Study on cooperative communication in energy constrained networks

Diversity gain can be achieved when cooperative transmission adopted in the wireless networks, which can provide much help to weak channel communication. Much has been done on the cooperative protocol and the performance analysis. In this paper, a new cooperative schedule is proposed. In which we have discussed three issues: when cooperative transmission should be adopted, how to choose the relay node and how to forward the data packet. The major difference with other protocols is that the relay node forwards data with power as smaller as possible during cooperative transmission. For this reason, the destination node can receive the data successfully without consuming too much energy of the relay node with less interference. Further more, it can avoid the consequence such as that some of the nodes involved in cooperation frequently and run out of energy too fast. Analysis results prove that cooperative schedule can improve SNR at the receiver and reduce packet loss rate. With smaller forward power, this protocol can increase spatial reuse and overall network performance compared to the protocol of relay node with fixed transmitting power.