Performance Analysis of Angle Modulated MQAM Transmission Techniques

We introduce a novel method of digital modulation with a high spectral efficiency, called the angle (exponentially) modulated m-ary quadrature amplitude modulation (EM-MQAM). The main advantage of EM-MQAM is an ability to transmit a multilevel 2-D MQAM constellation as a constant envelope signal. It makes EM-MQAM a preferred technique for application in multipath fading channel since no amplitude discrimination in the receiver is needed. The transmission bandwidth and BER performance of EM-MQAM have been analyzed. Despite of the fact that EM-MQAM requires as twice as much of the transmit bandwidth compared to the conventional MQAM, it provides reasonable trade-off between transmit bandwidth and BER performance. Furthermore, EM-MQAM requires just 1 dB of extra transmit power if the order of original MQAM increases fourfold.