The aim of this dissertation was to investigate peak-to-average power ratio (PAPR) reduction techniques
for filter bank multicarrier (FBMC) modulated systems. Research into current PAPR reduction
techniques in FBMC and orthogonal frequency division multiplexing (OFDM) found that the active
constellation extension (ACE) method has not been exploited for use in FBMC systems. This is, in
part, due to the complexities involved in signal processing inherent of FBMC systems, as well as
FBMC being a relatively new subject matter in the telecommunications field.
The outcomes of the dissertation were four novel PAPR reduction techniques for FBMC systems.
These techniques can be split up into two namely linear programming optimization ACE-based techniques
and overlapping ACE techniques. The techniques compensate for the overlapping symbols in
FBMC by utilizing a frame based approach. This characteristic makes them ideal candidates to be
applied in burst transmission. Furthermore, because an ACE based technique is used, they do not
require the transmission of side information. The PAPR performance of the techniques are shown to
match, or in some cases improve, current PAPR techniques for FBMC. The analysis of the proposed
approaches also address some complexity issues with current FBMC implementations.
The out-of-band (OOB) interference of the techniques under clipping scenarios is investigated. It is
shown that the OOB interference can be minimized whilst still maintaining good PAPR performance.
Additional results are also provided by means of a study of the PAPR reduction techniques proposed
as applied to a high power amplifier based model. The corresponding power amplifier efficiency as
well as bit-error rate (BER) degradation are investigated and compared to other standard techniques
for PAPR reduction in FBMC systems. It was found that the proposed techniques can achieve a
higher amplifier efficiency than existing techniques at a marginal trade-off in BER degradation. This
BER degradation is lower than existing techniques due to the marginal increase in average transmit
power.
As illustrated by exhaustive simulations, the single scaling and overlapping smart gradient-project
ACE-based techniques proposed, are ideal candidates for practical implementation in systems employing
the low complexity polyphase implementation of FBMC modulators. The methods are shown
to offer significant PAPR reduction and increase the feasibility of FBMC as a replacement modulation
system for OFDM.
Die doel van hierdie verhandeling is om top-tot-gemiddelde drywingsverhouding (PAPR) verminderingstegnieke
vir filterbank veelvuldige draer (FBMC) -gemoduleerde stelsels te ondersoek. Huidige
PAPR verminderingstegnieke in FBMC en ortogonale frekwensie verdeling multipleksering
(OFDM) is ondersoek en daar is bevind dat die aktiewe konstellasie uitbreidingsmetode (ACE) nog
nie vantevore ontgin is in FBMC stelsels nie. Dit is gedeeltelik as gevolg van die inherente kompleksiteit
van seinverwerking in FBMC stelsels en ook omdat FBMC n relatief nuwe onderwerp in die
veld van telekommunikasie is.
Die resultate van hierdie verhandeling is vier unieke PAPR verminderingstegnieke vir FBMC
stelsels. Hierdie tegnieke kan opgedeel word in lineêre programeringsgeoptimiseerde tegnieke en
oorvleuelende ACE tegnieke. Om vir die oorvleueling van simbole in FBMC te vergoed, word n
raamgebaseerde benadering gebruik. Hierdie kenmerk maak hierdie tegnieke ideaal vir vlaaguitsending.
Omdat n ACE-gebaseerde tegniek gebruik word, is transmissie van kant inligting onnodig. Die
PAPR werkverrigting van dié tegnieke is op standaard met, en in sommige gevalle n verbetering op
huidige PAPR tegnieke vir FBMC. Die ontleding van die voorgestelde benaderings spreek ook die
kompleksiteitkwessies met die implementering van huidige tegnieke aan.
Die buite band (OOB) steuring van die tegnieke onder geknipte scenarios word ondersoek. Daar word
getoon dat die OOB steuring verminder kan word terwyl goeie PAPR verrigting gehandhaaf word.
Addisionele studieresultate word ook voorsien deur n studie van die voorgestelde PAPR reduksietegnieke
toegepas op n hoë drywing versterker (HPA)model. Die ooreenstemmende drywingsversterker
doeltreffendheid asook die degradering van die bit fout waarde (BER) is ondersoek en vergelyk met
ander tegnieke vir PAPR vermindering in FBMC stelsels. Daar is bevind dat die voorgestelde tegnieke
n hoër drywing versterker doeltreffendheid kan bereik as bestaande tegnieke afgespeel ten koste van
n marginale BER degradasie. Hierdie degradasie is laer as bestaande tegnieke as gevolg van die
marginale toename in gemiddelde uitsendingskrag.
Uitvoerige simulasies toon dat die voorgestelde enkel skalering en oorvleuelende slim gradiënt projek
ACE gebaseerde tegnieke die ideale kandidate is vir praktiese toepassing in stelsels wat gebruik
maak van die lae kompleksiteit veelfase toepassing van FBMC modulators. Dié metodes bring n
beduidende PAPR vermindering te weeg en maak FBMC meer haalbaar as n vervanging modulasie
stelsel vir OFDM.
