Installation and Evaluation of RFID Readers on Moving Vehicles
description
Transcript of Installation and Evaluation of RFID Readers on Moving Vehicles
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RFID applications◦ RFID-enabled vehicular applications
RFID system◦ RFID read performance
Installation of RFID system on vehicle Road test Conclusion
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What is RFID?◦ Identify physical objects
through a radio interface
◦ Identification? Assign ID to each object Bar code, license plate, student ID
How does RFID work?◦ RFID tag + RFID reader + antenna◦ Backscattering coupling (UHF)
Chip
Antenna
02.3DFEX4.78AF51
EasyToll card #816
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Tag type
Radio frequency range www.hitachi.com & www.vicariousconversations.com
Passive tag Active tag
Power No power source Internal battery
Pros Small & cheap (~10cents)Long radio range (~150m) & high performance
Cons Short radio range (~10m)Expensive & limited lifetime
FrequencyHF UHF Microwave
13.56MHz 433.92MHz 860-960MHz 2.45GHz
Range < 60Cm 50~100Cm < 3.5m, <10m 1m
Tag Passive Active Passive/Active Passive/Active
Property- Cheap reader- Short range
- Real-time tracking- Cheapest- Multiple-tag contact
- Sensitive to noise
Contact time Slow --------------------------------- Fast
Robustness(Sensitivity)
Robust --------------------------------- Sensitive
Tag size Big --------------------------------- Small
Application- Library books- Access Control
- Container- Real-time location tracking
- Automatic tolling- Supply chain tracking
- Asset tracking- Forgery avoidance
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Framed slotted Aloha (FSA)
Slot .. .. .
CW Query CyclePower down
CW Query CyclePower down .. .. ..
A response from one RFID tag
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Methodology of data producer/consumer◦ RFID tag
Stores data in memory, which is provided to RFID readers A data producer
◦ RFID reader Obtains RFID data from tags and utilizes it for further programs A data consumer
Each vehicle is a data producer !!
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Tag on vehicle (data producer)◦ Readers are on the roadside◦ Automatic toll collection◦ Intelligent traffic signal system◦ Electronic license plate◦ Priority lane management
Lane reservation and enforcement
www.ti.com
Reservation/Enforcement
SystemEnforce
Enforce
ReserveReserve
RFID Reader/Camera
High-Priority Lane
Low-PriorityLanesLane Entrance
AssistanceSystem
cs.rutgers.edu
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Reader on vehicle (data consumer)◦ Tags on the roadside units (road surface, sign post,
direction sign)◦ RFID positioning and Road beacon system (RBS)◦ Lane-level GPS (Donath’06)
RFID tags along each lane contains useful data (e.g., position) Intersection collision avoidance, Enhancement of driver’s situation awareness, Lane by lane incident management
RFID tag
RFID reader
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Tag/reader on vehicle (data prosumer)◦ Intelligent priority lane management◦ Peer localization
RFID tag
RFID reader
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Challenges◦ High vehicle speed
Faster than 100Km/h on a freeway
◦ Short communication distance Much less chance of RFID communication
◦ Random mobility of reader Reader position affects performance
significantly than tag placement Random fading effects
3m~4m
0.3m
RFID tag
RFID reader
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Motivation◦ Initial deployment of RFID reader/tag is important for
better performance◦ Necessary to measure performance in a real test road
In this work, we◦ Install RFID reader on a vehicle and tags on a road
surface◦ Evaluate RFID read performance in a laboratory
environment◦ Propose antenna diversity and tag multiplicity for
improvement◦ Conduct a road test to study feasibility of the system
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RFID Reader
RFID Reader Antenna RFID Tag
Antenna
EEPROM
Data
Energy
RFID Communication
Server
RFID reader
FrequencyRF powerRead distanceModulationRadio access
910~914MHz4w EIRP~5mASKFHSS
RFID reader antenna
AngleGainSize
60°(3dB)6 dBi215x420x55
RFID tagDataData rateMax pause time
64bit256kbps62.5ms
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RFID read area◦ Size and moving speed
h cm
θ° 68°Side view
h cm
68°
RFID Reader Antenna
RFID Reader Antenna
Front viewRead area
Read area
1X cm
2X cm
For instance, if h=37.5cm and θ=45°, then X1=58.58cm and X2=185.63cm
Speed [km/h]
Computed [ms]
Measured [ms]
10 665 360
20 332 180
30 222 120
40 166 90
50 133 72
60 111 60
70 95 51
80 83 45
90 74 40
100 67 36
RFID read area
Moving speed of RFID area
