Shirshu Varma

Distance measurement and error estimation scheme for RSSI based localization in Wireless Sensor Networks

With the advent of Wireless Sensor Networks (WSNs) covering a whole gamut of applications which is getting broader by the day and it is indeed necessary to study the nuances in WSN out of which aforementioned is one. WSNs consists of large number of deployed sensor nodes and a base node for aggregating data from deployed sensor nodes. Wireless Sensor Networks (WSN) are attribute based and they are not concerned about the location of deployed sensor node from which the base node is receiving the data. In certain specific applications like health monitoring systems, tracking systems and dynamic networks, the location of transmitting node is essential. Location of the deployed sensor nodes can be found either by TOA, TDOA or Received Signal Strength (RSS) measurements. In this paper we tried to estimate the approximated distances of deployed sensor nodes using RSS measurements. The estimated distances can be further used for locating the position of deployed sensor nodes. The working model has been realised in TinyOs and RSS measurements are made using Telosb nodes.

Geographic Node-Disjoint Path Routing for Wireless Sensor Networks

One of the challenging issue in wireless sensor networks (WSNs) is efficiently route the multimedia information. In this letter, we propose an efficient geographic routing algorithm for multimedia data transmission such as audio, video, etc., in WSNs. It finds one near to shortest path per iteration and can be performed repeatedly iteration to find more on-demand shortest node-disjoint routing paths. This algorithm achieves high-throughput with low delay that is required for multimedia data transmission over WSNs.

Base station initiated dynamic routing protocol for Heterogeneous Wireless Sensor Network using clustering

Wireless sensor networks have received excessive attention in now a days. Research in all field in wireless sensor network (WSN) till now has assumed that sensors in network is homogeneous, means that all the nodes are same, especially for routing protocols that has used clustering like LEACH, LEACHC, and PEGASIS etc. But in the clustering algorithm where some nodes have to work as cluster heads, if they are same as the other nodes, this would lead the lifetime constraint in WSN. Because of this most we shall be considering here the heterogeneous WSN, where the nodes which will work as cluster head will contain more energy, computational and communication power than normal nodes. In this paper we introduce a routing protocol that is based on clustering and uses heterogeneity in nodes to increase the network lifetime.

A Range Based Localization System in Multihop Wireless Sensor Networks: A Distributed Cooperative Approach

In recent times although there is lot of research in field of localization application but very few aims at localization module with optimal energy consumption. Localization, being inevitable for a range of applications, is also a basis for many network operations such as data packet forwarding i.e. routing and sensing coverage in wireless sensor networks. With a range of application scenario, it is a challenging task to design a localization module for a wireless sensor network consisting of sensor nodes with limited capacity in terms of power, processing and storage etc. This paper presents a simple model of a range based localization system that employs distributed computing in a collaborative and cooperative manner. The aim of this work is to modify a range based localization algorithm to utilize scarce resources optimally along with improved performance by changing the inherent methodologies of position estimation. In this research work basically the role of a media access control scheme (MAC) in the localization module is investigated. A MAC is basically used to save the energy by reducing collisions and retransmission of range packets. Further, energy is conserved by restricting the coverage to a smaller part containing the neighbours up to certain hops and that is formed by dividing the whole network area into clusters. To analyse the performance spectrum, we have simulated the localization method under a variety of application scenarios and lead to the conclusion that this approach increases the efficiency of localization in wireless sensor networks. In the simulation process, every minute aspect of sensor network localization model including the topology, range, mobility, channel, propagation schemes etc. were considered and the performance was finally analyzed.

Cluster based hierarchical wireless sensor networks (CHWSN) and time synchronization in CHWSN

A cluster based hierarchical wireless sensor network architecture is proposed to facilitate more than one application sharing the whole or a part of a wireless sensor network, where each application may have its own network, processing requirements and protocols. Such a network is divided into clusters and the clusters are organized hierarchically. For synchronizing the CHWSN there is the requirement for a cluster based hierarchical time synchronization algorithm. None of the already existing time synchronization algorithms satisfy the needs of time synchronization in our CHWSN architecture. Thus the existing time synchronization algorithms TPSN (time synchronization protocol for sensor networks) and FTSP (Flooding Time Synchronization Protocol) are modified to fulfill the needs of time synchronization in CHWSN architecture and developed the cluster based hierarchical, flooding time synchronization algorithm (CBH-FTS). It is a hybrid algorithm, where instead of flooding the synchronization messages to neighbors node, the root node multicasts the time-sync message to selected cluster-heads using the relevant semantics. Hierarchy of cluster-heads could transmit the synchronization messages down the hierarchy of cluster-heads thus synchronizing only the required part of the network associated with an application. The synchronization could be a result of a decision at root node or could be a result of a request for synchronization from a node to a cluster-head.The CBH-FTS Protocol is semantic driven and covers multiple levels in hierarchy.

