Two-radii 8APSK and Two-radii 16APSK Modulations as Alternatives to 8PSK and 16QAM

Dayan Guimarães

doi:10.14209/jcis.2018.30

Abstract

In regard to the M-ary phase-shift keying (MPSK) modulation and the quadrature amplitude modulation (MQAM), MPSK is preferred up to M = 8, with MQAM being the most common choice for M > 8. In this letter, the modulations two-radii 8-ary and 16-ary amplitude-phase shift keying (APSK), respectively named 2r8APSK and 2r16APSK, are proposed as alternatives to 8PSK and square 16QAM, in this order. The 2r8APSK achieves higher power efficiency than the 8PSK, at the cost of a higher peak-to-average power ratio (PAPR) and a slightly more complex receiver. The 2r16APSK yields lower PAPR than the 16QAM, with roughly the same receiver complexity, but at the cost of a slightly lower power efficiency. Comparisons with other APSK-based modulations are made as well.

Highlights

T HE M-ary phase-shift keying (MPSK) modulation and the M-ary quadrature amplitude modulation (MQAM) are widely used in digital communication systems. Both have the same spectral efficiency, but the MPSK has the advantage of lower receiver complexity, since there is no need for estimating any threshold or received signal levels, thanks to the equal-energy symbols
For M > 8 it is worth paying for a higher receiver complexity of the MQAM with respect to the MPSK, since large performance gains are attained by the former
The real and imaginary parts of the complex envelope of the modulated signals went through low-pass root raised cosine (RRC) pulse shaping filters whose roll-off factors were varied from 0.1 to 1 in steps of 0.05

Summary

INTRODUCTION

T HE M-ary phase-shift keying (MPSK) modulation and the M-ary quadrature amplitude modulation (MQAM) are widely used in digital communication systems. Both have the same spectral efficiency, but the MPSK has the advantage of lower receiver complexity, since there is no need for estimating any threshold or received signal levels, thanks to the equal-energy symbols. Signals having non-constant envelope are special candidates to exhibit high PAPR, making it difficult the project of large dynamic range and power-efficient amplifiers.

PROPOSED MODULATIONS

PAPR ANALYSIS

BER ANALYSIS

CFM ANALYSIS

CONCLUSIONS