Patent ID: 8638195

Claim:
A method comprising: generating at a transponder by random-number-generator circuitry a random number corresponding to a time slot, the random-number-generator circuitry being in an operating mode for generating random numbers, the random-number-generator circuitry being configured in the operating mode as a linear feedback shift register; switching, in response to receiving a selection command from a base station and by clocking of the linear feedback shift register, the random-number-generator circuitry from the operating mode to a counter-operating mode, the random-number-generator circuitry configured in the counter operating mode as a counter, an initial value of a count state of the random-number-generator circuitry in the counter-operating mode being the random number contained in the linear feedback shift register immediately prior to switching the random-number-generator circuitry from the operating mode to the counter-operating mode; modifying, when the random-number-generator circuitry is in the counter-operating mode and in response to receiving a signal corresponding to a start of the time slot from the base station, the count state of the random-number-generator circuitry from the initial value to a modified value; comparing the modified value of the count state of the random-number-generator circuitry to a predetermined value to determine whether to transmit an identification corresponding to the transponder; and transmitting the identification corresponding to the transponder when the modified value of the count state is the predetermined value.