In-vehicle radio apparatus

• US 20050168350A1
• Filed: 01/18/2005
• Published: 08/04/2005
• Est. Priority Date: 01/22/2004
• Status: Active Grant

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Tauchi, Nobutaka
• Granted Patent: US 7,342,509 B2
• Time in Patent Office: Days
• US Class Current: 340/903
• CPC Class Codes: G08G 1/161 Decentralised systems, e.g. inter-vehicle communication

Abstract

In an in-vehicle radio apparatus to radio-transmit information from a vehicle about to enter an intersection, the interference between a radio signal transmitted from the vehicle and a radio signal transmitted from another vehicle is suppressed. Further, an approach direction of the vehicle to the intersection can be accurately transmitted. In the radio apparatus to transmit a radio signal by using a spread spectrum method, it is determined that the vehicle has approached a first distance from the intersection, and based on the determination, a spread code corresponding to an approach direction of the vehicle to the intersection is allocated as a spread code used for transmission.

Claims

1. An in-vehicle radio apparatus comprising:

a transmission unit for transmitting a radio signal by using a spread spectrum method;

a first approach determination unit for determining that a vehicle has entered a first distance from an intersection; and

an allocation unit for allocating a spread code corresponding to an approach direction of the vehicle to the intersection as a spread code used for transmission by the transmission unit based on determination by the first approach determination unit.

2. The in-vehicle radio apparatus according to claim 1,

wherein the allocation unit specifies the spread code corresponding to the approach direction of the vehicle to the intersection based on a traveling direction of the vehicle, and correspondence data between approach directions to a particular intersection and spread codes.

3. The in-vehicle radio apparatus according to claim 2,

wherein in the correspondence data, regarding continuous multiple intersections, the same spread code corresponds to a direction continuously passing the multiple intersections along a road.

4. The in-vehicle radio apparatus according to claim 2,

wherein in the correspondence data, regarding continuous multiple intersections at standard or shorter intervals, the same spread code corresponds to a direction continuously passing the multiple intersections along a road.

5. The in-vehicle radio apparatus according to claim 2,

wherein in the correspondence data, a spread code in a particular approach direction to a particular intersection corresponds to a transmission end position of transmission with the spread code, and

wherein the in-vehicle radio apparatus further comprises a transmission termination control unit for, when the transmission unit transmits a radio signal with a spread code allocated by the allocation unit regarding an approach direction to an intersection, terminating transmission with the spread code by the transmission unit based on passage of the vehicle across a transmission end position corresponding to the spread code for the approach direction to the intersection of the correspondence data.

6. The in-vehicle radio apparatus according to claim 5,

wherein in the correspondence data, regarding continuous multiple intersections, the same spread code corresponds to a direction continuously passing the multiple intersections along a road, and a transmission end position corresponding to the same spread code is a position of a last intersection upon passing of the continuous multiple intersections along the road.

7. The in-vehicle radio apparatus according to claim 2,

wherein regarding a five-forked or more-forked intersection, the correspondence data has five or more spread codes corresponding to approach directions to the intersection, respectively.

8. The in-vehicle radio apparatus according to claim 2,

wherein regarding closely continuous intersections, the correspondence data has spread codes, corresponding to adjacent intersections, not to overlap with each other.

9. The in-vehicle radio apparatus according to claim 2,

wherein in a case where the correspondence data regarding an intersection which the vehicle is to enter can be obtained, the allocation unit allocates a spread code corresponding to an approach direction of the vehicle in the correspondence data as a spread code used for transmission by the transmission unit, and in a case where the correspondence data regarding the intersection which the vehicle is to enter cannot be obtained, the allocation unit allocates a spread code previously set corresponding to an approach direction of the vehicle as a spread code used for transmission by the transmission unit.

10. The in-vehicle radio apparatus according to claim 2,

wherein the correspondence data is included in map data.

