Game Theory for Resource Allocation in Wireless Networks

Wireless technologies and devices are becoming increasingly ubiquitous in modern society. Wireless resources are natural and fixed, whereas wireless technologies and devices are increasing day-by-day, resulting in spectrum scarcity. As a consequence, efficient use of limited wireless resources has become an issue of vital importance in wireless systems. As demand increases, management of limited wireless resources for optimal allocation becomes crucial. Optimal allocation of limited wireless resources results in quick and reliable dissemination of information to larger service areas. Recently, game theory has emerged as an efficient tool to help optimally allocate wireless resources. Game theory is an optimization technique based on strategic situations and decision-making, and has found its application in numerous fields. The first part of this chapter presents a review of game theory and its application in resource allocation at different layers of the protocol stack of the network model. As shown by a recent study, static assignment of frequency spectrum by governmental bodies, such as FCC (Federal Communications Commission) in the United States, is inefficient since the licensed systems do not always fully utilize their frequency bands. In such a scenario, unlicensed secondary (cognitive radio) users can identify the idle spectrum bands and use them opportunistically. In order to access the licensed spectrum dynamically and opportunistically, the dynamic spectrum access functionality needs to be incorporated in the next generation (XG) wireless networks. Different game theory approaches for dynamic spectrum access are discussed in the second part of the chapter.

Body Area Networks

Nowadays, wireless Body Area Networks (wBAN) have gained more relevance, in particular in the areas of health care, emergencies, ranging, location, domotics and entertainment applications. Regulations and several wireless protocols and standards have appeared in recent years. Some of them, like Bluetooth, ZigBee, Ultra Wide Band (UWB), ECMA368, WiFi, GPRS and mobile applications offer different kinds of solutions for personal area communications. In this chapter, body area network channel modelling will be described; also, a brief description of the applications and state-of-the-art of regulation and standardization processes pertaining to these kinds of networks will be presented. For each topic, the chapter shows not only the main technical characteristics, but also the technical problems and challenges in recent and future research. Finally, the chapter provides an analysis of Body Area Networks, opinions about the future and possible scenarios in the short- and medium-term for the development of standards and applications and their impacts on our daily lives.

IP Mobility Support in Hybrid Wired-Mobile Ad Hoc Networks

Mobile ad hoc networks (MANETs) make use of a distributed routing mechanism to support connectivity between nodes within the ad hoc network. A wireless ad hoc network can be deployed for multiple applications, such as extending the coverage of wire based networks, where interworking is achieved via wireless access routers. However, the implementation of a hybrid (i.e. wired and wireless) network is not straightforward and several issues must be solved for these types of deployments to become a reality. One concern is related to terminal mobility while preserving ongoing communication sessions over IP networks; as a mobile node moves from one subnetwork to a new subnetwork, a mobility protocol (e.g. Mobile IP) is required for the mobile node to preserve a communication session without having to reestablish the session with a correspondent node. This issue is more complex in a hybrid network where the wireless domain is composed of a mobile ad hoc network (MANET). For instance, MANET routing protocols usually do not account for the connectivity toward a wired network, such as the Internet, via a single or multiple access routers. As a result, there are multiple routing issues that must be taken into consideration to support interconnectivity between nodes located in a hybrid network topology. The main contribution of this work is to present a review on the state of the art of IP mobility support for hybrid wired–MANETs and discuss some of the relevant issues in this area. In addition, two case studies are presented where macromobility (e.g. Mobile IP) and micromobility (Mobile-IP – HAWAII) protocols are implemented to support IP mobility on hybrid networks.

Connectivity and Topology Organization in Ad-Hoc Networks for Service Delivery

This chapter introduces the concept of connectivity and robustness of a mobile ad-hoc network as a function of the node density and coverage radius. It presents an elementary analytical model based on the spatial Poisson process to formulate the connectivity problem as the computation of the existence of wireless links forming paths obtained by Dijkstra’s shortest path algorithm. It also introduces a simple clustering strategy that starts forming groups based on one-hop distance and then adjust the coverage radius of the nodes in order to decrease the interference, processing load and isolated nodes in the network. It includes results of scenarios with different robustness of origin-destination pairs and number of clusters and shows the benefits of using the introduced policies.

