Spectrum map aided multi-channel multi-hop routing in distributed cognitive radio networks

In this paper, we propose a spectrum map aided routing protocol for a distributed cognitive radio network. We assume the presence of dedicated sensors that capture the spatio-temporal spectrum usage statistics to create the radio environment map. We exploit the map to find not only the best hops along a route but also the best available channel in terms of the expected performance. Through the use of edge nodes, which lie in the intersection of more than one sensors´ domain, inter-domain routing is facilitated. The selection of each hop, the channel to be used per hop, and the transmitting power to be used considers i) protection of primary receivers, and ii) maximization of desired performance metric. In this context, we propose a novel power control mechanism that computes just enough power to maintain the desired signal-to-noise ratio for secondary communication but at the same time protects the primary receivers in the vicinity. We analyze and compute the probability of network connectivity by finding the minimum spanning tree of the graph formed by the over-lapping domains. Through simulations, we show how the proposed routing scheme works in terms of route capacity, connectivity of the network, reachability among the nodes, and number of primary receivers protected.