Energy-efficient and low-complexity schemes for uplink cognitive cellular networks

This Letter proposes two types of energy-efficient and low-complexity schemes for uplink cognitive cellular networks. In the considered system, both cognitive users (CUs) and primary user (PU) share the same base station (BS). Under an outage probability protection criterion for the PU, we firstly propose a round-robin CU scheduling scheme and analytically show its achieved signal-to-interference ratio statistics at the BS, from which it is observed that the round-robin scheduling is much more energy-efficient than opportunistic scheduling to achieve the same mean capacity and bit error rate. Inspired by this interesting observation, a statistics-based CU scheduling scheme is also presented, whose energy-efficiency is further improved.