  We propose a distributed spectrum access algorithm for cognitive radio relay
networks with multiple primary users (PU) and multiple secondary users (SU).
The key idea behind the proposed algorithm is that the PUs negotiate with the
SUs on both the amount of monetary compensation, and the amount of time the SUs
are either (i) allowed spectrum access, or (ii) cooperatively relaying the PU's
data, such that both the PUs' and the SUs' minimum rate requirement are
satisfied. The proposed algorithm is shown to be flexible in prioritizing
either the primary or the secondary users. We prove that the proposed algorithm
will result in the best possible stable matching and is weak Pareto optimal.
Numerical analysis also reveal that the distributed algorithm can achieve a
performance comparable to an optimal centralized solution, but with
significantly less overhead and complexity.
