Asymptotic Performance of Two-User Interference Channels Using Coordinated Zero-Forcing

This letter studies the performance of the zero-forcing (ZF) coordinated transmission strategy in multiple-input multiple-output (MIMO) interference channels, by examining the asymptotic behavior of the metrics such as sum-rate and outage probability in the large-system regime where the dimensions of the MIMO channel go to infinity. Using random matrix theory, we propose an asymptotic estimate of all the eigenvalues of the effective channel matrix of the coordinated ZF strategy and then derive closed-form expressions of the sum-rate, from which the scaling law of the sum-rate against the MIMO dimension is illustrated. Using multivariate statistics on the probability density distribution (pdf) of the minimum eigenvalue of a Wishart matrix, an analytical expression of the outage probability for the coordinated transmission is then obtained under two special cases. Simulation results demonstrate that our proposed analytical expression is valid not only in the large-system regime, but also in the scenario where the numbers of antennas are small.