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System Architectures for Wireless & Internet

Application Systems

Speaker: Jerry Gao Ph.D.


San Jose State University

email: jerrygao@email.sjsu.edu

URL: http://www.engr.sjsu.edu/gaojerry


Topic: Wireless System Architecture

-

Basic Wireless Network Architecture


-

The Web Clipping System Architecture


-

The WAP
-
Based System Architecture


-

The Web ASP System Architecture


-

Extending Web to Wireless World


-

Wireless Enterprise Architecture


-

Design Issues Relating to System Architectures

Jerry Gao Ph.D.

9/2002

Presentation Outline

All Rights Reserved

Jerry Gao Ph.D.

8/2002

All Rights Reserved

Topic: System Architectures for Wireless & Internet
Application Systems

Network

Radio tower

Web Phone

Base Station

Switch

Mobile Switching

Center

Radio tower

Base Station

Phone

Mobile Switching

Center

Wireless Network Architecture and Its Major Components

VLR

HLR

EIR

AUC

Basic Wireless Network Architecture includes the following components:


Cell tower: A cell tower is the site of a cellular telephone transmission
facility. Wireless coverage of any city is generally divided into rough
hexagonal boundaries, with one cell tower to cover each region.


Base station controller (BSC)


A BSC controls a cluster of cell towers.



It is responsible for setting up a voice or data call with the mobile
terminal and managing handoff when the mobile unit transitions from
one cell tower boundary to another without disruption of service.


Mobile switching center (MSC). An MSC connects all the base stations
to pass communication signals and messages to and from subscribers
operating on the network.


Home location register (HLR). An HLR keeps track of information
regarding the subscriber. (such as last time connection, location,..)


Visitor location register (VLR). A VLR records information about
mobile units that have roamed into their network from other networks


that is, it tracks visitors.

Jerry Gao Ph.D.

9/2002

All Rights Reserved

Wireless Network Architecture and Its Major Components

Basic Wireless Network Architecture includes the following components:


Mobile identity number (MIN) and electronic serial number (ESN).


all phone equipment used in a wireless network carries these Ids. They
are used for verification, authentication, and billing purposes.


Equipment identity register (EIR). An EIR stores and checks the status
of MINs and ESNs.


Authentication center (Auc). An AuC is responsible for authentication
and validation of services for each mobile device attempting to use the
network.


Operations and Maintenance Center (OMC). An OMC is connected to
the network to provide functions such as billing, network management,
customer care, and service provisioning.


Redio Frequency (RF) transceiver. An RF transceiver is a combination
transmitter/receiver in a single package.

Jerry Gao Ph.D.

9/2002

All Rights Reserved

Wireless Network Architecture and Its Major Components

Jerry Gao Ph.D.

8/2002

All Rights Reserved

Topic: System Architectures for Wireless & Internet
Application Systems

PSTN

Cell tower

Web Phone

Base Station (BSC)

Switch

Mobile Switching

Center (MSC)

Phone

Wireless Network Architecture and Its Major Components

VLR

HLR

EIR

AUC

1. Outgoing Call

2. Setup connection

To BSC

3. Setup connection

To MSC

4. Query for authentication, service

Qualification, feature, location

5. Return information

6. Call routed to destination

Jerry Gao Ph.D.

8/2002

All Rights Reserved

Topic: System Architectures for Wireless & Internet
Application Systems

Internet

The Web Clipping Network Architecture

Data Center

PDA

Wireless

Data

Network

What is Web Clipping?


It is the proprietary language for Palm PDAs.


Users can access specific content on the Internet over BellSouth’s
Mobitex network (Palm.net) or use OmniSky’s data network (AT&T).


Palm also offers email applications for Palm VII.


Two key design principles:


Information transfer (user navigation and interaction) is based on simple
query and response (rather than hyperlinks). Each client request is in the
form of a query back to the server.


An application is partitioned so that the query portion resides on the
PDA (PQA).

Jerry Gao Ph.D.

9/2002

All Rights Reserved

Web Clipping Network Architecture

Key differences between WAP and Palm.net are:



A WAP user can browse any web site that handles WAP.Palm.net users. A
Palm.net user only can only access those sites that have been stipulated
as readable via a Palm Query Application (PQA), which must be
downloaded to the Palm device.


WAP applications can run over a wide range of networks


CDMA,
TDMA, CDPD, GPRS, Mobitex, and so on. However, only numbers
applications can be run on the top of Palm OS, including WAP
applications or applications for accessing a corporate LAN.


Jerry Gao Ph.D.

9/2002

All Rights Reserved

Web Clipping Network Architecture

To reach many kinds of wireless devices from your server, you must be able
to handle each device efficiently as a presentation device.

There are a number of useful approaches:


Using a server for each type of devices.


Simple but costly.


Using a page translator.

-

This approach is simple, but the end product has not been received
well by mobile users. We need an application built for them with
content edited to suit their mobile devices.


an XML application server.

