A Hybrid Dynamic QRDM and ZF Detection Algorithm for MIMO-OFDM Systems

Abstract—An effective signal detection algorithm with low complexity is presented for MIMO-OFDM systems. The proposed technique combines a dynamic QR decomposition based M-Algorithm (QRDM) and Zero-Forcing (ZF) detection. In the systems, QRDM is executed for the first / 3 1T TN N − + ⎡ ⎤ ⎢ ⎥ layers, ZF detection is used for the last / 3 1TN − ⎡ ⎤ ⎢ ⎥ layers, where TN means the number of transmitter antennas. Compared with the conventional QRDM algorithm, this approach is simple and has low complexity because not all branches are searched. Furthermore, the performance of this algorithm is similar to that of the conventional QRDM algorithm. The receiver detection simulation is based on five paths Rayleigh fading environment without channel coding, assuming the channel matrix H is perfectly known by the detector. From simulation results, the complexity of QRDM-ZF detection algorithm for 4 transmitter antennas and 4 receiver antennas systems with quadra-binary-shift-keying (QBSK) modulation is reduced by 29.41 % on average and it is reduced by 30.08 % on average for 16-quadra-amplitude-modulation (QAM). The performance degradation is about 2dB at BER=10-3.The proposed hybrid QRDM-ZF detection can be used for a MIMO-OFDM receiver requiring not very high performance but needing very low complexity. Keywords-MIMO-OFDM;QR-decomposition;Zero-Forcing; QRDM algorithm; QRDM-ZF algorithm. I