JPH02228853A - Transmission control system for data communication and its modem equipment - Google Patents

Abstract

PURPOSE:To attain highly efficient and highly stable data communication by applying a 1st transmission control protocol and a signal of a 1st transmission frame form between a data device and a MODEM and applying a 2nd transmission control protocol and a signal of a 2nd transmission frame form between MODEMs. CONSTITUTION:A 1st transmission control protocol (BSC protocol or HDC protocol or the like) and a signal of a 1st transmission frame form (transmission frame form for BSC protocol or HDC protocol or the like) are adopted between data equipments 1, 2 and MODEMs 3, 4, and a 2nd transmission control protocol and a signal of a 2nd transmission frame form able to secure the data reliability are applied to a line whose line error rate is 10<-3> and having much burst error between the MODEMs 3 and 4. The ARQ (automatic repeat request) system based on the FEC(forward error collection) system is adopted for the signal error control. Thus, the retrial due to frequent occurrence of the data error and the retrial due to timeout caused by no reply are reduced and the stable data communication with excellent transmission efficiency is attained.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a transmission control method and modem device for data communication in a communication system including a wireless transmission path such as a public mobile phone.

(Prior art) Transmission control procedures in conventional data communications are described in "Norotocol Handbook" (1986-4-15) Asahi Shimbun P.89
-177.

FIG. 8 shows an example of the configuration of a conventional data communication system.

In Figure 8, No. 5 is a general-purpose host computer (HO8
T>, 52 is data terminal equipment (DTE), 53 and 5
4 is a modem (MODEM), and 55 is a dedicated telephone line.

MODEM 53 and MOD connected to dedicated communication line 55
The data link level transmission control procedure used for data communication between the HO8T 51 and the DTE 52 via the EM 54 is the basic data transmission control procedure described in the protocol and handbook, and the BSC (binary synchronous
Communications: B 1narySynchr
onous Communications) Procedures, H
DLC (High Level Data Re/Recontrol Control Procedures) High Level Data Lin
k Control Procedure) Procedure, 5D
LC (Synchronous Data Link Controller) o-ru: 5synchronous Data Link C
ontrol) procedures are commonly used.

FIG. 9 shows an example of the first BSC procedure using the conventional 71J programming/selecting method when there is no data error, and FIG. 10 shows the second BSC procedure using the conventional polling/selecting method when there is a data error. This is an example of the procedure.

The format of the transmission frame used for data transmission in the BSC procedure, )[)LC procedure is described in the aforementioned "'j' Protocol Handbook," but some of it is shown in Figures 11, 12, and 1.
This is shown in Figures 3 and 14.

The first of the conventional 2-ring/selecting method shown in FIG.
The following describes the BSC procedure.

In the first step) IO8T 51 is DTE 52
Polling (POLL) to establish a data link to
In the second step, DTE 52 sends HO8T
Since there is no message to be sent to 51, a negative response EOT indicating the end of transmission or denial is returned.

In the third step, HO8T 51 sends POLL again to DTE 52, and in the fourth step, HO8T 51 sends POLL again to DTE 52.
Since the message to be sent to 51 is ready, the message is sent.

In the fifth step, the HOST 51 performs an error check on the BCC code for error detection in the received message, and sends an acknowledgment ACKφ indicating that the message has been received without error.

If there is an error in the message received in the fifth step, a negative acknowledgment NAK is returned to the DTE 52 to prompt retransmission of the message.

In the sixth step, the DTE 52 sends an EOT since there is no message to send to the HOST 51.

At the 7th station, the HOST 57 is ready to send the message to the DTE 52, and the DTE 52
Selecting (SEL) to establish a data ring with
), and in the eighth step, the DTE 52 returns and sends ACKφ, which means reception is possible.

In the 9th step, the E(O8T 51 sends a message to the DTE 52, and in the 10th step, the DTE 5
ACKl indicating that 2 received the message without error.
to be sent back.

Note that ACKφ is an acknowledgment for an odd-numbered message, and ACK 1 is an acknowledgment for an even-numbered message.

In the 11th step, the HOST 51 sends an EOT indicating that there is no message to send to the DTE 52, in the 12th step, the HOST 5J sends a POLL to the DTE 52 as in the 1st step, and in the 13th step The DTE 52 returns an EOT to HOST s 1 to terminate the transmission, and the BSC procedure ends.

Next, the main points of the BSC procedure shown in FIG. 10 will be explained.

The first step indicates that there was an error in the POLL sent from HO8T51 to DTE 52 to establish a data link.

