Farhan Siddiqui

Mobility management across hybrid wireless networks: Trends and challenges

Future generation wireless networks are envisioned to be a combination of diverse but complementary access technologies. Internetworking these types of networks will provide mobile users with ubiquitous connectivity across a wide range of networking environments. The integration of existing and emerging heterogeneous wireless networks requires the design of intelligent handoff and location management schemes to enable mobile users to switch network access and experience uninterrupted service continuity anywhere, anytime. Real deployment of such mobility strategies remains a significant challenge. In this article, we focus on handoff management. We discuss in detail handoff decision and implementation procedures and present recent handoff techniques that aim at providing mobility over a wide range of access technologies. We also discuss some of the capabilities of mobile terminals that are necessary to implement seamless mobility over hybrid wireless networks. Furthermore, we also present and discuss limitations of recent handoff design architectures and protocols as well as outstanding challenges that still need to be addressed to achieve portable and scalable handoff solutions for continuous connectivity across wireless access networks.

Internet Protocol Television (IPTV): Architecture, Trends, and Challenges

Internet protocol television (IPTV), a technology that delivers video content over a network that uses the IP networking protocol, has been receiving a lot of attention over the last couple of years. The increasing interest in IPTV is being driven by remarkable advances in digital technologies and consumer electronic devices, broadband networking technologies, Web services, as well as more entertainment demands (enabled by decreasing costs of hardware and software technologies) from both consumers and content providers. In this paper, we briefly discuss IPTV standardization initiatives and present the design of both next-generation network (NGN)-based and non-NGN-based architectures that have been recently proposed to enable the deployment of IPTV. In addition, we describe the challenges and solutions associated with mobile IPTV and peer-to-peer IPTV systems. We Anally present some IPTV trends and identify some of the IPTV challenges that must be addressed to enable the ubiquitous deployment and adoption of IPTV.

An Empirical Analysis of Handoff Performance for SIP, Mobile IP, and SCTP Protocols

Over the last decade, we have witnessed a growing interest in the design and deployment of various network architectures and protocols aimed at supporting mobile users as they move across different types of networks. One of the goals of these emerging network solutions is to provide uninterrupted, seamless connectivity to mobile users giving them the ability to access information anywhere, anytime. Handoff management, an important component of mobility management, is crucial in enabling such seamless mobility across heterogeneous network infrastructures. In this work, we investigate the handoff performance of three of the most widely used mobility protocols namely, Mobile IP, Session Initiation Protocol (SIP), and Stream Control Transmission Protocol (SCTP). Our empirical handoff tests were executed on an actual heterogeneous network testbed consisting of wired, wireless local area, and cellular networks using performance metrics such as handoff delay and handoff signaling time. Our empirical results reveal that Mobile IP yields the highest handoff delay among the three mobility protocols. In addition, we also found that SIP and SCTP yield 33 and 55% lower handoff delays respectively compared to Mobile IP.

Smart Grid Privacy: Issues and Solutions

Migration to an electronically controlled electrical grid to transmit, distribute, and deliver power to consumers has helped enhance the reliability and efficiency of conventional electricity systems. At the same time, this digitally enabled technology called the Smart Grid has brought new challenges to businesses and consumers alike. A key component of such a grid is the smart-metering technology, which is used to collect energy consumption data from homes and transmitting it back to power distributors. A crucial concern is the privacy related to the collection and use of energy consumption data. We present an analysis of Smart Grid privacy issues and discuss recently proposed solutions that can protect the privacy of Smart Grid users.

Design and implementation of a SIP-based VoIP architecture

The emergence of the session initiation protocol (SIP) promises simple and efficient handling of multimedia sessions among multiple users. We present the design and implementation of a VoIP system based on SIP. Our SIP-based VoIP system provides a wide range of services multipoint call, multiple audio encoding formats, and complex functionalities such as call muting and call-hold facilities, and personal mobility support.

