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

Energy Saving In Sensor Energy Saving In Sensor Network Using Specialized Network Using Specialized

NodesNodes

Shahab SalehiShahab Salehi

EE 695EE 695

What is a Sensor NetworkWhat 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.

IssuesIssues

Number of nodesNumber of nodes In the range of MillionsIn the range of Millions

Need to configure themselves Need to configure themselves automatically once deployedautomatically once deployed

No InfrastructureNo Infrastructure

Power ConsumptionPower Consumption

Power Consumption ProblemPower Consumption Problem

Once the nodes are deployed, it is not an Once the nodes are deployed, it is not an option to change the batteryoption to change the battery EnvironmentEnvironment CostCost Number of nodes deployedNumber of nodes deployed

Important to be able to save as much Important to be able to save as much energy as possibleenergy as possible

Nature Of Network SensorNature Of Network Sensor

They are usually application specificThey are usually application specific Event drivenEvent driven Time drivenTime driven

Can use this as an advantage to minimize Can use this as an advantage to minimize power consumptionpower consumption Sampling Temperature every 1 min.Sampling Temperature every 1 min. Network does not need to send data unless Network does not need to send data unless

an even has occurredan even has occurred

Energy Saving MethodsEnergy Saving Methods

Using energy efficient routing protocolsUsing energy efficient routing protocols AdvantagesAdvantages

Used with existing hardwareUsed with existing hardware

Can find the shortest or less costly pathCan find the shortest or less costly path DisadvantagesDisadvantages

Have to come up with a new protocolHave to come up with a new protocol

Energy Saving Methods (Cont.)Energy Saving Methods (Cont.)

Use of processors sleep modeUse of processors sleep mode Sleep, wake up every 1 minute, take the Sleep, wake up every 1 minute, take the

temperature, send data, Go back to sleeptemperature, send data, Go back to sleep

Use of external sensorsUse of external sensors Processors is sleep, but the sensor is on and Processors is sleep, but the sensor is on and

detecting events. detecting events. Sensor uses minimal power, therefore saving Sensor uses minimal power, therefore saving

power while there is no eventpower while there is no event

Energy Saving Methods (Cont.)Energy Saving Methods (Cont.)

Dynamic transmission powerDynamic transmission power

A

B

C

Energy Saving Methods (Cont.)Energy Saving Methods (Cont.)

Change Transmission power based on Change Transmission power based on SNRSNR

A

B

C

Proposed MethodProposed Method

Use of two different type of nodes during Use of two different type of nodes during deploymentdeployment Sensor nodesSensor nodes Larger size Transmitter nodes for data transmissionLarger size Transmitter nodes for data transmission

Sensor nodes Sensor nodes Small mobile devices Small mobile devices Sensing Sensing Event detection Event detection TransmissionTransmission

Proposed Method (Cont.)Proposed Method (Cont.)

Transmitter nodes Transmitter nodes Equipped with larger batteriesEquipped with larger batteries Have longer transmission rangeHave longer transmission range Used only for transmitting data to base stationUsed only for transmitting data to base station

Acts as a highway for the stream of data Acts as a highway for the stream of data from the Sensor nodesfrom the Sensor nodes

Proposed Method (Cont.)Proposed Method (Cont.)

AdvantagesAdvantages Sensor nodes will spend less time transferring Sensor nodes will spend less time transferring

other nodes packetsother nodes packets Nodes do not need to search for a path to Nodes do not need to search for a path to

Base Station, just to the nearest Transmitter Base Station, just to the nearest Transmitter NodeNode

Speed of transmission increasesSpeed of transmission increasesInstead of going though many small nodes, data Instead of going though many small nodes, data will take fewer hops and goes through few larger will take fewer hops and goes through few larger nodesnodes

Proposed Method (Cont.)Proposed Method (Cont.)

Larger nodes forming a path to Base Larger nodes forming a path to Base StationStation

BS

Deployment StepsDeployment Steps

1.1. The Nodes are thrown out of the planeThe Nodes are thrown out of the plane1.1. Ex. Border Intrusion DetectionEx. Border Intrusion Detection

2.2. Base Station Sends a signal to its nearest Base Station Sends a signal to its nearest Transmitter nodeTransmitter node

1.1. Giving it a routing number starting from 1Giving it a routing number starting from 1

3.3. From there each Transmitter node identifies its From there each Transmitter node identifies its neighbor (s) and if does not have a routing neighbor (s) and if does not have a routing number it will be given one in an increasing number it will be given one in an increasing order until all transmitter nodes have routing order until all transmitter nodes have routing numbernumber

Deployment Steps (Cont.)Deployment Steps (Cont.)

