JPS5820175B2 - Polling communication method from fixed station to mobile station - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a polling type communication system from fixed stations distributed in a wide area diversity system to mobile stations.

Polling from a fixed station to multiple mobile stations
When transmitting and receiving data sequentially in the form of interrogations using the ing) method, conventionally, if a wireless communication line with poor transmission quality, such as an HF line, was used, the propagation characteristics would differ depending on the relative position of the mobile unit and the fixed station. Even if the station sends the question multiple times, it is difficult for all mobile units to respond, and there is a problem in that it is not possible to obtain optimal data.

In addition, repeatedly transmitting the same question data over and over again lowers the overall effective transmission speed, and in order to obtain optimal transmission quality for all mobile units, it is necessary to increase the operating frequency, etc. There were drawbacks such as extremely high costs.

The present invention has been made to eliminate the above-mentioned drawbacks of the conventional technology, and by implementing the present invention, it is possible to transmit data from a fixed base on land to a wide range at a relatively high speed using a wireless line with poor transmission quality such as an HF line. When trying to get a response to data sent to a moving aircraft or ship using a polling method, it is relatively easy to obtain high-quality data even over radio links whose propagation conditions change from moment to moment. A practical effect is expected.

Next, the present invention will be explained in detail by way of examples.

FIG. 1 is an example diagram of a communication system in which the present invention is implemented, with A, B,
C is a fixed station located in a wide area.

bl,...Xl are mobile stations.

The optimal station A, B, or C calls these plurality of mobile stations in order and transmits a message in the form of a question.

Responses from mobile stations are always received simultaneously by fixed stations A, B, and C, and are sent to central control station A (fixed station A) using high-quality dedicated lines such as wired lines or micro lines. the same) and obtain the optimal data using error correction or matching majority voting techniques.

In Figure 1, the double solid line is the dedicated circuit, the solid line is the HF wireless line from the fixed station to the mobile station, and the broken line is the HF line from the mobile station to the fixed station.
Indicates a wireless line.

In addition, the individual address of the mobile station when making a question must be determined in advance when configuring the communication system. The figure is a block diagram of an example circuit configuration of a processing device for received data of a central control station.
The figure shows each format of inquiry data from the fixed station to the mobile station using the polling method and the mobile station's response to it. Figure 6 is a flow chart of the process from the central control station collecting the data to outputting it. explain.

Now, normally the fixed station is the transmitting part (upper stage) of the transmitting/receiving device shown in Figure 2.
The interrogation data format shown in FIG. Respond with a response format like .

Note that A1 from a to b in FIG.
For example, if n=3, the code length is 2n-1).
1=7, and in the illustrated example, the binary code is 1011100.

In addition, Dl of b-c is question data for 31 stations, and 1
001100...101 is an example.

The SP of c-d is a termination signal, and this SP uses an M-sequence code common to all mobile stations, and is shown as 0101110 in the figure.

Now, to explain the above operation in more detail, first, the address (code) of the mobile station to be interrogated is set in advance in the control unit 5 of the fixed station transmitter/receiver shown in FIG. The modulator 6 is caused to output a binary code for calling the set mobile station.

The modulator 6 converts its input into a modulated signal for transmitting over an HF radio line, such as a frequency shift (FSX) or a phase shift (
PSK) signal and transmit it from the transmitter 7 and antenna AT as well.

In this case, starting and turning off the transmitter is controlled by a control signal from the control section 5.

Subsequently, question data that has been input into the memory section 2 via the interface section 1 from a fixed station terminal device, such as a keyboard or tape reader of a printing telegraph machine, and stored in advance, is converted into an error correction code by a control signal from the control section 5. The signal is sent to the adding section (Ept+) 4, where a parity code (for example, there is a BCH code) for correcting errors occurring in the middle of the wireless transmission line is added.

That is, a parity code p is added to each character of the information I, and the information is transmitted via the modulator 6, the transmitter 7, and the antenna AT.

