JP2010035182A - Communication apparatus, method of communication, and recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To configure an environment for performing stable wireless communication inexpensively. <P>SOLUTION: A vehicle 2 performs relayed communication, which relays wireless communication between a base station 1, which is arranged in such a way that a wireless communication area where wireless communication is possible becomes discrete, and other vehicle 2, to control whether to perform relayed communication based on predetermined control information. The base station 1 recognizes the state of the other vehicle 2, which is a mobile station, generates control information for controlling whether to make a predetermined mobile station to perform relayed communication, which relays wireless communication with the other mobile station, and transmits control information. The vehicle 2 performs wireless communication with the base station 1 utilizing direct communication by a first communication apparatus that performs direct communication which is direct communication with the base station 1, which is arranged in such a way that a wireless communication area where wireless communication is possible becomes discrete, and relayed communication by a second communication apparatus that performs relayed communication which relays wireless communication with the base station 1. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a communication device, a communication method, and a recording medium, and more particularly, to a communication device, a communication method, and a recording medium that enable an environment for performing wireless communication to be established at low cost.

  For example, in order to install a base station on a road and perform stable wireless communication between the base station and an automobile or other vehicle as a mobile station, in general, a plurality of base stations It is necessary to install the stations so that wireless areas where wireless communication is possible overlap.

  Therefore, for example, in order to perform stable wireless communication on a certain high-speed road or toll road as a whole, it is necessary to install a large number of base stations. It will be.

  Therefore, for example, there is a method of reducing the number of base stations to be installed by expanding the radio area of the base station. In this case, however, the number of radio channels that can be allocated per unit area of the radio area is reduced. Will do.

  On the other hand, when the radio area of the base station is reduced, the number of radio channels that can be allocated per unit area of the radio area can be increased. In this case, the base station to be installed is described above. The number of will increase. Further, in this case, the mobile station frequently moves from the radio area of a certain base station to the radio area of another base station during communication, and stable radio communication becomes difficult. That is, for example, a momentary disconnection due to wireless channel switching control accompanying the movement of the wireless area is likely to occur, and a forced disconnection due to the absence of an assignable wireless channel in the movement destination wireless area is also likely to occur.

  The present invention has been made in view of such a situation, and makes it possible to construct an environment for performing stable wireless communication at a low cost.

  The communication device according to the first aspect of the present invention is a relay that relays wireless communication between a base station arranged so that wireless areas capable of wireless communication are discrete and another communication device. A relay communication unit that performs communication and a communication control unit that controls whether to perform relay communication based on predetermined control information.

  The communication method according to the first aspect of the present invention is communication for relaying wireless communication between a base station arranged so that wireless areas capable of wireless communication are discrete and a movable communication device. A relay communication step for performing relay communication and a communication control step for controlling whether to perform relay communication based on predetermined control information are provided.

  The recording medium according to the first aspect of the present invention is a communication that relays wireless communication between a base station arranged so that wireless areas capable of wireless communication are discrete and a movable communication device. A program comprising a relay communication step for performing relay communication and a communication control step for controlling whether to perform relay communication based on predetermined control information is recorded.

  The communication device according to the second aspect of the present invention relays wireless communication with another mobile station to a predetermined mobile station based on the recognition means for recognizing the state of the mobile station and the state of the mobile station. It is characterized by comprising generating means for generating control information for controlling whether to perform relay communication, which is communication, and transmitting means for transmitting control information.

  The communication method according to the second aspect of the present invention includes a recognition step for recognizing a state of a mobile station, and communication for allowing a predetermined mobile station to relay wireless communication with another mobile station based on mobile station information. A generation step for generating control information for controlling whether or not to perform relay communication, and a transmission step for transmitting control information.

  The recording medium according to the second aspect of the present invention relays wireless communication with another mobile station to a predetermined mobile station based on the recognition step for recognizing mobile station information regarding the mobile station and the mobile station information. A program comprising a generation step for generating control information for controlling whether to perform relay communication, which is communication to be performed, and a transmission step for transmitting control information is recorded.

  The communication apparatus according to the third aspect of the present invention is a direct communication by a first communication apparatus that performs direct communication that is direct communication with a base station that is arranged so that wireless areas capable of wireless communication are discrete. And communication means for performing wireless communication with the base station using relay communication by the second communication device that performs relay communication, which is communication for relaying wireless communication with the base station. To do.

  The communication method according to the third aspect of the present invention is a direct communication by a first communication device that performs direct communication that is direct communication with a base station that is arranged so that wireless areas capable of wireless communication are discrete. And a communication step of performing wireless communication with the base station using relay communication by the second communication device that performs relay communication, which is communication that relays wireless communication with the base station. To do.

  The recording medium according to the third aspect of the present invention is a direct communication by a first communication device that performs direct communication that is direct communication with a base station that is arranged so that wireless areas capable of wireless communication are discrete. And a program including a communication step for performing wireless communication with the base station using the relay communication by the second communication device that performs relay communication, which is communication for relaying wireless communication with the base station, is recorded. It is characterized by.

  In the communication device, the communication method, and the recording medium according to the first aspect of the present invention, between the base station arranged so that the wireless areas capable of wireless communication are discrete and the movable communication device Whether to perform relay communication, which is communication for relaying wireless communication, is controlled based on predetermined control information.

  In the communication apparatus, communication method, and recording medium according to the second aspect of the present invention, mobile station information related to a mobile station is recognized, and based on the mobile station information, a predetermined mobile station can communicate with other mobile stations. Control information for controlling whether to perform relay communication, which is communication for relaying wireless communication between the two, is generated and transmitted.

  In the communication device, the communication method, and the recording medium according to the third aspect of the present invention, direct communication that is direct communication with a base station arranged so that wireless areas capable of wireless communication are discrete is performed. Wireless communication with the base station is performed using direct communication by the first communication device and relay communication by the second communication device that performs relay communication, which is communication that relays wireless communication with the base station. Is called.

  According to the communication device, the communication method, and the recording medium of the first to third aspects of the present invention, it is possible to perform stable communication while reducing the cost of installing a base station.

It is a figure which shows the structural example of one Embodiment of the communication system to which this invention is applied. It is a figure for demonstrating the communication method between the base station 1 and the vehicle 2 of FIG. It is a figure explaining a control channel and a traffic channel. 2 is a block diagram illustrating a configuration example of a base station device of a base station 1. FIG. It is a flowchart explaining the process of a base station apparatus. 2 is a block diagram illustrating a configuration example of a mobile station device mounted on a vehicle 2. FIG. It is a flowchart explaining the communication control process by a mobile station apparatus. It is a flowchart explaining the data reception process and data transmission process by a mobile station apparatus. It is a flowchart explaining the data reproduction process by a mobile station apparatus. 3 is a block diagram illustrating a configuration example of a central control device of a central control station 3. FIG. It is a figure which shows the structural example of other embodiment of the communication system to which this invention is applied. It is a block diagram which shows the structural example of one Embodiment of the computer to which this invention is applied.

    FIG. 1 shows a configuration example of an embodiment of a communication system to which the present invention is applied.

In FIG. 1, vehicles (automobiles) 2 ₁ , 2 ₂ , 2 ₃ , mobile stations as mobile stations are installed on the roads such as highways and toll roads where base stations 1 ₁ , 1 ₂ ,. ... is running from right to left in the figure.

  Here, in order to simplify the description, it is assumed that the road is one-dimensionally expressed (linear one). However, the present invention can also be applied to roads that are not represented one-dimensionally.

The base stations 1 ₁ , 1 ₂ ,... Can perform wireless communication with a vehicle 2 _i as a mobile station within a predetermined range from each of the base stations 1 ₁ , 1 ₂ ,. Now, assuming that the range in which the base station 1 _j can perform wireless communication is a wireless area, in FIG. 1, the base stations 1 ₁ , 1 ₂ ,... Is installed on the road.

That is, in FIG. 1, the adjacent base stations 1 ₁ and 1 ₂ have wireless areas in the range indicated by hatching in the figure so that the respective wireless areas do not overlap and become discrete. is set up. Therefore, the vehicles 2 ₁ , 2 ₂ , 2 ₃ ,... As mobile stations communicate directly with the base station 1 _j having the radio area only when traveling in the radio area. When the vehicle is traveling outside the wireless area, wireless communication with the base station 1 _j is not possible.