Purpose of the route number is for the Purpose of the route number is for the transmitter node to know where it needs to transmitter node to know where it needs to send the packets to send the packets to

BS 216

53

4

12

11

10

98

7

13

1415

16

Deployment Steps (Cont.)Deployment Steps (Cont.)

Since the placement of the Transmitter Since the placement of the Transmitter nodes are randomnodes are random The distance between the Transmitter nodes The distance between the Transmitter nodes

could be longer than their rangecould be longer than their range Two or more Transmitter nodes are placed Two or more Transmitter nodes are placed

very close together and share the same very close together and share the same neighborsneighbors

Deployment Steps (Cont.)Deployment Steps (Cont.)

If the distance between two Transmitter If the distance between two Transmitter node is longer than their rangenode is longer than their range They search for a Sensor node that is with in They search for a Sensor node that is with in

their range and use it as intermediate their range and use it as intermediate transmitting stagetransmitting stage

Deployment Steps (Cont.)Deployment Steps (Cont.)

If two or more Transmitting nodes share If two or more Transmitting nodes share same neighborssame neighbors One of them on random give a sleep One of them on random give a sleep

command to their others and will not wake it command to their others and will not wake it up until needed up until needed

Deployment Steps (Cont.)Deployment Steps (Cont.)

If at anytime one of the Transmitter node If at anytime one of the Transmitter node fail or dies, the Sensor nodes will take fail or dies, the Sensor nodes will take over its place and try to find the nearest over its place and try to find the nearest Transmitter nodeTransmitter node

If all the Transmitter nodes die, Sensor If all the Transmitter nodes die, Sensor node will relay the data using each othernode will relay the data using each other

Deployment Steps (Cont.)Deployment Steps (Cont.)

Optimal number of Transmitter nodes?Optimal number of Transmitter nodes? Length of area being coveredLength of area being covered Range of each Transmitter nodesRange of each Transmitter nodes How much redundancy you wantHow much redundancy you want

Deployment Steps (Cont.)Deployment Steps (Cont.)

Ex. Border SecurityEx. Border Security 2000,000 m2000,000 m Range of 100mRange of 100m If the nodes are perfectly setup and operate If the nodes are perfectly setup and operate

2000,000 / 100 = 20,000 Nodes2000,000 / 100 = 20,000 Nodes Assume 2/3 of rangeAssume 2/3 of range

2000,000 / (2/3 * 100) = 30,000 Nodes2000,000 / (2/3 * 100) = 30,000 Nodes RedundancyRedundancy

30,000 * 2 = 60,000 Nodes30,000 * 2 = 60,000 Nodes

ConclusionConclusion

By using Transmitter nodesBy using Transmitter nodes Add to the life of the networkAdd to the life of the network Speed up the data collection processesSpeed up the data collection processes

Faster event notificationFaster event notification Can be easily used with other energy saving Can be easily used with other energy saving

methods to increase networks lifemethods to increase networks life

““Simulation”Simulation”

Sensor NodeSensor Node 1 msg / s1 msg / s Message length 20 bytes , 5 ms to Tx/RxMessage length 20 bytes , 5 ms to Tx/Rx Tx = 0.4 mATx = 0.4 mA Rx=0.246 mARx=0.246 mA

Transmitter NodeTransmitter Node Tx = 0.52 mATx = 0.52 mA Rx=0.31 mARx=0.31 mA

BS

““Simulation”Simulation”

Based on Sensor Nodes shortest pathBased on Sensor Nodes shortest path 43 hops43 hops (43 * .4) + (43 * .246) = 27.78 mA(43 * .4) + (43 * .246) = 27.78 mA

Based on Transmitter NodeBased on Transmitter Node 2 hops on Sensor Nodes2 hops on Sensor Nodes 16 hops on Transmitter Nodes16 hops on Transmitter Nodes (2*.4)+(2*.246)+(16*.52)+(16*.31) = 14.57 mA(2*.4)+(2*.246)+(16*.52)+(16*.31) = 14.57 mA

Questions?Questions?