Asymptotic Analysis of the Performance of LAS Algorithm for Large MIMO Detection

X iv :0 80 6. 25 33 v2 [ cs .I T ] 3 1 O ct 2 00 9 Asymptotic Analysis of the Performance of LAS Algorithm for Large-MIMO Detection∗ Saif K. Mohammed, A. Chockalingam, and B. Sundar Rajan Department of ECE, Indian Institute of Science, Bangalore 560012, India Abstract In our recent work, we reported an exhaustive study on the simulated bit error rate (BER) performance of a low-complexity likelihood ascent search (LAS) algorithm for detection in large multiple-input multiple-output (MIMO) systems with large number of antennas that achieve high spectral efficiencies. Though the algorithm was shown to achieve increasingly closer to near maximum-likelihood (ML) performance through simulations, no BER analysis was reported. Here, we extend our work on LAS and report an asymptotic BER analysis of the LAS algorithm in the large system limit, where Nt, Nr → ∞ with Nt = Nr, where Nt and Nr are the number of transmit and receive antennas. We prove that the error performance of the LAS detector in V-BLAST with 4-QAM in i.i.d. Rayleigh fading converges to that of the ML detector as Nt, Nr → ∞.