Performance limits of rateless codes in delay constrained multihop relay networks

Rateless code properties ideally suit multi-node transmissions with decode-and-forward based relaying strategy, and have been extensively employed in delay tolerant networks. The overall latency suffered by such networks forces to conserve the end-to-end delay, especially for real-time applications, by limiting the number of rateless coded transmissions. However, the performance of rateless codes deteriorates in such circumstances due to the lack of sufficient mutual information for successfully recovering the entire source packets. This performance degradation can be gauged by the average packet recovery and cooperation among nodes results in enhanced performance. The exact closed-form equations for the average packets retrieved based on the channel usage for such delay constrained networks (DCNs) is derived in this paper. These are verified and supported with results from extensive simulation studies.