SCTP multihoming support for handoffs across heterogeneous networks

Next-generation mobile terminals are expected to provide users with seamless, uninterrupted network connectivity while moving across wide geographic locations. Achieving continuous network access is made possible by exploiting multihoming in mobile nodes and providing support for several heterogeneous network interfaces. Efficient mechanisms are required to enable mobile nodes to connect to various available networks to improve connectivity and provide network resilience. Stream control transmission protocol (SCTP) has been proposed as a potential candidate for facilitating multiple network support to achieve smooth session continuity while moving across different types of networks. This paper analyses the design and performance of proposed SCTP implementations for multihoming purposes. We present an empirical evaluation of SCTP while performing handoffs by conducting experiments in a real multi-network environment. We also identify the benefits and limitations of user and kernel-level implementations of SCTP

Gigabit Wireless Networking with IEEE 802.11ac:Technical Overview and Challenges

The ever-growing proliferation of wireless devices and concurrent deployments of bandwidth intensive applications has been having a significant impact on user experience in high-density wireless areas. IEEE 802.11ac is a recently ratified Wireless Local Area Network (WLAN) standard that promises to improve wireless user experience by delivering gigabit speed to end-user applications. 802.11ac utilizes new technologies such as Channel Bonding, Beamforming, and Multi-User Multiple-Input Multiple-Output (MU-MIMO) to improve wireless performance. This article reviews recent technological advances made in the field of WLANs and then focuses on the recent IEEE 802.11ac standard. We present actual data rates attained by currently available 802.11ac hardware, and we also discuss foreseen technical challenges that still need to be addressed to enable efficient and seamless gigabit wireless networking

QoS path selection exploiting minimum link delays in MPLS-based networks

Real-time multimedia is typically associated with various quality of service (QoS) requirements. Several QoS routing schemes have been proposed to determine a path which has sufficient bandwidth to achieve the desired QoS requirements. Some of these schemes flood nodes with advertisements to obtain information about congestion on the links. Consequently, protocol overhead is of concern in such cases. Other schemes use source routing to determine the shortest routing path, but security is a major concern for allowing source routing in the Internet. To efficiently support QoS over IP networks, traffic engineering (TE) has introduced multiprotocol label switching (MPLS). QoS routing is an essential component of MPLS to maximize network resources. In this paper, we propose an approach that sets up a label switched path (LSP) based on the lowest time delay from the ingress to the egress router using only the ingress, rather than requiring all the nodes in the network to exchange information. Our simulation results show that with our proposed approach, we obtain an improvement in the number of packets delivered and better use of network resources. Furthermore, modification of the MPLS domain is not required.

A dynamic network discovery and selection method for heterogeneous wireless networks

Next generation communication systems aim at providing ubiquitous network access by integrating a wide-range of wireless technologies. The availability of various access networks requires a mobile device to be capable of selecting the best access network with minimum user intervention. We present a design architecture that efficiently discovers available wireless networks, and implements automatic network selection based on several factors such as the conditions of accessible networks, requirements of active applications, and preferences of the mobile user. We also present a case study to demonstrate the operation of the proposed prototype architecture in an actual heterogeneous network testbed.

Energy Efficient Routing in Wireless Sensor Networks

Recently, Wireless Sensor Networks (WSNs) have attracted lot of attention due to their pervasive nature and deployment in many real world applications. Sensor nodes are scattered in the environment to sense and send the specified data back to the desired users. To achieve this goal, we need an efficient and scalable routing protocol that can select the most optimal routes between the sensor nodes and users who are normally far away. Since sensor nodes need to be embedded in the environment they tend to be very small with low processing and memory and have small battery sizes. To prolong the lifetime of the network and wireless sensor nodes, an important requirement of wireless sensor routing protocols is their energy-efficiency. We review recent energy-efficient wireless sensor routing protocols, which have been proposed recently in the literature and evaluate them using a comprehensive taxonomy.