Multirate adaptive awake-sleep cycle in hierarchical heterogeneous sensor network BY HELAL CHOWDHURY presented by : Helal Chowdhury Telecommunication laboratory, university of Oulu

contents Introduction Hierarchical Heterogeneous network Multirate Adaptive multirate Scheduling Future Work and conclusion Reference

Introduction (1/3) Sensor network –low power, low cost, small size communication node which send sensed data to the receiver. –Self organised –Deployment random deterministic –Application Battle field Habitat monitoring Health monitoring Power Consumption –In WSN, energy is consumed by sensing, processing and in communication –less power sensing procesing –major power communication –power amplifier –other electronics

Introduction (2/3) Topology –Flat Nodes communicate with the sink via possibly multi-hop routes by using peer nodes as relays. –Hierarchical cluster are formed so that sources within a cluster send their data (via a single hop or multi-hop depending on the size of the cluster. Communication method – Single-Hop The simplest is direct transmission, where each sensor directly sends gathered information to the remote receiver independent of each other. –Multi-Hop no direct transmission from source to final destination. uses multi-hop routing. – Clustering Cluster head can be selected dynamically or pre-assigned depending on the application. clustering is arguably one of the most frequently proposed and used methods to organize communications in large scale network.

Introduction (3/3) Transmission Rate –Single Rate All sensor nodes use fixed transmission rate. –Multi Rate Sensor nodes uses multi transmission rate Higher rate Middle rate Lower rate –bit rate varies according to the constraints correlation channel conditions etc MAC –Non contention Fixed assigned channel for each sensor node using different multiple access techniques. –TDMA. –Contention –Not fixed assigned channel, nodes are competing to get access the channel Coordinate –RTS/CTS Non coordinate –less control overhead

Hierarchical Heterogeneous network (1/1) Hierarchical Heterogeneous has two types sensors –Normal node low power mainly for sensing data and limited range of communication capabilities. –Relay node High power Data is processed, compressed, aggregated and relayed Communication –Single Hop many-to-one –Multi-Hop Four group of sensors have been formed according to tthe relative power from the relay node.

Multirate (1/1) Correlation based multi-rate adaption –All sensor nodes transmit to relay node –Higher correlation lower transmission rate –Correlation(higher  middle  lower  )transmission rate(1 .5 .7)

Adaptive multirate Scheduling (1/3) The reservation access control protocol is an implementation of the RTS/CTS collision avoidance protocol and is part of the Distributed Coordination Function (DCF) in the IEEE MAC. Modified RTS and CTS control frames –rate subfield uses for rate information. –length subfield gives the size of the data packet in octets.

Adaptive multirate Scheduling(2/3) per iod AwakeSleepActions:communication data aggregation T1Everybod y No oneControl informaion Queries from relay node to sensor nodes T2G2,G4G1,G3,RG2 and G4 T3G1,G3G2,G4,RG1 and G3 T4G1,G2G3,G4,RG1 and G2 T5G1,RG2,G3,G4G1 and R R nodes performs data aggregation T6RG1,G2,G3, G4 R and relay nodes R nodes performs data aggregation T7No oneEverybodyNone, Every node is asleep

Adaptive multirate Scheduling (3/3) Imact of multi rate in hirarchical heterogeneous network increase the sleep time. The more lower the bit rate the more sleep time which ultimately reduces energy consumption in the normal sensor node as well as relay node data preventation algorithm can be employed either in normal sensor node or in relay node for deep sleep.

Future Work and conclusion We have proposed multi rate strategies to examine power efficient adaptive awake-sleep cycle in hierarchical heterogeneous network. Correlation based adaptive scheduling has been demonstrated to reduce energy consumption. We are looking at the impact of adaptive awake- sleep cycle on the mixed rate system.

Reference [1] Carlos Pomalaza-Raez, “Hierarchical Heterogeneous Architectures for Wireless Sensor Networks,” Center for Wireless Communications, University of Oulu, Finland. [2] W.Heinzelman, A. Chandraksan, and H.Balakrishnan, “Energy-Efficient Communications Protocols for Wireless Microsensor Networks,” Proceedings of the 33rd International Conference on System Sciences, January [3] E.J.Duarte-Melo and M.Liu, “Analysis of Energy Consumption and Lifetime of Heterogeneous Wireless Sensor Networks,” Proc. IEEE Globecom, November 2002, Taipei, Taiwan. [4] A. Depedri, A. Zanella, R. Verdone, "An Energy Efficient Protocol for Wireless Sensor Networks," Autonomous Intelligent Networks and Systems (AINS 2003), Menlo Park, CA, June 30-July 1, 2003, pp [5] W. Rabiner Heinzelman, A. Chandrakasan, and H. Balakrishnan, “Energy-Efficient Communication Protocol for Wireless Microsensor Networks,” Proceedings of the 33rd International Conference on System Sciences (HICSS '00), January 2000, pp [6] F. Akyildiz, W. Su, Y. Sankarasubramaniam, and E. Cayirci, “A Survey on Sensor Networks,” Computer Networks, 2002, pp [7] G. Holland, N. Vaidja, P.Bahl, “A Rate-Adaptive MAC Protocol for Wireless Networks,” ACM/IEEE Int. Conf. on Mobile Computing and Networking (MOBICOM'01), Rome, Italy, July 2001.A Rate-Adaptive MAC Protocol for Wireless Networks

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