Getting into i-Mode

September 20, 2000

Didier Martin

If you've been reading about the wireless Web recently, you've probably heard about i-Mode. If so, you'll have heard that i-Mode is very popular in Japan, that about 11 millions users subscribe to it, and that it is growing at the rate of 45,000 new subscribers per day. However, unless you've traveled to Japan, it is unlikely that you've direct experienced an i-Mode device. This article explains what the fuss is all about.

i-Mode is foremost a brand, not a technology. This brand is owned by NTT DoCoMo, Japan's largest ISP. In some ways, i-Mode is equivalent to AOL: both are a brand representing a service or family of services. Until now, DoCoMo's advertising focused more on entertainment than on business applications. As is the case for the wired Web based mostly on PCs, the i-Mode killer app is email, comprising nearly half of the total traffic.

If we look at the technology, the i-Mode service is based on packed switched overlay over circuit-switched digital communications. In contrast to most European or North American WAP services, it is based on TCP/IP, is always on, and hence does not require a dial-in connection. The content is encoded in an HTML variant named cHTML (Compact HTML).

From the marketing point of view, i-Mode is incredibly popular. It went from zero to eleven million subscribers in about a year and a half. (I ought to add, however, that there are about 60 million mobiles phone users in Japan.) Mobile phones are less expensive than land phones, especially considering installation costs. Surprisingly, there are also more WAP users in Japan than anywhere else. In fact, the Japanese wireless Internet market is the biggest in the world. According to Eurotechnology, the approximate market share for wireless Internet is represented in this graph.

Source: Eurotechnology Japan K.K.

Recently, DoCoMo entered into partnership with Sun to port Java. i-Mode devices will be able to run Java applets, allowing new kinds of applications like games or web agents to be delivered to subscribers. At present, the i-Mode data transfer rate is 0.6 kbits/sec. But in 2001, NTT DoCoMo will improve its infrastructure by moving to third generation wireless, with a data transfer rate of 384 kbps for download and 64kbps for upload.

Again, in contrast to WAP devices that are still in black and white (or, I should say, green and black), some i-Mode devices have a color display with 256 colors. These devices can display GIFs and even animated GIFs. And, because only 3 to 5% of Japanese people speak English, i-Mode users are using Japanese. Most of the i-Mode handsets support phonetic text input. For instance, the number "1" is associated with the following phonemes: a, i, u, e, o. So it's probably easier to enter text with a phonetic base than it is with the alphabets; but seeing people typing the text, it doesn't seem to be any easier than with WAP devices. However, Japanese teenagers are typing on these devices like pros, and you should see how fast they are at writing emails by one-fingered typing.

Let's move on and take a look at cHTML, the rendering technology in i-Mode.

cHTML--a variant of HTML

A cHTML document is like an HTML document. In contrast to a WAP document, which contains more than one screen (i.e. cards), a cHTML document contains only one screen. Thus, the cHTML rendering model is identical to the HTML rendering model: one page at a time.



<META http-equiv="Content-Type" content="text/html; charset=utf-8">

<META name="CHTML" content="yes">

<META name="description" content="sample cHTML document">

<title>Sample cHTML document</title>


<body bgcolor="#ffffff" text="#000000">

<center>Didier's lab</center>



<a href="Messages" accesskey="1">1.</A> Messages<BR>

<a href="Mail.htm" accesskey="2">2.</A> Mail<BR>

<a href="" accesskey="3">3.</A>

Eurotechnology cHTML page<BR>



<A href=""></a><br>




The first thing to notice is that cHTML is unfortunately not XML-based. This is why, in the document above, the element <hr> is not <hr/>. The cHTML language is similar to HTML and was submitted to the W3C as a Note in 1998. It was designed for low memory footprint applications and so excludes things like tables and frames. cHTML has been adapted to the profiles of particular mobile devices by manufacturers. For instance, notice that the links are a bit different; a new attribute has been added: accesskey. This tells the phone browser to associate this link with a key on the keypad. It is easier to select a link with a single key press. (For further information, see DoCoMo's tag reference.)

Since a cHTML document is so similar to an HTML document, an XSLT style sheet can be used to transform an XML document into cHTML, in the same way that we already transform XML documents into HTML. Thus, the <xsl:output method="html"/> element can be used to specify the cHTML output type.



cHTML Submission to the W3C
i-Mode Markup Reference
i-Mode Resource Center

The world's largest wireless Internet boom is happening in Japan, rather than North America or Europe. One factor in this may well be the billing mechanism. An important difference between the i-Mode billing system and conventional models is that with i-Mode fees are based on the data transferred rather than connection time. Ten years ago the Baby Bells did an experiment with Minitel-like terminals, with precisely the same billing system as the European and North American Wireless network: time-based billing. From this experiment they learned that North Americans prefer fixed payments. It seems that this lesson has been learned by wired Internet providers since most of them in North America charge a fixed fee. It seems that this lesson has not been learned by wireless Internet providers. The question to ask now is whether North American users prefer fixed charges for the wireless Internet? I do not pretend to know, but the answer to this question will have a large impact on the success of the wireless Web.

Another issue to be resolved for WAP devices is screen size. It seems that most of the i-Mode devices available on the market offer bigger screen space than WAP devices. Surfing the wireless Web with this kind of device is more comfortable than with tiny three lines.

One thing is certain: while the wireless Web is taking shape in Japan and in Korea, Europe and the USA are lagging behind. My opinion is that in order to take off in North America, the wireless Web needs to resolve these issues:

  • the usage fees (fixed charges, minutes, per packets)
  • the screen size

Perhaps the data input method needs more thought, too. But after seeing Japanese teenagers adapting to one-fingered typing, maybe European and North American teenagers can adapt to it too. Who knows?