Patent ID: 9035748
Filing Date: 2015-05-19
Classification: G06K,H04W

Abstract:
1. An RFID interrogator, comprising; a transmit circuit configured to generate transmit data; a receive circuit configured to decode receive data; a collision detection circuit configured to compare the transmit data with the receive data; a processor coupled with the transmit circuit and the receive circuit, the processor configured to execute instructions; and a memory coupled with the processor, the memory configured to store instructions, the instructions configured to cause the processor to: enter a quiet state during which the processor prevents the transmit circuit from generating the transmit data, select a first transmit time after the quiet state during which the interrogator will attempt to transmit a first set of transmit data via the transmit circuit, return to the quiet state if the receiver detects data on its receive path prior to the first transmit time and select a new first transmit time, transmit the first set of transmit data during the first transmit time or the new first transmit time when the receiver does not detect data on its receive path prior to the first transmit time or the new first transmit time, return to the quiet state when the collision detection circuit detects that the receive path does not match the transmit path after the first set of transmit data is transmitted, wait a predetermined period of time different than the quiet state when the collision detection circuit does not detect that the receive path does not match the transmit path after the first set of transmit data is transmitted, select a second transmit time after the first set of transmit data has been transmitted during which the interrogator will attempt to transmit a second set of transmit data via the transmit circuit, return to the quiet state if the receiver detects data on its receive path prior to the second transmit time, transmit the second set of transmit data during the second transmit time, and return to the quiet state when the collision detection circuit detects that the receive path does not match the transmit path after the second set of transmit data is transmitted.