Optično dostopovno omrežje s tehnologijo DVB-C

CULOT, SIMON (author), Batagelj, Boštjan (mentor)

Radio-frekvenčni digitalni in analogni signal, ki je do nedavnega potekal po bakrenih vodih (koaksialnih kablih) se danes vedno bolj nadomešča s prenosom z optičnimi kabli. Prednosti optičnega dostopovnega omrežja se pokažejo predvsem pri dometu, kvaliteti in zmogljivosti prenosa informacij. Domet zagotavlja nizko slabljenje optičnega vodnika, ustrezen vir svetlobe in optični detektor. Kvaliteta prenosa preko optičnega vlakna je bistveno večja zaradi tega, ker je optično vlakno dielektrik, to pomeni, da elektromagnetne motnje (udar strele, presluh med posameznimi steklenimi vodniki) ne vplivajo na signal. Zmogljivost optičnega vlakna se kaže v nekaj 10 THz pasovne širine, ki jo ima optično vlakno na razpolago in ki jo je mogoče uporabiti v komunikacijske namene. S tega stališča je optično vlakno najbolj širokopasovni medij. V diplomskem delu je obravnavano optično dostopovno omrežje s tehnologijo DVB-C, pri čemer se bomo osredotočili na dve arhitekturi. Prva je DVBC- P2P, ki predstavlja direktno optično povezavo med modemom pri uporabniku in glavno centralo. Druga arhitektura pa je DVBC- GPON, pri katerem je eno vlakno, preko optičnega delilnika, povezano z več uporabniki. V praktičnem delu naloge bo podrobneje predstavljena izvedba optičnega omrežja, in sicer spajanje optičnih vlaken z zlitim spojem ali konektorji, pripravo optične spojke za zaščito varov, meritve slabljenja, pripravo signalov iz različnih virov, pretvorbo signalov iz RF v optično omrežje in nazaj ter ojačenje optičnega signala. S tem bomo predstavili bistvene značilnosti kvalitetnega prenosa DVB-C signala do končnega uporabnika z uporabo dveh različnih arhitektur, kar je tudi glavni cilj našega diplomskega dela. Izzivi, s katerimi smo se soočali pri praktičnem delu naloge so bili vezani predvsem na načrt za zgraditev omrežja, zagotovitev opreme za varjenje in meritve ter sprotno odpravljanje napak na spojih in konektorjih.

• Language: Slovenian
• Keywords: optično dostopovno omrežje, DVBC-P2P, DVBC-P2MP, postopek izgradnje, kvaliteta prenosa signala.
• Work type: Bachelor thesis/paper
• Organization: FE - Faculty of Electrical Engineering
• Year: 2016
• PID: 20.500.12556/RUL-85897
• Publication date in RUL: 28.09.2016

Secondary language

• Language: English
• Title: Optical Access Network Based on DVB-C Technology

Abstract

Radio frequency digital and analogue signals, that until recently were transmitted through copper cables (coaxial cables), today are increasingly being replaced with optical fibre cables transmission. Advantages of the optical access network are primarily reflected in the bandwidth, quality and data transfer rate. The bandwidth provides low attenuation with optical fibre cable, an appropriate light source and optical detector. Quality of the optical fibre cable transmission is substantially higher because the optical fibre cable is dielectric cable, i.e. electromagnetic interference (lightning, crosstalk between individual glass wires) does not affect the signal. Capacity of the optical fibre amounts to approximately 10 THz bandwidth that is available to the optical fibre and that can be used for communication purposes. From this aspect, the optical fibre is the best bandwidth medium. The subject thesis deals with the optical access network with DVB-C technology, focusing on two architectures. The first one is DVBC-P2P, that provides a direct optical connection between the user's modem and the central station. The second architecture is DVBC-GPON where a single optical fibre, using fibre optic splitters, is connected with multiple customers. In the practical part of the thesis, we have presented in more detail the design of the optical network, i.e. the connection of optical fibres with fixed welded connection or connectors, preparation of optical couplers for protection of welds, attenuation measurement, preparation of signals from different sources, conversion of RF signals to optical network signals and vice versa as well as intensifying of optical signals. We will present the essential characteristics of quality transmission of DVB-C signal to the end user with two different architectures, which is also the main objective of our thesis. The challenges we were facing during the performance of the practical part of the thesis were related primarily to the network building design, provision of welding and measuring equipment and real-time fixing of defects on connections and connectors.

• Keywords: optical access network, DVBC-P2P, DVBC-P2MP, building design, signal transmission quality.