Analysis and results for H-MIMO - a hybrid of spatial multiplexing and adaptive beamforming

The use of multiple antennas at both ends of a wireless link can provide substantial increases in capacity. In MIMO systems, the multiple antennas could be utilized in different ways to maximize performance in a particular environment. In F.R. Farrokhi et al. 2002, a spatial multiplexing system was compared with a system that uses multiple antennas to perform adaptive beamforming. In this paper, we evaluate the performance of a hybrid MIMO (H-MIMO) system where the antennas are used in a combination of these two modes. Through simulations, we show that, over a wide range of target outages and Ricean K factors, the hybrid systems can achieve higher efficiencies for users who are farther from the base station or, alternatively, can provide higher capacities to a larger percentage of users in a cell