In FIG 1, the vehicle 2 ₁ is traveling on a base station 1 _first wireless area, therefore, it is possible to directly wirelessly communicate with the base station 1 _1. Further, the vehicle 2 ₂ is traveling in the radio area of the base station 1 _2, therefore, it is possible to directly wirelessly communicate with the base station 1 _2. However, the vehicle 2 ₃ is traveling outside the wireless area, therefore, not directly able to wirelessly communicate with the base station 1 ₁ and 1 _2.

Hereinafter, the base stations 1 ₁ , 1 ₂ ,... Will be referred to as the base station 1 unless it is particularly necessary to distinguish them. Similarly, vehicles 2 ₁ , 2 ₂ , 2 ₃ ,... As mobile stations are also referred to as vehicles 2. Further, the direct wireless communication between the base station 1 and the vehicle 2 is hereinafter also referred to as road-to-vehicle communication as appropriate.

  The base station 1 appropriately transmits necessary information among the information obtained by performing communication with the vehicle 2 to the central control station 3, and receives information transmitted from the central control station 3, Based on the information and the information obtained from the vehicle 2, a predetermined process is performed.

  The central control station 3 controls and manages the base station 2 by communicating with the base station 1.

  Note that communication between the base station 1 and the centralized control station 3 may be performed either wirelessly or by wire.

As described above, the base stations 1 ₁ , 1 ₂ ,... Are arranged on the road so that their wireless areas are discrete, and therefore the number of base stations 1 to be installed is small. The cost of installing a base station can be reduced.

  Next, a communication method between the base station 1 and the vehicle 2 in the communication system of FIG. 1 will be described with reference to FIG.

  For example, as shown in FIG. 2A, which is similar to FIG. 1, when the number of vehicles 2 traveling on the road is small, the average vehicle speed of the vehicles 2 is high and the vehicle interval is wide. However, it is known for traffic engineering.

Thus, in FIG. 2 (A), the example, the vehicle 2 ₁ traveling a radio area of the base station 1 _1, after exiting from the wireless area, to the wireless area of the base station 1 ₂ which is the next wireless area, You can arrive (move) in a short time.

  Therefore, as shown in FIG. 2A, when the number of vehicles 2 traveling on the road is small, for example, when there is data to be uploaded from the vehicle 2, the vehicle 2 is traveling in the wireless area. If so, data is transmitted to the base station 1 by performing road-to-vehicle communication with the base station 1 having the wireless area. If the data upload is not completed within the time when the vehicle 2 is traveling in the wireless area of the base station 1, the vehicle 2 interrupts road-to-vehicle communication and sequentially accumulates data to be uploaded. (Remember. Then, when the vehicle 2 enters the wireless area again, it continues the upload. That is, the vehicle 2 transmits the data accumulated while the road-vehicle communication is interrupted to the base station 1 by performing the road-vehicle communication with the base station 1.

  As described above, the data from the vehicle 2 transmitted to the base station 1 is transmitted to the central control station 3, and the central control station 3 transmits the data to another base station or a predetermined network. .

  When the number of vehicles 2 traveling on the road is small, when downloading time-series data such as video data such as movies, audio data such as songs, and other data from the base station 1, the vehicle 2 If the vehicle is traveling in a wireless area, the data is downloaded and stored (stored) as much as possible by performing road-to-vehicle communication with the base station having the wireless area, and the downloaded data is reproduced. . When the base station 1 is requested to download data from the vehicle 2, the base station 1 obtains the data requested to be downloaded from the central control station 3 or the like as necessary.

  If downloading of data does not end within the time when the vehicle 2 is traveling in the wireless area of the base station 1, the vehicle 2 interrupts road-to-vehicle communication but continues to reproduce data. That is, here, for example, if the data to be downloaded is compressed, or if the transfer speed for downloading the data is sufficiently faster than the data reproduction speed, even when the vehicle 2 leaves a certain wireless area. In the vehicle 2, data downloaded in the wireless area and not yet reproduced is accumulated. Therefore, the vehicle 2 continues reproduction using the data.

  In this case, since the number of vehicles 2 traveling on the road is small, the travel time from when the vehicle 2 leaves a certain wireless area until it arrives at the next wireless area is short. While the recorded data is being reproduced, that is, while the accumulated data remains, the next radio area can be reached. As described above, when the vehicle 2 enters the next wireless area, the vehicle 2 continues the download. That is, the vehicle 2 continues the interrupted download by performing road-to-vehicle communication with the base station 1 having the entered wireless area.

  Therefore, it is possible to prevent the reproduction of data contents such as movies and songs from being interrupted in the middle of a certain wireless area without the end of data download. Is realized.

  Next, for example, as shown in FIG. 2B, when the number of vehicles 2 traveling on the road increases, a vehicle group is formed, resulting in traffic jams. That is, as the number of vehicles 2 increases, the average vehicle speed of the vehicles 2 decreases and the vehicle interval decreases. As a result, a group of vehicles is formed, causing traffic jams.

In FIG. 2 (B), the vehicle 2 ₂ in the wireless area of the base station 1 ₂ as the top with a vehicle 2 _4, 2 ₃ outside the wireless area, the vehicle group is formed. In addition, the vehicle 2 ₁ is about to leave the radio area of the base station 1 ₁ .

In this case, since the vehicle group formed by the vehicles 2 ₂ , 2 ₄ , 2 ₃ exists in the traveling direction of the vehicle 2 ₁ , the data accumulated after leaving the radio area of the base station 11 ₁ it is while remaining, to arrive at the radio area of the base station 1 ₂ which is the next wireless area becomes difficult, so that data reproduction, may be interrupted in the middle.

  Therefore, the vehicle 2 can perform relay communication that is communication for relaying wireless communication between the base station 1 and another vehicle. That is, when receiving a radio wave (or light, etc.) by wireless communication, the vehicle 2 performs relay communication that amplifies the radio wave and retransmits it as necessary.

Specifically, in FIG. 2 (B), the vehicle 2 ₂ in the wireless area of the base station 1 ₂ receives radio waves by road-to-vehicle communication with the base station 1 _2, performs relay communication. Telecommunications by the relay communication of the vehicle 2 ₂ is received by the vehicle 2 ₄ immediately thereafter, the vehicle 2 ₄ also performs relay communication. Telecommunications by the relay communication of the vehicle 2 ₄ is received by the vehicle 2 ₃ immediately thereafter, the vehicle 2 ₃ also performs relay communication. Therefore, if the vehicle 2 ₁ arrives near the vehicle 2 ₃ , the vehicle 2 ₁ can receive radio waves by relay communication by the vehicle 2 ₃ . That is, even if the vehicle 2 ₁ is not within the radio area of the base station 1 ₂ , the vehicle 2 ₁ uses the road-to-vehicle communication and relay communication by the vehicle 2 ₂ , and further uses the relay communication by the vehicles 2 ₃ and 2 _4. it can perform wireless communication with the station 1 _2.

  Accordingly, stable communication can be performed even when the number of vehicles 2 traveling on the road is large.

Incidentally, in FIG. 2 (B), the upload of data from the vehicle 2 ₁ that has arrived in the vicinity of the vehicle 2 _3, radio waves from the vehicle 2 ₁ is relayed by the vehicle 2 _3, 2 _4, 2 ₂ of the order At the same time, it is realized by performing road-to-vehicle communication between the vehicle 2 ₂ and the base station 1 ₂ .

  In addition, the reach of radio waves by relay communication can be a range that is somewhat wider than the interval formed between the vehicles when the number of vehicles increases to some extent, for example.

Furthermore, even when the number of vehicles 2 traveling on the road is larger than in the case of FIG. 2 (B), as described in FIG. 2 (B), using road-to-vehicle communication and relay communication, vehicle 2 not in the wireless area is, it is possible to communicate with the base station 1, for example, as shown in FIG. 2 (C), as the first vehicle 2 ₂ in the wireless area of the base station 1 ₂ When a vehicle group is formed together with the vehicles 2 ₄ , 2 ₃ , 2 ₅ , 2 ₁ , and the vehicle 2 _1, which is a vehicle behind the vehicle group, is in the radio area of the base station 1 ₁ immediately before the base station 1 _2. The downloading and uploading of data can be performed, for example, in the direction indicated by the dotted arrow in FIG. 2C (or the opposite direction).

The vehicle 2 _i is by receiving a radio wave from the base station 1 or another vehicle 2 _j, further retransmitted to relay communication to other vehicle 2 _k is the communication between the vehicle 2 _i and 2 _k Since it seems to be performed, it is also referred to as vehicle-to-vehicle communication as appropriate.

  Next, a radio channel used for radio communication between the base station 1 and the vehicle 2 will be described.

