WAP phones

WAP enabled phones allow to access the WWW through mobile phones. While this sounds good, it is currently not that good in reality.

Technical background:

WAP (Wireless Application Protocol) is a protocol similar to HTTP, which is used to transfer data from a host to cellular phones. As the bandwidth available is rather limited (usually 9600 bps), compression is an important issue. Also the connection is much more unreliable than in the Internet and it must also cope with problems like changing the sender of the information if the user moves from one cell to another.

While WAP is the equivalent of HTTP, WML (Wireless Markup Language) replaces HTML for the description of the information, which is sent over WAP. WML is based on XML, so conventional XML-Browsers should also be able to display WML pages. The introduction of WML was necessary, as handy suffer from a special problem (see also below), the small display size.

Because of the different protocols used, cellular phones cannot access a webpage directly. They need a transformation from HTML to WML, which is done by the network provider of the phone. As this change of format will usually be of rather low quality if it is done automatically, it is necessary to provide important information in native WML format, which will be much more suitable to the display of the phone.


The problems of WAP phones are numerous:

Display size: The most significant problem is the display size (e. g. 96x65 pixels). If assuming a text-only interface, this accommodates approximately 8 lines with 12 characters each in good quality letters. It is obvious, that not much information can be displayed on such a small screen. Compare this with an very old-fashioned computer, who has at least 25 lines of text a 80 characters. Working on them was possible, although a graphical UI was not used. Because of this small amount of information on display at once, there are severe consequences: If the information is presented as a tree, the user has to go to a very high depth, to reach the actual information. If it is organized like a list, a large number of pages must be scrolled away. Both modes take a heavy toll with them: The user will probably often not know, where he actually is and restart from the top. Moreover, navigation is time-consuming.
User interface: Cellular phones have (out of necessity of being small and lightweight) few and small buttons. This is a severe restriction to the user interface. While this might be no problem for only passive communication (the user looks at predefined WML-pages), it is probably next to impossible to enter a text in a form with a handy. In this way, a very important part of the WWW, the ability to interact and participate, is cut off. Some might say, but this won't be needed in the future, we will just use voice-input! But this will not work in many cases: Suppose you are sitting in a bus: What will happen if both you and your neighbor try to tell your/his handy, what to do. The sound-level will rise, and all phones will be confused by the mass of input they receive. This is because writing a text has no ambient property, it is a strict one-on-one relationship, while voice is inherently a one-to-many relationship. Therefore I don't think, that voice-input will be a really viable solution.
Control of content: Currently, your provider for the cellular phone controls only when and where you communicate, but he cannot control the content of your communication. In contrast to this, with WAP he also provides the transformation of the WWW-pages to WML pages or the pages itself. This is not an optimal solution, if access and content provider merge to a single instance. However, this problem might disappear over time, as more and more Pages in the Internet directly provide WML pages. In these cases, the phone-provider moves back to a simple access provider.
What is important enough, to be needed on the phone: Only few information will be necessary to be accessible through a mobile phone. The information should be mostly independent from user input and rather small. These restrictions reduce the amount considerably. Only quickly changing information, which might be needed either on the spot or only in special cases (but then immediately) is useful for WML representation. In connection with this it is necessary to mention, that WML pages are the same for other WAP-enabled devices, which offer e. g. larger screens and more buttons.

Usability for mobile work:

Because of the problems mentioned above, I don't think these phones are of real use for mobile work. They might help in certain cases but generally this technique will be used by consumers or as a status symbol. Because most work is interactive, the mainly unidirectional WAP-phones will not be suitable for carrying it out.

Use for mobile work might be in the area of delivering short information to mobile workers from a central bureau: The timetable or customers to visit could be published on private WML-pages, which the employees can look up from wherever they are. But as those workers will usually carry also a laptop, this is not a necessity: They could also access them through a conventional webbrowser using the phone only for the data transfer (but in this case without the help of compression and reduced information).


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Last modified: 13 August, 2002 , by MVS