Pavlova Irina, Bankov Dmitry, Khorov Evgeny, Lyakhov Andrey
Institute for Information Transmission Problems of the Russian Academy of Sciences, 127051 Moscow, Russia.
Sensors (Basel). 2023 Nov 8;23(22):9054. doi: 10.3390/s23229054.
NB-Fi (Narrow Band Fidelity) is a promising protocol for low-power wide-area networks. NB-Fi networks use license-exempt Industrial, Scientific, and Medical (ISM) bands and, thus, NB-Fi devices can work in two modes: with and without Listen Before Talk (LBT). This paper compares these modes with different implementations of LBT in terms of packet loss rate (PLR), delay, energy consumption, and throughput. Interestingly, in some scenarios, the results contradict expectations from the classic papers on channel access because of the peculiarities of the NB-Fi technology. These contradictions are explained in the paper. The results show that LBT can significantly improve all the considered performance indicators when the network load exceeds 40 packets per second. With extensive simulation, we show that in a small NB-Fi network, the optimal PLR, delay, and energy consumption are obtained with the implementation of LBT that corresponds to non-persistent CSMA. In a large NB-Fi network, where some devices can be hidden from others, the best strategy to improve PLR, delay, throughput, and energy consumption is to use the implementation of LBT that corresponds to p-persistent CSMA.
窄带保真（NB-Fi）是一种适用于低功耗广域网的很有前景的协议。NB-Fi网络使用免许可的工业、科学和医疗（ISM）频段，因此，NB-Fi设备可以在两种模式下工作：有和没有先听后说（LBT）功能。本文从丢包率（PLR）、延迟、能耗和吞吐量方面，将这些模式与LBT的不同实现方式进行了比较。有趣的是，在某些场景中，由于NB-Fi技术的特性，结果与关于信道接入的经典论文中的预期相矛盾。本文对这些矛盾进行了解释。结果表明，当网络负载超过每秒40个数据包时，LBT可以显著改善所有考虑的性能指标。通过广泛的仿真，我们表明，在小型NB-Fi网络中，采用对应于非持续CSMA的LBT实现方式可获得最佳的PLR、延迟和能耗。在大型NB-Fi网络中，一些设备可能会对其他设备隐藏，提高PLR、延迟、吞吐量和能耗的最佳策略是使用对应于p-持续CSMA的LBT实现方式。