In this case, since the DTE 52 could not interpret it as POLL, it is not responding to the HOST 51.

In the second step, since there is no response from DTE 52, HOST s J sends POLL to DTE 52 again due to the timeout of HOST s 1's own timer.

In the third step, the DTE 52 returns an EOT to the HOST 51 in response to the received POLL, indicating that there was an error in the EOT.

In the fourth step, the DTE 52 receives no response from the HOST 51, so the DTE 52's own timer times out! 0 Send EOT to HOST 51 again.

The sixth step indicates that message 1 sent from DTE 52 to HOST 51 is in error.

In the seventh step, since message 1 from DTE 52 contained an error, HOST 51 returns a NAK to DTE 52 requesting retransmission.

Basic data transmission control procedure other than Naori SC procedure, HD
The LC procedure, 5DLC procedure, etc. are explained in the aforementioned "Protocol Handbook".

The specifications of modem equipment used in data communication systems such as those mentioned above are explained in CCITT Red Book, Volume 4-1, Data Communication V Series Recommendations in Telephone Networks, April 22, 1986, Foundation, Japan ITU Association. has been done.

(Problems to be Solved by the Invention) The transmission frame format of the conventional data communication transmission control procedure is applicable to a dedicated communication line or the like with a data error rate of 10 or more.

However, some car phone systems, such as some commercial wireless systems, suffer from the fading phenomenon peculiar to mobile radio that occurs on wireless transmission paths, and systems that are subject to urban noise have a data error rate of 10-2 to 10''4. Bad: There is a problem in that it is difficult to apply conventional transmission control means and transmission frames.

More specifically, if the conventional BSC procedure and the transmission frame for the BSC procedure are applied to a car telephone system or some business wireless systems as shown in Figure 7, data errors will occur frequently and the procedure will have to be retried or the other party will There is a problem in that data transfer takes time because there are many retries of procedures due to timeouts due to no response.

The object of the present invention is to provide a transmission control system and a modem device used in the system to improve the above problems.

(Means for Solving the Problems) In order to achieve the above object, a primary station data device connected to a primary station modem device via a primary station and a secondary station modem device connected to a line; In a transmission control method for mutual data communication between secondary station data devices connected to a next station modem device, (e) the primary station or secondary station modem device is connected to the primary station or secondary station modem device; Means for issuing pseudo-commands and responding on behalf of the other data device, which is the communication partner of the data device connected to the device and forming one station.

(b) A first transmission controller J@ (BSC procedure, HDLC procedure, etc.) and a first transmission frame format are used between data devices connected to the primary station or secondary station modem device and forming one station. (Transmission frame format for BSC, HDLC, etc.) A means of commanding and responding using signals.

(c) a second transmission control means and a second transmission control means for commanding and responding to a partner station modem device of the primary station or secondary station modem device by sending a signal in the first transmission frame format to the first transmission control means; Means for exchanging signals in the transmission frame format of 2.

(a) The second transmission control procedure and the second transmission frame format signal from the partner station modem device of the primary station or secondary station modem device are transmitted to the own station modem device of the primary station or secondary station. Means for converting into a first transmission control procedure and a first transmission frame format signal for command/response with a data device connected to constitute one station.

(e) Between the modem equipment of the primary station and the secondary station,
means for commanding and responding using a transmission control procedure and a signal in a second transmission frame format.

A modem equipped with the means (a) to (e) above is described above.
The first transmission control procedure is applied to the next station and the secondary station modem device, and the first transmission control procedure is applied to the data transmission and reception between the primary station modem device and the primary station data device and between the secondary station modem device and the secondary station data device. The signal is in the first transmission frame format, and the second transmission control procedure and the signal in the second transmission frame format are used for data transmission and reception between the primary station modem device and the secondary station modem device, resulting in efficient data transmission. This is a transmission control method that made communication possible.

Furthermore, it is a modem device that achieves the above objectives (e) input/output for transmitting and receiving data with the data device side, output corresponding to data input of the modulation section of the analog telephone line modem, and demodulation of the analog telephone line modem. input/output means having an input corresponding to the data output of the section;

(b) a control means that handles input and output of the data dose using a first transmission control procedure and a first transmission frame format signal; (c) a modulation/demodulation section of the analog telephone line modem; (a) control means corresponding to input/output corresponding to the data side using a second transmission control procedure and a signal in a second transmission frame format; converting means for converting the signal into a signal in a second transmission frame format and sending the signal to an output corresponding to the data input of the modulation section of the analog telephone line modem; (e) a data output of the analog telephone line demodulation section; The Harburger-encoded data part of the second transmission frame format signal input from the analog line modem is decoded, and the error detection code in the decoded signal is checked. If there is an error, the analog line modem It outputs a negative response requesting retransmission to the output corresponding to the data input of the modulator of the modulator, and outputs an acknowledge response if there is no error, and transmits the decoded signal of the Kelberger code to the output of the first transmission frame format. 1. A modem device comprising: conversion control means for converting the signal into a signal and outputting the signal to a data device side; and the modem device is characterized in that it enables data communication with high transmission efficiency even on a line with many burst errors.

(Function) As mentioned earlier, conventionally the first transmission control procedure (BSC
procedures, HDLC procedures, etc.) and the first transmission frame format (B
Since a signal in a transmission frame format (for SC procedure, HDLC procedure, etc.) is adopted, the number of times data is transmitted and received between data devices increases, and the data transmission time increases.

However, according to the configuration of the present invention, for lines with a line error rate of 10-5 between modems and many burst errors,
applying a second transmission control procedure that can ensure data reliability and a second transmission frame format signal;
FEC (Forward Error Correction) is used to control errors in signals in the transmission frame format.
or Correction) method as a pace A
RQ (Automatic repeat request: A
automatic Repeat Request)
By adopting this method, it works to enable highly efficient and highly stable data communication.

(Embodiment) Before describing the embodiment, a first transmission control procedure and a signal in the first transmission frame format, and a second transmission control procedure and a signal in the second transmission frame format used in the present invention will be described.

The above transmission control procedure and its transmission frame format are being standardized by ISO (International Standardization Function).
8I (Open Systems Interconnection:
0pen Systems Interconst
This is the second layer (data link layer) of the seven layers of the ion (open system interconnection) reference model.

The first transmission control procedure and the first transmission frame format signal are the basic data transmission control procedure described in the above-mentioned "Grotocol Handbook" and the transmission frame format signal used in that procedure, and the BSC procedure and the transmission frame format signal used in that procedure. A signal in a transmission frame format (a part of the transmission frame format used is shown in Figures 11 and 12), an HDLC procedure and a transmission frame format used in that procedure (a part of the transmission frame format used is shown in Figure 13) 5DLC procedure and four types of transmission frame formats used in the procedure.

There are two types of second transmission frame format signals for the second transmission control procedure: data frame format signals and control frame format signals. The data frame format signal is used for data transmission and reception, and as shown in Figure 5, the FEC method is resistant to burst errors, and the Hague 9 Luberger code, which has the ability to detect errors and self-correct for a certain number of bit errors, is used. I'm hiring. The control frame format signal is a signal that inspects the data sent from the transmitting side and responds to the transmitting side.As shown in Figure 6, if there is no error in the data, an acknowledgment (ACK) is sent. There are two types of negative acknowledgments (NAKs) if there are any.

The second transmission control procedure is that when the receiving side receives the data frame format signal for information transfer from the transmitting side, the receiving side checks the data for errors, and if there is no error, it sends the acknowledgment (ACK). ), and if there is an error, the basic method is to respond with the aforementioned negative acknowledgment (NAK) requesting retransmission of the data.

The basics of encoding and decoding the Verdal-Gugar code are explained in "Data Communication" (July 10, 1971), Sanpo Co., Ltd., Iwao Yamamoto, pp. 127-130. .

FIG. 7 is a block diagram of the data communication system of a public mobile phone, in which 1 is a general-purpose host computer (HO8T
), 2 is the data terminal equipment (DTE), 3 is the land modem (LAND-MODEM) on the land side, and 4 is the mobile modem on the mobile station side (MOBI IJ-MODEM).
), 5 is a car phone device that provides car phone service, 6 is a wireless transmission path, and 7 is a station opposite the car phone device (mobile station), which is a wireless line control station for transmitting and receiving various signals in the wireless section and the car phone device. 8 is a wireless base station that performs signal relay between stations and monitors wireless line quality; 8 is a mobile telephone switching center that performs various functions such as connection with a general telephone switching network, mobile network switching connection, and billing control; 9 is a plurality of wireless base stations; 10 is a general telephone switching network.

When accessing the database of HO8T 1 from DTE 2 in the car via the data communication system of this public car telephone, the data is transferred to MOBILE-MODEM.
After being modulated by 4 and converted to voice band data,
The signal is high-frequency modulated by the car telephone device 5 and transmitted to the wireless base station 7. The voice band data demodulated by the wireless base station 7 is sent to the LAN via the mobile telephone exchange 8 and the general telephone exchange network 10.
Input to D-MODEM 3. LAND・MODEM
The data demodulated in step 3 is sent to HO8T 1.

Further, the data returned from HO8T 1 to DTE 2 is transferred in the opposite direction to DTE 2 in the car through the same line.

The modem device described in the embodiment performs first transmission control on behalf of the data device (data terminal device, general-purpose host converter, etc.) that is the communication partner of the data device (data terminal device, general-purpose host converter, etc.) connected to the modem device and forming one station. Child 1 [(BSC procedure, HD
LC procedure, etc.) and the first transmission frame format (BSC procedure,
It has the function of pseudo-command/response in HDLC (transmission frame format, etc.).

There is a data error using the signal in the second transmission frame format shown in FIGS. 5 and 6 and the signal in the BSC procedure transmission frame format (first transmission frame format) shown in FIGS. 11 and 12. The first transmission control procedure of the present invention (B
The transmission control procedure of the first embodiment of the present invention using the SC procedure) and the second transmission control procedure will be explained with reference to FIG.

As mentioned above (HO8T 1 and LAND-MODEM 3
Q and B between DTE 2 and MOBILE-MOD Ran 4
SC hand condyle procedure Responds with a signal in the transmission frame format of the SC procedure, LAND-MODEM3 and MOBILE-
While the wireless transmission path 6 of MODEM 4 is included, a response is made using the second transmission control procedure and a signal in the second transmission frame format.

Before entering the data link level transmission control procedure shown in Figure 1, call the other party from a telephone on either the HO8T 7 side or the D'rE Z side, create a telephone line, and then use this telephone line to 7 Create a data communication route with the configuration shown in Figure 7, and connect HO8T 7 and LAND/MODEM 3.
o between question and DTE 2 and MOBILE-MOD decoy 4.
The transmission control procedure at the physical level of the first layer of sr is performed, and the state is connected at the physical level.

Also, after the data link level transmission control procedure is completed, the first
Although not shown in the diagram, at the physical level HO8T 1 and L
AND-MODEM 3 and DTE2 and MOBILE・
MODEM 4 is disconnected, and finally the telephone line is disconnected to terminate data communication.

In Figure 1, MOBILE-MODEM 4 to DT
Polling sequence PO requesting transmission from E2
LL 301 is sent, and DTE 2 sends EOT 302 denying it because it cannot send the message for some reason.

In Figure 1, MOBILE-MODEM 4 to DT
Polling sequence PO requesting transmission from E2
Sends LL 301, DT'F: 2 cannot send the message for some reason, so negates EOT 30
Send 2.

Next, MOBILE-MODEM 4 sends the polling sequence POLL303 to DTE 2 again,
On the other hand, DTE 2 is ready to send the data, so it sends the message 304 to MOBILE-MODEM 4.
Send to.

MOBILE-MOD double 4 checks the BCC code for errors in the data of message 304, and since there are no errors, DTE? Sends ACKφ, 305 and receives (
Significant data, that is, a text part, of the message 304 is extracted, and this text part is converted into a signal by applying it to the data part of the data frame format of the second transmission frame format shown in FIG. 20].

LAND-MODEM that received message 201
3 is an F'C which decodes the Burgle/(-gar code part of the message 20 and detects the error contained in the decoding of
8 (CRC) code and found an error, a negative response NAK 2 requesting retransmission with a signal in the control frame format of the second transmission frame format shown in FIG.
02 to MOBILE-MODEM 4.

MOBILE-MODEM that received NAK 202
4 sends the same message as the message 201 stored in the MOBILE-MODEM J (the stored message 201 is deleted upon receiving ACK) to the LAND-MODEM 3 as a retransmission message 203.

LAND-MODEM 3 decodes the Haak9 Luberger code of the retransmitted message 203, checks the Fe2 (CRC) code included in the decoding, and since there is no error as a result, sends an acknowledgment ACK 204 to MOBIIJ.
- Sends the message to MODEM 4, extracts the data part of the message 203, and sends the data to the BS shown in FIG.
The C procedure is applied to the text part in the transmission frame format, converted into a signal, and sent to HO8T1.

HO8T 1 checked the BCC code for error detection in the received message 108 and found no error, so it sent an acknowledgment A.
CKφ, 109 is returned to LAND-MODF, M3.

LAND-MODEM 3 received ACKφ, 109
Since there is no information to be sent to HO8T1, it sends EOT No. 10 as a negative response.

