Location Based Services in Telecommunication Networks

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Copyright to Rohana K Amarakoon @ http://uncopyrightables2011.blogspot.com/

1876 Telephone
1980 FAX
1995 Internet
1999 e-Everything
2000 m – GIS and LBS
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Past
Most of this income is coming from Short Message Services
(SMS)
Later
MMS, IM, email and mobile Internet (Wireless Application
Protocol [WAP])
Now
Tracking user & applications. (LBS Services)
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services that integrate a mobile device’s location or position with
other information so as to provide added value to a user.
Location Based Services (LBS)
In 1970s, the U.S. Department of Defense has been operating the global positioning
System (GPS), a satellite infrastructure serving the positioning of people and objects.
In 1980s, U.S. government decided in to make the system’s positioning data freely
available to other industries worldwide.
History
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Definitions
Definition 1 :
LBSs are information services accessible with mobile devices through the
mobile network and utilizing the ability to make use of the location of the
mobile device. (Virrantaus 2001)
Definition 2 :
A wireless-IP service that uses geographic information to serve a mobile
user. Any application service that exploits the position of a mobile
terminal. (Open Geospatial Consortium (OGC, 2005))
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Military & Government Industries
Emergency Services
Commercial Sector
Air traffic control
Sea port control
In-car navigation
Freight management
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A two way communication and interaction
User : tells the information he needs, preferences and position
Provider : deliver information tailored to the user needs
Provider to answer :
Where am I ?
What is near by ?
How Can I go to ?
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GPS (NAVSTAR)
Galileo
GLONASS
Types of Satellites provides LBS
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1980 1990 2000 2005
MarketSize
$1 Billion
$5 Billion
$10 Billion
GIS Market
Internet and Mobile
Location Services Market
Inflection
Point
Time
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Person Oriented (ex : friend finder application)
Device Oriented
Major Classification
Cell phone Palm top
Lap-top Kiosk
Car-based computer Cell antenna
Mobile device Display
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Push Services
Pull Services
Other Classification
The information may be sent to the user with prior consent or without prior
consent
User actively uses an application and, in this context, ‘‘pulls’’ information from
the network
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Perception of being observed.
Location based spam messages.
Unsolicited messages pushed to mobile phones (may be perceived as
even more harmful than email spamming)
European Union Policy (Directive 2002/58/EC)
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Positioning Layer : Responsible for calculating positions of device or user.
Application Layer : offer the services requested by applications.
Middleware Layer : Reduce the complexity of service integration.
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Location middleware can be used to manage interoperability between networks
for location date. 25

