Energy minimization is an important goal in wireless communication system design, and cross-layer optimization is an available approach by optimizing parameters in different layers of OSI model, thus, the system could be energy efficient. In many state-of-the-art communication transceivers, RF and analog section can consume more energy compared to the digital part. In this paper, we establish a system level accurate energy consumption model of main transceiver components first with MQAM and MPSK modulation respectively; analysis the relationship between PHY parameters and MAC parameters, then, a cross-layer optimization method for energy-efficient design is proposed. Simulation results reveal that adaptive modulation...