JP4536606B2 - Wireless communication method, control station, and mobile station - Google Patents

Description

  The present invention relates to a wireless communication method that can be employed in a mobile communication system, and more particularly to a wireless communication method when a control station distributes information for each lane.

  In recent years, against the background of the development of wireless communication technology, network technology, and information technology, it has been desired that road traffic systems be advanced and computerized. In addition, information devices are being installed in vehicles such as car navigation. These information devices are expected to greatly improve convenience through provision of real-time information as well as information stored in advance such as map information. At present, as real-time information provision, for example, local traffic jam information is distributed by optical beacon, radio beacon, and FM broadcast multiplexing using VICS (Vehicle Information and Communication System).

  On the other hand, technological development is underway to provide more detailed information with the aim of reducing traffic accidents. For example, since many traffic accidents occur at intersections, a system that supports information on surrounding vehicles / pedestrians for each intersection and assists the driver in driving has been studied. In this system, in order to realize effective driving support, for example, it is desirable to distribute different information for each direction and lane (right turn, left turn, straight line) entering the intersection.

  For example, as a method of distributing different information for each lane, a method of irradiating different spot beams for each lane has been studied. In this system, each vehicle can obtain appropriate information simply by receiving radio waves.

  Further, as a conventional wireless communication system, for example, a system for collating and extracting corresponding data according to the traveling direction of each car on a wide area highway or the like is described in “Local Information Broadcasting System and its Broadcasting equipment and receiving terminal apparatus ". In the following Patent Document 1, the information to be transmitted includes information such as position information, traveling direction, and expiration date, and the receiver is configured to extract information that meets the conditions after accumulating the information.

JP 2003-284110 A

  However, in the method of distributing different information for each lane, there is a problem that many (usually several tens) antennas are required on the road unit in order to form an accurate beam for each lane. . In addition, when the propagation environment changes greatly due to the passage of a large vehicle or the like, there is a problem that it becomes difficult to realize stable communication such as the shape of the beam changes greatly and interference occurs between lanes.

  Further, in the above-mentioned Patent Document 1, all the information is once accumulated and the extraction process is performed after checking the conditions. Therefore, there is a problem that a processing delay occurs and a large storage device is required.

  The present invention has been made in view of the above, and an object of the present invention is to obtain a wireless communication method capable of realizing stable communication without using many antennas and a large storage device.

  In order to solve the above-described problems and achieve the object, a wireless communication method according to the present invention is provided in a wireless communication system in which synchronization is established between a control station and a mobile station by a beacon transmitted by a control station. A wireless communication method when a station distributes information for each lane, for example, a scheduling step in which the control station executes a scheduling process based on an information amount of transmission information for each lane (information for each lane) And a control data generation step in which the control station generates control data indicating a transmission frame structure (frame structure) based on the scheduling result, and the control station is based on the control data and the scheduling result. Transmitting a transmission frame including information for each lane that has undergone predetermined multiplexing processing, and the mobile station A position determining step for determining a lane position of the local station based on a measurement result of the local station position; and the multiplexed information for each lane based on the control data and the lane position of the local station. And an information receiving step of extracting information for the vehicle from the vehicle.

  According to the present invention, there is an effect that information for the own vehicle can be obtained by stable communication without using many antennas and a large storage device. In addition, since it is not necessary to extract extra information, the power consumption can be reduced and the apparatus scale can be reduced.

  Embodiments of a wireless communication method according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

Embodiment 1 FIG.
FIG. 1 is a diagram showing a system configuration example for realizing a wireless communication method according to the present invention, in which 1 to 12 represent lanes and 21 to 24 represent antennas on the road. In the example of FIG. 1, the intersection has a total of 12 lanes in four directions, and information is transmitted from four antennas. In such a system, communication that simultaneously transmits information from a plurality of antennas and does not cause interference is realized by, for example, an OFDM (Orthogonal Frequency Division Multiplexing) scheme. In this system, information for all 12 lanes is multiplexed and transmitted from each antenna, and each vehicle identifies the lane number of the own vehicle and extracts only data for the own vehicle. In FIG. 1, the circle on the road indicates the communication range of each antenna.

  FIG. 2 is a diagram illustrating an operation example of the first embodiment. B represents a beacon that is periodically transmitted, MAP represents control information indicating a frame structure, and Rx represents transmission information for lane x. . In this embodiment, transmission information for each lane is time-multiplexed, and the transmission timing of each information is written in the MAP. Each in-vehicle device analyzes the reception timing of information corresponding to the lane of the own vehicle from the MAP, and extracts only the corresponding information. Note that synchronization is established between the roadside device and the vehicle-mounted device by a beacon periodically transmitted by the roadside device.

