This report studies various technologies which can be used for people tracking and crowd management. During any pilgrimage session, the events like losing a group member, medical emergencies, and stampede are very common. In case of disasters like flood, fire, earthquake pilgrims are often left stranded as they have a little knowledge about that area. To address these concerns, the authorities need information about the location and direction of movement of the pilgrims. Sometime, it may be necessary to identify a person in cases like a lost child, unconscious or dead person. Researchers have proposed a number of solutions using the wireless technology which includes RFID tags, NFC, GPS, Bluetooth and Wi-Fi. An introduction about the technologies and how they can be used to design systems for people identification and tracking is presented. The various systems using a set of technologies have been studied in terms of their effectiveness and the cost.
A Study of Wireless Technology Based Pilgrim Tracking Systems
1. A Study of Wireless Technology
Based Pilgrim Tracking Systems
Seminar Presentation
Presented by:-
Deepak Kumar
IDD-CSI
10211009
Under the guidance of:-
Dr. Dhaval Patel
11. 1. Radio Frequency Identification
• Operates in radio frequency band (3kHz to 300GHz)
• Automated identification
• RFID tags for each object to identify
• Categorising RFID tags based on [6]
• Source of power
• Passive
• Semi-Passive
• Active
• Power/data transfer
• Near-field
• Far-field
Waterproof RFID Wristband [5]
12. Based on Source of Power
Passive
• Power from RFID
reader
• No battery
• Short range
• Low cost
• Small in size
• Transmit when read
by an RFID reader
Semi-Passive
• Battery powered
• Long range
• Costly
• Larger in size
• Transmit when read
by an RFID reader
• Battery life around 5
year
Active
• Battery powered
• Long range
• Costly
• Larger size
• Transmit
automatically and
when read by an RFID
reader
• Battery life around 5
year
13. Based on Power/Data Transfer
Near-field RFID
Power transferred using magnetic
induction
Data transferred by varying current
using load modulation
Range is approximately: 푐/2휋푓
Used at frequency < 100 MHz
c: speed of light
f: frequency of radio wave
Figure: Near-field power/communication mechanism [6]
14. Based on Power/Data Transfer
Far-field RFID
Power transferred using
electromagnetic wave capture
Reflects received signal to transfer
data by varying antenna’s
impedance
Energy received is proportional to
1/푟4
Range is 3 to 6 meters
Used at UHF (Ultra High Frequency)
Figure: Far-field power/communication mechanism [6]
15. Effects of RFID Frequency
Factor Lower Frequency Higher Frequency
Read range (affected by energy
Short (in centimeters) Long (in meters)
contained in radio wave)
Interference (from Radio reflective
materials, like beverages, metals)
Less More
Data transfer rate Less High
Cost High Low
16. Effects of RFID Frequency
Frequency
Passive Active
Range Cost Range Cost
125-134.3 kHz Low Frequency (LF) 10 cm – 30 cm $1
13.56 MHz High Frequency (HF) 10 cm – 1.5 m $5
865-867 MHz Ultra High Frequency
(UHF)
1 m – 15 m $0.15 50 m $20
2.45 or 5.8 GHz Microwave 3 m 30 m $25
3.1–10 GHz Ultra Wide Band NA up to 200 m $5
17. Ultra-Wideband (UWB) RFID
• Operates in 3.1 – 10 GHz band
• Low power signals on a large range of frequencies instead of a strong
signal on a particular frequency
• Energy efficient
• Battery powered
• Long read range
• Less interference
• Cheaper than Active UHF RFID tags
18. 2. Near Field Communication (NFC)
• Available on high-end smartphones
• Operating frequency: 13.56 MHz
• Data transfer rate: 30 to 60 kbps
• Compatible with High Frequency RFID tags
• Can read/write HF RFID tags
• Short range
• Theoretical: 20 cm
• Practical: 5cm
Figure: Two NFC devices [7]
• Large amount of data can be transferred by paring up Bluetooth or Wi-Fi
• NFC chip can be read even if device is switched off
20. 3. Wi-Fi
• Operates in 2.4GHz and 5GHz bands.
