6.2 Pervasive clients

Pervasive, mobile, wireless and many other terms constitute a confusing terminology which makes it difficult to have a common understanding of our topic. The problem always starts with classifying sophisticated systems, when it is discovered that the terms mean different things to different people.

Mobile in this context means that the information is not only accessible from a desktop browser but also from different types of devices, using different connections, from different locations. Wireless means you are not connected to the network using a cable. Mobile clients include wireless devices such as phones, pagers , and PDAs. Pervasive computing is computing power freed from the desktop. It's a step ahead in the mobile and wireless arena. It could be embedded in wireless handheld devices, automobile telematics systems, home appliances, commercial tools-of-the-trade or a smart card that you carry with you. Pervasive computing is convenient access to relevant information with the ability to easily take action on it, when and where you need to.

6.2.1 Architecture

Support for mobile clients impacts the runtime topology and therefore must be designed and implemented using best practices for system architecture. The good news is that any past investment in Web architecture to support Internet-based applications can be extended to support mobile clients.

A Wireless Application Protocol (WAP) gateway is used between the mobile client device and the Web server. The gateway translates requests from the wireless protocol into HTTP requests and, conversely, converts HTTP requests into the appropriate device format.

6.2.2 WAP

WAP is the Wireless Application Protocol. This is the standard for presentation and delivery of information to wireless devices, which are platform, device and network neutral. The goal of this protocol is to provide a platform for global, secure access through mobile phones, pagers, and other wireless devices.

6.2.3 Microbrowser

WAP microbrowsers run on mobile clients. They are responsible for the display of Web pages written in WML and can execute WMLScripts. These play the same role as HTML browsers that run on a PC.

6.2.4 WML

The Wireless Markup Language (WML) is based on XML and HTML 4.0 to fit small hand-held devices. It is a tag-based language that handles formatting static text and images, can accept data input, and can follow hyperlinks . WML also uses WMLScript, a compact JavaScript-like language that runs in limited memory. WML is the markup language of WAP.

The WML specification is maintained by The Open Mobile Alliance. The Open Mobile Alliance has been established by the consolidation of the WAP Forum and the Open Mobile Architecture Initiative, two industry-wide consortiums concerned about the development of an open standard for the wireless industry.

For more information, you can visit The Open Mobile Alliance Web site at:

http://www.openmobilealliance.org or http://www.wapforum.org

6.2.5 WMLScript

This is the companion language to WML, in the same way that JavaScript is a companion language to HTML. WMLScript allows for procedural programming such as loops , conditional and event handling. It has been optimized for a small memory footprint and small devices. This language is derived from JavaScript.

6.2.6 cHTML

cHTML stands for Compact HTML and is a subset of the HTML specifications targeting small appliances such as smartphones and mobile PDAs. The cHTML tries to bypass several hardware restrictions by providing a standard markup language and small browser that could be executed in a constrained environment with a small memory, low power CPU, a small display, etc.

Since the Compact HTML is based on standard HTML recommendations from W3C, we can develop and apply software tools to adapt pure HTML to cHTML, making Internet information available and adequately formatted to new classes of devices and appliances. Basically, cHTML excludes JPEG images, tables, image map, multiple character fonts and styles, background color or images, frames , and cascading style sheets from the HTML specification.

cHTML is the markup language of i-Mode. i-Mode is a wireless service developed by NTT DoCoMo in Japan. It is designed to provide mobile phone voice service, Internet and e-mail access.

For more information about Compact HTML, you can read the document submitted to W3C, World Wide Web Consortium, at:

http://www.w3.org/TR/1998/NOTE-compactHTML-19980209 .

6.2.7 VoiceXML

The Voice eXtensible Markup Language (VoiceXML) is an XML-based industry standard language for creating voice applications, much as HTML is a language for developing visual applications.

VoiceXML is defined and promoted by an industry forum, the VoiceXML Forum, founded by AT&T, IBM, Lucent and Motorola, and currently supported by more than 570 member companies.

