Low Power Wide Area Networks: A Survey of Enabling Technologies, Applications and Interoperability Needs <s> 2) SigFox <s> Internet of Things (IoT) technology has attracted much attention in recent years for its potential to alleviate the strain on healthcare systems caused by an aging population and a rise in chronic illness. Standardization is a key issue limiting progress in this area, and thus this paper proposes a standard model for application in future IoT healthcare systems. This survey paper then presents the state-of-the-art research relating to each area of the model, evaluating their strengths, weaknesses, and overall suitability for a wearable IoT healthcare system. Challenges that healthcare IoT faces including security, privacy, wearability, and low-power operation are presented, and recommendations are made for future research directions. <s> BIB001 </s> Low Power Wide Area Networks: A Survey of Enabling Technologies, Applications and Interoperability Needs <s> 2) SigFox <s> Abstract By 2020, more than 50 billion devices will be connected through radio communications. In conjunction with the rapid growth of the Internet of Things (IoT) market, low power wide area networks (LPWAN) have become a popular low-rate long-range radio communication technology. Sigfox, LoRa, and NB-IoT are the three leading LPWAN technologies that compete for large-scale IoT deployment. This paper provides a comprehensive and comparative study of these technologies, which serve as efficient solutions to connect smart, autonomous, and heterogeneous devices. We show that Sigfox and LoRa are advantageous in terms of battery lifetime, capacity, and cost. Meanwhile, NB-IoT offers benefits in terms of latency and quality of service. In addition, we analyze the IoT success factors of these LPWAN technologies, and we consider application scenarios and explain which technology is the best fit for each of these scenarios. <s> BIB002
SigFox [40] is another proprietary LPWA solution that operates in the 200 kHz band of the publicly available spectrum to transfer 100 Hz wide messages at a data rate of 100 bps or 600 bps. Using UNB modulation, SigFox achieves a range between 10 and 50 km and robustness against noise. The maximum payload sizes for UL and DL are 12 and 8 bytes, respectively. Thus, a message is expected to take only a short time (an average of 2 s) to reach the base station. Due to the small message size and a restriction on the number of packets per day, this solution requires less energy, consequently prolonging the battery life of devices. Each device is limited to a maximum of 140 UL messages and 4 DL messages under the strictest regulations BIB002 , BIB001 . SigFox relies on the cloud for computing and pushes the network complexity to the base station to achieve affordable and energy-efficient devices. Unlike in cellular protocols, a SigFox device can connect to any of the three base stations in its range. The resistance of SigFox to interference is based on the implementation of three different diversity schemes: time, frequency, and space [40] .