  In the present embodiment, the wireless communication between the base station 1 and the vehicle 2 is performed by, for example, a TDMA (Time Division Multiple Access) method. As a wireless channel, for example, as shown in FIG. A frequency band as such a control channel (FIG. 3A) and a frequency band as a traffic channel (FIG. 3B) are prepared.

  Each of the control channel and the traffic channel is composed of a TDMA frame having a predetermined time length, and each TDMA frame is time-divided into units called slots.

  The control channel is used for slot allocation to the vehicle 2, switching control of slots allocated to the vehicle, communication path control, transmission / reception timing control, transmission output control, and the like. Furthermore, the control channel is also used for transmission of control information, mobile station information, and the like, which will be described later.

  The control channel is constantly transmitted from the base station 1, and the vehicle 2 that has received the control channel always transmits the control channel by inter-vehicle communication. Therefore, if the vehicle 2 is within the radio area of the base station 1 or can receive radio waves from other vehicles by inter-vehicle communication, the vehicle 2 can always receive the control channel.

  The TDMA frame of the control channel is configured such that a common slot is arranged at the head thereof, and thereafter a predetermined number of individual slots are arranged. The common slot of the control channel (hereinafter referred to as “control common slot” as appropriate) is used for exchange of control information and the like with the vehicle 2 to which the individual slot of the control channel (hereinafter referred to as “control individual slot” as appropriate) is not assigned. The control individual slot is assigned to the vehicle 2, and after the control individual slot is assigned, exchange of control information and the like between the vehicle 2 and the base station 1 is performed using the control individual slot.

  The traffic channel is used for transmission of data from the vehicle 2 to the base station 1 (uploading and transmission (downloading) of data from the base station 1 to the vehicle 2. That is, the traffic channel is data (actual data) to be originally transmitted. ).

  The TDMA frame of the traffic channel is configured by arranging a predetermined number of individual slots, and this individual slot of the traffic channel (hereinafter referred to as a traffic individual slot as appropriate) is used when the vehicle 2 uploads or downloads data. And assigned to the vehicle 2. Then, data transmission / reception is performed between the base station 1 and the vehicle 2 using the traffic individual slots assigned to the vehicle 2.

  In addition, as a control channel, a different frequency band can also be used by road-to-vehicle communication and vehicle-to-vehicle communication, and the same frequency band can also be used. Furthermore, when the same frequency band is used as a control channel for road-to-vehicle communication and vehicle-to-vehicle communication, the slots to be used can be divided between road-to-vehicle communication and vehicle-to-vehicle communication.

  In FIG. 3, the control channel and the traffic channel are provided in different frequency bands, but the control channel and the traffic channel may be provided in the same frequency band.

  Next, FIG. 4 illustrates a configuration example of a base station apparatus that the base station 1 has.

  The antenna 11 transmits a signal from the transmission / reception unit 12 as a radio wave, receives a radio wave transmitted from the vehicle 2, and supplies the reception signal to the transmission / reception unit 12.

  The transmission / reception unit 12 performs processing necessary for demodulation and other reception on the received signal from the antenna 11, and information on the vehicle 2 as a mobile station among the signals obtained as a result (hereinafter referred to as mobile station as appropriate). (Referred to as information) is supplied to the measurement unit 13 and a request for downloading or uploading data is supplied to the request processing unit 16. Further, the transmission / reception unit 12 performs modulation and other processing necessary for transmission on the data from the request processing unit 16 and supplies the data to the antenna 11.

  Based on the mobile station information from the transmission / reception unit 12, the measurement unit 13 measures the vehicle speed and the vehicle interval of each vehicle, the number of vehicles between itself and the next or previous base station, and the like as necessary ( Calculated) and supplied to the calculation unit 14.

  Here, as the mobile station information, for example, identification information for identifying the vehicle 2 that has transmitted the mobile station information (for example, the number of the number plate), the electric field of the radio wave as the control channel received by the vehicle 2 Strength, identification information (for example, IP (Internet Protocol) address, etc.) of the communication partner with which the vehicle 2 is finally going to communicate, location information of the vehicle 2, amount of data to be uploaded from the vehicle 2, upload or download The degree of importance of data to be attempted (for example, data with high immediacy), emergency information indicating that an emergency has occurred (for example, an accident, etc.), and the like.

  The mobile station information is transmitted from the vehicle 2 to the base station 1 through a control channel (FIG. 3A). However, for example, when a control individual slot is not assigned to the vehicle 2, it is transmitted using the control common slot, and when a control individual slot is assigned to the vehicle 2, it is assigned. It is transmitted using a control individual slot.

The measurement unit 13 obtains the vehicle speed, the vehicle interval, the number of vehicles, and the like based on the mobile station information transmitted from each of the vehicles 2 ₁ , 2 ₂ ,.

  The vehicle speed of the vehicle 2 and the vehicle interval between the vehicle 2 and the preceding and following vehicles can be transmitted from the vehicle 2 as mobile station information instead of being obtained by the measurement unit 13. It is. Also, for example, when the control individual slot (FIG. 3A) is not assigned to the vehicle 2, the measurement unit 13 of the base station 1 obtains the vehicle speed and the vehicle interval, and When the control individual slot is allocated, it is possible to have the vehicle 2 transmit the vehicle speed and the vehicle interval as mobile station information.

The vehicle speed, the vehicle interval, the number of vehicles, and the like obtained by the measurement unit 13 are supplied to a calculation unit 14 and a communication I / F (Interface) 17. Furthermore, the output of the communication I / F 17 is also supplied to the calculation unit 14. That is, information such as the vehicle speed obtained from each base station 1 ₁ , 1 ₂ ... Is transmitted to the central control station 3 (FIG. 1). Transmits information from each base station to other base stations as necessary. The communication I / F 17 receives information on other base stations transmitted from the central control station 3 in this way and supplies the information to the calculation unit 14.

  The calculation unit 14 is a movement required for a certain vehicle to move from the current location to the wireless area based on the measurement unit 13 and, if necessary, information on other base stations supplied from the communication I / F 17. Time (predicted value thereof) and the like are calculated and supplied to the control information generating unit 15.

  In addition to the output of the calculation unit 14, information of other base stations is supplied to the control information generation unit 15 from the communication I / F 17. The control information generation unit 15 generates control information based on the output from the calculation unit 14 and information from the communication I / F 17 and supplies the control information to the transmission / reception unit 12 and the request processing unit 16.

  Here, as the control information, for example, the identification information of the vehicle 2 that should receive the control information, the travel time obtained by the calculation unit 14, a request for road-to-vehicle communication or vehicle-to-vehicle communication for the vehicle 2, a communication path, There are a transmission output power required for the vehicle 2, a slot ID (Identification) for identifying a control individual slot and a traffic individual slot assigned to the vehicle 2, and the like.

  The control information is transmitted from the base station 1 to the vehicle 2 using a common slot of the control channel. Therefore, the vehicle 2 basically only needs to constantly monitor only the common slot of the control channel. When the vehicle 2 recognizes the control individual slot assigned to itself by receiving the control information, the vehicle 2 establishes the control individual slot with the base station 1 while the control individual slot is assigned. Used to transmit and receive mobile station information and control information.

  Here, the base station 1 may use the assigned control individual slot when transmitting control information for assigning the control individual slot to the vehicle 2. However, in this case, the vehicle 2 cannot recognize the control individual slot assigned to the vehicle 2 until receiving the control information, and therefore monitors not only the control common slot but all slots of the control channel. Need to be.

  The request processing unit 16 receives a data download or upload request from the transmission / reception unit 12 and processes the request. That is, when the request processing unit 16 receives a data download request from the transmission / reception unit 12, the request processing unit 16 requests and acquires the data requested for download from the central control station 3 or the like via the communication I / F 17. The data is supplied to the transmission / reception unit 12. Further, when a request for uploading data is received from the transmission / reception unit 12, the request processing unit 16 receives data transmitted from the vehicle 2 supplied from the transmission / reception unit 12 and transmits the data to the communication I / F 17. Let

The request processing unit 16 recognizes the control individual slots and traffic individual slots assigned to the vehicles 2 ₁ , 2 ₂ ,... By referring to the control information output by the control information generation unit 15. Further, it recognizes the vehicle that has transmitted the data download or upload request and the traffic individual slot to be used for the download or upload. Then, the request processing unit 16 instructs the transmission / reception unit 12 which traffic individual slot should be used when the transmission / reception unit 12 transmits / receives data.

  The communication I / F 17 performs communication control with the central control station 3 and a predetermined network such as the Internet under the control of the request processing unit 16. Further, the communication I / F 17 transmits the vehicle speed and the like output from the measurement unit 13 to the central control station 3. Further, the communication I / F 17 supplies the vehicle speed and the like obtained from other base stations transmitted from the central control station 3 to the calculation unit 14 and the control information generation unit 15.