-
This approach provides the maximum coverage and is the easiest
setup to maintain in the long run.

-
XML has great flexibility and deliver portable content from
application servers.

Jerry Gao Ph.D.

9/2002

All Rights Reserved

Wireless Publishing Framework

Jerry Gao Ph.D.

8/2002

All Rights Reserved

Topic: System Architectures for Wireless & Internet
Application Systems

Internet

The WAP
-
Based System Architecture

WAP Gateway

Bearer

Network

WAP Browser

Client

Server

WAP Browser

WAP
-
Based System Architecture includes the following components:


WAP Browser:


The WAP browser is similar to Web (HTTP) browsers. It provides a standard
user interface to various wireless internet users.


It interacts with mobile users based on WML (the Wireless Markup
Language) and WML Script (a scripting language for the WAP browser).


It access WML and WML Script content by specifying a URL. Furthermore, it
can access dynamic content via CGI and Java Servlets on the Internet server.


WAP gateway:

-

It is responsible for interfacing the wireless bearer network to

the wired Internet.

-

It enables WAP browsers to access standard HTTP servers.

-

It moves traffic between the bearer network and the Internet, therefore,
providing Internet traffic to the wireless devices.

Jerry Gao Ph.D.

9/2002

All Rights Reserved

WAP
-
Based System Architecture


Bearer Network:


Since wireless devices exist with a variety of IP and non
-
IP based
infrastructures. The primary function of the bearer network from a
WAP perspective is to connect individual wireless devices to a WAP
gateway.


Internet Server:


Internet server provides various kinds of Internet wireless content
services and application services to mobile users.


It provides web
-
based applications and web content to web users.


Internet Client:

-


Internet client software, such as web browser, which interact with
web users to support web accesses.

Jerry Gao Ph.D.

9/2002

All Rights Reserved

WAP
-
Based System Architecture

Jerry Gao Ph.D.

8/2002

All Rights Reserved

Topic: System Architectures for Wireless & Internet
Application Systems

The WAP Software Architecture

WAE



WSP


WTP


UDP




IP


Bearer

Network

WAE



WSP


WTP


WTLS


WDP



Bearer

Network

Application



Presentation


Session


Transport




Network


Data Link

Network(HW)

IP
-
Based WAP

Non IP
-
Based WAP

The WAP architecture consists of six layers:


Wireless Datagram Protocol (WDP)


It provides essentially the same services as the UDP in an IP network.


Wireless Transport Layer Security (WTLS)


It is the layer in the WAP architecture that is responsible for data integrity,
privacy, and authentication.


WTLS is similar to the industry
-
standard Transport Layer Security (TLS)
security protocol.


It has been optimized for use on bandwidth
-
constrained networks


Wireless Transport Protocol (WTP)


It is a lightweight transaction
-
oriented transport protocol. It provides three
classes of communications: a) unreliable one
-
way messaging, b) reliable one
-
way messaging, and c) reliable two
-
way transactions.


It has been optimized for use in bandwidth
-
constrained networks

Jerry Gao Ph.D.

9/2002

All Rights Reserved

WAP Software Architecture

Jerry Gao Ph.D.

9/2002

All Rights Reserved

WAP Software Architecture


Wireless Session Protocol (WSP)


It provides upper layers with two forms of services:


Connection
-
oriented service and datagram service.


Wireless Application Environment (WAE)


It is the layer of the WAP architecture that is of greatest interest to
the WAP Servlet developer.


At the layer, applications use the WSP to communicate with HTTP
servers on the Internet.


All applications pertain to specific types of WAP clients (phones,
pages, …)


Jerry Gao Ph.D.

8/2002

All Rights Reserved

Topic: System Architectures for Wireless & Internet
Application Systems

Internet

Cell tower

Web Phone

Microsoft Exchange

Lotus Notes

A Typical Web ASP Network Architecture

Conduit Server

Microsoft Exchange

Lotus Notes

Conduit Server

PDA

Firewall

Wireless

Network

Microsoft Exchange:


It is one of the predominant corporate electronic mail packages available
today.


Wireless Knowledge’s Workstyle Server allows corporations to connect
multiple Exchange servers with wireless handhelds and phones, so that
users can real mail, check their calendars, or look up their phone books
using mobile devices.


Lotus Notes:


Lotus mobile service for Domino software package from Lotus allows
mobile users to connect to their Lotus Notes applications like email,
calendar, address book, discussion database etc.


Jerry Gao Ph.D.

9/2002

All Rights Reserved

A Typical Web ASP Network Architecture

Companies, such as Wireless Knowledge and Saraide are becoming the
application service providers (ASP)s of the wireless world.


They hook up employees to corporate networks to provide access to email,
calendar, contacts, and intranet content.


Company



Mobile Offering


Wireless Knowledge


Connectivity to Microsoft Exchange Servers

Saraide



Messaging (synchronize with M.S, outlook,



and Lotus Schedule), news, travel, financial



services

Infinite Mobility


Hosting solutions

Jerry Gao Ph.D.

