Study On The Game Strategies For Cooperative Relay Of Selfish Wireless Nodes

In a wireless communication system, nodes can forwards information for eachother through cooperative relay. Studies have shown cooperative relay can bothimprove the quality of wireless communication and expand the coverage area of it. Soas a promising wireless transmission technology, cooperative relay has become aresearch focus in recent years.Nowadays in the academic area, about cooperative relay, the research time isrelatively short, the research fields are fairly narrow, and the research depth is notenough too. A typical proof is most of the studies are based on the selflessness ofwireless nodes. But for the vast majority of real wireless networks, the componentnodes are selfish. Thereby studies of cooperative relay on selfless nodes are obviouslynot suitable for selfish ones. According to selfish wireless cooperative relay systems,we must design appropriate incentive mechanism to make selfish nodes initiativelyparticipate in cooperative relay.The game theory has been proved an effective way to address resource allocationissue in selfish wireless cooperative relay networks. Also, it is the core research stuffof my paper. The main contributions of the paper are summarized as follows.1. Studies on three fundamental network models of cooperative relay.●Game strategies for selfish two-node resource allocation based on symmetriccooperative relay. Aiming at amplify-and-forward and decode-and-forward protocol inselfish two-node cooperative networks, we propose a fair and efficient powerallocation scheme respectively. First, we formulate this cooperative power allocationproblem as a two-node cooperative game. Then we solve the Nash bargaining solutionto achieve a win-win strategy for both partner nodes. Finally, the computer simulationis presented to verify the solution meets both the efficiency and the fairness.●Game strategies for selfish single-source-multi-relay resource allocation basedon symmetric cooperative relay. A source node would like to achieve the optimalbenefit, while the relaying nodes are willing to get rewards from the source for thecooperative relaying. First, we define the cooperative strategy of a node as the fractionof a data-frame that it is willing to contribute to its partners. Then, we formulate thisresource sharing problem as a Nash bargaining problem. After, we propose a fastparticle swarm optimizer algorithm to search for the Nash bargaining solution.Simulation results show that the two specified objectives of the source and the relays can both be implemented by the proposed game.●Game strategies for selfish multi-source and multi-relay resource allocationbased on asymmetric cooperative relay. First, regarding the spectrum resource that arelay is willing to contribute for a source as the cooperative strategy, the joint relayselection and spectrum allocation problem is formulated as a cooperative bargaininggame. Then, the existence of a unique Nash bargaining solution to the game is proved.And then a Langrangian relaxation with iterative search approach is proposed toquickly find the solution. By comparing with the maximal-rate and the max-min basedschemes, simulation results show that the proposed bargaining game approachachieves a fair and efficient rates distribution among the sources.2. Studies on two application scenarios of cooperative relay.●Bargaining game of joint resource allocation for selfish relay-aided OFDMAnetworks. First, we define a user’s game utility as a function of its transmission rateand formulate the joint resource allocation problem as a cooperative game. Then, toobtain the Nash bargaining solution, we divide the joint resource allocation game intotwo subgames, the subcarrier allocation game and the power allocation game. After,using this scheme, the jointly optimal subcarrier and power allocation are achieved inan iterative manner. Finally, simulations prove the proposed game could achieve agood tradeoff between the per-node fairness and the overall system efficiency.●Nash equilibrium based cooperative relay for selfish cognitive radio networks.In a cognitive radio system, considering a unlicensed secondary user (USU) needsdynamically upgrade its QoS demand, we proposes a Nash equilibrium basedspectrum allocation scheme to assist the USU to achieve the QoS demand in afull-loaded network on the condition that the performance of the related licensedprimary user (LPU) is not degraded. Our concern is how to make the LPU be willingto split extra amount of spectrum to the USU. We design the newly-obtained extraspectrum by the USU for two purposes, compensating the LPU by providingperformance improvement through cooperative relay and transmitting the USU’s ownmessages to achieve the new QoS demand. Simulation results show that the increasedQoS demand of the USU can be fulfilled while the minimum rate requirements of theLPU can be well ensured through the proposed game approach.