Title
Improving the performance of LoRa based wireless transceivers
Creator
Jovalekić, Nikola, 1982- 14571623
Copyright date
2018
Object Links
Select license
Autorstvo-Nekomercijalno 3.0 Srbija (CC BY-NC 3.0)
License description
Dozvoljavate umnožavanje, distribuciju i javno saopštavanje dela, i prerade, ako se navede ime autora na način odredjen od strane autora ili davaoca licence. Ova licenca ne dozvoljava komercijalnu upotrebu dela. Osnovni opis Licence: http://creativecommons.org/licenses/by-nc/3.0/rs/deed.sr_LATN Sadržaj ugovora u celini: http://creativecommons.org/licenses/by-nc/3.0/rs/legalcode.sr-Latn
Language
English
Cobiss-ID
Theses Type
Doktorska disertacija
description
Datum odbrane: 18. 12. 2018.
Other responsibilities
mentor
Drndarević, Vujo, 1953- 12394855
član komisije
Nešković, Aleksandar, 1968- 6977639
član komisije
Jevtić, Nenad, 1975- 12891495
član komisije
Popović, Ivan T., 1971-12827495
član komisije
Olćan, Dragan, 1977-
Academic Expertise
Tehničko-tehnološke nauke
University
Univerzitet u Beogradu
Faculty
Elektrotehnički fakultet
Alternative title
Poboljšanje performansi bežičnih primopredajnika zasnovanih na LoRa modulaciji
Publisher
[N. Jovalekić]
Format
XIV, 146 listova
description
Technical Sciences, Electrical Engineering - Electronics / tehničke nauke, elektrotehnika
- elektronika
Abstract (en)
The use of wireless technologies dominates the everyday life of a modern
society. Internet of Things, the new paradigm of interaction between humans and
their environment, unlocks advanced scenarios of collecting information from the
real world using various sensors. One of the recently developed technologies, that is
a potential candidate to become a prevalent technology exploited in the Internet of
Things arena, is LoRa. The technology has been extensively explored in numerous
theoretical and experimental studies, and a signicant insight has been gained.
However, to provide a deeper insight into LoRa technology capabilities, the novel
LoRa transceiver with improved characteristics in terms of sensitivity and immunity
to external interferences has been developed. This work presents the development
methodology, as well as the laboratory experiments that veried the transceiver's
superior characteristics. In addition, it provides performance comparison with two
widely adopted commercial solutions. The results have shown that the novel LoRa
transceiver has an improved sensitivity of 15{25 dB, while the eld experiments
revealed higher immunity to external interferences.
The second part of the thesis explores LoRa capabilities and limitations by deploying
the novel transceiver along with the two commercial transceivers in various
experimental scenarios. Namely, the transceivers were deployed in very long and
ultra-long distance links providing two propagation conditions: line-of-sight over
land and line-of-sight over seawater. In addition, obstructed line-of-sight scenario
over sea water has been investigated. The results indicate that 112km long links
over land are fully feasible using low-cost, rubber-duck, omnidirectional antennas
and standard output powers in two ISM frequency bands, 868MHz and 434 MHz,
provided that line-of-sight is guaranteed. Furthermore, it has been shown that such
links can be established for virtually any combination of LoRa parameters, since
the experiments were carried out deploying three dierent, characteristic, set of
LoRa parameters, namely: for spreading factors of SF 2 f7; 10; 12g, within a xed
bandwidth of BW = 125 kHz, and deploying xed coding rate of CR = 4=6. The
short and long-term temporal analysis of the links revealed that the main cause
of packet reception rate deterioration are multipath propagation eects, while the
i
radio-interference has negligible eects on packet reception rate. Furthermore, it
has been demonstrated that ultra-long distance links of 316 km are also possible, in
both ISM bands of interest, but using only novel LoRa transceiver. The signicance
of the results is amplied by the fact that omnidirectional antennas were used in
the experiments with standard output powers.
Finally, the experiments over seawater revealed that links up to 22 km in line-ofsight
mode are fully feasible using low-cost, rubber-duck, omnidirectional antennas
and standard output powers with link margin yielding more than 15 dB in both ISM
frequency bands. Moreover, the links in obstructed line-of-sight mode over 28 km are
also possible in ISM 434MHz band; however, there are certain limitations when it
comes to their practical implementations since costly and bulky antennas are needed
on both sides and transmission reliability is not guaranteed.
Abstract (sr)
Savremene bežične tehnologije značajno utiču na svakodnevni život modernog
društva. Internet stvari, nova paradigma interakcije čoveka sa njegovom
okolinom, omogućava brzo prikupljanje i selektovanje informacija iz realnog sveta
koristeći različite vrste senzora. Jedna od novih tehnologija, koja je potencijalni
kandidat da postane najmasovnije upotrebljavana tehnologija u takvim sistemima
jeste upravo LoRa. Ova tehnologija je, do sada, ispitivana kroz brojne teoretske i
eskperimentalne studije.
Da bi se obezbedio dublji uvid u mogućnosti tehnologije, razvijen je novi LoRa
primopredajnik sa poboljšanim karakteristikama u smislu osetljivosti i imunosti na
smetnje. U tezi je prikazana metodologija razvoja novog primopredajnika i dati su
rezultati laboratorijskih ispitivanja koji verikuju poboljšane performanse. Takodje
su uradjena uporedna ispitivanja novorazvijenog primopredajnika sa dva veoma
rasprostranjena komercijalna primopredajnika. Rezultati ispitivanja su pokazali,
da novi LoRa primopredajnik ima poboljsanu osetljivost u opsegu 15 {25 dB, dok su
rezultati ispitivanja u realnim uslovima dodatno utvrdili i veću imunost na spoljnje
smetnje.
