On Achieving Maximum Network Lifetime Through Optimal Placement of Cluster-heads in Wireless Sensor Networks High-Speed Networking Lab. Dept. of CSIE, Fu-Jen Catholic University Adviser: Jonathan C. Lu, Ph.D. Speaker: Yen-Fong Wang
Outline Abstract Introduction Related work Optimal placement of cluster-heads (OPC) algorithm Simulation results Conclusion Reference
I. Abstract In wireless sensor network, the network lifetime is an important issue when the size of the network is large The cluster-heads near the sink get overloaded and drained out sooner Formulate an optimization problem and find the optimum number of cluster-heads to be deployed and their optimum transmission ranges
Outline Abstract Introduction Related work Optimal placement of cluster-heads (OPC) algorithm Simulation results Conclusion Reference
II. Introduction There are two basic network architectures in WSN Multi-hop Cluster-heads Multi-hop: The sensor nodes are homogeneous and they transmit data packets via intermediate sensor nodes in a multi-hop fashion to the sink Cluster heads: The whole area is divided into a number of cluster regions Cluster-heads reduce the number of transmissions by aggregating the sensed information thereby minimizing the energy dissipation in the network
Outline Abstract Introduction Related work Optimal placement of cluster-heads (OPC) algorithm Simulation results Conclusion Reference
III. Related work The lifetime of the sensor nodes is balanced by varying the radio’s transmission range Sensor nodes reach the cluster-head station using Single-hop mode Multi-hop mode Hybrid communication mode The cluster-heads Gather the sensed information from sensor nodes Perform the required computation Have long transmission range than that of the sensor nodes
Outline Abstract Introduction Related work Optimal placement of cluster-heads (OPC) algorithm Simulation results Conclusion Reference
IV. OPC Algorithm Places additional cluster-heads near the sink to handle the high load Provides the optimum density and radio transmission range for the cluster-heads in order to achieve the maximum network lifetime with the minimum network cost Network model The network is divided into number of clusters Cluster-heads transmit packets to the data sink in a multi-hop path via other cluster-heads Sensor nodes communicate with their cluster-heads either in a single or multi-hop path
IV. Cluster architecture in wireless sensor network
IV. OPC Algorithm Relationship between node density and transmission range Optimum number of cluster-heads problem is non linear integer programming problem (NLP)
IV. OPC Algorithm Varying dense placement algorithm The cluster-heads near the sink will run out of power sooner and reduce the network lifetime Minimum number of cluster-heads required : the minimum number of cluster-heads required r : the transmission range for cluster-heads
IV. Varying dense placement of cluster-heads 1 2 3 4 5 6
IV. OPC Algorithm Cluster-heads can reduce the transmission range, in order to save energy
IV. OPC Algorithm The hop distance between the sink and the border cluster- heads is N, where The objective is to minimize the network cost is K: the number of packets transmitted by a cluster-heads after collecting the data from sensor nodes
Outline Abstract Introduction Related work Optimal placement of cluster-heads (OPC) algorithm Simulation results Conclusion Reference
V. Simulation results Use GloMoSim simulator to simulate the results Compared uniform dense placement (UDP), varying dense placement (VDP) and OPC algorithms in the network lifetime, collisions and latency Simulation parameters Network size (Terrain radius): 1000 – 2000 meters Bandwidth: 48 kbps Packet size 512 bytes Transmission range (UDP/VDP): 200 meters Transmission range (OPC): 80-200 meters MAC protocol: IEEE 8.2.11 DCF
V. Network lifetime for different network sizes
V. Effect of varying traffic on collisions
V. Effect of varying traffic on latency
Outline Abstract Introduction Related work Optimal placement of cluster-heads (OPC) algorithm Simulation results Conclusion Reference
VI. Conclusion The optimum number if cluster-heads required and their respective transmission ranges This paper’s algorithm achieves the maximum network lifetime with the minimum network cost and less number of collisions
Outline Abstract Introduction Related work Optimal placement of cluster-heads (OPC) algorithm Simulation results Conclusion Reference
VII. Reference On Achieving Maximum Network Lifetime Through Optimal Placement of Cluster-heads in Wireless Sensor Networks Dhanaraj, M.; Siva Ram Murthy, C.; IEEE International Conference on Communications, 2007. ICC `07. 24-28 June 2007