Pri načrtovanju ali modifikaciji sodobnih mobilnih radijskih omrežij se srečujemo z dilemo, kateri program oziroma kateri model za napovedovanje širjenja radijskega signala uporabiti. Srečujemo se z množico modelov slabljenja, ki nam jih servirajo računalniški programi za izračune pokritosti z radijskim signalom.
V zaključni nalogi je poudarek predvsem na frekvenčnih področjih VHF in UHF. V prvem delu so povzete osnovne fizikalne značilnosti širjenja elektro magnetnega valovanja ter vpliv zemeljskega površja glede na geografske in strukturne značilnosti tal. Sledi temeljita analiza izračunov številnih modelov za napovedovanje širjenja radijskega valovanja.
Štirje modeli, ki so bodisi v literaturi ali v praksi največkrat uporabljeni, so v sklopu zaključne naloge podvrženi temeljiti primerjavi s terenskimi meritvami. Meritve so bile opravljene v frekvenčnih področjih VHF in UHF, na 40 km dolgem testnem poligonu v Ljubljani in njeni okolici.
Izračuni napovedi jakosti polja so izvedeni s pomočjo računalniškega programa TAP SoftWright. Radijski del na strani oddajne in sprejemne radijske postaje je zajemala oprema proizvajalca Motorola. Za hkraten prenos zajetih veličin s sprejemne radijske postaje pa je skrbel računalniški program Mototrbo Site Survey.
Na razgibanem testnem poligonu so bile ugotovljene prednosti in slabosti posameznega modela za napovedovanje širjenja radijskega signala. Nekaj dvoumnih tez pa je bilo dokončno potrjenih šele z dodatnimi meritvami in izračuni na podlagi drugega pomožnega testnega poligona.
| Language: | English |
|---|
| Title: | Methods for predicting modern mobile radio network coverage |
|---|
| Abstract: |
|---|
While planning or modifying modern mobile radio networks, there exists some doubt regarding which program and propagation model should be used. There are many propagation models recommended by computer programs to design and analyze wireless communication systems.
The thesis centres on the VHF and UHF frequency bands. First part contains the fundamental physical characteristics of VHF and UHF propagation and the influence the geographic and structural features of terrain. The first part is followed by an analysis of different propagation models.
The four most frequently used propagation models are compared based on measurements in the VHF and UHF frequency bands in a 40 km long primary test route in Ljubljana and its surroundings.
Predicted calculations of signal strength are implemented by computer software TAP SoftWright. Radio part includes transmit base station and receive mobile radio station from Motorola Solutions. Software Mototrbo Site Survey was used to simultaneously transfer the data gathered from the receiving radio station.
The advantages and disadvantages of each tested model have been determined based on the measurements from the dynamic test route. Finally, some dubious hypotheses were confirmed using additional measurements from the secondary test route.
|
| Keywords: | propagation model, VHF, UHF, signal attenuation, radio wave, Egli, Okumura, Hata-Davidson, Longley-Rice, Tap, SoftWright, Motorola, … |
|---|
