Adaptive coded-modulation in slow fading channels

The adaptive coded modulation (ACM) is a promising way to provide a substantial improvement in spectral efficiency for slow fading channels. The basic idea is to adapt system functionality such as modulation, coding, information rate, and transmission power to varying channel conditions. In this work, the potential of adaptive coded modulation is investigated using cut-off rate analysis in a unified way and using computer simulation. The analysis includes various effects of fading channels such as feedback delay and channel prediction error. It was shown that the adaptive coded modulation can provide several folds of increase in spectral efficiency compared to a fixed coded-modulation system employing QPSK when channel varies slowly.