Zara Hamid

A hybrid routing protocol for wireless sensor networks with mobile sinks

Low power and lossy networks have been an active area of research due to their large number of potential applications in different environments like health, environment monitoring and entertainment domain. Numbers of protocols have been proposed for routing in these networks using metrics like hop count, delay, bandwidth etc. The working group of IETF has done one major contribution in form of a proactive gradient based routing protocol for low power and lossy networks (RPL). However, for a network having few mobile sinks calculating gradients using proactive approach is costly in terms of energy. This paper proposes a hybrid routing protocol for wireless sensor networks with mobile sinks. It proposes a combination of reactive and proactive approach to enhance RPL for efficiently handling movement of multiple sinks. DAGs are only maintained by nodes close to the sink within a certain zone. While the nodes outside the zone use on demand sink discovery to find the closest possible sink, without maintaining DAG. The frequency of zone creation messages and zone sizes can increase or decrease depending on the speed of sink. This helps to decrease the number of retransmissions resulting in low standing cost for maintain DAGs and enhances the network life time especially under average or high mobility of sink.

Mobility management challenges and issues in 4G heterogeneous networks

Mobility is one of the most invigorating features, having an enormous impact on how communication is evolving into the future. Mobility in 4G networks requires new level of mobility support as compared to traditional mobility. There is plenty of related research on mobility in next generation networks, which promises support for emerging ambient and ubiquitous communications. This paper aims to identify and explore the different issues and challenges related to mobility management in 4G heterogeneous networks. A review of the existing solutions and ongoing projects related to these mobility management issues is presented; which can help in discovering a unified approach to seamless mobility in future generation networks.

QoS in Wireless Multimedia Sensor Networks: A Layered and Cross-Layered Approach

The emergence of wireless multimedia sensor networks (WMSN) has given birth to several civilian as well as defense applications. Some of the interesting applications employing low cost sensor nodes to manipulate rich multimedia content include traffic monitoring, border surveillance, smart homes, environment and habitat monitoring. Unlike the traditional sensor networks which are aimed at maximizing network lifetime by decreasing energy utilization, the main objective of WMSNs is optimized delivery of multimedia content along with energy efficiency. Multimedia communications in WMSNs, has stringent delay and high bandwidth requirement as compared to scalar data transfer in WSNs. Fulfilling these constraints in resource and energy constrained WMSNs is a huge challenge. In WMSNs, each layer of the protocol stack is responsible and fully involved in providing QoS guarantees. There is a need for new schemes at each layer of the protocol stack- from advanced coding techniques that reduce encoder complexity and achieve maximum compression to dynamic routing and MAC protocols that provide service differentiation and reduce end-to-end latency. In wireless sensor networks, where all layers have dependency on each other, QoS guarantees are possible through the cross layer interaction of different layers. This paper gives an overview of the different existing layered schemes in WMSNs, followed by a discussion on the significance and efficiency gains that can be achieved from cross layer interactions in WMSNs along with the review of the existing cross layer approaches. Finally, we identify the open research issues which have not been adequately addressed so far.

XL-WMSN: cross-layer quality of service protocol for wireless multimedia sensor networks

Energy conservation has been the prime motivation behind the design of conventional protocols for wireless sensor networks (WSNs). However, recent trends toward high data rate multimedia communication over WSNs demand traffic- and deadline-aware content delivery with minimum energy expenditure. The basic quality of service requirement in wireless multimedia sensor networks (WMSNs) is time-bound data delivery. The conventional-layered protocol design solutions are inefficient, as real-time content delivery requires interactions between multiple layers like application for traffic categorization, network for real-time delivery, and media access control (MAC) for prioritized medium access with minimum energy expenditure. In this paper a cross-layer solution (XL-WMSN) is proposed for real-time data delivery. The XL-WMSN provides interaction between energy-based admission control, delay- and interference-aware routing, and dynamic duty cycle assignment at MAC layer. Simulation analysis shows that XL-WMSN increases the probability of delivering multimedia content within their allocated deadline and is more efficient than existing solutions.

