Wireless Body Area Networks (WBANs) have the potential for extensive use in health care monitoring. To provide optimum network utilization, it is important to efficiently schedule multiple co-existing WBANs which could possibly suffer from high degree of interference. A graceful coexistence can be feasible by appropriately scheduling transmissions from different WBANs. In this paper, we use a recent standard of IEEE 802.15.6 (TG6), which has been finalized in May 2012, to address the problems of intra and inter-WBAN interference. This standard offers several advantages for medical applications as compared to IEEE 802.15.4 which has been previously adopted for numerous healthcare applications. In this paper, we propose a QoS based MAC scheduling approach to avoid inter-WBAN interference and introduce a fuzzy inference engine for intra-WBAN scheduling so as to avoid interference within WBANs.

ABSTRACT With recent advances in wireless networking and in low‐power sensor technology, wireless sensor networks (WSNs) have taken significant roles in various applications. Whereas some WSNs only require minimal bandwidth, newer applications operate with a noticeably larger amount of data. One way to deal with these applications is to maximize the available capacity by utilizing multiple wireless channels. We propose DynaChannAl, a distributed dynamic wireless channel allocation algorithm that effectively distributes nodes to multiple wireless channels in WSNs. Specifically, DynaChannAl targets applications where mobile nodes connect to preexisting wireless backbones and takes the expected end‐to‐end queuing delay as its core metric. We used the link quality indicator values provided by 802.15.4 radios to whitelist high‐quality links and evaluate these links with the aggregated queuing latency, making it useful for applications that require minimal end‐to‐end delay (i.e., health care). DynaChannAl is a lightweight and adoptable scheme that can be incorporated easily with predeveloped systems. As the first study to consider end‐to‐end latency as the core metric for channel allocation in WSNs, we evaluate DynaChannAl on a 45 node test bed and show that DynaChannAl successfully distributes source nodes to different channels and enables them to select channels and links that minimizes the end‐to‐end latency. Copyright © 2012 John Wiley & Sons, Ltd.

In this paper we present a design of a medium access control protocol that allows the utilization of unused licensed spectrum of deployed wireless cellular systems (Primary System) by an overlaid multi-hop ad hoc network (Secondary System). The basic design principle is that the secondary operates in a non-intrusive manner and does not interact with the primary. We address a number of architectural challenges pertinent to this networking environment, and evaluate the performance of the MAC. Our performance evaluation results show that, in a single-hop ad hoc network, the proposed MAC transparently utilizes 75% of the bandwidth left unused by the primary, while, in the multi-hop cases, due to spatial reuse, the bandwidth utilization can be significantly higher.

The problems of energy efficient sensor network configuration and local fusion of sensed data have been addressed separately in the previous works. In this paper, we propose to analyze the sensing accuracy with the consideration of the node distribution and fusion overhead in terms of the energy consumption. By extending existing sensing model in the literature, we quantify how the sensing ranges and node densities of sensor nodes impact the sensing accuracy, and how it affects the fusion overhead and the sensing lifetime of the network. We identify the tradeoff between sensing accuracy and energy consumption in an analytical framework. It can be used to choose optimal parameters of sensor networks to meet the specified sensing or lifetime requirements.

In this paper we propose a cross-layer design for IEEE 802.15.4 MAC protocol that is based on a distributed backoff strategy governed by the wireless link quality measurements which are part of the standard. Our performance evaluation indicates that our scheme is more effective, achieving up to 69% higher goodput, and more efficient, delivering up to 154% more data bits per unit of energy consumed in the network, at the expense of an up to 18% degradation in fairness, compared to the basic 802.15.4.

In this paper we present a design of multi-channel medium access control protocol that allows the utilization of unused licensed spectrum of deployed wireless cellular systems (Primary System) by an overlaid multi-hop ad hoc network (Secondary System). The basic design principle is that the secondary operates in a non-intrusive manner and does not interact with the primary. We address a number of architectural challenges pertinent to this networking environment, and evaluate the performance of the MAC. Our performance evaluation results show that, in a single-hop ad hoc network, the proposed MAC transparently utilizes 75% of the bandwidth left unused by the primary, while, in the multi-hop cases, due to spatial reuse, the bandwidth utilization can be significantly higher.

The potential for rapid and infrastructure-less deployment in harsh geographic terrain as well as in conference-room like scenarios has propelled research on wireless ad hoc networks (MANETs). However, these networks are vulnerable to attackers due to certain inherently vulnerable characteristics. With intrusion prevention measures not guaranteed to work all the time, the need to constantly monitor what is going on in a system and look for intrusions is fulfilled by intrusion detection systems (IDS). In this paper we have proposed a novel and robust IDS for MANETs that aims to combine misuse with anomaly detection. Our protocol-independent design makes use of a self-adjusting threshold scheme that detects a priori known attack patterns with over 90% accuracy and is generally insensitive to false alarms. Experimental results indicate the non-degradability of network performance when our IDS is incorporated in the routing algorithm for security enhancements.

