Mobile Communications

Brief summary

The book  »Mobile Communication«  deals with the essential differences compared to systems for the fixed network,  when transmitters and/or receivers are moving.  Thus,  intersymbol interference is not caused by frequency dependence of the medium »electrical line« or »optical fiber»,  but by multipath propagation due to reflections,  resulting in constructive or destructive superpositions of the electromagnetic wave with its echoes.  Here are some of the topics covered:

1. Time-variant transmission channels:  Distance-dependent attenuation,  shadowing,  Rayleigh fading  $($at line-of-sight$)$,  Rice fading  $($without line-of-sight$)$.
2. Frequency-selective transmission channels:  Two-dimensional impulse response and transfer function,  multipath reception in mobile radio,  GWSSUS model.
3. Second and third generation mobile radio systems:  Characteristics of GSM  $\rm (2G)$  and UMTS  $\rm (3G)$,  Similarities between the two, further developments.
4. The 4G–LTE mobile standard  $($"Long Term Evolution"$)$,  similarities and differences between  "OFDMA"  $($e.g.  at DSL$)$  and  "OFDMA"  $($e.g. at LTE$)$.

Notes:

• Many of the fundamentals covered in the book  »Signal Representation«  are still valid.  Differences arise from the radio channel,  which is mostly time-varying.

• More detailed descriptions of second and third generation mobile radio systems  $($GSM,  UMTS$)$  can be found in the book  »Examples of Communication Systems».

• It should be noted,  however,  that their importance today  $($2023$)$  is no longer very great;  in some countries GSM and UMTS have already been switched off.

⇒   Here first a  »contents overview«  based on the  »four main chapters«  with a total of  »sixteen individual chapters«  and  »121 sections«.

Content

Time-Variant Transmission Channels

• Distance Dependent Attenuation and Shading
• Probability Density of Rayleigh Fading
• Statistical Bindings within the Rayleigh Process
• Non-Frequency-Selective Fading With Direct Component

Frequency-Selective Transmission Channels

• General Description of Time Variant Systems
• Multi-Path Reception in Mobile Communications
• The GWSSUS Channel Model

Mobile Radio Systems of the 2nd and 3rd Generation - an Overview

• History and Development of Mobile Communication Systems
• Similarities between GSM and UMTS
• Characteristics of GSM
• Characteristics of UMTS

LTE – Long Term Evolution

• General Information on the LTE Mobile Communications Standard
• Technical Innovations of LTE
• The Application of OFDMA and SC-FDMA in LTE
• Physical Layer for LTE
• LTE-Advanced - a Further Development of LTE

Exercises and multimedia

In addition to these theory pages,  we also offer exercises and multimedia modules on this topic,  which could help to clarify the teaching material:

$(1)$    $\text{Exercises}$

$(2)$    $\text{Learning videos}$

$(3)$    $\text{Applets}$ 

Further links

$(4)$    $\text{Bibliography}$

$(5)$    $\text{Impressum}$