This book offers students scientists and engineers an extensive introduction to the
theoretical fundamentals of digital communications covering single input single output (SISO)
multiple input multiple output (MIMO) and time-variant systems. Further the main content is
supplemented by a wealth of representative examples and computer simulations. The book is
divided into three parts the first of which addresses the principles of wire-line and wireless
digital transmission over SISO links. Digital modulation intersymbol interference and various
detection methods are discussed models for realistic time-variant wireless channels are
introduced and the equivalent time-variant baseband system model is derived. Since not all
readers may be familiar with this topic Part II is devoted to the theory of linear
time-variant systems. The generalized convolution is derived and readers are introduced to
impulse response the delay spread function and system functions in the frequency domain. In
addition randomly changing systems are discussed. In turn Part III deals with MIMO systems.
It describes MIMO channel models with and without spatial correlation including the Kronecker
model. Both linear and nonlinear MIMO receivers are investigated. The question of how many bits
per channel use can be transmitted is answered and maximizing channel capacity is addressed.
Principles of space-time coding are outlined in order to improve transmission quality and
increase data rates. In closing the book describes multi-user MIMO schemes which reduce
interference when multiple users in the same area transmit their signals in the same time slots
and frequency bands.
