KR100357268B1 - Apparatus and method tranfering into data-mode in system using vocoder - Google Patents

Abstract

The present invention is to provide a data service in a system using a vocoder, and in particular, switching to a data mode for providing facsimile service in a voice system using a vocoder, such as a wireless local loop (WLL) system. An apparatus and method for detecting an input signal and switching to a facsimile mode.

The present invention comprises the steps of transmitting a signal at the switching center; Transmitting a signal at the called party; Determining whether the detected signal of the called party is a facsimile signal; And the step of switching to a data mode in the facsimile signal as a result of the determination.

Since the present invention detects a facsimile signal in the facsimile detector and switches to the data mode, data can be transmitted using the facsimile during a call, thereby providing the same service as a general wired network even in a wireless system.

Description

Apparatus and method tranfering into data-mode in system using vocoder}

The present invention is to provide a data service in a system using a vocoder, and in particular, switching to a data mode for providing facsimile service in a voice system using a vocoder, such as a wireless local loop (WLL) system. For this purpose, the present invention relates to an apparatus and a method for detecting an input signal and switching to a facsimile mode.

More particularly, the present invention detects a signal input from a switching center to a base station controller in a facsimile signal detector in the base station controller and switches the data mode so that a fax can be transmitted during a call. It is to provide a service.

In general, a system using a vocoder in the prior art is composed of a vocoder mode for voice calls and a separate data mode for fax transmission.

Therefore, in the system configured as above, it is not possible to convert between vocoder mode and data mode during a call. Therefore, when the user operates the phone, the voice call is set up and the voice is transmitted through the vocoder. The fax is sent using the mode.

1 is a block diagram of a vocoder mode for a voice call and a separate data mode for fax transmission.

Mobile station 10 (MS, Mobile Station) including facsimile, telephone and terminal, base station controller 20 (BSC, Base Station Controller) for controlling the base station, and switching center 30 (MSC, Mobile Switching Center) It is composed.

A vocoder (21) for processing voice inside the base station controller (20); It consists of a data processing part 22 (IWF, Inter Working Function) which processes data.

Also, the vocoder has an encoder 21a for encrypting the PCM data transmitted from the switching center 30, a decoder 21b for decoding the packet data transmitted from the mobile station 10, and converts the input data into PCM data. PCM 21c is included.

Referring to the operation of switching to the data mode in the system using the vocoder of Figure 1 as follows.

First, the general operation of the vocoder is explained.

There are three methods for compressing speech: a waveform coding method for quantizing a waveform of a speech as it is, a parameter extraction method for quantizing a speech parameter using speech modeling, and a hybrid coding method combining the above two advantages.

In general, one of the most commonly used to compress and transmit voice in digital communication system is vocoder. This vocoder extracts voice parameters and performs the remaining signal with waveform coding. It is possible to use the voice compression method of the hybrid coding method, and in Korea's mobile communication system, 8 Kbps QCELP (Qualcomm Code Exicted Linear Prediction), 13.3 Kbps QCELP and 8 Kbps Enhanced Variable Rate Coder (EVRC) are used.

The hybrid coding method used in the vocoder first extracts the speech parameter and then waveform-codes the rest of the residual signal. Therefore, it shows relatively high sound quality when coding the voice. However, when coding non-voice such as music or single / dual tone, the waveform Distortion is a disadvantage that occurs. In other words, if the vocoder is used to transmit a fax, the signal is distorted, resulting in damage to the fax information.

Since the vocoder cannot be used to transmit a fax, the vocoder system has a data mode for fax transmission.

Hereinafter, the operation of FIG. 1 will be briefly described.

The user sets whether to enter vocoder mode or data mode when initially setting up. In this case, if the vocoder mode is set, the mobile station 10 transmits packet data (voice data, etc.) to the base station controller 20, and the PCM in the decoder 21b of the vocoder mode converts the packet data into PCM data so that the switching station ( 30).

If the user initially sets the data mode, the packet data transmitted from the mobile station is transmitted to the switching center 30 through the IWF 22.

In addition, the transmission from the switching center 30 to the mobile station 10 will proceed in the reverse order. That is, PCM data is converted into packet data by the base station controller 20 (BSC) and transmitted to the mobile station.

However, in the conventional wireless system as described above, switching from the vocoder mode to the data mode is impossible during a call.

Therefore, if the user sets the vocoder mode at the time of the first call setup, the user cannot change the data mode during the call and thus cannot provide the fax service as in the wired network.

