Wireless Sensor Network Prabhakar Dhekne Bhabha Atomic Research Centre

1. Wireless Sensor Network Prabhakar Dhekne Bhabha Atomic Research Centre Talk at SASTRA

2. Why Talk About Wireless? • Wireless communication is not a new technology but cell phones have brought revolution in wireless communication • Wireless Technology has changed the way • Organizations & individuals work & live today • In less than 10 years • World has moved from fixed to wireless networks • Allowing people, mobile devices & computers talk to each other, connect without a cable • Only available option for field data acquisition • Interconnectivity with multiple devices • Using radio-waves, sometimes light • Frees user from many constrains of traditional computer & phone system Talk at SASTRA

3. Future State of Computing Technology? Mobile, many computers Small Processors Low Power Consumption Relatively Low Cost Ubiquitous Computing Talk at SASTRA

4. Ubiquitous Computing • Small, mobile, inexpensive computers…..everywhere! • Fade into the background of everyday life • Computers everywhere provides potential for data collection….sensors! • Temperature • Light • Sound • Motion • Pressure • Many others!!! Talk at SASTRA

5. Growth in Wireless Systems • Rapid growth in cellular voice services • Cell phones everywhere! • Several wireless technology options have been available for the last ~10-20 yrs • mini cell stations using existing standards like CDMA or GSM • wireless PABX using PCS standards such as DECT or PHS/PACS • satellite and microwave backhaul • Above solutions OK for voice & low-speed data, but do not meet emerging needs for broadband access and mobile data Talk at SASTRA

6. Mobile Healthcare Technologies Mobile Healthcare can be regarded as the integration of technologies of medical sensors, mobile computing, and wireless communications into a system of medical assistance. Talk at SASTRA

7. Application Examples • Monitoring of patient’s vital signs • Diabetes • Asthma • Hypertension • ECG • Predictive usage in order to minimize the needs for medication • Improving the quality of life Talk at SASTRA

8. Potential Benefits • Increasing the physician productivity and efficiency. • Wireless sensors enable the patients’ freedom of movements and therefore promote new ways of monitoring the patient. • Providing clinicians remote access to patient’s information eliminates the need to manually locate and search through patient’s data. • Enabling telemonitoring in emergency scenarios and making remote diagnosis possible. Talk at SASTRA

9. Mobile Healthcare The provision of Real Time patient care. • No matter where the clinician is • No matter where the patient is • To apply physiological and medical knowledge, advanced diagnostics, simulations, and effector systems integrated with information and telecommunications for the purposes of enhancing operational and medical decision-making, improving medical training, and delivering medical treatment across all barriers Talk at SASTRA

10. Typical Demo System • The patient is provided with a wearable wireless sensor. The signal from the sensor is captured in a Node situated in a mobile phone. • The system allows ubiquitous access to patient’s data and medical information in real-time via the mobile phone. • The medical data is stored & processed in a server, and can be used for establishing diagnostics and treatments. Talk at SASTRA

11. Application server • Application server centralises the received data and presents it to the user as: • Raw data • Formatted as graphs App Server DB Talk at SASTRA

12. Wireless Technology • Emerging mainstream wireless technologies provide powerful building blocks for next-generation applications • WLAN (IEEE 802.11 “WiFi”) hot-spots for broadband access, Bluetooth • PDAs and laptops with integrated WLANs • Broadband Wireless access technology- MAN (Alternative to DSL) • IEEE 802.16 10-30 Km 40 Mbps WiMax • Wide area wireless data also growing • SMS, GPRS, Edge, CDMA2000 1xEV-DO (2.4 Mbps data optimized) • Variety of interesting devices (e.g. Treo, Sidekick) • Networking of embedded devices • Smart spaces, sensor networks (IEEE 802.15.4a- ZigBee) • Context-aware mobile data services and web caching for information services • Wireless sensor nets for monitoring and control • VOIP for integrated voice services over wireless data networks Talk at SASTRA