  Next, processing of the base station 1 (base station apparatus) in FIG. 4 will be described with reference to the flowchart in FIG. Here, the processing of the base station 1 will be described by paying attention to a certain vehicle 2, but the base station 1 performs the same processing for other vehicles.

  The antenna 11 receives radio waves from a vehicle in the radio area of the base station 1, and a reception signal obtained as a result is supplied to the transmission / reception unit 12.

  First, in step S1, the transmission / reception unit 12 determines whether or not it is the timing of the control common slot, and if it is determined that it is the timing, the process proceeds to step S2, and the vehicle 2 It is determined whether or not the mobile station information is arranged. If it is determined in step S2 that the mobile station information of the vehicle 2 is not arranged in the control common slot, the process returns to step S1 and the same processing is repeated thereafter.

  When it is determined in step S2 that the mobile station information of the vehicle 2 is arranged in the control common slot, the transmission / reception unit 12 supplies the mobile station information of the vehicle 2 to the measurement unit 13, Proceed to step S3. In step S3, the measurement unit 13 calculates the vehicle speed of the vehicle 2, the distance between the vehicles before and after the vehicle 2, the number of vehicles near the current location of the vehicle 2, and the like based on the mobile station information of the vehicle 2 from the transmission / reception unit 12. And supplied to the calculation unit 14. Note that the information obtained by the measurement unit 13 is also transmitted to the centralized control station 3 via the communication I / F 17.

  Thereafter, the process proceeds to step S4, where the calculation unit 14 determines the vehicle based on the output from the measurement unit 13 and further information from another base station from the central control station 3 supplied via the communication I / F 17. Processing such as calculation of travel time required for 2 to move to the next wireless area, determination of whether or not inter-vehicle communication is possible, and the like are performed, and the processing result is supplied to the control information generation unit 15. The control information generation unit 15 assigns a control individual slot to the vehicle 2 in step S5.

  In other words, in this case, the mobile station information from the vehicle 2 has been arranged and transmitted in the control common slot, and therefore the control individual slot has not yet been assigned to the vehicle 2. For this reason, the control information generation part 15 allocates the control common slot for transmitting / receiving mobile station information, control information, etc. between the vehicles 2 in step S5.

  And it progresses to step S6, and the control information generation part 15 considers the information from the other base station from the central control station 3 supplied via the output of the calculating part 14, and communication I / F17, Control information for the vehicle 2 is generated, and the control information including the slot ID of the control common slot assigned in step S5 is supplied to the transmission / reception unit 12. In step S7, the transmission / reception unit 12 arranges the control information from the control information system generation unit 15 in the control common slot, transmits it as a radio wave from the antenna 11, and returns to step S1.

  The vehicle 2 receives the control information transmitted in this manner, thereby recognizing the control individual slot assigned to itself, and thereafter, the assigned control individual slot (hereinafter referred to as the assignment slot as appropriate). ) Is used to exchange control information and mobile station information with the base station 1.

  The control individual slot assigned to the vehicle 2 is, for example, a state in which the vehicle 2 cannot communicate with the base station 1 (the vehicle 2 cannot perform road-to-vehicle communication with the base station 1, It is released when it becomes a state in which communication using inter-vehicle communication or inter-vehicle communication is not possible.

  On the other hand, if it is determined in step S1 that it is not the timing of the control common slot, that is, if it is the timing of one of the control individual slots, the process proceeds to step S8, where the transmitting / receiving unit 12 It is determined whether it is the timing of the slot (allocated slot).

  When it is determined in step S8 that the timing of the allocation slot is reached, the process proceeds to step S9, and the transmission / reception unit 12 determines whether the mobile station information of the vehicle 2 is arranged in the allocation slot. In step S9, when it is determined that the mobile station information of the vehicle 2 is arranged in the allocation slot, the process proceeds to steps S10 to S12 sequentially, and the same processing as in steps S4, S6, and S7 is performed. Thereby, control information is transmitted to the vehicle 2.

  That is, since the situation of the vehicle on the road including the vehicle 2 changes from moment to moment, the base station 1 updates the control information based on the situation that changes, and the control after the update. Information is transmitted to the vehicle 2.

  When the process of step S12 is performed, since the control individual slot is already assigned to the vehicle 2, the control information is arranged in the assigned control individual slot (assignment slot). Sent.

  In step S12, after the control information is transmitted to the vehicle 2, the process returns to step S1, and the same processing is repeated thereafter.

  On the other hand, if it is determined in step S9 that the mobile station information of the vehicle 2 is not arranged in the allocation slot, the process proceeds to step S13, and the transmission / reception unit 12 sends a message requesting data transfer to the allocation slot (hereinafter, referred to as “data transfer”) Data transfer request message) is arranged. If it is determined in step S13 that the data transfer request message is not arranged in the allocation slot, the process returns to step S1 and the same processing is repeated thereafter.

  If it is determined in step S13 that the data transfer request message is arranged in the allocation slot, the process proceeds to step S14, and the request processing unit 16 transmits traffic to the vehicle 2 for transferring data. A process for assigning individual slots (traffic individual slots) of the channel is performed.

  That is, the request processing unit 16 allocates a traffic individual slot to the vehicle 2, supplies the slot ID of the allocated traffic individual slot to the transmission / reception unit 12, and transmits the control information using the allocation slot.

  By receiving this control information, the vehicle 2 recognizes the traffic individual slot assigned to itself.

  In step S15, the request processing unit 16 performs processing for data transfer using the traffic individual slot assigned to the vehicle 2.

  In other words, when the data transfer request message from the vehicle 2 is a request for data download, the request processing unit 16 controls the communication I / F 17 to concentrate the data requested for download. Download from the control station 3 or the like. Further, the request processing unit 16 controls the transmission / reception unit 12 to transmit the data downloaded from the central control station 3 or the like using the traffic individual slot assigned to the vehicle 2.

  Then, the request processing unit 16 completes the transmission of the data requested to be downloaded from the vehicle 2 or when the vehicle 2 cannot receive the radio wave from the base station 1, And the traffic individual slot assigned to the vehicle 2 is released, and the process returns to step S1.

  When the data transfer request message from the vehicle 2 is a request for data upload, the request processing unit 16 sends the request from the vehicle 2 arranged and transmitted in the traffic individual slot assigned to the vehicle 2. The data is received by the transmission / reception unit 12. Further, the request processing unit 16 controls the communication I / F 17 to transmit the data received from the transmission / reception unit 12 to the central control station 3 or a predetermined network.

  Then, the request processing unit 16 completes reception of the data requested to be uploaded from the vehicle 2 or when the vehicle 2 cannot receive radio waves from the base station 1, And the traffic individual slot assigned to the vehicle 2 is released, and the process returns to step S1.

  Next, FIG. 6 shows a configuration example of a mobile station apparatus that the vehicle 2 as a mobile station has.

  The antenna 21 </ b> A is an antenna for transmitting and receiving radio waves for inter-vehicle communication with a vehicle in front of the vehicle 2, and has directivity in front of the vehicle 2, for example. The antenna 21 </ b> B is an antenna for transmitting and receiving radio waves for inter-vehicle communication with a vehicle behind the vehicle 2, and has directivity behind the vehicle 2, for example. As antennas 21A and 21B, antennas having no directivity can be used. However, when antennas having directivity are used, transmission power can be kept low, and the frequency band can be used effectively. It becomes possible to do. The same effect can be obtained by changing the plane of polarization of the radio wave used for each mobile station apparatus.

  The antenna 21 </ b> C is an antenna for transmitting and receiving radio waves for road-to-vehicle communication with the base station 1. The antenna 21 </ b> C receives radio waves from the base station 1 and supplies the radio waves to the transmission / reception unit 22. Send. As the antenna 21C, it is possible to use an antenna having directivity in a predetermined direction like the antennas 21A and 21B.

  Here, although the three antennas 21A to 21C are provided in the embodiment of FIG. 6, it is also possible to provide only one antenna. In this case, the vehicle 2 Transmission / reception of vehicle-to-vehicle communication with each vehicle in front or rear of the vehicle and transmission / reception of road-to-vehicle communication with the base station 1 are performed.

  In addition, in the case of providing three antennas 21A to 21C or only one antenna, a so-called adaptive antenna that can change the direction of directivity is used as the antenna. Is possible.

