Teek Parval Sharma

Time synchronization protocol for wireless sensor networks using clustering

In recent years, the use of Wireless Sensor Network (WSN) has been tremendous increased in various fields such as military, environmental, medical, home monitoring and disaster management. In such applications large numbers of nodes are deployed, these nodes work independently and often remain unattended. These nodes sense the data from the environment and communicate the same to the sink or base station. To identifying the correct event time, these nodes need to be synchronized with global clock. Therefore, time synchronization is significant feature in WSNs. Since the performance of time synchronization algorithm is greatly influenced by many factors. The energy conservation is one of the important issues in WSNs which helps to prolong the lifetime of the network. This paper presents a Clustered Time Synchronization algorithm and energy model which conserves the energy beside accuracy while synchronizing the WSNs. The simulation result shows that this algorithm has better synchronization accuracy and low power consumption as compare to RBS and TPSN.

rDFD: reactive distributed fault detection in wireless sensor networks

Generally, fault detection approaches pursue high detection accuracy, but neglect energy consumption due to the high volume of messages exchanged. Therefore, in this work we propose a reactive distributed scheme for detecting faulty nodes. The scheme is able to detect transient and permanent faulty nodes accurately by exchanging fewer messages. In existing fault detection schemes, nodes exchange too many messages after every specific interval to detect suspicious node. However, in the proposed scheme comparatively much less messages are exchanged within a limited geographical area around the suspicious node only and that too when the node suspects its own readings. In the proposed scheme, each node exploits the temporal correlation in its own readings to detect any suspicious behavior. In order to confirm its status, the suspicious node communicates with its immediate neighbors who may be locally good or possible faulty with a certain level of confidence. Thus, the scheme utilizes the strength of both spatial and temporal correlation to find faulty nodes. Also, a confidence level is assigned to each correlated neighbor of suspicious node in order to enhance the detection accuracy. The ns-2 based simulation results show that our scheme performs better by reducing communication overhead and by detecting faulty nodes with high accuracy as compared to existing approaches.

A survey on area coverage in wireless sensor networks

In recent years, Wireless Sensor Networks (WSNs) have gained much attention because of its varying applications from catastrophic region to industrial and household region. In few applications, sensors are deployed in extreme environmental conditions. Hence, node access is not possible in that scenario. Therefore, a large number of sensor nodes are deployed in the target field so that node replacement problem is eliminated. Also, coverage is a very important parameter because it measures how effectively a target field is monitored by the sensor network. This paper focuses on the coverage issue in wireless sensor networks. Initially, three different types of coverage issues are discussed. Then, full coverage issue is examined by considering different points such as node type, deployment type, relation of communication range to sensing range, strategy used to detect full coverage and positioning based/independent algorithms. Some applications of wireless sensor networks are given. Finally, research challenges in the field of area coverage are discussed.

Detecting and reducing the denial of Service attacks in WLANs

Wireless LANs are susceptible to Denial of Service (DoS) attacks. None of the existing wireless security protocols considers protection against them. We propose a novel scheme that detects and reduce DoS attacks in the WLANs. The scheme is based on random number rate control mechanism. It utilizes delegation concept for authentication at the Access Point (AP). Under flooding DoS, AP is unable to verify large number of client authentication requests. It hence, forwards optional message containing hash to the Authentication Server (AS). AS verifies the hash and sends response back to AP, thereby detecting DoS attack. The attack impact at the AP is reduced by dropping the attack packets while selecting the legitimate one. The scheme protects AS from DoS as hash calculations for detection of DoS are done once only. Scheme also prevents against legacy authentication/association and deauthentication/disassociation flooding DoS attacks.

A Key Hiding Communication Scheme for Enhancing the Wireless LAN Security

Authentication per frame and symmetric key based encryption is an implicit necessity for security in Wireless Local Area Networks (LANs). We propose a novel symmetric key based secure WLAN communication scheme. The scheme provides authentication per frame, generates new secret key for encryption of each frame and involves less message exchanges for maintaining the freshness of key and initial vector (IV). It enhances wireless security by utilizing key hiding concept for sharing the symmetric secret key and IV. The shared secret encryption key and IV are protected using counters and then mixed with each other before sending. We prove security of the scheme in Canetti–Krawczyk model.

