US 7,551,057 B2
	Remote entry system with increased transmit power and reduced quiescent current
Ronald O. King, Brownstone, Mich. (US); Neal Richard Manson, Southfield, Mich. (US); and Steven Chang, Clinton Township, Mich. (US)
Assigned to Lear Corporation, Southfield, Mich. (US)
Filed on Nov. 04, 2005, as Appl. No. 11/266,933.
Prior Publication US 2007/0103271 A1, May 10, 2007
Int. Cl. B60R 25/00 (2006.01)

U.S. Cl. 340—5.72  [340/426.13; 340/5.64; 340/442; 340/10.1; 340/825.69]

10 Claims

1. A method of operating a remote entry system for a vehicle, said remote entry system including a portable transmitter and a vehicle-mounted receiver, said method comprising the steps of: alternating said receiver between a monitoring state lasting for a monitoring period and a sleep state lasting for a sleep period, said monitoring period and said sleep period together comprising a cycle period; manually activating said remote control; and transmitting a message sequence to said receiver in response to said manual activation for initiating a function of said remote entry system, said message sequence comprising a plurality of blocks transmitted at a predetermined block interval, said blocks including a preamble block and at least one message block, wherein if said receiver detects said preamble block then it enters a reception state for detecting said message block; wherein said preamble block has a predetermined preamble length and is comprised of a plurality of bytes separated by respective off intervals between successive bytes, wherein each byte comprises a predetermined byte period, wherein each off interval comprises a predetermined off period greater than said predetermined byte period, wherein said predetermined off period is less than said monitoring period, and wherein said monitoring period is less than or equal to said predetermined off period plus twice said predetermined byte period.