• Long range (20m to 300m)
• High data transfer rate
• Tracking smartphones using Wi-Fi
• Periodic transmission of probe messages
• Each frame contains MAC address in plain-text
• Techniques
• Passive
• Active
21. Passive Wi-Fi Tracking
• No transmission of frames by Wi-Fi monitor
• Silently listen to all the frames transmitted by others
• Problems
• No control over the transmission time of frames
• No guarantee of frame transmission
• A corrupted frame might be dropped
• More number of frames can provide better accuracy
22. Active Wi-Fi Tracking
• Transmission of frames by Wi-Fi monitor to trick smartphone
• Goal is to increase the
• Number of devices detected
• Number of frames transmitted
• Techniques
• Advertising popular access point’s SSID
• Opportunistic access point emulation
• Sending RTS packets
23. Advertising Popular Access Point’s SSID
• Smartphones automatically try to connect to known AP
• Broadcast beacons containing SSID of popular AP
• E.g. “attwifi”, “tmobile”
• No need of fully functional AP
• Get more frames
• Emulate fully functional AP
• Null frames for notifying power state
24. Opportunistic Access Point Emulation
• Directed probe request for known networks
• Contains SSID of the access point, along with other parameters
• Emulate access point with that SSID
• Security protocol must match for secured networks
• Security protocol information is not available in probe request
Search
•Probe
request for
SSID “A”
Emulate
•Emulate AP
with SSID “A”
Associate
•Association
request for
SSID “A”
Wait
•Null frames
transmission
25. Opportunistic Access Point Emulation
• Emulate multiple security protocols
• 4-way handshake required for secure
protocols
• Requires credentials
• No need to complete handshake
• Null frames transmitted until we
complete handshake for around 10
seconds
• After that the process is repeated
27. Sending RTS Frames to Known Devices
• No emulation of access points
• Transmit RTS (request to send) frame to a device
• In response we get CTS (clear to send) frame
• CTS doesn’t have transmitter address (TA), only
receiver address (RA)
• Set TA to a unique address (UA) in each RTS
RTS
(UA, RA)
CTS
(UA)
29. 4. Bluetooth
• Operates in 2.4 GHz band
• Energy efficient (2.5 mW for class 2 devices)
• Long range (10m to 30m)
• Decent data transfer speed
• Tracking methods
• Inquiry based
• Inquiry free
30. Inquiry Based Tracking
• Transmit discovery packet on predefined 32 channels
• Discoverable devices respond to this packet
• Response follows a random delay to minimize collisions
• Takes around 10 seconds for all devices to respond
• Problems
• Requires a device to be discoverable
• Privacy risk
• Disrupts normal communication whilst scanning a channel
31. Inquiry Free Tracking
• Connection based approach
• Requires paring up with Bluetooth monitor
• Send inquiry targeted for a particular device
• Requires multiple inquiry messages
• Faster targeted discovery
• Maximum 7 simultaneous connections to other devices
32. 5. Global Positioning System (GPS)
• Provides position, velocity and time
• Position accuracy (outdoor): 2 to 10 meters
• Position accuracy (indoor): > 100m
• Global Navigation Satellite System (GLONASS)
• GPS + GLONASS
• Better accuracy
• Faster fix
• Assisted GPS (A-GPS)
• Gets the almanac and ephemeris data from the Internet
• Send the location to the central server
34. System Designs
• Scalable
• Should handle real-time location updates of millions of people
• Reliable
• Inter-operable and compatible with other systems
• Components
• Position data collection techniques
• Location Based Services (LBS)
• Finding nearby ATM
• Traffic information
• Geographic Information System (GIS)
35. 1. Smartphone + RFID
• Developed for Hajj
• RFID tag for each pilgrim
• App for smartphones with GPS
• Locating family members or friends
• Requesting urgent help
• Map of important locations
• Control center
• Visualizing location of all pilgrims on a map
• Searching for pilgrims based on region, age etc.
