# Accurate Energy Consumption Modeling of IEEE 802.15.4e TSCH Using Dual-Band OpenMote Hardware
## 1 Introduction  
The well-known IoT paradigm is comprised numerous devices that connect to the Internet and contribute to world-wide interconnectivity. Low energy consumption is generally expected of the connected devices, while at the same time being confronted with challenges such as a low expected manufacturing cost, mobility while being connected and deployment in often difficult-to-reach places. This makes minimizing the energy consumption, while still fulfilling strict reliability demands, one of the major challenges of IoT communications.  
To achieve high reliability with minimal power consumption, many research works have been conducted on MAC protocols featuring these requirements [1]. An important development was the IEEE 802.15.4 MAC layer and more specifically the IEEE 802.15.4e MAC amendment that proposed the TSCH mode. TSCH-enabled networks achieve a reliability of 99.999% with minimal power consumption, proving to be a promising solution for wireless industrial networks. TSCH uses channel hopping to improve reliability by minimizing the effects of external interference and multi-path fading. In order to limit the power consumption, it uses a time-synchronized schedule that tells a node exactly when to send and receive data and thus avoids wasting energy during contention periods and idlelistening. The deterministic nature of TSCH scheduling allows for precise modeling of the energy consumption as has been done in the work by [PERSON] et al. [2]. Such a model allows for a detailed energy analysis of new TSCH scheduling functions or new protocols on top of the TSCH MAC layer (e.g., routing protocols), during simulated or real-world experiments.  
In this paper, we propose a novel, more accurate and up-to-date energy consumption model for the IEEE 802.15.4e TSCH mode. It consists of two main contributions. First is a new energy consumption model, based on the work by [PERSON] et al. [2], built from the ground up. It includes a more up-to-date and elaborate set of time slots and states, while using state-of-the-art IoT hardware and firmware. Additionally, the model is extended to support variable packet sizes, a feature absent in the previous work, that allows for a more accurate energy consumption analysis for all packet sizes. As a second contribution, new state durations and state energy consumption measurements are presented for both the 868 MHz and 2.4 GHz frequency bands, using state-of-the-art OpenMote hardware [3, 4]. Moreover, we experimentally verify the accuracy of our model by comparing the calculated values for both the 868 MHz and 2.4 GHz band to the measured values and compare the model to that of [PERSON]. Finally, the new measurements are used to analyze the end-to-end performance of a TSCH network using the official IPv6 over the TSCH mode of IEEE 802.15.4e (6 TiSCH) simulator [5].  
The remainder of this article is structured as follows. In Section 2, we elaborate on TSCH and related work on energy modeling. Subsequently, Section 3 introduces the model itself. In Section 4, the measurement methodology is discussed and the measurement values are presented. Afterwards, the proposed model is evaluated in Section 5 by analyzing calculated values and measured consumption values and comparing the model to a state-of-the-art model. That section also shows the results of the TSCH network simulations to show the energy consumption effects of 868 MHz and 2.4 GHz communication. Finally, Section 6 presents the conclusions of our work.