Semi-analytic Performance of a Multiaccess MIMO Scheme Using Precoding Vectors

This paper addresses the problem of transmitting data to multiple mobile stations using a decode-and-forward strategy. Precoding vectors are used in relays to cancel out multiple access interference at the mobile stations. The diversity gain of the system has been analytically calculated for the case of two mobile stations. The system performance for arbitrary number of mobile stations is calculated using a semi analytic approach. In this approach the distribution of signal to noise ratio is approximated by a mixture of Nakagami laws using an Expectation-Maximization algorithm. Then the symbol error probability of this mixture is analytically calculated. Simulations confirm the theoretical results showing that the full diversity advantage can be obtained, which is the product of the number of antennas at each relay by the number of relays minus the total number of system constraints.