Power allocation for cognitive ad hoc network with relay assisted primary link

In this paper, power allocation for cognitive wireless network is investigated with the spectrum underlay strategy where primary users (PUs) and cognitive users (CUs) communicate via the same channel. We propose a scheme based on geometric programming to maximize the capacity of CUs keeping the interference to the PUs due to CUs below a threshold value maintaining the quality of service for the primary network. Then we extend the system to a relay assisted primary link scenario and simulation results show that simultaneous transmission in both primary links is possible when using the proposed power allocation method.