# Energy Consumption Analysis of LPWAN Technologies and Lifetime Estimation for IoT Application
## 2 Related Work  
Energy efficiency is the key requirement for any sensor based application. LPWAN technologies are relatively new and are used in both indoor and outdoor applications [7; 8]. Several papers have explored and evaluated the energy consumption of different individual LPWAN technologies [9; 10; 11]. Driven by the challenges of energy depletion, many recent works have focused to increase the power efficiency of the network and reduce the power dissipation in communication. [PERSON] et al. [12], did a comparative study between different low power wireless technologies and demonstrate the choice of right protocol is vital for the battery life. Data rate and payload affect the power consumption, so it should be contemplated prior to selecting the protocol. [PERSON] et al. [13], proposed an approach for calculating energy effectiveness based on throughput and identification of energy-efficiency among existing cross over models. The paper on the comparative study of LPWAN technologies [5; 8] shows that LoRaWAN and Sigfox are advantageous in terms of battery lifetime as compared with NB-IoT. Author [PERSON] et al. [14], raises energy-efficiency as a challenge for LPWAN networks which demands better design techniques. Network parameters are the key pillar for the performance and the network lifetime. Paper [15], formulates and demonstrates the impact of network parameters on energy efficiency. In addition to the analysis, it states battery lifetime as a function of LPWAN transmission parameters. There are contributions in developing custom hardware for LPWAN [16] to optimize the key constraints of hardware design i.e cost and energy. Many published works focus on technology-specific energy modeling and performance evaluation mainly on coverage, capacity, and energy consumption. The papers [11; 17], present an analytical model to characterize the current composition, device lifetime, and cost of the delivery of each message. It also gives the theoretical lifetime of the battery while sending messages at a particular interval, maintaining the duty cycle. In the same context, [PERSON] [9] did the modeling for the energy performance of LoRaWAN. Evaluation results from this paper claim to achieve one year lifetime with  
Figure 2: LPWAN common architecture featuring key elements and connectivity. an appropriately configured LoRaWAN end-device. However, as LPWAN protocol are very similar to Aloha type so its energy performance needs better design scheme such as time synchronization [18; 19]. [PERSON] et al. [20] describes the energy consumption model estimating consumed power in each sensor element. LoRaWAN provides three different device classes, which has different performance and energy consumption. [PERSON] et al. [21] did the theoretical and experimental comparison of the LoRaWAN classes and proclaims the operational battery life of ten years with Class A device, considering that parameters are correctly configured. LoRaWAN is used for both indoor and outdoor monitoring. Paper [22], used LoRaWAN for indoor human-centric applications and did the power consumption to illustrate the importance of radio operation mode and the use of the adaptive data rate for power efficiency. Paper [10] presents an energy consumption model for NB-IoT devices using Power Saving Mode (PSM) and Extended Discontinuous Reception (eDRX), with a Poisson arrival process for uplink and downlink data transmissions. [PERSON] et al. [23], surveyed on energy-efficient NB-IoT architecture and also proposed energy efficient approach for applications like agriculture and healthcare. In another tag collection application [24], the evaluation of DASH7 shows that it has better performance than slotted Aloha. For energy efficiency, application-specific parameters plays an crucial role and on top of it energy harvesting is done [25] to prolong the battery life. Most of the aforementioned published papers have done the technology specific evaluation and analysis.