KR100486521B1 - Apparatus and method for transmitting fax data in voice communication system - Google Patents

Abstract

The present invention relates to a fax data transmission apparatus and method for effectively performing a fax service in a voice communication system using a vocoder. When a fax signal is detected from a call signal received from an exchange or a terminal during a voice call, the call signal is transmitted to the vocoder. It transmits to the terminal or the switching center through the inter working function (Inter Working Function).

Description

Apparatus and method for transmitting fax data in voice communication system {APPARATUS AND METHOD FOR TRANSMITTING FAX DATA IN VOICE COMMUNICATION SYSTEM}

The present invention relates to a voice communication system using a vocoder, and more particularly, to an apparatus and method for transmitting fax data in a voice communication system capable of effectively performing a fax service.

Recently, with the development of information communication technology and increasing user's desire, the demand for wireless data service that can exchange data information as well as voice is increasing day by day. In order to meet such demands, the wireless voice communication system adds an Inter Working Function (IWF) to the network infrastructure for voice communication to perform a wireless data service.

1 is a block diagram of a conventional voice communication system.

As shown in FIG. 1, the conventional voice communication system includes a fax 100 for generating / restore fax data, a mobile transmitter 200 for transmitting / receiving a fax signal with the fax 100, Voice between a Mobile Switching Center (MSC) 500 and a Base Transceiver Station (BTS) 300 and a Switching Station 500 connected to a public switched telephone network (PSTN) (not shown). And a base station controller (BSC) 400 for transmitting / receiving fax data.

The base station controller 400 decodes a voice signal received from the base station 300 or a vocoder 410 for decoding the voice signal received from the switching center 500, and an interworking function 420 for transmitting and receiving data. It consists of.

The operation of the conventional voice communication system configured as described above is as follows.

When the user of the terminal 200 requests the transmission of the fax data during a voice call, the other party's caller transmits the fax data to the switching center 500 connected to the public telephone network (PSTN) using a fax (not shown) (S100). Switching station 500 transmits a call signal containing the fax data to the base station controller 400 (S110).

The vocoder 410 of the base station controller 400 encodes the received call signal and transmits it to the base station 300 (S120). Accordingly, the terminal 200 decodes the call signal input through the base station 300 in a vocoder (not shown) (S130) and then transmits the call signal to the fax 100 (S140), so that the fax 100 faxes the call signal. Restore data to perform a fax service (S150).

However, in general, the vocoder performs encoding optimized for speech by imitating the generation principle of speech. In this case, all waveforms, sizes, and frequency information of the original signal are broken and encoded. Therefore, when the fax data transmitted from the switching center is encoded in the vocoder of the base station controller, the fax data is distorted, so that the fax connected to the terminal cannot restore normal fax data.

In addition, in the conventional voice communication system, transmission of fax data from the base station controller to the fax connected to the terminal is almost impossible due to distortion by the vocoder of the terminal and the base station controller. As described above, the conventional wireless voice communication system has a problem in that it is not possible to effectively perform a fax service due to distortion of fax data by a vocoder and also cannot perform a two-way fax service.

Accordingly, an object of the present invention is to provide a fax data transmission apparatus and method capable of effectively performing a fax service in a voice communication system.

Another object of the present invention is to provide a fax data transmission apparatus and method capable of performing one-way and two-way fax service in a voice communication system.

In order to achieve the above object, the fax data transmission apparatus of the voice communication system according to the present invention transmits the fax data through an interworking function (IWF) when a fax signal is detected from a call signal input during a voice call.

In order to achieve the above object, a fax data transmission apparatus of a voice communication system according to the present invention includes: a vocoder for encoding / decoding a call signal; Interworking function (IWF); A switch for switching the received call signal to a vocoder or an interworking function (IWF); A fax signal detector for detecting a fax signal from a call signal; When the fax signal is detected, characterized in that the control unit for controlling the switch to switch the call signal to the interworking function (IWF).

Fax data transmission method of the voice communication system according to the present invention for achieving the above object comprises the steps of receiving a call signal; Detecting a fax signal from the received call signal; It is characterized by consisting of the process of switching the call signal to the vocoder or interworking function (IWF) according to the fax signal detection result.

Hereinafter, exemplary embodiments of the present invention will be described with reference to the accompanying drawings.

3 is a block diagram of a fax data transmission apparatus of a voice communication system according to the present invention, which includes a fax data control apparatus 41 in a base station controller 400. As shown in FIG.

