A Family of Quasi-Orthogonal Space-Time Block Codes with Linear Receivers

In this paper, we explored the potential of using linear receivers for one of the best existing space-time block codes (STBCs) namely Quasi-orthogonal STBCs (QOSTBCs). This family of QOSTBCs are known as one of the best, because of their good performance, systematic construction for any number of transmit and receive antennas and appropriate symbol rate. The only disadvantage of these codes could be the complexity of their maximum likelihood (ML) decoder. In this paper, we used linear receivers to reduce the complexity of the receiver. In both well-known linear receivers namely minimum mean square error (MMSE) decoder and Zero-forcing (ZF) decoder, the receiver needs to compute the inverse of the equivalent channel matrix which adds the burden of calculating the high computational complexity operation of matrix inverse. In this work, more importantly, we could formulate the general form of the inverse of the equivalent channel matrix which extremely decreases the computational complexity of the receiver.