When the output of the inquiry data from the memory unit 2 is completed, the address code transmitting unit 3 once again causes the mobile station to send out a termination signal indicating completion of data transmission, and transmits the data over the wireless line.

Next, in the mobile station, the digital code transmitted over the radio line is received by the receiving antenna AR1 receiver 14 and demodulator 15 of the transmitting/receiving device as shown in FIG. 3, and is demodulated and output as a digital code.

In each mobile station, a control signal specifying the address of the own station set in advance by the controller 17 is given to the comparator 16, so that the demodulated M-sequence code is the address of the own station and a certain number of bits (for example, 7 bits). If more than 5 pinto) match, the error correction unit (EpR2) 18 corrects the error in the subsequent received data one character at a time using information I and parity code p, and corrects the error that occurred in the wireless line. .

For example, mobile station a1 determines A1 in FIG. .

Note that the comparator 16 also detects the termination code SP, and as shown in FIG.
Immediately after detecting this at the dl position, the transmitting section for question and answering is operated through the control section 17.

In the transmitting section shown in the lower part of FIG.
The error correction code adding section (Ept2) 23 adds an error correction parity code p to each word of information I in response to a response control signal from the EPT2.

Prior to sending out this information, a start code ST (d2 to e in FIG. 5 2) composed of an M-sequence code is stored in the memory 22, for example, by a control signal from the control unit 17.
At the end of the response D2, the same end code SP as at the end of the question data is sent by the control signal of the control section 17.

In this way, the start code is the M sequence code common to all mobile stations, and the end code is the M sequence code common to all fixed stations and mobile stations.
Each series code is used.

Now, the modulating section 24 in FIG. 3 is a modulator for transmitting the digital signal from the Ept 223' as a modulated signal from the transmitter 25, and the transmission start of the transmitter 25 is started by the control signal of the control section 17 before sending out the response. will be carried out.

62-g in FIG. 52 is the format of this response.

When the comparator 16 detects the end code at d in FIG. 1, the transmitter is switched to the transmitting (on) state, and the start signal s' shown in d2 to e in FIG. 5 is transmitted after the rise time of the transmitter. r
, e to f and the parity code p, and the end signal sp of f-gl, when the transmission of SP is completed, the transmitter 25 is automatically cut off and turned off.

Next, the operation of the fixed station in response to the response signal will be explained.

The response signal from the mobile station is normally received simultaneously by all of the fixed stations A, B, and C, which are located in a wide area, by the receiving apparatus shown in FIG.

The digital codes received by each station are collected at a central control station via a dedicated line, and optimal response data is obtained by the central control unit shown in FIG.

To explain in detail, all fixed stations receive the signal using the receiving antenna AR and receiving section 8 shown in FIG. 2, and demodulate it into a digital signal using the demodulator 9.

This demodulated signal is put into the memory 12 for timing adjustment,
The signals are sent from the output section 13 to the central control station via a dedicated circuit at the same timing.

Note that the comparison section 10 and the error correction section 11 are operated by control signals from the control section 5 only when data processing is performed only at the fixed station without performing data processing at the central control station.

Therefore, normally the error correction section is bypassed as shown in FIG. 2, and the start signal, data (information ■ and parity code p), and stop signal shown in FIG. .

FIG. 4 is a block diagram of the received data processing device of the central control station. Mobile station response signals as shown in FIG. 32 respectively.

For example, the data received by station B is sent to the interface section 3.
1, and then input to the synchronization detection section 29 after time base adjustment in the memory section 27.

26 and 28 are also memory sections. The synchronization detection section 29 synchronizes the words (frames) of the three stations using a start signal composed of an M-sequence code.

That is, the words to be compared and verified for three stations using the same data are synchronized.

Then, the next error correction section 33 outputs the optimum data to the output section 34 according to the correction flow diagram shown in FIG.

I will now explain Figure 6.

