Abstract:
This paper presents four novel techniques for peak-to-average power ratio (PAPR) reduction in filter bank multicarrier
(FBMC) modulation systems. The approach extends on current PAPR reduction active constellation extension (ACE)
methods, as used in orthogonal frequency division multiplexing (OFDM), to an FBMC implementation as the main
contribution.
The four techniques introduced can be split up into two: linear programming optimization ACE-based techniques
and smart gradient-project (SGP) ACE techniques. The linear programming (LP)-based techniques compensate for
the symbol overlaps by utilizing a frame-based approach and provide a theoretical upper bound on achievable
performance for the overlapping ACE techniques. The overlapping ACE techniques on the other hand can handle
symbol by symbol processing. Furthermore, as a result of FBMC properties, the proposed techniques do not require
side information transmission. The PAPR performance of the techniques is shown to match, or in some cases improve,
on current PAPR techniques for FBMC. Initial analysis of the computational complexity of the SGP techniques indicates
that the complexity issues with PAPR reduction in FBMC implementations can be addressed.
The out-of-band interference introduced by the techniques is investigated. As a result, it is shown that the
interference can be compensated for, whilst still maintaining decent PAPR performance. Additional results are also
provided by means of a study of the PAPR reduction of the proposed techniques at a fixed clipping probability. The bit
error rate (BER) degradation is investigated to ensure that the trade-off in terms of BER degradation is not too severe.
As illustrated by exhaustive simulations, the SGP ACE-based technique 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.
