Multimedia transmission over cognitive radio networks using decode-and-forward multi-relays and rateless coding

Recently, cooperative communications are emerging as a new paradigm in cognitive radio networks, as they help to deliver the multimedia data between cognitive users over large distance. In this paper, we introduce a novel dual-hop multi-relay cooperative scheme relying on the concept of Cognitive Radio for Virtual Unlicensed Spectrum (CORVUS). The multimedia stream is distributed over the two hops using fountain codes and secondary links are established using the CORVUS approach. In particular, the source node broadcasts the encoded stream to a set of relaying nodes, each will be responsible of conveying different packets from the same fountain to the common destination. The proposed scheme avoids the need for coordination among the cognitive relays and prevent the destination receiving duplicated packets. Numerical simulations are performed in terms of the average transmission time and the end-to-end throughput to prove the effectiveness of the proposed solution in dealing with dynamics between primary and secondary users in addition to sub-channel impairments.