Log‐Distance Path Loss Model
Considering Shadowing: Lognormal Model
Modeling the Time Varying Nature
• Consider mobile sender receiver pair
• Modeling received signal strength as R.V. X
• Considering probability P[X · x] (the CDF)
• Example: Rayleigh Fading Model
– No line of sight
– Exponential distributed CDF
• Example: Ricean fading model
– Dominant line of sight
– Ricean distributed CDF
Modellbildung
Ein einfaches Energiemodell
Required Transmission Power
Zero Power with Infinite Relays?
• Direct transmission
• Transmission with n relays
s t
d
Additive Constant Power Consumption
• Direct transmission
• Transmission with n relays
s t
d
Modellbildung
Vereinfachte Graphmodelle
The Wireless Network Graph
• Wireless network as a graph G=(V,E) – V = set of nodes
– E = set of node pairs which can reach each other
Example:
Which Nodes are Connected?
• N
0= environmental noise
• S
RX= received signal strength
• Correct reception above certain BER:
• For constant N
0follows correct reception iff
The Unit Disk Graph UGD(V)
• Nodes u and v connected iff |uv| ≤ R
• Example: transmission range of node u ?
u
R
Is this correct?
• Antenna radiation patterns
• Scattering, diffraction,
refraction • Multipath propagation
• Interference
• Obstacles
u
Transmission range of u looks rather like:
0 30 60 90 120 150 180 210 240 270 300 330 360 0
30 60 90 120 150 180 210 240 270 300 330 360
0 30 60 90 120 150 180 210 240 270 300 330 360
0 30 60 90 120 150 180 210 240 270 300 330 360