研究目的

Investigating the construction of a coded modulation scheme based on regular amplitude and phase shift keying (RAPSK) modulations to address the limitations of QAM constellations in the presence of phase noise and high peak to average power ratio (PAPR).

研究成果

The paper concludes that the proposed RAPSK constellations are flexible in their design and have several desirable characteristics from an engineering point of view, most notably with respect to PAPR, robustness to phase noise, and pre-equalization. Moreover, they can be constructed in a fully scalable way up to an arbitrarily high number of points, and set-partitionings of the points are naturally yielded by the structure itself. This allows to obtain constellations whose number of points is any power of 2 without substantial changes in the set-partitioning, coding and decoding procedure, contrary to QAM constellations for which the number of points is typically chosen as an even power of 2 to simplify detection and equalization procedures.

研究不足

The study acknowledges that the approximations used for LLR computation hold overall when the SNR is high enough to enable a small inter-ring distance D, and the innermost ring radius r0 is large with respect to the inter ring distance. For applications where high-density constellations are preferred, the SNR is expected to be large, and targeting lower PAPR values will ensure that both conditions are met.