The Society of Automotive Engineers (SAE) has specified a wireless channel congestion control algorithm for cellular vehicle-to-everything (C-V2X) communication in J3161/1. A notable aspect of J3161/1 standard is that it addresses persistent packet collisions between neighboring vehicles. Although the chances are slim, the persistent collisions can cause so called the wireless blind spot once the event takes place. Then the involved vehicles cannot inform their presence to neighboring vehicles, an extremely dangerous condition for driving safety. J3161's solution to the problem is stochastic one-shot transmission, where the transmission occasionally occurs in a resource that is not originally reserved. Through the one-shot transmission, the worst-case packet inter-reception time (PIR) is bounded and the wireless blind spot problem can be effectively mitigated. Interestingly, the standard one-shot transmission scheme does not resolve the persistent collision relation itself. This paper shows that by breaking out of the relation as soon as the persistent collision condition is identified, vehicles can improve the worst-case PIR by approximately 500 ms, the number of packet collisions per persistent collision event by 10%, and the number of total collisions by 15% to 57% over the standard one-shot transmission.

翻译：美国汽车工程师学会（SAE）在J3161/1标准中规定了蜂窝车联网（C-V2X）通信的无线信道拥塞控制算法。该标准的一个显著特点是针对相邻车辆间的持续性数据包碰撞问题。尽管发生概率较低，但一旦出现持续性碰撞，将导致所谓的"无线盲区"现象。此时相关车辆无法向周边车辆通报自身存在，这对行车安全构成极端危险。J3161的解决方案采用随机单次传输机制——即在非原始预留的资源上偶尔进行数据发送。通过单次传输，最坏情况下的数据包接收间隔时间（PIR）得到有效约束，无线盲区问题可被显著缓解。值得注意的是，标准单次传输方案本身并未消除持续性碰撞关系。本文证明，通过在检测到持续性碰撞条件后立即解除该碰撞关系，车辆可将最坏情况下的PIR改善约500毫秒，每次持续性碰撞事件中的数据包碰撞次数减少10%，总碰撞次数较标准单次传输方案降低15%至57%。