• Maintains database of hospitals, location history, personal information
37. Smartphone + RFID
• Problems
• Read range of RFID reader was low
• Affected by environmental factors
• Interference from human body
• Collocated tags
• Taking back wristband tags
• Conclusion
• Not to use wristband RFID tags
38. 2. Smartphone GPS [HajjLocator]
• Get location from GPS
• Send location using
• Wi-Fi
• 3G
• SMS (emergency)
• Update location after certain
• Time period
• Distance travelled
• Geo-fencing
• Searching for someone
• Push notifications
40. 3. Wireless Sensor Network (WSN)
• Developed for Hajj
• Need for tracking in addition to identification
• A sensor unit for each pilgrim
• Mobile sensor unit consists of
• GPS
• Microcontroller
• Antenna
• Battery
• ZigBee radio
• Fixed master units
• Get position data from mobile sensor units
• Send this data to central server by routing through other fixed units
41. Wireless Sensor Network
• Node configurations
• End nodes
• Routers
• Gateways
• Information packet
• UID number
• Latitude
• Longitude
• Time
• Searching for someone
• Routing multiple queries in parallel
• Based on previous known location
• Very high cost
• Comparable with smartphone
Figure: Node configurations [9]
42. 4. Bluetooth
• Networked host machines with Bluetooth class 2 devices
• Current position of all devices stored on central system
• Ask a host which is probably near to a device
• Frequent connection and disconnection
• Clock synchronization for faster connection time
• Distribute clock information to other hosts
• Can tolerate an error up to 10.24 seconds
• Average connection time after utilizing clock information: 0.64 seconds
43. 5. Wi-Fi Monitors
• Designed for tracking smartphones on a street for traffic flow and
congestion monitoring
• Wi-Fi monitor: standard AP with custom firmware
• MAC address + signal strength
• Monitors were 400 meters apart
• Mean error: 70m
• Problems
• A phone may pass a monitor without transmitting any frame and remain undetected.
• Techniques for increasing frame transmission
• Stationary devices
• Maintain blacklist
45. Summary
Technology Distance Power
consumed
Cost Remarks
RFID (Passive) < 3 m No battery Very Low Best suited for identification
RFID (Active) ~ 100 m Very Low Low Interference from human body
NFC ~ 4 cm No battery High Can read/write RFID tags
Bluetooth 10 m – 30 m Low High High availability in phones
Wi-Fi 20 m – 200 m High High Drains battery of smartphone
GPS +
Networking
Anywhere on
earth surface
High Very High Requires an app to be installed in
smartphone
46. Conclusion
• Passive UHF RFID tags are cost effective but their range is limited to 3
meters.
• UWB tags can provide long range but are more expensive.
• Using smartphone GPS is best for real-time tracking but require active
Internet connection.
• Bluetooth and Wi-Fi based methods are independent of OS of
smartphone and don’t require Internet connection.
• None of the system discussed address the issue of scalability.
• None of the methods are without drawbacks.
47. References
1. http://www.thewonderoflight.com/fiap-awards-2/b1-lost-child/
2. http://news.oneindia.in/feature/2011/sabarimala-stampede-deadly-accident-for-hindu-pilgrims.html
3. http://www.swadeshnews.com/latest/unprecedented-rains-unplanned-urbanisation-behind-jk-floods
4. http://indiatoday.intoday.in/technology/story/kashmir-floods-live-jammu-and-kashmir-rescue-motor-boats-vaishno-devi/1/381531.html
5. http://en.asiadcp.com/company/productinfo.php?pid=60658&upcid=10482&id=128214
6. R. Want, “An Introduction to RFID technology,” Pervasive Computing, IEEE, vol. 5, no. 1, pp. 25-33, 2006.
7. http://www.nokia.com/mea-en/support/product/c7-00/userguidance/?action=singleTopic&topic=GUID-0D70FE24-64A1-4DB9-A6D2-
2355C10847D9
8. A. Musa and J. Eriksson, “Tracking Unmodified Smartphones Using Wi-Fi Monitors,” in ACM Conference on Embedded Networked Sensor Systems
(SenSys), 2012.
9. M. Mohandes, M. A. Haleem, A. Abul-Hussain and K. Balakrishnan, “Pilgrims Tracking Using Wireless Sensor Network,” in International Conference
on Advanced Information Networking and Applications (WAINA), Biopolis, 2011.
10. R. O. Mitchell, H. Rashid, F. Dawood and A. AlKhalidi, “Hajj Crowd Management and Navigation System,” in International Conference on Computer
Applications in Technology (ICCAT), 2013.
11. http://www.libelium.com/meshlium-scanner-smartphone-detection-improved-iphone-android-devices-mobiles-cellulars-bluetooth-wifi/
12. T. Mantoro, A. D. Jaafar, M. F. M. Aris and M. A. Ayu, “HajjLocator: A Hajj Pilgrimage Tracking Framework in Crowded Ubiquitous Environment,” in
International Conference on Multimedia Computing and Systems (ICMCS), 2011.