JP2002044005A - Road-to-vehicle communication system - Google Patents

Abstract

(57) [Summary] In a road-to-vehicle communication system performed between a base station device installed on a road and a mobile station device mounted on a vehicle, a data transmission rate to the mobile station device is improved and uniformity is improved. Perform data transfer. A dividing unit (121) of a base station device (100) divides application data addressed to a mobile station device in road-to-vehicle communication.
, The message data slot constituting the one communication frame is divided into vacant slots so that data addressed to the same mobile station device 200 is stored and used. The data is distributed according to the number of message data slots to be transmitted, and the data to each mobile station device is multiplexed by the multiplexing means.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automobile communication system, and more particularly to a road-to-vehicle communication system constructed by a mobile station device mounted on a vehicle and a base station device installed on a road, and a mobile station device used therefor. And a base station device.

[0002]

2. Description of the Related Art In order to realize services aimed at improving safety, improving transportation efficiency, and improving comfort, an intelligent transportation system (ITS: I) that integrates a road and a vehicle.
ntelligent Transport Systems) is under development. This system provides various communication services by road-to-vehicle communication performed between a base station device installed on a road and a mobile station device mounted on a vehicle and inter-vehicle communication performed between mobile station devices. , ARIB STD-
There is a system described in "T55" (established on November 27, 1997). The above standard defines the configuration of road-to-vehicle communication by spot communication with a limited communication zone, and different frequencies are used for downlink communication from the base station device to the mobile station device and uplink communication from the mobile station device to the base station device. As the full-duplex communication (base station apparatus) to be used, adaptive slotted aloha, which is synchronous time-division communication in which a communication frame is time-divided into fixed-length sections called slots, is employed.

[0003] A communication frame of the adaptive slotted Aloha has a communication slot and a control slot. The communication slot includes a message data slot (MDS) for exchanging data between road and vehicle so that communication with a plurality of mobile station devices is possible. : Message Data Slot). Further, the control slot includes control information necessary for road-to-vehicle communication, and stores a frame control message slot (FCMS: Frame Control Message) for storing configuration information of a communication frame transmitted by the base station apparatus and usage status of the communication slot.
Slot) and an activation slot (AC) for the mobile station device to request the base station device to allocate a communication slot.
TS: Activation Slot). There is no concept of a mobile station device for a communication slot, and a plurality of message data slots in one communication frame are occupied by data addressed to one mobile station device in a specification in which a communication slot is not occupied by a specific mobile station device. It is possible to

FIG. 9 is a diagram for explaining a configuration example of a conventional road-vehicle communication system. The road-to-vehicle communication means is, for example, 1
When the number of message data slots constituting the communication frame is set to 8, and very large data (application data 903) is transferred from the application means 902 of the base station apparatus 901 to the mobile station apparatus 910, the path of the base station apparatus 901 is set. Division means 906 of inter-vehicle communication means 905
Then, the application data is divided into a size that can be stored in one message data slot, one message data slot in one communication frame is occupied by one mobile station device 910 and transmitted, and the assembling means 91 of the road-to-vehicle communication means 911 is transmitted.
After assembling the data in step 2, the application means 91
3 has been notified.

[0005]

According to the above prior art, when very large data is received from the application means, data division occupies one message data slot in one communication frame, and an empty message data slot occurs. Was.

An object of the present invention is to avoid using the dividing means of the road-to-vehicle communication means and, when the number of mobile station apparatuses is equal to or less than the number of message data slots constituting one communication frame, to transmit an empty message data slot at present. In order to improve the transmission rate by allocating data to the mobile station devices in the middle, by multiplexing data corresponding to the mobile station devices, data transfer is performed evenly to all mobile station devices, and the number of mobile station devices is reduced. A communication system in which when the number of message data slots constituting one communication frame is larger than the number of message data slots, the number of message data slots is used to control data addressed to the mobile station device, thereby preventing the transmission rate from dropping below the conventional transmission rate; And its base station device,
A mobile station device is provided.

