Resource allocation schemes for cooperative relay-based cognitive radio with imperfect channel state information

Relay-based cooperative communication can be applied to cognitive radio (CR) networks to improve their spectral efficiency in the absence of strong direct path between secondary user (SU) source and destination. Availability of channel state information (CSI) of the channels between various nodes is critical for optimal resource allocation in order to realize the potential advantages of such systems. However, in a practical system, CSI is often imperfect. We discuss various methods of opportunistic allocation of available transmit power and systematic selection of relays for a CR system in presence of imperfect CSI. The imperfectness in the CSI occurs due to channel estimation error which is modeled as additive white Gaussian noise (AWGN). The benefits of proposed methods are presented based on computer-based simulation results.