The following will be discussed in this chapter: Radiation pattern, parabolic reflective antenna, antenna gain, signal loss in satellite communication, noise types, refraction, fading, diffraction and scattering, fast and slow fading, flat and selective fading, diversity techniques. | Cellular Wireless Networks GSM Lecture 30 Development of Mobile Systems 2 What is GSM? GSM, the Global System for Mobile Communications, is a digital cellular communications system GSM provides – Digital Transmission ISDN compatibility Worldwide roaming in other GSM networks Provides a model for 3G Cellular systems (UMTS) 3 GSM Overview GSM formerly: Groupe Spéciale Mobile (founded 1982) now: Global System for Mobile Communication Pan-European standard (ETSI, European Telecommunications Standardisation Institute) simultaneous introduction of essential services in three phases (1991, 1994, 1996) by the European telecommunication administrations (Germany: D1 and D2) seamless roaming within Europe possible Today many providers all over the world use GSM (>220 countries in Asia, Africa, Europe, Australia, America) more than 4,2 billion subscribers in more than 700 networks more than 75% of all digital mobile phones use GSM 4 Performance Characteristics of GSM Communication mobile, wireless communication; support for voice and data services Total mobility international access, chip-card enables use of access points of different providers Worldwide connectivity one number, the network handles localization High capacity better frequency efficiency, smaller cells, more customers per cell High transmission quality high audio quality and reliability for wireless, uninterrupted phone calls at higher speeds (., from cars, trains) Security functions access control, authentication via chip-card and PIN 5 Disadvantages of GSM There is no perfect system!! no end-to-end encryption of user data no full ISDN bandwidth of 64 kbit/s to the user, no transparent B-channel reduced concentration while driving electromagnetic radiation abuse of private data possible roaming profiles accessible high complexity of the system several incompatibilities within the GSM standards 6 GSM: Mobile Services GSM offers several types of connections voice connections, data connections, short message | Cellular Wireless Networks GSM Lecture 30 Development of Mobile Systems 2 What is GSM? GSM, the Global System for Mobile Communications, is a digital cellular communications system GSM provides – Digital Transmission ISDN compatibility Worldwide roaming in other GSM networks Provides a model for 3G Cellular systems (UMTS) 3 GSM Overview GSM formerly: Groupe Spéciale Mobile (founded 1982) now: Global System for Mobile Communication Pan-European standard (ETSI, European Telecommunications Standardisation Institute) simultaneous introduction of essential services in three phases (1991, 1994, 1996) by the European telecommunication administrations (Germany: D1 and D2) seamless roaming within Europe possible Today many providers all over the world use GSM (>220 countries in Asia, Africa, Europe, Australia, America) more than 4,2 billion subscribers in more than 700 networks more than 75% of all digital mobile phones use GSM 4 Performance Characteristics of GSM Communication mobile, .
