Decentralized vehicle-to-everything (V2X) networks (i.e., Mode-4 C-V2X and Mode 2a NR-V2X), rely on periodic Basic Safety Messages (BSMs) to disseminate time-sensitive information (e.g., vehicle position) and has the potential to improve on-road safety. For BSM scheduling, decentralized V2X networks utilize sensing-based semi-persistent scheduling (SPS), where vehicles sense radio resources and select suitable resources for BSM transmissions at prespecified periodic intervals termed as Resource Reservation Interval (RRI). In this paper, we show that such a BSM scheduling (with a fixed RRI) suffers from severe under- and over- utilization of radio resources under varying vehicle traffic scenarios; which severely compromises timely dissemination of BSMs, which in turn leads to increased collision risks. To address this, we extend SPS to accommodate an adaptive RRI, termed as SPS++. Specifically, SPS++ allows each vehicle -- (i) to dynamically adjust RRI based on the channel resource availability (by accounting for various vehicle traffic scenarios), and then, (ii) select suitable transmission opportunities for timely BSM transmissions at the chosen RRI. Our experiments based on Mode-4 C-V2X standard implemented using the ns-3 simulator show that SPS++ outperforms SPS by at least $50\%$ in terms of improved on-road safety performance, in all considered simulation scenarios.
翻译:机动车辆到无障碍(V2X)网络(即模式-4 C-V2X和模式2a NR-V2X)依靠定期的基本安全信息(BSM)来传播时间敏感信息(例如车辆位置),并有可能改善公路安全。对于BSM的时间安排,分散的V2X网络利用基于遥感的半持久性列表(SPS),车辆感知无线电资源,并选择适当的资源资源,用于在预先规定的定期间间间,称为资源保留间隙(RRI),用于BSM的传输。 在本文中,我们表明,这种BSM的时间安排(有固定RRI)在不同的车辆交通情况下,严重不足和过度使用无线电资源(例如车辆位置),从而严重妨碍及时传播BSM,这反过来会增加碰撞风险。为了解决这一问题,我们扩展了卫生和X网络,以适应适应性RRI,称为SP++。 具体地说,SPS+17允许每辆车辆 -- -- (一)根据频道资源供应情况动态对RRI进行动态调整(通过对各种车辆交通情况进行会计核算),然后用我们所选择的RSM-4进行定期试验,利用SMSM标准,根据我们所选择的传输标准,选择的适当传输机会进行适当的传输机会。