Digital Maps
Point of interest information
Data Capture & Collection
Dynamic Data
Concierge application use business and landmark info
Point of Interest Information (POI)
POI Data collected from multiple vendors merge in to single DB
Each record in POI DB is geo coded
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Dynamic data capabilities server LBS engines because they
allow dispatches to react almost instantaneously to changing
conditions
Dynamic Data
Geo coding & reverse geo coding
Location Engine
Routing
Proximity searches
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Standard based tool set need API that adhere to industry
standards such as C, Java, XML.
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Future mobile devices will be used more frequently to access dynamic and
personal geo-relevant content.
LBS technology and applications will be key driver of the mobile service market.
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Navigation systems guide objects moving from one place to another have progressed
recently with the rapid advances in positioning, communication, and spatial data
storage and processing technologies.
The easy availability of satellite-based global positioning systems has revolutionized all
forms of automated navigation :
LBS provide the ability to find the geographical location of a mobile device and
then provide services based on that location.
LBS application services provide the ability to find the geographical location of a
mobile device and then provide services based on that location.
The core services are location utilities services, directory services, presentation
service, gateway service, and route determination service.
The Spatial DB act as a backend server to the geo mobility server.
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Integrated collection of position and orientation sensors and computing and
communication H/W and S/W.
Navigation systems cover a broad spectrum of integrated technologies that allow
accurate determination of the geographic coordinates of the (moving) objects,
their velocity, and height.
LBS uses accurate and real-time positioning systems and GIS to determine the
location of a moving object.
The OGC recently initiated the OpenLS standard to address the technical
specifications for LBS.
The core of LBS applications is the back-end SDB server, which provides efficient
storage, management, and processing capabilities for geospatial data.
The SDB server provides dynamic information on demand to aid automated
navigation.
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Essential component for building efficient navigation system application.
Conceptual Data Model
Logical Data Model
Physical Data Model
It acts as a back-end SDB server to the GeoMobility server.
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Open Location Server is to produce open specification, for interoperable location
application services that will integrate spatial data and internet services
infrastructure.
Geo Mobility Server provide deliver and service location based applications.
Location Utility Services
- Geo Coding
- Reverse Geo Coding
Directory Service (Point of location - Interest)
Presentation Service (Visualize the spatial data)
Gateway Service ( Obtain position of mobile terminal from the N/W)
Route Determination Service
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Data Quality should be high. ( relative accuracy and precision of a particular GIS DB.
Lineage
Narrative of sources materials used and procedures applied for produce the
product.
Position Accuracy
Defines expected error in position of features.
Attribute Accuracy
Completeness
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High level conceptual data model
Logical modeling (related to the actual implementation of conceptual data
model)
Physical design (implementation of the db applications)
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Interface between the Open Location Services Platform and Mobile Positioning Servers
through which the platform obtains near real-time position data for mobile terminals.
Stand-Alone positioning system
‘‘current position’’ with reference to a ‘‘starting position”, direction mapped
from start point (speed and direction calculate)
Satellite based positioning system (NAVSTAR)
using 3 parts this will provide the service.
Space segment (satellite)
User segment (GPS receiver)
Control segment (Monitoring stations)
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Terrestrial ( Radio based positioning system)
Systems are designed for specific applications (e.g., offshore navigation) and
are generally managed by government and military/naval agencies.
Terrestrial positioning systems commonly;
Employ direction or angle of arrival (AOA)
Absolute timing or time of arrival (TOA)
Differential time of arrival (TDOA)
techniques to determine the position of a vehicle.
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Geo Coding
Assigning an latitude and longitude coordinates to a given address.
Reverse Geo Coding
Find the address through the latitude and longitude coordinates.
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LBS provides a search capacity for one or more Points of Interests (POI)
A POI is a place, product or service with a fixed position, identified by name.
Point Query (PQ)
Range Query (RQ)
Nearest Neighbor Query (NNQ – use KNN algorithm)
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This address finding route and navigation between locations.
New Routes
Alternative Routes
Path Query Processing
Determining shortest path between two locations.
Dijkstra’s algorithm, IDA, SMA & Best first A* algorithm used here.
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Currently, most presentation services are provided, based on visual interfaces
framework. In future audio guidance along with visual.
Centralized Model
Traveler communicates with a management counter, which traces the traveler
location, speed and other info.
It is the management center’s responsibility to compute the route and broadcast
this info to the traveler.
Distributed Model
Route computation is performed by the guidance unit at the hand of the traveler,
those need high computational ability.
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Middleware consists of set of services
Exposing interfaces
Programming model
Interaction model ( to the application developer)
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LBS broken-down in to
B2C
B2B
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Infotainment services ( Finder apps & information request apps – pull based info)
Tracking services (Supply chain & inventory, vehicle & people tracking – push &
pull info)
Selective info dissemination (Targeted content dissemination – push based info)
Location based games
Emergency support service (119, Ambulance, Fire brigade - need middleware)
Location sensitive billing ( call billing, toll payment, purchase good and services –
no special middleware support)
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Push and Pull Based Applications
Push – request are initiated by the mobile terminal
Pull - infrastructure autonomously and proactively pushes info to mobile
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Push and Pull Based Applications
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Direct vs Indirect Profile
Personalized application correlates a services request with requester profile
information.
Direct – gather info from user
Indirect – gather info from third parties
Availability of profile information
Profile info can be available always or on specific time in the LBS
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Interaction Scenarios
The interacting entities, mobile terminals and LBS more generally speaking, service
requester and service provider can be either mobile or stationary.
Both requester and provider are stationary. Conventional info services are good
example for this category.
Either be requester or provider are mobile and stationary, respectively their
interpolation and instantiation depends on how the application is modeled.
Both requester and provider are mobile, LBS take on the role of coordinator.
Source of Location Information
Queried by LBS application or be transmitted by the mobile terminal.
Accuracy of Location information ( This model depends on the infrastructure)
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LBS middleware platform do :
Manage the mobility inherent to all LBS applications by supporting disconnected
operations and supporting mobility awareness in the middleware.
Manage changes in the underlying N/W topology.
Manage millions of info of both consumers and subscriptions.
Manage potentially very large no of information providers.
Manage highly volatility of users interests.
Perform accounting and securing functions.
Support privacy consideration, allowing subscribers to opt for the propagation if
their location info to selected applications only.
Support high rate of inputs (NEWS, location info per user) 53

