A confluence of factors will converge to boost smartphone shipments at an impressive compound annual rate of 44 percent over the next five years, according to research firm In-Stat/MDR.

These numbers jibe with an earlier ABI Research report that predicted a quarter of all mobile handsets will be Symbian-based—by far the most popular smartphone operating system—by 2009. That's for a mobile phone market that topped 520 million units shipped in 2003, and should grow to over 600 million a year by the end of the decade.

By comparison, Gartner reported in the Spring that vendors sold only 10 million smartphones (6.67 million Symbian) in 2003—respectible for PDAs but tiny when compared to mobile phones.

Factors leading to smartphone growth include smaller form factors; falling prices on select devices; better integration of voice, e-mail and Personal Information Manager functions; a growing variety of devices; and increased demand from business users looking for integrated voice and data services.

Nevertheless, smartphone vendors must overcome certain obstacles before the striking sales figures mentioned above are reached: Many devices are too expensive, the costs to high, and the sizes to big. In addition, the lack of 3G networks make data services less than satisfactory, while battery life isn't up to the level consumers are used to from traditional mobile phones. Security is another concern.

In-Stat/MDR expects device manufacturers will address these issues in the next 12 to 18 months. Neil Strother, an In-Stat/MDR Senior Analyst, commented, "Most of these hurdles can, and will, be solved, and the smartphone's best days are just around the corner."