Area Coverage of a Multi-Link MIMO System with Water Filling Power Allocation Strategy

Abstract

In this paper, we propose a power allocation of multi-link MIMO system. The multi-link MIMO system transmits different signals to a mobile station by using plural base stations with multiple antennas. The system improves not only area coverage but also spectrum efficiency. Here water filling power allocation strategy is used to optimize the capacity of the multi-link MIMO channel. This paper focuses on the downlink channel and presents single-user performance of the system. The performance is evaluated by area coverage that is, the percentage of the locations where the capacity exceeds the target value. The presence of Rayleigh fading, shadow fading, and path loss is assumed in this paper. Our numerical results showed that the area coverage of the multi-link MIMO systems with equal power allocation was greatly improved compared with that of conventional single-link MIMO systems. However, when the capacity of MIMO channel was optimized by water filling power allocation strategy, the performance improvement with multi-link was reduced compared with that of using equal power allocation. In the case of (3,1) and (6, 3) MIMO systems, there were regions that single-link MIMO outperformed multi-link MIMO systems.