Power Allocation in Cooperative Communication System Based on Coalitional Game

Sometimes, the source node can't satisfy the QoS requirement with the only relay node. It is the better choice to need multiple relay nodes. In other case, the number of hops between the source node and the far off destination node may be reduced, with the help of several relay nodes. But the power allocation in multi-relay cooperative communication is complex. We adopt coalitional game theory to deal with the issue. The selected relay nodes are glad to form a group to work together, because their transmit power can be reduced. Specially, the nodes in ad hoc networks are more interested in it. Since wireless nodes are power constrained, the dedicative relay nodes don't always care nothing about their own power consumed. Concretely, we design the characteristic function based on the target SNR of the destination node to guarantee these relay nodes can form the grand coalition and the coalition is stable. The solution under the Shapley value is averagely fair. Then we can decide the power of the relay node according to the solution. Moreover, we exploit consider coalition formation theory to consider multi-relay selection and power allocation jointly. The coalition formation process corresponds to multi-relay selection process, and power allocation of relay node is confirmed via a coalition formation strategy based on benefit equilibrium. The strategies are beneficial to the formation of global coalition which is stable.