|
Kategorie: Diplomové, bakalářské práce |
Tento dokument chci!
Tato práce zkoumá vhodnost a požadavky návrhu simulací pro simulátor NS-3 pro případ bezdrátových sítí používaných v měřící infrastruktuře společnosti Kamstrup. V práci jepopsán simulátor NS-3 a je vytvořena základní implementace dvou protokolů. WirelessM-Bus jako příklad jednosměrného protokolu pro zařízení napájené z baterií. Simulace Wireless M-Bus je porovnána s daty naměřenými v reálném systému. NS-3 poskytuje flexibilní prostředí pro vývoj simulací různých síťových protokolů, včetně těch určených pro sítě inteligentních měřidel.
There even more uncertainty for the meters
propagation losses, the signal can attenuated penetration loss walls and
ceilings etc.
3. Such exported data
could used assess different propagation models other tools, e.
25
.g. zero mean Gaussian random variable
(in dB) which represents the local shadowing that assumed log-normally
distributed.
10 log
4π 868. (3. Nevertheless, remains a
viable future improvement.
A log-distance propagation model was chosen, because quite simple, yet can
give satisfactory results and has implementation NS-3.
The propagation model was first tested using Matlab script.
However, while the direction and gain the concentrators known, there are less
data about the orientation the repeaters and meters, therefore omnidirectional
gain pattern assumed.22 dB, i.3.97, which was result fitting
the data, and PL(d0) 31. the other
hand, there are not that many repeaters the data set.3 Log-distance Propagation Model
The first and simplest model investigated was the log-distance path loss model, that
can defined the following equation (in dB) [8]:
PL(d) PL(d0) 10n log(d/d0) (3. addition to
the loaded data, approximation the concentrator antenna pattern was created
based its datasheet. the free-space propagation loss m
for frequency 868 MHz.
The data were then used find the appropriate parameters the log-distance
model.orientation, well respective received power information.
Eventually, the simulations were run with 2.95 106
3 108
2
= 31.3)
Where PL(d) the path loss the distance PL(d0) the known path loss at
the reference distance d0, usually the free space propagation loss 100 1
km used.4)
The model could improved using knowledge about repeaters.22 dB. Matlab. However, turned out that the model fits better when the antenna pattern
of the concentrators assumed isotropic gain. The parameter describes the relation between the distance and path
loss and depends the environment.e
