Using game theory to analyze wireless ad hoc networks

Lecture Notes in Computer Science, 2005

Wireless Ad-hoc networks are expected to be made up of energy aware entities (nodes) interested in their own perceived performance. We consider a simple random access model for a wireless ad hoc network to address problems of finding an optimal channel access rate and providing incentive for cooperation to forward other nodes' traffic. By casting these problems as noncooperative games, we derive conditions for the Nash equilibrium and provide distributed algorithms to learn the Nash equilibrium.

Game theory is a set of tools developed to model interactions between agents with conflicting interests . It is a field of applied mathematics that defines and evaluates interactive decision situations. It provides analytical tools to predict the outcome of complicated interactions between rational entities, where rationality demands strict adherence to a strategy based on observed or measured results . Originally developed to model problems in the field of economics, game theory has recently been applied to network problems, in most cases to solve the resource allocation problems in a competitive environment. The reason that game theory is an adapted choice for studying cooperative communications is various. Nodes in the network are independent agents, making decisions only for their own interests. Game theory provides us sufficient theoretical tools to analyze the network users' behaviors and actions. Game theory, also primarily deals with distributed optimization, which often requires local information only. Thus it enables us to design distributed algorithms. . This article surveys the literature on game theory as they apply to wireless networks. First, a brief overview of classifications of games, important definitions used in games (Nash Equilibrium, Pareto efficiency, Pure, Mixed and Fully mixed strategies) and game models are presented. Then, we identified five areas of application of game theory in wireless networks; therefore, we discuss related work to game theory in communication networks, cognitive radio networks, wireless sensor networks, resource allocation and power control. Finally, we discuss the limitations of the application of game theory in wireless networks.

2013

In wireless communication networks, many protocols (e.g., IEEE 802.11 a/b/g Medium Access Control (MAC) protocols) have been designed assuming that users are compliant with the protocol rules. Unfortunately, a self-interested and strategic user might manipulate the protocol to obtain a personal advantage at the expense of the other users. This would lead to socially inefficient outcomes. In this thesis we address the problem of designing protocols that are able to avoid or limit the inefficiencies occurring when the users act selfishly and strategically. To do so, we exploit the tools offered by Game Theory (GT), the branch of mathematics that models and analyzes the interaction between strategic decision makers. The dissertation covers aspects related to wireless communications at different levels. We start analyzing the downlink radio resource allocation issue of a cellular network based on Orthogonal Frequency Division Multiple Access (OFDMA). We propose a suboptimal game theoretic algorithm able to preserve the modularity of the system and to trade-off between sum-rate throughput and fairness among the users of the network. Successively, we address the problem of promoting cooperation in wireless relay networks. To give the incentive for the users of a network to relay the packets sent by other users, we consider a dynamic scheduling in which cooperative users are rewarded with more channel access opportunities. Infrastructure sharing is another form of cooperation that might be exploit to meet the increasing rate demands and quality of service requirements in wireless networks. We analyze a scenario where two wireless multi-hop networks are willing to share some of their nodes-acting as relays-in order to gain benefits in terms of lower packet delivery delay and reduced loss probability. Bayesian Network analysis is exploited to compute the correlation between local parameters and overall performance, whereas the selection of the nodes to share is made by means of a game theoretic approach. Afterwards, our analysis focuses on channel access policies in wireless ad-hoc networks. We design schemes based on pricing and intervention to give incentives for the users to access the channel efficiently.

Computer Networks, 2010

While the Quality of Service (QoS) offered to users may be enhanced through innovative protocols and new technologies, future trends should take into account the efficiency of resource allocation and network/terminal cooperation as well. Game theory techniques have widely been applied to various engineering design problems in which the action of one component has impact on (and perhaps conflicts with) that of any other component. Therefore, game formulations are used, and a stable solution for the players is obtained through the concept of equilibrium. This survey collects applications of game theory in wireless networking and presents them in a layered perspective, emphasizing on which fields game theory could be effectively applied. To this end, several games are modeled and their key features are exposed.

