Network and Systems Laboratory nslab.ee.ntu.edu.tw Copyright © Wireless Sensor Networks: Overview & Application Polly Huang Department of Electrical Engineering National Taiwan University

Network and Systems Laboratory nslab.ee.ntu.edu.tw Road Map Overview What is a sensor network? Applications How can the sensor network be useful? Copyright © 2008

Network and Systems Laboratory nslab.ee.ntu.edu.tw Sensor Network Copyright © 2008

Network and Systems Laboratory nslab.ee.ntu.edu.tw Sensors? Also the biomedical sensors: EMG, EKG, pulses, emotions, etc camera mic accelerometer gyro pressure thermal GPS Copyright © 2008

Network and Systems Laboratory nslab.ee.ntu.edu.tw Sensor Nodes Today MICA, cm X 3.18cm 4 MHz CPU 128K ROM 512K RAM 40kbps Radio range x00 feet Sensors, battery not included Spec, March mm X 2.5mm CPU, memory, RF transceiver Sensors, battery, antenna not included < 1 dollar if mass-produced Copyright © 2008

Network and Systems Laboratory nslab.ee.ntu.edu.tw Embedded Sensor Node Intel® Xscale CPU Analog and digital radio Flash and SRAM memory Sensors Copyright © 2008

Network and Systems Laboratory nslab.ee.ntu.edu.tw Embedded Sensor Network Copyright © 2008

Network and Systems Laboratory nslab.ee.ntu.edu.tw Applications Home, Office, Healthcare, Science & Nature, Agriculture Copyright © 2008

Network and Systems Laboratory nslab.ee.ntu.edu.tw Intel Digital Home Copyright © 2008

Network and Systems Laboratory nslab.ee.ntu.edu.tw UCSB Bren School of Environmental Science and Management Day-lighting controls Operable windows control taking advantage of on- site ocean breezes Airflow controls based on CO 2 level Copyright © 2008

Network and Systems Laboratory nslab.ee.ntu.edu.tw Long-Term Nursing Home Accelerometers Pressure sensor Muscle activity Camera Orientation sensor Fall detection Vital sign monitoring Dietary/exercise monitoring

Network and Systems Laboratory nslab.ee.ntu.edu.tw The Channel Islands Fox Copyright © 2008

Network and Systems Laboratory nslab.ee.ntu.edu.tw Fancy Californian Winemaking Temperature Soil moisture Pest/disease Copyright © 2008

Network and Systems Laboratory nslab.ee.ntu.edu.tw Taiwan Value! Home: Security (Crime Rate) Industry: IC (Energy crises) Healthcare: Elder Care ( 健保 Burden) Agriculture: Orchid Growing (Big Export Business) Copyright © 2008

Network and Systems Laboratory nslab.ee.ntu.edu.tw Our Applications Maria (chronic disease) BL-Live (smart building) Ubiquitous Care (patient safety) Copyright © 2008

Network and Systems Laboratory nslab.ee.ntu.edu.tw MicaZ Sensor Node Xscale-based Embedded System Maria: The Elder ’ s Companion WiFi GPRS Sensor Network Full-Fledged Server

Network and Systems Laboratory nslab.ee.ntu.edu.tw BL-Live: Elevator Report Sensor Network Copyright © 2008

Network and Systems Laboratory nslab.ee.ntu.edu.tw U-Care: Localization Copyright © 2008

Network and Systems Laboratory nslab.ee.ntu.edu.tw Sensor Network Problems 1. Network and Communication 2. Information or Signal Processing Copyright © 2008

Network and Systems Laboratory nslab.ee.ntu.edu.tw Wireless Technologies Mote PicoNet IEEE bluetoothWLAN Rangex m 10 m100 m Max BW40 kbps224 kbps723 kbps11Mbps Band310, 433, 868/916M Hz MHz, 2.4GHz 2.4GHz Power (data mode) (1mA)(10mA)30mA250mA Copyright © 2008

Network and Systems Laboratory nslab.ee.ntu.edu.tw Indoor Wireless Transmission Source

Network and Systems Laboratory nslab.ee.ntu.edu.tw Packet Reception Rate Good linkGrey linkBad link Copyright © 2008

Network and Systems Laboratory nslab.ee.ntu.edu.tw Problems in Networking No one node can reach every other node Need multiple routing Each node can reach a high number of other nodes Need MAC with collision avoidance No link is 100% reliable Need (quasi-)reliable data transport Copyright ©

Network and Systems Laboratory nslab.ee.ntu.edu.tw (Used to be) Hot Topics MAC Energy efficient MAC Data Dissemination Data-centric routing Energy efficient routing Hop-by-hope retransmission Copyright ©

Network and Systems Laboratory nslab.ee.ntu.edu.tw Sensor Signals - Accelerometer Copyright © MariaBL-Live Identify period of time where there is no activity Identify the direction/duration of the elevator moving

Network and Systems Laboratory nslab.ee.ntu.edu.tw Problem in Signal Processing Information to derive Very application dependent Signals come with noise Need filters Computation Cost Compute on board or else Copyright ©

Network and Systems Laboratory nslab.ee.ntu.edu.tw (Used to be) Hot Topics In-network processing Do signal processing on board or with the help of other nodes Collaborative signal processing Derive information with the help of sensor data from multiple nodes Ranging-based localization Localize mobile nodes by triangulation Copyright ©

Network and Systems Laboratory nslab.ee.ntu.edu.tw Road Map Zigbee Stack Designed for indoor home appliances AODV, CSMA-like MAC Classic Protocols Designed for outdoor sensor networks Directed diffusion, S-MAC In-Trend Protocols Designed for better QoS Magnetic diffusion, newer MAC Copyright ©

Network and Systems Laboratory nslab.ee.ntu.edu.tw Copyright © Questions?