KR100447391B1 - method for automatically adjusting a receiving signal of the ADSL modem - Google Patents

Abstract

The present invention relates to a method for adjusting a reception signal of an ADSL modem apparatus, comprising: a reception signal detection confirmation step of initializing an ADSL modem and detecting whether a received signal symbol transmitted from a subscriber device is detected; and performing the initial gain control step; When the received signal is detected in the signal detection confirmation step, the gain of the call connection and the input signal are adjusted. The AGC gain fixing step of setting the currently set AGC gain value, and the input of the received signal when the received signal is small enough not to be detected. AGC gain adjustment step of increasing and compensating the level by a specific level value, optimum gain judgment step of judging whether the current received signal gain is greater than the set optimal gain level value after AGC gain adjustment step, and the result of judging at the optimum gain judgment step If the received signal gain is not greater than the set optimal gain level, repeat the AGC gain adjustment step. The AGC gain re-adjustment step and an optimum gain setting step of setting the current received signal gain value to maintain the present condition when the current received signal gain is greater than the set optimum gain level as determined during the optimum gain determination step.

The present invention adjusts the received signal to an appropriate level from the initial stage of the Hoshi illustration between the ADSL modem and the subscriber device, so that it can be accurately received, thereby preventing the malfunction of the ADSL modem due to the weakness of the received signal, and of course, without additional circuit configuration. The adjustment function is easily implemented, thus significantly improving the functionality of the ADSL modem device.

Description

Method for automatically adjusting a receiving signal of the ADSL modem}

The present invention relates to a method for automatically adjusting a received signal of an SDL modem apparatus, and more particularly, by adjusting the detection level of a received signal to an appropriate level by using an AGC from an initial stage when a call attempt is made between an ADSL modem and a subscriber device. Therefore, the present invention relates to a method for automatically adjusting a received signal of a DSL modem device to prevent a malfunction of an ADSL modem due to a weak reception signal.

In general, Asymmetric Digital Subscriber Line (ADSL) systems are designed to provide high-speed digital services such as high-speed Internet and online access without interfering with analog telephone service (POTS) on existing twisted pair copper networks. Refers to a service system provided to telephone subscribers such as telecommuting and Video On Demand (VOD). In general, the ADSL line coding method uses a discrete multi-tone (DMT) and a carrierless AM / PM (CAP) method. The ADSL DMT has an asymmetric bandwidth characteristic of 64-640 kbit / s upstream. For downstream, it supports 8 Mbit / s at 500 kbit / s. Thus, such an ADSL system has good characteristics for downloading large files containing graphics from media such as the Internet.

In addition, the ADSL system as described above typically includes a DSLAM (xDSL Access Multiplexer; 70) device, which is typically an ADSL modem card 72 that modulates and demodulates a communication signal input and output through a communication line 71. And a data processing unit 73 which is connected to the ADSL modem card 72 and is a management entity that processes data call signals.

As shown in FIG. 2, the ADSL modem card 72 has a reception signal processing block 74 for receiving and transmitting a call signal of a subscriber to an external subscriber and a function of the reception signal processing block 74. To detect the data signal received from the transmission signal processing block 75 and the subscriber device (76A-N) and transmits the data to the subscriber device (76A-N) to transmit the call signal input from the external subscriber to the subscriber A hybrid unit 77 is provided, wherein the received signal processing block 74 has an AGC (Auto gain) for automatically adjusting the signal gain of the received signal of the subscriber device 76A-N detected through the hybrid unit 77. control: 78, an A / D converter 79 for converting the analog output signal of the AGC 78 into a digital signal, and a digital reception signal output from the A / D converter 79 as a signal in the frequency domain. Converted to output Digital signal processor (DSP) for fast-connecting the signal received from the FFT (80) and the received signal input from the FFT (80) by connecting a predetermined signal and determining a data transmission amount suitable for the line characteristics by measuring the quality of the line; ).

