Patent ID: RE45166

Claim:
A method of transmitting vehicle information from a base station mounted in a vehicle to a portable RKE fob via a radio-frequency signal within a specified average field strength limit, said method comprising the steps of: forming a multi-byte vehicle message; coding said vehicle message into a multi-bit coded message; framing said multi-bit coded message into a plurality of packets, wherein each packet corresponds to a respective portion of said vehicle message; wirelessly transmitting said radio-frequency signal from said base station with a plurality of spaced packet windows having a predetermined duty cycle, each packet window including a respective one of said plurality of packets, wherein said radio-frequency signal within each of said packet windows has a predetermined field strength greater than said average field strength limit and a substantially zero field strength between said packet windows, and wherein said predetermined duty cycle results in an actual average field strength for transmitting all of said packets not exceeding said average field strength limit; receiving said plurality of packets within said portable RKE fob; and recovering said vehicle message in response to said received plurality of packets wherein said radio-frequency signal is transmitted within a specified peak field strength limit which is a predetermined decibel level above said average field strength limit, and wherein said predetermined duty cycle corresponds to said predetermined decibel level; and wherein said predetermined duty cycle has a ratio of one-half of a packet window width to a packet period which is substantially equal to a reciprocal of a ratio of said peak field strength limit to said average field strength limit.