Title Određivanje optimalnih kapaciteta mobilnih satelitskih veza u pomorstvu
Title (english) Optimal Capacity Sizing of Satellite Links in Mobile Maritime Networks
Author Srećko Krile
Mentor Mladen Kos (mentor)
Committee member Vjekoslav Sinković (član povjerenstva)
Committee member Mladen Kos (član povjerenstva)
Committee member Luka Neralić (član povjerenstva)
Committee member Damir Kalpić (član povjerenstva)
Committee member Marijan Kunštić (član povjerenstva)
Granter University of Zagreb Faculty of Electrical Engineering and Computing (Department of Telecommunications) Zagreb
Defense date and country 2000-12-15, Croatia
Scientific / art field, discipline and subdiscipline TECHNICAL SCIENCES Electrical Engineering Telecommunications and Informatics
Universal decimal classification (UDC ) 621.3 - Electrical engineering
Abstract Razvijen je model za određivanje optimalnih kapaciteta za više satelitskih linkova u mobilnim mrežama, a u smislu planiranja proširenja za vrijeme eksploatacije. To je nužno zbog ubrzanog porasta prometnih zahtjeva od strane mobilnih korisnika, a uvođenje nove opreme može uzrokovati vrlo velike troškove. U postupku planiranja operator LESO (Land Earth Station Operator) mora odrediti optimalnu strategiju povećanja ili prenamjene kanalske opreme, s ciljem minimizacije ukupnih troškova proširenja. U traganju za optimalnom sekvencijom proširenja, prenamjene kapaciteta mogu biti ponekad pogodnije od uvođenja nove opreme. Model dopušta prenamjene kanalske opreme s jednoga na drugi satelitski link, i to u oba smjera, iako ograničenja mogu biti uvedena. Mobilna satelitska mreža Inmarsat (International Mobile Satellite Organization) nastala je, prije svega, zbog potreba pomorstva. Danas je još uvijek najvažniji sustav u pomorskim komunikacijama, ali pruža jednako kvalitetne usluge i ostalim vrstama mobilnih korisnika. Satelitske se veze ostvaruju preko četiri geostacionarna satelita. “Veliki” operatori (LESO) obično imaju pristup na više satelita, uglavnom na dva ili tri, a to ostvaruju preko satelitskih linkova kroz partnerske zemaljske postaje (LES). U literaturi su slični problemi poznati kao CEP (Capacity Expansion Problem). U tom modelu nedostatni kapaciteti su dopušteni, što označavamo s CEPS (Capacity Expansion Problem with Shortages). Razvijajući optimizacijski model preko mreže tokova, a koristeći postupak mrežnog planiranja, precizno su određene karakteristike ekstremnosti tokova i ispitane sve mogućnosti proširenja. Na osnovi toga razvijen je djelotvoran algoritam na načelu dinamičkog programiranja, koji optimizira proširenja kapaciteta na tri satelitska linka. Najveća količina računanja se troši na određivanju minimalne cijene između dvije određene kapacitivne točke. Heuristički algoritam je uspješno testiran na mnogim primjerima. Dokazana je njegova djelotvornost i visoka efikasnost u usporedbi s drugim sličnim algoritmima koji se koriste egzaktnim ili heurističkim pristupom. Heuristika postiže optimalni rezultat s prihvatljivom količinom računanja. Cilj je bio razviti efikasno sredstvo koje pomaže menadžmentu LESO-a u određivanju iznosa i vremena povećanja ili prenamjene kapaciteta u planskom razdoblju s ograničenim brojem perioda. Pokazalo se da je ovaj optimizacijski alat primjenljiv za kratkoročno i srednjeročno planiranje proširenja kapaciteta u mobilnim satelitskim mrežama.
Abstract (english) A deterministic expansion model for sizing of N satellite links in mobile networks during exploitation is being developed. Expansions are necessary because of enormous increase of traffic demands, but new constructions could be very expensive. In the planning process it can help Land Earth Station Operator (LESO) to find the optimal capacity-expansion policy for new constructions and conversions of channel equipment that minimizes the total cost. In certain situation conversion could be much more appropriate than expansion. The model allows conversions from one satellite link to another in both directions, but limitations can be imposed. Inmarsat was initially established as International Maritime Satellite Organization, developed for maritime communication purpose. Today, it is still the most important mobile satellite network in the maritime world, although it provides quality services to other types of mobile users. Communication links are made through four geostationary satellites. Big LESOs usually have access to more then one satellite, usually two or three, using satellite link capacities through partnership LESs (Land Earth Station). In literature that problem is well known as CEP (Capacity Expansion Problem). In this model capacity shortages are allowed so we denote it as CEPS (Capacity Expansion Problem with Shortages). Using network flow approach and network planning method, properties of extreme point solution and acceptable policies are identified. We developed a dynamic programming algorithm that can be used to find an optimal solution for expansion of three different satellite links (capacity types), in which converted capacities can be rearranged. The most of computational effort is spent on minimizing expansion cost between two capacity points. Heuristic algorithm is tested on many examples, and its efficiency is compared with algorithm based on exact and heuristic approach. The heuristic algorithm is very effective, providing an optimal result with reasonable effort. The objective was to develop an effective planning tool to help LESO-managers in sizing and timing of capacity expansions and conversions in multi-period planning horizon. We observe that it is suitable in short-term and medium-term planning and may be used in the optimal capacity sizing of satellite links in mobile networks.
Keywords
Mobilne telekomunikacije
satelitske mreže
prijenosne veze
planiranje kapaciteta
problem optimalnog proširenja kapaciteta
Keywords (english)
Mobile telecommunications
satellite networks
transmission link
capacity planning
capacity expansion problem
Language croatian
URN:NBN urn:nbn:hr:168:929192
Study programme Title: Postgraduate doctoral university study Study programme type: university Study level: postgraduate Academic / professional title: doktor/doktorica znanosti (doktor/doktorica znanosti)
Type of resource Text
File origin Born digital
Access conditions Closed access
Terms of use
Created on 2019-04-11 12:43:00