Sachin Gajjar

Work place: Institute of Technology, Nirma University, Ahmedabad-382481, India



Research Interests: Computer systems and computational processes, Computer Architecture and Organization, Computer Networks


Sachin Gajjar received his B.E. degree in Electronics and Communication Engineering from Government Engineering College, Gujarat, India in 1999. He received his M.Tech. degree in Computer Technology from Indian Institute of Technology, Delhi (IIT Delhi) in 2007. He worked at Videocon International Limited, Gandhinagar, Gujarat, India in Product Development Group from June 1999 to December 1999. From January 2000 to December 2000 he worked with Cincinnati Milacron, Ahmedabad, Gujarat, India in Software Development Group. In January 2001, he joined L. D. College of Engineering, Ahmedabad, Gujarat, India as Lecturer in Computer Science and Engineering Department and worked there till August 2002. Since August 2002, he is working as Assistant Professor in Electronics and Communication Engineering Department, Institute of Technology, Nirma University, Ahmedabad, Gujarat, India. Currently he is doing his Ph.D. in the area of wireless sensor networks in Computer Science and Engineering Department, Institute of Technology, Nirma University. His research interests include computer networks and wireless sensor networks.

Author Articles
LEFT: A Latency and Energy Efficient Flexible TDMA Protocol for Wireless Sensor Networks

By Sachin Gajjar Nilav Choksi Mohanchur Sarkar Kankar Dasgupta

DOI:, Pub. Date: 8 Jan. 2015

This paper proposes latency and energy efficient flexible TDMA (LEFT), a medium access control (MAC) combined with routing protocol for data gathering from number of source nodes to a master station (MS) in a wireless sensor network (WSN). TDMA provides fairness, collision-free communication and reduces idle listening, which saves network energy. Data latency is reduced by allocating same transmission slots to nodes falling out of interference range of each other. Unlike a conventional TDMA, LEFT provides flexibility through slot seizing, wherein a non-holder of a slot can use slot when holder does not have data to send. This increases channel utilization and adaption to dynamic traffic patterns of WSN applications. Further, a node on a multi-hop path towards MS decides to participate in routing based on (i) its location with respect to MS, to forward data in correct direction, (ii) its current status of residual energy, to uniformly distribute energy across network, (iii) its transit traffic load, to prevent local congestion, (iv) its communication link quality, to guarantee reliable data delivery. This decision requires simple comparisons against thresholds, and thus is very simple to implement on energy, storage and computationally constrained nodes. LEFT also encompasses techniques to cater to link and node breakdowns. Experimental analysis of LEFT; Advertisement-based TDMA; Data gathering MAC; Energy Efficient Fast Forwarding and Cross layer MAC protocols using TI’s EZ430-RF2500T nodes shows that LEFT is 65% more energy efficient compared to Cross layer MAC. Data latency of LEFT is 27 % less, delivery ratio is 17 % more and goodput is 11 % more compared to Cross layer MAC.

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