Performance Analysis of Optimized Medium Access Control for Wireless Sensor Network

In this work, we carried out the performance analysis of Optimized Medium Access Control (MAC) Protocol for the wireless sensor network. This MAC protocol solves the energy inefficiency taking nodes latency into consideration based on the network traffic. It achieves high-energy efficiency under wide range of traffic loads and is able to adjust itself to improve the delay performance when the network traffic load is high.

Challenges and Implementation on Cross Layer Design for Wireless Sensor Networks

AbstractCross-layer design (CLD) has emerged as an important area in wireless sensor networks (WSNs). Cross-layer enables interaction between different non- adjacent layers and, thereby, exchanging information between layers, which, indeed is not possible in traditional architectures. CLD is used for enhancing the performance of the existing architectures by utilizing the flexible prospects of the protocol layers to improve system performance and to satisfy QoS demands of the applications. The CLD leads to increase in network efficiency and optimized network throughput. In this paper, the various cross-layer design methodologies for WSNs have been reviewed, which have basically been designed to enhance the network performance in WSN. At the end, the paper proposes a CLD based on ongoing research.

Energy Efficient Data Aggregation in Mobile Agent Based Wireless Sensor Network

Energy efficiency have always been a priority while designing wireless sensor networks. Introduction of mobile agent technology in wireless sensor networks for collaborative signal and information processing has provided the new scope for efficient processing and aggregation of data. Mobile agent based distributed computing paradigm offers numerous benefits over the existing and commonly used client/server computing paradigm in wireless sensor networks. Mobile agent performs the task of data processing and data aggregation at the node level rather than at the sink, thus, eliminating the redundant network overhead. One of the most important issues in mobile agent based paradigm is planning of an itinerary for agent traversal. In this paper, we have proposed a dynamic mobile agent based data aggregation approach that takes into consideration energy efficiency, network lifetime, end to end delay and aggregation ration while making the decision for migration of agent in multihop sensor network. As our approach focuses on finding the most informative route by traversing comparatively less number of nodes consequently mobile agent takes less time to return to processing element, thus, exhibiting lower delay.

Data Aggregation in Cluster based Wireless Sensor Networks

A wireless sensor network is a wireless network, in which we basically use tiny devices which monitor physical or environmental conditions at different regions. Thus the wireless sensor network basically comprises of sensing, communicating, computing, programming and control ingredients. We can design and configure sensor network applications designed that have better fault tolerance. In most applications sensor networks are deployed once and operate for a long period of time. In this respect managing and maintaining wireless sensor network becomes an important task. However, the problem of limited energy constraint presents a major challenge for the network deployment. Hence it clearly follows that in order to gather information from node to node we require data forwarding protocol. So the aim of any data forwarding protocol is to conserve energy to maximize the network lifetime. Sensor nodes are capable of performing in-network aggregation of data coming from more than one source. In this paper we have concentrated on energy consumption issue and designed energy efficient data aggregation protocol named EBINA. Thus protocol using a cluster-based wireless sensor network is more relevant. Each cluster is executed independently and thus we obtain an energy efficiently data, which finally is aggregated in a cluster by this the lifetime of the cluster is also increased. We have used Network Simulator 2(NS-2) for simulating the protocol.

Statistical Energy Efficient Multipath Routing Protocol

The main purpose of a sensor network is to gather information about the environment or object they are sensing and deliver it to the end user. Therefore, the quantity and quality of the data delivered to the end-user is very important. The immense potential of wireless sensor networks (WSNs) has created a growing awareness of the need for reliability in such networks. Another major concern in the design of WSN protocols is energy efficiency. Reliability and energy efficiency are not independent of each other as reliability may be achieved by retransmitting packets. Thus there exists a trade off between reliability and energy efficiency; reliability may be increased at the cost of higher energy consumption. Thus conventional protocols face a threshold beyond which life time of network cannot be increased for a given required reliability. But all packets in a network need not require the same level of reliability. In this paper we argue that the overall life time of the network can be increased by making a more uniform resource utilization which in turn can be achieved by shaping the traffic flow. We introduce SEEMPr (statistical energy efficient multipath routing) which is a statistical approach that attempts to evenly distribute the energy consumption over a large part of network while maintaining the reliability of the network by choosing a route based on urgency of the message. At the end we compare SEEMPr with conventional routing protocol and show that SEEMPr provides a high variation in number of nodes participating in routing of packet thus providing a method to vary the energy consumption and reliability of the network.