Therefore, in order to solve the above problems, the present invention adds a fax signal detector that can detect a signal transmitted from an exchange station and change it to a data mode in the case of a facsimile signal, and from the vocoder mode to the data mode based on the detected signal. An apparatus and a control method including a control unit for controlling a switch to switch are provided.

1 is a block diagram of a vocoder mode for a conventional voice call and a separate data mode for fax transmission.

2 is a block diagram showing a vocoder mode for a voice call of the present invention and a data mode for fax transmission.

3 is a facsimile time procedure for explaining a process of detecting a fax signal in the fax signal detector.

4 is a flowchart illustrating an embodiment of detecting a fax signal of the present invention and switching from a vocoder mode to a data mode

The present invention comprises the steps of transmitting a signal at the switching center; Transmitting a signal at the called party; Determining whether the detected signal of the called party is a facsimile signal; As a result of the determination, the facsimile signal is switched to the data mode.

In addition, in the present invention, the called party signal is characterized in that the signal sent from the mobile station to the exchange.

In addition, the method for detecting a facsimile signal in the present invention is characterized by detecting by using a CED signal of the called party sent in phase A (A), which is a fax transmission step, or a preamble signal sent by the phase ratio (B).

In the present invention, the CED signal detection and the preamble signal detection for determining whether the facsimile signal is performed are characterized before the vocoder is executed.

In addition, in the present invention, the CED signal is composed of a continuous singleton, the detection is processed in units of samples or in units of frames, and the preamble signal is composed of FSK signals and must be made in units of samples. After receiving the PCM signal in units of samples, the FSK signal is detected.

In addition, the representative configuration apparatus of the present invention comprises a switching station for transmitting a signal to the base station controller; A mobile station for transmitting a called party signal; When the called signal (CED) is a facsimile signal, it characterized in that the base station controller including a switching unit for switching to the data processing unit, and a control unit for controlling the same.

Other objects and features of the present invention will become apparent from the detailed description of the embodiments with reference to the accompanying drawings.

Hereinafter, an apparatus and method for switching from a vocoder mode to a data mode according to the present invention will be described with reference to the accompanying drawings.

FIG. 2 is also similar to the conventional block in FIG.

That is, a mobile station 10 (MS, Mobile Station) including a facsimile, a telephone and a terminal, a base station controller 20 (BSC, Base Station Controller) for controlling a base station, and an exchange station 30 (MSC, Mobile Switching Center) It is composed of

A vocoder (21) for processing voice inside the base station controller (20); A switching unit for switching to the data processing unit 22 under control of the data processing unit 22 (IWF, Inter Working Function) for processing data and the control unit 24 when the signal transmitted from the mobile station 10 is a facsimile signal. It is comprised including 25.

Also, the vocoder has an encoder 21a for encrypting the PCM data transmitted from the switching center 30, a decoder 21b for decoding the packet data transmitted from the mobile station 10, and converts the input data into PCM data. PCM 21c is included.

Hereinafter, the operation of FIG. 2 will be described.

The user sets whether to enter vocoder mode or data mode when initially setting up. In this case, if the vocoder mode is set, the mobile station 10 transmits packet data (voice data, etc.) to the base station controller 20, and the PCM in the decoder 21b of the vocoder mode converts the packet data into PCM data so that the switching station ( 30).

If the user initially sets the data mode, the packet data transmitted from the mobile station is transmitted to the switching center 30 through the IWF 22.

In addition, the transmission from the switching center 30 to the mobile station 10 will proceed in the reverse order.

More specifically, assuming that the current mode is set to the vocode mode, the switching center 30 transmits a signal to the base station controller 20 and transmits the signal transmitted from the mobile station 10 to the fax signal detector 23. If the detected signal is a facsimile signal, the control unit 24 controls the switching unit 25 to switch to the data mode.

3 shows a facsimile time procedure for explaining the process of detecting a fax signal in the fax signal detector 23.

First of all, in order to provide a fax service in a vocoder system, a data mode for transmitting a fax is required, and a fax signal detection for switching from a vocoder mode to a data mode is essential.

Therefore, in order to realize the object of the present invention, whether or not the facsimile signal is switched to the fax mode by detecting the signal input from the mobile station 10 before the vocoder mode is executed using the PCM information converted by the decoder PCM. To decide.

3 will be described below.

According to the standard T.30, which is a step for facsimile transmission established by the International Telecommunication Union (ITU), as shown in the drawing, it is composed of five steps of phases A, B, C, D, and E. The detection of the fax signal to switch to the data mode of C should be performed before phase C.

