Patent ID: 6337978
Filing Date: 2002-01-08
Classification: H04W,Y02D

Abstract:
A dedicated short-range communication mobile device for intelligent transport systems comprising:an antenna; a data transmission/reception circuit for transmitting and receiving data to and from a ground device through said antenna; a first discrete power supply circuit for supplying power to said data transmission/reception circuit; received electric field strength detecting means for measuring a power level of a radio wave from the ground device received through said antenna; communication area detecting means for recognizing, as a communication area, an area in which the power level of the radio wave from the ground device exceeds a predetermined value based on an output of said received electric field strength detecting means; power supply starting means for starting said first discrete power supply circuit based on an output of said communication area detecting means; and a second discrete power supply circuit for supplying power to said received electric field strength detecting means, said communication area detecting means and said power supply starting means.