Patent ID: 8773242

Claim:
An RFID interrogator calculating an adaptive retransmission wait time, comprising: a collision diagnosis unit that analyzes data on a received signal, verifies whether a collision occurs in the received signal, and in response to a determination that a collision has occurred, diagnoses a collision type depending on an analysis result of the data on the received signal; a situational command retransmission portion that determines whether a command will be retransmitted on the basis of the collision type; and in response to the determination that the command will be retransmitted, a random wait time calculation portion calculates a random wait time for retransmitting the command, wherein the random wait time calculation portion randomly selects the random wait time between a minimum retransmission wait time and a maximum retransmission wait time; and the minimum retransmission wait time is calculated by multiplying a wait time parameter by a lower threshold of a retransmission wait threshold value, and the maximum retransmission wait time is calculated by multiplying the wait time parameter by a higher threshold of the retransmission wait threshold value, and the wait time parameter is dynamically changed.