Reducing the channel estimation error for relay networks with cyclic delay diversity

In this paper we study an amplify-and-forward broadband relay network with cyclic delay diversity. Our main focus resides in reducing the channel estimation error by exploiting the cyclic shift and the properties of the fast Fourier transformation (FFT). Besides the improvement cyclic delay diversity is already delivering at almost no cost at the relays, we show that the bit error rate can be reduced. Furthermore, we investigate channel estimation at the destination and compare the results from scenarios with perfect channel knowledge. It is shown that the performance of the proposed noise reduced channel estimation for a relay network with and without cyclic delay diversity strongly depends on the frequency selectivity of the channels.