A Reliable Self-Adaptive Scheduling Control Protocol for Cellular V2X Mode 4

The rapid development and deployment of the Cellular V2X (C-V2X) require a highly reliable support system for many vehicular key applications. However, the current standard sensing-based semi-persistent scheduling (SB-SPS) protocol yields poor performance in terms of reliability, due to the hidden terminal problem and the half-duplex issue. In this paper, we propose a reliable self-adaptive MAC protocol for C-V2X Mode 4 (autonomous sidelink). It utilizes frame information and RSSI to exclusively scheduling resource blocks in two-hop neighbors, and dynamically adjusts scheduling and frame length according to changes of the network environment. Simulation results show that the proposed protocol achieves significantly higher PDR and lower number of the packet collisions than SB-SPS and IEEE 802.11p.