As for the problem that the control overhead and transmission delay are large in multi-frame transmission mode between LoRa gateway and LoRa terminal in LoRaWAN protocol, this paper proposed an adaptive multi-frame transmission method, which included adaptive multi-frame sending mechanism, adaptive multi-frame receiving confirmation mechanism and frame loss recognition mechanism. The first mechanism set priority level of the confirmed messages, it made confirm immediately for high-level confirmed messages, and confirmed for low-level confirmed messages uniformly after the end of adaptive sending mode. At the same time, it introduced the Fpending mechanism into LoRaWAN uplink multi-frame transmission. The second mechanism recorded the received message frame information by bit vector compression technology, so as to merge to confirm for multiple confirmed messages once. The third mechanism used the CDID value to identify whether the low-level acknowledgment message was lost, and prevented the terminal from entering the sleep mode abnormally. The mathematical analysis and experimental test results show that, compared to the original mechanism, the AMFET mechanism can effectively reduce data transmission delay and data transmission energy consumption on the premise of guaranteeing the reliability of data transmission.

[2020-05-05] Printed Article /doc/2018.11.0840/v2