Enhanced cooperative coding for relay-based MIMO-OFDM systems

In this paper, we propose a 2 × 2 cooperative multiple-input multiple-output (MIMO) orthogonal frequency-division multiplexing (OFDM) scheme based on Alamouti space-time coding. In this scheme, the the relay and the destination antennas receive the transmitted symbols from the source during the first stage. Then, both the relay and the destination generate their own decision variables using an Alamouti decoding procedure by the end of the first stage. In the second stage, the relay sends its own decision variables to the destination to enhance the destination decision variables and therefore improves the performance of the system. Our results show the superiority of the proposed cooperative Alamouti scheme by improving the system performance in terms of average BER, frame error rate (FER), and spectral efficiency.