Utility-based Decision-making for Symbiotic Cooperative Relaying in Cognitive Radio Networks

A recent paradigm in the research surrounding Cognitive Radio (CR), is a Symbiotic Cooperative Relaying architecture, which improves the efficiency of spectrum usage and reliability of the transmission links. The incumbent Primary User (PU) of the spectrum, with a weak transmission link, seeks cooperation from the cognitive Secondary User (SU) nodes in its vicinity, and in return rewards them with a fraction of time for their own communication, as an incentive time. The utility functions for both the entities of the CR network, i.e. the PU and SU, are formulated with two important considerations: the PU is the priority user and has a soft rate demand to be satisfied; and the SU's net utility involves a cost for relaying the PU's traffic. Maximizing the utilities of the PU and SU are conflicting objectives. After intensive analysis of the equilibrium point, we use a utility-based decision-making process to allocate that fraction of time to the PU and SU, which achieves optimum user satisfaction for both.