Patent ID: 9685014
Date: 2017-06-20
CPC Classifications: G07C,H04W

Claim:
1. A method comprising: detecting, by a base station of a vehicle, whether the vehicle is in a key on vehicle state, an accessory mode vehicle state, or a key off vehicle state; selecting, at the base station, a LF sinusoidal carrier wave in response to the vehicle being either in the key on vehicle state or the accessory mode vehicle state, the LF sinusoidal carrier wave having a carrier frequency falling within a range of 20 kHz to 300 kHz; generating, at the base station, a first LF polling signal including a wakeup message and the LF sinusoidal carrier wave; transmitting, from an antenna of the base station, while the vehicle is either in the key on vehicle state or the accessory mode vehicle state the first polling signal for receipt by a portable controller; selecting, at the base station, a LF non-sinusoidal periodic carrier wave in response to the vehicle being in the key off vehicle state, the LF non-sinusoidal periodic carrier wave having a carrier frequency falling within a range of 20 kHz to 300 kHz; generating, at the base station, a second LF polling signal including a wakeup message and the LF non-sinusoidal periodic carrier wave; and periodically transmitting, from the antenna of the base station, while the vehicle is in the key off vehicle state the second polling signal during an absence of a user touching the vehicle until a portable controller responds to the second LF polling signal.