Next, since a message to be transmitted from the HO8T 7 side to the DTE 2 is generated, SEL 71 of the selecting sequence is sent to the LAND-MODEM 3.

LAND-MODEM3 that received SEL 111 is able to receive it, so it sends an acknowledgment ACKφ and 112 to HO8T.
Send on 7.

HO8T 7, which received ACKφ, 112, sends a message 113 to LAND-MODEM 3.

LAND-MODEM 3 received ACKJ for HO8T 1 since there was no data error in the received data.
, message 11 received along with sending back 114
Message 2 is extracted by extracting the text part, which is the pig part of message 2, and converting it into a signal by applying the code of this text part to the data part of the data frame format of the second transmission frame.
Send MOBILE-MODEM 4 as 05.

MOBILE-MODEM 4 is the received message 2
05...-r lever decodes one code part, checks the Fe2 (CRC) code in the decoding, finds an error, and requests retransmission NAK 206 to LAND-MODE
Send to M3.

LAND-MODEM 3, which received NAK 206, retransmits the same message as message 205 stored internally as message 207 and switches it to MOBILE-MODE.
Send to M4.

MOBILE knee MOD bladder 4 received message 20
After decoding the Badelberger code part of 7 and checking the Fe2 (CRC) code in the decoded signal, there was no error, so ACK 201 to LAND-MODEM 3.
j and sends a selecting sequence SEL 315 to the DTE2.

DTE 2 sends ACKφ, 316, to indicate that reception is possible.
Return it to OBILE-MODro 4.

MOBILE-MODEM 4 is LAND-MODEM
It returns ACK 20g to s, extracts the data portion from the received message 207, converts the data into a signal by applying it to the text portion of the transmission frame format of the BSC procedure shown in FIG. )317
It is sent to DTE 2 as

DTE 2 checks the BCC code in the received message 317 and returns ACK7, 318 since there is no error.

Finally, MOBILE-MODEM 4 has no message to send to DTE2, so it sends a negative response EOT 319.
and the HO8T 1 side sends back the polling sequence P
Send OLL 116 and LAND-MOD'm 3
Since there is no message to send, a negative response EOT 117 is returned and the data communication is terminated.

The first transmission frame procedure (HDLC procedure) of the present invention when there is a data error using the signal formation of the second transmission frame of the second transmission control procedure of the present invention shown in FIGS. 5 and 6 The transmission control procedure of the second embodiment of the present invention based on the transmission control procedure of No. 2 will be explained with reference to FIG.

Between HO8T 1 and LAND-MODEM 3 and DTE
2 and MOBILE/MODEM 4 respond with signals in the HDLC procedure (first transmission control procedure) and HDLC procedure transmission frame format (first transmission frame format), and LA
ND-MODEM 3 and MOBILE・MODEM
4, the second transmission control procedure and the second
It responds with a signal in the transmission frame format.

Before entering the data link level transmission control procedure shown in Figure 2, as mentioned above, call the other party from the telephone on either the HO8T J side or the DTE X side, create a telephone line, and then use this telephone line. Create a data communication route with the configuration shown in Figure 7.) (O8T1, LAND, MO
DEM 3 questions and DTE 2 and MOBILE-MOD
A physical level transmission control procedure is performed between the IIm4s, and they are connected at the physical level.

Also, after the data link level transmission control procedure is completed, the second
Although not shown in the diagram, HO8T1 and DTE on a physical level
Finally, the telephone line is disconnected and the data communication is terminated.

In Figure 2, the SNRM (Set Normal Response Mode: S
et Normal Re5ponse Mode)
501 from HO8T1 to LAND'MODEM 3, and UX' (Unnumbered Acknowledgment) for LAND-MODEM 3 to accept the data link establishment.
edgement ) 502 response is returned.

Similarly, the DTE X side sends the command SNRM 701 to MOBILE-MODEM 4 to establish a data link.
MOBILE-MODEM 4 returns a response from UA 702 to accept.

Through the above transmission control procedure, a data link is established between f(O8T 1 and DTE 2).

In order to send a message from DTE 2 to HO8T 1, DTE 2 sends a message in the Eframe format of the HDLC procedure! Send frame 703 to MOBILE-MODEM 4. MOBILE-MODEM 4 sends l frame 703
The Fe2 (CRC) code of the HDLC hand condyle was checked and there were no errors, indicating that it was received normally.
ive Ready) 704 back to DTE 2.

MOBILE-MOIEM 4 is the received l frame 7
The code of the information part of 03 is extracted and converted into a signal formed by applying this information part code to the data part of the data frame format of the second transmission frame format shown in FIG. 2(b).
It is sent to ODEM 3 as a message 601.

