Direction of arrival and capacity characteristics of an experimental broadband mobile MIMO-OFDM system

This paper describes a series of field experiments that were performed in order to evaluate direction-of-arrival (DOA) and capacity characteristics of a 18.8 MHz 2×2 MIMO-OFDM channel at 3.676 GHz. These experiments were conducted in a suburban setting outside Chicago, Illinois with an experimental mobile broadband MIMO-OFDM system. We present multipath DOA statistics calculated based on a synthetic aperture array technique. This technique operates on data snapshots collected while the receiver was moving and makes use of the velocity and direction information provided by a GPS receiver. We also present MIMO capacity statistics that are computed from the frequency-domain matrix channel response measured by the experimental OFDM system. To explore the effect of frequency and receive angular diversity on the MIMO capacity distribution, we present cumulative distribution functions of the capacity gain of a 2×2 link (i.e., gain relative to 1×1 link) for different measured delay spread ranges as well as different DOA spread ranges.