The fax data controller 41 includes a vocoder 410 for encoding / decoding a call signal; An interworking function (IWF) 420 for data transmission; A first fax signal detector 430 for detecting a fax signal from the received call signal; A second fax signal detector 460 for detecting a fax signal from the call signal decoded by the vocoder 410 and a controller for generating a switch control signal when the fax signal is detected by the first and second fax signal detectors 430 ( 440; The first and second switches 450A and 450B switch the call signal to the vocoder 410 or the interworking function (IWF) 420 according to the switch control signal output from the controller 440. In this case, the first and second switches 450A and 450B are connected to the first and second transmitting / receiving nodes (not shown) of the base station controller 400, respectively.

The first fax signal detector 430 includes a fax tone detector 10 for detecting a fax tone from a call signal, and a preamble signal detector 11 for detecting a preamble signal from the call signal. do.

The second fax signal detector 460 includes a modified fax tone detector 20 for detecting a fax tone from the decoded call signal, and a modified preamble signal detector for detecting the preamble signal from the decoded call signal. Modified Preamble Signal Detector).

Referring to the drawings the operation of the fax data transmission apparatus of the voice communication system according to the present invention configured as described above is as follows.

The fax data transmission apparatus according to the present invention detects the fax signal from the received call signal as shown in FIG. 4 (S200, S210), and switches the call signal to an interworking function (IWF) rather than a vocoder to the receiving side. By transmitting the received fax to restore the fax data from the call signal to perform a normal fax service (S220) (S230).

First, the fax data transmission process from the exchange station 500 to the fax 100 will be described.

As shown in Fig. 3 and Fig. 5, when transmission of fax data is requested from the user of the terminal 200 during a voice call (voice mode), the other party's caller faxes to the switching center 500 using a fax (not shown). After transmitting the data, the switching center 500 transmits the call signal including the transmitted fax data to the base station controller 400.

In the voice mode, terminals b and e of the first and second switches 450A and 450B are connected to terminals a and d so that a call signal (voice signal) can be input to the vocoder 410. Call signal transmitted from the switching center 500 is input to the vocoder 410 through the switch 450A (S300). The fax signal detector 430 uses a fax tone detector 10 and a preamble signal detector 11 to send a fax signal, for example, a fax tone of 2100 Hz and a preamble signal of 1850 Hz or 1650 Hz, from a call signal input to the vocoder 410. Is detected and output to the control unit 440 (S310).

The control unit 440 controls the first and second switches 450A and 450B according to the fax tone detection signal and the preamble signal detection signal output from the fax signal detection unit 430 to control the call signal to the vocoder 410 or the intercom. Switching to working function (IWF) 420. That is, the controller 430 first checks whether a fax tone is detected by the fax tone detector 10 and then checks whether a preamble is detected by the preamble signal detector 11 (S320 and S370). As a result of the check, when at least one of the fax tone and the preamble signal is detected, the controller 440 controls the first and second switches 450A and 450B to change the operation mode of the base station controller 400 from the voice mode to the data mode. Switch.

That is, when a fax signal is detected from the call signal, the controller 440 outputs a switch control signal to the first and second switches 450A and 450B, so that the terminals b, e are the terminals c, By switching to (f), the call signal including the fax data is output to the second switch 450B directly through the first switch 450A and the interworking function (IWF) 420 without passing through the vocoder 410. (S330).

Therefore, since the undistorted call signal in the vocoder 410 is transmitted to the fax 100 through the base station 300 and the terminal 200 (S340), the fax 100 restores the fax data from the received call signal to normal. It is possible to perform a fax service (S350).

On the other hand, if neither the fax tone nor the preamble signal is detected in the process (S320, S360), the control unit 440 continues to maintain the voice mode (S370).

Next, the fax data transmission process from the fax 100 to the exchange 500 is as follows.

In general, the fax data transmitted from the fax 100 is encoded by the terminal 200 and then input to the base station controller 400 through the base station 300, and the call signal input to the base station controller 400 is a vocoder 410. Is decoded and then transmitted to the switching center 500 connected to the public switched telephone network (PSTN). However, since the call signal is distorted by the vocoder 410, the second fax signal detection unit 460 is a crystal paxstone detector 20 and the crystal preamble signal detector 21 in consideration of the linear distortion characteristic of the vocoder 410. Configure.

As shown in FIG. 6, when transmission of fax data from the other party's caller is requested during a voice call (voice mode), the user of the terminal 200 receives the fax data using the fax 100 connected to the terminal 200. send. The transmitted fax data is encoded by the terminal 200 and then transmitted to the base station controller 400 through the base station 300.