13. IrDA: P2P wireless • Infra-red Data Association • Based on Half Duplex Point-to-Point concept • Frequency below the red end of spectrum making it invisible • Eliminate the need for cables • Clear line-of-sight • Short-range (few meters) • Simplest, most prevailing wireless standard • No fixed speed 9.6 Kbps, 4Mbps • Discovery Mode to find out data rate, size • Token based transmission • IrDA ports on PDA, Laptops USB sticks • Remote Control in TV, VCR, Air-conditioner Port costs less than Rs. 1000 Talk at SASTRA

14. Bluetooth: Wireless PAN • Bluetooth (Named after Danish King Harold Bluetooth) • Based on Master-Slave concept • Short-range (10 meters) • Eliminate the need for cables • Operates in 2.4 GHz ISM band • 720 Kbps • Three modes of operation park/hold/sniff • Piconet & Scatternet (master+7 slaves) • Interference due to multiple piconets and IEEE 802.15.1 home/person LAN • To eliminate interference frequency hoping technique used • Ominidirectional with both voice & data M1 S2 S1 S1 S2 M 1/S1 Piconet 1 Piconet 2 Port costs about Rs. 2000 Talk at SASTRA

15. Wi-Fi: Wireless LAN (Hot Spot) • Wireless Fidelity based LAN • Most popular on Laptops • Replacement to wired LAN • Connectivity on the move • Short-range (100 meters) • Ad Hoc and Base station mode • Security provided at physical layer • Operates in 2.4 GHz and 5 GHz • Collection of IEEE standards 802.11a/b/g 11 Mpbs & 54 Mbps • Low range, requires more power hence not suitable for PDA’s • Difficult to control access & security • Set up is expensive Ad Hoc Net Access Point Net Talk at SASTRA

16. Wi-Max: Wireless MAN • Wireless Max • High Speed 40-70 Mbps • Mid-range (30 Kmeters) • Eliminate the need for cables • Saving of wired cost • Operates in 2.4 GHz ISM band • IEEE standard 802.16 Talk at SASTRA

17. Issues in Wireless Networking • Infrastructured networks • Handoff • location management (mobile IP) • channel assignment Talk at SASTRA

18. Issues in Wireless Networking Infrastructureless networks Wireless MAC • Security (integrity, authentication, confidentiality) • Ad Hoc Routing Protocols • Multicasting and Broadcasting Talk at SASTRA

19. Indoor Environments • Three popular technologies - High Speed Wireless LANs(802.11b (2.4GHz, 11 Mbps), 802.11a (5GHz, 54 Mbps & higher) - Wireless Personal area Networks PANs (IEEE 804.14) • HomeRF • Bluetooth, 802.15 - Wireless device networks • Sensor networks, wirelessly networked robots Talk at SASTRA

20. What is an Ad hoc Network • Collection of mobile wireless nodes forming a network without the aid of any infrastructure or centralized administration • Nodes have limited transmission range • Nodes act as a routers Talk at SASTRA

21. Ad Hoc Networks • Disaster recovery • Battlefield • ‘Smart’ office • Rapidly deployable infrastructure • Wireless: cabling impractical • Ad-Hoc: no advance planning • Backbone network: wireless IP routers • Network of access devices • Wireless: untethered • Ad-hoc: random deployment • Edge network: Sensor networks, Personal Area Networks (PANs), etc. Talk at SASTRA

22. Ad Hoc Network • Characteristics • Dynamic topologies • Limited channel bandwidth • Variable capacity links • Energy-constrained operation • Limited physical security • Applications • Military battlefield networks • Personal Area Networks (PAN) • Disaster and rescue operation • Peer to peer networks Talk at SASTRA

23. Security Challenges in Ad Hoc Networks • Lack of Infrastructure or centralized control • Key management becomes difficult • Dynamic topology • Challenging to design sophisticated & secure routing protocols • Communication through Radio Waves • Difficult to prevent eavesdropping • Vulnerabilities of routing mechanism • Non-cooperation of nodes • Vulnerabilities of nodes • Captured or Compromised Talk at SASTRA

