Mobile

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This chapter appears in the publication, International Journal of Information Technology and Web Engineering Volume 1, Issue 1 edited by GhaziAlkhatib and David Rine © 2006, Idea Group Inc.

Engineering Wireless Mobile Applications
Qusay H. Mahmoud, University of Guelph, Canada Zakaria Maamar, Zayed University, United Arab Emirates

ABSTRACT
Conventional desktop software applications are usually designed, built, and tested on a platform similar to the one on which they will be deployed and run. Wireless mobile applicationdevelopment, on the other hand, is more challenging because applications are developed on one platform (like UNIX or Windows) and deployed on a totally different platform like a cellular phone. While wireless applications can be much smaller than conventional desktop applications, developers should think in small terms of the devices on which the applications will run and the environment in which theywill operate instead of the amount of code to be written. This paper presents a systematic approach to engineering wireless application and offers practical guidelines for testing them. What is unique about this approach is that it takes into account the special features of the new medium (mobile devices and wireless networks), the operational environment, and the multiplicity of user backgrounds;all of which pose new challenges to wireless application development. Keywords: mobile technologies; process design; screen design; software design; testing activities; testing issues; wireless technologies

INTRODUCTION
The general mobile computing model in a wireless environment consists of two distinct sets of entities (Figure 1): Mobile Clients (MCs) and fixed hosts. Some of the fixed hosts,called Mobile Support Stations (MSSs), are enhanced with wireless interfaces. An MSS can communicate with the MCs within its radio coverage area

called wireless cell. An MC can communicate with a fixed host/server via an MSS over a wireless channel. The wireless channel is logically separated into two sub-channels: an uplink channel and a downlink channel. The uplink channel is used by MCs tosubmit queries to the server via an MSS, whereas the downlink channel is used by MSSs to disseminate information or to for-

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60 Int. J. of Information Technology and Web Engineering, 1(1), 59-75, January-March 2006

Figure 1. Mobile computingmodel

IS F ix e d n e tw o rk IS
2

1

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M o b ile su p p o rt sta tio n

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M o b ile clien t

W ireless cell

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In fo rm atio n server

ward the responses from the server to a target client. Each cell has an identifier (CID) for identification purposes. A CID is periodically broadcasted to all the MCs residing in a corresponding cell. A wireless mobile application isdefined as a software application, a wireless service or a mobile service that can be either pushed to users’ handheld wireless devices or downloaded and installed, over the air, on these devices.1 Such applications must work within the daunting constraints of the devices themselves:

als, an asterisk (*), and a pound sign (#).

• Screen: The display might be as small
as 96 pixels wide by 54pixels high and 1 bit deep (black and white). The amount of information that can be squeezed into such a tight screen is severely limited. In addition, the wireless environment imposes further constraints: (1) wireless networks are unreliable and expensive, and bandwidth is low; (2) they tend to experience more network errors than wired networks; and (3) the very mobility of wireless devices...