  The transmission / reception unit 22 supplies signals received by the antennas 21A to 21C to the communication control unit 24 and the storage unit 26 as necessary under the control of the communication control unit 24. In addition, the transmission / reception unit 22 transmits the output of the mobile station information generation unit 23 or the output of the operation unit 29 supplied via the memory 30 as a radio wave from any of the antennas 21A to 21C. Further, the transmission / reception unit 22 also relays radio waves received by the antennas 21A to 21C. That is, the transmission / reception unit 22 retransmits a signal received by the antenna 21C from the antennas 21A and 21B, or retransmits a signal received by the antennas 21A and 21B from the antenna 21C. In addition, the transmission / reception unit 22 retransmits signals received by the antennas 21A and 21B from the antennas 21B and 21A.

  The mobile station information generation unit 23 generates mobile station information and supplies it to the transmission / reception unit 22. The mobile station information generation unit 23 can be configured using, for example, a GPS (Global Positioning System) system. The communication control unit 24 receives control information supplied from the transmission / reception unit 22 and transmitted from the base station 1, and updates the storage contents of the control information storage unit 25 with the received control information while controlling the control information. Based on the information, the transceiver 22 is controlled. The control information storage unit 25 stores control information supplied from the communication control unit 24. The storage unit 26 includes, for example, a hard disk, a semiconductor memory, and the like, and temporarily stores (accumulates) data such as a movie or other content requested for download supplied from the transmission / reception unit 22. The reproduction control unit 27 refers to the control information stored in the control information storage unit 25 and performs reproduction and control of data stored in the storage unit 26. The output unit 28 displays data to be reproduced by the reproduction control unit 27 or outputs it as sound. The operation unit 29 is operated when requesting downloading or uploading of data or inputting data to be uploaded. The memory 30 temporarily stores data, messages, and the like output when the operation unit 29 is operated, and supplies the data to the transmission / reception unit 22.

  In the mobile station device of the vehicle 2 configured as described above, communication control processing for performing road-to-vehicle communication and vehicle-to-vehicle communication, data reception processing for downloading data, data transmission processing for uploading data, downloaded data A data reproduction process for reproducing the data is performed.

  First, communication control processing will be described with reference to the flowchart of FIG.

  The transmitter / receiver 22 constantly monitors the control channel among the signals received by the antennas 21A to 21C, and when receiving a signal in the frequency band, the antenna 21A for inter-vehicle communication or The received signal is retransmitted as a radio wave from 21B.

  In step S21, the transmitting / receiving unit 22 measures the electric field strength of the received signal in the frequency band of the control channel, proceeds to step S22, and can the control common slot be normally received based on the electric field strength? It is determined whether or not communication with the base station 1 is finally possible using the control common slot.

  If it is determined in step S22 that the control common slot cannot be normally received, that is, if communication with the base station 1 cannot be finally performed using the control common slot, step S21 is performed. Return to.

  Further, when it is determined in step S22 that the control common slot can be normally received, that is, when communication with the base station 1 can be finally performed using the control common slot, In step S23, the mobile station information generation unit 23 generates mobile station information, and the transmission / reception unit 22 arranges the mobile station information in the control common slot and transmits it as a radio wave.

  This radio wave is transmitted to the base station 1 by road-to-vehicle communication between the mobile station device of the vehicle 2 and the base station 1, or road-to-vehicle communication between other vehicles and the base station 1, The data is finally transmitted to the base station 1 while being relayed by one or more other vehicles using the inter-vehicle communication by the other vehicle and the necessary inter-vehicle communication by another vehicle.

  When receiving the mobile station information from the vehicle 2, the base station 1 (the base station apparatus) (FIG. 4) generates the control information as described above, arranges it in the control common slot, and transmits it. In step S24, the transmission / reception unit 22 receives the control information.

  That is, the control information from the base station 1 is transmitted to the vehicle 2 by road-to-vehicle communication between the mobile station device of the vehicle 2 and the base station 1, or the road between the other vehicle and the base station 1 is transmitted. It is finally transmitted to the vehicle 2 while being relayed by one or more other vehicles using inter-vehicle communication, inter-vehicle communication by other vehicles, and further necessary inter-vehicle communication by other vehicles. Therefore, the transmission / reception unit 22 receives the control information transmitted in this manner.

  The control information received by the transmission / reception unit 22 is supplied to the communication control unit 24, and the communication control unit 24 updates the storage content of the control information storage unit 25 with the control information supplied from the transmission / reception unit 22.

  When the control information received in step S24 includes the slot ID of the control individual slot assigned to the vehicle 2, the communication control unit 24 thereafter controls the control individual slot (assignment) of that slot ID. The transmission / reception unit 22 is controlled to exchange mobile station information, control information, and the like with the base station 1 using the slot).

  When the communication control unit 24 updates the control information stored in the control information storage unit 25 as described above, in step S25, a message requesting inter-vehicle communication for the traffic channel in the updated control information. (Hereinafter, referred to as an inter-vehicle communication request message as appropriate) is determined.

  In step S25, when it is determined that the inter-vehicle communication request message is included in the control information, the process proceeds to step S26, and the communication control unit 24 sets the transmission / reception unit 22 to start the inter-vehicle communication for the traffic channel. Control proceeds to step S29.

  As a result, when the transmission / reception unit 22 of the vehicle 2 receives the radio wave of the traffic channel transmitted from the base station 1 or another vehicle, the transmission / reception unit 22 retransmits the traffic channel. It will be relayed to other vehicles. In this way, since the traffic channel is relayed to other vehicles, as described with reference to FIGS. 2B and 2C, the number of vehicles is large. Even if there is a vehicle that cannot enter, data can be downloaded or uploaded using the traffic channel in that vehicle.

  If it is determined in step S25 that the control information does not include the vehicle-to-vehicle communication request message, the process proceeds to step S27, and a message requesting the end of the vehicle-to-vehicle communication for the traffic channel is sent to the control information (hereinafter referred to as “the control information”). It is determined whether or not an inter-vehicle communication end message is included as appropriate.

  If it is determined in step S27 that the inter-vehicle communication end message is included in the control information, the process proceeds to step S28, and the communication control unit 24 performs inter-vehicle communication when performing inter-vehicle communication for the traffic channel. The transmission / reception unit 22 is controlled so as to end the process, and the process proceeds to step S29.

  Thereby, even if the transmission / reception part 22 of the vehicle 2 receives the radio wave of the traffic channel transmitted from the base station 1 or another vehicle, it does not perform the retransmission. That is, for example, when the number of vehicles as shown in FIG. 2 (B) or FIG. 2 (C) is large and the number of vehicles as shown in FIG. There is no other vehicle that should relay radio waves in the vicinity of the vehicle 2, and therefore there is no need to perform vehicle-to-vehicle communication. Therefore, when the transmission / reception unit 22 performs vehicle-to-vehicle communication, the communication control unit 24 The vehicle-to-vehicle communication is terminated.

  On the other hand, if it is determined in step S27 that the inter-vehicle communication end message is not included in the control information, the process proceeds to step S29, and the transmission / reception unit 22 receives the control channel frequency band as in step S21. Measure the field strength of the signal. Further, in step S30, the transmission / reception unit 22 determines whether or not the allocation slot can be normally received based on the electric field strength measured in step S29, that is, using the allocation slot, finally, the base station 1 It is determined whether or not communication is possible.

  If it is determined in step S30 that the allocation slot can be normally received, that is, if it is finally possible to communicate with the base station 1 using the allocation slot, the process returns to step S23. Similar processing is repeated.

  If it is determined in step S30 that the allocation slot cannot be normally received, that is, if communication with the base station 1 using the allocation slot becomes impossible, the process proceeds to step S31, and the communication control unit 24 Determines whether the transmission / reception unit 22 is performing inter-vehicle communication for the traffic channel.

  In step S31, when it is determined that the transmission / reception unit 22 is performing vehicle-to-vehicle communication for the traffic channel, the process proceeds to step S32, and the communication control unit 24 ends the vehicle-to-vehicle communication for the traffic channel. The transmitter / receiver 22 is controlled, and the process proceeds to step S33.

  If it is determined in step S31 that the transmission / reception unit 22 is not performing vehicle-to-vehicle communication for the traffic channel, the process skips step S32 and proceeds to step S33. The transmitter / receiver 22 is controlled so as to end the communication with the station 1, and the process returns to step S21.

  In addition, the base station 1 has, for example, a case where the number of vehicles on the road is small and the vehicle 2 can move from a certain wireless area to the next wireless area in a short time, or the vehicle 2 and immediately before or after When it is not necessary for the vehicle 2 to relay radio waves to other vehicles, such as when the distance between the vehicles is large (when other vehicles cannot receive the radio waves even if they are relayed) In addition, the control information is transmitted including the inter-vehicle communication end message.

