Showing papers by "Mohsen Guizani published in 2007"

An effective key management scheme for heterogeneous sensor networks

Abstract: Security is critical for sensor networks used in military, homeland security and other hostile environments. Previous research on sensor network security mainly considers homogeneous sensor networks. Research has shown that homogeneous ad hoc networks have poor performance and scalability. Furthermore, many security schemes designed for homogeneous sensor networks suffer from high communication overhead, computation overhead, and/or high storage requirement. Recently deployed sensor network systems are increasingly following heterogeneous designs. Key management is an essential cryptographic primitive to provide other security operations. In this paper, we present an effective key management scheme that takes advantage of the powerful high-end sensors in heterogeneous sensor networks. The performance evaluation and security analysis show that the key management scheme provides better security with low complexity and significant reduction on storage requirement, compared with existing key management schemes.

Two Tier Secure Routing Protocol for Heterogeneous Sensor Networks

Abstract: Research on sensor network routing focused on efficiency and effectiveness of data dissemination. Few of them considered security issues during the design time of a routing protocol. Furthermore, previous research on sensor networks mainly considered homogeneous sensor networks where all sensor nodes have the same capabilities. It has been shown that homogeneous ad hoc networks have poor fundamental performance limits and scalability. To achieve better performance, we adopt a heterogeneous sensor network (HSN) model. In this paper, we present a secure and efficient routing protocol for HSNs - two tier secure routing (TTSR). TTSR takes advantage of powerful high-end sensors in an HSN. Our security analysis demonstrates that TTSR can defend typical attacks on sensor routing. Our performance evaluation shows that TTSR has higher delivery ratio, lower end-to-end delay and energy consumption than a popular sensor network routing protocol.

IEEE 802.20: mobile broadband wireless access

Abstract: This article provides a survey of the emerging IEEE 802.20 standard, also known as mobile broadband wireless access. It provides an introduction to the activities with regard to this standard, including purpose and scope that the specification defines. The relationship with other similar standards such as IEEE 802.16e and 3G are discussed as well. Various technical details of the standard are presented, including quality of service parameters, data rates available to end users, application support, and security. Characteristics that the air interface should provide, specifically in regard to the physical and medium access control layers, are detailed as well

Design of next-generation cdma using orthogonal complementary codes and offset stacked spreading

Abstract: This article presents an innovative code-division multiple access system architecture that is based on orthogonal complementary spreading codes and time-frequency domain spreading. The architecture has several advantages compared to conventional CDMA systems. Specifically, it offers multiple-access-interference-free operation in AWGN channels, reduces co-channel interference significantly, and has the potential for higher capacity and spectral efficiency than conventional CDMA systems. This is accomplished by using an "offset stacked" spreading modulation technique followed by quadrature amplitude modulation, which optimizes performance in a fading environment. This new spreading modulation scheme also simplifies the rate matching algorithms relevant for multimedia services and IP-based applications.

Pulse Waveform Dependent BER Analysis of a DS-CDMA UWB Radio Under Multiple Access and Multipath Interferences

Abstract: This paper proposes an approach to analyze pulse waveform dependent bit error rate (BER) performance of a DS-CDMA ultra wideband (UWB) radio, which operates in a frequency selective fading channel. The analysis takes into account almost all real operational conditions, such as asynchronous transmissions, RAKE receiver, multiple access interference (MAI), multipath interference (MI), log-normal shadowing, and noise. The main objective of the paper is to reveal the relationship between time domain characteristics of pulse waveforms and BER of a UWB radio. It is shown through analysis (also validated by simulation) that the normalized mean squared auto-correlation function (ACF) of the pulse waveforms can be used as an effective merit figure to judge the suitability for their applications in a DS-CDMA UWB radio. In fact, the normalized mean squared auto-correlation function (ACF) governs the average inter-chip interference caused by imperfect auto-correlation function of the pulse waveforms. The paper concludes that, as long as the power spectral density (PSD) functions of the pulse waveforms fit the FCC spectral mask, the pulse waveforms' normalized mean squared ACF should be minimized to ensure an acceptable BER.

A Pseudo-Random Function Based Key Management Scheme for Heterogeneous Sensor Networks

Abstract: Security is critical for sensor networks used in military, homeland security and other hostile environments. Previous research on sensor network security mainly considers homogeneous sensor networks, i.e., all sensor nodes are the same. Research has shown that homogeneous ad hoc networks have poor performance and scalability. Furthermore, many security schemes designed for homogeneous sensor networks have high communication overhead, computation overhead, and/or large storage requirement. To achieve better security and performance, we adopt a heterogeneous sensor network (HSN) model. In this paper, we present an efficient key management scheme that takes advantage of the powerful high-end sensors in HSN. The performance evaluation and security analysis show that the key management scheme provides better security with low complexity and significant reduction on storage requirement, compared to existing sensor key management schemes.

Wireless Broadband Access: WiMAX and Beyond [Guest Editorial]

Abstract: The three articles in this special section are devoted to wireless broadband communications, with special emphasis on WiMax and other new applications.

