JPH04104529A - Data communication system for digital cellular - Google Patents

Abstract

PURPOSE:To transparently communicate data between a DCE(data communication equipment) connected to a line system and another DCE connected to a digital cellular line network by providing a means which automatically selects a MODEM to be used in a wire system, an audio/data automatic switching means, and a data packet making means which standardizes communication on a radio network. CONSTITUTION:A mobile station 101 detects the transmission speed and the state signal of a connected terminal 100 and transmits them to a base station 102. The base station 102 selects a MODEM corresponding to the transmission speed sent from the mobile station out of plural MODEMs different in transmission speed and controls this MODEM by the state signal to input data and transmits the state signal of the MODEM and outputted data to the mobile station 101. The mobile station receives them and outputs them to the terminal 100. That is, MODEMs provided in the base station 102 are selected and controlled by the mobile station 101, and selected MODEMs are standard physical MODEMs. Thus, it is unnecessary to store transmission data in the system.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a data communication system in a digital cellular network.

(Prior Art) One of the conventional data communication systems in a digital cellular network is rIEEE Vehicle Technique.
ologyConference (1990) P.
336-340 J, and its system configuration is shown in FIG. In the figure, data terminal (DTE)
) 200 is connected to the asynchronous terminal processing 201, and the asynchronous terminal processing 201 is connected to P A D (Packet As5c
The PAD 202 is connected to the data link layer 203, and the data link layer 203 is connected to the TDMA radio section 204.
It is connected to the. Also, the DT connected to the wired line
P210 is a wired line DCE (Date Camr
209
The wired line DCE209 is connected to the wired line network (P
STN). On the other hand, in the base station, the TDMA radio unit 205 is connected to the data link layer 206, the data link layer 206 is connected to the PAD 207, and the
D207 is connected to a wired line protocol section 208.

In this system, the asynchronous data sent from the DTP 200 is processed by the asynchronous terminal processing 201.
Stop bits etc. are removed and converted to synchronous data. The data converted into synchronous data is packetized by the PAD 202 and output to the data link layer 203.

The data link layer 203 transfers the packetized data using a protocol specific to the radio line to the TDMA radio unit 1o4.
105 to the data link layer 206 of the base station. When the PAD 207 receives an error-free data packet from the data link layer 206, it decomposes the packet into synchronization data. The decomposed synchronization data is sent to the wired line protocol section 208. Here, the wired line protocol unit 208 and the wired line DCE 209 having the same protocol transmit data between each other, and the synchronized data is sent to the DTP 210. In this way, in the above system, communication is independent between the wireless line system and the wired line system. Therefore, there is no error control in the wired line D.
When communication is performed with the CE, since the wireless line has its own error control, there are no data errors on the wireless line, and data errors only occur on the wired line system.

(Problems to be Solved by the Invention) However, in the system with the above configuration, (a) the protocol is independent for the wired line and the wireless line, so although the wired line completes normally, the wireless line quality deteriorates. If the system terminates abnormally due to a faulty system, there is a problem in that there is no means to notify the DTP connected to the wired line of the abnormal termination. In particular, Group 3 (hereinafter referred to as G3)
This becomes a problem when considering facsimile communication.

(b) If this system supports DCE used in existing wired systems, there is a problem in that the base station must have DCEs with a wide variety of protocols that exist in wired systems.

(C) There is a problem in how and where to switch between DCEs having the various protocols mentioned above.

(d) When transmitting data from a wired line system, if the line quality of the wireless line is poor, it takes time to send and receive data due to data retransmission between wireless protocols. Therefore, it is necessary to control the flow of data between wired line protocols, but the problem is how to set the optimal buffer value.

The present invention has been made to solve the above problems, and includes a means for negotiating transmission speed between a mobile station and a base station, a means for automatically selecting a modem to be used in a wired system, and a voice/data A means for automatic switching of data and a means for data packetization to unify communication on the wireless line network are provided, and data communication between the DCE connected to the wired line system and the DCE connected to the digital cellular line network is implemented. The purpose is to provide a transparent transmission system.

