A frequency domain differential modulation scheme for asynchronous amplify-and-forward relay networks

In this paper, we investigate cyclic prefixed single carrier block transmission for asynchronous wireless relay networks. To avoid channel estimation at the receiver, a simple frequency-domain differential encoding and decoding scheme is proposed for asynchronous relaying. Specifically, a block-by-block frequency domain differential encoder is employed at the source node, while joint frequency domain differential decoding and equalization is developed at the destination to recover the information symbols. Numerical results are presented to demonstrate the bit-error-rate (BER) performance of the proposed scheme. It is shown that the proposed cyclic prefixed frequency domain differential transmission scheme is robust to asynchronous delays and Doppler frequency shifts.