Cooperative MAC relaying with multi-rate transmissions and network coding

In the literature, cooperative relaying and network coding have been used separately in improving performance of wireless MAC protocols. In this paper, we propose a novel scheme that combines both cooperative relaying and network coding for further performance improvement. The proposed scheme considers two challenges of network-coded cooperative MAC operating in a realistic wireless network. First, links in realistic networks inherently operate with different data rates due to varying channel conditions and distances between the nodes. Existing works do not consider this issue and consequently the coding advantage is not fully harnessed. In our proposed scheme, we integrate both network coding and multi-rate issues as a single optimization problem. Second, network coding used in existing works require costly and reliable feedback in order to harness the gain. Since realistic links are unreliable in nature, our proposed scheme uses a cyclic coding method instead of the traditional XOR coding. Our results show that the proposed scheme can achieve a gain that is two times greater than a non-cooperative scheme.