Adaptive joint multi-cell reception with uplink power control and beamforming

Assuming that multiple base stations (BSs) are coordinated for the joint reception of each user's transmitted signal in the uplink, we study the sum power minimization (SP-MIN) problem for the cellular systems. As BSs may have multiple antennas, power control and receive beamforming are jointly optimized with the adaptive multi BS set (MBS) selection for each user. By doing optimization iteratively, an algorithm is proposed to find the minimum transmit power. Although the SP-Min problem is non-convex in general, it is proven that the proposed algorithm using the optimal MBS selection can converge to the optimal solution as long as it is feasible. To improve the computational efficiency of the algorithm, two simplified MBS selection schemes have been presented as well as the optimal scheme. Using the proposed algorithm with either the optimal or the simplified MBS selection schemes, a significant power efficiency improvement is obtained which is verified by the system level simulations.