Energy-efficient nonstationary power control in cognitive radio networks

Spectrum sharing policies are essential for cognitive radio networks, where primary and secondary users aim to minimize their average energy consumptions subject to minimum throughput requirements. Most existing works proposed stationary spectrum sharing policies, in which users transmit simultaneously at fixed power levels, and need to transmit at high power levels due to multi-user interference. In this paper, we propose nonstationary spectrum sharing policies in which users transmit in a TDMA fashion (but not necessarily in a round-robin manner). Due to the absence of multi-user interference and the ability to let users adaptively switch between transmission and dormancy, our proposed policy greatly improves the spectrum and energy efficiency, and ensures no interference to primary users. Moreover, the proposed policy achieves high energy efficiency even when users have erroneous and binary feedback about their received interference and noise power levels. The proposed policy is also deviation-proof, namely the autonomous users find it in their self-interests to comply with the policy. The proposed policy can be implemented by each user running a low-complexity algorithm in a distributed fashion. Compared to existing policies, the proposed policies can achieve an energy saving of up to 80%.