Abstract
LoRa is based on the chirp spread spectrum (CSS) modulation, which has been developed for low power and long-range wireless Internet of Things (IoT) communications. The structure of LoRa signals makes their decoding performance extremely sensitive to synchronization errors. To alleviate this constraint, we propose a modification of the LoRa physical layer, which we refer to as differential CSS (DCSS), associated with an original synchronization algorithm. Based on this modification, we are able to demodulate the received signals without performing a complete frequency synchronization and by tolerating some timing synchronization errors. Hence, our receiver can handle ultra narrow band LoRa-like signals since it has no limitation on the maximum carrier frequency offset, as is actually the case in the deployed LoRa receivers. In addition, in the presence of the Doppler shift varying along the packet duration, DCSS shows better performance than CSS, which makes our proposed receiver a good candidate for communication with a low-Earth orbit (LEO) satellite.
Highlights
A low power wide area network (LPWAN) is one of the most rapidly growing areas of the communication industry, especially in the Internet of Things (IoT) field
The simulation results we present are obtained from a differential CSS (DCSS) signal simulator that we developed in MATLAB
We proposed a new long range (LoRa)-like receiver, to improve the robustness of symbol decoding to synchronization errors
Summary
A low power wide area network (LPWAN) is one of the most rapidly growing areas of the communication industry, especially in the Internet of Things (IoT) field. According to [1], the share of LPWA connections will grow from about 2.5% in 2018 to. By combining low energy usage, high noise resilience, and long range transmission, LPWANs are promising networks used to bring connectivity that fits the. Both industry and academics are already making significant strides toward a mass IoT solution deployment. Multiple technologies with different physical and MAC layer standards have been defined to address constrained connected object challenges [2]. An ideal example of devices that fall under this category are sensors, used within smart cities, remote sensing, traffic control, supply chains, and so on. LPWAN technologies are accessible to support both licensed and unlicensed spectrum
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