Chinchilla-Romero Natalia, Navarro-Ortiz Jorge, Muñoz Pablo, Ameigeiras Pablo
Department of Signal Theory, Telematics and Communications, University of Granada, 18071 Granada, Spain.
Research Center on Information and Communication Technologies, University of Granada, 18014 Granada, Spain.
Sensors (Basel). 2021 Feb 9;21(4):1218. doi: 10.3390/s21041218.
The number of connected IoT devices is significantly increasing and it is expected to reach more than two dozens of billions of IoT connections in the coming years. Low Power Wide Area Networks (LPWAN) have become very relevant for this new paradigm due to features such as large coverage and low power consumption. One of the most appealing technologies among these networks is LoRaWAN. Although it may be considered as one of the most mature LPWAN platforms, there are still open gaps such as its capacity limitations. For this reason, this work proposes a collision avoidance resource allocation algorithm named the Collision Avoidance Resource Allocation (CARA) algorithm with the objective of significantly increase system capacity. CARA leverages the multichannel structure and the orthogonality of spreading factors in LoRaWAN networks to avoid collisions among devices. Simulation results show that, assuming ideal radio link conditions, our proposal outperforms in 95.2% the capacity of a standard LoRaWAN network and increases the capacity by almost 40% assuming a realistic propagation model. In addition, it has been verified that CARA devices can coexist with LoRaWAN traditional devices, thus allowing the simultaneous transmissions of both types of devices. Moreover, a proof-of-concept has been implemented using commercial equipment in order to check the feasibility and the correct operation of our solution.
联网的物联网设备数量正在显著增加，预计在未来几年将达到超过两千亿个物联网连接。低功耗广域网（LPWAN）由于具有覆盖范围广和功耗低等特点，已与这种新范式高度相关。这些网络中最具吸引力的技术之一是LoRaWAN。尽管它可能被认为是最成熟的LPWAN平台之一，但仍存在一些未解决的问题，比如其容量限制。因此，这项工作提出了一种名为冲突避免资源分配（CARA）算法的冲突避免资源分配算法，目的是显著提高系统容量。CARA利用LoRaWAN网络中的多信道结构和扩频因子的正交性来避免设备之间的冲突。仿真结果表明，假设无线链路条件理想，我们的方案在容量方面比标准LoRaWAN网络高出95.2%，并且在假设实际传播模型的情况下，容量增加了近40%。此外，已经验证CARA设备可以与LoRaWAN传统设备共存，从而允许两种类型的设备同时进行传输。此外，已经使用商业设备实现了概念验证，以检验我们解决方案的可行性和正确运行情况。
