Wireless Protocols, Platforms and Programming Languages
Programming languages, platforms and protocols are pivotal development and implementation tools for wireless communications. Often, several protocols, platforms and program-ming languages are used simultaneously in a single wireless technology development. The lack of a unifying standard results in incompatibilities and obstacles similar to those asso-ciated with WAP/WML. The following sections examine protocols, programming languages, their uses and their unique contributions to wireless communications.
1. WAP 2.0
WAP 2.0, scheduled for release in 2001, is a revision of the Wireless Application Protocol. WAP 2.0 specifies XHTML Basic, a subset of XHTML, to replace WML as the markup language used by wireless devices to render Web content. This new W3C Recommendation benefits wireless device manufacturers, Web content developers and users. Manufacturers will have a de facto industry standard, allowing them to develop compatible mobile devices and applications. Content developers will be able to create Web pages for such platforms as diverse as mobile phones, PDAs, pagers, WebTV and desktop computers. In addition, wireless device users acquire access to a wider selection of content that is easier to navigate.
WAP 2.0 will likely include WML extensions that allow programmers to embed WML within the XHTML Basic markup. Features, such as soft keys that are not supported by XHTML Basic will be implemented using WML. In addition, the new protocol is also expected to include specifications for color, animation and such multimedia features as MP3 audio and MPEG video streaming.
2. Handheld Devices Markup Languages (HDML)
The Handheld Devices Markup Language (HDML) was one of the first markup languages used to deliver content handheld devices. HDML was originally developed in 1996 by a company called Unwired Planet, now known as Openwave (www.openwave.com).24
HDML is similar to Hypertext Markup Language (HTML), which is used to design and format Web pages. However, HTML is not effective for use on devices with limited screen sizes and viewing capabilities. Although HDML was implemented in millions of devices when it was first introduced, it has been replaced with other emerging standards that sup-port 2.5G and 3G technologies. HDML eventually evolved into WML.25
In Japan and parts of Europe, consumer wireless devices function using WAP and no longer support HDML. However, some CDMA-based phones in the United States and Canada still support both WML and HDML. The conversion of HDML to WML code is not difficult, and Openwave (HDML’s creator) is currently working to replace HDML with WML.
3. Compact HTML (cHTML) and i-mode
NTT DoCoMo and its popular i-mode service employ Compact Hypertext Markup Lan-guage (cHTML) to format Web pages. cHTML a subset of HTML that is designed for mo-bile devices, uses a limited set of HTML tags and attributes. With the exception of i-mode phones and devices, cHTML is not widely used. However, in the future, cHTML could merge with a form of WAP or XHTML Basic.
Previous sections of this chapter described the process by which WAP and WML com-municate with the Internet. using specific protocols and markup tags. Although the i-mode service functions similarly, there are a few notable differences. When a user requests infor-mation from the Internet via an i-mode phone, the request is sent directly to Web servers at NTT DoCoMo, which send the desired information back to the user. NTT DoCoMo main-tains over 30,000 pages of content designed specifically for the i-mode service, and this information is stored on the company’s own servers.
4. Java and Java 2 Micro Edition (J2ME)
Java is one of the most popular programming languages in the software-development in-dustry. Sun Microsystems created Java to facilitate the development of Internet and Web-based applications that can run consistently on any operating system without requiring al-teration. Sun coined the term, “write once, run anywhere™” to describe this feature.
Over the past few years, Java has matured into the Java 2 platform, which provides an even higher level of consistency among different systems. Java 2 has evolved into three platforms:
Java 2 Standard Edition (J2SE™), which enables developers to create standalone programs and client-side applications,
Java 2 Enterprise Edition (J2EE™), which enables developers to create powerful enterprise systems for the management of entire businesses, and
Java 2 Micro Edition (J2ME™), which enables developers to create applications targeted to consumer devices.
Java 2 Micro Edition is the newest option for Java programming. This platform enables developers to write applications for such consumer devices as set-top boxes, web terminals and embedded systems. However, much of J2ME’s popularity is attributed to the fact that developers can write applications for wireless devices. J2ME excels in assisting the devel-opment of applications for devices with limited resources (i.e., limited screen size, memory, power and bandwidth). J2ME also offers programmers tools to create user inter-faces, connect to networks (to send and receive data) and save various program information (such as phone numbers and e-mail addresses). For more information on J2ME, visit www.java.sun.com/j2me.
5. Binary Run-Time Environment for Wireless (BREW)
The market for wireless devices, especially cell phones, is exploding. Great demand exists for cell phones to support more functions; however, there are problems adapting applica-tions on the devices’ varying runtime environments. One possible solution is for manufac-turers to improve the hardware of mobile devices, enabling devices to support a larger number of applications. However, the costs associated with hardware improvements are ex-tremely high. To provide additional functionality relatively inexpensively, Qualcomm has developed Binary Runtime Environment for Wireless (BREW). This new application plat-form was introduced in May 2001.27
BREW is a layer of code that works with Qualcomm chips and other cell-phone oper-ating systems that allow cell phones to run application programs written using BREW development kits. Applications developed with the BREW standard development kit are platform-independent, allowing them to run on devices with varying runtime environ-ments. The simplicity of application development using BREW allows manufacturers to reduce costs and shorten development timetables. In addition, the platform enables soft-ware developers to create applications, including navigation assistance, instant messaging, e-mail, e-wallets, games and personal information management, that are be accessible through a variety of wireless devices.28
6. Bluetooth Wireless Technology
Bluetooth wireless technology enables low-power, short-range wireless communications between computers, PDAs, cell phones and other devices. This technology has the potential to reduce and even eliminate the need for wires in offices, homes, cars and elsewhere.
Bluetooth wireless technology communicates by using radio frequencies to create a personal area network (PAN) of connected devices, also called a piconet. Bluetooth tech-nology supports point-to-point communication, through which a Bluetooth-enabled device, such as a wireless phone, sends a signal to one other device, as well as point-to-multipoint communications, that connects one device to up to seven others. One Bluetooth device can recognize and connect to any other Bluetooth-enabled device within a 30 feet radius. For example, imagine that an employee uses a PDA to schedule a meeting with another user in the network. When both users return to their desktop computers, the information stored on their PDAs can be transferred to the users’ desktop computer calendars by using Bluetooth wireless technology instead of user commands. This eliminates the need for users to per-form a manual synchronization process later to update devices.
More than 2,200 companies are members of the Bluetooth Special Interest Group (SIG) (www.bluetooth.com). The SIG pools the patents of member companies and provides a free intellectual property license to member companies as long as the members submit products to qualification testing before sending their Bluetooth products to market.
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