Dimitris E. Charilas

A survey on game theory applications in wireless networks

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.

Packet-switched network selection with the highest QoS in 4G networks

The evolution of telecommunications during the last decades has been enormous and as a result, nowadays, people find themselves before the challenge of 4G networks. Due to the fact that the latter constitute an environment of heterogeneous networks, their integration in terms of the Quality of Service (QoS) offered is of crucial importance. In general, the topic of this paper is to integrate the parameters that define QoS. Specifically, the main scope of this paper is the development of a process to evaluate three packet-switched networks (UMTS, WLAN and GPRS) in reference to the QoS offered and finally, the selection of the network that offers the highest standard for QoS. In order to achieve the above goal, there has been an attempt to distinguish the most important QoS indicators that characterize packet-switched networks and a few processes have been developed in order to either estimate the contribution of each parameter to the total QoS, or identify the weak points of a network. Apparently, each of these processes approaches the term of QoS in a different way and gives results of different usefulness.

Application of Fuzzy AHP and ELECTRE to Network Selection

In a heterogeneous wireless network environment services are ubiquitously delivered over multiple wireless access technologies. Ranking of the alternatives and selection of the most efficient and suitable access network to meet the QoS requirements of a specific service, as these are defined by the user, constitutes thus an important issue. Decisions on which network to connect to are however difficult to be reached, since multiple factors of different relative importance have to be taken into consideration. This paper addresses this difficulty by adopting Multi Attribute Decision Making (MADM) methods. Fuzzy AHP, a MADM method, is initially applied to determine the weights of certain Quality of Service indicators that act as the criteria impacting the decision process. The fuzzy extension of the method, and consequently the use of fuzzy numbers, is adopted in order to incorporate the existence of fuzziness as a result of subjective evaluations. Afterwards, ELECTRE, a ranking MADM method, is applied to rank the alternatives, in this case wireless networks, based on their overall performance.

Enhancing Quality of Experience in Next Generation Networks Through Network Selection Mechanisms

The evolution of telecommunications during the last decades has been enormous and as a result, nowadays, people find themselves before the challenge of 4G networks. Consequently, network selection techniques play a vital role in ensuring quality of experience (QoE) in heterogeneous networks. The main scope of this paper is the development of a process in order to compare packet-switched networks in terms of QoE offered and finally select the network that offers the highest standard of QoE. For this reason, main QoS parameters are identified and a scheme is proposed to identify each parameters importance based on network performance. The proposed methodology combines the analytical hierarchy process (AHP) to decide the relative weights of evaluative criteria set according to the networks performance, as well as the grey relational analysis (GRA) to rank the network alternatives. The proposed methodology is then applied for GPRS and WLAN.

A theoretical scheme for applying game theory and network selection mechanisms in access admission control

One of the main features of future networks will be heterogeneity in the wireless access environment in which a mobile terminal will be able to connect to multiple radio networks simultaneously. Network selection and efficient load balancing among different types of networks will be required to achieve high-speed connectivity with seamless mobility. Game theory is a mathematical tool developed to understand competitive situations in which rational decision makers interact to achieve their objectives. Game theory techniques can be easily adapted for use in radio resource management mechanisms in a heterogeneous environment. To this end, we propose here a theoretical scheme for fusing network selection mechanisms and game theory, so that access admission control can be modeled efficiently as a non-cooperative game. In this sense, networks play against each other so as to maximize their payoff and admission control policy ensures maximum QoS for all service requests.

ICARUS: hybrId inCentive mechAnism for coopeRation stimUlation in ad hoc networkS

Mobile ad hoc networks rely on the cooperation of nodes for routing and forwarding. However, individual nodes may not always be willing to cooperate. In order thus to stimulate cooperation in ad hoc networks, several incentive mechanisms have been developed. In this paper we propose a new hybrid incentive mechanism, called ICARUS, which is an extension of DARWIN, a well-known reputation-based mechanism, combining advantages of both reputation-based and credit-based mechanisms. The objective of ICARUS is to detect and punish selfish nodes efficiently and at the same time motivate nodes to cooperate by rewarding the packet forwarding. Furthermore, ICARUS ensures fairness for distant nodes and prevents selfish nodes from corrupting the system using false information. The proposed schemes performance is tested through extended series of simulations and is compared with DARWIN. We show that ICARUS detects and isolates selfish nodes much faster, while at the same time improves the Quality of Service (QoS) received by non-selfish nodes, including distant ones.

Congestion Avoidance Control through Non-cooperative Games between Customers and Service Providers

Congestion avoidance control refers to controlling the load of the network by restricting the admission of new user’s sessions and resolving the unwanted overload situations. Admission control and Load control constitute key mechanisms regarding Radio Resource Management. As the wireless world is moving towards heterogeneous wireless networks, these types of control are facing more challenges, since efficiency and fairness are required. Game theory provides an appropriate framework for formulating fair and efficient congestion avoidance control problems. In this paper we formulate a non-cooperative game between service providers and customers. On the one hand, the service providers wish to maximize their revenue, but on the other hand, the users wish to maximize the quality of service received, keeping at the same time the expenses as low as possible. Therefore a balance has to be established among these contradictory demands. Our effort also concentrates in the proper modeling of the user’s level of satisfaction, so as to provide a logical decision-taking framework. The proposed scheme is then tested using the ns2 simulator. Results show that both parties can benefit from this mechanism.

A Unified Network Selection Framework Using Principal Component Analysis and Multi Attribute Decision Making

Services are ubiquitously delivered over multiple wireless access technologies in a heterogeneous wireless network environment. A significant issue is the ranking of the alternative access networks and the selection of the most efficient and suitable one in order to meet the Quality of Service (QoS) requirements of a specific service, as these are defined by the user. With this way, the user receives enhanced Quality of Experience. However, decisions on which network to connect are usually difficult to be reached, since multiple factors of different importance have to be taken into consideration. The subject of the paper is the introduction of a novel unified network selection framework. A framework for defining decision criteria weights relying on the variance of network measurements is also provided. For this purpose, Principal Component Analysis and Analytic Hierarchy Process are deployed so as to unravel the patterns in data and retrieve parameter weights through pair wise comparisons respectively. The framework addresses the final network selection by the employment of Multi Attribute Decision Making methods and by using certain QoS indicators acting as figures of merit which influence the decision process. Finally, the proposed scheme is tested through extended simulations and a discussion over its performance is made. Some useful conclusions are drawn.

Adaptive neuro-fuzzy inference models for speech and video quality prediction in real-world mobile communication networks

This article presents a unified Quality of Service (QoS) prediction methodology based on neuro-fuzzy inference systems that can be used in contemporary rollout mobile communication networks. Our work is concentrated on radio key performance indicators of mobile radio access networks that affect speech and video quality of wireless multimedia communications, and on how we can estimate Quality of end-user Experience (QoE) using fuzzy-based techniques. We propose a methodology that is based on modern experimental drive-test equipment with which a measurement campaign is configured and conducted in various environments. Afterwards, ANFIS models are developed based on real network measurements and numerical results are presented.

Fuzzy-based handover decision with multi-attribute auctions in heterogeneous network environments

In next generation wireless networks mobile users will be able to roam between heterogeneous networks, using terminals with multiple access interfaces. An important issue in such a heterogeneous environment is the provisioning of seamless mobility to users across heterogeneous access networks, according to the Always Best Connected and Served (ABCS we also explain how the mobile terminals rank the available offers by the networks. A handover is performed only if a networks offer is considered more satisfactory than current status. Finally, a discussion is made through numerical paradigm and simulations, highlighting the proposed schemes effectiveness.