The Global System for Mobile communications (GSM) is a second generation cellular telecommunication system which was first planned in the early 1980s. Unlike first generation systems operating at the time, GSM was digital and thus introduced greater enhancements such as security, capacity, quality and the ability to support integrated services. Initially, GSM was planned to be a European system allowing subscribers to roam between different networks however, GSM was quickly adopted by many other regions and is now a Global System. Many countries around the world have now met market saturation point, which means over 100% of the population of that country possess a GSM phone. The spectrum range for the GSM1900 operation is between 1850MHz and 1910MHz for uplink operation and 1930MHz and 1990MHz for downlink operation. GSM1900 is also known as PCS (Personal Communication System) 1900.