User proximity detection for activating vehicle convenience functions

Abstract

A convenience controller activates a small zone high precision welcoming detecting function (with high current utilization) in response to a detected arrival of an authorized user into a larger zone low precision approach region around a vehicle (with low current utilization). A short range transmitter broadcasts a polling signal covering the region. The short range transmitter has an approach pending mode wherein the polling signal is broadcast according to a first repetition and a baseline mode wherein the polling signal is broadcast according to a lower repetition. The short range transmitter has a first power drain in the approach pending mode. A wireless communication system is configured to monitor for user activity outside the approach region corresponding to proximity to the approach region. If the short range transmitter is in the baseline mode when the activity is detected, then the short range transmitter switches to the approach pending mode.