| 摘要 |
PROBLEM TO BE SOLVED: To provide a DSSS compatible optical beacon capable of providing vehicle mounted units with accurate driving safety support information.SOLUTION: The present invention is related to an optical beacon 4 which wirelessly communicates with vehicle mounted devices 2 on traveling vehicles 20 using optical signals. The optical beacon 4 includes; an optical receiver unit 24 having a photo-sensitive element for converting uplink optical signals into electrical signals; an optical transmitter unit 23 having a luminous element for converting electrical signals into downlink optical signals; and a communication control unit (beacon controller) 7 capable of switching to downlink upon reception of one of a plurality of uplink frames UL1, UL2 and generating uplink positions h1, h2. Only upon reception of the uplink frame UL1 that triggers downlink switching, the communication control unit 7 includes uplink positions h1, h2 at the time of the reception in a downlink frame DL2. |