LAND-MODEM 3 that received message 601
No. 1 - The Gluberger code part was decoded, and the F'C8 (CRC) code included in this decoding was checked and an error was found, so the control frame format of the second transmission frame format shown in Figure 3 was changed. MOBILE-MODEM 4 sends a negative acknowledgment NAK 602 requesting retransmission with a signal of
Send it back to

MOBILE-MODEM that received NAK 602
4 sends the same message as the message 601 stored in the MOBIIJ/MODEM J (the stored message 601 will be deleted upon reception of ACK) to the LAND-MODEM 3 as a retransmission message 603.

LAND-MODEM 3 is retransmission mode: y se--)
60317) Bar 'I' Bar decodes one code part and checks the Fe2 (CRC) code included in the decoding and there is no error, so acknowledges ACK 604
is returned to MOBILE-MODEM 4, the data portion of message 603 is extracted, and the data is sent to MOBILE-MODEM 4.
HO8T is converted into a signal by applying the HDLC procedure shown in the figure to the information part of the frame format,
Send to 1.

HO8T 1 receives Fe2 (
The CRC) code is checked and there is no error, so an acknowledgment response RR504 is returned to the LAND-MODEM 3.

Next, in order to transfer the message from HO8T 1 to DTE 2, HO8T 1 switches the I frame 505 to LAND-MODE using the HDLC procedure I frame format signal.
Send to M4.

LAND-MODEM 3 that received Eframe 505
checked the Fe2 (CRC) code of Eframe 505 and found no error, so sent the acknowledgment response RR506 to H.
At the same time, the code of the information part of the l frame 505 is extracted, and the code of this information part is applied to the data part of the data frame format of the second transmission frame format, converting it into a signal formed by sending it back to O8T 1, and transmitting it as a message 605 to MOBILE. -M
Send to ODEM 4.

MOBILE-MODIi that received message 605
χ4 decodes the Haak 1 Luberger code part of the message 605, and Fe2 (C
RC) code was checked and there was no error, so an acknowledgment ACK6i (76) of the signal in the control frame format of the second transmission frame format was returned to the LAND-MODEM 3, and the data part of the message 605 was extracted. The data part is converted into a signal by applying the information part in the frame format of the HDLC procedure, and is sent as a frame 705 to the DTE!.

DTB2 receives Fe2 (CR
C) The code is checked and there is no error, so an acknowledgment response RR706 is sent back to MOBILE-MODEM 4.

This is a case where DTE 2 disconnects the telephone line from the DTB 2 side because there is no more data to transfer to HO8T 1, and HO8T 1 knows that the telephone line on the DTE Z side has been disconnected and switches to the HDLC to stop operating. Step D
ISC (Disconnect: Diaconnect)
LAND-MODEM 3 sends the 507 command to LAND-MODEM 3 and receives DISC 507.
sends back a response UA50B to accept the intention. After that, as mentioned above, HO8T 7 and MO
The physical level connection between BILE and MODEM 3 is terminated, and the power is turned off.

Conversely, if HO8T Z disconnects the telephone line from the HO8T J side because there is no data to transfer to DTE 2, DTE 2 becomes aware of the disconnection of the telephone line on the HO8T I side and shifts to the operation stop state. Therefore, the DISC707 command of the HDLC procedure is set to MOBILE-MODE.
LAND- which sent to M4 and received DISC707
MODEM 3 returns a response signal UA70B to accept the intention. Thereafter, as described above, the physical level connection between the DTB 2 and the MOBILE-MODEM 3 is terminated, the power is turned off, and all data transmission and reception is completed.

As described above, a transmission control procedure, etc. is a combination of an SC procedure (first transmission control procedure) and a second transmission control procedure, or a combination of an HDLC procedure (first transmission control procedure) and a second transmission control procedure. LAND-MODEM for executing
The modem of the present invention found in MOBILE-MODEM 3 and MOBILE-MODEM 4 will be explained.

CCITT's conventional V-series modem, which is applied to general public telephone networks, does not have countermeasures against fading phenomena, urban noise, shadowing, etc. peculiar to mobile radio, and its error control method is also based on ARQ (Automatic RQ).
This method is ineffective for wireless transmission paths where fading occurs.

The modem of the present invention has a data error rate of 1 including burst errors.
Even in a poor line of 0-3, FEC (Forward Error Correction)
By adopting an error control method based on the ``orrection'' method, highly efficient, highly stable, high-speed data communication is possible.

