The document discusses the application layer of WAP including the WAP model, mobile location based services, WAP gateway, WAP protocols, WAP user agent profile, caching model, wireless bearers of WAP, WML, WML scripts, WTA, iMode, and SyncML. It provides definitions and details on the WAP architecture, protocols, and technologies to enable wireless internet access from mobile devices. The document also covers mobile location based services and applications, challenges, and examples of location based services that utilize a user's real-time geographical position.

1. Application Layer
By,
C.Janani AP / IT,
SSMCE

2. Topics
• WAP Model
• Mobile Location Based Services
• WAP Gateway
• WAP Protocol
• WAP User Agent Profile
• Caching Model
• Wireless bearers of WAP
• WML
• WML scripts
• WTA
• iMode
• SyncML

3. 1. WAP Model
• An international standard establishing how
mobile devices can access information on the
Internet.
• Providing Internet communications and
advanced telephony services on digital mobile
phones, pagers, personal digital assistants, and
other wireless terminals - WAP Forum

4. Definition
• Wireless: Lacking or not requiring a wire or wires pertaining to
radio transmission.
• Application: A computer program or piece of computer software
that is designed to do a specific task.
• Protocol: A set of technical rules about how information should be
transmitted and received using computers.
 June 26, 1997, Ericsson, Motorola, Nokia, and Unwired Planet took
the initiative to start a rapid creation of a standard for making
advanced services within the wireless domain a reality.
 In December 1997, WAP Forum was formally created and after the
release of the WAP 1.0 specifications in April 1998, WAP Forum
membership was opened to all.

5. Need for WAP
• Open and secure and well suited for many
different applications including, but not limited
to stock market information, weather forecasts,
enterprise data, and games.

6. Benefits
• Device Independent
• N/W Independent
• WML
• Optimizing the content and air link protocols
• No reduction of the end users

7. Architecture
• Internet Model

8. WAP Model

9. Working of WAP Model
• The user selects an option on their mobile device that has a URL with Wireless
Markup language (WML) content assigned to it.
• The phone sends the URL request via the phone network to a WAP gateway using
the binary encoded WAP protocol.
• The gateway translates this WAP request into a conventional HTTP request for
the specified URL and sends it on to the Internet.
• The appropriate Web server picks up the HTTP request.
• The server processes the request just as it would any other request. If the URL
refers to a static WML file, the server delivers it. If a CGI script is requested, it is
processed and the content returned as usual.
• The Web server adds the HTTP header to the WML content and returns it to the
gateway.
• The WAP gateway compiles the WML into binary form.
• The gateway then sends the WML response back to the phone.
• The phone receives the WML via the WAP protocol.
• The micro-browser processes the WML and displays the content on the screen.

10. WAP protocol

11. • Application Layer
Wireless Application Environment (WAE).
• Session Layer
Wireless Session Protocol (WSP).
• Transaction Layer
Wireless Transaction Protocol (WTP).
• Security Layer
Wireless Transport Layer Security (WTLS).
• Transport Layer
Wireless Datagram Protocol (WDP).

12. WAE
• WML- XML compliant mark-up language
• WMLScript - ECMAScript based scripting language
• WAP Push mechanism
• User Agent profiles
• WTA - WAP telephony services

13. WSP
• Provides shared state between client and server used
to optimize content transfer
• Provides semantics and mechanisms based on HTTP
1.1
• Supports compact encoding of headers
• Supports push functionality
• Supports capability negotiation

14. WTP
• Provides efficient, reliable data transfer based on
request/reply paradigm
• Supports selective-retransmission
• Supports segmentation and re-assembly
• Message oriented (not stream)
• Supports an Abort function
• Supports concatenation of PDUs

15. WAP Security
• Transport level security is WTLS, based on TLS.
Provides privacy, integrity, authentication
• End-to-end security mechanism defined at the
transport layer
• Application layer security provided via WMLScript
crypto library

16. WDP
• Provides a network and bearer independent interface
to higher layers
• Provides port level addressing
• Provides segmentation and reassembly
• For link layers that support IP, UDP is used as the
Wireless Datagram Protocol layer

