Patent ID: 6104279
Filing Date: 2000-08-15
Classification: G01S,G06K

Abstract:
A method of communication between a control unit and a plurality of remote units, comprising:for each of the remote units:a) selecting a random period of time and delaying transmission from the remote for said period of time;b) after delaying, transmitting first information from the remote unit to the control unit;c) monitoring for the detection of a transmission from the control unit;d) if a transmission from the control unit is detected during a first window of time subsequent to transmitting the first information, then transmitting second information to the control unit and monitoring for a transmission of one of a first set of commands from the control unit, such a remote unit being referred to as a selected remote unit;e) if a transmission from the control unit is detected prior to or subsequent to the first window of time, then monitoring for the detection of of a second command from the control unit, said second command being exclusive of the first set of commands, such remote units being referred to as unselected remote units;f) if a transmission from the control unit is not detected after an amount of time following the first window of time, then repeating the steps (b)-(f); andg) if the selected remote unit detects a transmission of said second command from the control unit then monitoring for a transmission of a third command from the control unit and responding only to the third command.