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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> | | 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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Revision as of 19:38, 21 September 2014
Building .... Networks
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History, Now and Future
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History
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Pioneers: Maxwell, Hertz,...
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1G, 2G,... 5G networks
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Frequencies and Standards
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Future Challenges
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A-Basics of Communication
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Electromagnetic Signals
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Radio Communication Principles
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Digital communication: Signal/Noise Ratio
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Signal strength and Capacity: Shannon
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B-Antennas and Propagation
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Free Space Propagation
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Antennas, Gain, Radiation Pattern
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Multipath Propagation, Reflection, Diffraction
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Attenuation, Scattering
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Interference and Fading (Rayleigh, Rician, …)
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Mobile Communication dependencies
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C-Propagation models
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Environments (indoor, outdoor to indoor, vehicular)
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Outdoor (Lee, Okumura, Hata, COST231 models)
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Indoor (One-slope, multiwall, linear attenuation)
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D-System Comparison
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Proximity: RFID, NFC
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Short Range: ZigBee, Bluetooth, ANT+,...
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WLAN/Wifi/802.11...
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Mobile: GSM, UMTS, IMT-A (WiMAX, LTE)
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E-Mobility
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Mobile Network mobility
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IP mobility
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F-Network Building
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5G and Future Networks
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5G Heterogeneous Networks
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Basic Internet
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Video Distribution Networks
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Coverage simulations
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Coverage simulations
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Traffic simulations
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Network Capacity simulations
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Building .... Networks
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⌘Multipath and how to use it
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Multipath propagation can be used through
- ) specific receivers (rake receivers)
- ) Multiple-input, multiple-output antenna systems (MIMO)
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Note: The mobile phone users will typically not have a direct link between the mobile phone and the antennas of the base station in a typical environment. Such a situation, where the mobile communication has to go "around a building" or "around the corner" are called NLOS, non Line-of-Sight connection. As compared to a Line-of-Sight LOS connection the signal is typically reduced by some 20-30 dB.
⌘ Boundary conditions
- What is happening on electrical walls, magnetic walls?
Scattering, reflection and diffraction (explain differences) are the three major components in wave propagation. Ideal reflection environments are characterised through
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Receiver characteristics for usage of reflections in impulse response
- sliding 16 mu s window and integration of power in this window (typical GSM)
- Rake receiver, where each finger of the receiver points to one reflection (typical enhanced GSM, UMTS)
- MIMO (Multiple input, multiple output) or smart antenna arrays. Here we use spatial filtering, assuming that radiation comes in from different directions (typical 802.11n, smart antennas for UMTS)
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⌘ Reflection
Reflection at a perfectly plane gives a reflection coefficient r= -1. When the surface gets rougher, reflection is still in the main direction, but the reflected power is spread around the main reflection angle. Assuming that no absorption takes place, then the total reflected power is constant.
When the surface becomes extremely rough, and with roughness >> lambda, then the reflected wave will be scattered into any direction.
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Related physics
Free Space impedance
as connection of permeability
and permittivity
.
. The unit of
is
. The unit of
is Farad/m: