IJESRT Vol 3 5 May 2014

International Journal of Engineering Sciences & Research Technology, 2014

A typical WSN is composed of a large number of computing devices known as nodes embodying limited set of resources. These nodes are interfaced with sensors whose job is to sense and monitor the surrounding environment for various purposes and disseminate sensed data to some special computing devices called destination or base-stations in a coordinated manner where the destination nodes further process and analyze the reported data to draw conclusions about the reported activity. Since the sensors in Wireless sensor networks (WSNs) operate independently, their local clocks may not be synchronized with one another. This can cause difficulties when trying to integrate and interpret information sensed at different nodes. Time synchronization of WSNs is crucial to maintain data consistency, coordination, and perform other fundamental operations. Synchronization is considered a critical problem for wireless adhoc networks due to its de-centralized nature and the timing uncertainties introduced by the imperfections in hardware oscillators and message delays in both physical and medium access control (MAC) layers. All these uncertainties cause the local clocks of different nodes to drift away from each other over the course of a time interval. Therefore, Time synchronization is considered as an important research issue in wireless sensor networks (WSNs). Many applications based on these WSNs assume local clocks at each sensor node that need to be synchronized to a common notion of time. Features and concept of a lightweight tree structured referencing time synchronization (TSRT) approach to achieve a long-term network-wide synchronization with minimum message exchanges and exhibits a number of attractive features such as highly scalable and lightweight is presented in this paper. We have also shown evaluation, analysis and comparison study of TSRT with existing synchronization protocols.

A typical WSN is composed of a large number of computing devices known as nodes embodying limited set of resources. These nodes are interfaced with sensors whose job is to sense and monitor the surrounding environment for various purposes and disseminate sensed data to some special computing devices called destination or base-stations in a coordinated manner where the destination nodes further process and analyze the reported data to draw conclusions about the reported activity. Since the sensors in Wireless sensor networks (WSNs) operate independently, their local clocks may not be synchronized with one another. This can cause difficulties when trying to integrate and interpret information sensed at different nodes. Time synchronization of WSNs is crucial to maintain data consistency, coordination, and perform other fundamental operations. Synchronization is considered a critical problem for wireless adhoc networks due to its decentralized nature and the timing uncertainties introduced by the imperfections in hardware oscillators and message delays in both physical and medium access control (MAC) layers. All these uncertainties cause the local clocks of different nodes to drift away from each other over the course of a time interval. Therefore, Time synchronization is considered as an important research issue in wireless sensor networks (WSNs). Many applications based on these WSNs assume local clocks at each sensor node that need to be synchronized to a common notion of time. Features and concept of a lightweight tree structured referencing time synchronization (TSRT) approach to achieve a long-term network-wide synchronization with minimum message exchanges and exhibits a number of attractive features such as highly scalable and lightweight is presented in this paper. We have also shown evaluation, analysis and comparison study of TSRT with existing synchronization protocols.

2014

Time synchronization for wireless sensor networks (WSNs) has been studied in recent years as a fundamental and significant research issue. Time synchronization in a WSN is a critical for accurate time stamping of events and fine-tuned coordination among the sensor nodes to reduce power consumption. Time synchronization in WSNs is crucial to maintain data consistency, coordination, and perform other fundamental operations. Synchronization is considered a critical problem for wireless adhoc networks due to its de-centralized nature and the timing uncertainties introduced by the imperfections in hardware oscillators and message delays in both physical and medium access control (MAC) layers. All these uncertainties cause the local clocks of different nodes to drift away from each other over the course of a time interval. Therefore, Time synchronization is considered as an important research issue in wireless sensor networks (WSNs). Many applications based on these WSNs assume local clocks at each sensor node that need to be synchronized to a common notion of time. Features and concept of improved version of tree structured referencing time synchronization (TSRT) approach to achieve a longterm network-wide synchronization with minimum message exchanges and exhibits a number of attractive features such as highly scalable and lightweight is presented in this paper. The evaluation and analysis study of Multi-hop TSRT scheme is shown based on results obtained from logical model of the network. We have also shown comparison study of TSRT with existing synchronization protocols.

Time synchronization for wireless sensor networks (WSNs) has been studied in recent years as a fundamental and significant research issue. Many applications based on these WSNs assume local clocks at each sensor node that need to be synchronized to a common notion of time. Time synchronization in a WSN is critical for accurate time stamping of events and fine-tuned coordination among the sensor nodes to reduce power consumption. This paper proposes a bidirectional, reference based, tree structured time synchronization service for WSNs along with network evaluation phase. This offers a push mechanism for (i) accurate and (ii) low overhead for global time synchronization. Analysis study of proposed approach shows that it is lightweight as the number of required broadcasting messages is constant in one broadcasting domain.

2003

Wireless ad-hoc sensor networks have emerged as an interesting and important research area in the last few years. The applications envisioned for such networks require collaborative execution of a distributed task amongst a large set of sensor nodes. This is realized by exchanging messages that are timestamped using the local clocks on the nodes. Therefore, time synchronization becomes an indispensable piece of infrastructure in such systems. For years, protocols such as NTP have kept the clocks of networked systems in perfect synchrony. However, this new class of networks has a large density of nodes and very limited energy resource at every node; this leads to scalability requirements while limiting the resources that can be used to achieve them. A new approach to time synchronization is needed for sensor networks.