采用博弈论的认知无线网络主用户和不可信任次用户的协作策略
Cooperation Schemes Between the Primary Transmitter and Untrusted Secondary Transmitters in Cognitive Radio Networks Using Game Theory

针对认知无线网络中不可信任的次用户发送者(ST)会对主链路进行窃听的问题,以将主用户发送者(PT)和ST之间的敌对关系转化为协作关系为目的,提出2种采用博弈论的协作策略:斯塔伯格策略及其改进策略――双层博弈策略。在斯塔伯格策略中,ST工作于半双工模式,和窃听相比,它更希望传送数据,因此PT轮流和每个ST进行斯塔伯格博弈,选择对未被选中的ST(即潜在的窃听者)产生更多干扰的ST一起使用授权频段发送数据。为促进ST之间的竞争,将斯塔伯格策略扩展为双层博弈策略,外层仍是斯塔伯格策略,PT将所有的ST看作一个整体进行博弈;内层拍卖博弈中,每个ST尽可能提高安全速率来赢得接入授权频段的机会,PT则选择能提供最高安全速率的ST进行合作,因此它能够获得更高的收益。仿真结果表明,在这2种策略作用下,主链路的安全速率分别提高了63％和68％,ST接入授权频段的概率分别为56％和71％。
Two cooperation schemes using game theory are proposed to solve the problem that the untrusted secondary transmitters(STs) will eavesdrop on the primary link in cognitive radio networks and to covert the hostile relation between the primary transmitter(PT) and STs into a cooperative one, and they are a Stackelberg scheme and an improved two？？layer game.The STs work in half？？duplex and prefer to transmit than to eavesdrop in the Stackelberg scheme. Hence, the PT plays the Stackelberg game with each ST, and then selects the ST who creates more interference to the unselected STs(i？？e. the potential eavesdroppers) to transmit simultaneously. The Stackelberg scheme is then extended into a two？？layer game to facilitate the competition among the STs. The outer framework is still a Stackelberg model and the PT plays game with all the STs as an entity, while the inner has an auction framework in which each ST improves its security rate as much as possible for the access opportunity. The PT will conduct cooperation with the ST having the highest security rate, so that more profit can be obtained. Numerical results show that application of these two proposed schemes results in a significant improvement: the security rate of the two schemes increases by 63% and 68% respectively, and the access opportunity of STs is 56% and 71% respectively