[0007]

In order to solve the above problems, a road-vehicle communication system of the present invention for providing information to a base station apparatus and one or more mobile station apparatuses is connected to the base station apparatus. Dividing means for dividing the data into mobile station devices, and creating a transmission queue capable of registering the data divided for each mobile station device, assembling the divided data divided by the dividing means into the mobile station device; Assembly means was provided.

[0008] Then, at least the slot queue of at least the number of slots arranged in one communication frame in the base station apparatus, and one communication frame when the mobile station apparatus becomes equal to or more than the number of slots constituting one communication frame. Distribution means for scheduling data transfer to the mobile station device with the number of slots configured is provided to prevent the connected mobile station device from lowering below the conventional transmission speed of the wireless communication zone.

When transmission data is transmitted from the base station apparatus to a plurality of mobile station apparatuses, the base station apparatus is provided with a multiplexing means for sequentially allocating data to each mobile station apparatus in slot units. Was configured to transfer data evenly.

The dividing means includes a dividing flag indicating that the data has been divided into divided data units, a final flag indicating the presence / absence of continuous data, a PDU number which is a serial number of the divided data, an application data The configuration is such that a group number, which is a serial number of the unit, is added.

[0011] The multiplexing means may be configured to allocate data to each mobile station device for each slot.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the configuration and operation of a road-vehicle communication system according to the present invention and a base station apparatus and a mobile station apparatus used in the system will be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing a configuration of a road-vehicle communication system according to the present invention and a base station apparatus and a mobile station apparatus used therein. In the figure, 100 is a base station device, 11
0 is application means of the base station apparatus, 120 is transfer control means of the base station apparatus, 130 is road-vehicle communication means of the base station apparatus, 140 and 150 are mobile station apparatuses, 141 is road-vehicle communication means of the mobile station, and 145 is Mobile station transfer control means, 1
47 is an application means of the mobile station. In the road-to-vehicle communication system according to the present embodiment, the base station device 100 includes:
It is assumed that a spot-like communication zone is fixedly formed on the road, and a communication path by wireless communication is provided to the mobile station devices 140 and 150.

The base station apparatus 100 includes at least a transfer control means 120 for performing relay control of a communication packet of the application means 110 exchanged with the mobile station apparatuses 140 and 150, and a wireless communication connection with the mobile station apparatus. Transfer control means 12 for performing an information communication.
0 and the road-to-vehicle communication means 130 provided for the vehicle.

The mobile station device 140 includes at least a transfer control unit 145 for performing relay control of a communication packet of the application unit 147 exchanged with the base station device 100, and a base station device installed on the roadside. And a road-to-vehicle communication unit 141 that provides an interface for performing wireless communication connection and information communication to the transfer control unit 145.

In the figure, reference numeral 121 denotes a dividing means of the transfer control means of the base station apparatus, 122 denotes a distribution means of the transfer control means of the base station apparatus, and 123 denotes multiplexing of the transfer control means of the base station apparatus. Means 146 indicate assembling means of the transfer means of the mobile station apparatus.

Next, an example of the configuration and operation of the transfer control means provided in the base station apparatus and the mobile station apparatus constituting the road-vehicle communication system of the present embodiment will be described. The dividing means 121 of the transfer control means of the base station apparatus shown in FIG. 1 is adapted to store the transmission data addressed to the application means 147 of the mobile station apparatus 140 requested to be transmitted by the application means 110 in one message slot by the road-vehicle communication means 130. As shown in the packet configuration diagram of FIG. 6, the divided data unit includes a division flag 602, a final flag 603, a PDU number 604 which is a serial number of the divided data unit, and a group number which is a serial number of the application data unit. 605 is edited into the data to which each is assigned, and FIG.
The queue is registered in the transmission queue 701 managed for each mobile station device as shown in FIG.

Note that the last flag 603 in FIG. 6 indicates the presence of data that has been continuously turned off, and that the on flag indicates that it is the last data (or single data). The division flag 602 is a flag indicating whether or not the application data is divided, where ON means divided data and OFF means no division. PDU number 604
Is a serial number in units of divided data, and is used to grasp the order of the divided data at the time of assembling the data of the transfer control means 145 provided in the mobile station apparatus 140. Group number 60
Reference numeral 5 denotes a serial number in application data units, which is used to identify application data when data is assembled by the transfer control means 145 provided in the mobile station apparatus 140.