11. The in-vehicle radio apparatus according to claim 2,

wherein in the correspondence data, multiple spread codes correspond to a particular approach direction to an intersection, and

wherein based on detection of existence of, between the intersection and the vehicle, a preceding vehicle that performs transmission of a radio signal with the spread code corresponding to the approach direction of the vehicle to the intersection, the code allocation unit allocates, among spread codes in the correspondence data corresponding to the approach direction of the vehicle to the intersection, a spread code different from the spread code used for transmission in the preceding vehicle, as a code used for transmission by the transmission unit.

12. The in-vehicle radio apparatus according to claim 1,

wherein the allocation unit specifies the spread code corresponding to the approach direction of the vehicle to the intersection based on a traveling direction of the vehicle and correspondence data between an approach direction to an intersection and the spread code by geographical division.

13. The in-vehicle radio apparatus according to claim 1, further comprising:

a different-timing transmission control unit for, based on detection of existence of, between the intersection and the vehicle, a preceding vehicle that performs transmission of a radio signal with the spread code corresponding to the approach direction of the vehicle to the intersection, performing the transmission by the transmission unit with the spread code allocated by the allocation unit at a timing different from a timing of transmission in the preceding vehicle.

14. The in-vehicle radio apparatus according to claim 1, further comprising:

a preceding vehicle detection unit for detecting existence of, between the intersection and the vehicle, a preceding vehicle that performs transmission of a radio signal with the spread code corresponding to the approach the direction of the vehicle to the intersection, and based on detection, prohibiting transmission by the transmission unit with the spread code allocated by the allocation unit.

15. The in-vehicle radio apparatus according to claim 14, further comprising:

a second approach determination unit for determining that the vehicle has entered a second distance shorter than the first distance from the intersection; and

a null data transmission control unit for, based on determination by the second approach determination unit, causing the transmission unit to transmit null data with the spread code allocated by the allocation unit, regardless of prohibition of transmission by the preceding vehicle detection unit.

16. The in-vehicle radio apparatus according to claim 15, wherein the null data transmission control unit causes the transmission unit to transmit the null data with transmission power lower than that when no preceding vehicle exists.

17. The in-vehicle radio apparatus according to claim 1, further comprising:

a first transmission power control unit for controlling transmission power of the transmission unit so that the transmission power is reduced as the distance between the vehicle and the intersection becomes shorter.

18. The in-vehicle radio apparatus according to claim 1, furthers comprising:

a second approach determination unit for determining that the vehicle has entered a second distance shorter than the first distance from the intersection; and

a first transmission power control unit for reducing transmission power of the transmission unit based on determination by the second approach determination unit.

19. The in-vehicle radio apparatus according to claim 1, wherein the signal transmitted by the transmission unit includes position data of the vehicle specified by a navigation apparatus by using map matching.

20. The in-vehicle radio apparatus according to claim 1,

wherein the first approach determination unit determines that the vehicle has entered the first distance from an intersection without a traffic light.

21. The in-vehicle radio apparatus according to claim 1,

wherein the first approach determination unit determines that the vehicle has entered the first distance from an intersection around which a building exists.

22. The in-vehicle radio apparatus according to claim 1, furthers comprising:

a reception unit for trying reception of a radio signal with a spread code corresponding to an approach direction different from the approach direction of the vehicle to the intersection, based on determination by the first approach determination unit.

23. The in-vehicle radio apparatus according to claim 22, further comprising:

a second transmission power control unit for controlling transmission power of the transmission unit based on a distance between a position of a vehicle as a transmission originator included as data in the signal received by the reception unit with the spread code corresponding to the approach direction different from the approach direction of the vehicle to the intersection and a position of the vehicle.

24. The in-vehicle radio apparatus according to claim 22, further comprising:

a notification unit for, in a case where the radio signal has been received with the spread code by trial of the reception by the reception unit, determining whether or not there is a probability of collision for the vehicle at the intersection based on the received signal, and if there is a probability of collision, notifying of the probability.

25. An in-vehicle radio apparatus comprising:

a transmission unit for transmitting a radio signal by using a spread spectrum method; and

an allocation unit for allocating a spread code corresponding to a traveling direction of a vehicle to an intersection as a spread code used for transmission by the transmission unit.

