A passive entry system is disclosed. The system comprises an unlocking module that performs a key operation in a keyless environment and a plurality of fobs configured to trigger the unlocking module to perform the key operation. each fob has a unique value associated thereto. The unlocking module determines a range of identification values, generates an authentication request packet based on the range, of identification values, and broadcasts the request packet. Each fob receives the request packet; and determines whether the unique identification value of the corresponding fob falls within the range of identification values. The fob also generates a response packet if the unique identification value falls within the range of identification values and transmits the response packet to the unlocking module. The unlocking module receives the response packets from the fobs, and performs the key operation based on one of the received response packets.