Space-Time Two Dimensional RAKE Receiver in Cooperative Communications Systems with Interference Cancellation Technique

In this paper, space-time two dimensional RAKE receiver was introduced into the asynchronous cooperative communication systems, and a high-performance RAKE receiving algorithm was proposed. Firstly, the transmitted signal was estimated by traditional space-time RAKE receiver, and then, decision feedback technique was investigated into the new algorithm, where each multipath component in the received signal was composed using the estimated results of the transmitted signal and then cancelled successively from the received signal, so the inter symbol interference in the received signal which was generated by the multipath fading channel was eliminated, and the line of sight (LOS) component in the received signal was obtained. Finally, the LOS component was combined together by the space-time block code combining rule to obtain the spatial diversity gain. Based on that, the iterative decision feedback architecture was further employed, where one stage stands for the process from multipath components reconstitution to space time combination, and the performance of the new scheme can be improved effectively by the multiple decision feedback stages. Computer simulations show that the new algorithm can improve the performance of traditional space-time RAKE dramatically when SNR is higher than 5 dB in asynchronous cooperative communication systems.