2008

This paper presents a game theoretic model aimed at optimizing the performance of medium access control in ad-hoc wireless networks. IEEE 802.11 is the commonly used protocol in such networks, so our model is specifically tailored for it. The network of wireless nodes is abstracted into a community of selfish users playing a non-cooperative game. The resource they vie for is the common random-access wireless channel. We define new utility functions for the nodes and show that these utility functions have insightful and elegant mathematical properties to steer the game to a unique non-trivial Nash equilibrium. This defines a stable operating point from which no player has an incentive to deviate unilaterally. At this stable point each node has an equal non-trivial share of the common wireless transmission channel. Thus selfish behavior of the nodes is used as a mechanism to enforce desirable properties of the network as a whole. Simulations show that this design scores over the traditional Distributed Coordination Function (DCF) in IEEE 802.11 MAC in terms of throughput and collision overhead, thus greatly improving the system-wide MAC layer performance of the network. Since the utility functions produce high performance objectives over a wide range of network sizes in a completely distributed fashion with the nodes behaving selfishly, a self-enforcing mechanism for efficient working of ad-hoc and large unattended networks of constrained wireless devices is achieved.

IEEE Transactions on Systems, Man, and Cybernetics, Part B (Cybernetics), 2010

Traditional networks are built on the assumption that network entities cooperate based on a mandatory network communication semantic to achieve desirable qualities such as efficiency and scalability. Over the years, this assumption has been eroded by the emergence of users that alter network behavior in a way to benefit themselves at the expense of others. At one extreme, a malicious user/node may eavesdrop on sensitive data or deliberately inject packets into the network to disrupt network operations. The solution to this generally lies in encryption and authentication. In contrast, a rational node acts only to achieve an outcome that he desires most. In such a case, cooperation is still achievable if the outcome is to the best interest of the node. The node misbehavior problem would be more pronounced in multihop wireless networks like mobile ad hoc and sensor networks, which are typically made up of wireless battery-powered devices that must cooperate to forward packets for one another. However, cooperation may be hard to maintain as it consumes scarce resources such as bandwidth, computational power, and battery power. This paper applies game theory to achieve collusive networking behavior in such network environments. In this paper, pricing, promiscuous listening, and mass punishments are avoided altogether. Our model builds on recent work in the field of Economics on the theory of imperfect private monitoring for the dynamic Bertrand oligopoly, and adapts it to the wireless multihop network. The model derives conditions for collusive packet forwarding, truthful routing broadcasts, and packet acknowledgments under a lossy wireless multihop environment, thus capturing many important characteristics of the network layer and link layer in one integrated analysis that has not been achieved previously. We also provide a proof of the viability of the model under a theoretical wireless environment. Finally, we show how the model can be applied to design a generic protocol which we call the Selfishness Resilient Resource Reservation protocol, and validate the effectiveness of this protocol in ensuring cooperation using simulations.

Game theory has been recently introduced in wireless network design as a powerful modeling and analysing tool for competitive and completely distributed environments. It is a well-suited to describe mutual conflicting situations between multiple devices which attempt to communicate through a shared medium. In order to demonstrate suitability of a game-theoretic approach for optimisation of wireless networks, we first present the main idea, concepts and components of game theory. We then provide mapping of principles between the areas of game theory and wireless networks, and present some applications of game theory in wireless networks. We develop and implement a model for transmit power control optimisation in a wireless relay network consisting of wireless sensor network coordinator nodes using the category of potential games. In the game, we determine the Pareto efficient Nash equilibrium, which represents the optimal stable operating point of the network.

2009

The ability to model individual, independent decision makers whose actions potentially affect all other decision makers renders game theory particularly attractive to apply to various fields of Information technology, especially, to analyze the performance of wireless networks. In this paper, we discuss how various interactions in cognitive radio based wireless networks can be modeled as a game at different levels of protocol stack. This allows the analysis of existing protocols and resource management schemes, as well as the design of equilibrium-inducing mechanisms that provide incentives for individual users to behave in socially-constructive ways. In nutshell, this paper serves two main objectives; first, to model some of the fundamental questions on cognitive radio based wireless networks as interactive games between the nodes and second, to gain our understanding on inter-discipline research issues.

Ad Hoc Networks, 2011

We consider a distributed joint random access and power control scheme for interference management in wireless ad hoc networks. To derive decentralized solutions that do not require any cooperation among the users, we formulate this problem as noncooperative joint random access and power control game, in which each user minimizes its average transmission cost with a given rate constraint. Using

2009

Résumé: To cope with the fast development of decentralized wire-less communications, game theory has been considered as a necessary and powerful mathematical tool to study the com-petition and cooperation between future intelligent wireless devices. This paper surveys the state-of-the-art of game-theoretical tools applied to wireless communications, focus-ing mainly on the analysis of wireless resource allocation problems.