Mohammad Haseeb Zafar

A Survey of Cluster-based Routing Schemes for Wireless Sensor Networks

In recent times, wireless sensor networks (WSNs) have become progressively more attractive and have found their way into a wide variety of applications and systems because of their low cost, self-organizing behavior, and sensing ability in harsh environments. A WSN is a collection of nodes organized into a network. Routing is a vital technology in WSNs and can be roughly divided into two categories: flat routing and hierarchical routing. In a flat routing topology, all nodes have identical functionality and carry out the same task in the network. Nodes in a hierarchical topology do different tasks in WSNs and are usually arranged into clusters. In this paper, a survey on cluster-based routing schemes for WSNs has been done and comparisons made on the basis of performance factors such as latency, scalability, and energy awareness. Strengths and limitations of each scheme are presented, and open issues that must be addressed in the design of cluster-based routing algorithms are discussed.

I-AODV: Infrastructure based Ad Hoc On-demand Distance Vector routing protocol for Vehicular Ad Hoc Networks

Researchers are showing more and more interest in the Vehicular Ad Hoc Networks (VANETs) as it is found the most suitable mean for road safety, effective monitoring and control of traffic and global connectivity at all times as desired currently and in the future ahead. VANETs do not face the energy resource constraint which makes them suitable for larger coverage and network life time. However, due to higher vehicle speeds, persistent issues regarding network topology arises leading to frequent link failures, stale routes, end to end delay and higher packet loss ratios. In this paper, performance of Ad Hoc On-demand Distance Vector (AODV) routing protocol has been optimized by introducing fixed roadside wireless nodes for data transmission in a VANET environment. The concept is based on the presence of such wireless nodes along the road sides in major cities in the world. The word infrastructure is used because these fixed nodes contribute in providing paths available most of the time; thereby a way of tackling the dynamic network topologies and link failures. Additional directional antennas are employed at the fixed wireless nodes to achieve Line Of Sight (LOS) communication between them. Significant improvements are shown based on key performance metrics of hop count, route discovery time, network control traffic, end to end delay, media access delay, data dropped and throughput.

Gunshot detection and localization using sensor networks

Acoustic sensors or sensor networks can be efficiently used to spot and observe targets of interest and have the ability to conclude the exact location of an object or event within the sensor networks coverage range. For the detection and spot estimation of shooter, the schemes of gunshot localization require one or more sensing technologies. In current situation the importance of counter sniper systems cannot be denied. An efficient counter sniper system that can provide immediate shooter location will provide many benefits to our security personnel. In this paper, the Time Difference Of Arrival (TDOA) of Shock Wave and Muzzle Blast is used to estimate the shooter location. The proposed design and algorithm was validated and shooter origin was resolute that was very close to theoretical values. The result shows that the scheme worked very fine and is capable of locating sniper fires very efficiently, competently and effectively. The designed algorithm worked very well and results were found to be very accurately.

Comparison of clustering routing protocols for Wireless Sensor Networks

Nowadays, Wireless Sensor Networks (WSNs) has become progressively more attractive and has found its way into a wide variety of applications and systems because of its low-cost, self-organizing behavior and sensing ability in harsh environments. A WSN is a set of nodes arranged into a network. Routing is a vital technology in WSNs. It can be split into two groups namely flat routing and hierarchical routing. In flat routing all nodes have identical functionality and carry out the same task in the network. Whereas, nodes in a hierarchical routing have dissimilar duties and are usually arranged into clusters. This paper focuses on key clustering routing schemes for WSNs. We present a detailed comparison with simulations on NS-2 of LEACH, LEACH-C and PEGASIS and we deduce the performance of each with varying different parameters. It is evident from the simulation results that LEACH-C and PEGASIS outperform LEACH with respect to a number of key performance metrics.

Effects of HPA nonlinearities mitigation for amplitude, phase and their joint distortions using MIMO communication systems

Nonlinearities play an imperative role in performance of wireless communication systems. In this paper, High Power Amplifiers (HPA) have been used to check the performance of the proposed system by analyzing its amplitude, phase and their joint distortions using Multiple-Input Multiple-Output (MIMO) wireless communication system. This paper takes-in account the overall effects of HPA that provokes nonlinearities at the transmitters end in a communication system. Therefore, a novel method for the HPA nonlinearities mitigation has been proposed to improve the performance of amplitude, phase and joint distortions in MIMO communication systems. The simulation results show an improvement in the overall effect of the MIMO system and enhance the input response on the transmitter side. Furthermore, this method has been proposed to exploit the benefits of the MIMO system to improve the Symbol Error Rate (SER) versus Signal to Noise Ratio (SNR) curves for amplitude, phase and their joint distortions.

