Achieving cooperation in multihop wireless networks of selfish nodes
Achieving cooperation in multihop wireless networks of selfish nodes
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DOI：
10.1145/1190195.1190197
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发表时间：
2006-10
期刊：
影响因子：
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通讯作者：
F. Milan;J. J. Jaramillo-J.;R. Srikant
中科院分区：
文献类型：
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作者：
F. Milan;J. J. Jaramillo-J.;R. Srikant
在多跳无线网络中，将数据包从源路由到目的地需要节点之间的协作。如果节点是自私的，则可以使用基于声誉的机制来维持合作，而无需求助于中央权威。在逐跳的基于信誉的机制中，每个节点都监听其中继邻居，并且根据一报还一达特的策略，行为不端的节点会被丢弃一小部分数据包。分组冲突可能会阻止节点识别正确的传输，从而扭曲所评估的信誉。因此，即使所有的节点都愿意合作，由感知到的背叛触发的报复可能最终导致零吞吐量。这个问题的经典解决方案是在纯粹的达特策略中增加一个容忍阈值，这样有限数量的背叛将不会受到惩罚。在本文中，我们提出了一个博弈论模型，研究冲突的影响，一个逐跳的信誉为基础的机制，定期网络均匀的随机流量。我们的研究结果表明，一个慷慨的达特的策略的纳什均衡是合作的任何允许的负载，如果节点是足够有远见的，或者等价地，如果一个数据包的节点的值是足够高的传输成本。我们还研究了两种更严厉的惩罚机制，即一步触发和严峻的触发，可以实现在温和的条件下的合作。
In a multihop wireless network, routing a packet from source to destination requires cooperation among nodes. If nodes are selfish, reputation-based mechanisms can be used to sustain cooperation without resorting to a central authority. Within a hop-by-hop reputation-based mechanism, every node listens to its relaying neighbors, and the misbehaving ones are punished by dropping a fraction of their packets, according to a Tit-for-tat strategy. Packet collisions may prevent a node from recognizing a correct transmission, distorting the evaluated reputation. Therefore, even if all the nodes are willing to cooperate, the retaliation triggered by a perceived defection may eventually lead to zero throughput. A classical solution to this problem is to add a tolerance threshold to the pure Tit-for-tat strategy, so that a limited number of defections will not be punished. In this paper, we propose a game-theoretic model to study the impact of collisions on a hop-by-hop reputation-based mechanism for regular networks with uniform random traffic. Our results show that the Nash Equilibrium of a Generous Tit-for-tat strategy is cooperative for any admissible load, if the nodes are sufficiently far-sighted, or equivalently if the value for a packet to the nodes is sufficiently high with respect to the transmission cost. We also study two more severe punishment schemes, namely One-step Trigger and Grim Trigger, that can achieve cooperation under milder conditions.