(Means for Solving the Problems) In order to achieve the above object, the present invention includes a means for detecting the transmission rate and status signal of a terminal and transmitting the detected signal to a base station, and a means for receiving a modem status signal transmitted by the base station. a plurality of modems having different transmission speeds; a means for receiving transmission speeds and status signals transmitted by the mobile station; A base station is provided with means for selecting a modem, and means for controlling the selected modem with the status signal and transmitting the status signal of the modem to a mobile station, and the terminal performs data communication via the modem. It is something.

Further, in the present invention, the mobile station and the base station are provided with switches for switching between data and voice, respectively, and data or voice is transmitted by controlling each of the switches based on information from the mobile station side terminal.

(Operation) A mobile station detects the transmission rate and status signal of a connected terminal, and transmits these together with data from the terminal to the base station. The base station receives the transmission rate, status signal, and data transmitted by the mobile station, selects a modem corresponding to the transmission rate sent by the mobile station from among multiple modems with different transmission rates, and controls it using the status signal. , inputs the data, and transmits the modem status signal and output data to the mobile station. The mobile station receives the status signal and data and outputs it to the terminal.

In this way, the selection and control of the modem installed in the base station is performed from the mobile station, and all selected modems are standard physical modems, and in wireless lines, the selection and control of the modems installed in the base station are performed by the mobile station. It does not interfere with the protocol in any way.

Note that modem selection at the base station is performed even during communication if there is an instruction from the mobile station.

Further, a switch for switching between voice and data is provided in the mobile station and the base station, and these can be automatically switched based on information from the terminal of the mobile station, so that voice or data can be transmitted as appropriate.

(Example) FIG. 1 is a system configuration diagram showing an embodiment of the present invention.

In the figure, the DTE 100 on the mobile station side is the mobile station 10
The mobile station 101 is connected to the base station 102 through a wireless link. Additionally, within the mobile station 101, there is an RA (Rate Adaptation) that controls the transmission rate.
It has 103. In the base station 102, there is a R A (Rate Adaptation) 1 that controls the transmission rate.
Modem pool 1 that stores modems standardized as 04
05. Furthermore, the base station 102 is connected to the wired line network 10.
6 and the base station 102 is connected to r S D N (In
tegrated 5 services Digital
network) 107. Wired line network (PSTN: Public 5w1tched Te1
ephone Network) 106 has DTE
108 is connected, and TE109 is connected to l5DN107.

For example, when transmitting data from the mobile station 101, the DTE 100 on the mobile station side first transmits data to the RA 103 of the mobile station 101.
Specify the transmission speed for . Methods of specification include a method of specifying the transmission rate using a protocol such as HDLC between the DTE 100 and the RA 103, a method of specifying the transmission rate using an external switch, a method of using an AT command, etc. RA103 is DT
The data received from the E 100 is converted into a digital signal that can be applied to a digital format of a digital cellular wireless transmission system (eg, TDMA transmission system). where - as an example CCITT (International Telegraph and Telephone Consultative Committee)
The format of Recommendation V, 110 is used. In addition to the data of the DTE 100, the digital format also includes status information indicating the state of the DTE 100 and a signal indicating the transmission speed. Next, the digital signal is sent to the base station 10 using the digital cellular wireless transmission method.
2. The RA 104 in the base station 102 extracts status information and transmission speed from the digital signal transmitted from the RA 103. Based on this transmission rate, a modem designated by the DTE 100 is selected from the modem pool 105 connected to the RA 104, and data is transmitted to the selected modem. The selected modem connects to the PSTN via PSTN 106.
106 to the DTE 108 connected to the DTE 106 .

The feature of this system is that the mobile station selects the modem in the base station, and the modem in the base station does not have a protocol and uses a normal standard modem.
The protocol between the E and the DTE connected to the wired line is transparent.

