Energy Saving In Sensor Network Using Specialized Nodes

1. Energy Saving In Sensor Network Using Specialized Nodes Shahab Salehi EE 695

2. What is a Sensor Network • Small wireless nodes • Functionality • Detect events • Relay information to the Base Station • Applications: monitoring of wildlife, intruders, earthquakes, fire, contaminants etc.

3. Issues • Number of nodes • In the range of Millions • Need to configure themselves automatically once deployed • No Infrastructure • Power Consumption

4. Power Consumption Problem • Once the nodes are deployed, it is not an option to change the battery • Environment • Cost • Number of nodes deployed • Important to be able to save as much energy as possible

5. Nature Of Network Sensor • They are usually application specific • Event driven • Time driven • Can use this as an advantage to minimize power consumption • Sampling Temperature every 1 min. • Network does not need to send data unless an even has occurred

6. Energy Saving Methods • Using energy efficient routing protocols • Advantages • Used with existing hardware • Can find the shortest or less costly path • Disadvantages • Have to come up with a new protocol

7. Energy Saving Methods (Cont.) • Use of processors sleep mode • Sleep, wake up every 1 minute, take the temperature, send data, Go back to sleep • Use of external sensors • Processors is sleep, but the sensor is on and detecting events. • Sensor uses minimal power, therefore saving power while there is no event

8. Energy Saving Methods (Cont.) • Dynamic transmission power B A C

9. Energy Saving Methods (Cont.) • Change Transmission power based on SNR B A C

10. Proposed Method • Use of two different type of nodes during deployment • Sensor nodes • Larger size Transmitter nodes for data transmission • Sensor nodes • Small mobile devices • Sensing • Event detection • Transmission

11. Proposed Method (Cont.) • Transmitter nodes • Equipped with larger batteries • Have longer transmission range • Used only for transmitting data to base station • Acts as a highway for the stream of data from the Sensor nodes

12. Proposed Method (Cont.) • Advantages • Sensor nodes will spend less time transferring other nodes packets • Nodes do not need to search for a path to Base Station, just to the nearest Transmitter Node • Speed of transmission increases • Instead of going though many small nodes, data will take fewer hops and goes through few larger nodes

13. Proposed Method (Cont.) • Larger nodes forming a path to Base Station BS

14. Deployment Steps • The Nodes are thrown out of the plane • Ex. Border Intrusion Detection • Base Station Sends a signal to its nearest Transmitter node • Giving it a routing number starting from 1 • From there each Transmitter node identifies its neighbor (s) and if does not have a routing number it will be given one in an increasing order until all transmitter nodes have routing number

15. Deployment Steps (Cont.) • Purpose of the route number is for the transmitter node to know where it needs to send the packets to 3 12 5 10 14 16 7 BS 15 1 2 8 6 9 13 11 4

16. Deployment Steps (Cont.) • Since the placement of the Transmitter nodes are random • The distance between the Transmitter nodes could be longer than their range • Two or more Transmitter nodes are placed very close together and share the same neighbors

17. Deployment Steps (Cont.) • If the distance between two Transmitter node is longer than their range • They search for a Sensor node that is with in their range and use it as intermediate transmitting stage

18. Deployment Steps (Cont.) • If two or more Transmitting nodes share same neighbors • One of them on random give a sleep command to their others and will not wake it up until needed

19. Deployment Steps (Cont.) • If at anytime one of the Transmitter node fail or dies, the Sensor nodes will take over its place and try to find the nearest Transmitter node • If all the Transmitter nodes die, Sensor node will relay the data using each other

20. Deployment Steps (Cont.) • Optimal number of Transmitter nodes? • Length of area being covered • Range of each Transmitter nodes • How much redundancy you want

21. Deployment Steps (Cont.) • Ex. Border Security • 2000,000 m • Range of 100m • If the nodes are perfectly setup and operate • 2000,000 / 100 = 20,000 Nodes • Assume 2/3 of range • 2000,000 / (2/3 * 100) = 30,000 Nodes • Redundancy • 30,000 * 2 = 60,000 Nodes

22. Conclusion • By using Transmitter nodes • Add to the life of the network • Speed up the data collection processes • Faster event notification • Can be easily used with other energy saving methods to increase networks life

23. “Simulation” • Sensor Node • 1 msg / s • Message length 20 bytes , 5 ms to Tx/Rx • Tx = 0.4 mA Rx=0.246 mA • Transmitter Node • Tx = 0.52 mA Rx=0.31 mA BS

24. “Simulation” • Based on Sensor Nodes shortest path • 43 hops • (43 * .4) + (43 * .246) = 27.78 mA • Based on Transmitter Node • 2 hops on Sensor Nodes • 16 hops on Transmitter Nodes • (2*.4)+(2*.246)+(16*.52)+(16*.31) = 14.57 mA

25. Questions?