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An Introduction of Wireless Sensor Networks (WSN) Technology Zhan Yi (Student ID:80423272) Kuroda Lab. Department of Electrical Engineering Keio University Outline Introduction What is WSN? Why we need it? WSN structure How WSN is organized? What are the specialties of WSN? The achievement some research units have made UCB (David Culler) Intel UCB (Kris Pister ) MIT Media Lab. (Joe Paradiso) Some fields interesting WSN Introduction (What is WSN?) Habitat Monitoring on the Great Duck Island (USA Maine. 2002/2003. UCB & Intel & Atlantic Univ.) (1) (2) (3) (4) (5) Communication Topology Sensor node Multi-hop wireless Internet or Sink / Satellite Base Station area A Cluster-Head or Aggregator Task Manager Node Self-organizing, Density of nodes End User non-homogenous (R) = N R2/A sensor network N is number of nodes in area A R is radio range Introduction (Why we need it?) Seamless and Ubiquitous Communication with the real world. Wide Usages Military applications Environmental applications Health applications Home applications Traffic Surveillance Other commercial applications … Outline Introduction What is WSN? Why we need it? WSN structure How WSN is organized? What are the specialties of WSN? The achievement some research units have made UCB (David Culler) Intel UCB (Kris Pister ) MIT Media Lab. (Joe Paradiso) Some fields interesting WSN Structure (How WSN is organized?) Sensor node (For example, Mote made by UCB) Mote – node used for low-power, wireless, sensor networks’ terminal. Multi-channels transceiver with extended range. Support TinyOS- special operating system developed for WSN. Support for wireless remote reprogramming. sensor boards and data acquisition add- on boards. WSN Structure (How WSN is organized?) Sensor node Sink / Base Station What is behind it? Why it can work? Task management plane Mobility management plane Application Layer Power management plane Multi-hop Transport Layer wireless Network Layer Data-link Layer Physical Layer WSN Structure (How WSN is organized?) Power management plane: Manage a sensor node how to use its energy. know itself Mobility management plane: Detects and registers the movement of sensor nodes, know its neighbors and balance their power and task usage. know others around Task management plane: Balances and schedules the sensing tasks given to a specific region. know whole sensor nodes in the network WSN Structure (How WSN is organized?) Physical Layer: responsible for frequency selection, modulation and data encryption. Data-link Layer: responsible for multiplexing of data streams, data frame detection, Medium Access control (MAC) and error control. Network Layer: route the data supplied by the Transport layer, special multi-hop wireless routing protocols between sensor nodes and sink nodes. Transport Layer: maintain the flow of data if the Application Layer requires it. Needed if End-User accesses the Sensor Network through the Internet. Application Layer: Makes the hardware and software of the lower layers transparent to the End-User. WSN Structure (What are the specialties of WSN?) WSN’s special characters Person unattended, inaccessible. Limited resource - power, memory, MPU… Topology changes/breaks frequently (war field, etc). High density employed, broadcast communication paradigm (normal ad-hoc networks uses point-to-point communications). WSN’s research characteristics Self-organization. Scientific topology, routing and low power.. Fault tolerance & robustness. Security Must be self-organized, self-maintaining and operate at low duty cycle. Outline Introduction What is WSN? Why we need it? WSN structure How WSN is organized? What are the specialties of WSN? The achievement some research units have made. UCB (David Culler) Intel UCB (Kris Pister ) MIT Media Lab. (Joe Paradiso) Some fields interesting Achievement some research units have made Prof. David Culler (UC. Berkeley) Mote (Sensor node) Mote Platform Evolution Achievement some research units have made Tiny OS -- An operating system for tiny devices embedded in physical world a: support self-configure sensor networks. b: small open source, energy efficient, software OS developed by UC Berkeley. c: provides services to simplify writing programs (standard C) that capture and process sensor data and transmit message over the radio. d: open source community: www.tinyos.net. Present work a: efficient routing. b: maintain and update for the Tiny OS (version 2.0 now). c: application based on WSN, like habitat monitoring, structure monitoring, microclimate monitoring… Achievement some research units have made Intel www.intel.com/research/exploratory/heterogeneous.htm Heterogeneous sensor networks: Solve problem of how to improve fault tolerance and energy consumption when the nodes grows and using multi-hoc broadcasting way. a: theory was verified effective. Ad-hoc sensor network with a high bandwidth 802.11 b: lessen data transmission. mesh overlay network based on Intel Xscale Technology c: efficient routing. Intel mote: a: bases on the prototype by Berkeley mote (support TinyOS). b: now is focusing on ultra low power, function level integration, hardware configuration. Path across overlay networks Achievement some research units have made Prof. Kristofer Pister (UC. Berkeley) Smart Dust (sensor node) a: very small size (millimeter-scale, MEMS). b: micromachined CCR, solar cell array, accelerator & photoactive sensor, ADC, microcontroller. c: “Ultra-low energy microcontroller” is reported in ISSCC 2004. Achievement some research units have made Smart Dust is used in company (Dust INC. – Smart Mesh) a: building automation b: industry monitoring c: security and protection services Present work a: Berkeley Webs – use WSN developed technology serve for the school. b: routing security. c: synthetic insect – smart dust with legs. Achievement some research units have made. Prof. Joe Paradiso (MIT. Media Lab) Electronic sensate skin (http://web.media.mit.edu/~lifton/Tribble) a: 33cm diameter sphere with 22 patches which sports vibration-sensitive, local pressure, light, sound, temperature sensors. b: neighbor-to-neighbor wired communication, no centre controller. c: RJ22 cable connects all the patches (15.2kb/s), each patch has microprocessor (8bit/22MIPS). Achievement some research units have made. Wireless wearable system for Gait evaluation (http://www.media.mit.edu/resenv/GaitShoe/index.html) a: an on-shoe device that can be used for continuous and real-time gait monitoring. b: send data wirelessly, providing information about the three- dimensional motion, position, and pressure distribution of the foot. c: real-time data collecting for physical therapy. Some fields interesting Efficient routing Low power Security Programming the Ensemble (configuration) THANK YOU !