FIG. 3 is a block diagram of a modem according to a first embodiment of the present invention, and this modem will be explained below.

801 in Figure 3 is an R8-23 that connects to a data terminal device or general-purpose converter, etc. and sends and receives data to and from the modem.
2-C interface, 802 is a CPU.

The main control unit is composed of a ROM and a RAM, and performs mutual conversion control between the first transmission control procedure and the second transmission control procedure, a data transmission/reception buffer, system management of the entire modem, etc., and 803 is a transmission unit that sends out to the line. The data bar encodes the data into a code, the data received from the line is decoded and the error detection function is performed, and the data is retransmitted in response to a retransmission request from the receiving modem in response to a data error on the transmission path. an error control unit 80 consisting of a retransmission function;
4 is a signal conversion unit that includes a modulator for transmitting data based on the CCITTOV series, a demodulator for receiving data, a 2100 Hz tone generator, a detector, etc., and 805 is a signal converter that connects a general telephone to a wired or wireless transmission line. NCU (Network Control Unit) interfaces with car telephone equipment and switches between general telephone and modem.
Network Control Unit) circuit,
Dial generation circuit 1. A line interface consisting of a call flow stone detection unit, etc., 806 is a Syrian/
80 is a wireless interface that is composed of a no-cellarel converter, a buffer, etc. and is connected to a car telephone device; 807 is an input/output port for a data terminal device, a general-purpose computer, etc.;
8 is an input/output port of a wired or wireless transmission line, 809 is an input/output port of a general telephone, and 810 is an input/output port of a car telephone device.

The operation of the main control unit 802 will be explained.

The main control unit 802 includes CPU, ROM, RAM and C
It consists of a PU interface circuit, etc., and a program for flow control and fixed data are written in the ROM.
The RAM is used as a temporary storage memory for executing the transmission/reception/muffer program corresponding to the data terminal device or the general-purpose converter side, and the transmission/reception buffer program corresponding to the line side.

The operation of the main control unit when data flows from the data terminal device side to the line side will be explained.

Data in the first transmission frame format sent from a data terminal device or the like is stored in the reception buffer of the RAM. C.P.
U inspects the type and content of the data in the first transmission frame format stored in this reception buffer and checks for errors, and transmits the first transmission frame format (BSC, HDLC, etc.) to the data terminal device.
respond with a signal. Next, the CPU sends the received data stored in the receive buffer, for example, a text portion in the BSC procedure transmission frame format that is the first transmission frame format, but a text portion that is not yet transmitted in the HDLC procedure that is the first transmission frame format. In the frame format, if an information part is included, it is extracted and transferred to the transmission buffer on the line side.

Further, the CPU converts the signal in the first transmission frame format transferred to the transmission buffer on the line side into a signal in the second transmission frame format, and outputs the signal to the signal conversion section.

Note that when the CPU converts into a signal in the second transmission frame format, the portion that is converted by the signal conversion unit 804 using hardware is excluded.

On the other hand, the operation of the main control unit when data flows from the line side to the data terminal side will be explained.

The decoded signal of the /%)f Luberger code sent from the signal converter 804 is temporarily stored in a receiving buffer on the line side of the RAM. Here, the CPU checks the type of data (control frame/data frame) stored in the receiving buffer on the line side and responds to the line side with a signal in the second transmission frame format. If the data stored in the reception buffer on the line side includes an information data section, the CPU extracts it and transfers it to the transmission buffer corresponding to the data terminal device side. Furthermore, the CPU converts the data transferred to the transmitter 7a on the data terminal device side into a signal in the first transmission frame format (BSC, HDLC, etc.) of the data terminal device, and outputs it to the R8-232-C interface. do.

FIG. 4 is a block diagram of a modem according to a second embodiment of the present invention, and will be briefly described below. In FIG. 4, all of the functions of the signal converter 8θ4 in the configuration shown in FIG. 3 are program-controlled by the CPU, so the configuration simply omits the signal converter 1304, which was processed by software. The operation is the same as the modem shown in Figure 3.

The reason for configuring the signal converter 804 with hardware is mainly due to the communication speed of the data communication system.
This is a case where the PU processing takes too long to complete in time.

(Effects of the Invention) As explained in detail above, the first advantage of the present invention is that the first transmission control procedure (BSC procedure,
HDLC procedure, etc.) and the first transmission frame format (BSC
It is easy to handle the general procedures and signal formats described above, which are signals in the transmission frame format for HDLC procedures and the like.

