Wireless Telephony Applications

7/21/2019 Wireless Telephony Applications

http://slidepdf.com/reader/full/wireless-telephony-applications 1/35

Wireless Telephony Applications

• In this unit defined the mobile Internet-wireless

communications and the wired internet• Today mobile network supports- call forwarding,

call waiting and call conferencing

• In this unit describes how WAP WirelessTelephony Applications (WTA) provide a bridge

between wireless telephony and data.



Overview of the WTA Architecture• WTA App. Are developed using Wireless

Markup Language(WML) and WML Script.

• The fig. Illustrates the end-to-end system fordelivering these applications.

• WTA server communicates with the WAPgateway to deliver and manage the telephonyservices

• On the client, WTA app. Requires the presenceof the WTA app. Framework-supports the real

time needs of telephony app. And optimize thelow bandwidth to distribute content to the mobileclient.



• Framework-three components

1. WTA user agent executes WTA app. Within a realtime environment.

-user agent supports the WTAI libraries, rendersWML, and executes WML Script.

2. A repository (storehouse or warehouse) providespersistent client side storage for WTA app. – that

retrieved or pushed from the WTA server prior touse.

-WTA app. Are stored as channels in the repository

-channels made up of entities-called resources-

includes WML decks, WML Script, WBMP (wirelessBit)map

3. Wireless telephony events and interfaces aresupported through the WTAI libraries

events- incoming call and call connected events



The WTA Client Framework• WTA client includes a user agent, the

repository, and a WTA application programminginterface.

Two user agents in the mobile client

1) Wireless Application Environment (WAE) useragent

2) WTA user agent – share the application

environment (fig13-4)

Fig(13-3)

Fig(13-4)



WTA Session• When the user requests a WTA application that is not

stored in the repository, the mobile client initiates aWSP session over WTLS to a trusted WAP gateway

• WTLS enables mutual authentication between the

client and gateway and provide over the air encryption

• Once the session is established, the WTA user agent

retrieves the services from the WTA server. The WAP

gateway can enforce the security policy of the

telecommunications service.• The WTA user agent can access content and receive

content through this secure pipe

E t h dli



Event handling• WTA user agent processes all network

events and directs them to an appropriate

handler within an application

• When a n/w event is received, the user

agent first attempts to perform local

binding , dispatching the event locally tothe event locally to the currently executing

program.

• An app. may bind an event to a handlerthat is invoked by the user agent when the

event occurs.



<!update the display when the call is beingconnected>

<onevent type=“wtaev-cc/cc”> <refresh>

<setvar name=“WMLMsg”Value=“callconnecting”/>

</refresh>

<onevent>

If the currently active pgm doesnot have adefined event handler for that event, the useragent next attempts to perform a global binding



The repository

• Repository is analogous to the level 2 cache in amicroprocessor-which contains most of thefrequently executed instructions for a program

• The processor can quickly load theseinstructions if there is a “hit” without having toaccess slower memory or the even slower diskdrive.

• The resource manager of the WTA user agentallocates memory in the repository and alwaysaware of the amount of available space.



The channel and associated resources can be

loaded into the repository by the following

methods-The application can be reinstalled into the

repository during manufacturing or during

subscription process at a customer care center.

-The WTA user agent can pull the channel and its

associated resources from the WTA server and

install the application in the repository

-The channel can be pushed directly from the WTAserver into the repository.

WTA li ti i i t f



WTA application programming interface• The WTA application programming interface consists

of two components:

– An event model- allowing the application to learn about andtake action on telephony actions.

– A subscription interface- allowing the application to initiateand control telephony operations

• Telephony events- when user makes a call or aincoming call is received, the WTA “network layer”generates a sequence of events.

• Two call models are used to describe the telephony

eventsfrom the voice network.1. Originating call model

2. Terminating call model



Network Common Libraries• N/W common WTA library contains fns

that apply to most wireless networks.

• Voice Control Events- allow the application

to manipulate telephone calls

• This group include the following fns – WTAVoicecall.setup(): Initiates a phone call to

the specified number

– WTAVoicecall.accept(): Accepts an incoming

or waiting call

– WTAVoicecall.release(): Hangs up a call that

is currently active.

