Spectrum-Efficient Resource Allocation Framework for Cooperative Opportunistic Wireless Networks

Dynamic spectrum access (DSA) is a promising approach to alleviate spectrum scarcity and improve spectrum utilization. Recently, several cooperative communication schemes have been proposed to further enhance spectrum utilization in DSA networks. Existing cooperation designs are either tailored for primary-secondary user (PU-SU) cooperation and not applicable to SU cooperation, or focus on the potential benefits of SUs cooperation without investigating how SUs agree on cooperating and the conditions that lead to improve their performance. In this paper, we introduce a spectrum-efficient resource allocation framework based on SUs cooperation, where the resources include the free spectrum access time, available channels, and relays. First, we formulate the interactions between the cooperating SUs and a PU using a discrete-time Markov chain (DTMC). Using this DTMC and Nash bargaining, we determine the new spectrum access times for SUs based on every nodes utility. We also derive the conditions under which all SUs improve their performance by cooperation. Second, considering a multi-channel multi-SU infrastructure network, we formulate two optimization problems for jointly allocating channels to SUs and selecting the cooperating SU pairs. We corroborate our analytical findings with detailed simulations that evaluate SUs cooperation gains and the optimality of the proposed joint allocation schemes.