Power-delay tradeoff improvement with adaptive modulation scheme under practical power model

In this paper, we focus on the power-delay tradeoff for downlink transmission systems. In particular, we target to design the adaptive modulation scheme that achieves the optimal power-delay tradeoff under practical concerns, such as the practical power consumption model of a base station and the dynamics of user traffic. The optimal modulation level selection problem is formulated in a Markov decision problem and a cross-layer approach is adopted to take both queue and channel dynamics into consideration. Simulation results show that the proposed policy achieves about 20% power saving for the same delay performance, compared with fixed modulation level schemes. In addition, the impact of the practical power consumption model under dynamic traffic does change the optimal modulation level selection philosophy.