– WTAVoicecall.sendDTMF():Sends a touch –



-WTAVoicecall.callStatus(): Information about a call,

including the remote phone number, remote party’s

name, call duration and current status

- WTAVoicecall.List(): Obtains a list of all currently activecalls on the deviceNetwork text message Handling –

network text message service-send, receive, store text

msg - Ex. SMS

- Library fns- WTANetText.send(): Sends a n/w text msg

- WTANetText.List():List of network text meessage

- WTANetText.remove(): deletes a network text msg

- WTANetText.getFieldValue(): Obtains the textualcontent, orginator address, timesstamp, or status of n/w

txt msg

- WTANetText.markAsRead(): Marks a network txt msg as

being read

Ph b k



Phonebook• Allow the application to access and manipulate the data

base of contacts stored on the device

• Phonebook as an array• Fns on the phonebook

– WTAPhoneBook.Write(): Writes a new phonebook

entry.

– WTAPhoneBook.search():searches the contack add.

– WTAPhoneBook.remove():Removes a specified

phone book entry

– WTAPhoneBook.getFieldValue():obtains a particular

field in a phone book entry

– WTAPhoneBook.change():updates a particular field in

a phonebook entry

C ll l



Call logs• Mobile automatically stores dialed

numbers, received calls, and missed calls

into its call log

• Each call log comprise an array of entries

• Fns on the call log

– WTACallLog.dialed(): Retrieves the log entry

for a recently dialed no.

– WTACallLog.missed():recently missed call

– WTACallLog.received():recently received call

– WTACallLog.getFieldValue():Obtains a

particular fieldfrom a call log entry



Miscellaneous Fns-WTAMisc

library• WTAMisc.setIndicator(): indications shown

on the client display

• WTAMisc.endcontext(): terminates the

current execution

• WTAMisc.setprotection():user agent

context can be interrupted by events

• WTAMisc.sgtprotection():retrieves the

protection mode



Network specific libraries

• Contain and events that apply only to

particular wireless n/w

• Ex GSM n/w

• WTAGSM-provides reject(),hold(),

transfer(), multiparty()



The WTA Server and Security

• WTA server- WTA applications in the form

of WML decks and WML script.

• Responding to requests- mobile client



Design Considerations• Performing network mapping, service design,

development, and testing

• Service concept- behavior and Interaction withthe user

• Network mapping- service is mapped to aparticular mobile network and the networkarchitecture

• Service design- service developer determineswhich pieces of app. Already resident in themobile client- service developer whether thoseresources can be reused- which new pieces

can be loaded.

N t k d i id ti



Network design considerations

• Real time loading Issues

• Acceptable perception of latency- usability studies- auser will wait at most six seconds after making a

request to see or hear

• Bearer Selection- used to retrieve the application,

among other things- each network offers a different

combination of latency and bandwidth

• Currently available bearer networks- SMS, CDPD,

CSD and GPRS• Memory Constraints- Small amount of memory in the

mobile client – general purpose, low power

microprocessor used in the client devices are clearly

getting faster.

Application Design considerations



Application Design considerations• Limited over the air bandwidth, memory

and computing resources are in the mobileclient

Developer must consider the followingissues.

• Partitioning• Repository

• Event Handling

• Network specific WTAI features• Error handling

• Delivery to the mobile client



Application Creation Toolbox

• Action/Event Construct

• Terminating call Template



Future WTA Enhancement



Future WTA Enhancement• In this section, we consider several potential

enhancements for future releases of the specification

• WTA server APIs-today- delivers WTA application tothe mobile client.

• It may be extended to support integration with the call

control features of mobile networks• External Device Events- future-users will want toextend the capabilities of the mobile terminal byconnecting it to external devices such as laptop PC or

PDA• Multiple context Support- future user agent ability toinstantiate a new context for each WTA call andDistribute events for both incoming and outgoing calls

• Improved Event handling

The Mobile Internet Future



The Mobile Internet Future• Better Content, Easier Access

• -Multimedia Content-Convergence with the

Web-through Extensible Hypertext Markup

Language(XHTML)

• Automatic Provisioning

• End to End Security

• Beyond Browsing

• Java,applets,java virtual Machine

• Asynchronous messaging and data synchronous• Access to Attached Devices



Beyond cellular

• Third generation Networks- 3G network

technologies occur by late 2000 -provide data

bandwidth exceeding one megabit per second

• Blue tooth-short range low power radiotechnology specifically aimed at portable

computing devices-mobile phones and PDA-Data

transmission rates 1 Mbps to maximum of 100 m

distance



Mobile Data Unleashed

• Connecting to people and information any

where, any time.

• They influence our lives at home, work,

school and play.

• WAP are endless- WAP will continue to

redefine mobility in the voice and data

communications world.



THANK YOU

“ALL THE BEST”

Wireless Telephony Applications

Documents

Transcript of Wireless Telephony Applications