Modulation options for OFDM-based waveforms: classification, comparison, and future directions
Tarih
2019Yazar
Jaradat, Ahmad M.
Hamamreh, Jehad M.
Arslan, Hüseyin
Üst veri
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This paper provides a comparative study on the performance of different modulation options
for orthogonal frequency division multiplexing (OFDM) in terms of their spectral efficiency, reliability,
peak-to-average power ratio, power efficiency, out-of-band emission, and computational complexity. The
modulation candidates are classified into two main categories based on the signal plane dimension they
exploit. These categories are: 1) 2-D signal plane category including conventional OFDM with classical
fixed or adaptive QAM modulation and OFDM with differential modulation, where information is conveyed
in changes between two successive symbols in the same subcarrier or between two consecutive subcarriers in
the same OFDM symbol and 2) 3-D signal plane category encompassing: a) index-based OFDM modulation
schemes which include: i) spatial modulation OFDM, where information is sent by the indices of antennas
along with conventional modulated symbols and ii) OFDM with index modulation, where the subcarriers’
indices are used to send additional information; b) number-based OFDM modulation schemes which
include OFDM with subcarrier number modulation, in which number of subcarriers is exploited to convey
additional information; and c) shape-based OFDM modulation schemes which include OFDM with pulse
superposition modulation, where the shape of pulses is introduced as a third new dimension to convey
additional information. Based on the provided comparative study, the relationship and interaction between
these different modulation options and the requirements of future 5G networks are discussed and explained.
This paper is then concluded with some recommendations and future research directions.