Synchronization and efficient channel hopping for power efficiency in LoRa networks: A comprehensive study

Abstract

The usage of Low-Power Wide Area Networks (LPWAN) is increasing rapidly in many sectors of Internet of Things (IoT) applications. Long Range (LoRa) Wide Area Network (LoRaWAN) is a LPWAN, which has a long-range, low-cost and acts as a connectivity enabler. Most of the applications with real-time requirements, need reliable communication. This can be achieved by sharing a common time base across the network. However, making an efficient collaborative service of clock synchronization in LoRaWAN is challenging due to a lack of time notion. In this paper, We comprehensively study different approaches and design considerations for synchronization and tackle two problems of effective robustness in a LoRaWAN network. First, current research typically focuses on the benefits of LoRaWAN but ignores the requirement of reliability. To tackle this problem, we introduce a novel time synchronization scheme for radically reducing the usage of existing Aloha type protocol that handles energy consumption and service quality. Second, we look into the security space of LoRaWAN network, i.e. channel selection scheme for the given spectrum. Several security attacks are possible in LoRaWAN because the entire spectrum space is not used, and the utilization of few channels are comparatively higher. To tackle this problem, we present a channel hopping scheme that integrates cryptographic channel selection with the time notion. Finally, we evaluate the proposed time synchronization and channel hopping scheme for a real-world deployed peer to peer (P2P) model using commodity hardware. This paper concludes by suggesting the strategic research possibilities on top of this platform.