Complexity Reduction in ML Decoding For MIMO Systems

In this paper, we propose a combined Breadth first tree search ML (Maximum Likelihood)-ZF (Zero Forcing) method of detection for Spatial Multiplexed MIMO (Multiple Input Multiple Output) systems with reduced complexity. The detection of real and imaginary parts of QAM (Quadrature Amplitude Modulation) modulated symbol is carried out in successive level of tree which makes parallel processing possible. Reduction in complexity compared to conventional ML for a 2x2 system is 80% and for a 4x4 system is 83%.