Linear dispersion codes design for asynchronous cooperative communications

In this paper, we study the design of linear dispersion codes (LDCs) for asynchronous cooperative communication networks. Firstly, the concept of conventional LDCs is extended to the delay-tolerant version and new design criteria are discussed. Then we propose a new design method to yield delay-tolerant LDCs that approach near-optimal capacity as well as minimum average pairwise error probability. The proposed design employs stochastic gradient algorithm to guarantee the local optimum. Moreover, it is improved by using simulated annealing type optimization to approach the global optimum. The proposed method allows flexible number of nodes, receive antennas, the length of codewords and the number of modulated symbols. Simulation results confirm the performance of the newly-proposed delay-tolerant LDCs.