Meanwhile, referring to the operation of the reception signal block of the conventional ADSL modem apparatus as described above, when a signal for call connection is sent from any subscriber device 76A-N connected to a plurality of ADSL modems 72, this signal is transmitted. Is detected by the hybrid unit 77 and input to the AGC 78. At this time, the AGC 78 inputs the A / D converter 79 as it is without compensating the signal gain of the subscriber device 76A-N in the initial stage for call connection. The A / D converter 79 converts the received received signal into a digital signal and inputs it to the FFT 80. Then, the FFT 80 converts the received signal of the time domain into a signal of the frequency domain and inputs it to the DSP 81. Accordingly, the DSP 81 exchanges the basic information with the subscriber device by, for example, a handshake process (or ACKnowledge & ACTivation) for call connection in the initializing step of the received signal input through the above process. The DSP 81 executes the AGC function as a training process after the initialization step of executing the handshake process, and trains the ECHO CANCELLER, the timing and the frequency equalizer function. That is, the DSP 81 executes the function of the AGC 6 only after the initialization step. At this time, the AGC 78 executes the automatic gain adjustment function in the second step after the initialization step. It automatically adjusts the gain of received signal level. In addition, after the second training step, the DSP 81 performs an analysis process in the third step to analyze the state of the telephone line of the corresponding channel, and check the distance and the transmission speed and take appropriate measures. Then, the DSP 81 executes an exchange process as a final step after the analyzing step, sets the data rate, and notifies the corresponding subscriber device 76A-N to actually execute the data transfer. On the other hand, when a call signal is input from the external exchange 82 to the data processing unit 73 of the ADSL modem 72 of the DSLAM system 70, the data processing unit 73 processes the input call signal as a predetermined signal. The transmission is then transmitted to the corresponding subscriber device 76A-N via the transmission signal processing block 75 and the hybrid unit 77 to execute communication.

However, the reception signal processing block 74 of the conventional ADSL modem apparatus as described above is limited because the maximum voltage at which the subscriber device 76A-N can transmit data signals to the ADSL modem apparatus 72 through the transmission line is limited. When the device 76A-N is far from the transmission system, it is very weakly received by the received signal processing block 74 of the ADSL modem 72. However, since the received signal processing block 74 of the ADSL modem apparatus does not operate the AGC 78 in the first initialization step for call connection, if the received signal is weak, it cannot properly correct the signal level. There was a problem that the ADSL modem device malfunctioned because it was unable to determine whether the received signal was a noise or a normal signal.

Accordingly, the present invention has been invented to solve the above-described general problems. The subscriber signal is controlled by the DSP using the AGC from the initial stage when a call attempt between the ADSL modem and the subscriber device is made to an appropriate level. Therefore, the purpose of the present invention is to provide a method for automatically adjusting a received signal of an DSL modem device to prevent a malfunction of the ADSL modem due to a weak reception signal.

Another object of the present invention is to provide a method for automatically adjusting a received signal of an ADSL modem apparatus by easily executing a received signal adjusting function.

In order to achieve the above object, the present invention provides a method for adjusting a reception signal of an ADSL modem apparatus, comprising: a reception signal detection confirmation step of initializing an ADSL modem and detecting whether an input of a reception signal symbol transmitted from a subscriber device is detected; In the initial gain control step, when the received signal is detected in the received signal detection confirmation step, the gain of the call connection and the input signal is adjusted, and the AGC gain fixing step of setting the currently set AGC gain value and the received signal are not detected. If it is small enough, the AGC gain adjusting step of compensating by increasing the input level of the received signal by a specific level value, and the optimum gain determining step of determining whether the current received signal gain is greater than the set optimal gain level value after the AGC gain adjusting step; In the optimal gain determination stage, the current received signal gain is not greater than the set optimal gain level. In the case of the AGC gain re-adjustment step of repeatedly performing the AGC gain adjustment step and the optimum gain determination step, if the current received signal gain is greater than the set optimum gain level, the current received signal gain value is set to maintain the present condition. It provides a method for automatically adjusting the received signal of the DSL modem device comprising the step of setting the optimum gain.

