Difference between revisions of "Basics of Communication (A1-A3)"

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{{:Building Networks/Digital Communication principles}}
 
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=⌘ Boundary conditions =
 
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* What is happening on electrical walls, magnetic walls?
 
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[[File:DirectReflectedWave.png|450px|right|Figure: Reflection of an electromagnetic wave at the ground plane]]
 
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Scattering, reflection and diffraction (<span style="color:#000B80">explain differences</span>) are the three major components in wave propagation. Ideal reflection environments are characterised through <math>  |r| =1,\ \ \phi_r=180\deg </math>
 
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[[File:UMTScells.png|450px|right|Figure: UMTS macro and microcells in a 6-operator environment]]
 
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=⌘  Nyquist Theorem  =
 
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[[File:BandlimitedSignals.png|450px|right]]
 
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* Shannon: If a function <math>f(t) </math> contains no frequencies higher than <math>W </math> [cycles/s], it is completely determined by giving its ordinates at series of points spaced <math>\frac{1}{2W} </math> seconds apart
 
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[[File:InsufficientlySampled.png|450px|right]]
 
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* <span style="color:#000B80"> band-limitation versus time-limitation
 
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* <span style="color:#000B80"> Fourier transform
 
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[source: Shannon, 1948]
 
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=⌘  Signal/noise ratio  =
 
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<math>\mathrm{SNR} = {P_\mathrm{signal} \over P_\mathrm{noise}} </math>
 
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<math>\mathrm{SNR (dB)} = 10 \log_{10} \left ( {P_\mathrm{signal} \over P_\mathrm{noise}} \right ) </math>,
 
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where ''P'' is average power
 
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* <span style="color:#000B80"> why talking about noise?</span>
 
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* <span style="color:#000B80"> dB, <math>\mbox{dB}_m,\ \mbox{dB}_a </math></span>
 
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* <span style="color:#000B80"> near-far problem</span>
 
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[source: Wikipedia]
 
  
  

Revision as of 10:32, 21 September 2014

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Basics of Communication (A1-A3)

Course UNIK4700, UNIK9700
Title Basics of Communication and Assignments
Lecture date 2014/09/05 0900-1200 h
presented by Josef Noll
Objective The objective of this lecture is to explain the principles of radio communication
Learning outcomes What will we learn today
  • Basics of radio communication
  • Typical radio transmission
  • What effects the signal strengths
Pensum (read before) Read before:
References (further info) References:

A Practical Evaluation of Radio Signal Strength:

Propagation characteristics of wireless channels:

Keywords SNR, Transmit Power, Scattering, Reflection, Diffraction

this page was created by Special:FormEdit/Lecture, and can be edited by Special:FormEdit/Lecture/Basics of Communication (A1-A3).


Test yourself, answer these questions

  • What factors affect Wireless signal strength?
  • Explain the meaning of the term diffraction
  • How is diffraction used for radio communications?
  • What is the difference between diffraction and interference?
  • What is the difference between Scattering and Diffraction?
  • What is non line of sight (NLOS)?
  • Does WiMAX possess NLOS capability?
  • How is UMTS different from current second generation networks?

Lecture notes

earlier notes


To Do

Towards next lecture:

  • Select papers related to your topics
  • Come with a suggestion on the direction of your presentation
  • Josef to define a time schedule
  • No assignment, talk to Josef!


Test yourself, answer these questions

  • What factors affect Wireless signal strength?
  • Explain the meaning of the term diffraction
  • How is diffraction used for radio communications?
  • What is the difference between diffraction and interference?
  • What is the difference between Scattering and Diffraction?
  • What is non line of sight (NLOS)?
  • Does WiMAX possess NLOS capability?
  • How is UMTS different from current second generation networks?


S5-unik-preview.png
Slide Show

Title
UNIK4700/UNIK9700 Basics of Propagation
Author
Josef Noll,
Footer
Basics of Communication (A1-A3)
Subfooter
UNIK4700/UNIK9700




⌘ UNIK4700 Radio and Mobility

Lecture 2: Basics of communications

⌘ Principles of radio communication

  • radio wave propagation
  • Electromagnetic signals
  • Nyquist Theorem
  • Signal/noise ratio
  • Shannon Theorem
  • Signal strength

Building Networks/Electromagnetic signals

Building Networks/Radio Communication principles

Building Networks/Digital Communication principles


⌘ Shannon Theorem

Shannons theorem will be part of next lexture...


⌘ Summary

  • radio wave propagation explain
  • Electromagnetic signals
  • Nyquist Theorem
  • Signal/noise ratio
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