Resource Optimization Using Bandwidth-Power Product in Relay Aided Cognitive Radio Networks

This paper aims to investigate the resource allocation problem in a relay-assisted OFDMA cognitive radio (CR) system. Different from conventional CR resource allocation problems, a joint bandwidth and power optimization framework using the bandwidth-power product metric is proposed. Besides, rate requirement of the secondary system is satisfied and interference power at the primary receiver is limited. Meanwhile channel pairing at the relay terminal is operated so that signal received over a particular channel at the first hop can be forwarded over a different channel at the second hop. The problem is found to be nonconvex and intractable to seek for an optimal solution. Hence, using the Lagrangian-Dual and Gauss-Newton methods, a sub-optimal algorithm with low complexity is proposed. Numerical results are provided to validate the superiority of the proposed method compared to conventional power optimization methods using the waterfilling scheme.