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.

Device-to-Device (D2D) communications are considered as a keystone of the fifth generation wireless technology (5G). This new approach is very promising in terms of energy and spectrum efficiency. However, the integration of such communications in a typical cellular network increases inevitably the amount of interference. Several researches propose to lower the interference thanks to either sharing the cellular spectrum intelligently, or using non-cellular bands for D2D links. In this paper, we focus on the latter opportunity, and consider that the D2D communications are used with millimeter waves (mmWaves).For what comes to modeling a D2D-enabled (D2D-e) network, many works propose to use stochastic geometry so as to evaluate the impact of interference and noise on the various links. In this work, we aim to analyze the SINR and the average data rate of Outband D2D links for user equipments (UEs) with conventional omnidirectional antennas and with various directional mmWave antennas: patch antennas, horn antennas and uniform linear array antennas.Analytical and empirical evaluations of the Signal-to-Interference-plus Noise Ratio (SINR) are made with stochastic geometry. We propose to discuss the advantages and drawbacks of directional mmWave antennas in Outband D2D for various antenna designs, and their interest in various environments.

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