WLC11-4: Power Control for Cellular MIMO Systems

Power control is an important technique for interference management in interference-limited multiuser communication systems. In this paper, we propose a novel multidimensional power control technique for the uplink of cellular MIMO systems. Similar to prior single antenna power control work, we employ a fixed SINR target that allows guaranteed quality-of-service for delay-sensitive data applications. The proposed power control scheme is a more general technique because it incorporates single antenna, orthogonal multi-carrier, and utility-based power control schemes as special cases. Two approaches are proposed, the first where each user´s power is equally allocated to its antenna array, in the second the allocation is adaptive. The optimal solution with full channel knowledge, and a practical near-optimal solution requiring only partial channel knowledge, are both derived. Numerical results show that power control actually achieves higher throughput a.t the low SINRs typical in cellular systems, compared to supposedly optimal water-filling strategies, with lower overhead and complexity. In the higher SINR ranges, iterative water-filling indeed slightly outperforms adaptive power allocation. Due to its better exploitation of spatial diversity and reduced transmit power (and hence reduced other-cell interference), adaptive power allocation increases the achievable SINR by an order of magnitude over equal power allocation, resulting in far better coverage.