Set of services that facilitates the development and deployment of distributed
applications in heterogeneous environments.
The objective of a middleware system are to abstract details of the underlying O/S,
N/W and protocols
Standard API give rise to application portability and system interoperability
LBS middleware is more specialized. It aims at facilitating the deployment and
development of LBS applications in heterogeneous N/W environments
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LBS middleware is deployed within the N/W operator’s H/W or hosted by an application
service provider:
Connects Consumers on;
Mobile terminals & internet
3rd party application providers
N/W operators to offers single location based application portal
Integrates with;
N/W infrastructure (location services, WAP gateways, subscription portal
services)
Customer care, customer activation services
Billing systems, accounting systems 55

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Publish / Subscribe
These apps organized as a collection of co-operating components, consisting of
producers, which interact by publicizing events and consumers, which subscribe to
specific events they are interested in.
Two Dimensions:
Expressiveness of the data model (subscription language and publication
model)
Architecture of the event broker
The public / subscribe middleware model is inherently,
Asynchronous Anonymous (no need to know
clients)
Multipoint (many clients) Implicit & Stateless
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Publish / Subscribe paradigm is well suited for modeling selective information
dissemination tasks.
Publish/subscribe system model to support location-based services
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Subject Spaces
Is a generic system model to express asynchronous interactions of
decoupled entities.
It is similar to public (subscriber style interactions)
The objective of subject space is to provide a precise of the behavior of
publish / subscribe systems
Subject spaces are used for categorizing publication and subscriptions.
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Tuple Spaces
This model’s primary strength is it’s ability to coordinate many concurrent
activities, including the stateful interaction among multiple activities.
Tuples are typed data elements, designated as actuals, if the contain data
values, and as formals.
Tuples can be dynamically inserted, read and removed from the tuple
space, but they can’t altered while in the space.
update and changes to tuples can be done, first removing the tuple from
he space, update it and insert back.
All communication is performed via the tuple space, also referred as
generative communication
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Tuple Spaces Operations
out (t):
Insert tuple in to tuple space
in (t):
Extracts a tuple matching tuple template t from the tuple space
rd (t):
equivalent to in(t) , expected than matching tuple is copied and not
removed from the tuple space
eval(..):
Generate active tuples that turn into (passive) tuples, as the associated
computations terminate
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Tuple Spaces Operations
In the location based application, information producer and information consumer
interact via a space by inserting and extracting tuples.
The tuple space decouples the communication between the producer and the
consumer.
DMBS Based Model
This model supports a pull style interaction scheme.
A mobile terminal initiated request is evaluated on a database and any results are
returned to the requester.
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The delivery of LBS in practice depends on the existence of a well following value
chain. At a value chain begins with content providers.
Weather data
Traffic data
The content integrator manages content received from multiple sources. It maintain a
db and IT infrastructure that are capable of capturing the content received.
The db making the content available to LBS offered by multiple service providers.
Types of content
Geographic Infrastructure
Other real data (POI data)
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All the real content, also turned business data, encompasses any content that may
reference, directly or in directly the geographic infrastructure.
Special-purpose geographic information system (GIS) software
manages the geo content
general-purpose relational database management system (RDBMS)
manages the real content
In LBS, the special-purpose GIS world and the general-purpose relational data
management world need to be integrated.
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Several data management challenges exist in relation to LBS.
Modeling Update Content
Representation of Content Querying of Content
Content in static is problematic, dynamic content designed to accommodate updates.
Content is more or less dynamic.
Representation of Infrastructure.
Content capture
Content representation, update and querying
Display
Representation integration 66