  In addition, the base station 1 is, for example, a case where there are a large number of vehicles on a road and it takes time for the vehicle 2 to move from one wireless area to the next wireless area, or the vehicle 2 and the vehicle immediately before or immediately after When the vehicle 2 needs to relay radio waves to other vehicles, such as when the distance between the vehicle and the vehicle is small (when other vehicles can receive the radio waves by relaying radio waves), etc. The control information is transmitted including the inter-vehicle communication request message.

  Next, data reception processing and data transmission processing by the mobile station apparatus of the vehicle 2 will be described with reference to the flowchart of FIG.

  The data reception process and the data transmission process can be performed, for example, when the control individual slot is assigned to the vehicle 2 in the communication control process of FIG.

  When the operation unit 29 is operated to request data download, the operation unit 29 supplies a download request signal corresponding to the operation to the transmission / reception unit 22 via the memory 30. When the download request signal is supplied to the transmission / reception unit 22, the vehicle 2 (mobile station apparatus) performs data reception processing according to the flowchart of FIG.

  That is, first, in step S41, the transmission / reception unit 22 transmits the download request signal in the control individual slot (allocation slot) allocated to the vehicle 2 as the data transfer request message described above. A data transfer request message which is a download request signal from the vehicle 2 is relayed directly or by another vehicle and transmitted to the base station 1.

  As described in FIG. 4, when receiving the data transfer request message for requesting the download, the base station 1 assigns a traffic individual slot to the vehicle 2 and the download is requested using the assigned traffic individual slot. Since the data is transmitted, the communication control unit 24 determines whether or not the data transmitted in this way can be directly received from the base station 1.

  Here, the control information transmitted from the base station 1 also describes an instruction as to whether the vehicle 2 directly receives data from the base station 1 or via a relay by another vehicle. The communication control unit 24 performs the determination process in step S42 based on the control information stored in the control information storage unit 25.

  In step S42, when it is determined that the data can be received directly from the base station 1, for example, when the vehicle 2 is in the radio area of the base station 1, the process proceeds to step S43. The reception output received from the traffic channel by the antenna 21C, which is a communication antenna, is selected and received, and the data arranged in the traffic individual slot assigned to the vehicle 2 is supplied to the storage unit 26, Proceed to step S45.

  If it is determined in step S42 that data cannot be received directly from the base station 1, that is, the vehicle 2 is not in the wireless area, but the radio waves of the base station 1 are relayed by other vehicles. If the radio wave can be received, the process proceeds to step S44, where the transmission / reception unit 22 selects and receives the reception output from which the traffic channel is received by the antenna 21A or B, which is an antenna for inter-vehicle communication. Then, the data arranged in the traffic individual slot assigned to the vehicle 2 is supplied to the storage unit 26, and the process proceeds to step S45. Therefore, for example, even when the vehicle 2 cannot reach the wireless area for a long time due to traffic jams or the like, by receiving radio waves from the base station 1 relayed by other vehicles, You can download it.

  In step S45, the storage unit 26 accumulates the data supplied from the transmission / reception unit 22 in step S43 or 44, and proceeds to step S46.

  In step S46, the communication control unit 24 determines whether or not the control individual slot is still assigned to the vehicle 2 and therefore it is in a state where it can finally communicate with the base station 1. If it is determined that communication is possible, the process returns to step S42, and the same processing is repeated thereafter. By repeating the processes of steps S42 to S46, the data downloaded from the base station 1 is sequentially accumulated in the storage unit 26.

  On the other hand, if the control individual slot assigned to the vehicle 2 is released in the base station 1, and therefore it is determined in step S46 that the vehicle 2 is not communicable with the base station 1, that is, for example, If the vehicle 2 is out of the wireless area and there are no other vehicles around it, the data reception process is terminated.

  Next, data transmission processing will be described.

  For example, when the operation unit 29 is operated, data to be uploaded is input, the data is accumulated in the memory 30, and when the operation unit 29 is operated to request data upload, The operation unit 29 supplies an upload request signal corresponding to the operation to the transmission / reception unit 22 via the memory 30. When the upload request signal is supplied to the transmission / reception unit 22, the vehicle 2 (mobile station apparatus) performs data transmission processing according to the flowchart of FIG. 8B.

  That is, first, in step S51, the transmission / reception unit 22 transmits the upload request signal in the control individual slot (allocation slot) allocated to the vehicle 2 as the data transfer request message described above. A data transfer request message that is an upload request signal from the vehicle 2 is relayed directly or by another vehicle and transmitted to the base station 1.

  As described with reference to FIG. 4, when the base station 1 receives the data transfer request message requesting uploading, the base station 1 assigns the traffic individual slot to the vehicle 2. Therefore, the transmitting / receiving unit 22 uses the assigned traffic individual slot. The data to be transmitted is read from the memory 30.

  In step S52, the communication control unit 24 determines whether the data read from the memory 30 can be directly transmitted to the base station 1.

  Here, the control information transmitted from the base station 1 also describes an instruction as to whether the vehicle 2 transmits data to the base station 1 directly or via a relay by another vehicle. The communication control unit 24 performs the determination process in step S52 based on the control information stored in the control information storage unit 25.

  In step S52, when it is determined that the data can be directly transmitted to the base station 1, for example, when the vehicle 2 is in the wireless area of the base station 1, the process proceeds to step S53. The data read from the memory 30 is transmitted to the antenna 21C, which is a communication antenna, as radio waves, and the process proceeds to step S55.

  If it is determined in step S52 that the data cannot be directly transmitted to the base station 1, that is, the vehicle 2 is not in the wireless area, but the radio waves from the vehicle 2 are relayed to other vehicles. If the data can be transmitted to the base station 1, the process proceeds to step S 54, and the transmitting / receiving unit 22 transmits the data read from the memory 30 as radio waves to the antenna 21 A or B that is an antenna for inter-vehicle communication. Then, the process proceeds to step S55. Therefore, for example, even when the vehicle 2 cannot reach the wireless area for a long time due to traffic jams or the like, data can be uploaded by having other vehicles relay radio waves. .

  In step S55, the communication control unit 24 determines whether or not a control individual slot is still assigned to the vehicle 2, that is, whether or not communication with the base station 1 is finally possible. If it is determined that the communication is possible, the process returns to step S52, and the same processing is repeated thereafter. By repeating the processes of steps S52 to S55, data is uploaded from the vehicle 2 to the base station 1.

  On the other hand, if it is determined in step S55 that the control individual slot assigned to the vehicle 2 is released and therefore the vehicle 2 is not in a state where it can communicate with the base station 1, that is, for example, the vehicle 2 is wireless. When the vehicle is out of the area and there are no other vehicles around it, the data transmission process is terminated.

  Next, for example, when the data reception process of FIG. 8A is started and the data downloaded from the base station 1 starts to be stored in the storage unit 26, when the data is reproducible, Data reproduction processing for reproducing the data is performed.

  That is, in the data reproduction process, as shown in the flowchart of FIG. 9, first, in step S61, as in the case of steps S46 and S55 of FIG. If it is determined whether it is in a state and it is determined that it is not in a communicable state, that is, for example, data download has started in the wireless area, but it has come out of the wireless area and other vehicles are in the vicinity. If you do not exist, or you are out of the wireless area and started downloading data by using relay of radio waves from another vehicle, but you are away from the other vehicle and receive the relayed radio waves When it becomes impossible, step S62 and S63 are skipped and it progresses to step S64.

  If it is determined in step S61 that communication with the base station 1 is possible, the process proceeds to step S62, and the communication control unit 24 performs the same operation as in step S42 in FIG. It is determined whether or not the data transmitted from can be received directly.

  If it is determined in step S62 that the data cannot be received directly from the base station 1, steps S63 to S66 are skipped and the process proceeds to step S67. The reproduction control unit 27 is stored in the storage unit 26. Then, data to be reproduced next is reproduced, supplied to the output unit 28, and the process proceeds to step S68.

  That is, when the vehicle 2 is communicating with the base station 1 but not receiving data directly from the base station 1, the vehicle 2 is not in the wireless area, but the radio waves of the base station 1 are This is a case where the radio wave can be received by being relayed by another vehicle. In this case, as shown in FIG. 2B and FIG. There are traffic jams. Therefore, since the vehicle 2 can receive the radio waves of the base station 1 for a while using relays by other vehicles, even if the data stored in the storage unit 26 is reproduced, Simultaneously with the reproduction, the data can be downloaded from the base station 1 and stored in the storage unit 26, so that the data reproduction is not interrupted (almost).