17. WAP and Smart Cards
• WAP supports use of Smart Cards to enhance security
• Wireless Identity Module specification supports
performing security functions & storage of sensitive
data
• Smart Card Provisioning specification defines a file
structure for secure storage of provisioning data

18. WAP’s current status
• WAP Forum has 200+ members including
– 90% of world’s handset manufacturers
– Carriers with over 100 million subscribers
– Leading infrastructure providers, software developers &
content providers
• WAP v1.2 specification suite approved Dec 99
• Commercial services now widely deployed

19. Changing marketplace
• High speed 2.5G technologies - GPRS, EDGE
• 3G technologies being developed with data rates of
up to 2Mbps
• Multimedia capable devices being developed
• Demand for richer content - high quality graphics,
audio, video

20. WAP next generation
• WAP Architecture Convergence group working to
ensure WAP’s architecture converges with the IETF
and other protocols
• WPG reviewing the output from the IETF PILC
group with a goal of incorporating TCP into the WAP
stack
• WAP continually evolving to ensure compatibility
with emerging technologies

21. Mobile Location Based Services
Location Based Information Systems
• Systems that integrate advances in mobile phones, software
development platforms, databases, positioning technology,
Geographic Information Systems (GIS), and communications
• All combined make possible the creation of Location-Based
Information Systems (LBIS) and Location-Based Services (LBS)
– Promise to change the way we live
• 3.25 billion mobile phone users in 2007
– Half the world’s population
• LBS subscribers using GPS-enabled cell phones expected to grow
from 12 M in 2006 to 315 M in 2011
– 20 M from 500 K in North America

22. LBIS Challenges
• Many players and technologies involved, and many issues unsolved
– Databases, GIS systems, positioning, applications
• Erroneous and variable information
– Accuracy of GPS fixes depend on positioning system, user location,
weather conditions, interferences, etc.
• Cellular communication networks
– Wireless transmission problems, such as fading, interferences,
disconnections, low bandwidth, etc.
• Cell phones
– Very resource-constrained device in terms of processing power, storage,
and energy capabilities
• Operating systems and interoperability

23. Location-Based Services (LBS)
• An application that provides users with information based on
the geographical position of the mobile device
• Main difference from other applications/systems
– Availability of the user’s position in real-time
– This single difference makes a BIG difference
• Initial LBS systems were subscription-based
– Traffic congestion notifications based on roads selected
from a Web site
– Received congestion updates about I-75 when on travel in
NYC!

24. Types of LBS Applications
• LBS can be either Reactive (“pull”) or Proactive
(“push”)
• A Reactive LBS application is triggered by the user
who, based on his current location, queries the system
in search of information
• Many examples
– Finding restaurants or places of interest
– Obtaining directions
– Locating people
– Obtaining weather information
– Sending emergency notifications to police, insurance
companies, roadside assistance companies, etc.

25. • In Proactive LBS applications, on the other hand, queries or
actions are automatically generated by the LBIS once a
predefined set of conditions are met
• System needs to continuously know where you are and
evaluate the predefined conditions
• Many examples as well
– Geofencing, e.g., children outside predefined boundary
– Fleet management
– Real-time traffic congestion notifications
– Location-based advertisement
– Real-time friend finding
– Proximity-based actuation
– Travel assistant device for riding public transportation,
tourism, museum guided visits, etc

26. Location
• In LBIS and LBS applications everything is about
LOCATION
• Important to know about different players and
techniques used in the provision of location information
• A location provider may or may not be the same entity
providing the location-based service to the user
• According to who provides the location information,
the system can be categorized as network-based,
mobile-based, and location provider-based

27. Network-Based Location Provider

28. Mobile-Based Location Provider

29. Location Provider-Based

30. A Complete LBIS Tracking Example
• General real-time tracking application with visualization
– Tracking devices, people, etc.
• Uses the mobile-based location provider architecture
• Proactive LBS application consisting of the following
components:
– Positioning system
– Client device
– Transport network
– Main control station
– Servers
• Standard and free software and standard protocols as much
as possible