FIG. 3 is a block diagram showing an embodiment of the mobile station 101 shown in FIG. In FIG. 3, the terminal is connected to a terminal interface unit 300, and the terminal interface unit 30
0 is the encoding section 301, the decoding section 302, and the radio control section 3
05, the encoding section 301 is connected to the switch 303, and the decoding section 302 is connected to the switch 304. Switch 303 is connected to voice encoding section 307 and radio device control section 305. Further, the switch 304 is connected to the audio decoding section 308 and the radio device control section 305. The radio control section 305 is connected to a digital mobile radio 306. Also, the audio encoding section 307 and the audio decoding section 308
is connected to the A/D-D/A converter 309, and the A/D
- A D/A converter 309 is connected to the handset.

Next, the operation of the mobile station shown in FIG. 3 will be explained.

When a terminal transmits data, it first transmits a signal to the mobile station notifying the activation of the data terminal.

When the terminal interface section 300 receives this notification signal, it outputs an audio/data switching signal to the radio control section 305. Here, circuit number 108/2 of the CCITT Recommendation V, 24 interface is used as a means for notifying activation of the data terminal. When the radio control unit 305 receives the switching signal, it instructs a base station (not shown) to switch from the voice signal to the data signal via the digital mobile radio 306. Audio at mobile stations and base stations
The data switching method is performed using protocols used in digital cellular. The audio-data switching signal is also output to switch 303 and switch 304. When the above signal is input to switch 303 and switch 304, switch 303 connects the output of encoder 301 to radio controller 305, and switch 304 connects the output of radio controller 305 to decoder 304. do.

The terminal then specifies to the mobile station the selection of modems at the base station. Upon receiving this designation, the terminal interface unit 300 obtains the transmission rate of the terminal using the method described in FIG. 1 above, and notifies the encoding unit 301 of this transmission rate in the form of a status signal. The encoding unit 301 converts data sent from the terminal via the terminal interface unit 300 into a signal format adapted to the transmission rate specified by the status signal. At the same time, in order to notify the modem of the base station of the terminal status signal, the terminal status signal is added to the signal format and output to the radio controller 305 via the switch 303. For example, in order to specify switching between transmission and reception when the terminal is in half-duplex mode, the terminal status signal is here CCITT V,2.
4, circuit numbers 105 and 106 are used for switching between transmission and reception. When the terminal is transmitting, circuit number 105 is ONL, and when the terminal can receive data, circuit number 10 is ONL.
Turn on 6. Further, in this embodiment, the signal format output from the encoding section 301 is CCIT, for example.
TV, 110(7) signal format was used.

The radio control unit 305 sets the signal format to TDMA.
divided into frames and transmitted to a digital mobile radio.

On the other hand, the TDMA frame received from the base station is sent to the radio controller 305 via the digital mobile radio 306.
is input. The radio control section 305 decomposes the TDMA frame into V, 110 frame formats and outputs them to the decoding section 302 via the switch 304.

The decoding unit 302 decomposes the V and 110 frames and outputs data and status to the terminal interface unit 300. The terminal interface unit 300 analyzes the status and notifies the terminal of the modem status signal of the base station.

FIG. 4 is a block diagram showing an embodiment of the base station 102 shown in FIG. Note that for the sake of simplicity, a one-channel configuration is shown, and the radio system is omitted. In Figure 4,
The output side of the encoder 400 is connected to a data line to the radio system, and the input side is connected to a modem status control section 402, a modem selection section 403, and a switch 404, respectively.

The input side of the decoding section 401 is connected to a data line from the radio system, and the output side is connected to a modem selection section 403, a modem status control section 402, and a switch 404, respectively. The output side of the modem selection section 403 is a switch 404
The modem status section 402 is connected to a switch 404, and the switch 404 is connected to a modem pool 405. Each modem in the modem pool 405 (V, 21. V, 22.
, 32, etc.) is output from the PSTN interface section 4.
Connected to 06. PSTN interface section 406
is connected to the PSTN line exchange, and the control terminal of the PSTN interface section 406 is connected to the voice/data switching signal line from the radio equipment system.

Next, the operation of the base station will be explained based on FIG. 4.

First, a TDMA frame from a mobile station received by a radio system is input to a decoding section 401 via a data line and decomposed into V,110 frames.