26. The in-vehicle radio apparatus according to claim 25, further comprising:

a unit for determining whether or not a current position of the vehicle is a position included in map data; and

a unit for, if the current position is not included in the map data, causing the transmission unit to always perform transmission by using the spread code allocated by the allocation unit.

27. An in-vehicle radio apparatus comprising:

a transmission unit for transmitting a radio signal;

a first approach determination unit for determining that a vehicle has entered a first distance from an intersection; and

an allocation unit for allocating a communication channel corresponding to an approach direction of the vehicle to the intersection as a communication channel used for transmission by the transmission unit based on determination by the first approach determination unit,

wherein the allocation unit specifies the communication channel corresponding to the approach direction of the vehicle to the intersection based on a traveling direction of the vehicle and correspondence data between the approach direction to a particular intersection and the communication channel.

28. The in-vehicle radio apparatus according to claim 27,

wherein in the correspondence data, regarding continuous multiple intersections, the same communication channel corresponds to a direction continuously passing the multiple intersections along a road.

29. The in-vehicle radio apparatus according to claim 27,

wherein in a case where the correspondence data regarding an intersection which the vehicle is to enter can be obtained, the allocation unit allocates a communication channel corresponding to an approach direction of the vehicle in the correspondence data as a communication channel used for transmission by the transmission unit, and in a case where the correspondence data regarding the intersection which the vehicle is to enter cannot be obtained, the allocation unit allocates a communication channel previously set corresponding to an approach direction of the vehicle as a communication channel used for transmission by the transmission unit.

30. An in-vehicle radio apparatus comprising:

a transmission unit for transmitting a radio signal;

a first approach determination unit for determining that a vehicle has entered a first distance from an intersection; and

an allocation unit for allocating a communication channel corresponding to an approach direction of the vehicle to the intersection as a communication channel used for transmission by the transmission unit based on determination by the first approach determination unit,

wherein the allocation unit specifies the communication channel corresponding to the approach direction of the vehicle to the intersection based on a traveling direction of the vehicle and correspondence data between an approach direction to an intersection and the communication channel by geographical division.

31. An in-vehicle radio apparatus comprising:

a transmission unit for transmitting a radio signal;

a first approach determination unit for determining that a vehicle has entered a first distance from an intersection;

an allocation unit for allocating a communication channel corresponding to an approach direction of the vehicle to the intersection as a communication channel used for transmission by the transmission unit based on determination by the first approach determination unit; and

a different-timing transmission control unit for, based on detection of existence of, between the intersection and the vehicle, a preceding vehicle that performs transmission of a radio signal in the communication channel corresponding to the approach direction of the vehicle to the intersection, performing the transmission by the transmission unit with the communication channel allocated by the allocation unit at a timing different from a timing of transmission in the preceding vehicle.

32. An in-vehicle radio apparatus comprising:

a transmission unit for transmitting a radio signal;

a first approach determination unit for determining that a vehicle has entered a first distance from an intersection;

an allocation unit for allocating a communication channel corresponding to an approach direction of the vehicle to the intersection as a communication channel used for transmission by the transmission unit based on determination by the first approach determination unit; and

a first transmission power control unit for controlling transmission power of the transmission unit so that the transmission power is reduced as the distance between the vehicle and the intersection becomes shorter.

33. An in-vehicle radio apparatus comprising:

a transmission unit for transmitting a radio signal;

a first approach determination unit for determining that a vehicle has entered a first distance from an intersection;

an allocation unit for allocating a communication channel corresponding to an approach direction of the vehicle to the intersection as a communication channel used for transmission by the transmission unit based on determination by the first approach determination unit; and

a preceding vehicle detection unit for detecting existence of, between the intersection and the vehicle, a preceding vehicle that performs transmission of a radio signal in the communication channel corresponding to the approach direction of the vehicle to the intersection, and based on the detection, prohibiting the transmission by the transmission unit in the communication channel allocated by the allocation unit.