Multiple external infrastructure representations.
Road centric representation
Graph representation
Geo representation
Internal Infrastructure Representation
Competing the other external representations to this representation.
Internal representation uses three tables.
Element (Element ID)
Connections (Connection ID)
Element connections (Element ID) 67

Kilometer post representation
Road table and kilometer post table used for this.
Graph representation
Road N/W is an abstraction. Node table and link table used for this.
Geo references
Summary of infrastructure representation
Content modeling
Modeling different aspects of infrastructure,
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Content modeling
Elements are related to everything else, so is the content.
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Updates could be performed efficiently, preliminary by ensuring that the same data
are not represented multiple times.
Update caused by discrete change
Many updates would be needed if the social secure no were used as primary key.
Update caused by continuous change.
Movement by linear function
User movement
infrastructure representation
Client side caching
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Update caused by continuous change.
Position Tracking
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Fundamental technique for modeling transportation infrastructure.
Linear referencing concepts
Linear elements
Any geometric shape feature that can be given a meaningful start point
Events – points and linear
Linear referencing method
How location along or beside a linear elements is measured.
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Linear referencing in oracle
Line string (continuous geometry)
Multiline string (unconnected line string)
Polygon (line string which has starts and ends at the same point)
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Information and communication technology standards are critically important to the
commercial rollout of LBS and fulfillment of their potential.
Standards are important to LBS users.
Individuals and corporate customers are new beginning to purchase,
location based emergency services
location based advertising
location based games
location responsive instant messaging systems
LBS to be integrated in to their current billing as just another set of phone charges.
Standard are important to LBS providers
“Billing one and selling it many times.”
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When we use location services, we are depending on technologies that can do
following.
Provide us with wireless communications
Provide us with determination
Store, serve and apply geo referenced (location, related) data in response to
queries.
Standards are important in LBS for the same reason they are important in other
markets. They help,
Providers deliver usable products
Services while saving time
Money and reducing business risk
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LBS standards benefits providers in the LBS value chain by enabling the following
Increased billable utilization of carrier’s spectrum and wireless network.
Niches for providers with special products and services.
A business case for different content providers.
Expansion of LBS from a niche service to a mass market service.
These standards will be the road map for the definition of an industry and its customer
driven deployment of mass market services and content by carriers and internet service
suppliers like AOL or Microsoft.
Because of several technologies and industries are involved, the standards picture is
more complex.
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Open mobile alliance (OMA)
Open GIS consortium (OGC)
Location interoperability forum (LIF)
Year 2000 – Motorola, Ericson and Nokia started this, purpose is to developing and
promoting industrial common solution for LBS
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LIF’s mobile location protocol (MLP) enables location applications to interoperate with
the wireless N/W’s
MLP supports privacy and authentication that user’s whereabouts are protected.
WAP is also a part of OMA, which provide wireless internet standards, communication.
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Developed by OGC
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Organizations which provide standards
Cellular Telecommunications & Internet Association (CTIA)
Third Generation Partnership Project2 (3GPP2)
Automotive Multimedia Interface Consortium (AMIC)
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OGC members have cooperatively developed the Geomobility server (GMS)
Open interfaces for LBS middleware (OGC2)
Mobility
Mobile Devices
Mobile S/W components
Interoperability of geomobility enables LBS platform providers and content providers to
provide their S/W and data to multiple carriers.
The geomobility server is an open service platform comprising the core services
developed under the OGC OpenLS initiatives.
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The goal is to enable communication of location, route, type of service.
The primary objective of OpenLS is to define access to the core services and abstract
data types (ADT) that comprise the geomobility server.
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Geo mobility server provides open interfaces to core services for LBS
Route determination
Determine the route and navigation information between location
Location utility
Geocoder and reverse geocoder
Presentation
Showing map, route, POI and route instructions
Gateway
Get position from the mobile terminal
Directory services ( search of POI) 85

