Precoding Design for Coordinated Multicast and Unicast Transmission in C-V2V Massive MIMO With Imperfect CSI

In this paper, we study the coordinated multicast and unicast transmission for cellular-based vehicle-to-vehicle (C-V2V) massive multiple-input multiple-output (MIMO) in the scenario where only imperfect channel state information is available at the base station side and the transmitter in each V2V communication pair. The precoding design problem is a weighted ergodic sum-rate maximization problem with the imperfect CSI including channel mean and variance information known, and the objective function is the weighted sum of the achievable ergodic unicast rate for all the V2V pairs and the achievable ergodic multicast rate for all the cellular users. The minimize-maximize (MM) algorithm and the deterministic equivalent method are utilized to solve the problem and reduce the computational complexity. The simulation results demonstrate the significant improvements of the proposed coordinated communication method in the system spectral efficiency.