RF 2 ID: A Reliable Middleware Framework for RFID Deployment

RF2ID: A Reliable Middleware Framework for RFID Deployment

Nova AhmedRajnish Kumar

Umakishore Ramachandran

College of ComputingGeorgia Institute of Technology

RFID Devices

• Opportunity– Low cost sensor solution– No line of site problem– Industry interest in large scale deployment

• Challenges– Error prone in nature– Vulnerable to physical environment– Large amounts of data

Application Scenario

Item Tracking– Tagged Items are moving– Readers are static– Ex: Warehouse Distribution , Airport Baggage Claim Scenario

Item Location– Tagged Items are static– Readers are moving– Ex: Disaster Scenario

A notion of Path in different scenarios

Sources Destinations

Physical path for item flow

RFID readers

Tagged item

System Architecture

A Path based System Virtual Readers (VRs) – Distributed Computational Element Physical RFID Readers (PRs) – Sensor Input Device Path Server and Name Server – Decision Making Elements

Virtual Reader 1

Virtual Reader 2

Application

Name Server

Path Server

Virtual Reader n-1

Virtual Reader n

Physical Reader Interface

System Interface

RFID Readers

Physical Route in a Warehouse System

SourceA

SourceB

DestinationD

DestinationC

v

v

DestinationE

RFID reader

Flow of item on conveyor belt

Range of VR

VR1 VR2 VR4

VR3

Architectural Features meeting Design Goals

• Reliability– A virtual reader for a number of

physical readers– Path using virtual readers

• Load shedding– VRs can drop data

• Multiple flows– Paths are shared

Virtual Reader 1

Virtual Reader 2

Application

Name Server

Path Server

Virtual Reader n-1

Virtual Reader n

Physical Reader Interface

System Interface

RFID Readers

Logical Connectivity of Virtual Readers

• Data Management • Path Management • Query Management

Implementation

Prototype implementation complete Virtual Reader Paths Physical readers and simulated physical

readers Tunable parameters to change reader accuracy

– tag distance– tag angular position– reader power level

– VRs Implemented as nodes in a cluster communicating using MPI

Physical Reader Performance (1)

Distance Dependency Angular Position Dependency

Angular Position: 90 DegreeNumber of Reader Antenna : 2Reader Power: 31.5 dB

Distance: 15 inchesNumber of Reader Antenna : 2Reader Power: 31.5 dB

0

1

2

3

4

5

6

7

0 30 60 90 120 150 180

Angle among tag and antenna

Tota

l num

ber

of d

etec

ted

tags

Detected tags among1 tag

Detected tags among tags

Detected tags among3 tags

Detected tags among4 tags

Detected tags among5 tags

Detected tags among6 tags

Number of detected tags with respect to distance

0

1

2

3

4

5

6

0 20 40 60 80

Tag distance from antenna (perpendicular to antenna)

Num

ber

of to

tal t

ags

Number of detected tagsin 1 tag

Number of detected tagsin 2 tags

Number of detected tagsin 3 tags

Number of detected tagsin 4 tags

Number of detected tagsin 5 tags

ALR 9800 with 2 antennas from Alien Technologies

Physical Reader Performance (2)

0

2

4

6

8

0 20 40 60 80 100

Observation time (seconds)N

um

be

r o

f de

tect

ed

tag

s

Attenuation Dependency Time Dependency

Angular Position: 90 DegreeNumber of Reader Antenna : 2Number of Tags: 6

Reader to Tag Distance: 15 inchesNumber of Reader Antenna : 2Reader Power: 31.5 dBNumber of Tags: 6

0

1

2

3

4

5

6

0 3 6 9 12

RF Attenuation (dB)

Nu

mb

er o

f d

etec

ted

tag

s

Detected Tags(among 6 tags)

Improving Reliability using a Single VR

Number of Reader Antenna : 2Reader to Route Distance: 10 inchesReader Power: 31.5 dB

VR

Reader1 Reader2

0

10

20

30

40

50

60

70

30 60 90 120 150 180 210 240 270 300

Number of tags

Fal

se N

egat

ive

(%)

PR1

PR2

Path

Improving Reliability using Multiple VRs (path)

Total Number of Tags : 10000Simulation Iteration: 100

VR

Reader

0

10

20

30

40

50

60

70

80

90

100

0 5 10 15 20 25 30

Num ber of Virtual Readers

Nu

mb

er o

f F

alse

Neg

ativ

e T

ags

(%) Reader Accuracy40%

Reader Accuracy 50% Reader Accuracy 60% Reader Accuracy 70% Reader Accuracy 80% Reader Accuracy 90%

Conclusions

• Experiments showing unreliability of RFID devices

• A middleware architecture for improving reliability

• A prototype implementation• Performance results showing improvement in

reliability

Future Work

• Implementing the full functionality of the architecture

• Detailed performance analysis using more physical readers

• GUI base User Interface for RF2ID deployment

Thanks to RF2ID group members

Robert Steven French Echezona Ukah Vladimir Urazov