Sensor networks CODE BLUE Sensor Networks for Emergency Response Challenges and Opportunities New class of devices having the potential to revolutionize the capture, processing and communication of critical data for use by first responders. Consists of small, low-power and low-cost devices with limited computational and wireless communication capabilities. CODE BLUE A software infrastructure built on sensor networks that addresses the challenges about the limitations of sensor networks in use of emergency situations. Is an integration of sensor nodes and other devices into a disaster response setting. Facilitates: Ad hoc network formation Resource naming and discovery Security In-network aggregation of sensor-produced data Challenges CODE BLUE has to face: DISCOVERY AND NAMING Establish the communication pathway between the vital sign sensors and first responders. Device naming should be application centric. Something more than a low-level network address required. Discovery process should be decentralized to prevent failures at a single node.
Challenges (cont.) ROBUST ROUTING Disaster scenario devices might need to communicate with other devices outside their immediate radio range. Ad hoc routing techniques preferred. Multicast: a vital sign sensors can send information to multiple types of receivers. PRIORITZATION OF CRITICAL DATA Limited bandwidth on low-power radios. Information needs to be selective. SECURITY Big concern in wireless communication. Privacy and patient profiles. Can t rely on a predeployed public key infrastructure. Tracking system How to track patients and rescuers efficiently. Should be able to adapt many types of signal (GPS, RF signal )
CODE BLUE CODE BLUE (Cont.) Completed Components Code Blue information plane addresses the challenges previously described Facilitates the discovery process between devices. Flexible naming scheme Authentication and encryption provisions Credential establishment service Location tracking An improving system Wireless vital sign sensor: Run on motes: Very simple-architecture chips low power, very simple OS (for concurrency and resource management in sensor networks). No TCP/IP or ARP Some motes in use: Pulse oximeter: captures a patient s heart rate and blood oxygen saturation EKG: heart s electrical activity in more severely injured patients Handheld devices (carried by first responder) Motes described from previous slide Wireless Vital Sign Sensor system: Handheld devices Carried by first responder Can capture information from multiple motes. Since motes have ids, the responder can identify the patients.
SECURITY IMPLEMENTATION Defend adversaries on spoofing, capturing information Conventional login authentication not practical Public-key architecture too heavy for the framework Motes only has 4kb RAM, cannot store so many RSA public keys. Use: ECC (Elliptic Curve Cryptography) on Mica2. Smaller keys (163 bit) can be generated in 35 seconds Future: leverage complex computation of keys to other more powerful devices (sensor nodes have to decide which device to trust). LOCATION TRACKING - MoteTrack RF-based Beacons (can replace smoke detectors) populated in the area and have a subset of signatures. Mobile node waiting for signature (known, fixed locations previously set up) and send that information to the beacons closest to it to know where it is. MoteTrack (Cont.) MoteTrack (Cont.) Decentralized Robustness Mobile nodes request information about the reference-signature bases. It relies on the beacon message with the strongest Received Signal Strength Indication (RSSI) to calculate its location.
Conclusion Other subsystems are being developed on Code Blue (device discovery, traffic prioritization, robust routing ) Open question: Leverage of computational power to other devices.