Cooperative space-frequency coding for broadband relay channels

In this paper, a new distributed space-frequency coding (DSFC) scheme, for broadband fading relay channels is presented. This scheme exhibits a spatial and a multipath diversity in a distributed fashion. An upper-bound on the pairwise error probability (PEP) is derived. From this PEP bound, it is shown that the proposed coding scheme achieves a diversity of order NL , where N is the number of relay nodes and L is the channel memory length. A decode-and-forward (DAF) protocol and erroneous decoding at the relay nodes are considered. To compensate for the diversity loss due to potential error detection at the relay nodes, additional coding at the source node is proposed.