VoiceXML was designed to create audio dialogs that feature text-to-speech, digitized as well as prerecorded audio, recognition of both spoken and dual-tone multi-frequency (DTMF) key input, recording of spoken input, telephony, and mixed-initiative conversations. Its goal is to provide voice access to Web-based content and applications. It enables the development of voice applications via the use of a familiar markup style and Web server-side logic to deliver applications over telephone lines. The resulting applications allow conversational access to Web-based data, and can also interact with existing back-end business data and logic.

A VoiceXML application is capable of retrieving information from a Web server and, by making use of scripts and appropriate grammars, the application can interact with the customer through spoken words.

For more information, you can visit the VoiceXML Forum Official Web site at:

http://www.voicexml.org

X+V

X+V is an abbreviation of XHTML + VoiceXML and it is a markup language specification submitted to the World Wide Web Consortium (W3C) by IBM, Motorola and Opera Software to simplify the development of multimodal applications.

Multi-modal access will give users of pervasive devices (smartphones, PDAs, kiosks , set-top-boxes, etc.) a range of options for interacting with an application. To input information, they might use some combination of voice, keypad, stylus, touchscreen, and the application would deliver information using a combination of speech synthesis, text, graphics, A/V, etc.

X+V allows you to operate in a voice-only environment; in a visual-only environment, and if you want, in a multimodal environment.

6.2.8 SyncML

SyncML stands for Synchronization Markup Language and it is a an open standard protocol for data synchronization optimized for wireless networks. The SyncML consortium is sponsored by IBM, Nokia, Symbian, Ericsson, Matsushita, Motorola, Nokia, Openwave, Starfish Software and Symbian. It is being supported by the leading wireless companies including Apple Computer, Siemens AG, Vodafone Group, France Telecom and America Online.

The goal of SyncML is to enable synchronization of any type of data, from any application, on any device, and over any network. It has been designed to cope well with the specificities of mobile phones such as low bandwidth, unreliable connections and high network latency.

For more information, you can visit the SyncML Official Web Site at:

http://www.syncml.org

6.2.9 Mobile devices

Today, we have thousands of mobile devices to choose from. Mobile clients include wireless devices such as phones, smartphones, PDAs and even laptops. When deciding which one is more suitable for your specific application, you should analyze several factors such as the mobile platform, the mobile application platform availability device and network connectivity options. The goal is to overcome some device limitations to provide access to information and application services from anywhere .

Mobile devices include wireless desktop PCs, WAP devices, i-mode devices, PDAs, and Phone w/Voice. PDA devices cannot run the major operating systems that run on desktop PCs and consequently there are various mobile device-specific platforms. Palm devices use Palm OS. WinCE/PocketPC devices use a version of Microsoft Windows called Windows CE.

Voice-enabled applications allow for a hands-free user experience unencumbered by the limitations of computer interface controls.

Voice technology fall into two categories: those that recognize speech and those that generate speech. The ability to recognize human voice by computers is called Automatic Speech Recognition (ASR). The ability to generate speech from written text is called speech synthesis or Text-to-Speech (TTS).

Mobile devices categories

We have placed the mobile devices into three categories to better describe the specific features that they offer: mobile phones, smartphones and PDAs.

Mobile phones

When we refer to a mobile phone in this redbook, we are talking about a cellular phone that has a microbrowser to access Internet content. A standard cellular phone includes voice capabilities, messaging features (SMS or WAP push) and data functionality (can access Internet content through a microbrowser).

When selecting a device to a new application, you should also consider some industry-specific ruggedized devices. They have similar PDA functionality but they are more robust to work in hazard environments. Symbol and Intermec are two manufacturers specialized in these devices.

Smart phones

This is a generic name for voice-centric mobile phones with information capability. It's a hybrid device that combines the PDA and cellular phone functionalities. Several models have been launched recently and we expect to see more new models.

