OverviewThe GSM system effectively uses new technologies. A set of innovative technology features demonstrate the engineering strength behind the system. The use of certain technological features is motivated by the benefit offered. The variety of technology levels is great; from small details hidden deep within the system to revolutionary new concepts at the top level of the system, visible to all users. The world is going digital. In many areas of technology, analog systems are being replaced by a modern digital alternative. One of the major improvements over first generation cellular systems is that GSM is a digital system. We'll take a closer look in this module at what it means when the system is digital and what benefits it offers. A key feature of any cellular mobile network is that multiple users can communicate without disturbing each other. In fact, the frequency band allocated for mobile communications is still limited and many efforts are made to develop systems capable of serving as many users as possible in a given band. GSM uses a combination of two distinct methods to meet these strict requirements. DigitalizationGSM is a digital system. Let's take a closer look at what this means, whether a signal is analog or digital. An analog signal basically means that the signal can have any value at any time. A good example is a traditional thermometer outside your window. The meter range is usually -40 Celsius to +40 Celsius and the reading can be anywhere between these values. In theory, if we had good eyesight, we could distinguish small, arbitrary differences in temperature. If the thermometer reading were converted to an electrical form, such as voltage, we would have an analog signal. In a mobile communications network, part of the transmission connection uses a radio link and another part uses 2 Mbit/s PCM links. Radio transmission is used between the mobile station (MS) and the base transceiver station (BTS) and the information must be adapted to be carried over 2 Mbit/s PCM transmission links throughout the rest of the network. In a mobile communications network, part of the transmission connection uses a radio link and another part uses 2Mbit/s PCM links. Radio transmission is used between the mobile station (MS) and the base transceiver station (BTS) and the information must be adapted to be carried over 2 Mbit/s PCM transmission links throughout the rest of the network..