FIG. 2 shows a dividing means 121 provided in the transfer control means of the base station apparatus used in the road-vehicle communication system of the present invention.
6 is a flowchart showing the operation of the first embodiment. Dividing means 121
From the application means 110 to the mobile station device 140
Request event addressed to application means 147 of
When (201) is notified, the division start flag is turned off.
After performing (202), it is determined whether the size of the application data indicated by 601 in FIG. 6 can be stored in one message slot of the road-to-vehicle communication unit 130 (203).

When the size of the application data is larger than the size that can be stored in one message slot of the road-to-vehicle communication means 130, the division flag 602 is turned on, the final flag 603 is turned off, the PDU number 604 which is a serial number of the division data unit, and the application data. A group number 605, which is a serial number of a data unit, is set (2
04) Then, the transmission queue 7 of the application data
The edited size is edited (205) and the edited size is updated (206).

The edited application data is registered (207) in the transmission queue 701 managed for each mobile station device shown in FIG. 7 (207), and a division start flag indicating that division has started is turned on (208). I do. Thereafter, the above processing is repeatedly performed until the application data becomes smaller than the size that can be stored in one message slot.

If the size of the application data is smaller than the size that can be stored in one message slot of the road-to-vehicle communication procedure 130, it is determined (209) that the division start flag indicating that division has been started is on, and If the division start flag indicating that the start has been started is on, the division flag 602 is turned on and the final flag 603 is set on.
(210) If the division start flag indicating that the division has been started is off, the division flag 602 is set to off and the final flag 603 is set to on (211), and the application data is edited (212). After that, it is registered in the transmission queue 701 (213), and the distribution means 122 of the transfer control means of the base station apparatus is used in the slot assignment request event (214) to activate the distribution means 122 of the transfer control means of the base station apparatus. Start

FIG. 3 shows a distribution means 122 provided in the transfer control means of the base station apparatus used in the road-vehicle communication system of the present invention.
6 is a flowchart showing the operation of the first embodiment. The distributing unit 122 of the present invention prepares the slot queue 801 shown in FIG. 8 by the number of message slots arranged in one communication frame by the road-to-vehicle communication unit 130, and divides the slot queue into transmission queues. Set data in application data units. When all the slot queues are used by the transmission queue, the transmission queue 701 waits until the slot queue becomes empty.

When the distribution means 122 of the present invention is activated by a slot allocation request (301) from the division means 121 of the transfer control means of the base station apparatus, it secures an empty slot queue (302), and secures it. Determine if successful (3
03). If the reservation is successful, the transmission data is extracted from the transmission queue 701 in application data units and registered in the slot queue 801 (304). If the reservation fails, the transmission queue is temporarily waited (305) while the slot queue release instruction (306) is issued from the multiplexing means 123 of the transfer control means of the base station apparatus.

Multiplexing means 1 of transfer control means of the base station apparatus
When activated by the slot queue release instruction (306) from 23, the slot queue is first released (307).
Next, it is determined by 305 whether or not waiting has occurred (308). If waiting has occurred, transmission data is taken out of the waiting transmission queue and registered in the slot queue (309). Note that nothing is done if the waiting has not occurred.

According to the multiplexing means 123 of the transfer control means of the base station apparatus shown in FIG. 1, the application data divided by the dividing means 121 and the distribution means 122 of the transfer control means of the base station apparatus and registered in the slot queue are divided. The data is multiplexed with the transmitted data and transmitted to the road-to-vehicle communication means 130 of the base station apparatus 100.

