JOINT ADAPTIVE TRANSMISSION AND COMBINING WITH OPTIMIZED RATE AND POWER ALLOCATION

We consider the problem of finding optimal transmission rates and power allocation under the framework of diversity com-bining. Capitalizing on recent results for both link adaptation schemes and adaptive combining, we design and analyze two joint link adaptation and diversity combining schemes. Based on the channel fading, the proposed schemes adaptively se-lect both the signal constellation and diversity combiner struc-ture. We show that the novel schemes provide significant throughput gains compared to existing joint adaptive QAM and diversity schemes. Further, contrary to previous results on power control for discrete rate link adaptation, power con-trol does not give significant average spectral efficiency gains in this jointly adaptive setting. However, power control yields significant outage probability gains over the constant power schemes. 1