Power Aware Routing in Wireless Mobile Ad Hoc Networks

Wireless mobile ad hoc networks are gaining importance because of their flexibility, mobility, and ability to work with a limited infrastructure. If the battery of a node is drained out, then it cannot communicate with other nodes and the number of dead nodes makes the network partition. In order to overcome the network partition problem, this chapter presents different routing algorithms for wireless mobile ad hoc networks. Different routing algorithms use different metrics, namely transmission power, residual battery capacity and noncritical nodes to forward data packets from the source to destination. Minimum total transmission power routing uses the transmission power as metric to forward the packets but it cannot increase the lifetimes of the node and network. In conditional max-min battery capacity routing, it increases network lifetime and reduces power consumption over the network. Noncritical nodes with more residual battery capacity based routing models will increase the network lifetime and network throughput.

Location Acquisition and Applications in Mobile and Ad-Hoc Environments

This chapter addresses the relevance of location information as an important resource that supports other applications. This information is important for better network planning, development of new location-based services, fast deployment of assistance services, and support of surveillance and safety regulations, among others. Accuracy of location acquisition processes is an important factor because the potential for multiple new location-based services depends on it. However, noise is always present at least in two forms. Measurements taken with electronic instruments are inherently noisy and estimation algorithms introduce noise of their own in the assumption process. For this reason, this chapter explores several methods and techniques. A well- balanced solution should take into account the compromise between accuracy and delay and/or complexity. Many solutions have been proposed for new needs and new applications which demand more timely and accurate position locations of users or objects.

Key Management Protocols in Mobile Ad Hoc Networks

Mobile ad hoc networks (MANETs) have received tremendous attention in recent years because of their self-organization and self-maintenance capabilities. MANETs are networks that do not have an underlying fixed infrastructure. However, these networks tend to be vulnerable to a number of attacks. They don’t obey a centralized network management functionality; furthermore, the network topology changes dynamically. Therefore, security has become a primary concern in MANETs. The major problem in providing security services in such networks is how to manage cryptography keys, making key management a central component in MANETs. This chapter gives an overview of security in this kind of network and presents a number of MANETs key management protocols according to recent literature.

A Forward & Backward Secure Key Management in Wireless Sensor Networks for PCS/SCADA

Process Control Systems (PCSs) or Supervisory Control and Data Acquisition (SCADA) systems have recently been added to the already wide collection of wireless sensor network applications. The PCS/ SCADA environment is somewhat more amenable to the use of heavy cryptographic mechanisms such as public key cryptography than other sensor application environments. The sensor nodes in this environment, however, are still open to devastating attacks such as node capture, which makes the design of secure key management challenging. This chapter introduces an adversary model with which we can assess key management protocols. It also proposes a key management scheme to defeat node capture attack by offering both forward and backward secrecies. The scheme overcomes the pitfalls of a comparative scheme while being not computationally more expensive.

Low Power Design Techniques for Wireless Sensor Networks

WSNs can be applied in several areas for the monitoring and control of variables. In the design process of a WSN, one of the most important design objectives is to minimize the energy required for sensing, signal processing and communication tasks to extend the lifetime of the network. This chapter discusses a broad variety of schemes used to reduce power consumption in WSNs. The design of sensors nodes involves several core aspects, such as supported sensors, the communication interface, applications, the control system and peripherals. Strategies to preserve the energy used by each of these components are discussed. A specific scheme using digital signal processing to reduce power consumption by decreasing the number of transmissions is proposed. The chapter also considers protocol architectures, focusing on link layer, network layer, and cross-layer approaches. Finally, a comparative analysis among the main techniques is presented.

A Survey on Localization in Wireless Sensor Networks

Localization is a fundamental challenge of wireless sensor networks in many applications because a set of nodes must be aware of individual positions, based only on their own resources, i.e. without the aid of external agents. This problem has been tackled using different approaches that provide good solutions under specific circumstances. Nevertheless, new conditions, including massive node deployment or irregular topologies, call for further study and development.