110-121 3Gstand, JM 15/9

Various digital cellular standards were developed in several regional standards bodies during the late 1980s and early 1990s. The first-generation standards had been developed some ten years earlier. GSM The development of the new pan-European digital cellular standard got under way in 1985. GSM has since evolved into the leading global second-generation standard, in terms of number of subscribers and area of coverage (Figure 2). GSM is an eight-slot, time-division multiple-access (TDMA) system with 200 kHz carrier spacing. In terms of service, GSM is mobile ISDN (integrated services digital network), with support for a wide variety of services. Intelligent network (IN) support in the mobile environment has also been defined for GSM—for example, the virtual home environment—as well as many advanced data services. And today, thanks to general packet radio services (GPRS), packet access can also be integrated into GSM.