Phase A is a call setup step, and the call setup can be performed in manual or automatic mode. In step A, the sender's fax (for example, the exchange side of the present invention) transmits CNG (Calling Tone), and the receiver's fax (for example, the mobile station side of the present invention) is the CED (recipient station identification). Send a signal.

Phase B is a message transmission preprocessing step, and processes prior information necessary for message transmission. In the step B, a preamble signal (for example, a function identification, a receivable condition check, a selection condition command, etc.) for the transmission status inspection is transmitted. Therefore, the detection of the fax signal in the present invention is performed by the CED signal sent in phase A, It detects using the preamble signal sent in phase B.

For reference, phase C is a message transmission procedure, phase D includes information after the message procedure, and phase E is a step of restoring a call to its original state.

Signal characteristics transmitted in each phase described above, and a process of detecting a fax signal using each signal will be described.

First, the CED (recipient station identification) signal transmitted in phase A is a process of detecting a fax signal as the signal sent first in the T-30, the ITU-T standard, to determine whether the current fax is used.

The CED signal is 2100 Hz Since it consists of a continuous singleton between 2.6 and 4.0 seconds with a frequency of 15 Hz, the CED detection should be performed before the vocoder is executed, and can be processed sample by sample or frame by frame.

Secondly, since the preamble signal transmitted and received in phase B is a signal selectively transmitted according to the facsimile mode according to T-30, which is a standard of ITU-T, the facsimile has not been transmitted in phase A. Or, it is a process of detecting whether the facsimile is detected by detecting a preamble signal transmitted in the call time sequence of the facsimile even when the CED signal is transmitted but not detected in phase A.

Since the preamble signal is composed of an FSK signal that is transmitted at 300bps of 0 * fe continuously for about 1 second, the detection of the FSK signal must also be performed before the vocoder is executed and must be made in units of samples. After receiving the PCM signal in sample units, the FSK signal should be detected.

Thirdly, after the facsimile signal is detected, the facsimile signal is detected by the facsimile signal detector in phases A and B, and the switching unit operates the signal from the vocoder mode to the data mode.

4 is a flowchart illustrating an embodiment of detecting a fax signal of the present invention and switching from a vocoder mode to a data mode.

The fax signal detector 23 detects the called party's signal. (Step 40).

If the detection result is the CED signal of the phase A or the preamble signal of the phase B described above, the control unit 24 controls the switching unit 25 to switch from the vocoder mode to the data mode, and if the signal detection result is not the facsimile signal, The conventional vocoder mode is continued. (Steps 41, 42, 43).

As described above, in the present invention, the signal transmitted from the called party is detected and the facsimile signal is switched from the vocoder mode to the data mode.

Although the preferred embodiment of the present invention has been described above, the present invention may use various changes, modifications, and equivalents. It is clear that the present invention can be applied in the same manner by appropriately modifying the above embodiments.

Accordingly, the above description does not limit the scope of the invention as defined by the limitations of the following claims.

The present invention solves many difficulties in transmitting a facsimile during a call in a system using a vocoder, and solves a lot of difficulties in transmitting a facsimile during a call. By switching to, it is possible to transfer data using a facsimile during a call. Therefore, there is an effect that can provide the same service as a wired network in a wireless system.

Claims (5)

In the base station controller of the mobile communication system, Transmitting a signal at the switching center; Transmitting a signal at the called party; Determining whether the detected signal of the called party is a facsimile signal; And a method for switching to a data mode in a system using a vocoder, wherein the system switches to a data mode when a facsimile signal is determined. The method of claim 1, wherein the method for detecting a facsimile signal comprises detecting a vocoder using a CED signal of a called party sent in phase A (A), which is a fax transmission step, or a preamble signal sent in a phase ratio (B). How to switch to data mode on your system. The method according to claim 2, wherein the CED signal detection and the preamble signal detection for determining whether the facsimile signal is performed are performed before the vocoder is executed. The method of claim 2, wherein the CED signal is composed of continuous singletons, the detection is processed in units of samples or in units of frames, and the preamble signal is composed of FSK signals and must be in units of samples. A method of switching to a data mode in a system using a vocoder, characterized in that an FSK signal is detected after receiving a PCM signal in sample units when a lump occurs. In a system provided with a mobile station, a base station controller, and a switching station, An exchange station for transmitting a signal to the base station controller; A mobile station for transmitting a called party signal; And a base station controller including a switching unit for switching to a data processing unit and a control unit for controlling the same when the called signal (CED) is a facsimile signal.