A Low-Interference Relay Selection for Decode-and-Forward Cooperative Network in Underlay Cognitive Radio
In the underlay Decode-and-Forward (DaF) cooperative Cognitive Radio (CR) network, an optimal relay can be selected by the conventional max-min selection on the condition of not violating the Interference Temperature (IT) limit. However, the max-min selection may cause some extra amount of interference to the Primary System (PS) such that the so-called Transfer Ratio (TR) can be lower. Note that TR is newly defined as the ratio of the Secondary System's (SS's) capacity gain to the PS's capacity loss due to the activities of SS. In order to improve the TR value, the authors are motivated by the pricing function in Game theory to propose a novel low-interference relay selection by taking the impacts of the interference from SS to PS into consideration.