Measured X2≒100cm (1m)
RFID communication should occur in 1m read area within 36m
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Read latency◦ Time period when one RFID communication occurs◦ Measured 38.39ms on average
Mostly due to the maximum pause time of the tag: 62.5ms
◦ However, RFID read area moves at 36ms > 38.39ms Even 60ms at 60km/h < 62.5ms
RFID read rate
<- 36ms
38.39ms
# of tags successfully read = -----------------------
total # of tags deployed
High possibility of RFID communication failure
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Experiment setup RFID reader antenna
◦ Height◦ Pitch angle◦ Antenna diversity
RFID tag◦ Yaw angle ◦ Pitch angle◦ Tag multiplicity
Result
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Target performance◦ 0.5m of read area and 18m of read latency
Height of RFID reader antenna h=30cm◦ Similar performance in h=20~40cm◦ Height of the test vehicle is 30cm
Installation◦ RFID reader antenna & RFID tag
30°of tag yaw angle and 30°of antenna pitch angle 0.5m
RFID tag
18ms of read latency
RFID reader antenna
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Pitch angle◦ Varying pitch angle of the antennas◦ Measure the read area given 18ms of read latency◦ 30° of pitch angle
60°
0°Floor
21cm
70cm
Side view
Pitch angle of antenna Length of read area [cm]
50º40º
73.8972.3854.62
74.40
20º
68.95
30º
60º
21cm
10°20°30°
40°
10º
70º
0º 50.86
65.5866.77
50°
70° of pitch angle
30cm
0°10°
20°30°40°50
°60°70°
RFID Reader Antenna
RFID tags are attached on the floor with 0°
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Antenna diversity◦ Install one and dual antenna(s)◦ Measure the read area given 18ms of read latency
RFID Tag
RFID Reader Antenna
43 cm
80 c
m
78 c
m
RFID Reader Antenna 1
RFID Reader Antenna 2
65 cm
3m2m
1.5m
1 Antenna
RFID Tag
2 Antennas
0.86m
1.3m
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Yaw angle and pitch angle◦ Measure the read latency given 0.5m of the read area◦ Both are set 0°
RFID Reader
Antenna
Yaw angle (front view)
Yaw angle
RFID Tag
Floor
30cm
Pitch angle
Pitch angle (side view)
Yaw angle
0° 30° 60° 90° 120° 150° 180°
Read latenc
y44.3 44.2 x x x 45.1 46.9
30° of reader antenna
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Tag multiplicity◦ To mitigate effect of the random pause time◦ Measure the read latency given 0.5m of the read area◦ Cluster model 3 having 3 or 4 member tags
Cluster 1 Cluster 2 Cluster 3 Cluster 4
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RFID communication successfully occurs within 0.8m of RFID read area and 18ms of read latency
Antenna diversity and tag multiplicity◦ Showed improved performance
Estimation of the maximum vehicle speed◦ At which RFID communication can occur◦ 161.7km/h◦ Equivalent to previous researches
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RFID Tag RFID Reader Antenna
RFID Reader
Server
Deployment parametersTest1 Test2 Test3 Test4 Test5 Test6
# of antenna 1 2 2 2 2 2
# of member tags 1 1 3 4 3 4
RFID tag interval 2m 2m 2m 2m 5m 5m
Maximum speed [km/h] ~100 ~80 ~80 ~80 ~80 ~100
Test scenarios with variables
RFID reader antenna
RFID tag
Number 1 or 2 Yaw 0°
Height 30cm Pitch 0°
Pitch 30° Member tags 1, 3, or 4
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Effect of antenna diversity◦ Proof of concept in terms of width◦ Reduced length does not affect performance much
Average duplication read
Average read rate
3m2m
1.5m
1 Antenna
RFID Tag
2 Antennas
0.86m
1.3m
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Effect of tag multiplicity◦ Tag cluster outperforms single tag (Test 2, 3, and 4)◦ Tag interval influences performance (Test 3 and 5)
In particular, at high speed
◦ Duplication read dramatically decreases at high speed
10 20 30 40 50 60 70 80 90 1000
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Vehicle Speed [km/h]
Ave
rage
Dup
lica
tion
Rea
d [n
umbe
r]
Average duplication read
4 Tags, 5m Interval (Test 6)
1 Tag, 2m Interval (Test 2)3 Tags, 2m Interval (Test 3)4 Tags, 2m Interval (Test 4)3 Tags, 5m Interval (Test 5)
10 20 30 40 50 60 70 80 90 1000
10
20
30
40
50
60
70
80
90
100
Vehicle Speed [km/h]
Ave
rage
Rea
d R
ate
[%]
Average read rate
4 Tags, 5m Interval (Test 6)
1 Tag, 2m Interval (Test 2)3 Tags, 2m Interval (Test 3)4 Tags, 2m Interval (Test 4)3 Tags, 5m Interval (Test 5)
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Summary◦ RFID-enabled vehicular applications◦ On-board RFID reader system◦ Experiment
In a laboratory RFID reader antenna and RFID tag
On a test road
Contribution◦ A different approach to RFID-enabled vehicular system◦ Address antenna diversity and tag multiplicity
The newest topics for performance improvement
◦ Experiment data from a real test bed