Smart Cards in Telecommunications
Telecommunications, or communications technology, is the technology used to exchange messages over arbitrary distances between persons and/or machines. Over the centuries, it has developed from human messengers and visual signaling techniques to communications using wire-bound and wireless electrical signals. The pioneers in this field were primarily military organizations and businessmen, for whom it was a matter of survival to be able to transmit messages as quickly as possible. Nevertheless, the biggest impetus to the development of telecommunications has come only in recent years, during which it has become a true mass application as the result of various favorable conditions, such as deregulation of the market, inexpensive manufacturing of terminal equipment and a general economic and technical boom. Although the first proposals for using electricity to convey messages were published as early as 1753, the first telegraph line between Paris and Lille did not go into service until 1794. In the following decades, inventions related to conveying messages using electricity were made by numerous persons in many countries. The most important and most interesting of these developments were the construction of the electrochemical telegraph by S. Soemmerring in 1809, the invention of induction telegraphy by Carl Friedrich Gau?and Wilhelm Weber in 1833 and the construction of the recording telegraph by Samuel Morse in 1835 (along with the publication of the Morse code). However, all of these inventions and constructions, many of which were quite sophisticated, could only transmit coded electrical signals, rather than the human voice. The latter first became possible around 1860. As so often with major inventions, it is not possible to credit a single person with the invention of the telephone. Still, there were essentially two personswhopublicly demonstrated devices that could transmit speech1 using electrical signals: Johann Philip Reis, a teacher at a school for the deaf, and Alexander Graham Bell, a teacher of the deaf and dumb. Both of them originally conceived their inventions as teaching aids for helping deaf persons learn to speak. The major strength of Alexander Graham Bell was his aggressive marketing of his invention, with the result that he came to be the better known of the two inventors of the telephone.

The first local telephone network was constructed in 1878 in New Haven in the USA. In Berlin, the first local public telephone network was put into operation in 1881. It had human operators, and naturally it had all the characteristics of the simple electronic technology of the time. However, the first automatic telephone exchange in Germany, using rotary lifting selector switches, was installed as early as 1908 in Hildesheim. The worldwide installation and interconnection of what is known in technical terms as the ‘public switched telephone network’ (PSTN) began at this date. After Guglielmo Marconi succeeded in making the first wireless transmission of data over a distance of several kilometers in 1896, it took only five years for the Atlantic Ocean to be bridged by wireless telegraphy. The invention of amplifier tubes (valves) stimulated the technical development of transmitters and receivers for voice communications, with the result that the first successful transmission of speech over the Atlantic Ocean took place in 1915. At the 1929 radio exhibition in Berlin, the first ‘picture phone’ was presented. It had the dimensions of three contemporary telephone booths. In the following years, the technical development of telecommunications and mobile radios accelerated, leading to the inauguration of the first mobile telecommunications network at a relatively early date. The first public land mobile networks (PLMNs) came into being around 1950, and at that time they were reserved for a small and primarily well-to-do social class. For instance, the first public mobile telephone network in Germany (the A-Netz) started operation in 1958. It had human operators and used analog signals in the 150MHz band.With a geographic coverage of approximately 80%of the Federal Republic of Germany, it had a maximum capacity of 10,500 subscribers. This first mobile telephone network in Germany did not have a cellular architecture, but instead consisted of a few distributed high-power transmitter and receiver facilities within whose coverage area it was possible to make telephone calls. It was also necessary to know the approximate location of the mobile telephone subscriber when placing a call to the subscriber, so that the proper radio zone could be selected by the human operator. The A-Netz remained in operation until 1977, when it was replaced by the B-Netz and subsequently the C-Netz, both of which are also analog systems.

