JPH02301393A - Traffic management system - Google Patents

Abstract

PURPOSE:To surely receive each data by deciding overlapped data when the data are overlapped in the case of the transmission with the contention system and sending the data again with a prescribed time difference based on the result of decision. CONSTITUTION:When position beacon receivers 6, 6 of vehicles A, B receive the position data from beacon receivers 15, 15, the data A, B are sent to a base station to awaits the reply from a management center 21 for a prescribed time. When the management center 21 receives the data A, B, whether or not the data A, B are overlapped or not is decided. As a result of decision, when the data A, B are overlapped, a retrial signal is sent to the radio equipments 5, 5 of the vehicles A, B and each radio equipment sends each data again at a time difference. Thus, even when the data are overlapped, each data is surely received.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a traffic control system for vehicles such as buses that travel on a predetermined route, and in particular, to a traffic control system for vehicles such as buses that travel on a predetermined route. related to the traffic control system.

[Prior art]

Recently, route buses communicate wirelessly with the bus stop and the control center, and various data from the bus and the bus stop are sent to the control center, while the control center issues various commands to the bus and the bus stop. There is a system that controls the operation of buses. When a command is issued from the control center, the bus is able to operate according to the command,
At the bus stop, the bus's destination, waiting time, and other operating conditions are displayed on a display device, and the control center monitors the status of the bus and the bus stop.

[Problem to be solved by the invention]

By the way, when collecting data from route buses and bus stops to the control center, either a polling method in which data is transmitted in response to a call signal from the control center or a contention method in which data is transmitted in the order of transmission is used. However, although the contention method is instantaneous and is excellent at exchanging data with moving vehicles, as the number of vehicles increases, multiple pieces of data are received at the same time, and multiple pieces of data overlap and are This poses the problem of not being able to receive data accurately as it may not be possible to receive the same information accurately.

The present invention was devised in view of the above circumstances, and aims to provide a traffic control system that can reliably collect each piece of data even when data overlaps.

[Means to solve the problem]

In order to achieve the above object, the present invention provides a traffic control system that performs contention-based communication between a base station and a plurality of vehicles, and which transmits data from a wireless device mounted on each of the vehicles. means for determining overlap; retry means for causing each of the wireless devices to transmit each data again when the data overlap; and means for setting a time difference between retransmissions of each data by the retry means. Configured.

[Operation] According to the configuration of the present invention, when data from the wireless devices installed in each vehicle overlap, this overlap is determined by the determining means, and based on the determination result, the retry means assigns a time difference to each wireless device. and retransmit each data.

〔Example〕

The present invention will be explained based on an embodiment shown in the drawings.

Fig. 1 is a block diagram showing the circuit configuration, Fig. 2 is a bus route map, Fig. 3 is a flowchart showing the control operation of the vehicle side control unit, and Figs. It is a flowchart which shows the control operation of a control unit.

The traffic control system of the present invention generally includes a vehicle-side control system 1 mounted on a vehicle such as a route bus, a stop-side control system 11 disposed at a bus stop, and a vehicle-side control system 1 mounted on a vehicle such as a route bus.
The traffic control center 21 issues traffic commands and performs traffic control.

The vehicle-side control system 1 includes a vehicle-side control unit 2 that controls various devices, a card reader 4 that drives a route memory card 3, a vehicle-side wireless device 5 that communicates with the control center 21, and a position beacon. A receiver 6, a distance sensor 7 that detects the distance traveled by the vehicle, and a display device 8 that displays data are connected to each other.

The vehicle-side control unit 2 is composed of a normal computer and performs control based on a control program.
In particular, the communication method is switched between a polling method in which communication is performed with the vehicle-side wireless device 5 in the order of calling signals, and a contention communication method in which communication is performed in the order of transmission. In other words, the contention method is originally desirable because data from moving vehicles needs to be instantaneous, but if the contention communication method alone becomes too large, the data overlaps and the data cannot be downloaded. In consideration of this, areas where vehicles are congested (see A zone in Figure 2), i.e.
The contention method is used in areas with high traffic volume, while in areas where vehicle congestion is eased (see Zone B in Figure 2), immediacy is not significantly impaired even if the traffic volume is low and communication is carried out in the order of calls. It was decided to use a polling method in the region. In addition, the vehicle-side control unit 1 performs memory for transmission and reception data, processing of data allocation, transmission/reception and verification functions of vehicle ID numbers, etc., and processing of locations between buses. Variable fixed data necessary for route and vehicle management, such as timetable data and distance data between stops, is stored. Further, the position beacon receiver 6 receives absolute position information and machine number ID from a position beacon transmitter ta15, which will be described later. This absolute location information and aircraft number! Based on D, the vehicle-side control unit 2 not only switches the communication method of the vehicle-side wireless device 5 but also causes the traffic control center 21 to transmit the system, route, company name, code, etc. This transmission data is transmitted to the stop-side wireless device 13 of the stop-side control system 11 as described later.
intercepts it.

On the other hand, the stop-side control system 11 includes a stop-side control unit 12 that performs various controls, and a stop-side radio device 13 consisting of a multi-channel access radio (MCA).
and a display device 14 are connected thereto, and is also equipped with an Isaka beacon transmission vi15.

