Broadcast reception rates and effects of priority access in 802.11-based vehicular ad-hoc networks
Broadcast reception rates and effects of priority access in 802.11-based vehicular ad-hoc networks
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DOI：
10.1145/1023875.1023878
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发表时间：
2004-10
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影响因子：
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通讯作者：
M. Torrent-Moreno;D. Jiang;H. Hartenstein
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文献类型：
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作者：
M. Torrent-Moreno;D. Jiang;H. Hartenstein
VANET的一个关键用途是支持车辆安全应用。此用例的特征在于广播在缩放设置中的突出性。在这种情况下，我们试图回答以下问题：i）取决于另一辆车与发送者的距离，另一辆车接收广播消息的概率是多少，ii）如何给予优先访问和提高重要警告的接收率，例如，在紧急情况下发出，以及iii）无线电信道衰落引起的信号强度波动如何影响上述两个结果？我们通过模拟量化的概率接收的两射线地面传播模型，以及在饱和环境中的Nakagami分布。通过使用一些IEEE 802.11e EDCA机制的优先级接入，我们不仅量化如何信道接入时间可以减少，但也演示了如何提高接收速率可以实现。我们的研究结果表明，在双向地面模型下的优先访问机制是成功的。然而，对于像Nakagami分布这样的非确定性无线电传播模型，益处仍然是明显的，但是与双射线地面模型相比，接收概率的一般水平要小得多。结果表明，-特别是对于安全关键型和传感器网络类型的应用程序-重复或多跳重传策略的正确设计是未来工作的鲁棒性和网络稳定性的车载自组织网络的一个重要方面。
One key usage of VANET is to support vehicle safety applications. This use case is characterized by the prominence of broadcasts in scaled settings. In this context, we try to answer the following questions: i) what is the probability of reception of a broadcast message by another car depending on its distance to the sender, ii) how to give priority access and an improved reception rate for important warnings, e.g., sent out in an emergency situation, and iii) how are the above two results affected by signal strength fluctuations caused by radio channel fading? We quantify via simulation the probability of reception for the two-ray-ground propagation model as well as for the Nakagami distribution in saturated environments. By making use of some IEEE 802.11e EDCA mechanisms for priority access, we do not only quantify how channel access times can be reduced but also demonstrate how improved reception rates can be achieved. Our results show that the mechanisms for priority access are successful under the two-way-ground model. However, with a non-deterministic radio propagation model like Nakagami's distribution the benefit is still obvious but the general level of probability of reception is much smaller compared to two-ray-ground model. The results indicate that -- particularly for safety-critical and sensor network type of applications -- the proper design of repetition or multi-hop retransmission strategies represents an important aspect of future work for robustness and network stability of vehicular ad hoc networks.