Route
Metadata pertaining to a route
Route instruction List
Provides turn by turn navigation instructions
Location
Position
Area of interest
Point of interest
Address
Map
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Satellite Positioning System
Indoor Positioning System
Networked Based Positioning System
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Location based services must be able to detect the location of a mobile user.
Introduction
satellite based positioning system such as GPS achieve high coverage and
precision, but they fail indoor environment.
position is an important function for many areas like ,
- land surveying
- aviation
- aeronautic
- robotic
- virual / augmented reality
positioning system for LBS used to provide considerable coverage and to allow
the location of mobile users with small mobile devices or badges.
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Coordinate System
that describe a 3D worldwide unique location can be divided into two classes:
LLA
- Latitude
- Longitude
- Altitude
ECEF
- Earth Centered
- Earth Fixed - zero point of gravity
These are serve as reference frames for coordinate systems. Famous model is WGS 84
(world geodetic survey 1984)
Scope
A positioning system has a certain scope and defines an area of potential
coordinates.
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Coverage
The actual coverage of a location system may be smaller than the area of potential
locations specified by the scope
Precision
Users and services that access location data must be aware of inaccuracy.
Geographic vs Semantic Locations
Users of the LBS interested in meaning of the location instead of coordinates.
Semantic location rather than a powerful representation for a great amount of LBS.
Additional Spatial Data
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Determine the location of mobile user
Tracking
Positioning (mobile system determine the location)
Tracking and positioning are based on the following techniques,
Cell of the origin (COO)
positioning system has a cellular structure, wireless transmitting use for this.
Time of Arrival (TOA)
Time difference of arrival (TDOA) – (electromagnetic signal used)
Angle of Arrival (AOA)
Measuring the signal strength
Processing video data
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Advantages
Positioning can in principle be carried out everywhere on the earth.
Environmental conditions, such as the weather, have only minimal influence
on the positioning process.
A high precision is obtained.
Disadvantages
Considerable costs arise for launching and supervising the satellites.
The positioning only works if the user receives a sufficient number of satellites
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Basic principles
We need at least three satellites to determine the user’s location in three
dimensions.
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GPS (NAVSTAR-GPS)
Started in 1970s, Navigation systems with timing and ranging – Global Positioning
System.
Department of Defense (DOD)
Department of Transportation (DOT)
National Aeronautics and Apace Administration (NASA)
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GPS segments
User Segment
Contains the devices of the mobile users. GPS receivers can be plug in cards or
separate devices can be plug in cards separate devices with a several interface
connections.
Space Segment (consists of the satellites)
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GPS segments
Control Segment
Administration of the satellites as well as for correction of the satellites
internal data.
24 satellites move on 6 orbits with 4 satellites per orbit. Satellite need 12
hours for complete a complete orbit.
For the usage user don’t need to register and it is free of charge.
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GPS services
Precise Positioning Service (PPS)
Military purpose (22m x 27.7m square for 24 hours)
Standard Positioning Service (SPS)
General usage (100m x 156m for 24 hours)
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Distortion for GPS services
Clock errors.
Although the clocks in the satellites work exactly, clocks cause an error of
1.5m in the position calculation.
Fluctuations of the orbits. (error of 2.5 m)
Disturbances of the atmosphere. (error of 0.5 m)
Disturbances of the ionosphere. (error of 5 m)
Multipath error. (error of 0.6 m)
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DGPS and WAAS
DGPS
(Differential GPS – error corrections)
WAAS
(Wide Area Augmented System)
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Satellite signals cannot use for
positioning in buildings.
Because signals can’t penetrate
solid walls.
So indoor positioning technologies.
Infrared beacon
Radio beacon (RFID)
Ultrasound system
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Video Based System
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GPS is really costly. To reduce cost, existing wireless N/W can be need for
positioning services, using cell ID of BST we can do this.
TOA and AOA also help to delimitation of the position.
GSM
Each phone has registered SIM.
Which contain info about user and store them in VRL (Visitor Location
Register)
When user info passed to central DB called HLR (Home Location Register)
Each cell phone operator has HLR.
City Range 1Km , Countryside Range – 35Km
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Erricson developed a system called MPS (Mobile Positioning System) which makes
more exact positioning possible in large cells
The mobile participant can query for location dependent data
(Ex: restaurants)
Users can supervise the location of other mobile users.
Route planning can be done.
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To compute the positions, MPS use.
Cell of Global Identity (CGI)
Use the identification of a cell roughly, determine the position.
Segment Antennas
Base station often have antennas, which divide the 360 in o segments.
Timing Advance
BST and mobile terminals use certain time slots for communication
Uplink Time of Arrival (UL-TOA)
by measuring the signal runtimes from a mobile terminal to the base station,
the position can be determine with a precision of 50m to 150m.
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On top of the transmission, mobile communication system can be constructed in
many different ways, serving many different purposes.
LBS can be built on top of many different system architectures.
Choice of Transmission Medium
Connection between two communicating peers
Availability of Infrastructure
Wireless communication does have limited range, But mobile communication need long
range communication.
Infrastructure Based Systems
Ad-hoc Multihop System
Hybrid System
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Infrastructure Based Systems
To overcome wireless communication limited range issues, wired Infrastructure
introduced.
Each BST cover a certain Area, for each terminal In this area, the base station Ensure
that data can be, Transmitted.
Structure of a cellular, infrastructure based
communication system
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Ad-Hoc or Multihop System
In have terminals are not all in mutual communication range of each other.
So middle can act as a relayer of each other. For data coming from one terminal and
forward the message towards its destination.
Message travels several radiohops.
A common characteristic of both single and multiple ad-hoc N/W is the need to be self
oriented in setting up and maintaining the N/W.
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Hybrid System
Infrastructure based and a-hoc multihop N/W can be combined.
Adding such multihop communication to cellular N/W is powerful way to widen the
coverage area of base station or increase the capacity of single cell.
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GSM – (Global system for mobile communication)
UMTS – (Universal mobile telecommunication system)
WLAN – (Wireless local area networks)
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Wireless communication has two essential problems to solve.
How to communicate data between a source and a destination.
How to organize multiple sources that want to send at the same time.
Wireless communication between a single sender and receiver
112

