Primary and secondary QoS guranteed spectrum sharing protocol with optimal time allocation

In this paper, we propose a collaborative spectrum sharing protocol which aims to maximize the sum transmission rate while the quality-of-service (QoS) of both primary and secondary systems´ can be supported. Specifically, the primary system authorizes the secondary system to access its spectrum band with a fraction of transmission time only when it can help the primary system achieve the target rate. During the accessing time, the secondary system assigns half power to help primary system reach the target rate and utilizes the remaining half power to transmit its own signal. We determine an optimal time allocation by analyzing the sum transmission rate of primary and secondary systems with both of their QoS can be ensured. Simulation results show that the efficiency of the proposed spectrum sharing protocol and both primary and secondary systems can benefit from it.