Olga Ormond

Game Theory-Based Network Selection: Solutions and Challenges

In order to cater for the overwhelming growth in bandwidth demand from mobile Internet users operators have started to deploy different, overlapping radio access network technologies. One important challenge in such a heterogeneous wireless environment is to enable network selection mechanisms in order to keep the mobile users Always Best Connected (ABC) anywhere and anytime. Game theory techniques have been receiving growing attention in recent years as they can be adopted in order to model and understand competitive and cooperative scenarios between rational decision makers. This paper presents an overview of the network selection decision problem and challenges, a comprehensive classification of related game theoretic approaches and a discussion on the application of game theory to the network selection problem faced by the next generation of 4G wireless networks.

Energy consumption analysis of video streaming to Android mobile devices

Energy conservation has become a critical issue around the world. In smart phones, battery power capabilities are not keeping up with the advances in other technologies (e.g., processing and memory) and are rapidly becoming a concern, especially in view of the growth in usage of energy-hungry mobile multimedia streaming. The deficiency in battery power and the need for reduced energy consumption provides motivation for researchers to develop energy efficient techniques in order to manage the power consumption in next-generation wireless networks. As there is little analysis in the literature on the relationship between the wireless environment and the mobile device energy consumption, this paper investigates the impact of network-related factors (e.g., network load and signal quality level) on the power consumption of the mobile device in the context of video delivery. This paper analyzes the energy consumption of an Android device and the efficiency of the system in several scenarios while performing video delivery (over UDP or TCP) on an IEEE 802.11g network. The results show that the network load and the signal quality level have a combined significant impact on the energy consumption. This analysis can be further used when proposing energy efficient adaptive multimedia and handover mechanisms.

Reputation-based network selection mechanism using game theory

Current and future wireless environments are based on the coexistence of multiple networks supported by various access technologies deployed by different operators. As wireless network deployments increase, their usage is also experiencing a significant growth. In this heterogeneous multi-technology multi-application multi-terminal multi-user environment users will be able to freely connect to any of the available access technologies. Network selection mechanisms will be required in order to keep mobile users “always best connected” anywhere and anytime. In such a heterogeneous environment, game theory techniques can be adopted in order to understand and model competitive or cooperative scenarios between rational decision makers. In this work we propose a theoretical framework for combining reputation-based systems, game theory and network selection mechanism. We define a network reputation factor which reflects the network’s previous behaviour in assuring service guarantees to the user. Using the repeated Prisoner’s Dilemma game, we model the user–network interaction as a cooperative game and we show that by defining incentives for cooperation and disincentives against defecting on service guarantees, repeated interaction sustains cooperation.

Enhanced Power-Friendly Access Network Selection Strategy for Multimedia Delivery Over Heterogeneous Wireless Networks

The continuing growth in video content exchanged by mobile users creates challenges for the network service providers in terms of supporting seamless multimedia delivery at high quality levels, especially given the existing wireless network resources. A solution that deals with this mobile broadband data growth is to make use of multiple networks supported by diverse radio access technologies. This multiaccess solution requires innovative network selection mechanisms to keep the mobile users always best connected anywhere and anytime. Additionally, there is a need to develop energy efficient techniques in order to reduce power consumption in next-generation wireless networks, while meeting user quality expectations. In this context, this paper proposes an enhanced power-friendly access network selection solution (E-PoFANS) for multimedia delivery over heterogeneous wireless networks. E-PoFANS enables the battery of the mobile device to last longer, while performing multimedia content delivery, and maintains an acceptable user perceived quality by selecting the network that offers the best energy-quality tradeoff. Based on real test-bed measurements, the proposed solution is modeled and validated through simulations. The results show how by using E-PoFANS, the users achieve up to 30% more energy savings with insignificant degradation in quality, in comparison with another state-of-the-art energy efficient network selection solution.

Energy–Quality–Cost Tradeoff in a Multimedia-Based Heterogeneous Wireless Network Environment

User mobility, heterogeneity of networks and network technologies, variety of mobile devices (e.g., different operating systems, display size, CPU capabilities, battery limitations), and wide range of video-centric applications (e.g., video on demand, video games, live video streaming, video conferences, surveillance) open up the demand for user-centric solutions that adapt the video application to the underlying network conditions and device characteristics. In addition, the absence of battery improvements suitable to meet the growing power requirements and the need for green Information and Communications Technologies ICT provides strong motivation for researchers to develop energy efficient techniques to manage and reduce power consumption in next-generation wireless networks, while still meeting high user quality expectations. In this context, we propose adapt-or-handover, a hybrid multimedia delivery solution, which balances the benefits of multimedia content adaptation and of network selection to decrease power consumption in a heterogeneous wireless network environment. The proposed solution is analyzed and comparatively tested through simulations. The results show how, by using adapt-or-handover, the users benefit from up to 31% energy savings with insignificant degradation in quality, in comparison with other energy efficient solutions.

