Characterization of DOD and DOA correlation among converging indoor radio links by applying reciprocity principle

Many works on single link multi antenna channel characterization have been reported and adopted as parts of standardized channel model. In this paper we report the characterization of converging multi-antenna channels, particularly the correlations of direction of departure (DODs) and direction of arrivals (DOAs) of multipath component signals (MPCs) in two scenarios, first, multiple radio links between one transmitter and several receivers, and second, between several transmitters and one receiver, both in indoor non line of sight (NLOS) environment. We argue that DOD and DOA correlation of the second situation are identical to the first one according to the reciprocity principle of the channel. Through measurements we show that this channel reciprocity principle is well confirmed. We have conducted a set of measurement of the first situation described above to characterize the DOD and DOA correlation and propose curtailed Gaussian for statistical model of their distribution.