iMode: Internet on the go

Intro-mode



By now we all know that WAP stands for Wireless Application Protocol (what

with all the hype surrounding it, it’s quite difficult to miss). But WAP isn’t

the only way you can access the Internet via a mobile phone. i-Mode, a mobile

phone service, also offers continuous Internet access. That was the good news,

now the bad news is that this service is restricted to Japan as of now.

To start right at the very beginning, i-Mode, in which the ‘i’ stands for

information, is a service that was launched in February 1999 by a company NTT

DoCoMo (DoCoMo in Japanese means ‘anywhere’), Japan’s leading cellular

phone operator. Instant access to Web sites compatible with i-Mode can be

achieved at the touch of a button. You could receive e-mail, exchange

photographs, receive news and stock quotes, shop online, receive weather

forecasts, play online games and access music files online. Every subscriber is

given an e-mail id, which is his or her cellular phone number @docomo.ne.jp. Of

course, amidst all this excitement of being able to access the Net on the go,

one tends to forget that you can also make and receive phone calls on a WAP or i-Mode

enabled phone.

HOW DOES IT WORK?



Components required for i-Mode services are:

• An i-Mode cellular phone i.e. a phone capable of voice and packet
  
  transmission along with a browser installed
• A packet network
• An i-Mode server
• Content in c-HTML

Mode of transmission



i-Mode uses a PDC-P (Personal Digital Cellular-Packet) method of data
transmission over the existing PDC network used for ordinary voice traffic. This

is a packet switched network that is well suited for wireless communication. In

a packet switched network, data is broken into small units called packets and

routed over the Net. This mode of transmission where communication is broken

into packets allows the same data path to be shared among many users in the

network.

Thus, users can stay online throughout and yet not be charged for the time

spent online. Rather, they only pay for the amount of data that they retrieve.

This is in contrast to the circuit switched network like the regular voice

telephone network where the communication path is dedicated to the callers thus

blocking that path to other users for that period of time.

The markup language



The markup language that i-Mode uses is cHTML or compact HTML which is a

subset of HTML and very similar to it. It is designed for devices with slower

connecting speed. One main difference between the two languages is that some of

the more resource intensive areas of the code such as tables and frames have

been bypassed in cHTML. This is understandably to reduce the download time to

mobile devices. So an i-Mode enabled Web site utilizes pages written in cHTML

and being similar to HTML, it is easy for Web designers to create. This cHTML

content needs to pass through a cHTML gateway before users can access it on

their mobile phones using the i-Mode browser. When an i-Mode compatible wireless

device makes a wireless request, the gateway translates this to the server and

back from the server to the wireless device.

Future mode



Just like the browsers, Internet Explorer or Netscape, used on a PC seek an

HTML page, the micro-browser in an i-Mode phone is a software designed to run on

a hand held device and used to access a cHTML page. As of now, the rate at which

data is being transmitted is 9.6Kbps but with DoCoMo going all out to develop

the W-CDMA or Wideband-Code Division Multiple Access technology, a third

generation mobile communication system, speeds of 384Kbps or more could be in

the offing. W-CDMA allows high-speed data transmission of video and large-volume

data.

From the security point of view, DoCoMo has formed an alliance with Sun

Microsystems to incorporate Sun’s Java, Jini and Java Card technologies into i-Mode

cellular phones. This provides enhanced security for critical applications like

online banking and trading and greater functionality allowing for game

downloading and interactivity with other devices.

Although i-Mode services are restricted to Japan, expectations are high that

their services will be further expanded to Europe, the UK, Asia and the US.

Whether NTT will be successful in making inroads into other parts of the world

remains to be seen.