Energy efficient cross-layer transmission design for two-user wireless systems with imperfect channel state information

In this paper, we study a cross-layer transmission design problem in a class of multi-user wireless network. We consider the case that two independent information sources both desire to send two types of delay-sensitive message to a common destination. One type is generated periodically, and is expected to be delivered with sufficient transmission reliability. The other type is generated randomly, and is expected to have finite transmission delay. Utilizing the Lyapunov optimization theory, we design a transmission strategy to achieve high energy efficiency based on both imperfect channel state information (CSI) at the physical layer and queue state information (QSI) at the Media Access Control layer. Simulation results show that the performance of the proposed strategy can be balanced through tuning optimization parameters. The capability of being adaptive to both CSI and QSI also permits the proposed method to outperform the transmission design based on only CSI.