The error correction unit 33 first determines whether there is an error in the information 11 from the A station and the parity code p1 in step (1) for each word, and if it is determined that there is no error, the error correction unit 33 Output.

If it is determined that there is an error, a similar determination is made in step (2) using the information ■2 from the B station and the parity code p2, and if there is no error, I2 is output, and if there is an error, (
In step 3), a similar determination is made using the information I3 from the C station and the parity code p3.

If there is no error, output I3. However, 1) (2) (
3) If it is determined that there is an error in any step, error correction is performed using information I and parity code p for each round, and a final output is obtained for each corresponding bit by a collation majority vote method.

For example, the data after error correction of each station A, B, and C is 101110.101010. If it is 001110, the result of bit matching majority vote will be 101110.

In this way, optimal data is sequentially obtained for the response data of the mobile station.

If a certain fixed station, for example station A, transmits interrogation data to a certain mobile station and response data is not returned even after a certain period of time has passed, the control signal from the transmission control unit 35 of the central control station shown in FIG. The transmitter of the fixed station, for example, station B, is operated to transmit the same question data.

That is, as shown in FIGS. 3 and 4, the address code Am,
If response data is not received even after t3 hours have elapsed after transmitting the inquiry data Dn and data end code SP, Am, Dn, and SP are transmitted again from another fixed station.

ST, Dn+1, and SP in FIG. 5 are examples of responses to this second question.

Further, if there is no response even after transmitting the question data a predetermined number of times, the next question data is transmitted to the next mobile station.

Am+1 and Dm+2SP in FIG. 3 indicate the address code, interrogation data, and data end code for that station, respectively.

As explained above, fixed stations placed in a wide area taking into account various conditions transmit question data sequentially to mobile stations as appropriate using the polling method, and the response data received simultaneously by multiple fixed stations is sent to the central station. If the station equipment detects error-free data or obtains optimal data by collating data from a plurality of stations, high-quality data can be received, so it has a wide range of practical applications as described above.

[Brief explanation of drawings]

FIG. 1 is an example of a communication system in which the present invention is implemented, FIGS. 2 and 3 are circuit configurations of fixed station and mobile station transmitting/receiving devices, respectively, and FIG. 4 is a configuration of a central controller. Fifth
The figure shows the question and response message format, and FIG. 6 is a flowchart of the process from the central control station collecting data to outputting it. 1.21, 30, 31, 32... Input interface circuit, 2, 12, 19, 22, 26° 27.2
8...Memory, 3...Address code transmitter, 4.23...Error correction code addition unit (Ept)
, 5゜17... Control section (CONT), 6, 24
...Modulation section, 7.25 ...Transmission section, 8
, 14...Receiving unit, 9°15...Demodulator, 10,16...Comparing unit, 11°18, 3
3...Error correction unit (E pR), 13, 20
゜34...Output interface circuit (output section), 29...Synchronization detection section, 35...1 transmission control section.

Claims (1)

[Claims] 1 In a communication system in which a fixed station and multiple mobile stations moving within a wide area exchange digital codes by radio transmission, the fixed station sends inquiry data to multiple mobile stations in a predetermined format and each mobile station When collecting response data sequentially from a network, multiple fixed stations are distributed within the area, and the transmission and reception of each fixed station is controlled within one of the stations or at an appropriate location using a dedicated line with good transmission quality. In addition, a central control unit is provided for processing transmitted and received data, and the plurality of fixed stations simultaneously receive response data from a designated mobile station in response to question data with a specified address transmitted from one fixed station under the control of the central control unit. This data is collected in a central control unit, error corrected or collated, and the optimal data is output, and questions are sequentially asked to other mobile stations using the same procedure. A fixed station system characterized by transmitting the same interrogation data from other fixed stations in order within a certain period of time until a response is obtained when the interrogation data cannot be obtained from any fixed station, and then sending the interrogation data to the next mobile station. A polling communication method from the station to the mobile station.