Uncoordinated Distributed Space-Time Trellis Coding

In this paper, we introduce a new class of distributed space-time trellis codes (DSTTCs) for wireless networks with a large set of decode-and-forward relay nodes N. It is assumed that at any given time only a small, a priori unknown subset of nodes S - N is active. We consider the general case where each relay node is equipped with NT antennas and the destination node has NR antennas. In the novel distributed space-time trellis coding scheme each relay node is assigned a unique signature matrix but all active nodes use the same trellis for encoding. Efficient methods for the optimization of the set of signature matrices are provided and it is shown that existing full-rank STTCs designed for Nc - 2 co-located antennas are a favorable choice for the trelis encoding. If properly designed, the proposed DSTTCs achieve a diversity order of d = min{NcNR, NTNSNR} if NS nodes are active. Simulation results show the superior performance of the novel DSTTCs compared to distributed space-time filtering and distributed space-time block coding.