  Therefore, in this case, while the data is downloaded and stored in the storage unit 26, the stored data is sequentially reproduced.

  On the other hand, if it is determined in step S62 that the data can be received directly from the base station 1, the process proceeds to step S63, and the communication control unit 24 determines whether the data download is completed within the current wireless area. Determine if.

  That is, the case where the vehicle 2 can directly receive data from the base station 1 is the case where the vehicle 2 is in the wireless area of the base station 1, and in step S63, the vehicle 2 travels in that wireless area. While the download of the requested data can be completed.

  Here, the control information transmitted from the base station 1 to the vehicle 2 includes the expected time until the vehicle 2 leaves the wireless area, the remaining amount of data being downloaded, and the like as necessary. Whether the communication control unit 24 can download the remaining amount of the downloaded data within the expected time until the communication control unit 24 leaves the wireless area with reference to such control information. By determining whether or not, the determination process of step S63 is performed.

  In step S63, when it is determined that the data download is completed while the vehicle 2 is traveling in the wireless area of the base station 1, the process proceeds to step S67, and the reproduction control unit 27 is stored in the storage unit 26. The data to be reproduced next is reproduced, supplied to the output unit 28, and the process proceeds to step S68.

  That is, if the data download is completed while the vehicle 2 is traveling in the wireless area of the base station 1, the data reproduction is interrupted even if the data stored in the storage unit 26 is reproduced. (However, as described above, it is assumed that the data to be downloaded is compressed, or the transfer speed for downloading the data is sufficiently faster than the data reproduction speed).

  Therefore, in this case, while the data is downloaded and stored in the storage unit 26, the stored data is sequentially reproduced.

  On the other hand, if it is determined in step S63 that the data download is not completed while the vehicle 2 is traveling in the wireless area of the base station 1, the process proceeds to step S64, and the playback control unit 27 It recognizes the travel time from moving out of the current wireless area to moving to the next wireless area. That is, as described above, the control information includes the travel time from when the vehicle 2 leaves the current wireless area until it moves to the next wireless area. The travel time is recognized by referring to the control information stored in the storage unit 25.

  In step S65, the reproduction control unit 27 obtains an accumulation amount of data stored in the storage unit 26 (a remaining amount of data that has not been reproduced yet), and calculates a reproduction time required for reproducing the data. .

  That is, in this case, the vehicle 2 travels in the wireless area of the base station 1 and receives data directly from the base station 1. Therefore, for example, if the number of vehicles on the road is small and the vehicle 2 is in the state shown in FIG. 2A, the vehicle 2 moves to the next radio area after leaving the radio area of the base station 1. Data cannot be downloaded from the base station 1 until it arrives.

  Further, in this case, since the data download is not completed while the vehicle 2 is traveling in the wireless area of the base station 1, the storage unit is stored when the vehicle 2 leaves the wireless area of the base station 1. 26 is stored only up to the middle of the data to be downloaded.

  Accordingly, when the data stored in the storage unit 26 is reproduced, the data reproduction is interrupted if the vehicle 2 does not arrive at the next wireless area within the time required for reproducing the accumulated data. become.

  Therefore, as described above, when the reproduction control unit 27 recognizes the movement time in step S64 and recognizes the reproduction time in step S65, the reproduction control unit 27 proceeds to step S66 and compares the movement time with the reproduction time. Even if the data stored in the storage unit 26 is reproduced, it is determined whether the reproduction is not interrupted.

  If it is determined in step S66 that the data reproduction is interrupted, that is, if the movement time is longer than (or equal to) the reproduction time, the process returns to step S61, and the same processing is repeated thereafter.

  That is, when there is a possibility that data reproduction is interrupted, the data downloaded and accumulated in the storage unit 26 is not reproduced, and the data continues to be accumulated in the storage unit 26.

  On the other hand, when it is determined in step S66 that the data reproduction is not interrupted, the process proceeds to step S67, where the reproduction control unit 27 reproduces the data to be reproduced next stored in the storage unit 26, and outputs the data to the output unit. 28 and proceeds to step S68.

  That is, when there is no possibility that data reproduction is interrupted, the data downloaded and stored in the storage unit 26 is sequentially reproduced.

  In step S68, the communication control unit 24 determines whether or not the reception of all the data requested to be downloaded has ended. If it is determined that the data has not ended, the communication control unit 24 returns to step S61 and repeats the same processing.

  If it is determined in step S68 that reception of all the data requested to be downloaded has been completed, the process proceeds to step S69, and the reproduction control unit 27 reproduces the remaining data still stored in the storage unit 26. After that, the process ends.

  As described above, since the downloaded data is temporarily stored in the storage unit 26, the data stored in the storage unit 26 is being reproduced even if the data that has not been downloaded is reproduced in a certain wireless area. In addition, when the vehicle 2 arrives at the next wireless area, the data can be reproduced without interruption.

  Therefore, for example, when downloading and playing back time-series data such as video data such as a movie or audio data such as a song, the movie or song can be prevented from being interrupted in the middle. .

  In addition, according to the data download by the data reception process shown in FIG. 8A, when the vehicle 2 directly receives the radio wave from the base station 1 (when performing road-to-vehicle communication), When the radio wave to be relayed is received (when other road-to-vehicle communication and communication using vehicle-to-vehicle communication are performed) may be switched at an arbitrary timing, and data reception is momentarily interrupted at the switching. However, once the downloaded data is stored in the storage unit 26 and then played back, it is possible to prevent such interruption of data reception from affecting the data playback. Can do.

  In the above case, when the data playback is interrupted, the data playback is not started. However, even if the data playback is interrupted, the data It is possible to start playback.

  In addition, for example, as shown in FIG. 2 (A), when the number of vehicles on the road is small, the data is not downloaded from the base station 1 as much as possible. It is possible to download in a certain wireless area as much data as necessary for reproduction in the movement time until moving to the next wireless area.

Furthermore, in step S64, the travel time from when the vehicle 2 leaves the current wireless area to the next wireless area is recognized. For example, as shown in FIG. arrives radio area of the base station 1 ₁ in front of the vehicle 2 ₁ traveling, when the vehicle group is formed, the vehicle 2 _1, the radio area of the base station 1 ₂ which is the next wireless area without, if arriving near the end of the vehicle 2 ₃ of the vehicle group, the radio waves are relayed, it is possible to receive data from the base station 1, the vehicle 2 _1, the base station 1 rather than travel time to move from the _first wireless area to the radio area of the base station 1 _2, a position near the end of the vehicle 2 ₃ of the vehicle group from the radio area of the base station 1 ₁ (vehicle 2 ₃ relays (re The time required to move to the location where you can transmit) You may make it recognize.

  Next, FIG. 10 shows a configuration example of a centralized control device included in the centralized control station 3 of FIG.

The communication I / F 41 receives information transmitted from each of the base stations 1 ₁ , 1 ₂ ,..., Supplies the information to the control unit 42, and is transmitted from a certain base station under the control of the control unit 42. The received information is transmitted to other base stations. Further, the communication I / F 41 transmits data requested to be downloaded from the vehicle 2 through the base station 1 to the base station 1 under the control of the control unit 42.

  The control unit 42 controls the communication I / F 41 to transmit the information transmitted from a certain base station to another base station, or the data requested to be downloaded from the vehicle 2 through the base station 1. , Read from the database 43 and transmit to the base station 1.

  Note that the central control device of the central control station 3 is configured in the same manner as the calculation unit 14 or the control information generation unit 15 provided in the base station device of the base station 1 in FIG. 4, as indicated by a dotted line in FIG. The calculation unit 44 or the control information generation unit 45 can be further provided.

In this case, the calculation unit 44 or the control information generation unit 45 is respectively connected to the calculation unit 14 or the control information generation unit 15 of FIG. 4 based on the information transmitted from each base station 1 ₁ , 1 ₂ ,. Similar processing is performed to obtain control information. Then, the control unit 42 controls the communication I / F 41 to transmit the control information to each base station 1 ₁ , 1 ₂ ,..., And each base station 1 ₁ , 1 ₂ ,. Performs processing using the control information. In this case, the base station apparatus of the base station 1 can be configured without providing the calculation unit 14 and the control information generation unit 15.

  FIG. 11 shows a configuration example of another embodiment of a communication system to which the present invention is applied.

