Theory of linear systems and signals (in particular Fourier transform), basics of digital (linear) modulation schemes (PSK, QAM) and corresponding pulse shapes (square-root cosine pulses), probability theory, basics of stochastic processes, in particular Gaussian processes. These topics are presented in the lectures "Communications" and "Signals and Systems".
Learning target: To acquire theoretical and practical understanding of the physical layer of wireless communication systems with mobile users. Ability to design and assess transmission concepts for mobile communication systems. Content: First, a survey of concepts of various mobile communication systems is given. The systems are classified according to different criteria. In the following, the principles of mobile communications are discussed, which are applicable to any wireless communication system. In particular, these are the mathematical description of time-variant radio channels using stochastic processes, diversity principles in order to combat fast fading, multiplexing schemes, duplexing schemes, modulation (e.g. Gaussian minimum-shift keying, GMSK), and channel coding with special consideration of the need for interleaving. Especially, the interaction of channel coding, interleaving and slow frequency hopping as applied in GSM as countermeasure against fast fading is analyzed. Receiver algorithms for channels with intersymbol interference are briefly addressed. The cellular concept of large systems like GSM and UMTS is introduced.