ASER Analysis of Hexagonal and Rectangular QAM Schemes in Multiple-Relay Networks

In this paper, analytical lower bound expressions of average symbol error rate (ASER) for general-order hexagonal quadrature amplitude modulation (QAM) and rectangular QAM (RQAM) schemes are derived for multiple amplify-and-forward relay networks over independent and nonidentically distributed Nakagami-m fading channels with an integer-valued fading parameter using a well-known cumulative-distribution-function-based approach. Furthermore, ASER expressions for 32-cross QAM, differentially encoded quadriphase shift keying (QPSK), and pi/4-QPSK modulation schemes are derived for the considered systems. The asymptotic ASER expression is also derived for the RQAM scheme, which is useful to examine system's diversity order. Numerically evaluated results are verified by Monte Carlo simulation.