24. Security • Challenges in ad hoc network security • The nodes are constantly mobile • The protocols implemented are co-operative in nature • There is a lack of a fixed infrastructure to collect audit data • No clear distinction between normalcy and anomaly in ad hoc networks • Secure the Routing Mechanism • A mechanism that satisfies security attributes like authentication, confidentiality, non-repudiation and integrity • Secure the Key Management Scheme • Robust key certification and key distribution mechanism Talk at SASTRA

25. Scalable, reliable, consistent, distributed service Services while on move services Sensor services exercise monitorbiometrics traffic information Calendar+ service Integrate dynamic traffic & schedule Doctor prescription servicetrack health indicatorsDoctor write prescription Follow me kiosk service receive and transmit messages Fridge & shopping serviceFridge records stockSuggests shopping based on recipeShopping guide in store Sensors mobile devices Talk at SASTRA

26. Tourist guide • Stuttgart tourist guide • Like MapQuest except on mobile device • Mapping local interests • Museums historical sites • Shopping & restaurants Sample Data • Small text with description, operating hours • Local map Talk at SASTRA

27. How it works • Info station • Island of wireless station • Embedded in area • Users have cheap low bandwidth components • Integrated to network with high quality connection • Requires some overlap to manage transition between stations for hand off • Scaleable by load balancing • Each center contains unique information • Overhead of communication • Initialize externally specified; adjusts quickly Talk at SASTRA

28. Map-on-the-move • Provide appropriate map • County resolution driving in car • Info stations small area high bandwidth • Remainder lower bandwidth Talk at SASTRA

29. Problems in a Mobile Environment • Variable Bandwidth • Disconnected Operation • Limited Power • Implications on distributed file system support? Talk at SASTRA

30. Constraints in mobile computing • PDA vs. Laptop vs. cell phones • Cellular modem connection: Failure prone • Space: office vs. city vs. county • Not continuous connectivity required • Data such as pictures text files not streaming audio and video • Heterogeneous devices Talk at SASTRA

31. MANET: Mobile Ad hoc Networks A collection of wireless mobile nodes dynamically forming a network without any existing infrastructure and the relative position dictate communication links (dynamically changing). From DARPA Website Talk at SASTRA

32. Rapidly Deployable Networks • Failure of communication networks is a critical problem faced by first responders at a disaster site • major switches and routers serving the region often damaged • cellular cell towers may survive, but suffer from traffic overload and dependence on (damaged) wired infrastructure for backhaul • In addition, existing networks even if they survive may not be optimized for services needed at site • significant increase in mobile phone traffic needs to be served • first responders need access to data services (email, www,...) • new requirements for peer-to-peer communication, sensor net or robotic control at the site • Motivates need for rapidly deployable networks that meet both the above needs ->recent advances in wireless technology can be harnessed to provide significant new capabilities Talk at SASTRA

33. Infostations Prototype: System for Rapid Deployment Applications • Outdoor Infostations with radio backhaul • for first responders to set up wireless communications infrastructure at a disaster site • provides WLAN services and access to cached data • wireless backhaul link • includes data cache • Project for development of: • high-speed short-range radios • 802.11 MAC enhancements • content caching algorithm & software • hardware integration including solar panels, antennas and embedded computing device with WLAN card Talk at SASTRA WINLAB’s Outdoor Infostations Prototype (2002)

34. Ad-Hoc Wireless Network • A flexible, open-architecture ad-hoc WLAN and sensor network testbed ... • open-source Linux routers, AP’s and terminals (commercial hardware) • Linux and embedded OS forwarding and sensor nodes (custom) • radio link and global network monitoring/visualization tools • prototype ad-hoc discovery and routing protocols 802.11b PDA Management stations Radio Monitor 802.11b Linux PC Forwarding Node/AP (custom) AP Commercial 802.11 Router network with arbitrary topology Compute & storage servers Sensor Node (custom) PC-based Linux router Talk at SASTRA

35. What is a WSN? Observer: The end user/computer Sensor: The device Phenomenon: The entity of interest to the observer • A network that is formed when a set of small sensor devices that are deployed in an “ad hoc fashion” no predefined routes, cooperate for sensing a physical phenomenon. • A Wireless Sensor Network (WSN) consists of base stations and a number of wireless sensors. • Is simple, tiny, inexpensive, and battery-powered Talk at SASTRA