1 is a block diagram illustrating a received signal processing method of a conventional ADSL modem.

2 is an explanatory diagram illustrating an ADSL modem apparatus to which the method of the present invention is applied.

3 is a flow chart of the present invention.

4 is a flowchart for explaining a received signal gain control method of the present invention.

<Detailed Description of Codes>

1: ADSL Modem Device 2: Reception Signal Processing Block

3: transmission signal processing block 4: subscriber equipment

5: hybrid part 6: AGC

7: A / D Converter 8: FFT

9: DSP 10: Timer

11: data processing unit 12: control processor

13: memory 14: exchanger

15: communication line

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

The ADSL modem apparatus 1 of the DSLAM system 50 to which the present invention is applied includes a reception signal processing block 2 for receiving a call signal of a subscriber and transmitting it to an external subscriber as shown in FIG. Contrary to the function of (2), it detects the data signal received from the transmission signal processing block 3 and the subscriber equipment 4A-N which transmits the call signal input from the external subscriber to the subscriber or the subscriber equipment 4A. -N) is provided with a hybrid unit 5 for transmitting data,

At this time, the received signal processing block 2 includes an AGC 6 which automatically adjusts the signal gain of the received signal of the subscriber device 4A-N detected through the hybrid unit 5 from the initial stage, and the AGC 6 An A / D converter 7 for converting an analog output signal of a digital signal into a digital signal, an FFT 8 for converting a digital received signal output from the A / D converter 7 into a signal in a frequency domain, and For example, if the number of symbols of the received signal input through the FFT (8) is normal, 128 inputs are judged to control the function of the AGC (6) from the initializing step for call connection and measuring the quality of the line The upper layer including the DSP 9 for determining a data transfer amount suitable for the characteristic, a timer 10 for executing time counting according to the time control of the DSP 9, and a function control of the DSP 9; The operation is performed in accordance with the operation command control signal input from the data processing unit 11. A control processor 12 for controlling, and a memory 13 for storing the work data performed by the control processor 12.

Next timeWow The method of the present invention applied to the same system will be described.

As shown in FIG. 3, the present invention initializes the ADSL modem by the system initialization process (S1) and then proceeds to the reception signal input determination process (S2) to determine whether a signal is currently input from the subscriber device. When the reception signal is not input from the subscriber device as a result of the determination during the reception signal input determination process (S2), it is determined whether the reception signal input again after waiting for a predetermined time.

However, if the reception signal is detected from the subscriber device as a result of the determination during the reception signal input determination process (S2), the process proceeds to the initial gain control execution process (S3) to execute the initialization process for call connection and simultaneously through the AGC. Automatically adjust the gain of the input signal to improve signal detection.

That is, when the initial gain control execution process is described in more detail with reference to FIG. 4, when the reception signal is detected from the current subscriber device in the reception signal detection determination step S31, the process proceeds to the AGC gain fixing step S32. Set the AGC gain value. However, if it is determined that the received signal is not detected from the subscriber device as a result of the reception signal detection step S31, the process proceeds to the AGC gain adjustment step S33, whereby the input level of the received signal is set to a specific level value, for example, 1 dB. Reward by increasing In addition, after the AGC gain adjusting step S33, the process proceeds to the optimum gain determining step S34 to determine whether the current received signal gain is greater than the set optimum gain level, for example, 6 dB. At this time, if it is determined during the optimum gain determining step S34 that the current received signal gain is not greater than the set optimal gain level, the process returns to the previous step S31 and repeats the loop.

However, if it is determined during the optimum gain determining step S34 that the current received signal gain is greater than the set optimal gain level, the process proceeds to the optimum gain setting step S35 and the current received signal gain value is set to "0". Next, return to the previous step (S31) and repeat the loop.

In other words, when a signal for call connection is transmitted through the communication line 15 from any of the subscriber devices 4A-N connected to the ADSL modem 1, the signal is detected by the hybrid unit 5. And input to the AGC 6. Then, the AGC 6 inputs the received signal of the corresponding subscriber device 4A-N for call connection to the A / D converter 7. The A / D converter 7 converts the received signal into a digital signal and inputs it to the FFT 8. In addition, the FFT 8 converts the received signal of the time domain into a signal of the frequency domain and inputs it to the DSP 9.

