Lora message reloading exception handling method, sending end and receiving end

A Lora message reload exception handling method comprise a sending end and a receiving end. The method comprises the following steps: after sending the last reloading request message, the sending endstarts a timeout timer and waits for the piece-wise reloading confirmation message of the receiving end; if the timer does not time out and the fragment reloading confirmation message is received, thefragment sending ends; if the timer expires and the fragment reloading acknowledgement message of the receiving end is not received and the fragment reloading request message is not received, the fragment transmission is deemed to be failed, the fragment is discarded, and the fragment transmission result is returned to exit the transmission. The receiving end resets the timeout time of the timeout timer after receiving a fragmentation or reloading request message every time. If the fragmentation reloading is not completed after a period of timeout, the receiving end sends a fragmentation reloading failure message, the