Idle time slot number-based radio frequency label number estimation method and idle time slot number-based radio frequency label number estimation device

The invention is applicable to the technical field of radio frequency identification, and particularly relates to an idle time slot number-based radio frequency label number estimation method and an idle time slot number-based radio frequency label number estimation device. The method includes the following steps: a radio frequency identification reader acquires relative error tolerance, a confidence level and upper and lower label number limits on a radio frequency label set, and works out inquiry rounds, an optimal probability and an optimal frame length; the radio frequency identification reader generates n different random seeds and sends an inquiry instruction carrying the optimal probability, the optimal frame length and the ith random seed to the radio frequency labels of the radio frequency label set; according to respective unique identifiers, the optimal probability, the optimal frame length and the ith random seed, the radio frequency labels of the radio frequency label set calculate random numbers RNG, and reply in the RNGth time slot; the radio frequency identification reader identifies the number of idle time slots obtained from f time slots before the ith round of inquiry; inquiry is carried out for n rounds; and the estimated number of the radio frequency label set is worked out. The invention can prevent the leakage of private data.