   Since the base station controller 400 is in the voice mode, the call signal transmitted from the base station 300 is decoded after being input to the vocoder 410 through the switch 450B. The second fax signal detector 460 detects a fax signal from the call signal decoded by the vocoder 410. For example, the second fax signal detector 460 detects a fax tone of 2100 hz using the modified fax tone detector 20, and then corrects the preamble signal detector. The preamble signal represented by 1850 Hz or 1650 Hz is detected using 21 (S400 and S410).

The control unit 440 controls the first and second switches 450A and 450B according to the fax tone detection signal and the preamble signal detection signal output from the fax signal detection unit 460 to transmit the call signal transmitted from the base station 300. To the vocoder 410 or the interworking function (IWF) 420. That is, the controller 440 first checks whether a fax tone is detected by the modified fax tone detector 20 and then checks whether a preamble is detected by the modified preamble signal detector 21 (S420 and S460). As a result of the check, when at least one of the fax tone and the preamble signal is detected in the call signal, the controller 430 controls the first and second switches 450A and 450B to change the operation mode of the base station controller 400 in the voice mode. Switch to the data mode (S430).

When a fax signal is detected from the call signal decoded by the vocoder 410, the controller 440 outputs a switch control signal to the first and second switches 450A and 450B so that the terminals (b) and (e) Call signals received from the base station 300 by switching to the terminals (c) and (f), respectively, are directly transmitted through the second switch 450B and the interworking function (IWF) 420 without passing through the vocoder 410. It is outputted by one switch 450A.

Therefore, the call signal transmitted from the base station 300 is transmitted to the fax (not shown) connected to the public telephone network (PSTN) through the switching center 500, so that the other party's caller can receive normal fax service (S440, S450). ).

On the other hand, if neither the fax tone nor the preamble signal is detected in the process (S420, S460), the controller 440 continues to maintain the voice mode (S470).

In addition, the present invention has been described using the fax data transmission apparatus of the voice communication system provided in the base station controller 400 for convenience of description, but is not limited thereto, and may be applied to any voice communication system using a vocoder. have.

7 is a block diagram of a fax data transmission apparatus according to another embodiment of the present invention.

Another embodiment of the present invention is an example in which the fax data control device 41 is applied to the terminal 200, but is not limited thereto. The same configuration may be applied to the base station 300.

As described above, the fax data transmission apparatus of the voice communication system according to the present invention performs an effective fax service by transmitting the corresponding call signal through a separate interworking function (IWF) instead of the vocoder when the fax signal is detected from the call signal. It can work.

In addition, the fax data transmission apparatus of the voice communication system according to the present invention has an effect of providing a one-way and two-way fax service by providing a fax signal detection device in consideration of signal distortion by a vocoder.

In addition, the present invention has been described with reference to the embodiments shown in the drawings, which are merely exemplary and will be understood by those skilled in the art that various modifications and equivalent other embodiments are possible. . Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

1 is a block diagram of a conventional wireless voice communication system.

2 is a flowchart showing a process of transmitting fax data in FIG.

3 is a block diagram of a fax data transmission apparatus of a wireless voice communication system according to the present invention.

Figure 4 is a flow chart illustrating a fax data transmission method of a wireless voice communication system according to the present invention.

Fig. 5 is a flowchart showing a process of transmitting fax data from the base station to the switching center in Fig. 3;

Fig. 6 is a flowchart showing a transmission process of fax data from the switching center to the base station in Fig. 3;

7 is a block diagram of a fax data transmission apparatus of a wireless voice communication system according to another embodiment of the present invention.

*** Explanation of symbols for the main parts of the drawing ***

100: fax 200: terminal (MT)

300: base station (BTS) 400: base station controller (BSC)

500: exchange office (MSC)

Claims (10)

delete delete delete A vocoder for encoding / decoding a call signal; Interworking function (IWF); A switch for switching a received call signal to the vocoder or interworking function (IWF); A fax signal detector for detecting a fax signal by detecting a fax tone and / or a preamble signal in the call signal decoded by the vocoder and the received call signal, respectively; And a control unit for controlling the switch to switch the call signal to the interworking function (IWF) when the fax signal is detected. delete The method of claim 4, wherein the switch A first switch connected to the front end of the vocoder and the interworking function IWF; And a second switch connected to a rear end of the vocoder and an interworking function (IWF). delete Receiving a call signal; Detecting a fax signal by detecting a fax tone and / or a preamble signal in the received call signal; And a method of switching a corresponding call signal to a vocoder or an inter working function according to the fax signal detection result. delete The method of claim 8, wherein the switching process Checking whether a fax tone detection signal or a preamble detection signal is input; And converting a corresponding call signal into an interworking function when one of the paxton and preamble detection signals is input.