Security in wireless mobile ad hoc and sensor networks [Guest Editorial]

Abstract: The goal of this feature topic is to report recent advances in and significant contributions to all aspects of security in resource-constrained mobile ad hoc and sensor networks. Specific areas of interest include key management, secure communications, secure location discovery, secure clock synchronization, and intrusion detection.

A Secure Time Synchronization Scheme for Heterogeneous Sensor Networks

Abstract: Time synchronization is critical for many sensor network operations, such as mobile object tracking and sensor node scheduling. Many existing time synchronization schemes for sensor networks do not considering security issue, and they are vulnerable to several attacks. Furthermore, most existing synchronization schemes are designed for homogeneous sensor networks, where all sensors have the same capability. Research has shown that homogeneous ad hoc networks have poor fundamental limits and performance. To improve performance and security of sensor networks, we adopt a Heterogeneous Sensor Network (HSN) model. In this paper, we present a secure and efficient time synchronization scheme for HSN by utilizing powerful high-end sensors. We implement the synchronization scheme in real sensors and our experiments show that the scheme achieves high accuracy. The security analysis demonstrates that our scheme is resilient to various attacks.

Second-Order Rate-Control Based Transport Protocols Over Mobile Wireless Networks

Abstract: While TCP (transmission control protocol) is an efficient transport protocol in the wired Internet, it performs poorly when used in wireless environments. This is because TCP couples the error and flow control by using packet loss to infer the network congestion and thus the random loss in wireless Internet can inevitably mislead TCP dropping its flow-control window unnecessarily, even if the network is not congested at all. To overcome this problem, we propose the second-order rate-based flow control and the decoupled window-based error-control schemes for high-throughput transport protocols over the wireless networks. The second-order rate control minimizes congestive losses by using the explicit congestion notification (ECN)-bit feedback to adapt the rate-gain parameter to the variations of the round-trip time (RTT) and cross-traffic flows. The error-control scheme detects and selectively retransmits the lost packets caused by either congestion or random-noise/handoffs on wireless links, which is decoupled from the flow control such that the rate control is independent of the random loss of wireless links. Using the fluid analysis, we establish the rate-control model, and derive expressions for throughput, losses, and link-transmission efficiency. Through extensive simulations, the proposed transport protocol is shown to possess the TCP-compatibility in bandwidth while coexisting with TCP-Reno traffics in the wired Internet. Our simulations also verify the analysis, and demonstrate the significant superiority of our scheme to TCP in terms of increasing the average throughput over wireless links and the robustness to the variation of wireless random-loss probability while minimizing the losses and retransmissions.

Using MILP for Optimal Movement Planning in MANETs with Cooperative Mobility

Abstract: Rapid-deployment mobile ad-hoc networks (MANETs) are frequently characterized by common overarching mission objectives which make it reasonable to expect some degree of cooperativeness on the part of their constituent nodes. In this article we demonstrate new strategies to improve MANET communications, based on inter-node cooperation with respect to node mobility. We present our model for cooperative mobility, and use this cost-benefit framework to explore the impact of cooperation in MANETs where nodes are - to varying extents - willing to be moved for the common good. We develop a mixed-integer linear programming (MILP) formulation of the model, accurately capturing its objectives and constraints. The MILP model is evaluated through simulations and found to be very effective, albeit for small networks. To make the proposed technique scale to large networks we develop a new technique for converting a large global MILP into a sequence of smaller local MILP optimizations, and demonstrate that the resulting approach is scalable and succeeds at efficiently moving cooperative nodes in a manner which optimizes connection bit error rates.

Surrendering autonomy: can cooperative mobility help?

Abstract: In this paper, we develop a Cooperative Mobility Model that captures new salient features of collaborative and mission-oriented MANETs. In particular, the cost-benefit framework of our model is a significant advance in modelling heterogenous networks whose nodes exhibit the complete range of autonomy with respect to mobility. We then describe the design of CoopSim, a platform for conducting simulation experiments to evaluate the impact of parameter, policy and algorithm choices on any system based on the proposed Cooperative Mobility Model. We present a small but illustrative case study and use the experimental evidence derived from it to give an initial evaluation of the merits of the proposed model and the efficacy of the CoopSim software. In our case study, we propose studying the impact of the proposed model on improving the end-to-end communication based on the QoS parameter, namely BER.

Paging Schemes Performance for Wireless

Abstract: In this paper, we provide a performance evaluation for blanket paging scheme, sequential probability paging scheme, and pipeline probability paging scheme in wireless networks. Both analytical models and extensive simulations are adopted to study these schemes.

Wireless Communications Applications

Abstract: First page of article Keywords: wireless communications applications; third-generation standards

On Frequency Domain Doppler Diversity Using Basis Expansion Model and EM-Based Algorithms in CDMA Systems

Abstract: In this paper, we propose an algorithm for frequency domain adaptive Doppler shift estimation in the presence of multiple Doppler subpaths in DS-CDMA systems. By modeling doubly selective channel with a basis expansion model (BEM), the proposed method works based on expectation-maximization (EM) algorithm and can accurately estimate Doppler shifts. A complete Cramer-Rao lower bound (CRLB) analysis of the estimation algorithms is also provided.