Performance of the adaptive rate MQAM with on/off power control

Goldsmith (see IEEE Trans. Commun., vol.45, p.1218-30, 1997) proposed an adaptive rate MQAM with variable power for a higher transmission rate in a fading channel. However, its successful operation requires a highly linear power amplifier to support its variable transmission power. In this paper, to alleviate this requirement, we present an adaptive rate MQAM with on/off power control. The numerical results show that the proposed scheme has a smaller dynamic range of transmission power than the Goldsmith's one and suffers from SNR degradation of about 1.3 dB in terms of spectral efficiency when a set of integer rates is employed.