An Augmented Security Protocol for WirelessMAN Mesh Networks

IEEE standard 802.16 is a broadband wireless access technology in wireless metropolitan access network (WMAN). It promises to provide wireless broadband access to homes, businesses and core telecommunication networks worldwide. Security is a critical concern to the success of IEEE standard 802.16. There has been extensive work on improving the security of IEEE standard 802.16 for both fixed and mobile networks in PMP mode, but thus far there is scarcity of research on security in IEEE 802.16 mesh mode. This paper presents a synopsis of the IEEE 802.16 mesh topology, overviews its security architecture and analyzes weaknesses in the existing privacy and key management protocol. It proposes an augmented privacy and key management (APKM) protocol that provides defense against the security threats present in a wireless environment

Cross -layer QoS routing protocol for Multimedia communications in Sensor Networks

Wireless Multimedia Sensor Networks (WMSN) are new and emerging networks of wirelessly connected devices, which consist of cameras, microphones, infra-red sensors, scalar sensors and others. These networks are fast gaining popularity due to their potential to be incorporated in various applications, such as, traffic monitoring, border surveillance, smart homes, environment and habitat monitoring, to retrieve heterogeneous data from the environment. However, these networks present many challenges as they are highly sensitive to delay and errors. The paper presents a Cross-layer QoS Routing protocol for WMSNs (CR-WMSN) that is aimed at providing soft end-to-end delay guarantees. Evaluation of this protocol shows that it provides better delay guarantees as compared to minimum hop routing protocol.

Delay and link utilization aware routing protocol for wireless multimedia sensor networks

Wireless Multimedia Sensor Networks (WMSNs) consist of networks of interconnected devices involved in retrieving multimedia content, such as, video, audio, acoustic, and scalar data, from the environment. The goal of these networks is optimized delivery of multimedia content based on quality of service (QoS) parameters, such as delay, jitter and distortion. In multimedia communications each packet has strict playout deadlines, thus late arriving packets and lost packets are treated equally. It is a challenging task to guarantee soft delay deadlines along with energy minimization, in resource constrained, high data rate WMSNs. Conventional layered approach does not provide optimal solution for guaranteeing soft delay deadlines due to the large amount of overhead involved at each layer. Cross layer approach is fast gaining popularity, due to its ability to exploit the interdependence between different layers, to guarantee QoS constraints like latency, distortion, reliability, throughput and error rate. The paper presents a channel utilization and delay aware routing (CUDAR) protocol for WMSNs. This protocol is based on a cross-layer approach, which provides soft end-to-end delay guarantees along with efficient utilization of resources. Extensive simulation analysis of CUDAR shows that it provides better delay guarantees than existing protocols and consequently reduces jitter and distortion in WMSN communication.

Intelligent routing protocol for Multimedia Sensor networks

The increase in the usefulness of WSNs, have lead to the transmission of multimedia content over these networks. This has escorted to the concept of Wireless Multimedia Sensor networks (WMSNs). Due to resource constrained structure of WSNs, special attention is required to route data in these networks. In this paper, we propose a novel routing protocol for WMSNs which establishes paths on the basis of traffic load, hop count and node energy. The protocol aims to find completely or partially disjoint paths for routing multimedia traffic with relatively minimum distance. Simulation results have shown that the proposed protocol is capable of finding intelligent path such that it increases throughput and avoid creation of network holes near the sink.

Traffic-aware congestion control (TACC) for wireless multimedia sensor networks

Wireless multimedia sensor networks (WMSNs) have emerged as a revolutionary technology, that has shifted the focus of low power wireless sensor networks (WSNs). These networks are aimed at gathering and delivering both scalar and multimedia data from the environment. WMSNs inherit the miniature size, low power, low processing and short range wireless communication traits from WSNs. Addition of multimedia content in WMSNs demands fulfillment of various QoS parameters like low end-to-end delay, acceptable jitter rate, low packet loss rate and higher throughput. Over the past few years, considerable research efforts have been directed towards the fulfillment of these QoS requirements; by proposing new traffic-aware medium access and routing algorithms. However, the issues of rate adaptation and congestion control are still largely unexplored. Congestion in wireless networks is a major cause of packet loss resulting in degraded network performance. In WMSNs congestion is a common occurrence, due to the communication of high data rate, bursty video traffic over lossy wireless link. Therefore, it is critical to adjust the sending rate of source nodes based on network conditions. This work investigates the issue of rate adaptation and congestion control in WMSNs. A traffic-aware congestion control protocol (TACC) is proposed that operates on end-to-end principle at the transport layer. The proposed protocol uses burst loss information to detect congestion at the destination and directs source nodes to adjust reporting rate accordingly. The proposed protocol is evaluated using simulation analysis which shows significant improvement in terms of packet losses, end-to-end delay, packet delivery ratio and received picture quality.

Analysis of Co-Channel Interference in VANETs under Nakagami-m Fading

Vehicular networks have become one of the most anticipated technologies of the current century due to their application oriented nature. This paper adopts the cluster based approach to analytically model the implications of interference in Vehicular Ad-hoc Networks (VANETs). To be specific, we derive a closed form expression for packet error probability for co-channel interference under Nakagami-m fading channel. Impact of Nakagami-m shape factor on interference is also characterized in detail. We then derive an expression for antenna selection scheme and obtain noteworthy enhancement in performance of cluster. Extensive simulations are performed to validate our findings which clearly prove the practical significance of our analytical model.