Evolution of GSM into the Next Generation Wireless World

GSM is the most widely deployed 2^nd generation digital cellular standard, with over 2 billion subscribers in some 213 countries and adding about 1000 new users per minute! Originally developed in the 1980s, and first deployed in 1991, GSM is a TDMA+FDMA system, providing wide area voice communications using 200 KHz carriers. Subsequently, GSM evolved into a 2.5G standard with the introduction of packet data transmission technology (GPRS) and higher data rates via higher order modulation schemes (EDGE). More recently, GERAN standards organization has been evolving further to coexist with and provide comparable services to 3G technologies. In this paper, we first provide an overview of the traditional 2G and 2.5G GSM, and then discuss the so-called "GERAN Evolution" into the 3G world. We conclude by detailing a few selected aspects of the GERAN Evolution. Overall, we aspire to demonstrate that GERAN is a vibrant, living and growing technology that exploits the latest advances in communications and signal processing.