A practical reengineering approach for mobile terminal software

Embedded devices like mobile phones are very limited in memory and developers always struggle to squeeze in as much information as possible. In most legacy mobile systems, the operating system is a simple scheduler with no complicated multi-tasking capabilities and programs are written in plain C language for efficiency purposes. A family of such embedded products is built to meet the needs of various market segments. End users are always looking for smaller and fancier devices with more features. But there is only a certain limit to which existing systems can be pushed, beyond which it becomes impractical to accommodate more features without using some advanced reengineering techniques. At Nokia Research Center, a task was assigned to reengineer existing systems to meet the needs of Third Generation Mobile Systems in an efficient manner so that more applications and operating modes could be supported. This paper presents the approach that was used to reengineer a legacy mobile phone system to meet the needs of future systems. The approach is very simple and systematic and at the same time very practical and effective. Although the domain under consideration is a mobile phone system, a similar approach can be successfully applied to other product families