基于博弈论的机会网络激励机制的研究

Novel game-based incentive strategy for opportunistic networks

机会网络是一种新型的网络,具有频繁的网络断开、高误码率、随机的拓扑变化等特点,该网络中的消息传播是依靠节点间的合作来完成存储—携带—转发的模式。由于能量、缓存以及处理能力的限制,一些节点表现出自私(拒绝帮助其他节点转发消息),甚至恶意(高报价)的特性,所以会给网络性能带来巨大的损失(低交付率、长延迟等)。为了解决上面的问题,现存的基于虚拟货币的激励机制,如Credit,它依靠一个固定的中心来管理源节点向为它转发消息的中继节点支付虚拟货币的交易。但这个固定的管理中心在缺乏基础设施的机会网络中是很难实现的,所以提出一种新的基于博弈论的激励机制——GIS(game-based incentive strategy)。该机制主要利用三次讨价还价博弈让交易双方在缺乏第三方管理的情况下仍然以合理的价格进行交易,它除了能够刺激自私节点的合作之外,最大的优势就是抑制恶意中继的虚假报价。大量实验表明,GIS能够很好地优化网络交付率和平均延迟,使得网络的有效性和公平性得到保证。

Opportunistic networks are the emerging networks characterized by frequent network partitions, high bit error ratio and random topology instability, where the message propagation depends on the cooperation of nodes to fulfill a ＂store-carry-forward＂ fashion. Due to the confine of energy, memory and processing capacity, some individual nodes may behave selfishly, or even maliciously, which will introduce damage into the existing routing schemes based on cooperation and degrade the performance （ lower delivery ratio, longer latency etc. , ） of opportunistic networks greatly. In order to address the above issues, the current price-based incentive strategy, Credit relies on a fixed management-center which is rare in the realistic opportunistic networks with little infrastructure to manage the transaction that the source of messages pays virtual credits to nodes that relay messages for it. So this paper proposed a novel game-based incentive strategy （GIS） which utilized three-time bargaining model based on two-person transaction and allowed the sending nodes to pay the relay nodes directly according to the optimal price drawn by game without any third party. GIS stimulated the cooperation of selfish nodes to forward messages effectively, while held back the deceptive price stemmed from the malicious intermediary nodes to facilitate deals. From the extensive simulations results, GIS can optimize the average latency and the delivery ratio to the greatest extent. Additionally, it can guarantedd effectiveness and fairness.