problem may be infeasible due to the MSE constraints. Therefore, we provide a complete analysis of this problem by dividing the solutions into two phases. In phase I, a novel approach is devised to check the feasibility of this problem by considering one alternative problem which is always feasible. This alternative problem is troublesome due to infinite nonconvex MSE constraints. To handle this, we propose an iterative algorithm that performs optimization alternatively by switching between the precoders and decoders. The two subproblems in the algorithm can be recast as semidefinite programming problems which can be efficiently solved. In phase II, one novel iterative algorithm is proposed to solve the original robust problem. Finally, simulation results show that our proposed algorithms converge rapidly and can provide guaranteed QoS for all users. Moreover, we also show that, the more antennas at the users, the more power savings it can provide.