  FIG. 3 is a diagram showing a configuration of a road machine (corresponding to a control station) according to the present invention. The road unit includes an antenna 31, an IF / RF unit 32 that performs processing for converting a high-frequency signal into a baseband signal, and processing for converting a baseband signal into a high-frequency signal, and transmission information for each lane ( Modulation unit 33 that modulates information for each lane), scheduling unit 34 that determines transmission timing using an information amount signal of the information for each lane, and generation of control data (control information) corresponding to the determined transmission timing And a timing control unit 36 that outputs information for each lane based on the transmission timing.

  FIG. 4 is a diagram showing a configuration of an in-vehicle device (corresponding to a mobile station) according to the present invention. This in-vehicle device demodulates the received signal, extracts control data and information for each lane, a lane position measurement unit 42 that measures the lane position of the host vehicle, and controls based on the measured lane position. A control data analysis unit 43 that analyzes data, and a timing control unit 44 that outputs transmission information for the own vehicle (information for the own vehicle) based on a reception timing that is an analysis result of the control data. In addition, about the structure similar to the said FIG. 3, the same code | symbol is attached | subjected and the description is abbreviate | omitted.

  Here, the operation of the first embodiment will be described with reference to the drawings. Information for each lane and an information amount signal for the information for each lane are input to the roadside machine. The scheduling unit 34 allocates information for each lane in the frame based on the information amount signal of the information for each lane. Specifically, the transmission timing of the control data and information for each lane is determined.

  The control data generation unit 35 generates control data based on the transmission timing of the information for each lane, and allocates the control data generated based on the transmission timing of the control data in the frame. The control data generated here includes the transmission time of information for each lane (generally, a relative position based on a beacon). Then, the generated control data is transmitted as a MAP shown in FIG. 2 after being modulated.

  The timing control unit 36 outputs the information for each lane to the modulation unit 33 based on the transmission timing of the information for each lane. The information for each lane sent to the modulation unit 33 is modulated, up-converted, and transmitted from the antenna 31.

  On the other hand, in the in-vehicle device, a beacon periodically transmitted from the road device is received, and time synchronization is established with respect to the road device. Further, as shown in FIG. 2, a MAP is arranged immediately after the beacon, and the demodulator 41 demodulates the received signal to obtain a demodulated signal of control data and information for each lane.

  In addition, the vehicle is equipped with a device capable of specifying the position and moving direction of the vehicle, such as a GPS receiver, a gyro, and an electronic tag reader embedded in the road surface. Therefore, the lane position measurement unit 42 uses the measurement results obtained by these devices to determine the lane position of the own vehicle at the intersection (corresponding to lanes 1 to 12 in FIG. 1).

  The control data analysis unit 43 calculates the reception timing of the information for the own vehicle based on the analysis result of the demodulated control data and the lane position determined as described above. Then, the timing control unit 44 extracts only the information for the own vehicle from the information for each lane after demodulation based on the reception timing calculated above, and outputs it.

  As described above, in the present embodiment, in a system that distributes different information for each lane, the road machine is in a predetermined position (beacon reference) in the frame in a state where synchronization between the road machine and the vehicle-mounted machine is established. The control data including the transmission time of the information for each lane is transmitted, and then the information for each lane is multiplexed and transmitted. On the other hand, the in-vehicle device measures the position of the traveling lane of the own vehicle (lane position) Based on the lane position of the vehicle and the control data, the reception timing of the information for the vehicle is obtained, and only the information for the vehicle is extracted from the multiplexed information for each lane based on the reception timing. . Thereby, the information for own vehicles can be obtained by stable communication, without using many antennas and a large storage device. Further, since it is not necessary to extract extra information, it is possible to reduce power consumption and apparatus size.

Embodiment 2. FIG.
In the second embodiment, a case will be described in which information for each lane is frequency-multiplexed and transmitted. In addition, about the structure of a roadside machine and vehicle equipment, it is the same as that of Embodiment 1 mentioned above. In the present embodiment, processing different from that of the first embodiment will be described.

  Here, the operation of the second embodiment will be described. FIG. 5 is a diagram illustrating an operation example of the second embodiment. In FIG. 5, the MAP after the beacon includes a frequency at which information for each lane is transmitted. The in-vehicle device receives and analyzes the MAP, and obtains a frequency at which the information for the vehicle is transmitted. And the reduction of an apparatus scale is achieved by receiving only the frequency used as object.

  Further, when OFDM is used as a communication method, frequency information is expressed by a subcarrier number. That is, the MAP is notified of the subcarrier number in which the information for each lane is arranged, and only the corresponding subcarrier is selectively received.

  By the processing of the present embodiment, even if the information for each lane is frequency-multiplexed, the same effect as that of the first embodiment can be obtained.

Embodiment 3 FIG.
In this embodiment, a case will be described in which information for each lane is code-multiplexed and transmitted. In addition, about the structure of a roadside machine and vehicle equipment, it is the same as that of Embodiment 1 mentioned above. In the present embodiment, processing different from that in the first or second embodiment will be described.