FIG. 4 shows a multiplexing means 12 provided in the transfer control means of the base station apparatus used in the road-vehicle communication system of the present invention.
6 is a flowchart showing the operation of No. 3. The multiplexing means 123 of the present invention is activated when the transmission period elapses (401),
Retrieve transmission data from slot queue 801 (403)
And transmits it to the road-vehicle communication means 130 of the base station apparatus 100.
(404). It is determined (405) whether or not all the transmission data of the slot queue has been transmitted. If all the data has been transmitted, the distribution unit 122 instructs the distribution unit 122 to release the slot queue so that the slot queue is allocated to the next transmission queue.
(406) is notified. The slot queue to be transmitted is sequentially updated (407), and the process is performed until transmission data in all slot queues is exhausted (402).

The road-to-vehicle communication means 130 provided in the base station apparatus of the present invention is already divided by the transfer control means 120 and has a size that can be stored in one message data slot. Instead, the road-to-vehicle communication control information (606 in FIG. 6) is added to the application data, stored in one message slot, and notified to the road-to-vehicle communication means 141 of the mobile station apparatus 140 through the wireless section.

The road-to-vehicle communication means 141 provided in the mobile station apparatus of the present invention extracts a message slot addressed to the own mobile station apparatus from the frame, and performs road-to-vehicle communication control information (FIG. 6, 60).
7) is removed and the reception is notified to the assembling means 146 provided in the transfer control means of the mobile station device.

FIG. 5 shows the assembling means 146 provided in the transfer control means of the mobile station apparatus used in the road-vehicle communication system of the present invention.
6 is a flowchart showing the operation of the first embodiment. The assembling means 146 of the present invention assembles the data received from the road-to-vehicle communication means 141 into application data (612 in FIGS. 6 and 6) using the division flag 608 and the final flag 609, and the application means 147 of the mobile station apparatus. To the data reception.

The assembling means 146 of the present invention determines (502) whether the data is divided by the division flag 608. If the data is divided data as a result of the determination, the data notified in random order by the road-to-vehicle communication means 141 of the mobile station device 140 is assembled into application data by the PDU number 610, the group number 611, and the final flag 609 (503). I do.

When the last flag 608 is turned on (final data), all Ps of the same group number 611 before the last data are received.
When the DU is received, it is determined that the assembly is completed (504), and the application unit 147 of the mobile station device is notified of the data reception (505).

In the case of no division, the division flag 60
8, remove the final flag 609, the PDU number 610, and the group number 611, and notify the application means 147.
(505).

As described above, by using the transfer control means provided in the base station apparatus or the mobile station apparatus of the road-vehicle communication system of the present invention,
The dividing means of the road-to-vehicle communication means is not used, and when the number of mobile station devices is equal to or less than the number of message data slots constituting one communication frame, an empty message data slot is allocated to the currently communicating mobile station device. By increasing the transmission rate and multiplexing data corresponding to mobile station devices, data transfer is performed evenly to all mobile station devices, and the number of mobile station devices is larger than the number of message data slots constituting one communication frame. In this case, by controlling the data addressed to the mobile station device by the number of message data slots, it is possible to prevent the transmission rate from lowering below the conventional transmission rate.

According to the dividing means and the assembling means provided in the transfer means of the present invention, since the dividing means and the assembling means of the road-to-vehicle communication means are not used, the mobile station apparatus having the number of message data slots constituting one communication frame or less is used. When the data transfer is performed, an empty message data slot of the message data slot constituting one communication frame can be used, and the conventional data transfer time can be reduced.

[0036] Further, even when the mobile station device has the number of message data slots constituting one communication frame or more, the distributing means provided in the base station device can provide the mobile station with the number of message data slots constituting one communication frame. By limiting the data transfer to the device, it is possible to prevent the transmission rate from lowering below the conventional value.

The multiplexing means provided in the base station device can perform uniform data transfer to a plurality of mobile station devices.

[0038]

According to the present invention, since data is divided into a size that can be stored in the message data slot and transmitted to the mobile station device, all the message data slots constituting one communication frame are valid. Can be used to improve the data transmission rate to the mobile station device, and, if the number of mobile station devices is equal to or greater than the number of message data slots constituting one communication frame,
Since the limitation by the number of slots is implemented, it is possible to prevent the data transmission speed from being lower than the conventional data transmission speed,
Further, data can be transferred evenly to a plurality of mobile station devices.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a system configuration example of a road-vehicle communication system of the present invention.

