Multi-path routing In Cognitive Radio Networks for multimedia communication using sample division multiplexing

We propose a novel scheme for multi-path routing in a Cognitive Radio Network (CRN) for multimedia communication, even when a contiguous band of required width is not available for any hop in the route. The proposed scheme is based on an extension of the idea of Sample Division Multiplexing (SDM) as given in [1] for single-hop communication. Starting from the source node, we first explore the available (free) number of channels (not necessarily contiguous) between every pair of 1-distance neighbor nodes by the help of appropriate control messages. With the information gathered from this step, the network graph G is constructed. We run the max-flow algorithm [8] on this network graph to find the set of routes between the source and the destination nodes so that the sum total of the usable numbers of channels through all these routes is equal to the required number of channels for the multimedia signal to be communicated. In essence, each data packet of the multimedia signal is split into several sub-packets following the basic concept given in [1] each of which needs much smaller bandwidth than the original packet, and these sub-packets are sent through all these routes to be eventually received by the destination node with the desired QoS. The time complexity of our proposed algorithm for this route discovery is O(pf + T_SD), where p is the number of edges in the network graph (G), f is the maximum flow in G and T_SD is the initialization time for constructing the network graph. We have shown that T_SD is O(Δδ_max), where Δ is the diameter and δ_max is the maximum node degree of the network graph.