MIMO OFDM signal detection using quadratic programming

In this paper we present a novel optimization scheme based on quadratic programming (QP) for solving Maximum Likelihood Decoding (MLD) problem in Multiple Input Multiple Output (MIMO) Orthogonal Frequency Division Multiplexing (OFDM) signal detection systems. Though the MLD method gives the most optimum mathematical solution for detecting multiple signals at the MIMO receiver, but it is hard to implement because of its high computational complexity, that grows exponentially as the number of transmit antennas or the modulation order is increased. The proposed method has extremely low computational complexity as compared to that of the MLD scheme. The proposed method has also been compared with the Zero Forcing (ZF) method which is the simplest method but has high bit error rates. Overall the QP method offers a good tradeoff between high computational complexity (of MLD) and low error performance (of ZF) for a MIMO OFDM receiver.