PDA (Personal Digital Assistant)

A Personal Digital Assistant (PDA) is a handheld computer with a wireless interface that serves as an organizer for personal information. PDAs often have a pen-based stylus to tap selections on menus and to enter printed characters . The unit may also include a small on-screen keyboard that is tapped with the pen. Data is synchronized between the PDA and desktop computer via cable or wireless transmission. We are interested in PDAs that have wireless transmission capability and include a Web browser. The major operating systems for PDAs are Palm OS, Epoc, and Windows CE.

Wireless laptops

This category includes laptops, notebooks , or portable PC browser clients that have a wireless interface to the network for Internet access. These clients use standard TCP/IP protocols and a standard browser, such as Netscape Navigator or Microsoft Internet Explorer. The wireless connection is usually much slower than wireline-based network clients.

6.2.10 Mobile client platforms

There are numerous mobile client platforms on the market today. They all target the same objectives: small footprint, optimized user interface, simple operation. This section gives a quick overview of the most common mobile client platforms.

Microsoft Pocket PC

The PocketPC operational system is based on the Microsoft Windows CE 3.0 (WinCE) operating system. It's is similar to the well-known Windows operating system, but optimized and developed especially for PocketPC mobile devices.

For more information, you can visit the Microsoft Web site at:

http://www.microsoft.com/mobile/pocketpc

Microsoft Windows Smartphone platform

Like PocketPC, Microsoft a smartphone platform also based on Windows CE V3.0. It combines voice and text communication and data applications with a similar look and feel. Like the J2ME and BREW platforms, it can run online and disconnected applications.

For more information, you can visit the Microsoft Web site at:

http://www.microsoft.com/mobile/smartphone

Palm OS

The base for this solution is not the device, but the operating system (OS). The OS called PALM OS is used with a wide range of devices, including the Palm, Sony and HandSpring devices. This device has built-in mobile capabilities, and works as a mobile phone with a data connection.

Like many other operating systems on the market, the Palm OS comes in different editions. The most widely used editions are V3.x and the latest, V4.0. All the versions are improvements on the previous versions. It is important to note that some of the software relies on a specific version of the OS.

For more information, you can visit the Palm OS official Web site at:

http://www.palmsource.com .

Symbian OS

Symbian is an open standard operating system for data-enabled mobile phones. It includes a multi-tasking multithreaded core , a user interface framework, data services enablers, application engines and integrated PIM functionality and wireless communications. It is present in several smartphones including Ericsson R380 Smartphone, Nokia 3650, Nokia 9290 and 9210 Communicator, Nokia 3650.

For more information, you can visit the Symbian Web site at:

http://www.symbian.com .

J2ME

J2ME stands for Java 2 Platform Micro Edition; it is a very small Java application environment suitable for several segments such as a TV set-top box, mobile phones and PDAs. The J2ME platform is composed of standard Java APIs and runtime environment to handle the user interface, security and network protocols. It also support online and disconnected applications; for example, handset users can download and run applications in the devices themselves , without the need for a continuous connection. The Motorola i85s and Nokia 8910i are examples of handsets with J2ME support.

For more information, you can visit the SUN Microsystems J2ME official Web site at:

http://java.sun.com/j2me .

Java Midlet

Midlet stands for Mobile Information Device Application. The latest generation of mobile phones uses a reduced version of J2ME. This version of Java has been specifically adapted for mobile information devices (MIDs), including mobile phones under the MID Profile.

BREW

BREW stands for Binary Runtime Environment for Wireless and it is an application platform execution environment for wireless devices developed by QUALCOMM . The BREW platform is part of an end-to-end solution for wireless applications development, device configuration, application distribution, and billing which will enable services providers and carriers ' customers, for example, to download new applications over the air and pay for them. The target devices are cellular phones like Motorola T720 and Samsung SPH-X2700.

For more information, you can visit the Qualcomm BREW official Web site at:

http://www.qualcomm.com/brew .