FQAM : A modulation scheme for beyond 4G cellular wireless communication systems

We analyze the performance of bit interleaved coded modulation (BICM) and coded modulation (CM) systems with frequency and quadrature amplitude modulation (FQAM), which is a combination of frequency shift keying (FSK) and quadrature amplitude modulation (QAM). Numerical results show that for modest code rates in low signal-to-noise ratio regions, the normalized throughputs of FQAM based CM systems are close to the theoretical channel capacity limit compared to that of QAM and FSK based CM systems. Also, we analyze the performance of downlink cellular LTE systems using FQAM and compare it with that using QAM, especially for cell-edge users. Numerical results show that, unlike QAM, the statistical distribution of inter-cell interference (ICI) incurred with FQAM highly deviates from the Gaussian distribution and has a heavier tail. The results also show that due to the non-Gaussian nature of the ICI incurred with FQAM, the transmission rate of a cell-edge user using FQAM is significantly higher than that using QAM.