At the beginning of the 1980s, mobile telephone networks with cellular architectures simultaneously came into being in many parts of the world. However, these systems were all mutually incompatible, and due to the expense of the terminal equipment (mobile telephones) and high usage charges, they were only suitable for a relatively well-to-do clientele. These networks are presently referred to as the first-generation (1G) mobile telecommunications networks. They were cell-based, but data transmission at the ‘air interface’ was still analog. Subscribers were identified by personalized mobile telephones, which means that each mobile telephone had a fixed association with a particular subscriber. One of the first 1G systems, the German C-Netz (which is also designated C-450), supported the use of cards. Magnetic-stripe cards were still used in the first C-Netz mobile telephones, but they were quickly supplanted by smart cards. This led to a distinction between the telephone and the subscriber, with the result that the personalization of telephones, which was standard at that time, was no longer necessary. As a consequence, the telephones, which are quite expensive compared with the smart cards, became readily interchangeable. Due to strong competition, the prices of mobile telephones decreased rapidly, which was in the interest of network operators with regard to having the largest possible potential market. The heterogeneous first-generation mobile telecommunication systems in Europe ultimately led to a desire among European postal authorities in the early 1980s to unify the many different country-specific systems. The intention behind this was to make it technically possible to use mobile telephones in more than one country, which above all would allow the prices of system components and terminals for a common European system to be drastically reduced as the result of economies of scale. The end result of several years of work was a specification for the international Global System for Mobile Communications (GSM).3 The first GSM systems underwent trials in 1991 and were put into regular service in 1992, and they have quickly spread far beyond their original European boundaries. However, in many parts of the world there are still other types of mobile telecommunication systems that are incompatible with GSM. Consequently, as early as 1985 the International Telecommunications Union (ITU) [ITU], with an eye to the future, started working on the international unification and functional extension of all existing mobile telecommunication systems. This concept was called ‘Future Public Land Mobile Telecommunication Service’ (FPLMTS). However, it failed to produce an internationally standardized solution, as was originally intended, so in 1995 it was converted into the IMT-2000 concept (‘International Mobile Telecommunication at 2000 MHz’). IMT-2000 provides considerably more room for maneuvering with regard to implementation, and it has come to form the basis for the current UMTS and other third-generation mobile telecommunication systems.

It is common throughout theworld to classify the technology of mobile telecommunications networks using a generation number. The generations are counted starting at ‘1’, and they include only networks with cellular architectures. According to this scheme, early examples of mobile telecommunication networks, such as the German A-Netz and B-Netz, would belong to generation zero, but this designation is not commonly used. The designation ‘first generation’ (abbreviated as ‘1G’) is applied to cellular mobile telecommunication networks with analog air interfaces. Some typical examples of 1G networks are AMPS and the German C-Netz. A second-generation (2G) system is understood to be a cellular mobile telecommunication network with digital data transmission on the air interface. The two most widely used 2G systems are GSM and CDMA. Functional extensions of GSM, such as the General Packet Radio System (GPRS) and EDGE (‘Enhanced Data Rates for GSM and TDMA Evolution’), which head in the direction of the third generation, are typically referred to as 2.5G systems. The third generation (3G) also encompasses cellular mobile telecommunication networks with digital air interfaces, but with major extensions with regard to mobile data communications and Internet-compatible services compared with 2G systems. Some typical 3G systems are UMTS and CDMA 2000. Both of these systems are in turn members of the IMT-2000 family. Details relevant to smart cards with regard to setting up GSM and UMTS mobile telecommunication systems are described in the sections of this chapter that are dedicated to these two systems. The first efforts to develop concepts for the fourth generation (4G) of mobile telecommunication networks are presently underway. Future telecommunication systems will doubtless have significantly greater bandwidth efficiency than present systems, since frequency spectra are a limited resource, as well as being a very expensive resource in some countries due to the way in which they are auctioned. In the GSM system, a frequency bandwidth of approximately 5 Hz is required for a transmission bandwidth of 1 bit/s, resulting in a frequency efficiency of 0.2 bit/s per Hz. In the UMTS system, this is already improved to 1 bit/s per Hz, and in systems still in the research stage, efficiencies of up to 30 bit/s per Hz have already been achieved. There are many additional ideas and proposals for 4G systems, although none of them have yet achieved a confirmed status or a uniform development direction. Nevertheless, the basic features of the two main constraints have already been established: international interoperability of the terminal devices and high data transmission rates as needed. Interestingly enough, these two desires were already stated in the mid-1980s as major requirements for FPLMTS and IMT-2000.