Kvaliteta prijenosa u mobilnim radiokomunikacijskim sustavima s diskretnom modulacijom faze

scientific master's theses

• Author: Marin Kolega
• Mentor: Branka Zovko-Cihlar (mentor)
• Committee member: Borivoj Modlic (predsjednik povjerenstva)
• Committee member: Branka Zovko-Cihlar (član povjerenstva)
• Committee member: Slavko Šarić (član povjerenstva)
• Granter: University of Zagreb; Faculty of Electrical Engineering and Computing; Zagreb
• Defense date and country: 1999-07-07, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Electrical Engineering; Radio Communications
• Universal decimal classification (UDC): 621.3 - Electrical engineering

Abstract

Da bi se ocijenile karakteristike određenog modulacijskog postupka prije same konstrukcije uređaja, potrebno je razviti odgovarajuće modele kanala da bi se adekvatno opisala okolina rasprostiranja. Takve analize značajno smanjuju cijenu razvoja kompleksnih sustava smanjujući potrebu za skupim uređajima pri određivanju karakteristika. Teoretski modeli još imaju tu prednost da može raditi usporedba kanala pri raznim komunikacijskim strategijama, da bi se dobila mjera kvalitete.
U ovom radu, određene su širokopojasne karakteristike simuliranog modela, i iskorištene da bi se dobili detaljniji pokazatelji kanala, te su prezentirane grafički.
Prostor unutar građevina okarakteriziran je mnoštvom puteva radio valova od odašiljača k prijemniku i stoga je definiran kao okolina s višestrukim putevima.
Ovaj rad pokazuje da fizikalni opis impulsnog odziva kanala nije samo dobra podloga za razvoj radiokomunikacijskih sustava u smislu najboljeg iskorištenja radijskog spektra, nego je i dobro istraživanje prirode i mehanizma rasprostiranja za kanale unutar građevina. Model zasnovan na prijašnjim mjerenjima je korišten pri usporedbi BER za modulacijske postupke BPSK, FSK and π/4 DQPSK.
Iako modulacijski postupak BPSK ima najniži BER u usporedbi s FSK i π/4 DQPSK, ipak je π/4 DQPSK ocijenjen kao najbolji za komunikaciju unutar građevina zbog svoje visoke spektralne efikasnosti.

Abstract (english)

ln order to evaluate the characteristics for given channel modulation technique before construction, some model of the channel must be developed that adequately describes the environment. Such analysis reduces the cost of developing a complex system by reducing the amount of hardware that has to be developed for evaluation of performance. Theoretical models have a second advantage in their ability to reproduce a channel for comparison between various communication strategies, resulting in an accurate measure of relative performance.
In this thesis, wideband characteristics are determined from the simulation model, and found to give access to more detailed information on the channel than is obtainable through physical measurement. The results of the wideband simulations are graphically presented.
The indoor environment is characterised by a large number of propagation paths from the transmitterto receiver, and is hence classed as a multipath environment.
This thesis has shown that a physically based description of the channel impulse response is required not only for evaluation and development of in-door communication systems that attempt to use the limited available radio bandwidth to best effect, but also for investigation of the propagation mechanisms involved in indoor communications. A model based on previous measurements has been presented and applied to BER estimation for BPSK, FSK and π/4 DQPSK.
Even though BPSK has the lowest BER in comparison to π/4 DQPSK and FSK, π/4 DQPSK is evaluated as best modulation technique due to its spectral efficiency.

• Keywords: Mobilni komunikacijski sustav; modulacijski postupak; radiokomunikacijski kanali
• Keywords (english): Modulation technique; indoor communication systems
• Language: croatian
• URN:NBN: urn:nbn:hr:168:918829
• Study programme: Title: Postgraduate master programme in electrical engineering; Study programme type: university; Study level: postgraduate; Academic / professional title: Magistar znanosti elektrotehnike (Magistar znanosti elektrotehnike)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Closed access
• Created on: 2019-03-29 14:48:33