Then, the DSP 9 determines whether a symbol, for example, 128 symbols, of the received signal input through the above process is input, and initializes, for example, a subscriber by a handshake process (or ACKnowledge & ACTivation) for call connection. The DSP 9 controls the AGC 6 from this initialization process so that the received signal of the subscriber device 4A-N currently received is appropriately received, for example. The gain is adjusted every predetermined time using the timer 10 until it becomes 6 dB or more.

That is, the AGC 6 increases the signal by 1dB until the received signal level of the subscriber device 4A-N to be input is 6dB or more, and transmits it to the A / D converter 7.

Therefore, the DSP 9 obtains an optimal received signal by the initialization process as described above, and thus executes an accurate handshake process.

On the other hand, after the initial gain control execution process (S3) proceeds to the training process (S4) to train the echo canceller (ECHO CANCELLER), time and equalization (Timing and Frequency Equalizer) function. In addition, after the training process (S4) and proceeds to the channel analysis step (S5) to analyze the state of the channel currently desired call connection. After the channel analysis step S5, the data transmission step S6 is performed to transmit the information determined by the step S5, for example, a data transmission rate or a transmission rate, to the subscriber device and the corresponding data based on the determined information. Transmit.

In other words, the DSP 9 performs an analysis process in the third step after the training process, analyzes the state of the telephone line of the corresponding channel, checks the distance and the transmission speed, and takes appropriate measures. Then, the DSP 9 executes an exchange process as a final step after the analysis process, sets a data rate, and notifies the corresponding subscriber device 4A-N to actually execute the data transfer.

On the other hand, when a call signal is input from the external exchange 14 to the data processing unit 11 of the ADSL modem 1 of the DSLAM system 50, the data processing unit 11 processes the input call signal as a predetermined signal. Then, the transmission signal processing block 2 and the hybrid unit 5 are transmitted to the corresponding subscriber device 4A-N to execute communication.

Therefore, according to the present invention, since the DSP 9 controls the AGC 6 from the initialization process, the subscriber device 4A-N adjusts the received signal from the subscriber device 4A-N to an optimal level. Even if the distance from the system of the present invention is far apart, the reception signal of the subscriber equipment 4A-N can be normally received.

As described above, according to the present invention, since the DSP adjusts the detection level of the received signal to an appropriate level from the initial stage when the ADSL modem and the subscriber device attempt the call, the subscriber signal can be accurately received, and thus the received signal is accordingly. It has the advantage of preventing malfunction of ADSL modem due to the weakness.

In addition, according to the present invention, the reception signal adjustment function can be easily executed to significantly improve the functionality of the ADSL modem apparatus.

Claims (3)

In the received signal adjusting method of the ADSL modem apparatus, A reception signal detection confirmation step of initializing the ADSL modem and detecting whether or not the reception signal symbol transmitted from the subscriber device is input; An AGC gain fixing step of adjusting a gain of a call connection and an input signal when the reception signal is detected in the reception signal detection confirmation step as an initial gain control execution step, and setting a currently set AGC gain value; An AGC gain adjusting step of compensating by increasing the input level of the received signal by a specific level when the received signal is small enough not to be detected; An optimum gain determining step of determining whether a current received signal gain is greater than a set optimum gain level value after the AGC gain adjusting step; An AGC gain re-adjustment step of repeatedly performing the AGC gain adjustment step if the current received signal gain is not greater than the set optimum gain level as determined during the optimum gain determination step; And determining the optimum gain level if the current received signal gain is greater than the set optimal gain level. The optimal gain setting step of setting the current received signal gain value to maintain the current status. Receiving signal automatic control method. delete The method of claim 1, wherein the specific level value during the AGC gain adjustment step is 1 dB, and the optimum gain level value during the optimum gain determination step is 6 dB.