5 Software design
In this chapter, we examine the major software components of a mobile handset and the key design issues which affect their
design. The Motorola DynaTAC, the world's first portable cellular handset, first announced in 1973, required minimal software, and utilized a simple microcomputer
built with fewer than 2000 transistors. A modern smartphone, such as the iPhone 4GS, supports 16 Gbyte of flash and 256 Mbyte of RAM, and could have a billion transistors to perform all of the functions of the device. Given the range of software complexity over time, and the range of device types from a basic ultra-low-cost handset to a high-end tablet, we shall focus on core software elements which exist in various forms in all modern handsets, ...