LPWC: Long preamble wake-up communication protocol for a LoRa network

LoRa is widely used in various applications, which has gained increasing popularity in the field of Internet of Things (IoT). However, in legacy LoRa protocols, bidirectional communications and low power consumption cannot be achieved simultaneously, hindering the further development of LoRa. In this study, a long preamble wake-up communication (LPWC) protocol is proposed to alleviate the aforementioned issue. This scheme is performed at both sides of communication: (1) LoRa nodes are designed to sleep periodically to save more power; (2) LoRa gateway must send packets with long preamble to maintain the reliability of downlink communication. In addition, an energy model is built to prove that an optimal cycle period exists for LoRa nodes to save more energy. Then we implement simulations to evaluate the performance of the proposed method in various cases. Results show that LPWC outperforms LoRaWAN Class B mode in terms of power conservation and packet latency.