Joint user pairing and power allocation in uplink virtual MIMO with imperfect CSI

User pairing strategy for virtual multi-input multi-output (VMIMO) has been widely studied to improve system throughput, but most studies are based on perfect channel state information (CSI) and uniform power allocation. However, perfect CSI is very difficult or even impossible to obtain in practical system. Moreover power allocation has significant impact on algorithm performance. Therefore, in this paper, a low-complex joint user pairing and power allocation algorithm based on aggressive discrete stochastic optimization and Lagrangian dual solution is proposed for uplink VMIMO with imperfect CSI. Simulation results show that the proposed algorithm can achieve desirable throughput performance, and restrict inter-user interference (IUI) efficiently.