The second advantage is that the line error rate between modems is 10-5.
By applying the second transmission control procedure and the second transmission frame format signal to bad lines, retries due to frequent data errors and retries due to timeouts due to no response from the other party are reduced, improving transmission efficiency. Enables good and stable data communication.

[Brief explanation of the drawing]

Fig. 1 shows the transmission control procedure of the first embodiment of the present invention, Fig. 2 shows the transmission control procedure of the second embodiment of the invention, and Fig. 3 shows the configuration of the modem of the first embodiment of the invention. 4 is a configuration diagram of a modem according to a second embodiment of the present invention, FIG. 5 is a second transmission frame format of a data frame of the present invention, and FIG.
A second transmission frame format of the control frame of the present invention, FIG. 7 is a block diagram of a data communication system for public automobiles, and FIG. 8 is a configuration example of a conventional data communication system.
Figure 9 shows the first example of the conventional polling/selenoting method.
10 is an example of the second BSC procedure of the conventional -j) selecting/selecting method, and FIG. 11 is an example of the BS
Figure 12 shows the transmission frame format of polling/selecting control messages in the BSC procedure; Figure 13 shows the transmission frame format of I and U frames in the HDLC procedure; Figure 14 shows the transmission frame format of the H frame.
This is the transmission frame format of an S frame in the DLC procedure. 1... General-purpose host computer/computer (HO8T), 2...
・Data terminal device, 3...LAND-MODEM,
4...MOBILE/MODEM, 5...Car telephone device, 6...Wireless transmission path, 7...Wireless base station, 8
...Car telephone station, 9...Radio line control station, 10.
...-Membrane switching network, 801...R8-232-C interface, 802... Main control section, 803... Error control section, 804... Signal conversion section, 805... Line interface, 8θ6.・Wireless interface, 807・
... Input/output ports of data terminal equipment and general-purpose computers, etc., 808... Input/output ports of wired or wireless transmission lines, 809... Input/output ports of general telephones, 810...
- Input/output port of car phone device.

Claims (1)

[Claims] 1. A primary station data device connected to the primary station modem device and a secondary station modem device connected to the primary station modem device via the primary station modem device and the secondary station modem device connected to the line.2. In a transmission control method for mutual data communication between next station data devices, (a) the primary station or secondary station modem device is connected to the primary station or secondary station modem device to form one station; and (b) a data device connected to the primary station or secondary station modem device and forming one station. (c) means for commanding and responding with a first transmission control means and a signal in a first transmission frame format; a second transmission control means for commanding and responding to a partner station modem device of the station modem device; and a means for converting into a signal in a second transmission frame format; (d) a partner station of the primary station or secondary station modem device; A second transmission control procedure and a second transmission frame format signal from the modem device are transmitted to a data device connected to the local modem device of the primary station or the secondary station and constitutes one station, and a first (e) between the modem devices of the primary station and the secondary station, a second transmission control procedure and a means for converting the signal into a signal in the first transmission frame format; (a) and (b) of the means for commanding and responding with signals;
, (c), (d), and (e), and a first station for transmitting and receiving data between the primary station modem device and the primary station data device and between the secondary station modem device and the secondary station data device. With the transmission control procedure and the signal in the first transmission frame format, the second transmission control procedure and the signal in the second transmission frame format are used for data transmission and reception between the primary station modem device and the secondary station modem device. Characteristic data communication transmission control method. 2. In a system in which both data devices communicate data with each other via a modem, (a) input/output for transmitting and receiving data with the data device side, and output corresponding to data input of the modulation section of the analog telephone line modem and analog (b) input/output means having an input corresponding to the data output of the demodulator of the telephone line modem; (b) a first transmission control procedure and a first transmission frame format signal for the input/output of the data device; (c) The input/output corresponding to the data side of the modulation/demodulation section of the analog telephone line modem is handled by a second transmission control procedure and a second transmission frame format signal. (d) converting a signal in a first transmission frame format input from the data device into a signal in a second transmission frame format to correspond to data input to a modulation section of the analog telephone line modem; (e) decoding the Hagelberger-encoded data portion of the second transmission frame format signal input from the data output of the analog telephone line demodulator; and the decoded signal. If there is an error, a negative response requesting retransmission is sent to the output corresponding to the data input of the modulation section of the analog line modem, and if there is no error, a positive response is sent. a conversion control means for converting the decoded signal of the Hagelberger code into a signal in a first transmission frame format and outputting it to the data device side, enabling data communication with high transmission efficiency even on a line with many burst errors. A modem device characterized by: