Jan Schaumann <jschauma@netmeister.org>

[netmeister.org] [netmeister's PalmStuff]


The latest trends in wireless technology are (finally) freeing us from the constraints that wires and desktop computing have placed on our access to information and services. Now we can execute transactions and communicate anytime and anywhere, through cell-phones and PDA's, devices already in use by over thirty million Americans. As emerging technologies are making mobile computing as easy as working from our office, many aspects of the wireless Internet are constantly changing. Several different protocols are attempting to standardize the means through which server-based software applications communicate with mobile phones and PDA's to carry out administrative and service-related tasks.

The two main protocols competing for the large market of 3rd Generation Appliances are WAP and i-MODE. This article compares these two protocols, outlining their differences as well as their respective advantages and disadvantages. These exciting new technologies will clearly change the mobile and wireless market, but before we can investigate in how far and to what extent, it is first necessary to outline the definitions of each.

What is WAP?

The two core challenges of bringing the Internet to mobile devices are one the one hand how to interface between wireless carriers and the TCP/IP based Internet and on the other hand how to present the information of the various services on the handheld appliance. To overcome these challenges, the Wireless Application Protocol (or WAP) is envisioned as a comprehensive and scalable protocol designed to use with mobile phones using Short Message Services (SMS), General Packet Radio Services (GPRS), CDMA and GSM.

WAP in detail

WAP has been created by a consortium of Phone.com, Ericsson, Motorola and Nokia. It is therefor no surprise that Phone.com's WAP-based micro-browser is some kind of a standard on most WAP-enabled devices. But let's take it one step at a time - how exactly does WAP work?

WAP enabled phones or PDA's completing the information transfer between the Internet and the handheld device are following a two-step procedure to present the contents of the web site or the response from the service-provider on a screen with limited size. One of these two steps involves a so-called "WAP Gateway", the other the micro-browser:

The micro-browser is installed on the device to handle the responses, which are transmitted in Wireless Markup Language (WML). WML, while strongly resembling actual HTML, is in fact an XML (eXtensible Markup Language) application. WML follows a stricter syntax than HTML and allows for the use of variables, which greatly improves the functionality of the code.

The request is passed to a special piece of software found on networks called a "WAP Gateway". These gateways are installed by the service provider to interface between the Internet and the different mobile, non-voice services such as Short Message Service, Circuit Switched Data and GPRS. It retrieves the information from an Internet server in either standard HTML format or in "wireless-ready" WML. If the information received by the gateway is not in WML, the gateway will try to convert it as good as possible. Some contents may of course not be able to be converted correctly. The output of the WAP-Gateway is transmitted to the client, where it is rendered for display by the micro-browser as described above.

The intricacies of WAP - its capabilities, requirements and limitations - will, most likely, to a large extend govern mobile usage for the next few years. A research on the usage of WAP lead to the presumption that ``by 2004, one-third of all Europeans - more than 219 million consumers - will regularly use their mobile phones to access Internet services'' [13]. In the US, where cell-phone usage currently lies within a mere 3% of the population, research predicts an increase to roughly 78% - a huge market, that quite likely will be influenced strongly by WAP-capabilities of the new 3rd Generation devices.

What is i-MODE?

i-MODE, in contrast to WAP, has not been developed by a consortium, but by a single company, NTT DoCoMo 1. It follows a different approach to enable users to access IP-based services through their wireless device. As i-MODE is based on packet data transmission technology, a device using this technology is constantly online. Users ``are charged only for how much information they retrieve, not how many minutes they are using it for.''[2].

i-MODE in detail

As a very young technology, i-MODE was first offered in Japan in February 1999, and obtained over six million subscribers only 14 month later. Similar to the WAP-services as described above, the user needs an i-MODE enabled device, such as a Smart Phone in order to use the service. The transmission of the information utilizes the Code Division Multiple Access (CDMA) protocol. Since the transfer rates for data is still significantly lower than the average modem, i-MODE is insufficient for videos and large images, it is mainly appropriate for email and simple graphics.

In order to render the incoming content on the small display available on todays PDA's and wireless devices, i-MODE uses a subset of the HyperText Markup Language (HTML) used on the World Wide Web. Even though i-MODE does not require normal web pages to be converted into this compact HTML (cHTML), most pages designed for i-MODE enabled devices usually contain some of the special i-MODE-only tags supported by cHTML. Amusingly enough, DoCoMo also incorporated some special characters into this HTML-subset - character, ``which are symbols for joy, kisses, love, sadness, hot spring baths, telephone, Shinkansen train, encircled numbers etc.'' [7]

Some Numbers

At present (November 2000) the world's wireless internet users are distributed approximately as follows (percentages):

At present (November 2000) the world's wireless internet users are distributed approximately as follows (subscriber numbers):

At present (November 2000) the world's users of WAP based wireless internet systems are distributed approximately as follows:

All numbers are taken from [7].

