Enhanced selection combining for compact single RF user terminals in multiuser diversity systems

The downlink performance of systems exploiting multiuser diversity has been shown to improve by using multiple antenna receivers and diversity combining techniques. However, the cost and power restrictions of the user mobile terminals prohibit the use of multiple antennas whereas the size limitations can result in correlated and coupled receive antenna elements downgrading the effectiveness of the applied schemes. In this paper, we propose a simple beam selection combining (SC) technique using a miniaturized single radio receive antenna system assisted by low cost parasitic antennas. The system is optimized for both antenna efficiency and diversity thus made capable of forming four practically uncorrelated beam-patterns. The computer simulations show that the proposed beam SC technique outperforms classical antenna SC as well as a previously reported beam combining approach in terms of the average throughput especially for small user populations.