Developing Mobile Wireless Applications

W hen we talk about Web content, we typically use document metaphors — saving our places with bookmarks, viewing and downloading pages, and so on. This metaphor feels natural because it originated in Web content, which is basically a collection of electronic documents laid out in a format familiar from books, magazines, and other publications. In the mobile world, however, developers quickly realized that " page " was not the best content metaphor. Small screens, limited bandwidth, and relatively little storage space prevent us from building large, complex page layouts. We thus prefer to think of our content as a deck of cards. A card, like a cell-phone or PDA, is small and might fit into the palm of your hand, for example. Also, like mobile device screens, individual cards offer relatively little space to write on — though you can write a little on each card and flip between them whenever necessary. This deck-of-cards metaphor underlies nearly all content developed for mobile wireless technologies. Standard, high-level application-development technologies , which are available for most major hardware platforms, ease this development task because they're optimized for the severe restrictions on a mobile device's screen size, processing power, and battery life. Here, we discuss three major application development technologies: the wireless application protocol (WAP), NTT DoCoMo's i-mode, and Sun's Java 2 Micro Edition (J2ME). Each lets developers create content for the current and upcoming generation of mobile wireless devices. WAP (www.wapforum.org) is a free, open specification that lets wireless devices easily interact with services and each other. It works over all major wireless networks and on all major mobile operating systems. In fact, renowned wireless technology providers such as Ericsson, Nokia, and Motorola are endorsing WAP for their 2.5G and 3G networks. Microsoft is also backing this mobile solution. Developers were slow to accept early WAP versions because of a steep learning curve and incompatibility with existing Web content. WAP 2.0 adopts existing Web standards, however, and specifies how developers can best use them in a wireless environment. WAP 2.0's aim is to improve the user experience as wireless networks slowly expand to allow richer content and cheaper bandwidth. Basic Features In theory, WAP 2.0 lets developers create applications that feature animation, streaming media, and music downloads. WAP 2.0 displays color graphics, provides location-specific content, and allows synchronization with a remote desktop PC. The goal is to reduce development costs by …