ZBFR: zone based failure recovery in WSNs by utilizing mobility and coverage overlapping

Wireless sensor networks are more prone to failures as compared to other traditional networks. The frequent faults and failures sometime create large holes causing loss of sensing and connectivity coverage in the network. In present work, a zone based failure detection and recovery scheme is presented to reliably handle such node failures. We first propose a consensus and agreement based approach to elect a suitable monitor node called as zone monitor (ZM). ZM is responsible for coordinating failure recovery activities and maintaining desired coverage within a zone. In order to overcome failure overhead due to false failure detection, a consensus is carried out amongst neighboring nodes of a suspicious node to confirm the correct status with high accuracy. On confirmation of a node failure, the impact of resulting hole on coverage is analyzed and if impact exceeds beyond a particular threshold, a recovery process is initiated. The recovery process utilizes backup nodes having overlapping sensing coverage with failed node and may also relocate some nodes. Firstly a backup node is probed and activated if available. If no backup node is found, the solution strives to recover coverage jointly by recursively relocating some mobile nodes and probing backup nodes. The proposed scheme is analyzed and validated through NS-2 based simulation experiments.

Distributed connectivity restoration in networks of movable sensor nodes

A distributed strategy is proposed for finding relocation overhead associated with movement of each node during cascaded relocation process.A criteria is given for selecting suitable node to relocate during cascaded movement.The performance of the scheme is evaluated and compared with other baseline approaches through example networks.The approach is validated analytically and through ns-2 based simulation. In wireless sensor networks, hostile deployment terrains make resource constrained sensor nodes vulnerable to failures. Sometimes, even a single node failure can partition a network into many disjoint segments and can fail the application mission completely. Since, in most scenarios manual intervention is not possible and hence network must have self-healing capability by detecting and recovering faults at its own. In this paper, a distributed connectivity restoration (DCR) scheme is proposed which on node failure(s) reconstructs the network topology by using cascaded node movements enabling self-healing capability in the network. The DCR is based on partial network information including topological overhead associated with each node. The selection of befitting nodes to be relocated during cascaded movement is done strategically by using partial network information such that the relocation and message overheads are reduced. Ns-2 based simulation experiments are performed to evaluate the performance of the proposed scheme and is compared with other baseline approaches. Display Omitted

Position and hop-count assisted full coverage control in dense sensor networks

In recent years, wireless sensor networks (WSN’s) have gained much attention due to its various applications in military, environmental monitoring, industries and in many others. All these applications require some target field to be monitored by a group of sensor nodes. Hence, coverage becomes an important issue in WSN’s. This paper focuses on full coverage issue of WSN’s. Based on the idea of some existing and derived theorems, Position and Hop-count Assisted (PHA) algorithm is proposed. This algorithm provides full coverage of the target field, maintains network connectivity and tries to minimize the number of working sensor nodes. Algorithm works for communication range less than root three times of sensing range and it can be extended for arbitrary relation between communication range and sensing range. By using hop-count value, three-connectivity in the network is maintained. Also, neighbors information is used to create logical tree structure which can be utilized in routing, redundant data removal and in other areas. Simulation results show that PHA algorithm outperforms layered diffusion-based coverage control algorithm by providing better area coverage and activating fewer nodes.

On the IEEE 802.11i security: a denial-of-service perspective

The IEEE 802.11i standard provides authentication and security at the Medium Access Control layer in wireless local area networks (WLANs). It involves an authentication process followed by a four-way handshake to evolve a key for securing data sessions. The standard suffers under denial-of-service (DoS) attacks. These attacks often block the ongoing communication process and deprive services to the legitimate users. These are easy to conduct while maintaining anonymity of the attackers. It hence becomes imperative to learn about the attacks and their solutions in IEEE 802.11i-protected WLANs so that future research proposals and solutions to mitigate the attack may develop. The paper presents a review of DoS attacks and existing solutions pertaining to the IEEE 802.11i security standard. Copyright

AFDEP: Agreement Based CH Failure Detection and Election Protocol for a WSN

In this paper, we propose an agreement-based fault detection and recovery protocol for cluster head (CH) in wireless sensor networks (WSNs). The aim of protocol is to accurately detect CH failure to avoid unnecessary energy consumption caused by a mistaken detection process. For this, it allows each cluster member to detect its CH failure independently. Cluster members employ distributed agreement protocol to reach an agreement on failure of the CH among multiple cluster members. The detection process runs concurrently with normal network operation by periodically performing a distributed detection process at each cluster member. To reduce energy consumption, it makes use of heartbeat messages sent periodically by a CH for fault detection. Our algorithm would provide high detection accuracy because of agreement protocol.