[Retracted] An XGB-Based Reliable Transmission Method in the mMTC Scenarios

Table 1

Summary of algorithm variables.

Symbol	Description
	The time between the message being sent and the corresponding ACK being received.
	The approximate mean value of historical statistics RTT.
	The smooth factor to SRTT. It is 1/8 on this study.
	The time interval at which data are sent again.
	The smooth factor to . It is 1/4 on this study.
	First RTT measurement value.
	The error between the calculated SRTT of the last data transmission and the real measured RTT.
	The deviation correction between SRTT and real RTT.
	A fixed coefficient in standard TCP is 4.
	The minimum time interval of the timer. It is 100 ms on this study.
	The rate of change in SRTT is 1/3.
	The basic time-out value is 2000 ms in general.
	The random value is between 1.0 and 1.5 in general.
	The max number of retransmission is 4 in general.
	The max time of RTO.
	The rate of change in .