Dynamic Spreading Factor and Power Allocation of LoRa Networks for Dense IoT Deployments
Jaber Babaki, Mehdi Rasti, Rojin Aslani
Abstract
Nowadays, different technologies have been pro-posed for low-power wide-area networks (LPWAN). The long-range wide-area network (LoRaWAN) as one of the LPWAN technologies is designed for the internet of things (IoT) communications which covers thousands of things in a wide range network, with low battery power consumption. The adaptive data rate (ADR) algorithm is a mechanism in LoRaWAN for configuring transmission parameters in a node with the aim of improving the quality of communication between the node and the gateway. Our studies in this paper show that applying the original ADR algorithm in a network with a large number of nodes and in the presence of channel noise results in significantly decreased packet delivery ratio and increased energy consumption. In this paper, we propose an improved version of the original ADR algorithm which dynamically and almost irrespectively of the number of nodes configures transmission parameters including the spreading factor and transmit power of the nodes in LoRa networks with variable channel conditions. In the proposed algorithm, the ordered weighted averaging (OWA) is employed as a decision-making method capable of considering the channel condition in configuring the transmission parameters. Using OWA makes the proposed algorithm perform well at all channel conditions as demonstrated by our numerical results. Also, simulation results show that the packet delivery ratio of the proposed algorithm in a sub-urban scenario with high channel noise is 4 and 1.5 times of the original ADR and other algorithms, respectively, while it consumes the least energy compared to the others.