JPS60254941A - Data communication method with variable transmission speed - Google Patents

Abstract

PURPOSE:To shorten a communication time by giving a slow signal transmission speed (baud rate) to a distant slave station and improving the data reception efficiency of a master station, and giving a fast transmission speed (baut rate) to a nearby slave station. CONSTITUTION:The transmission rate of signals are set to 1,200 baud when position group signals is received from sign posts a1 and a2 corresponding to areas A1 and A2, to 600 baud when signals are received from sign posts b1, b2, b3, and b4, and to 300 baud when signals are received from sign posts c1, c2...c8. Consequently, a polling signal is received by the radio equipment 23 of each slave station 2 and the area C6 is specified with the polling signal; when a slave station 2 positioned in the area C6 is addressed, a position group signal is sent to a signal processor 21 through an area signal generating circuit 32 and a timer for signal transmission is switched to set the transmission rate of signal sent to the master station 1 to 300 baud.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a mutual data communication method between one station, for example, a master station, and another station, for example, a plurality of slave stations. When polling from the master station, the transmission speed (baud rate) of the response signal from the slave station to the master station is changed according to the current area of the slave station, and the response signal from the slave station is sent to the master station. This aims to improve the data reception rate and shorten the communication time with slave stations.

゛ [Prior Art] Conventionally, for example, in the AVM (Automatic Vehicle Location Display) system of taxi radio, when mutual data communication is carried out between a master station, which is a base station, and a plurality of slave stations, which are mobile stations. , the mutual signal transmission speed (baud rate) was kept constant.

[Problems to be Solved by the Invention] In the conventional method described above, when a slave station returns a response signal based on a polling signal from a master station, the master station is unable to send back a response signal to a remote station. A situation has arisen in which a response signal from a station cannot be reliably received.

[Means for Solving the Problems] However, in the present invention, the slave station receives position group signals from signposts installed in each district, and when polling from the master station, the slave station receives position group signals based on the position group signals. This method involves changing the signal transmission speed (baud rate) of the slave station. In other words, a slow signal transmission rate (baud rate) is given to slave stations located far away to improve the data reception rate at the master station, while a fast transmission rate (baud rate) is given to slave stations located close to each other. rate) to reduce communication time.

[Embodiment] An embodiment of the data communication method according to the present invention will be described below with reference to the drawings.

First, an example of a communication area as shown in FIG. 1 will be described. (1) is a master station with a transmission output of 25 W, and (2) is a plurality of slave stations with a transmission output of 5 W. master station(
1), the area within a radius of 5 km where the slave station (2) moves will be set as area A, and the area beyond that will be 10 km.
The range within m is set as area B, and further beyond that is set as area B.
The range within Km is set as area C. Also, for convenience, area A is divided into two areas as districts A1 and A2, area B is divided into four areas as areas B1, B2, B3, B4, and area C is divided into eight areas as areas CI, C2, etc. ...It is set as C8. Furthermore, each of these districts A1, A2, B1, B2, B3
, B4, C1, C2, ...... C8 are sign posts a of small transmitters that transmit position group signals specific to each district.
1, A2, bl, B2, B3, B4゜cl, C2,・
...Install each C8.

Next, FIG. 2 is a block diagram of the master station (1), and FIG. 3 is a block diagram of the slave station (2).

In FIG. 2, the master station (1) includes a signal processing device (11) consisting of a microcomputer, etc.
1) constant transmission rate V from. , a modulation circuit (12) for modulating a polling signal having, for example, 300 baud, and a modulation circuit (12) for outputting the modulated output from this modulation circuit (12) as radio waves, and for receiving radio waves from the slave station (2). a radio device (13); and a first radio device for demodulating the received output from the radio device (13) that has received radio waves from the slave station (2).
A first demodulation circuit (14t) suitable for a transmission rate V, (300 baud), a second demodulation circuit (14t) suitable for a transmission rate v2 (600 baud)
A second demodulation circuit (142) suitable for the third transmission speed V
A third demodulation circuit (14
a),...Nth demodulation port 1111 (14n) suitable for the Nth transmission rate Vn and these demodulation circuits (14n)
t).

