Location-based Services (LBSs) are IT services for providing information that has been created, compiled, selected, or filtered taking into consideration the current locations of the users or those of other persons or mobile objects.
M-commerce: Mobile Commerce
Location Based Services
Friends & Family
Aim and Objectives
Privacy of LBS
Comparison of Positioning Systems
Conclusion and Future Work
• To evaluate a Location Based Services (LBS) positioning techniques.
To investigate the characteristic of the LBS.
Gaining an understanding of components of LBS and underlying technologies.
To study the existing LBS systems.
Investigating the challenge of protecting the privacy of LBS users
To comparing between the LBS systems.
Three important standards (OpenLS, GML and KML)
The Open Location Services (OpenLS) standard proposes an overall
system architecture for various components :
location collection services .
LBS application providers .
Geography Markup Language (GML): This is an XML-based language
for representing various geography data such as points of interest.
Keyhole Markup Language (KML): This complements GML by providing
information about annotations and markings on maps (visualization).
Why privacy is a concern with LBS ?
Identification Requirements of LBS .
Transformation of Location request data.
• Cell of Origin (COO): This technique is used if the positioning system has a
• Time of Arrival (TOA): Time Difference of Arrival (TDOA).
• Angle of Arrival (AOA): If we use antennas with direction characteristics.
Triangulation:: needs two fixed positions (p1 and p2). , we measure the angle
to the location u.
Trilateration:: also needs two fixed positions, but uses two distances to the
Traversing: uses several distance–angle pairs. We start with a known point p1
and measure the bdistance and direction
(Global Positioning System )
(Radio Frequency Identification )
Infrared , RFID & WLAN
(Wireless Local Area Network
(Global System for Mobile)
• Cover huge geographical areas.
• Standalone infrastructure and terminal-based
Positioning requires line-of-sight between satellite and receiver
High power consumption at the receiver
High operation costs
GPS (Global Positioning System)
Principle of satellite positioning.
The user knows the distance of the satellite
to him, as well as the position of the
So he can calculate a radius is
somewhere on. But he does not know
where on the radius he is.
By looking at the intersection of the coverage radius of
at least 3 satellites, he can discover his exact position
Focuses on positioning services within the coverage area of a cellular network.
• Good yield (in most cases even indoors).
• Some positioning methods require either no or only minor modifications at mobile
devices (firmware upgrade).
High signaling overhead.
Enhanced Observed Time Difference (E-OTD).
Assisted GPS (A-GPS).
Deployment in buildings, university campuses, and company premises
Stand-alone and integrated infrastructures (e.g., RFID vs. WLAN)
Low power consumption
Proprietary systems, i.e., no standardization
Position can be detected by measuring Signal Strength of all wireless LAN access
Wi-Fi: Wireless Fidelity
Depends on Cell
Dependent on WiFi AP density 3 m
Many LBS applications use GPS to determine the current location.
however: It only works outdoors because the receiver must have a direct view
to at least four GPS satellites.
no positioning system is accessible everywhere.
If a service wants to have high coverage, it has to rely on several positioning
More investigations are required to assess the behavior of the LBS under
different positioning techniques.
To explore the limitations of the LBS paradigm .
To develop real LBS systems which are more intelligent and accurate.
More investigations are required to assess user experiences in regard to
privacy and security.
 L. Perusco and K. Michael, "Control, Trust, and Security: Evaluating Location-Based Services", IEEE Technology
and Society Fvlagazine, Spring 2007
 M. Takeda, "Will GPS Mobile Phones Become the Driving Force in the GPS Applications Market?", nG Mobile in
Japan and Asia, 1(7), July 22, 2002.
 J. Green, D. Betti, and J. Davison. Mobile Location Services: Market Strategies, OVUM, London, 2000.
 G. Alonso, F. Casati, H. Kuno, and V. Machiraju. Web Services: Concepts, Architectures and Applications. Springer
Verlag Publishers, Berlin/Heidelberg, 2003.
 I. Burcea, H.-A. Jacobsen, E. DeLara, V. Muthusam, and M. Petrovic. "Disconnected Operations in
Publish/Subscribe." IEEE Mobile Data Management, IEE Publication, pages 39–50, 2004.
 H.-A. Jacobsen. "Middleware Services for Selective and Location-based Information Dissemination in Mobile
Wireless Networks." Advanced Topic Workshop on Middleware for Mobile Computing, November 12–16, 2001.
 K. V. B. Andersen, M. Cheng, R. Klitgaard-Nielsen. "Online Aalborg Guide: Development of a Location-Based
Service." Student Report, 102 pages, Aalborg University, 2003.
 K. Dueker and J. A. Butler. "GIS-T Enterprise Data Model with Suggested Implementation Choices," Journal of the
Urban and Regional Information Systems Association, 10(1):12–36, 1998.