Tensor-based blind asynchronous cooperative diversity receiver

The distributed nature of cooperative networks may result in asynchronous received signals, which overshadows the diversity gains promised by cooperative communications. In this paper we propose a new blind cooperative diversity receiver, which ensures the gains of cooperative transmission diversity with a large delay. In the proposed scheme, multiple asynchronous signals are reconstructed at the receiver by Canonical Polyadic (CP) decomposition for tensor modeling, associated with arrival angles of the signals, channel gains and signals. The tensor-based receiver can operate without timing synchronization or orthogonal channelization between relays and does not require any pilot symbols as well. The numerical simulation results show that the bit error rate (BER) of the proposed scheme is better than that of synchronous Alamouti code and minimal loss is comparable with the orthogonal transmission scheme with no delay. We also conclude that the BER performance and convergence speed of the scheme can be improved using the optimum to initialize ALS iterations.