LPWAN technologies such as LoRa are widely used for the deployment of IoT applications, in particular for use cases requiring wide coverage and low energy consumption. To minimize the maintenance cost, which can become significant when the number of sensors deployed is large, it is essential to optimize the lifetime of nodes, which remains an important research topic. For this reason, it is necessary that it is based on a fine energy consumption model. Unfortunately, many existing consumption models do not take into account the specifications of the LoRaWAN protocol. In this paper, a refined energy consumption model based on in-situ measurements is provided for a LoRaWAN node. This improved model takes into account the number of nodes in the network, the collision probability that depends on the density of sensors, and the number of retransmissions. Results show the influence of the number of nodes in a LoRaWAN network on the energy consumption of a node and demonstrate that the number of sensors that can be integrated into a LoRaWAN network is limited due to the probability of collision.

One of the key issues with the Internet of Things (IoT) is energy consumption. This type of network is mainly composed of connected objects supplied by an unreliable power source. Wi-Fi HaLow is one of the telecommunication technologies that proposes to connect IoT objects by providing energy optimization mechanisms. It allows the integration of a full IP stack and the implementation of recent security mechanisms. In this article, we introduce power consumption measurements performed on the first device available on the market. In our study, we integrate the current consumed by the power amplifier in transmission phase, and we qualify the power-saving mechanisms. We then propose an analytical model to determine the energy consumed by a sensor node depending on the carried payload. Finally, we validate the use of this technology in IoT application in terms of energy consumption.

IoT networks are more and more present nowadays. Some IoT protocols share the same bandwidth leading to interference on neighboring networks and decrease of overall coverage. To contribute to this problem, an analytical study of the coverage of a LoRa network with underlying uncoordinated IoT networks for uplink transmissions is presented in this paper. Using stochastic geometry, closed form analytical expressions are proposed allowing to analyze the success and coverage probabilities for a LoRa network. An appropriate model of the path loss including real-life values is used to characterize the log-distance propagation parameters. The interference comes from both the LoRa network itself and the underlying IoT networks, modeled with an α-stable distribution based on recent measurements. It is shown that for an environment with a huge amount of surrounding uncoordinated IoT networks, the gateways deployment should be doubled to reach a decent coverage probability, compared to an environment where the underlying interfering networks are not considered.

The deployment of an IoT network is subject to energy consumption constraints. To minimize service costs, it is essential to optimize the lifetime of objects, which are often powered by unreliable energy sources. This optimization must be based on finely-tuned energy consumption models and those generally proposed in the literature do not take into account all the specificities of the transmission of a connected object. In this article, a refined power consumption model based on in-situ measurements is proposed for an 802.11ah station. This improved model takes into account the number of nodes in the network, the number of retransmission attempts and the various exchanges linked to the higher communication layers. The results show the influence of the number of stations in an 802.11ah network on a station’s energy consumption, and demonstrate that the maximum number is limited by the probability of successful transmission.