Differences between WAP and i-MODE

By looking at the numbers above, it becomes clear why i-MODE is so successful: the vast majority of all wireless internet users is in Japan, where i-MODE is the dominant protocol. However, i-MODE is available only in Japan - Europe, another big market for 3rd Generation Mobile Service Providers is completely WAP-based. The US-America market, which had fallen behind originally is now catching up on these new technologies, and it appears that most service providers choose WAP as well. But what are the differences between the two protocols, aside from the technical details as described above?

The most basic difference that comes to mind, are obviously the different graphic-capabilities. While it is true that i-MODE only supports simple graphics, that is far more than WAP allows. i-MODE's packed switched data network is more suited for transferring data than WAP's circuit switched network. However, many people argue that these new services are mainly for small devices, mostly used ``on the go''. Following this argumentation, it is assumed that extensive graphic-support is not necessary, since most of what people might want to do over their wireless phone would be checking their email, some stock-quotes, weather- or traffic reports and the like.

Another major difference is the ``always-on'' capabilities of i-MODE. Since users are not charged for the time they spent online (after all, they always are), it does not only seem more convenient, but also cheaper than having to pay for time spent online. Since there is no need to ``dial-up'' before using the various IP-based services, ``E-mail will become as instant as Short Message Service (SMS)'' [2]. Again, it seems that i-MODE has the clear advantage here.

On the other hand, let's investigate the different Markup Languages utilized by the two competing technologies. i-MODE, as we know, uses cHTML, a subset of HTML, while WAP uses WML, a subset of XML. cHTML, while certainly easier to develop in from a web-designers standpoint, has its limits. The downside of WML, on the other hand, is similarly obvious - currently, a WAP-Gateway is required to translate between HTML and WML for almost every data-transfer. On the other hand, since WML is derived from XML, it is much more extensible. Furthermore, it is assumed that XML will in some respect replace HTML in the future, since it allows for more dynamic content and various different applications. If this trend proves to be true, it might be a hint that a WML-based service will, in the future be of more advantage than an HTML-based one. So while WAP may currently require more complicated technology, it may, in the long run, enable the user to do more with his device.

Survival of the Fittest

When discussing the different technologies, protocols and standards of 3rd Generation Mobile Services, it is important to keep in mind that these are all emerging technologies. WAP as well as i-MODE are currently in their infancy, and it is hard to predict the turns either or both of them might take during their development into a mature standard for wireless IP-based services.

Many people would like to enjoy the ``best of both worlds'', and while this is currently not possible, it might well be in the future. WAP, with all its big names (Motorola, Nokia, IBM, Ericsson and others) in the industry backing it up, might convince NTT DoCoMo that it is in the interest of all parties to join forces together to develop a new, better standard together. Or maybe other technologies will emerge of which one of the two protocols will benefit, while the other will not be able to keep up with the changes - who knows. Only time will tell which technology we will be using once the `` mobile Internet will be in our pocket [...], when we'll be video-conferencing and playing 3D games.'' [3]


Krithi Aiyappa, WAP Vs i-Mode: The big fight, http://www.ciol.com/content/technology/techbytes/100092101.asp

Tom Fitzpatrick, WAP and i-mode: A Comparison, http://www.allnetdevices.com/wireless/opinions/2000/09/15/wap_and.html

Tom Fitzpatrick, WAP vs. i-Mode, http://www.paralleldevices.com/archive/news/20000918419.asp

Elisa Batista, WAP or I-Mode: Which Is Better?, http://www.wirednews.com/news/technology/0,1282,38333,00.html

Various http://www.cellmania.com

Kenzo Fujii iMode, http://www.fujii.org/biz/csom/imode.html

Various, http://www.eurotechnology.com/imode/

Unknown, Imode - Japanese version of WAP, http://www.cellular.co.za/imode.htm

Niraj K. Gupta, i-mode shows the way, http://www.angelfire.com/nd/ramdinchacha/JUL00.html

Clifford Swift, Will WAP and i-mode converge?, http://www.itweb.co.za/sections/columnists/m-people/swift001026.asp

Various, http://www.wap.de

Various, The World Wide Web Consortium, http://www.w3c.org

Various, Your guide to the wireless Internet, wap phones, wap services and PDAs, http://www.wap.com

About this document ...

WAP vs. i-MODE

This document was generated using the LaTeX2HTML translator Version 99.2beta8 (1.43)

Copyright © 1993, 1994, 1995, 1996, Nikos Drakos, Computer Based Learning Unit, University of Leeds.
Copyright © 1997, 1998, 1999, Ross Moore, Mathematics Department, Macquarie University, Sydney.

The command line arguments were:
latex2html -split 0 WAP_iMODE.tex

The translation was initiated by Jan Schaumann on 2000-12-06


... DoCoMo1
DoCoMo, a play on the Japanese word for "anywhere", is Japan's largest wireless service provider. The "i" in "i-MODE" has been interpreted to stand for "information", "intelligent" or "internet"

Jan Schaumann 2000-12-06