Energy-Efficient Modulation Analysis: HQAM over Nakagami-m Fading Channels

Abstract

Future communication technologies are anticipated to facilitate applications necessitating extremely high data speeds while maintaining energy efficiency. In this regard, hexagonal quadrature amplitude modulation (HQAM) is an attractive technique to achieve high-rate transmission without increasing the bandwidth, due to its dense arrangement of symbols on the two-dimensional plane. Nonetheless, due to its hexagonal lattice structure, accurately assessing the error probability is challenging, if not unfeasible. This paper presents a detailed analysis of the average symbol error probability (ASEP) for HQAM over generalized Nakagami-m fading channels. The study considers both integer and non-integer values of the fading parameter m, which models various multipath fading conditions. HQAM is evaluated for its error performance and spectral efficiency relative to conventional QAM formats. Analytical approximations and numerical methods are employed to derive ASEP expressions under diverse fading scenarios. The results indicate that HQAM maintains lower ASEP across a wide signal-to-noise ratio (SNR) range, even in severe fading. This demonstrates its robustness and suitability for deployment in practical wireless systems. The analysis confirms HQAM as a viable alternative for efficient communication over Nakagami-m fading channels. © 2025 IEEE.