(142), (14a), ...... (14n), and each demodulation circuit (14t), (142), (14
Determination circuits (151) and (1) for determining whether or not the demodulated signals from a), ...-(14n) are normal and outputting only the normal demodulated signals to the signal processing device (11).
52), (15a), -=-(15n) and an input device (1) such as a keyboard connected to the signal processing device (11).
7), an output device (18) such as a cathode ray tube, and an external storage device (19).

On the other hand, in FIG. 3, each slave station (2) receives radio waves from the master station (1) and also includes a radio device (23) and a radio device (23) for outputting radio waves to the master station (1). ) from a constant transmission rate V. , for example, a demodulation circuit (22) suitable for demodulating the received output of 300 baud, and a demodulation circuit (22) that processes the demodulation output from the demodulation circuit (22), while mainly processing the transmission signal to the master station (1). Signal processing bag [1 (21) consisting of a microcomputer, etc., and this signal processing device (21)]
a first transmission rate V, (30
a first modulation circuit (24, ) suitable for a transmission rate V (0 baud), a second modulation circuit (24t) suitable for a transmission rate V 3 (600 baud), a third modulation circuit (24, ) suitable for a transmission rate V 3 (1200 baud); A third modulation circuit (24a) suitable for...
Nth modulation circuit (24n) suitable for Nth transmission speed Vn
This signal processing device based on the modulation circuit switching output from the signal processing device (21)! Modulation circuits (241), (24t), (24s), etc. from (21)
... a first modulation circuit switching means (25) for switching the input signal to (24n), and the signal processing device (21)
Based on the modulation circuit switching output from the modulation circuit (241
), (242), (243), ...... (24n)
A second modulation circuit switching means (26) for switching and connecting the modulated output from the radio device (23), and dynamic data such as empty cars, actual cars, and forwarding to the signal processing device (21). For example, a taxi meter device (
27), a car number signal generation circuit (28) which similarly inputs a unique number unique to each slave station (2), that is, a car number signal, to the signal processing device (21), and District A shown
1, A2, B1, B2. B3, B4, C1, C2,...
...Sign post a1, B2 installed for each C8,
A signpost receiver (30) that receives location group signals from bl, B2, B3, B4, cl, C2-...=c8, and a district corresponding to the location group signal received by the signpost receiver (30). Data and signal transmission rate (baud)
and a district signal generation circuit (32) for specifying the rate.

In addition, sign post al corresponding to areas A1 and A2.

When receiving the position group signal from B2, set the signal transmission rate to 1200 baud, and similarly
1, B2. When receiving signals from B3 and B4, set the signal transmission rate to 600 baud, and send the signal to signposts C1 and C2.
...When receiving from C8, 300 baud is set as the signal transmission rate.

In such a configuration, when the master station (1) collects dynamic data of each slave station (2), the input device (17) is operated to generate a polling signal in the signal processing device (11) of the master station (1). to occur. Then, this polling signal is sent to each slave station (
2) is output. When such a polling signal is received by the radio device (23) of each slave station (2).

After the received output is demodulated in the demodulation circuit (22), it is sent to the signal processing bag! ! (21) is input. Here, if the polling signal specifies district C6 and there is a slave station (2) located in district C6, then the sign post (C
The position group signal from 6) is received by the sign post receiver (30). Then, this position group signal is sent to the signal processing device (21) via the district signal generation circuit (32), and the signal transmission timer is switched to adjust the transmission speed of the signal transmitted to the master station (1). is 300 baud. Further, the first and second modulation circuit switching means (25) and (26) switch the first modulation circuit (241) according to the modulation circuit switching output from the signal processing device (21) as shown in FIG. Since the signal is selected, the signal is sent to the first modulation circuit (24□) and the radio device (
23) to the master station (1).

In addition, the sign post receiver (30) is a sign post receiver (30).
Even if the signal from C6) cannot be received, the signal from that sign post (C6) is stored as is for a certain period of time unless a signal from another sign post is input. In other words, even within the set area, reception is temporarily interrupted due to buildings, etc., or when moving from one area to another, it is possible to prevent the occurrence of areas where position group signals cannot be input.

Here, an example of a signal transmitted from the slave station (2) to the master station (1) is shown in FIG. The transmitted signal consists of a prefix bit synchronization signal, a frame synchronization signal, dynamic data such as "empty car, actual car, forwarding, etc.," district data, car number data, and a correction signal.Signal processing device (21) , an empty car,
Signals for dynamic codes such as actual vehicle and forwarding are input from the taxi meter device (27), and vehicle number data is input from the vehicle number signal generation circuit (28).