FIG. 2 is a flowchart showing the operation of a dividing unit provided in the base station apparatus.

FIG. 3 is a flowchart showing the operation of a distribution unit provided in the base station apparatus.

FIG. 4 is a flowchart showing the operation of the multiplexing means provided in the base station apparatus.

FIG. 5 is a flowchart showing the operation of the assembling means provided in the mobile station apparatus.

FIG. 6 is a signal configuration diagram showing a configuration of a communication packet used in the road-vehicle communication system of the present invention.

FIG. 7 is an explanatory diagram showing a configuration of a transmission queue managed by the base station apparatus.

FIG. 8 is an explanatory diagram showing a configuration of a slot queue managed by the base station apparatus.

FIG. 9 is an explanatory diagram showing a configuration example of a conventional road-vehicle communication system.

[Explanation of symbols]

100 ... base station apparatus, 110, 147 ... application means, 120, 145 ... transfer control means, 1
21 ... division means, 122 ... distribution means, 123 ... multiplexing means, 130, 141 ... road-vehicle communication means, 14
0 ... Mobile station device, 146 ... Assembling means.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H04L 13/08 H04B 7/26 105D // G08G 1/09 H04L 11/00 310B (72) Inventor Toshiyuki Sakamoto 292 Digital Media Development Division, Hitachi, Ltd., Hitachi, Ltd.Digital Media Development Division, Hitachi, Ltd. (72) Inventor Tetsuo Nakano 292 Digital Media Development Division, Hitachi, Ltd., Yoshida-cho, Totsuka-ku, Yokohama, Kanagawa, Japan (72) Inventor Naoyoshi Fujii 890 Kashimada, Saiwai-ku, Kawasaki City, Kanagawa Prefecture Inside the Social & Network Systems Division, Hitachi, Ltd. Within the business division (72) Inventor Shinichi Sugimoto Kanagawa 180F Totsuka-cho, Totsuka-ku, Yokohama-shi F-term (reference) 5H180 AA01 BB04 BB17 5K028 AA11 BB04 CC03 CC05 DD01 DD02 EE09 HH02 HH03 LL44 SS24 5K033 AA01 BA06 CA13 CB13 DA01 DA19 DB16 DB17 5K03ABB CC06 DD02 HH01 HH02 HH12 HH14 HH17 HH54 MM08 MM25 5K067 AA12 BB21 CC08 EE02 EE10 EE71 GG03 HH21

Claims (5)

[Claims] 1. A road-to-vehicle communication system for providing information from a base station apparatus to one or more mobile station apparatuses, wherein data is divided for each mobile station apparatus connected to the base station apparatus, A dividing means for creating a transmission queue capable of registering data divided for each station device; and assembling means for assembling the divided data divided by the dividing means in the mobile station device. Inter-vehicle communication system. 2. The system according to claim 1, wherein the base station device has a slot queue of at least the number of slots arranged in one communication frame, and one communication frame when the mobile station device has the number of slots constituting one communication frame or more. Distribution means for scheduling data transfer to the mobile station device with the number of slots constituting the device, so as to prevent the connected mobile station device from lowering below the conventional transmission speed of the wireless communication zone. The road-to-vehicle communication system according to claim 1, wherein: 3. When there is transmission data from the base station apparatus to a plurality of mobile station apparatuses, the base station apparatus is provided with a multiplexing means for sequentially allocating data to each mobile station apparatus in slot units. The road-to-vehicle communication system according to claim 1, wherein data is uniformly transferred to the station device. 4. The division means includes: a division flag indicating that data has been divided into divided data units; a final flag indicating the presence or absence of continued data; a PDU number which is a serial number of the divided data; The road-vehicle communication system according to claim 1, wherein a group number that is a serial number of a data unit is added. 5. The road-vehicle communication system according to claim 3, wherein said multiplexing means allocates data to each mobile station device for each slot.