The stop-side control unit 12 is composed of a normal computer, and controls the stop-side wireless device 13 based on a control program.
It has a buffer memory function for data from 3. Further, the stop-side wireless device 13 receives various command data from the control center 21 under the control of the control unit 12 .

Further, the display device 14 displays data from the vehicle-side control system 1 and the control center 21, such as the destination of the next bus, time, overtaking state, etc., and provides it to waiting passengers. In addition, the position beacon transmitter 15 is placed in the Samurai at the boundary line C between zone A and zone B in FIG. Based on this position information, the vehicle system, company name, code, etc. are transmitted from the vehicle-side wireless device 5 to the control center 21. This transmission data is intercepted by the stop-side wireless device 13, and when the stop-side control unit 12 determines that the communication is addressed to itself, a predetermined destination light is displayed on the display device 1.
4 are displayed in the order received. When the bus arrives and the door is opened or closed, the display shifts to the next destination and blinks while passengers are getting on and off.

In addition, the control unit provided in the control unit 2 and the control center 21 determines when data is simultaneously transmitted from the vehicle-side wireless devices 5 of multiple vehicles while communicating by the contention method, and uses a random number. The data is retransmitted after a certain time difference due to the occurrence of the error.

Next, the control operations of the control unit 2.12 and the control unit provided in the control center 21 will be explained based on the flowchart of FIG.

First, in step 101, when the vehicle is traveling, the vehicle-side wireless device 5 selects whether to perform polling communication or contention communication depending on the zone A or B in which the vehicle is located. Next, in step 102, it is determined whether the position beacon receiver 6 has received position data from the position beacon transmitter 15 located at the stop on the boundary line C between zone A and zone B. , when the position beacon receiver 6 receives the position data, proceed to step 1.
At 04, the zone in which the vehicle is located is determined based on the information from the route storage memory card 3 and the distance sensor 7. If it is determined that the vehicle is traveling in Zone A, the communication of the vehicle-side wireless device 5 is activated. In step 105, the communication of the vehicle-side wireless device 5 is switched to contention communication, and when it is determined that the vehicle is traveling in the B zone, the communication of the vehicle-side wireless device 5 is switched to polling communication in step 106.

In this way, the communication method can be switched between the polling method and the contention method according to zones with different communication volumes, so that the communication between the vehicle and the control center can be performed without sacrificing immediacy.
It is possible to reliably exchange data with 1.

If the communication method of the vehicle-side wireless device 5 is set to the contention method, data overlap is likely to occur, but in order to prevent this overlap, each control unit performs control according to the flowcharts shown in FIGS. 4 to 6. .

First, when the position beacon receiver 6.6 of each vehicle A, B receives position data from the beacon transmitter 15.15 (step 201.301), the data A, B is transmitted to the base station (step 202). .302), wait for a reply from the control center 21 for a certain period of time (step 203.303),
When the control center 21 receives data A and B (step 401), it is determined whether or not the data A and B overlap (step 402). As a result of the determination, if data A and B overlap, a try signal is transmitted to the wireless device 5.5 of each vehicle A and B (step 403). When the retry signal is received by the vehicle's wireless device 5.5, a random number is generated (step 204, 304), a timer is activated to randomly output (step 205, 305), and the timer is activated to output a random number at each set constant value (step 204, 304). When the time TASTB has elapsed (steps 206 and 306), the data A is
, B are transmitted from the wireless device 5.5 to the control center 21 (steps 20?, 30?), and when the wireless device of the control center 21 receives the retransmission data (step 40I), steps 402 and 403 are performed again. The process is repeated, and data A and B are each received when there is no overlap.

In this manner, when data overlaps during transmission using the contention method, the data is retransmitted from the vehicle-side wireless device 5 after a certain time difference, so that each data can be reliably received.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, when data overlaps during transmission using the contention method, it is determined whether the data overlap, and based on the determination result, a certain time difference is set. It will be retransmitted, so
Each data can be reliably received.

[Brief explanation of the drawing]

The drawings show an embodiment of the traffic control system according to the present invention, in which Fig. 1 is a block diagram showing the circuit configuration, Fig. 2 is a bus route map, and Fig. 3 is a flowchart showing the control operation of the vehicle-side control unit. 4 to 6 are flowcharts showing control operations of each control unit in the contention method. (Brief explanation of drawings showing main parts) 1. Vehicle side control system 2. Vehicle side control unit 3. Route storage memory card 4. Card reader 5. Vehicle side wireless device 6.
Position beacon receiver 7... Distance sensor 11... Stop side control system 12... Stop side control unit 13... Stop side wireless device 15... Position beacon transmitter 21... Control center

Claims (1)

[Claims] A traffic control system that performs contention-based communication between a base station and a plurality of vehicles, the system comprising means for determining overlapping data transmitted from wireless devices mounted on each vehicle; A traffic control system comprising: a retry means for causing each of the wireless devices to retransmit each data when the wireless device is present; and a means for setting a time difference between retransmissions of each data by the retry means. .