Abstract:

Antenna subset selection can greatly reduce the implementation complexity of multiple input multiple output (MIMO) systems while retaining most of their benefits. This paper investigates the diversity gain and capacity of such systems in wireless personal area networks. Considered scenarios include both the communication between access point to a laptop, and between two hand held devices. We analyze the performance of different antenna selection algorithms and signal combining methods in measured dual-polarized narrow band and wide band propagation channels. We find that line-of-sight and non-line-of-sight situations have fairly similar behavior. Different polarizations result in similar signal-to-noise ratio gains when the multiple antennas are used for diversity, but result in noticeably different capacities in spatial-multiplexing systems. We also find that radio frequency (RF) preprocessing of the signals is less effective for hand held handsets with non-uniform antenna arrangements than for uniform linear arrays. For communications between hand held devices, simple selection (of one out of four antennas) shows extremely high performance gains compared to no-selection. Finally, we compare bulk selection (same antenna subset is used for all frequency sub-channels) to per-tone selection (different antenna subsets can be used for each frequency sub-channel) for wide band channels. Bulk selection together with RF preprocessing performs almost a s well as per-tone selection for some scenarios.