Performance Analysis of a QR Decomposition Algorithm Employing Rearrangement of Antenna Layers on V-BLAST Systems

Abstract

In a Rayleigh fading environment, the paper firstly introduces system model and the vertical Bell laboratories layered space-time (V-BLAST) systems structure. Several popular decoding algorithms for V-BLAST are carried on the analysis comparison, such as zero-foring (ZF), minimum mean squared error (MMSE), QR decomposition, and maximum likelihood (ML) etc. On this basis, the paper focuses on QR decomposition research, analyzes and summarizes the QR decomposition algorithm and iterative algorithm. We draw a conclusion that the key of improving QR scheme performance is to choose the upper triangular matrix R. From intuitionistic point of view, three selection criterions are given, such as rearrangeing matrix H according to row vectors, the maximum element r(Nt, Nt) of the matrix R, and the maximum diagonal squared Frobenius norms (SFN) in R. The simulation results indicate that the selection rule of the maximum r(Nt, Nt) can obviously improve the performance of the first decoded layer. For a 4Tx4Rx MIMO V-BALST system, the simulation results show that the V-BALST system performance is to be improved further when we combined the maximum r(4,4) criterion with the iterative algorithm.