Delay-Tolerant Distributed Linear Convolutional Space-Time Code Under Frequency-Selective Channels

In cooperative communication networks, the performance of the distributed space-time code (DSTC) will be severely degraded if the timing synchronization among relay nodes are not perfect. In this paper, we propose a systematic construction of the so called distributed linear convolutional space-time code (DLCSTC) for multipath fading channels that does not require the synchronization assumption. We derive sufficient conditions on the code design such that the full cooperative and multipath diversities can be achieved under the minimum memory length constraint. Then we design DLCSTCs that both have the trace-orthonormality property and achieve the full diversity. We also study the diversity property of the DLCSTC with suboptimal receivers. We show that the proposed codes can also achieve the full diversity for asynchronous cooperative communications with ZF, MMSE and MMSE-DFE receivers under frequency-selective channels. Finally, various numerical examples are provided to corroborate the analytical studies.