After the frame is decoded into data and status, the status is sent to the modem status control unit 402 and the modem selection unit 40.
3 is input. The modem selection unit 403 selects a modem having the transmission speed instructed by the mobile station from the modem pool 405. A modem status control unit 402 analyzes the status and outputs a status signal transmitted from the mobile station to the selected modem. For example, mobile station interface ■, 240 circuit number 108/2 is ON
When V,21 is selected, there is a bit indicating the state of circuit number 108/2 in the received V,110 frame,
The modem status section 402 is notified of the state of the bit. The modem status control unit 402 turns on the circuit number 108/2 of V, 21. The same applies to other circuit numbers 106 and 105. Here, the interface status and transmission rate on the mobile station side are sequentially notified to the base station side. Therefore, it is possible to switch modems during communication. This can be applied to, for example, G3 facsimile communication. Further, the analog signal output from the modem pool 405 is output to the PSTN via the PSTN interface section 406.

Here, voice/data switching is performed based on a voice/data switching signal sent from the mobile station.

That is, the audio/data switching signal is detected by the radio system and input to the control terminal of the PSTN interface section 406 via the audio/data switching signal line. P.S.
Based on this voice/data switching signal, the TN interface section 406 switches the output of the modem in the modem pool 405 to P.
Select whether to output to the NTS line or to output the voice detected by the radio system and sent via the voice line to the PNTS line.

(Effects of the Invention) As described above in detail, according to the present invention, the selection of modems in the modem pool of the base station and the control of the modems are performed by the mobile station, and furthermore, all the modems in the modem pool are standard physical It is a modem and does not intervene in the protocol between the wired line and the terminal connected to the wireless line. Therefore, modems with various protocols running on the existing PSTN can be used. Therefore, if the condition of the wireless line is poor and transmission is not possible, in the conventional method the communication on the wired side ends normally, but the wireless line becomes abnormal and cannot notify the wired line of the abnormal termination. According to the invention, since no intervention is made in the protocol between the terminals, both stations can clearly recognize abnormal termination of the protocol between the terminals. Furthermore, it is possible to automatically switch between voice and data by monitoring the mobile station terminal. Additionally, since both wired and wireless lines are transparent, there is no need to store transmitted data within the system.

From the above, it is applicable not only to modems with normal protocols but also to G3 facsimile communications in which the type of modem is changed many times during communication.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of an embodiment of the present invention, Fig. 2 is a system block diagram of a conventional data communication method, Fig. 3 is a block diagram of a mobile station embodiment, and Fig. 4 is a block diagram of a base station embodiment. FIG. 100...DTE, 101...Mobile station, 102...
・Base station, 103.104...RA, 105...Modem pool, 106...Wired line network (PSTN),
107...l5DN, 109...TE, 300...
・Terminal interface section, 301, 400... Encoding section, 302° 401... Decoding section, 303, 304
．． 404... Switch, 305... Radio control unit,
306... Digital mobile radio device, 307... Audio encoding section, 308... Audio decoding section, 309...
A/D-D/A conversion section, 402...Modem status control section, 403...Modem selection section, 405...Modem pool, 406...PSTN interface section. Patent applicant: Oki Electric Industry Co., Ltd., ~-12

Claims (3)

[Claims] (1) The mobile station is equipped with a means for detecting the transmission rate and status signal of the terminal and transmitting the detected signal to the base station, and a means for receiving the modem status signal transmitted by the base station and outputting it to the terminal. a plurality of modems with different transmission speeds; means for receiving a transmission rate and status signal transmitted by a mobile station; means for selecting a modem corresponding to the transmission rate from the plurality of modems; A data communication system in digital cellular, characterized in that a base station is provided with means for controlling the modem and transmitting a status signal of the modem to a mobile station, and the terminal performs data communication via the modem. (2) The digital cellular data communication system according to claim 1, wherein the means for selecting a modem in the base station selects a modem in accordance with successive changes in transmission rate from a mobile station even during communication. (3) A switch for switching between data and voice is provided in each of the mobile station and the base station, and data or voice is transmitted by controlling each of the switches based on information from the mobile station side terminal. 1. The data communication method in digital cellular according to 1.