Lai Lianyou, Song Zhongzhe, Xu Weijian
School of Ocean Information Engineering, Jimei University, Xiamen 361000, China.
Sensors (Basel). 2024 Feb 3;24(3):992. doi: 10.3390/s24030992.
The capture effect is a frequently observed phenomenon in vehicular ad hoc networks (VANETs) communication. When conflicts arise during time slot access, failure to access does not necessarily occur; instead, successful access may still be achieved. The capture effect can enhance the likelihood of multiple access and improve communication efficiency. The security of VANETs communication is undoubtedly the primary concern. One crucial approach to enhance security involves the design of an efficient and reliable medium access control (MAC) protocol. Taking into account both aspects, we propose a novel framed slotted Aloha (FSA) MAC protocol model. Firstly, we derive the closed-form expression for the capture probability in the Rician fading channel in this paper. Subsequently, we analyze how the number of vehicles and time slots influence the success probability of vehicle access channels as well as examine the impact of the capture effect on this success probability. Then, under constraints regarding vehicle access channel success probability, we derive optimal values for slot numbers, access times, and transmission power while proposing a comprehensive implementation method to ensure high access channel success probabilities. We verify both theoretical derivations and proposed methods through simulation experiments.
捕获效应是车载自组织网络（VANETs）通信中经常观察到的一种现象。当时隙接入期间发生冲突时，不一定会出现接入失败；相反，仍有可能成功接入。捕获效应可以提高多址接入的可能性并提高通信效率。VANETs通信的安全性无疑是首要关注点。增强安全性的一种关键方法涉及设计高效可靠的介质访问控制（MAC）协议。考虑到这两个方面，我们提出了一种新颖的帧时隙Aloha（FSA）MAC协议模型。首先，本文推导了瑞利衰落信道中捕获概率的闭式表达式。随后，我们分析车辆数量和时隙如何影响车辆接入信道的成功概率，并研究捕获效应对此成功概率的影响。然后，在车辆接入信道成功概率的约束条件下，我们推导时隙数、接入时间和发射功率的最优值，同时提出一种全面的实现方法以确保高接入信道成功概率。我们通过仿真实验验证了理论推导和所提出的方法。
