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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.
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.
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].
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]
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].
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.
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]
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