U drugom delu teze su dati rezultati eksperimenta izvršenih u realnim uslovima.
Novi LoRa primopredjanik je ispitivan na vrlo dugačkim i izuzetno dugačkim trasama
u dva karakteristična propagaciona scenarija: kada je zadovoljen uslov optičke vidljivosti i kada je optička vidljivost blokirana izmedju prijemnika i predajnika. U ovim eksperimentima linkovi su formirani iznad kopna i iznad mora.
Rezultati eksperimenata su pokazali da, ukoliko je obezbedjena optička vidljivost
izmedju prijemnika i predajnika, linkovi u dužini od 112 km iznad kopna u potpunosti
su izvodljivi, koristeći omnidirekcione antene i standardnu izlaznu snagu u
oba ISM opsega, 868MHz i 434 MHz. Takodje, pokazano je da takvi linkovi mogu
biti uspostavljeni za bilo koju kombinaciju LoRa parametara, ukljućujući i komercijalne
primopredajnike, s obzirom na to da su eksperimenti izvršeni za tri karakteristična seta LoRa parametara, naime: koristeći faktore širenja SF 2 f7; 10; 12g
unutar ksnog LoRa opsega od BW = 125 kHz i upotrebom zaštitnog kodovanja
iii CR = 4=6. Analiza parametara linka u vremenskom domenu je pokazala da je
glavni uzrok gubitka paketa mulitpath propagacija signala, dok je radio-interferencija
imala zanemariv doprinos gubitku paketa. Dalje je pokazano da su izuzetno dugački
linkovi, dužine 316 km, izvodljivi koristeći novorazvijeni primopredajnik u oba ISM
opsega od interesa, upotrebljavajuci omnidirekcione antene i standardne izlazne
snage. Konačno, eksperimenti iznad morske površine su pokazali da, ukoliko postoji
optička vidljivost izmedju prijemnika i predajnika, linkovi u dužini od 22 km su
mogući i to u oba ISM opsega od interesa, koristeći omnidirekcione antene i standardne
izlazne snage; margina linka od 15 dB u oba frekvencijska opsega implicira da
su moguća i veća rastojanja. Eksperimentalno je utvrdjeno i da, ukoliko je optička
vidljivost preko morske površine izmedju prijemnika i predajnika blokirana, moguće
je uspostaviti link u dužini od 28 km na frekvenciji od 434 MHz, upotrebom antena
sa većim pojačanjem, ali kvalitet prenosa u ovom slučaju ne može biti garantovan.
Authors Key words
IoT, LPWAN, LoRaWAN, LoRa, transceiver, long range, sensitivity,
interference, immunity
Authors Key words
IoT, LPWAN, LoRaWAN, LoRa, primopredajnik, dugački linkovi,
osetljivost, interferencija, imunost
Classification
621.396.61:004(043.3)
Type
Tekst
Abstract (en)
The use of wireless technologies dominates the everyday life of a modern
society. Internet of Things, the new paradigm of interaction between humans and
their environment, unlocks advanced scenarios of collecting information from the
real world using various sensors. One of the recently developed technologies, that is
a potential candidate to become a prevalent technology exploited in the Internet of
Things arena, is LoRa. The technology has been extensively explored in numerous
theoretical and experimental studies, and a signicant insight has been gained.
However, to provide a deeper insight into LoRa technology capabilities, the novel
LoRa transceiver with improved characteristics in terms of sensitivity and immunity
to external interferences has been developed. This work presents the development
methodology, as well as the laboratory experiments that veried the transceiver's
superior characteristics. In addition, it provides performance comparison with two
widely adopted commercial solutions. The results have shown that the novel LoRa
transceiver has an improved sensitivity of 15{25 dB, while the eld experiments
revealed higher immunity to external interferences.
The second part of the thesis explores LoRa capabilities and limitations by deploying
the novel transceiver along with the two commercial transceivers in various
experimental scenarios. Namely, the transceivers were deployed in very long and
ultra-long distance links providing two propagation conditions: line-of-sight over
land and line-of-sight over seawater. In addition, obstructed line-of-sight scenario
over sea water has been investigated. The results indicate that 112km long links
over land are fully feasible using low-cost, rubber-duck, omnidirectional antennas
and standard output powers in two ISM frequency bands, 868MHz and 434 MHz,
provided that line-of-sight is guaranteed. Furthermore, it has been shown that such
links can be established for virtually any combination of LoRa parameters, since
the experiments were carried out deploying three dierent, characteristic, set of
LoRa parameters, namely: for spreading factors of SF 2 f7; 10; 12g, within a xed
bandwidth of BW = 125 kHz, and deploying xed coding rate of CR = 4=6. The
short and long-term temporal analysis of the links revealed that the main cause
of packet reception rate deterioration are multipath propagation eects, while the
i
radio-interference has negligible eects on packet reception rate. Furthermore, it
has been demonstrated that ultra-long distance links of 316 km are also possible, in
both ISM bands of interest, but using only novel LoRa transceiver. The signicance
of the results is amplied by the fact that omnidirectional antennas were used in
the experiments with standard output powers.
Finally, the experiments over seawater revealed that links up to 22 km in line-ofsight
mode are fully feasible using low-cost, rubber-duck, omnidirectional antennas
and standard output powers with link margin yielding more than 15 dB in both ISM
frequency bands. Moreover, the links in obstructed line-of-sight mode over 28 km are
also possible in ISM 434MHz band; however, there are certain limitations when it
comes to their practical implementations since costly and bulky antennas are needed
on both sides and transmission reliability is not guaranteed.
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