The demand for portable electronic consumer products is rapidly increasing.
Examples of fast-growing markets of portable products are notebook computers,
cellular and cordless phones and camcorders. Figure 1.1 shows the expected worldwide
shipment of cellular handsets until the year 2004 [1], with the total number of
handsets sold increasing dramatically. At present, almost half of the shipments of
cellular handsets are replacement sales, which means that people who already have a
cellular phone buy them. By 2004, almost all cellular handsets sold will be
replacement sales.