31. Hardware
• Positioning system
– GPS and Assisted GPS (A-GPS)
• Client device
– GPS-enabled cell phone or any device with GPS or embedded
positioning system
• Transport network
– Cellular network with data plan (GPRS or similar) or network
connectivity using Wi-Fi or any other IP-based networking technology
• Main control station
– PC connected to the system to control service and visualize data, e.g.,
set up geofence and Google maps
• Servers
– Database, GIS for geocoding and reverse geocoding, application server
for processing

32. Software
• Java platform
– Java SE for clients and Java ME for resource-constrained
devices
• Sun’s Glassfish as the application server
• Google ‘s Web Toolkit for visualization
– Google Maps and Google Earth
• Postgres, and object-oriented relational database
• PostGIS, Postgres’s add on to support geographic
objects
• Standard communication protocols
– HTTP, TCP, UDP

33. WAP User Agent Profile
• Fundamental user agent of the WAE
• WAE allows the integration of domain-specific user
agents with varying architectures and environments
• Existing Markup language contents designed for PC’s
with large displays ans large memory capacities
• WAP handset may not able to store and display the
received contents
• To resolve this UA profile also known as capability and
preference information (CPI) allows content generation

34. UA End to End Systems

35. Components
• Client device capable of requesting and rendering WAP
Content
• Wireless network employing WAP 1.1 or later protocols
• A WAP capable GW capable of translating WAP
requests into corresponding requests over the internet
and translating responses from the internet into
corresponding responses over the WAPs
• The internet and intranet using TCP / IP based protocols
and possibly having one or more protocol GWs and
HTPP / Web Proxies.
• A web server can generate request content.

36. Caching model
• A number of extensions and clarifications have
been specified to facilitate the operation of
HTTP/1.1 caching on limited function devices
• A time sensitive cached resource is set to
“must revalidate”
• Sesitive to Time Synchronization (Time of day
Clock)
• Security enhancements (Prefetching)

37. Wireless Beares of WAP
• Short Message Service (SMS)
• Circuit Switched Data (USSD)
• Unstructured Supplementary Services Data (USSD –
used over GSM)
• General Packet Radio Service (GPRS – used over
GSM and TDMA)

38. WML
• WML scripting language is used to design
applications that are sent over wireless devices such
as mobile phones
• WML is an application of XML, which is defined in a
document-type definition.
• WML pages are called decks
• They are constructed as a set of cards, related to each
other with links

39. Syntax
<?xml version="1.0"?>
<!DOCTYPE wml PUBLIC "-
//WAPFORUM//DTD WML 1.2//EN"
"http://www.wapforum.org/DTD/wml12.dtd">
<wml>
<card>
...
</card> ...
more cards...
</wml>

40. WML Commands

44. WML Script Components
• Operators
 Arithmetic Operators
 Comparison Operators
 Logical (or Relational) Operators
 Assignment Operators
 Conditional (or ternary) Operators

46. WML Scripts Standard Libraries
• lang: The Lang library provides functions related to the WMLScript language core.
Example Function: abs(),abort(), characterSet(),float(), isFloat(), isInt(), max(),
isMax(), min(), minInt(), maxInt(), parseFloat(), parseInt(), random(), seed()
• Float: The Float library contains functions that help us perform floating-point
arithmetic operations.
Example Function: sqrt(), round(), pow(), ceil(), floor(), int(), maxFloat(),
minFloat()
• Dialogs: The Dialogs library Contains the user interface functions.
Example Function: prompt(), confirm(), alert()

47. • String: The String library provides a number of functions that help us manipulate
strings.
Example Function: length(), charAt(), find(), replace(), trim(), compare(),
format(), isEmpty(), squeeze(), toString(), elementAt(), elements(), insertAt(),
removeAt(), replaceAt()
• URL: The URL library contains functions that help us manipulate URLs.
Example Function: getPath(), getReferer(), getHost(), getBase(), escapeString(),
isValid(), loadString(), resolve(), unescapeString(), getFragment()
• WMLBrowser: The WMLBrowser library provides a group of functions to control
the WML browser or to get information from it.
Example Function: go(), prev(), next(), getCurrentCard(), refresh(), getVar(),
setVar()

48. WML Scripts Comments
• Single-line comment: To add a single-line comment,
begin a line of text with the
// characters.
• Multi-line comment: To add a multi-line comment,
enclose the text within
/* and */.

49. Sample Program