Hybrid routing scheme for Vehicular Delay Tolerant Networks

In Vehicular Delay Tolerant Networks (VDTN) connection from source to destination at any required period is not necessarily available. Therefore, the node with the message, save it in its own buffer and carry it until an opportunity comes across for forwarding. Fix nodes enhances the performance of VDTN. It helps in message storage and relaying messages. Due to mobility the bit error rate is high in mobile nodes connection but it is not considered in any of the previous routing schemes for VDTN. The connection between fix nodes will always have low bit error rate as compared to connection involving mobile nodes. All the pervious schemes are one dimensional. Environmental hindrances are not taken under consideration as well. Its effect can be both negative and positive. In this paper, a scheme titled Hybrid routing scheme is suggested to overcome the above stated problems. Features of another vehicular network called Vehicular Ad Hoc Networks (VANETs) are added to Maximum Priority (MaxProp) routing scheme for VDTN. Different propagation models of VANETs are implemented for both with and without mobile node communication for VDTN. The concept of bit error rate is also featured in Hybrid routing scheme. This makes Hybrid routing scheme two dimensional and more intelligent. The implementation and performance assessment of the proposed scheme is evaluated via Opportunistic Network Environment (ONE) Simulator. The Hybrid routing scheme outperform MaxProp in terms of the delivery probability and delivery delay.

Social interest-based routing in Delay tolerant networks

Internet is one of the basic requirements of the current age. Rural areas, particularly in the developing countries, do not have access to internet. Infrastructure based communication is very expensive, which makes it infeasible for the inhabitants of the backward areas. The presence of sparse nodes in the rural areas compared with urban areas decreases the chances of interaction among nodes. This can result in communication delay. In this paper, we propose a social interest based routing scheme that incorporates user interest into working movement model for delivery of data. Leveraging the diversity of interest in bus movement and placing the Throw box in the evening activity places in the working movement model, the proposed scheme achieves higher delivery probability. The simulation results show the effectiveness of the proposed scheme since delivery probability as high as 0.81 is attained. Furthermore, average cost and average latency is also improved.

HPA nonlinearities mitigation by joint predistorter and constellation rotation using MIMO communication systems

Nonlinearities in wireless communication channels foil the performance of the communication systems either at the transmitter or receiver end. This paper explains the concept of the transmitter-side nonlinearities that are induced by the High Power Amplifiers (HPA), the final stage at the transmitter side of the communication system. HPA nonlinearities create in-band and out-of-band distortions in wireless communication systems. The in-band distortion results in the degradation of overall performance of Bit Error Rate (BER) and the capacity of the mobile operations. On the other hand, out-of-band distortion creates the spectral broadening effects that degrade the performance of other operators usually operate in the near bands. This paper presents a novel method for the mitigation of HPA nonlinearities by joint predistorter and constellation rotation in Multiple-Input Multiple-Output (MIMO) wireless communication systems. The results reveal that the joint nonlinearity compensation technique in MIMO communications system enhances the overall error rate performance of the system. Furthermore to exploit the benefits of proposed technique; Symbol Error Rate (SER) curves for the MIMO multiplexing and Alamouti Space Time Block Codes (STBC) are presented with improvements in their signal to noise ratio.

Point-of-interests based best path selection using cluster-based routing

With the rapid introduction of new and innovative applications for handheld and On-board navigation devices and evolution in their hardware capabilities, the need for efficient and convenient resource provision for users arises. We propose user preferred optimal path route selection algorithm incorporating POIs or point of interests (POIs) that the user intends to traverse. Geographic area has been divided into clusters. Different Adjacency Matrices are built for intercluster and the intracluster route to calculate the optimal path using graph theory. In case the desired POIs are not present in the initial calculated optimal route, a fractional distance criteria is proposed. Drivers comfort level and vehicles fuel consumption are considered while designing the proposed algorithm. Various Google Maps Application Programming Interfaces (APIs) are used to give a host of regional POIs that users can select through mobile and on-board navigation system from a web page. Availability of selected POIs can also be displayed to the user by means of data loggers. The developed software is shown to be more intuitive than the present destination finding softwares.

Performance analysis of a Token Bucket Shaper for MPEG4 video and Real Audio signal

The modern communication system has made the world a “Global Village” in true sense. However, as the number of users of this communication system is increasing, the challenges are mounting as well. The users send different types of traffic to the network, however it is necessary that the traffic must conform to the specified network parameters otherwise it will be troublesome. In case the sent traffic violates the agreement between the network and the user, then there is a need to regulate it. Traffic shaping plays an important part in the provision of Quality of Service (QoS) guarantee. Token Bucket Shaper, based on Token Bucket Algorithm is used to shape the bursty and random data in order to provide the QoS guarantee. This paper presents the performance analysis of a Token Bucket Shaper for real world data such as MPEG4 video and Real Audio signal. The effect of varying various Token Bucket Shaper parameters on its performance is also discussed.