On-vehicle equipment for dedicated short-range communication in intelligent transport system

• US 20030129952A1
• Filed: 04/03/2002
• Published: 07/10/2003
• Est. Priority Date: 01/09/2002
• Status: Active Grant

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Inoue, Masahiro
• Granted Patent: US 7,062,239 B2
• Time in Patent Office: Days
• US Class Current: 455/95
• CPC Class Codes: H03J 1/0075 where the receiving frequencies of the stations are stored in a permanent memory, e.g. ROM
• CPC Class Codes: H04B 1/28 the receiver comprising at least one semiconductor device having three or more electrodes

Abstract

In an on-vehicle equipment for Dedicated Short-Range Communication (DSRC) in Intelligent Transport System (ITS), a priority sequence for switching local frequencies of f1 to f7 in correspondence with types of on-road equipment is previously set, the local frequencies are sequentially outputted at a predetermined cycle in accordance with the priority sequence, a received frequency signal is compared with a selected frequency signal, and when the received frequency signal is the same as the selection frequency signal, the local frequency corresponding to these is determined as a desirable communication frequency, and the communication frequency is fixed as being this local frequency with high efficiency.

Claims

1. An on-vehicle equipment for Dedicated Short-Range Communication (DSRC) in Intelligent Transport System (ITS) comprising:

a receiving antenna for receiving radio waves sent out of on-road equipments;

a frequency converting unit for converting the frequencies to signal of predetermined frequencies in a plurality of local frequencies;

a channel selecting filter unit for taking only a predetermined channel out of the signal obtained in the frequency converting unit;

a demodulator for digitizing an output from the channel selecting filter unit;

a normal reception determining unit for judging whether or not the radio wave is normally received based on an output from the demodulator;

a PLL oscillating unit for outputting the local frequencies to the frequency converting unit; and

a frequency switching determining means for outputting a selected frequency signal by sequentially switching the local frequencies at a predetermined cycle in accordance with a preset priority sequence of switching the local frequencies in correspondence with types of the on-road equipments.

2. The on-vehicle equipment for DSRC in ITS according to claim 1, wherein the frequency switching determining means is set so as to highly frequently select a frequency of high priority.

3. The on-vehicle equipment for DSRC in ITS according to claim 1, wherein the frequency switching determining means determines the priority sequence of the frequencies based on the vehicle speed.

4. The on-vehicle equipment for DSRC in ITS according to claim 1, wherein the frequency switching determining means is operated under a first control mode of selecting only a frequency or frequencies of high priority and a second control mode of selecting at least a frequency of low priority, and the first control mode is transferred to the second control mode when a switching command is externally inputted.

5. The on-vehicle equipment for DSRC in ITS according to claim 4, wherein the frequency switching determining means returns from the second control mode to the first control mode after a lapse of a predetermined time period from the transfer from the first control mode to the second control mode.