A capacity measure for space-division-multiple-access channels

Space division-multiple-access (SDMA) systems which exploit the spatial diversity among different users has been shown to be effective in solving some key problems in wireless communication systems. We look at the exploitation of such spatial diversity for capacity increase from a fundamental point of view, i.e., the minimum Euclidean distance of the constellation for SDMA channels. Using the minimum distance measure, we strive to quantify the performance enhancement of the SDMA approach including capacity increase and quality improvement. In particular we evaluate the minimum distance of SDMA channels in different scenarios, i.e., different number of antennas, constellation and relative user positions.