Enhancing 5G V2X Mode 2 for Sporadic Traffic
Dmitry Bankov, Artem Krasilov, Artem Otmakhov, Aleksei Shashin, Evgeny Khorov
TL;DR
This work targets the challenge of delivering delay-sensitive and highly reliable DENMs in 5G V2X Mode 2 for sporadic traffic. It introduces three enhancements: Quick First Attempt (QFA) for faster initial resource selection, ideal PSCCH decoding (IPD) via Successive Interference Cancellation, and non-orthogonal full-duplex schemes (SBFD/IBFD). System-level NS-3 simulations show substantial capacity gains, with up to 40% improvement for high-reliability scenarios from QFA, additional gains from IPD up to 20% and 15% under different PLR targets, and up to 35% gains when combining IPD with IBFD, though hardware complexity is a consideration. These results indicate practical pathways to meet stringent QoS in dense vehicular networks, while highlighting tradeoffs between complexity, hardware requirements, and achievable gains.
Abstract
The emerging road safety and autonomous vehicle applications require timely and reliable data delivery between vehicles and between vehicles and infrastructure. To satisfy this demand, 3GPP develops a 5G Vehicle-to-Everything (V2X) technology. Depending on the served traffic type, 5G V2X specifications propose two channel access methods: (i) Mode 1, according to which a base station allocates resources to users, and (ii) Mode 2, according to which users autonomously select resources for their transmissions. In the paper, we consider a scenario with sporadic traffic, e.g., a vehicle generates a packet at a random time moment when it detects a dangerous situation, which imposes strict requirements on delay and reliability. To satisfy strict delay requirements, vehicles use Mode 2. We analyze the performance of Mode 2 for sporadic traffic and propose several approaches to improve it. Simulation results show that the proposed approaches can increase the system capacity by up to 40% with a low impact on complexity.