Short range radio continuous communication method and system

• US 20020047786A1
• Filed: 10/12/2001
• Published: 04/25/2002
• Est. Priority Date: 10/25/2000
• Status: Active Grant

• Current Assignee: NEC Corporation
• Original Assignee: NEC Corporation
• Inventors: Kasagi, Ken
• Granted Patent: US 6,861,958 B2
• Time in Patent Office: Days
• US Class Current: 340/928
• CPC Class Codes: G08G 1/096716 where the received information does not generate an automatic action on the vehicle control
• CPC Class Codes: G08G 1/096758 where no selection takes place on the transmitted or the received information
• CPC Class Codes: G08G 1/096783 where the origin of the information is a roadside individual element

Abstract

To obtain a communication method which makes it possible to perform continuously communication through roadside antennas alternately arranged for a time sharing operation. Roadside antennas are arranged so that communication ranges are suitably overlapped for making the time sharing operation possible, and an on-vehicle device searches a communication frame from an adjacent next antenna during the communication with one of the roadside antennas at the overlapping point, and in the case where an FCMS can continuously be received, a switching from the communicating antenna to the adjacent antenna is instantaneously performed to make it possible to continue the communications between the roadside devices and the on-vehicle device.

Claims

1. A short range radio communication method, in which a DSRC (Dedicated Short Range Communication) that is a short range radio communication used for an ETC (Electronic Toll Collection) that is a non-stop toll collection system is applied, and roadside antennas that are provided at a roadside are continuously arranged, and time sharing operation is performed by synchronizing sending timing of a communication frame in all of said roadside antennas, comprising:

a step for receiving a communication frame transmitted from an adjacent roadside antenna during the communication with one of said roadside antennas in an on-vehicle device which is a radio set mounted on a vehicle and performs the communication with said roadside antennas.

2. The short range radio communication method according to claim 1,

wherein said step comprises:

an FCMS detecting step for detecting an FCMS (Frame Control Message Slot) of the communication frame transmitted from said adjacent roadside antenna at stopping timing of the communicating roadside antenna; and

a step for switching the communication from the communicating roadside antenna to the adjacent roadside antenna on the basis of results detected by said FCMS detecting step.

3. The short range radio communication method according to claim 1,

wherein said roadside antennas are continuously arranged so that part of the effective communication range of each of said roadside antennas is overlapped onto the effective communication range of the adjacent roadside antenna, and said step is performed when said on-vehicle device exists in an overlapped part of said effective communication ranges.

4. The short range radio communication method according to claim 1, further comprising a DSRC control step for performing DSRC protocol processing in each of roadside devices, provided corresponding to said roadside antennas,

wherein said time sharing operation is performed by practicing synchronization among all DSRC control steps.

5. A short range radio communication system, in which a DSRC (Dedicated Short Range Communication) that is a short range radio communication used for an ETC (Electronic Toll Collection) that is a non-stop toll collection system is applied, and roadside antennas that are provided at a roadside are continuously arranged, and time sharing operation is performed by synchronizing sending timing of a communication frame in all of said roadside antennas, comprising:

an on-vehicle device which is a radio set mounted on a vehicle and performs the communication with said roadside antennas, wherein said on-vehicle device includes means for receiving a communication frame transmitted from an adjacent roadside antenna during the communication with one of said roadside antennas.

6. The short range radio communication system according to claim 5,

wherein said means comprises:

FCMS detecting means for detecting an FCMS (Frame Control Message Slot) of the communication frame transmitted from said adjacent roadside antenna at stopping timing of the communicating roadside antenna; and

means for switching the communication from the communicating roadside antenna to the adjacent roadside antenna on the basis of results detected by said FCMS detecting means.

7. The short range radio communication system according to claim 5,

wherein said roadside antennas are continuously arranged so that part of the effective communication range of each of said roadside antennas is overlapped onto the effective communication range of the adjacent roadside antenna, and said means receives the communication frame from the adjacent roadside antenna when said on-vehicle device exists in an overlapped part of said effective communication ranges.

8. The short range radio communication system according to claim 5,

wherein each of roadside devices provided corresponding to said roadside antennas includes a DSRC control section for performing DSRC protocol processing, and said time sharing operation is performed by practicing synchronization among all DSRC control sections.

9. The short range radio communication system according to claim 5,

wherein the communication contents which are concurrently taken in a communication frame from the communicating roadside antenna and a communication frame from the adjacent roadside antenna are mutually different communication contents.