The district data from the sign post is sent to the district signal generation circuit (3
2).

The radio waves transmitted from the slave station (2) are transmitted to the master station (1)'s radio (
13) and each demodulation circuit (14*), (14
2), (143), . . . via each judgment circuit (15t), (152), (15a), .
...(15n) will be input. Each judgment circuit (15t), (15sr), (153),...
・In (15n), each demodulation circuit (14t), (142),
(14a), . . . (14n), and determines the optimal demodulated signal among the demodulated outputs from (14n).
15t) will output the demodulated signal to the signal processing device (11), so the signal processing device (11) should directly display the car number and dynamics of the slave station (2) on the output device (18). , or stored in a storage circuit within the signal processing device (11) or an external storage device (19). By the way, the transmission speed of the signal from slave station (2) is 300 baud.
Even if it is different from 600 baud or 1200 baud, 1 judgment circuit (15t), (152), (15a), etc.
(15n) is compatible with each baud rate and determines whether the prefix bit synchronization signal or frame synchronization signal in the signal from slave station (2) is normal.
Only the demodulated signal determined to be normal is processed by the signal processing device (11)
will be output for.

In addition, each subsidiary station (
Regarding 2), when there is polling from the master station (1), the timer for signal transmission in the signal processing device (21) is switched based on the position group signal from each corresponding sign post, and the timer for signal transmission is switched to a predetermined time. The signal transmission speed of the first and second modulation circuit switching means (25) and (26) is designated by the modulation circuit switching output from the signal processing device (21).
) selects a predetermined modulation circuit (24,) to (24n), so that the signal containing the car number data, district data, and dynamic data of the slave station (2) is transmitted to the radio device (23) at a predetermined transmission speed. The data will be transmitted to the master station (1) via the host station (1).

[Effects of the Invention] As described above, in the present invention, when a polling signal is transmitted from the master station (1), the slave stations (2) in the area respond at a predetermined response transmission rate based on the position group signal received from the sign post. will be changed to In other words, the slave station (2) located close to the master station (1) is set to a fast signal transmission speed, and the slave station (2) located far from the master station (1) is set to a slow signal transmission speed. Set. Therefore, in the case of a slave station (2) located far away, the master station (1) can reliably receive and process the signal since the signal transmission speed is slow, and in the case of a slave station (2) located at a short distance, Since the signal transmission speed is high, the time required to transmit the signal can be significantly shortened. Moreover, since the signal transmission speed is determined by the position group signal from the signpost without being specified by the master station (1), the polling signal becomes simple.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an example of a communication area according to the present invention, FIG. 2 is a block diagram showing a master station, FIG. 3 is a block diagram showing a slave station, and FIG. FIG. 2 is a diagram showing the configuration of a signal. In the figure, (1)...master station, (2)...slave station, (11)
, (21)...signal processing device, (12), (24□
), (242), (243), ~(24n)...Modulation circuit, (13), (23)...Radio device, (14t),
C1,,42), (14a), ~(14n), (22)
... Demodulation circuit, (151), (152), (153)
, ~(15n)...determination circuit, (17)...input device, (18)...output device, (19)...external storage device, (25), (26)...switching Means, (27)・
... Taxi meter device, (28) ... Vehicle number signal generation circuit, (30) ... Sign post receiver, (32) ...
...District signal generation circuit. Applicant General Co., Ltd. Figure 1 Figure 4

Claims (1)

[Scope of Claims] (1) In a method for mutual data communication between one station and another station based on an instruction signal from one station, the other station posts sign posts for each district. When one station sends an instruction signal to the other station, the signal is transmitted from the other station to the other station based on the position group signal received at the other station. A data communication method with variable transmission speed, characterized in that the speed is changed. (2. In claim (1), one station is a master station, and the other station is a plurality of slave stations. A data communication method with variable transmission speed. (3) Patent In claim (1) or (2), the instruction signal from one station to the other station is a polling signal, and the signal from the other station to one station is a response signal based on the polling signal. (4) In claim (1), (2) or (3), one station located far from the other station transmits a slow signal A data communication method with variable transmission speed, characterized in that a transmission speed is assigned.