Informationen zur Lehrveranstaltung:
Mobile Communications
Neue wahlobligatorische Lehrveranstaltung für die Studiengänge Weitere Interessenten sind herzlich willkommen.



Ort und Zeit:




This lecture provides an introduction to mobile communication systems with a focus on the physical layer. It is given in English to familiarize the students with the linguistic requirements of a global economy, where technical discussions between international partners are usually conducted in English. Moreover, the students have the opportunity to participate in projects, where they get to know international research papers about this exciting topic.


Homework assignments will be given to you as the semester progresses. Most homework problems will be to show some results discussed in class. This will involve theoretical proofs as well as simulation studies using Matlab. In many cases, assignments can involve examining the performance of a system or extracting key parameters from measurements. Most of the topics covered by the course is best learned by working with the problems through a combination of computer simulations and theoretical analysis. The homework is therefore one of the most important parts of the course.

Cooperative group study on the homework is encouraged, but simply copying someone else's work is unethical and will leave you unprepared for exams. Significant insight can be gained by studying with another student or in a group, provided you discipline yourself to find your own solutions first before comparing results. Rely on other's help only when you have exhausted all of your own ideas or have made no progress for an extended period of time.

Homeworks for Sommersemester 2017:


Updated 03.07.2017

Sample exams:

2010, Summer semester: PDF

Student Projects:

The offered student projects are available at the Hauptseminar Mobile Communications page

- complete: slides with the numbers used in the lectures
- compact: file without additional slides, therefore different numbers

Written Exam:


1 Introduction
  + Overview of mobile communication standards and applications (1G - 5G)
  + 5G Vision and Requirements
  + The Wireless Channel
    - Path loss
    - Shadowing
    - Fast fading
2 Mobile Communication Channels
  + Review: Representation of Bandpass Signals and Systems
2.1 Propagation Modelling
  + Time variance (Doppler)
  + Time-varying multipath channels
    - Transmission functions of the time-varying channel (1st set of Bello functions)
    - 4 ways to calculate the received signals
    - Identification of linear time-varing (LTV) systems
2.2 Statistical Characterization of Multipath Channels
  + Rayleigh channel (fading)
  + Rician channel
  + Channel Correlation Functions and Power Spectra of Fading Multipath Channels
    - Time-variations of the channel
    - Characterization of a WSSUS channel (2nd set of Bello functions)
2.3 The effect of signal characteristics on the choice of a channel model
  + Frequency non-selective channels
  + Frequency selective channels
    - Truncated tapped delay line model of a frequency selective channel
2.4 Space-Time Channel and Signal Models
  + Generalization of the time-varying channel impulse response
    - First set of Bello functions extended to the spatial domain
    - Example: specular L paths model (continued)
  + Homogeneous channels (WSSUS-HO model)
  + Correlation functions and power spectra extended to the spatial domain
    - Second set of Bello functions extended to the spatial domain
    - Coherence time, coherence frequency, coherence distance
  + Transmission functions extended to transmit and receive antenna arrays (MIMO)
    - Definition of the array manifold
  + Notation for SISO, SIMO, MISO, and MIMO channels
    - Example: L paths model (continued)
  + Classical IID Channel Model
  + Extended MIMO Channel Models
    - Spatial fading correlation at the transmit and the receive arrays
      > Review of the eigenvalue decomposition (EVD)
      > General model
      > Kronecker model
    - Additional Line-of-Sight (LOS) component
  + Sampled signal model for SISO, SIMO, MISO, and MIMO channels
3 Capacity of Space-Time Channels
3.1 Differential Entropy and Mutual Information for Continuous Ensembles (review)
3.2 Capacity Theorem for the AWGN SISO Case (review)
3.3 Capacity of the Flat Fading MIMO channel
  + Differential entropy for CSCG random vectors
  + Choosing Rss (with and without CSI @ the transmitter)
    - Singular Value Decomposition (SVD)
    - Special case: uncorrelated Rayleigh fading and Mt very large
  + Parallel Spatial Sub-Channels
    - Design of the precoder and the decoder for MIMO systems with CSI at the transmitter
    - Optimum power allocation (waterpouring algorithm) with CSI at the transmitter
  + SIMO Channel Capacity
  + MISO Channel Capacity
  + Capacity of Random MIMO Channels
    - Ergodic vs. non-ergodic channels
    - Ergodic capacity
      > Examples, e.g., Rice, correlation
    - Outage capacity
3.4 Capacity of the Frequency Selective MIMO channel
  + Space-Frequency Waterpouring
4 Transmission Techniques
4.1 Bit error probability
  + Binary signaling over Rayleigh fading channel
4.2 Diversity techniques for fading multipath channels
  + Frequency diversity
  + Time diversity
  + Space diversity
  + Post-processing techniques
    - Selection combining, equal gain combining, maximum ratio combining, square-law combining
4.3 Approximation of the Probability of Symbol Error
  + Fading channel with D-fold diversity
  + Chernoff bound
  + Coding gain vs. diversity gain
5 Space-Time Processing
5.1 Receive antenna diversity (SIMO channel): MRC
5.2 Transmit antenna diversity
  + MISO channel unknown to the transmitter: Alamouti scheme (1998)
  + MISO channel known to the transmitter: MRT
  + MIMO channel unknown to the transmitter: Alamouti scheme (1998)
  + MIMO channel known to the transmitter: DET
  + Definiton of the effective diversity order
  + Summary: Diversity of space-time-frequency selective channels
5.3 Space-Time Coding without channel state information (CSI) at the transmitter
  + Space-Time Coding for frequency flat channels
  + Space-Time codeword design criteria
    - definition of the pairwise error probability (PEP)
    - rank criterion
    - determinant criterion
  + Orthogonal Space-Time Block Codes (OSTBCs)
    - OSTBCs for real-valued constellations
    - OSTBCs for complex-valued constellations
  + Spatial Multiplexing (SM) as a Space-Time Code
  + Encoder Structures for Spatial Multiplexing (SM)
    - horizontal encoding
    - vertical encoding
    - diagonal encoding (D-BLAST transmission)
5.4 Gains achievable with smart antennas
  + Array Gain
  + Diversity Gain
  + Spatial Multiplexing Gain
  + Interference Reduction Gain
    - frequency reuse and cluster sizes
5.5 Multi-User MIMO Systems
  + Block Diagonalization
5.6 Multiple access schemes
  + OFDM
  + Single carrier vs. OFDM vs. spread spectrum


last change 2017-07-03, Impressum

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