JPS6121632A - Monitor equipment of operating state of vehicle - Google Patents

Abstract

PURPOSE:To prevent re-collision at transmission restart after release of inhibition by inhibiting automatically transmission from other mobile station when one mobile station makes transmission earlier to prevent collision of data due to simultaneous transmission and to make transmission inhibition time different from mobile stations. CONSTITUTION:When data of a talking signal is transmitted from a mobile station 2 to a base station 1, since a detection section 28 or 29 of the own station detects a talking request from an optional call request, a control section 24 discriminates the presence of a reception signal addressed to the base station 1 from other mobile stations 2', 2'' from an output DET of a detection section 23. When absent, the transmission of requested data or a talking signal is permitted, but when the reception signal exists, the talking is inhibited for Tsec or the transmission of data is awaited. The transmission waiting of the data signal is executed automatically by the control section 24, while the inhibition of talking is informed to a caller for the ineffective talking through the issue of buzzer alarm. A transmission inhibition time generating section 25 provides a table such as a random number table and generates a time T different from each mobile station.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a device for monitoring the operating status of a vehicle through a wireless line, and in particular, to prevent data from colliding with each other from multiple vehicles.

[Conventional technology]

In order to understand the operating status of multiple vehicles in transportation operations, etc., each vehicle is used as a mobile station to transmit data indicating the operating status, and this is received by a common base station to automatically generate daily business reports for each vehicle. It is often created. Such an AVM system uses an arbitrary calling method to send data from the vehicle side to the base station when a change in operating conditions occurs.

[Problem that the invention seeks to solve]

However, in the arbitrary calling method, data is sent unilaterally without considering the status of the base station or the status of other mobile stations, so in an AVM system that shares the same frequency radio line, it is difficult for other mobile stations to There is a possibility of collision with the data and call signals sent to the base station.

For this reason, when the base station successfully receives a response signal, it sends a response signal back to the corresponding mobile station, but the data that collides with the data is destroyed, so procedures such as retransmission must be taken, which can be time consuming and time consuming. There is a drawback that it takes

Means for Solving Problem C] The present invention checks the usage status of the wireless line and stops transmission from its own station when it is already in use to avoid collisions of data, etc. It is something. For this reason, the present invention provides an apparatus in which a plurality of vehicles are used as mobile stations, and the operating status of each vehicle is monitored on the base station side by connecting the mobile stations to a common base station using wireless lines of the same frequency. a received signal detection unit on the mobile station side that detects that another mobile station is transmitting;
The mobile station comprises a transmission signal control section that temporarily prohibits transmission of its own station in response to the output of the detection section, and a transmission prohibition time generation section that sets the transmission prohibition time differently for each mobile station. It is characterized by this.

[Effect]

When a request to transmit a call signal or data occurs at the local station, the usage status of the wireless line at that time is checked, and if the wireless line is already in use, the transmission from the local station is postponed to prevent collisions. At this time, if the transmission postponement time (prohibited time) is randomly set for each mobile station, the probability of re-collision will be significantly reduced because the restart time will be different for each mobile station.

〔Example〕

Hereinafter, the present invention will be described in detail with reference to the drawings.

Figure 1 is a schematic diagram of the AVM system, where 1 is a base station, 2 -
2'' is a plurality of mobile stations (vehicles) that share the same frequency radio line. Fig. 2 is a block diagram showing the configuration of mobile station 2 (others are the same), 21 is an antenna, and 22 is a transmission function. 23 is a received signal detection unit; 24 is a transmission signal control unit that receives the detection signal I) ET from the detection unit and controls whether or not to transmit; 25 is a transmission signal control unit that controls transmission time T that is prohibited by the control unit 24; Random transmission prohibition time generation section that is given differently for each mobile station, 26 is a key power section used when transmitting data, 27 is a microphone used when transmitting voice signals, 28 is an arbitrary call origination by operation of the key power section 26 Request detection unit, 29
1 is a detection unit for detecting a call request using a breath talk switch (not shown) of the microphone 27.

FIG. 3 is a flowchart showing the operation of the transmission signal control section 24. The overall operation will be explained below with reference to this figure. When attempting to transmit data or a call signal from the mobile station 2 in FIG. 1 to the base station 1, the detection unit 28 in FIG.
Or 29 detects an arbitrary call request or a call request, so
At that time, the control section 24 outputs the output DET of the received signal detection section 23.
It is determined whether there is a received signal from other mobile stations 2', 2'', etc. (originally addressed to base station l). If there is no received signal, the transmission of the requested data or call signal is permitted, but If there is, telephone calls are prohibited for T seconds, or data transmission is put on standby.The data signal transmission standby can be automatically performed by the control unit 24, but the prohibition of telephone calls must be notified by a buzzer or the like.

In other words, if a reception signal from another mobile station is detected when a call request occurs, not only will the input from the microphone 27 not be transmitted for T seconds after that, but the call will be invalidated by sounding a buzzer, etc. Inform the speaker.

The transmission prohibited time generating section 25 includes a table such as a random number table, and generates a different time T for each mobile station. Therefore, when mobile stations 2 and 2' start transmitting at approximately the same time, there is a possibility that they each receive the other party's signals and go into a standby state. ) are different from each other, so the shorter one can be transmitted first, preventing re-collision.

〔Effect of the invention〕

As described above, according to the present invention, in a device in which a plurality of mobile stations share a radio line with the same frequency and transmit data indicating the operating status to a common base station, one mobile station transmits data first. Since transmissions from other mobile stations are automatically prohibited when the mobile station is
can be prevented.

Furthermore, since the transmission prohibition time differs for each mobile station, re-collision can be prevented when transmission is resumed after the prohibition is canceled.

[Brief explanation of the drawing]

FIG. 1 is a schematic block diagram of an AVM system, and FIGS. 2 and 3 are block diagrams and flow charts showing one embodiment of the present invention. In the figure, l is a base station, 2.2', 2'' are mobile stations, 21 is an antenna, 22 is a radio, 23 is a received signal detection unit, 24
3 is a transmission signal control unit, 25 is a transmission prohibition time generation unit, 26 is a key input unit, and 27 is a microphone.

Claims (1)

[Claims] In a device that connects multiple vehicles as mobile stations to a common base station via wireless lines with the same frequency and monitors the operating status of each vehicle on the base station side, each mobile station has a a received signal detection unit that detects that the mobile station is transmitting, a transmission signal control unit that temporarily prohibits transmission of the own station in response to the output of the detection unit, and a transmission signal control unit that temporarily prohibits transmission of the mobile station; 1. A vehicle operating status monitoring device comprising: a transmission prohibition time generating section that is set differently for each station.