Piggyback-Based Distributed MAC Optimization for V2X Sidelink Communications

Abstract

Vehicular communications, considered as one of the key technologies for autonomous driving, are still faced with significant challenges, e.g., distributed resource allocation in the direct communication mode. In Cellular Vehicle-to-Everything (C-V2X), a Semi-Persistent Scheduling (SPS) based Medium-Access-Control (MAC) layer protocol is adopted by 3rd Generation Partnership Project (3GPP) for its sidelink communications. However, the performance of either the SPS scheme in standard or the state-of-the-art enhancement works is not satisfactory. In this paper, we propose a piggyback-based collaboration method and firstly introduce Age of Information (AoI) to evaluate the status update performance of C-V2X. In addition, the closed-form AoI performance is obtained. Through extensive simulations, the proposed scheme exhibits better performance than the current schemes, both in terms of AoI and transmission reliability.