Janise McNair

Mobility management in next-generation wireless systems

This paper describes current and proposed protocols for mobility management for public land mobile network (PLMN)-based networks, mobile Internet protocol (IP) wireless asynchronous transfer mode (ATM) and satellite networks. The integration of these networks will be discussed in the context of the next evolutionary step of wireless communication networks. First, a review is provided of location management algorithms for personal communication systems (PCS) implemented over a PLMN network. The latest protocol changes for location registration and handoff are investigated for mobile IP followed by a discussion of proposed protocols for wireless ATM and satellite networks. Finally, an outline of open problems to be addressed by the next generation of wireless network service is discussed.

Vertical handoffs in fourth-generation multinetwork environments

Revolutionary drivers for 4G include a push toward universal wireless access and ubiquitous computing through seamless personal and terminal mobility. One of the major challenges for seamless mobility is the criterion of a vertical handoff protocol: a handoff protocol for users that move between different types of networks. Traditional operations for handoff detection policies, decision metrics, and radio link transfer are not able to adapt to dynamic handoff criteria or react to user inputs and changing network availabilities. Nor are they able to deliver context-aware services or ensure network interoperability. Thus, new techniques are needed to manage user mobility between different types of networks. This article presents a tutorial on the design and performance issues for vertical hand-off in an envisioned multinetwork fourth-generation environment. Various network architectures and technologies for 3G and beyond are described, including wireless LANs, cellular, satellite, and Mobile IP. Then the problem of vertical handoff is defined in the context of such a diverse network environment. Finally, research efforts to resolve the open problems are explored, including new techniques for dynamic handoff decision and detection algorithms and context-aware radio link transfer.

Optimizations for vertical handoff decision algorithms

Future wireless networks must be able to coordinate services within a diverse network environment. One of the most challenging problems for coordination is vertical handoff, which is the decision for a mobile node to handoff between different types of networks. While traditional handoff is based on received signal strength comparisons, vertical handoff must evaluate additional factors, such as, monetary cost, offered services, network conditions, and user preferences. In this paper, several optimizations are proposed for the execution of vertical handoff decision algorithms, with the goal of maximizing the quality of service experienced by each user. First, the concept of policy-based handoffs is discussed. Then, a cost function is defined to judge target networks based on a variety of user- and network-valued metrics. Finally, a performance analysis demonstrates that significant gains in quality of service and a more efficient use of resources can he achieved from the proposed optimizations.

Medium access control protocols for multimedia traffic in wireless networks

This article presents a survey on medium access control protocols for multimedia traffic in wireless networks. A basic overview of MAC protocol concepts is presented, and a framework is developed on which to base qualitative comparisons. The MAC protocols covered include third-generation TDMA and CDMA schemes intended for use in a single-hop wireless system. The operation of each protocol is explained, and its advantages and disadvantages ore presented. Finally, a qualitative comparative outline of the discussed protocols is provided, based on multimedia traffic requirements.

Mobility management in current and future communications networks

This article describes current and proposed protocols for mobility management for public land mobile networks (PLMNs), Mobile IP, wireless ATM, and satellite networks. The integration of these networks is discussed in the context of the next evolutionary step of wireless communications networks. First, a review is provided of location management algorithms for PCS implemented over a PLMN. The latest protocol changes for location registration and handoff are investigated for Mobile IP, followed by a discussion of proposed protocols for wireless ATM and satellite networks. Finally, an outline of open problems to be addressed by the next generation of wireless network service is discussed.

An inter-system handoff technique for the IMT-2000 system

Next-generation wireless communication is based on a global system of fixed and wireless mobile services that are transportable across different network backbones, network service providers, and network geographical boundaries. One of the most important problems for global wireless service is handoff management. In this paper, a new handoff technique is introduced which supports mobility between dissimilar networks. First, the system architecture is described, based on the concept of a boundary cell region between networks. Then a new inter-system handoff protocol is presented that uses boundary cells that allow the mobile terminal to roam into a different network. The performance of the protocol is analyzed in terms of the additional inter-system handoff signaling time and the minimum boundary cell area threshold for a successful transition within the prescribed time constraints.

Multiservice vertical handoff decision algorithms

Future wireless networks must be able to coordinate services within a diverse-network environment. One of the challenging problems for coordination is vertical handoff, which is the decision for a mobile node to handoff between different types of networks. While traditional handoff is based on received signal strength comparisons, vertical handoff must evaluate additional factors, such as monetary cost, offered services, network conditions, and user preferences. In this paper, several optimizations are proposed for the execution of vertical handoff decision algorithms, with the goal of maximizing the quality of service experienced by each user. First, the concept of policy-based handoffs is discussed. Then, a multiservice vertical handoff decision algorithm (MUSE-VDA) and cost function are introduced to judge target networks based on a variety of user- and network-valued metrics. Finally, a performance analysis demonstrates that significant gains in the ability to satisfy user requests for multiple simultaneous services and a more efficient use of resources can be achieved from the MUSE-VDA optimizations.

Residual energy aware channel assignment in cognitive radio sensor networks

We investigate the channel assignment problem in a cluster-based multi-channel cognitive radio sensor network in this paper. Due to the inherent power and resource constraints of sensor networks, energy efficiency is the primary concern for network design. An R-coefficient is developed to estimate the predicted residual energy using sensor information (current residual energy and expected energy consumption) and channel conditions (primary user behavior). We examine three channel assignment approaches: Random pairing, Greedy channel search and Optimization-based channel assignment. The last two exploit R-coefficient to obtain a residual energy aware channel assignment solution. Simulation results show that R-coefficient-based approaches lead to better performance in terms of energy consumption and residual energy balance. Optimization-based channel assignment outperforms the other two approaches with respect to network lifetime.

Handoffs for real-time traffic in Mobile IP version 6 networks

Current commercial growth in wireless and mobile communications is being fueled by wireless Internet access and the promise of mobile multimedia applications. However, the delivery of such services depends on the ability of the mobile Internet to support real-time traffic flows with guaranteed quality of service (QoS). The current mobility protocol for the Internet, Mobile IP, was designed for best effort packet delivery, and, as a result of being based on IP version 4, has inefficient handoff routing procedures that limit its performance for real-time traffic. A new two-path handoff is proposed for Mobile IP networks that enables the Internet to support large-scale mobility while maintaining QoS guarantees for multimedia traffic. First, we discuss related work on Internet mobility. Then, we introduce the new two-path handoff technique, which incorporates IP version 6 and the integrated services (IntServ) QoS architecture. Finally, we compare the performance of our new technique with other proposed protocols for Mobile IP in terms of bandwidth use efficiency and handoff disruption times.

Secure probabilistic location verification in randomly deployed wireless sensor networks

Security plays an important role in the ability to deploy and retrieve trustworthy data from a wireless sensor network. Location verification is an effective defense against attacks which take advantage of a lack, or compromise, of location information. In this work, a secure probabilistic location verification method for randomly deployed dense sensor networks is proposed. The proposed Probabilistic Location Verification (PLV) algorithm leverages the probabilistic dependence of the number of hops a broadcast packet traverses to reach a destination and the Euclidean distance between the source and the destination. A small number of verifier nodes are used to determine the plausibility of the claimed location, which is represented by a real number between zero and one. Using the calculated plausibility metric, it is possible to create arbitrary number of trust levels in the location claimed. Simulation studies verify that the proposed solution provides high performance in face of various types of attacks.