Coalition-Based Cooperative Routing in Cognitive Radio Networks

Abstract

Cooperative relaying in cognitive radio networks offers time and space diversity and thereby, provides an effective technique to improve spectrum utilization. Most of the existing research has been focused on adopting this technique in single hop communication which may not fully exploit the benefits of cooperative transmissions. Recently, multi-hop cooperative relaying has been explored in routing path formation between primary transmitter-receiver pairs. In this approach, each user handles one cooperation request at a time and takes part in at most one routing path, which makes the model unscalable and limits the benefits of cooperation. Also, primary users dictate the cooperation terms with no or limited involvement from the participating secondary users. This model, therefore, cannot capture the dynamics when both the primary and secondary users require to make cooperation decisions considering the tradeoffs of multiple offers. As a result, the essence of multi-hop cooperative relaying cannot be realized from the existing approach and calls for further investigation. In this work, we consider a network of coexisting primary and secondary users in which their intention to improve throughput via mutual cooperation is formulated as an overlapping coalition formation game. Based on the analysis of the game, we devise mcRoute, a distributed multi-hop coalition based cooperative routing and scheduling algorithm that forms stable coalitions satisfying users' mutual interest. A primary user constructs its routing path in the form of a coalition with secondary users relaying its packet. A secondary user takes part in one or more coalitions by relaying corresponding primary packets and accessing their channels for its own transmission. Finally, we analyze the performance of the algorithm through extensive numerical simulations.