Mobile communication use 800 MHz to 5 GHz range
There are legal restrictions and reservation for other applications too (Digital radio or
television broadcasting)
900 – 1800 MHz are used for large scale, outdoor communication systems.
2.4 – 5 GHz used for medium and short range communication systems.
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Mobile communication should provide full coverage.
The phone calls should have the quality of fixed network calls, necessitating good
quality of service support.
First Generation
Analog mobile communication systems did not meet all of the above
requirements
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Second Generation
GSM N/W architectural overview
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Between generations – GSM Extensions
High Speed Circuit Switched Data (HSCSD)
Easily enables higher data rates by bundling several modern connections in single logical
connection
Enhanced data raes for GSM Evolution (EDGE)
General Packed Radio Service (GPRS)
This overcome the circuit switched communication. This used packet switching
technology.
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Third Generation – UMTS
Tight integration of traditional voice and data applications.
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Internet is the second largest communication in the world
118

IEEE 802.11 – WLAN Family
802.11a – orthogonal frequency division multiplexing
802.11b – direct sequence spread spectrum
Internet Based Mobile Communication
In a N/W based on the internet protocol suite, a terminal is identified by its IP address.
Ad-Hoc Networking
Use multi-hop communication
Location Based Service Discovery
Ex :- WIFI enabled laptop might want to get a printout which close by printer which also
WIFI enabled
119

Problems of LBS Discovery
Request for services are flooded through the entire network
When the network size grows, flooding becomes unattractive
In some type of networks having an identifiable service discovery node can be
undesirable
120

For more information
E-mail :
rohana.blogs@gmail.com
Blog :
http://uncopyrightables2011.blogspot.com/
Twitter :
@MaxRohana
121

Location Based Services in Telecommunication Networks

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