Cross-Layer Joint Scheduling for D2D Communication in Cellular Systems

The introduction of device-to-device (D2D) communications into cellular system can improve spectrum efficiency and reduce traffic load of the core network, but it can also increase the scheduling complexing at the base station (BS). Hence designing an efficient scheduling algorithm has become a hot topic for developing D2D communications in cellular systems. But most existing work on the scheduling algorithm commonly assume that all the channel state information (CSI) are known at the BS, i.e., the BS can obtain all the CSI that it needs to perform scheduling, but the scheduling algorithms designed based on the assumptions usually corresponds to a very high overhead on channel measurement when they are implement into actual systems. With this background, a cross-layer joint scheduling scheme that can jointly perform power coordination, channel allocation for D2D capable users by taking into account both the transmission rate criteria of physical layer and the transmission delay criteria of link layer under the condition that the CSI are partly known at the BS are proposed, also the supported D2D mode for D2D-capable users in the cellular system is only the reuse direct D2D mode. Meanwhile, according to the channel probability and statistical characteristics for the interference channels, the end-to-end transmission delay estimation method for the reuse direct D2D mode is presented. Simulation results validate the effectiveness of the joint scheduling scheme and the increase of the system performance brought in the reuse direct D2D mode, in addition, the influence of the major system parameters of the performance on the joint scheduling scheme are also analyzed.