Optimal Weighted Antenna Selection for Imperfect Channel Knowledge from Training

Receive antenna selection (AS) reduces the hardware complexity of multi-antenna receivers by dynamically connecting an instantaneously best antenna element to the available radio frequency (RF) chain. Due to the hardware constraints, the channels at various antenna elements have to be sounded sequentially to obtain estimates that are required for selecting the "best" antenna and for coherently demodulating data. Consequently, the channel state information at different antennas is outdated by different amounts. We show that, for this reason, simply selecting the antenna with the highest estimated channel gain is not optimum. Rather, the channel estimates of different antennas should be weighted differently, depending on the training scheme. We derive closed-form expressions for the symbol error probability (SEP) of AS for MPSK and MOAM in time-varying Rayleigh fading channels for arbitrary selection weights, and validate them with simulations. We then derive an explicit formu...

• Type: Journal
• Year: 2009
• Where: ICC
• Authors: Vinod Kristem, Neelesh B. Mehta, Andreas F. Molisch
• Keywords: Antenna Elements, Communications, Electric Research Laboratories, ICC 2009, Mitsubishi Electric Research