9/2002

All Rights Reserved

A Typical Web ASP Network Architecture

The system architectures differ depending on mobile devices:


WAP phones and Smart phones


Palm PDAs


WinCE PDAs (or Pocket PC)


Blackberry handhelds


Two approaches to place existing content on WML and/or HDML devices:



Rewrite all or sections of the Web Site into WML or HDML


Use rendering/extraction techniques to transfer existing content and then
apply transcoding to produce the content into multiple formats such as
WML, HDML, HTML, cHTML, and VXML.

Jerry Gao Ph.D.

9/2002

All Rights Reserved

Extending Existing Web
-
Based Applications

to Wireless Devices

Jerry Gao Ph.D.

8/2002

All Rights Reserved

Topic: System Architectures for Wireless & Internet
Application Systems

Internet

AvantGo’s Architecture

Data Center

BellSouth

Data Network

AT&T CDPD

Enterprise

Resources

Palm PDA

Commercial

Content

Palm PDA

Jerry Gao Ph.D.

8/2002

All Rights Reserved

Topic: System Architectures for Wireless & Internet
Application Systems

A Personalization Framework

PDA

Mobile Phone

Phone

Web Server

Rules and Logic

Engine

Content

Repository

Web Server

Logs

User

Information

& Preferences

Client

Stream Data

Device Capability

and Profile

Security Info

and E
-
commerce

History

User input

user navigation

Web Content, Email., fax,

Instant Message

Jerry Gao Ph.D.

8/2002

All Rights Reserved

Topic: System Architectures for Wireless & Internet
Application Systems

Internet

Web Phone

Architecture For A Wireless Enterprise Solution

PDA

Wireless

Platforms

Wireless MD


Application

HMO

Radiology

Labs

Hospital

Pharmacy

Physician

Pharmaceutical

Manufacturers

Web Users

Jerry Gao Ph.D.

8/2002

All Rights Reserved

Topic: System Architectures for Wireless & Internet
Application Systems

XML Publishing Server Publishing Framework

XML

Application

Server

Appliance

Web Phone

PDA, Handheld

Pager

Web PC

WML, cHTML, XHTML Basic

XML, HTTP, Java

SMS, IMAP, POP

VoiceXML

Voice portal

HTML, XHTML

XML, HTTP, Java

Jerry Gao Ph.D.

8/2002

All Rights Reserved

Topic: System Architectures for Wireless & Internet
Application Systems

The Speech Recognition Process

Capture &

Digitization

Wireless

Phone

Phone

Network

Spectral

Representation

and Segmentation

Feature

Extraction

Recognition

Communication

Wireless

Network


Speech recognition is a computer’s ability to receive and understand (process)
spoken commands and words.



Voice recognition is a computer’s ability to recognize a specific voice or
speaker and is used for security and authentication purposes.

Speech recognition systems have two functions:

-

understanding the words being spoken and then converting them into text for
further use.

-

converting text to speech for the purposes of information access


There are three basic components of speech recognition:


Capture and preprocessing (from analog signal
-
> digital format)


Recognition and feature extraction


analyze the acoustic signals and recognize common sound patterns
(phonemes)


Words, phrases, and sentences can be represented digitally (segmented and
restructured)


Communication with other application software and hardware

Jerry Gao Ph.D.

9/2002

All Rights Reserved

The Speech Recognition System and Components

Topic: Wireless System Architecture

What kind of spectrum and power?

( 20
-
year cycle )


-

what spectrum?


-

what power and speed?


-

anticipate standards. Evaluate WAN, LAN, and PAN utility.


-

decide wireless business model.



What is the network structure?

( 10
-
year cycle )


-

towers and base stations


-

network structure


-

match application to network data rates.


What kind of services?


( 5
-
year cycle )


-

identify servers and browsers?


-

design XML architecture, 3
-
tier services, and application server.



Jerry Gao Ph.D.

9/2002

Design Issues for Mobile
-
Based System Architectures

All Rights Reserved

Topic: Wireless System Architecture

What kind of mobile devices?

( 2
-
year cycle )


-

evaluate emulators and SDK.


-

prepare for devices and chipset capability.


What types of protocols?


-

air interface protocols


-

wired communication protocols


What kind of content?


( every season, month, week)


-

determine publication model, databases,


editing workflow, and information design


-

content layout, organization, and structure


Who are the users?


-

Evaluate user interface, voice, media, and data use


What technology?


-

Evaluate and select technology

Jerry Gao Ph.D.

9/2002

Design Issues for Mobile
-
Based System Architectures

All Rights Reserved

Topic: Wireless System Architecture

What is the security solution?


-

Network security (air security)


-

User access control


-

Secured communication, channels, sessions


-

Secured server and applications


-

Client security



What are the standards?



-

network standards


-

protocol standards


-

technology standards





Jerry Gao Ph.D.

9/2002

Design Issues for Mobile
-
Based System Architectures

All Rights Reserved