Thesis (MScIng)--University of Stellenbosch, 2008. / ENGLISH ABSTRACT: The Applications of Superconductors in Cellular Network Base
Stations
R. Du Toit
Department of Electronic Engineering
University of Stellenbosch
Private Bag X1, 7602 Matieland, South Africa
Thesis: MScEng (E&E)
March 2008
Wireless communications have increasingly become part of our world. The growth of radio
frequency (RF) wireless communications has led to an increasing demand for frequency
spectrum licenses, increased system capacity and larger user bandwidths. These demands
lead to frequent improvements on the physical and higher layers of wireless communication
protocols. Changes in the physical layer are frequently followed by the need for replacement
of dedicated hardware components. The need therefore exists for a more general
and programmable physical layer. A more general and programmable radio architecture
implies increased radio front-end performance without losing programmability.
The contribution of this thesis is the analysis of how superconductor electronics (SCE)
using Rapid Single Flux Quantum (RSFQ) logic may advance wireless radio front-ends
by providing a general-purpose programmable radio architecture. Superconductor analogue
to digital converters (ADCs) are employed as high performance, programmable
digitization structures. Once a received signal is digitized, SCE can be used to rapidly
do recursive operations such as synchronization and multi-path delay estimation. These
operations are based on correlation, and for evaluation of such operations with SCE the
popular CDMA multiplexing method is studied along with the WCDMA protocol used
in the 3G UMTS standard.
Two delta-type oversampling superconductor ADC modulator designs are presented
and evaluated along with a hybrid decimation filter design, using both the benefits of SCE and room temperature electronics. A fast RSFQ correlator design is also presented
and evaluated for use in a multi-path estimation structure. A rapid multi-path delay
estimation architecture based on fast RSFQ circular data buffers and correlators is presented.
The architecture uses the fast speeds of RSFQ logic to obtain accurate path delay
estimates in a rapidly changing wireless environment.
It is concluded that RSFQ-based wireless receiver components offer promising new
options for data conversion, correlation and multi-path delay estimation implementations. / AFRIKAANSE OPSOMMING: The Applications of Superconductors in Cellular Network Base
Stations
R. Du Toit
Department of Electronic Engineering
University of Stellenbosch
Private Bag X1, 7602 Matieland, South Africa
Thesis: MScEng (E&E)
March 2008
Draadlose kommunikasie word al hoe meer deel van ons wêreld. Groei in radiofrekwensietipe
kommunikasie het gelei tot ’n toenemende aanvraag na frekwensiespektrum lisensies,
vergrote stelselkapasiteit en groter gebruikerbandwydtes. Hierdie aanvrae lei tot gereelde
en spoedige verbeteringe op die fisiese en hoër lae van huidige draadlose kommunikasieprotokol.
Veranderinge in die fisiese laag vereis gewoonlik dat toegewyde hardewarde komponente
vervang word. Die behoefte bestaan dus vir ’n meer algemene, programmeerbare
fisiese laag. Dit vereis dus ’n verbetering in die radio-ontvanger se komponente naaste
aan die antenna sonder om programmeerbaarheid te verloor.
Die bydrae van hierdie tesis is hoofsaaklik die analise van hoe supergeleierelektronika
wat van Rapid Single Flux Quantum (RSFQ) logika gebruik maak, huidige draadlose
sellulêre basisstasies se fisiese laag kan verbeter deur ’n meer algemene en programmeerbare
radio-argitektuur op te lewer. Supergeleier analoog-na-syfer omsetters (ADCs) word
bestudeer as moontlike programmeerbare versyferingstrukture wat steeds hoë werkverrigting
lewer. Wanneer ’n ontvangde sein in digitale vorm omgesit is, kan supergeleierelektronika
gebruik word om vinnig rekursiewe operasies uit te voer. Voorbeelde van sulke
operasies is sinkronisasie en die waardebepaling van die vertraging van verskillende paaie
wat ’n sein volg na die ontvanger. Hierdie spesifieke operasies se werking is gebaseer op korrelasie,
en vir die evaluasie van sulke operasies met supergeleierelektronika is die gewilde wyeband-CDMA (WCDMA) protokol wat gebruik word in die 3G UMTS-standaard.
Twee supergeleier-delta-tipe oorversyferings-ADC-moduleerderontwerpe word voorgelê
en evaluasie word daarop gedoen saam met ’n hibriede desimasiefilterontwerp wat gebruik
maak van beide die voordele van supergeleierelektronika en kamertemperatuurelektronika.
’n Vinnige RSFQ-korreleerder word ook voorgelê en evaluasie word daarop gedoen
vir gebruik binne ’n multi-padvertraging-waardebepalerstruktuur. Hierdie struktuur wat
gebaseer is op RSFQ sirkulêre buffers en korreleerders, word voorgelê. Die waardebepaler
maak gebruik van die spoed van RSFQ-logika om akkurate multi-padvertragingswaardes
te bepaal in ’n vinnig veranderende draadlose omgewing.
Die gevolgtrekking word gemaak dat RSFQ-gebaseerde draadlose ontvangerkomponente
groot voordele in versyfering-, korreleerder- en multi-padvertragingsbepaler-toepassings
bied.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:sun/oai:scholar.sun.ac.za:10019.1/20433 |
| Date | 03 1900 |
| Creators | Du Toit, Riaan |
| Contributors | Fourie, C. J., Stellenbosch University. Faculty of Engineering. Dept. of Electrical and Electronic Engineering. |
| Publisher | Stellenbosch : Stellenbosch University |
| Source Sets | South African National ETD Portal |
| Language | en_ZA |
| Detected Language | Unknown |
| Type | Thesis |
| Format | xxii, 131 leaves : ill. |
| Rights | Stellenbosch University |
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