Adaptive Modulation Systems Subject to Interference

Adaptive modulation techniques enable wireless systems to achieve high spectral efficiency (SE) while maintaining a target quality of service and are rising a great interest for high data rate communications in fading channels. In this paper, we analyze slow adaptive M-ary quadrature amplitude modulation systems with diversity subject to interference. We derive the performance in terms of mean SE and bit error outage for systems experiencing co-channel interference with optimum combining. The analysis leads to a new definition of in-service regions, to be used for the optimum constellation size selection in place of signal-to-noise ratio thresholds