Power-friendly access network selection strategy for heterogeneous wireless multimedia networks

Apart from the number and types of applications available to users of diverse devices with various characteristics, a highly relevant issue in current and future wireless environment is the coexistence of multiple networks supported by various access technologies deployed by different operators. In this context, the aim is to keep the mobile users “always best connected” anywhere and anytime in such a multi-technology multi-application multi-terminal multi-user environment. Multimedia streaming to battery powered mobile devices has become widespread. However, the battery power capability has not kept up with the advances in other technologies and it is rapidly becoming a concern. Since multimedia applications are known to be high energy consumers and since the battery life-time is an important factor for mobile users, this paper proposes a network selection algorithm which bases its decision on the estimated energy consumption. The proposed solution enables the multimedia stream to last longer while maintaining an acceptable user perceived quality by selecting the least power consuming network.

Quality Utility modelling for multimedia applications for Android Mobile devices

With the advances in mobile technologies, smart mobile computing devices have become increasingly affordable and powerful, leading to a significant growth in both the number of advanced mobile users and their bandwidth demands. Moreover multimedia streaming to these high-end mobile devices has become widespread. However, multimedia applications are known to be resource-hungry and in order to cope with this explosion of data traffic, operators have started deploying different, overlapping radio access network technologies. One important challenge in such a heterogeneous wireless environment is to ensure an Always Best Experience to the mobile user, anywhere and anytime. This paper proposes the Quality Utility, a realistic mapping function of the received bandwidth to user satisfaction for multimedia streaming applications. The Quality Utility is mapped to a Google Nexus One Android Mobile device and validated through objective and subjective tests.

Performance evaluation of MADM-based methods for network selection in a multimedia wireless environment

As mobile devices have become more affordable, easy to use and powerful, the number of mobile users and their bandwidth demands have experienced a significant growth. Considering the rising popularity of power hungry applications (e.g., multimedia), battery power capacity is an important concern—as upgrades are not keeping up with the advances in other technologies (e.g., central processing unit and memory). Mobile users now demand better power and battery management techniques to prolong their mobile battery performance. This, together with the need for green information communications technology, provides motivation for researchers to develop energy efficient techniques to reduce the power consumption in next-generation wireless networks while meeting user’s quality expectations. This paper conducts a realistic performance evaluation of a number of widely used multi attribute decision making (MADM)-based methods for network selection that aim at keeping the mobile users Always Best Connected anywhere and anytime. The main trade-off parameters considered include energy efficiency and user perceived quality levels for multimedia streaming. The energy consumption is modeled using real experimental results for an android mobile device. Similarly, the multimedia quality function was modeled using real user data, combined with a qualitative study to determine the resulting mean opinion scores. The performance analysis shows that the weighted multiplicative method (MEW) finds a better energy-quality trade-off for users in a heterogeneous wireless environment in comparison with three other MADM solutions.

StriFA: Stride Finite Automata for High-Speed Regular Expression Matching in Network Intrusion Detection Systems

Deep packet inspection has become a key component in network intrusion detection systems (NIDSes), where every packet in the incoming data stream needs to be compared with patterns in an attack database, byte-by-byte, using either string matching or regular expression matching. Regular expression matching, despite its flexibility and efficiency in attack identification, brings significantly high computation and storage complexities to NIDSes, making line-rate packet processing a challenging task. In this paper, we present stride finite automata (StriFA), a novel finite automata family, to accelerate both string matching and regular expression matching. Different from conventional finite automata, which scan the entire traffic stream to locate malicious information, a StriFA only needs to scan a partial traffic stream to find suspicious information. The presented StriFA technique has been implemented in software and evaluated based on different traces. The simulation results show that the StriFA acceleration scheme offers an increased speed over traditional nondeterministic finite automaton/deterministic finite automaton, while at the same time reducing the memory requirement.

On the impact of wireless network traffic location and access technology on mobile device energy consumption

In the context of wireless users increasing demands for better device power and battery management, this paper investigates some factors that can impact the power consumption on the energy consumption of mobile devices. The focus is on two factors when performing multimedia streaming: the impact of the traffic location within a WLAN; and the impact of the radio access network technology (WLAN, HSDPA, UMTS). The energy measurement results show that by changing the quality level of the multimedia stream the energy can be greatly conserved while the user perceived quality level is still acceptable. Moreover, by using the cellular interface much more energy is consumed (up to 61%) than by using the WLAN interface.