In the embodiment of FIG. 11A, the base stations 1 ₁ ′, 1 ₂ ′,... Can communicate directly with each other. Further, in the embodiment of FIG. 11A, the central control station 3 is not provided, so that the base stations 1 ₁ ′, 1 ₂ ′,. It has functions corresponding to the database 43, the calculation unit 44, and the control information generation unit 45.

On the other hand, in the embodiment of FIG. 11B, the basic configuration is the same as in FIG. 1, but the central control station 3 ′ corresponds to the calculation unit 44 and the control information generation unit 45 of FIG. The base stations 1 ₁ ″, 1 ₂ ″,... Each have functions corresponding to the control unit 42 and the database 43 in FIG.

  Next, the series of processes described above can be performed by hardware or software. When a series of processing is performed by software, a program constituting the software is installed in a general-purpose computer or the like.

  Therefore, FIG. 11 shows a configuration example of an embodiment of a computer in which a program for executing the series of processes described above is installed.

  The program can be recorded in advance in a hard disk 105 or a ROM 103 as a recording medium built in the computer.

  Alternatively, the program is stored temporarily on a removable recording medium 111 such as a floppy disk, a CD-ROM (Compact Disc Read Only Memory), an MO (Magneto optical) disc, a DVD (Digital Versatile Disc), a magnetic disc, or a semiconductor memory. It can be stored permanently (recorded). Such a removable recording medium 111 can be provided as so-called package software.

  The program is installed in the computer from the removable recording medium 111 as described above, or transferred from the download site to the computer wirelessly via a digital satellite broadcasting artificial satellite, LAN (Local Area Network), The program can be transferred to a computer via a network such as the Internet, and the computer can receive the program transferred in this way by the communication unit 108 and install it in the built-in hard disk 105.

  The computer includes a CPU (Central Processing Unit) 102. An input / output interface 110 is connected to the CPU 102 via the bus 101, and the CPU 102 operates an input unit 107 including a keyboard, a mouse, a microphone, and the like by the user via the input / output interface 110. When a command is input as a result, the program stored in a ROM (Read Only Memory) 103 is executed accordingly. Alternatively, the CPU 102 also transfers from a program stored in the hard disk 105, a program transferred from a satellite or a network, received by the communication unit 108 and installed in the hard disk 105, or a removable recording medium 111 attached to the drive 109. The program read and installed in the hard disk 105 is loaded into a RAM (Random Access Memory) 104 and executed. Thus, the CPU 102 performs processing according to the above-described flowchart or processing performed by the configuration of the above-described block diagram. Then, the CPU 102 outputs the processing result from the output unit 106 configured with an LCD (Liquid Crystal Display), a speaker, or the like via the input / output interface 110, or from the communication unit 108 as necessary. Transmission and further recording on the hard disk 105 are performed.

  Here, in the present specification, the processing steps for describing a program for causing the computer to perform various processes do not necessarily have to be processed in time series in the order described in the flowcharts, but in parallel or individually. This includes processing to be executed (for example, parallel processing or processing by an object).

  Further, the program may be processed by one computer or may be distributedly processed by a plurality of computers. Furthermore, the program may be transferred to a remote computer and executed.

  In addition to transmission / reception of video data and audio data, the present invention includes text data, computer program, screen data described in HTML (Hyper Text Markup Language), traffic information, maps used in a car navigation system, and the like. It can also be applied to transmission and reception of information and the like.

  The present invention can also be applied to ITS (Intelligent Transport System) and the like.

  Further, in the present embodiment, the travel time of the vehicle 2 is obtained at the base station 1 and is included in the control information and transmitted to the vehicle 2. However, the travel time of the vehicle 2 is It is also possible to receive necessary information from the base station 1 and obtain it based on the information.

  In this embodiment, the TDMA communication is performed between the base station 1 and the vehicle 2, but the communication method between the base station 1 and the vehicle 2 is limited to the TDMA method. For example, CSMA / CD (Carrier Sense Multiple Access with Collision Detection) or the like can be adopted.

  DESCRIPTION OF SYMBOLS 1 Base station, 2 Vehicle, 3 Centralized control station, 11 Antenna, 12 Transmission / reception part, 13 Measurement part, 14 Calculation part, 15 Control information generation part, 16 Request processing part, 17 Communication I / F, 21A thru | or 21C Antenna, 22 Transmission / reception unit, 23 Mobile station information generation unit, 24 Communication control unit, 25 Control information storage unit, 26 Storage unit, 27 Playback control unit, 28 Output unit, 29 Operation unit, 30 Memory, 41 Communication I / F, 42 Control unit , 43 database, 44 operation unit, 45 control information generation unit, 101 bus, 102 CPU, 103 ROM, 104 RAM, 105 hard disk, 106 output unit, 107 input unit, 108 communication unit, 109 drive, 110 input / output interface, 111 Removable recording medium

Claims (16)

A mobile communication device that performs wireless communication with a base station,
Relay communication means for performing relay communication, which is communication for relaying wireless communication between a base station arranged so that wireless areas capable of wireless communication are discrete, and other communication devices,
And a communication control means for controlling whether or not to perform the relay communication based on predetermined control information. When the control information is transmitted from the base station,
The communication apparatus according to claim 1, further comprising receiving means for receiving the control information transmitted from the base station. The communication apparatus according to claim 1, wherein the base stations are arranged on a road expressed in a one-dimensional manner so that wireless areas are discrete. A communication method for performing wireless communication with a base station,
A relay communication step for performing relay communication, which is communication for relaying wireless communication between a base station arranged so that wireless areas capable of wireless communication are discrete and a movable communication device;
A communication control step for controlling whether or not to perform the relay communication based on predetermined control information. A recording medium in which a program for causing a computer to perform communication processing for performing wireless communication with a base station is recorded,
A relay communication step for performing relay communication, which is communication for relaying wireless communication between a base station arranged so that wireless areas capable of wireless communication are discrete and a movable communication device;
A recording medium comprising: a communication control step for controlling whether to perform the relay communication based on predetermined control information. A communication device that communicates with a mobile station that is movable,
Recognition means for recognizing the state of the mobile station;
Generation means for generating control information for controlling whether a predetermined mobile station performs relay communication, which is communication for relaying wireless communication with another mobile station, based on the state of the mobile station When,
A communication device comprising: transmission means for transmitting the control information. 7. The communication device according to claim 6, wherein wireless communication areas capable of wireless communication with the mobile station are arranged so as to be discrete. 8. The communication apparatus according to claim 7, wherein the wireless areas are arranged so as to be discrete on a road expressed one-dimensionally. 7. The communication apparatus according to claim 6, wherein the recognizing unit recognizes a state of the mobile station based on information transmitted from the mobile station. A communication method for communicating with a movable mobile station,
A recognition step for recognizing the state of the mobile station;
A generation step of generating control information for controlling whether or not to allow a predetermined mobile station to perform relay communication, which is communication for relaying wireless communication with another mobile station, based on the mobile station information; ,
And a transmission step of transmitting the control information. A recording medium in which a program for causing a computer to perform communication processing for communication with a mobile station that is movable is recorded,
A recognition step for recognizing mobile station information about the mobile station;
A generation step of generating control information for controlling whether or not to allow a predetermined mobile station to perform relay communication, which is communication for relaying wireless communication with another mobile station, based on the mobile station information; ,
A recording medium comprising: a transmission step for transmitting the control information. A communication device mounted on a vehicle that performs wireless communication with a base station,
Direct communication by a first communication device that performs direct communication, which is direct communication with a base station arranged so that wireless areas capable of wireless communication are discrete;
Communication means for performing wireless communication with the base station by using the relay communication by a second communication device that performs relay communication that is communication for relaying wireless communication with the base station. A communication device. The communication device according to claim 12, wherein the first and second communication devices are the same or different communication devices. The communication apparatus according to claim 12, wherein the base stations are arranged on a road expressed in a one-dimensional manner so that wireless areas are discrete. A communication method of a communication device mounted on a vehicle that performs wireless communication with a base station,
Direct communication by a first communication device that performs direct communication, which is direct communication with a base station arranged so that wireless areas capable of wireless communication are discrete;
A communication step of performing wireless communication with the base station using the relay communication by a second communication device that performs relay communication, which is communication that relays wireless communication with the base station. Communication method. A recording medium in which a program for performing communication processing in a communication device mounted on a vehicle that performs wireless communication with a base station is recorded,
Direct communication by a first communication device that performs direct communication, which is direct communication with a base station arranged so that wireless areas capable of wireless communication are discrete;
A program comprising a communication step of performing wireless communication with the base station using the relay communication by a second communication device that performs relay communication, which is communication that relays wireless communication with the base station, is recorded. A recording medium characterized by that.

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