Yassine Farah, El Helou Melhem, Lahoud Samer, Bazzi Oussama
Ecole Doctorale des Sciences et Technologies, Lebanese University, Hadath 11-8281, Lebanon.
Ecole Supérieure d'Ingénieurs de Beyrouth, Saint Joseph University of Beirut, Beirut 111, Lebanon.
Sensors (Basel). 2022 Oct 12;22(20):7744. doi: 10.3390/s22207744.
This paper presents a detailed study of uplink scheduling in narrowband internet of things (NB-IoT) networks. As NB-IoT devices need a long battery lifetime, we aim to maximize energy efficiency while satisfying the main requirements for NB-IoT devices. Also, as the NB-IoT scheduling problem is divided into link adaptation problem and resource allocation problem, this paper investigates the correlation between these two problems. Accordingly, we propose two scheduling schemes: the joint scheduling scheme, where the two problems are combined as one optimization problem, and the successive scheduling scheme that manages each problem separately but successively. Each scheme aims to maximize energy efficiency while achieving reliable transmission, satisfying delay requirements, and guaranteeing resource allocation specifications. Also, we investigate the impact of the selected devices to be served on the total energy efficiency. Accordingly, we propose two device selection techniques to maximize the total energy efficiency. The first technique exhaustively searches for the optimal devices, while the second sorts the devices based on a proposed priority score. The simulation results compare the successive and the joint scheduling schemes. The results show that the joint scheme outperforms the successive scheme in terms of energy efficiency and the number of served devices but with higher complexity. Also, the results highlight the impact of each proposed selection technique on the scheduling schemes' performance.
本文对窄带物联网（NB - IoT）网络中的上行链路调度进行了详细研究。由于NB - IoT设备需要较长的电池续航时间，我们旨在在满足NB - IoT设备主要需求的同时，最大化能源效率。此外，由于NB - IoT调度问题分为链路适配问题和资源分配问题，本文研究了这两个问题之间的相关性。相应地，我们提出了两种调度方案：联合调度方案，即将这两个问题合并为一个优化问题；以及连续调度方案，即分别但连续地处理每个问题。每种方案都旨在在实现可靠传输、满足延迟要求并保证资源分配规范的同时，最大化能源效率。此外，我们研究了所选服务设备对总能源效率的影响。相应地，我们提出了两种设备选择技术以最大化总能源效率。第一种技术穷举搜索最优设备，而第二种技术根据提出的优先级分数对设备进行排序。仿真结果对连续调度方案和联合调度方案进行了比较。结果表明，联合方案在能源效率和服务设备数量方面优于连续方案，但复杂度更高。此外，结果突出了每种提出的选择技术对调度方案性能的影响。
