Optimal throughput curve for primary and secondary users with node-level cooperation

A new trend in cooperation is to allow the primary and secondary networks to cooperate on the node level for data forwarding, which we call the UPS paradigm. This paper offers an in-depth study of the UPS paradigm in terms of its optimal throughput curve - the maximum achievable throughput for both primary and secondary users. We formulate the problem into a multicriteria optimization problem with the goal of maximizing the throughput of both primary and secondary users. Through a novel approach based on weighted Chebyshev norm, we transform the multicriteria optimization problem into a single criteria optimization problem and find a sequence of Pareto-optimal points iteratively. Based on the Pareto-optimal points, we find the throughput curve and show that it is ε-approximation to the optimal. Through a case study, we show that the throughput region (the area under the throughput curve) under a UPS paradigm is substantially larger than that under the interweave paradigm.