International Research Journal of Engineering and Technology (IRJET)
e-ISSN: 2395-0056
Volume: 04 Issue: 07 | July -2017
p-ISSN: 2395-0072
www.irjet.net
Real-Time, Fault Tolerance and Energy-Efficiency (REFER) Enhancement in Wireless Sensor Actuator Networks Shama Ali1, Hanumanthappa S N2 1M.Tech
Student Dept. Of ECE, UBTCE, Davangere, Karnataka, India Professor, Dept. Of ECE, UBTCE, Davangere, Karnataka, India ---------------------------------------------------------------------***--------------------------------------------------------------------2Assistant
Abstract - Wireless sensor and actuator networks
(WSANs) are composed of sensors and actuators to perform distributed sensing and actuating tasks. Most WSAN applications (e.g., fire detection) demand that actuators rapidly respond to observed events. Therefore, real-time (i.e., fast) and fault-tolerant transmission is a critical requirement in WSAN’s to enable sensed data to reach actuators reliably and quickly. Due to limited power resources, energy-efficiency is another crucial requirement. Such requirements become formidably challenging in largescale WSANs. However, existing WSANs fall short in meeting these requirements. To this end, we first theoretically study the Kautz graph for its applicability in WSANs to meet these requirements. We then propose a Kautz-based REal-time, Faulttolerant and EneRgy-efficient WSAN (REFER). REFER embeds Kautz graphs into the physical topology of a WSAN for real-time communication and connects the Kautz graphs using distributed hash table (DHT) for high scalability. We also theoretically study routing paths in the Kautz graph, based on which we develop an efficient fault-tolerant routing protocol. It enables a relay node to quickly and efficiently identify the next shortest path from itself to the destination based only on node IDs upon routing failure, rather than relying on retransmission from the source. Key Words: WSAN, Fault Detection, Fault Diagnosis, Fault Recovery, Network Measurements.
I.
INTRODUCTION
A wireless sensor network (WSN) is a collection of low-cost, low-power and multi-functionality wireless sensing devices that can be densely deployed for surveillance purpose. Traditionally, it is used for data gathering by sampling surroundings and reporting to predefined data sinks. As hardware technology advances, it is now evolving toward service-oriented wireless sensor and actuator networks (WSANs) [1]. A WSAN consists of sensor nodes capable of measuring stimuli in the environment and actuator nodes capable of affecting their local environment. Similar to WSNs, WSAN sensors usually are low-cost and low power devices with a short transmission range that are used for the sensing a physical phenomenon. WSAN actuators are resource-rich devices Š 2017, IRJET
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Impact Factor value: 5.181
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characterized by higher processing and transmission capabilities and a longer battery life. When sensors detect events, they process and transmit the event data to their nearby actuators, which take action on the events. WSANs can potentially be used in applications such as real-time target tracking and surveillance, homeland security, chemical attack detection and environment monitoring in battlefields, factories, buildings and cities. For example, smoke detectors (i.e., sensors) deployed in a building report detected fire events to sprinklers (i.e., actuators); Sensors deployed in a battlefield report their detected malicious objects to actuators, which immediately takes action accordingly. Since sensors are densely deployed to ensure the coverage and topology connectivity usually, the scenario we considered in this paper is a highly dense and mobile WSAN which consists of densely populated and possibly mobile sensors. Actuators need to quickly and reliably respond to nearby sensed events. Delay response may lead to disastrous consequences such as a large loss of life. Therefore, real-time (i.e., very fast) communication is of great importance in guaranteeing the timely actions. Because of node mobility and resultant routing failures, fault-tolerance is crucial to ensure reliable node communication. In addition, energy-efficiency is also a critical requirement for WSANs due to limited resources of sensors. Such requirements become formidably challenging in large-scale WSANs (e.g., battlefield monitoring applications) where the number of sensors is in the order of hundreds or thousands [2]. Most of the routing protocols for mobile ad hoc networks (MANETs) and WSNs treat every node equally and fail to leverage the capabilities of resource-rich devices to reduce the communication burden on lowresource sensors. These protocols are suboptimal for WSANs. Recently, mesh-based [3], [4] and tree-based [5], [6] systems have been proposed for data transmission in WSANs. In the mesh-based methods, physically close sensors form a cluster and the cluster head reports their sensed events to the closest actuator through a multi-hop path. In the tree-based methods, physically close sensors form a tree for data transmission. In both methods, a source node must retransmit a message upon a routing failure. ISO 9001:2008 Certified Journal
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