34. The in-vehicle radio apparatus according to claim 33, further comprising:

a second approach determination unit for determining that the vehicle has entered a second distance shorter than the first distance from the intersection; and

a null data transmission control unit for, based on determination by the second approach determination unit, causing the transmission unit to transmit null data in the communication channel allocated by the allocation unit, regardless of prohibition of transmission by the preceding vehicle detection unit.

35. An in-vehicle radio apparatus comprising:

a transmission unit for transmitting a radio signal;

a first approach determination unit for determining that a vehicle has entered a first distance from an intersection;

an allocation unit for allocating a communication channel corresponding to an approach direction of the vehicle to the intersection as a communication channel used for transmission by the transmission unit based on determination by the first approach determination unit;

a second approach determination unit for determining that the vehicle has entered a second distance shorter than the first distance from the intersection; and

a first transmission power control unit for reducing transmission power of the transmission unit based on determination by the second approach determination unit.

36. An in-vehicle radio apparatus comprising:

a transmission unit for transmitting a radio signal;

a first approach determination unit for determining that a vehicle has entered a first distance from an intersection; and

an allocation unit for allocating a communication channel corresponding to an approach direction of the vehicle to the intersection as a communication channel used for transmission by the transmission unit based on determination by the first approach determination unit,

wherein the signal transmitted by the transmission unit includes position data of the vehicle specified by a navigation apparatus by using map matching.

37. An in-vehicle radio apparatus comprising:

a transmission unit for transmitting a radio signal;

a first approach determination unit for determining that a vehicle has entered a first distance from an intersection without a traffic light; and

an allocation unit for allocating a communication channel corresponding to an approach direction of the vehicle to the intersection as a communication channel used for transmission by the transmission unit based on determination by the first approach determination unit.

38. An in-vehicle radio apparatus comprising:

a transmission unit for transmitting a radio signal;

a first approach determination unit for determining that a vehicle has entered a first distance from an intersection around which a building exists; and

an allocation unit for allocating a communication channel corresponding to an approach direction of the vehicle to the intersection as a communication channel used for transmission by the transmission unit based on determination by the first approach determination unit.

39. An in-vehicle radio apparatus comprising:

a transmission unit for transmitting a radio signal;

a first approach determination unit for determining that a vehicle has entered a first distance from an intersection; and

an allocation unit for allocating a communication channel corresponding to an approach direction of the vehicle to the intersection as a communication channel used for transmission by the transmission unit based on determination by the first approach determination unit,

wherein regarding a five-forked or more-forked intersection, the communication channel includes five or more communication channels corresponding to approach directions to the intersection, respectively.

40. An in-vehicle radio apparatus comprising:

a transmission unit for transmitting a radio signal;

a first approach determination unit for determining that a vehicle has entered a first distance from an intersection; and

an allocation unit for allocating a communication channel corresponding to an approach direction of the vehicle to the intersection as a communication channel used for transmission by the transmission unit based on determination by the first approach determination unit,

wherein regarding closely continuous intersections, the communication channels that correspond to adjacent intersections do not overlap with each other.

41. An in-vehicle radio apparatus comprising:

a transmission unit for transmitting a radio signal;

a first approach determination unit for determining that a vehicle has entered a first distance from an intersection;

an allocation unit for allocating a communication channel corresponding to an approach direction of the vehicle to the intersection as a communication channel used for transmission by the transmission unit based on determination by the first approach determination unit; and

a reception unit for trying reception of a radio signal in a communication channel corresponding to an approach direction different from the approach direction of the vehicle to the intersection, based on determination by the first approach determination unit by using reception unit for transmitting a radio signal.

42. The in-vehicle radio apparatus according to claim 41, further comprising:

a notification unit for, in a case where the radio signal has been received in the communication channel by the trial of reception by the reception unit, determining whether or not there is a probability of collision for the vehicle at the intersection based on the received signal, and if there is a probability of collision, notifying of the probability.