Abstract Wireless mobile ad hoc networks consist of mobile nodes interconnected by wireless multi‐hop communication paths. Unlike conventional wireless networks, ad hoc networks have no fixed network infrastructure or administrative support. The topology of such networks changes dynamically as mobile nodes join or depart the network or radio links between nodes become unusable. Supporting appropriate quality of service for mobile ad hoc networks is a complex and difficult issue because of the dynamic nature of the network topology and generally imprecise network state information, and has become an intensely active area of research in the last few years. This paper This article, except for some minor changes, is essentially the same as one that appears in 103 . The latter is a revised and updated version of 51 presents the basic concepts of quality of service support in ad hoc networks forunicastcommunication, reviews the major areas of current research and results, and addresses some new issues. The principal focus is on routing and security issues associated with quality of service support. The paper concludes with some observations on the open areas for further investigation. Copyright © 2004 John Wiley & Sons, Ltd.

Abstract Scalability of algorithms used in wireless sensor networks is a critical issue due to the extremely high node numbers and relatively high node density. Few recent studies analyze the scalability of algorithms in wireless ad‐hoc networks. Yet there is no significant research done on scalability of algorithms used in wireless sensor networks. In this paper, we present a brief survey of recent research on scalability of protocols for wireless ad‐hoc networks followed by a scalability analysis of a typical cross‐layer scheduling scheme used to improve energy efficiency in wireless sensor networks. Results show severe degradations of per‐node and per‐flow throughput indicating that such scheduling algorithms used in wireless sensor networks are far less scalable than the algorithms used in their ad‐hoc counterparts. Copyright © 2004 John Wiley & Sons, Ltd.

Among the factors, which can affect the quality of service of the four different levels of the traffic classes differentiated by their sensitivity to the delay tolerance, signaling ranks on the top. There is significant signaling messaging activity in UMTS among core network elements, and between SGSN and UTRAN that needs to be characterized so that its impact on the application architecture could be determined, and appropriate hardware and service software architectures to support signaling could be developed. Signaling affects mobility management, session management, call setup, and teardown times, etc. thus affecting the QoS of applications. In this paper we first examine the resulting signaling load on a core and a radio access networks for a given traffic penetration in the packet domain by considering a signaling procedure "Attach" and then analytically compute the throughput and the latencies for other basic signaling procedures such as Detach, and the PDF context activation in addition to attach by considering a platform which can act as a signaling server for the RNC, the SGSN, and the GGSN.

Algorithm-based fault tolerance (ABFT) is a technique to provide system level error detection and correction on array processors as well as multiprocessors at a low cost. Since the early 1980s the technique has been extensively applied to several linear algebraic algorithms, e.g., matrix multiplication, Gaussian elimination, QR factorization, and singular value decompositions, etc. An important class of problems in numerical linear algebra dealing with the iterative solution of linear algebraic equations arising due to the finite difference discretization or the finite element discretization of a partial differential equation, however, has been overlooked. The only exception is the recent application of algorithm based error detection (ABED) encodings to the successive overrelaxation algorithm for Laplace's equation. In this paper, ABED is applied to a multigrid algorithm for the iterative solution of a Poisson equation in two dimensions. Invariants are created to implement checking in the relaxation, the restriction, and the interpolation operators. Modifications to invariants due to roundoff errors accumulated within the operators, which often lead to a situation known as false alarms, have been addressed by deriving the expressions for the roundoff errors in the algebraic processes in the operators and correcting the invariants accordingly. The ABED encoded multigrid algorithm is shown to be insensitive to the size and the range of the input data besides providing excellent error coverage at a low latency for floating-point, integer, and memory errors.

Future surveillance operations will require easily deployable "microsensors" that are capable of autonomous detection and identification of objects. These devices will operate under severe limitations on energy consumption, to enable battery-powered operation. They will assess sensor inputs locally, transmitting data only after objects of interest have been detected and extracted from sensor data. This paper describes a prototype system that detects and tracks moving objects in image sequences obtained from an infrared video camera. Computation in the system is distributed across an FPGA and a DSP chip. The current system analyzes input images, in search of objects that meet predefined criteria. If these criteria are met, the system extracts a sub-image (or "chip") that contains an object of interest, and then transmits that to a central site for manual review and further analysis.

Major R&D activities are underway following the FCC rulings for the Wireless E-911 service. The goal is to determine the location of an emergency caller accurately, thus enhancing significantly the security of subscribers. Additional new applications include highway navigation and location sensitive billing, among others. Much of the research is focused on attaining a balance between location accuracy on one hand, and the cost on the other. We present an architecture for an efficient and cost effective wireless position location system using differential GPS with the GPRS of the GSM as the basic wireless infrastructure.

This paper presents a method for scaling switching system software for a given performance objective. Specifics are provided on scaling the existing switching system to a much larger system by preserving the same software architecture. We include results which have been obtained using the proposed algorithm on an actual switching system.