To Cooperate or Not to Cooperate: System Throughput and Fairness Perspective

The cooperative transmission, in which some nodes help the transmission of other nodes, has been actively studied to overcome the channel fading effects that deteriorate the communication quality. Thus far, most researches on the cooperative transmission have been studied from the reliability point of view focusing on a single transmission and showing that the cooperative transmission can increase transmission reliability. In this paper, we study the effects of the cooperative transmission from the system throughput and fairness point of view, considering the following fundamental questions: Is the cooperative transmission always helpful to increase the system throughput and improve the degree of fairness among nodes? If not, when is it helpful to increase the system throughput and improve the degree of fairness among nodes? We provide the answers to the above questions with a simple system in which two source nodes are capable of being cooperative with each other by using the decode-and-forward cooperative scheme to transmit their data to a single destination node.