wireless sensor network health diagnostic
Post on 23-Feb-2016
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Wireless Sensor Network Health
DiagnosticDavid Rogers, Stu Andrzejewski,
Kelly Desmond, Brad Garrod
Sensors outnumber people
Receiving correct data Communicating across network nodes
accurately Proper operation
But how do we know they are working correctly?
EKG graphs
How can a sensor fail?
Malicious Nodes
Environmental FactorsInsufficient Node Power
Can destroy…◦ Health/Lives
Air Pollution◦ Equipment
Automobile◦ Environment
Forest Fire
Implications of Sensor Failure
Overall failing sensors can lead to millions of dollars in damage!
1. Configure a sensor network2. Collect metrics about the network3. Create human/network interface 4. Analyze correlations between metrics and
node failure5. Validate metrics and test for accuracy
Steps for solving the problem
1. Configure a sensor networkA. Define network topologyB. Identify vital components of sensor
hardwareC. Select sensor network hardware
2. Collect metrics about the network3. Create human/network interface 4. Analyze correlations between metrics and
node failure5. Validate metrics for accuracy
Steps for solving the problem
Mesh Topology
◦ Nodes communicate directly to other nodes without the need of a cluster head
1A. Network topology Star Topology
◦ Cluster head controls data communication between nodes
• Advantages• Better
performance• Benefits from
centralization• Isolation of
nodes• Simple
• Disadvantages
• Centralization dependency
• Expensive• Central hub
failure = network failure
• Advantages• Self- healing• Less traffic
load• Isolation of
node faults
• Disadvantages• Complexity• Installation• Price
What kinds of information from the sensor would be useful to understand how well they are functioning?
1B. Criteria for sensor nodes
◦ Battery life◦ Current draw◦ RF transmission power◦ Received signal strength◦ Processor load◦ Memory utilization
1C. Proposed Sensor Network Kits Powercast P2110-
EVAL
Features◦ Low-power◦ Battery-free (RF Power)◦ Pre-loaded, custom firmware◦ Temperature, Humidity, and Light
Sensors ◦ External Sensor Port◦ RSSI Calculation◦ USB interface for power and data
SunSPOT
Features◦ Embedded Development Platform ◦ Extremely flexible hardware and software
package◦ Easy to program - Java top to bottom ◦ Connected – Wireless Communication ◦ Mobile & Secure◦ Built in Lithium Ion battery charged
through USB◦ Able to sense and affect surroundings◦ Built-in high grade ECC public key
cryptography
1. Configure a sensor network2. Collect metrics about the network
A. What to monitor?3. Create human/network interface 4. Analyze correlations between metrics and
node failure5. Validate metrics for accuracy
Steps for solving the problem
2A. What to monitor? External
◦ Humidity◦ Temperature◦ Light◦ Sound◦ Motion◦ Pressure◦ Vibration◦ Electrical Fields
Internal◦ Current Draw◦ Battery Life◦ Voltage Reported◦ RF Transmission◦ Received Signal
Strength◦ Channel Availability◦ Processor Load◦ Memory Utilization
(RAM)
1. Configure a sensor network2. Collect metrics about the network3. Create human/network interface
A. Identify ideal communication protocolB. Create graphical user interface
4. Analyze correlations between metrics and node failure
5. Validate metrics for accuracy
Steps for solving the problem
Must be able to communicate with sensors remotely
IEEE 802.15.4◦ Includes ZigBee, Bluetooth, Wifi◦ Uses CSMA/CA for secure communications
Nodes only transmit when the channel is idle◦ Devices also include power management
functions such as link quality and energy detection.
3A. Identify proper communication protocols
Create user-friendly display◦ Handles all incoming data packets from sensor
nodes behind the scenes The data will be displayed in a way for easy
evaluation of the sensor data stream and network health
◦ Alerts the operator when failures have occurred or are occurring
3B. Create graphical user interface
1. Configure a sensor network2. Collect metrics about the network3. Create human/network interface 4. Analyze correlations between metrics
and node failure5. Validate metrics for accuracy
Steps for solving the problem
Determine the most important metrics that identify node failure
Algorithms for detecting malfunctioning nodes◦ Majority Voting◦ Thresholding◦ Weighted average
Understanding associations between multiple metrics◦ Attempting to measure current draw while the
sensor is transmitting back to the cluster head
4. Analyze correlations between metrics and node failure
1. Configure a sensor network2. Collect metrics about the network3. Create human/network interface 4. Analyze correlations between metrics and
node failure5. Validate metrics for accuracy
Steps for solving the problem
Design a test plan to ensure a high quality health diagnostic◦ Series of controlled experiments
Statistically validate chosen algorithms◦ Reduce false positives and false negatives
5. Validate metrics for accuracy
Monitoring sensor health is vital for proper function of a wireless sensor network
Many external and internal factors attribute to sensor node failure
By designing algorithms and a test plan to systematically validate failures, important metrics relating to the health of a wireless sensor network can be determined
Conclusion
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