  Here, the operation of the third embodiment will be described. FIG. 6 is a diagram illustrating an operation example of the third embodiment. In FIG. 6, a specific spreading code is assigned to the MAP, and information relating to the spreading code used for transmission of information for each lane is transmitted as control information. The in-vehicle device determines the spreading code used for the information for the own vehicle from the MAP, and selectively receives only the information for the own vehicle. The excessive amount of information is dealt with by increasing or decreasing the number of assigned codes.

  Also, in the method of code-multiplexing information for each lane, the in-vehicle device can move to the next frame by shifting the control information arranged in the MAP and the information for each lane by one frame (the control information is one frame earlier). It is possible to know the spreading code of information arriving at. Thereby, selective reception is possible without arranging a storage device.

  Even if the information for each lane is code-multiplexed by the processing of the present embodiment, the same effects as those of the first and second embodiments described above can be obtained.

  As described above, the wireless communication method according to the present invention is useful as a communication method in a mobile communication system, and is particularly suitable as a wireless communication method when a control station distributes information for each lane.

It is a figure which shows the system configuration example for implement | achieving the radio | wireless communication method concerning this invention. 6 is a diagram illustrating an operation example of Embodiment 1. FIG. It is a figure which shows the structure of the road machine concerning this invention. It is a figure which shows the structure of the vehicle equipment concerning this invention. FIG. 10 is a diagram illustrating an operation example of the second embodiment. FIG. 10 is a diagram illustrating an operation example of the third embodiment.

Explanation of symbols

1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 Lane 21, 22, 23, 24, 31 Antenna 32 IF / RF unit 33 Modulating unit 34 Scheduling unit 35 Control data generating unit 36, 44 Timing control unit 41 Demodulation unit 42 Lane position measurement unit 43 Control data analysis unit

Claims (7)

In a wireless communication system in which synchronization is established between a control station and a mobile station by a beacon transmitted by the control station, a wireless communication method when the control station distributes information for each lane,
A scheduling step in which the control station performs a scheduling process based on an information amount of transmission information for each lane (information for each lane);
A control data generation step in which the control station generates control data indicating a structure of a transmission frame (frame structure) based on the scheduling result;
A transmission step in which the control station transmits a transmission frame including the control data and information for each lane that has undergone a predetermined multiplexing process based on the scheduling result;
The mobile station determines a lane position of the mobile station based on a measurement result of the mobile station position;
An information receiving step in which the mobile station extracts information for own vehicle from the multiplexed information for each lane based on the control data and the lane position of the own station;
A wireless communication method comprising: When adopting the time multiplexing method as the communication method,
In the control data generation step, control data including a transmission time of information for each lane is generated,
In the transmission step, time multiplexing is applied as the predetermined multiplexing process,
2. The wireless communication method according to claim 1, wherein in the information receiving step, information for the own vehicle is extracted from the time-multiplexed information for each lane. When adopting frequency multiplexing as the communication method,
In the control data generation step, control data including a frequency at which information for each lane is transmitted is generated,
In the transmission step, frequency multiplexing is applied as the predetermined multiplexing process,
2. The wireless communication method according to claim 1, wherein in the information receiving step, information for one's own vehicle is extracted from the information for each lane that has been frequency-multiplexed. 3. When adopting the Orthogonal Frequency Division Multiplexing (OFDM) method as the communication method,
In the control data generation step, control data including subcarrier positions where information for each lane is transmitted is generated,
In the transmission step, orthogonal frequency multiplexing is applied as the predetermined multiplexing process,
2. The wireless communication method according to claim 1, wherein in the information reception step, information for the own vehicle is extracted from the information for each lane that is frequency-multiplexed with the orthogonal wave. When a code multiplexing method is adopted as a communication method,
In the control data generation step, control data including a spread code used for information for each lane is generated,
In the transmission step, code multiplexing is applied as the predetermined multiplexing process,
2. The wireless communication method according to claim 1, wherein in the information receiving step, information for the own vehicle is extracted from the code-multiplexed information for each lane using the spreading code. A control station that configures a wireless communication system together with a mobile station that establishes synchronization by a beacon transmitted by the local station, and distributes information for each lane in the system,
Scheduling means for executing scheduling processing based on the amount of transmission information for each lane (information for each lane);
Control data generating means for generating control data indicating the structure of a transmission frame based on the scheduling result;
Transmitting means for transmitting a transmission frame including the control data and information for each lane that has been subjected to predetermined multiplexing processing based on the scheduling result;
A control station comprising: A structure of a transmission frame that configures a wireless communication system together with a control station that distributes transmission information (information for each lane) for each lane, establishes synchronization by a beacon transmitted by the control station, and further transmits the control station A mobile station that receives control data indicating lane information and information for each lane that has undergone a predetermined multiplexing process,
Position determining means for determining the lane position of the own station based on the measurement result of the own station position;
Receiving means for extracting information for own vehicle from the multiplexed information for each lane based on the control data and the lane position of the own station;
A mobile station comprising:

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