36. Why Wireless Sensors Now? • Moore’s Law is making sufficient CPU performance available with low power requirements in a small size. • Research in Materials Science has resulted in novel sensing materials for many Chemical, Biological, and Physical sensing tasks. • Transceivers for wireless devices are becoming smaller, less expensive, and less power hungry (low power tiny Radio Chips). • Power source improvements in batteries, as well as passive power sources such as solar or vibration energy, are expanding application options. Talk at SASTRA

37. Typical Sensor Node Features • A sensor node has: • Sensing Material • Physical – Magnetic, Light, Sound • Chemical – CO, Chemical Weapons • Biological – Bacteria, Viruses, Proteins • Integrated Circuitry (VLSI) • A-to-D converter from sensor to circuitry • Packaging for environmental safety • Power Supply • Passive – Solar, Vibration • Active – Battery power, RF Inductance Talk at SASTRA

38. Sensor Node Hardware Sensor + Actuator + ADC + Microprocessor + Powering Unit + Communication Unit (RF Transceiver) + GPS • Portable and self-sustained (power, communication, intelligence). • Capable of embedded complex data processing. Talk at SASTRA

39. Sensors and Wireless Radio • Types of sensors: -Pressure, -Temperature -Light -Biological -Chemical -Strain, fatigue -Tilt • Capable to survive harsh environments (heat, humidity, corrosion, pollution etc). • No source of interference to systems being monitored and/or surrounding systems. • Could be deployed in large numbers. Talk at SASTRA

40. Wireless Sensor Networks • ZigBee Wireless Communication Protocol • Based on the IEEE 802.15.4 standard • Small form factor • Relatively Inexpensive • Low Power Consumption • Low Data Rate of Communication • Self Organising, Self-Healing…multi-hop nodes • Integrated Sensors • Ideal for Wireless Sensor Network Applications Talk at SASTRA

41. WSN APPLICATIONS • Potential for new intelligent applications: • Smart Homes • Process monitoring and control • Security/Surveillance • Environmental Monitoring • Construction • Medical/Healthcare • Implemented with Wireless Sensor Networks! Talk at SASTRA

42. Medical and Healthcare Appln Remote Databases Backbone Network Net Switch In Hospital Physician Net Switch Wireless Remote consultation Possibility for Remote consulting (including Audio Visual communication) Talk at SASTRA

43. Medical and Healthcare Applications Sensors equipped with BlueTooth Talk at SASTRA Source: USC Web Site

44. iBadge - UCLA • Investigate behavior of children/patient • Features: • Speech recording / replaying • Position detection • Direction detection / estimation (compass) • Weather data: Temperature, Humidity, Pressure, Light Talk at SASTRA

45. Other Examples • MIT d'Arbeloff Lab – The ring sensor • Monitors the physiological status of the wearer and transmits the information to the medical professional over the Internet • Oak Ridge National Laboratory • Nose-on-a-chip is a MEMS-based sensor • It can detect 400 species of gases and transmit a signal indicating the level to a central control station • VERICHIP: Miniaturised, Implanted, Identification Technology Talk at SASTRA

46. Structural Health Monitoring Accelerometer board prototype, Ruiz-Sandoval, Nagayama & Spencer, Civil E., U. Illinois Urbana-Champaign Semi-active Hydraulic Damper (SHD), Kajima Corporation, Japan Model bridge with attached wireless sensors, B.F. Spencer’s Lab, Civil E., U. Illinois U-C Talk at SASTRA

47. ST Pollutants monitored by sensors in the river Sensors report to the base monitoring station Application in Environment Monitoring • Measuring pollutant concentration • Pass on information to monitoring station • Predict current location of pollutant volume based on various parameters • Take corrective action Talk at SASTRA

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49. Vehicular Traffic Control Talk at SASTRA

50. VMesh: Distributed Data Sensing, Relaying, & Computing via Vehicular Wireless Mesh Networks Project at The University of California, Davis US FCC allocated 5.850 to 5.925 GHz dedicated short range communication (DSRC) Road side to Vehicle Vehicle to vehicle communication Talk at SASTRA