KR100443007B1 - Apparatus and method for detecting MODEM initialization signal from asynchronous digital subscriber line - Google Patents

Abstract

The present invention is asymmetric digital subscriber line modem that minimizes the power consumption in the standby state of the modem chip by determining the presence of a single wave transmitted from the remote terminal when implementing the DMT ADSL central station modem chip In order to provide an initial signal detecting apparatus and a method thereof, the apparatus includes a central station for receiving a signal transmitted from a remote terminal of an ADSL network, depending on the degree of change in the voltage level of the signal transmitted from the remote terminal. And a voltage determiner for generating an enable signal and a signal determiner for determining whether to initiate the initialization of the modem chip by comparing / determining a frequency of a signal transmitted from a remote terminal activated by the enable signal of the voltage determiner. The voltage judging unit causes voltage fluctuations above a certain level when the input signal from the subscriber line By activating only the signal determination parts of the case thereby reducing the power consumption of the central office modem in a wait state.

Description

Apparatus and method for detecting MODEM initialization signal from asynchronous digital subscriber line}

The present invention relates to the detection of an initial signal of an asymmetric digital subscriber line (ADSL) modem (MODEM), and more particularly, to a DMT (Discrete Multi Tone) ADSL central office (CO) modem. The present invention relates to an initial signal detecting apparatus and method for an asymmetric digital subscriber line modem for determining the presence of a single wave transmitted from a remote terminal (RT) or a real time chip when the chip is implemented. .

In general, xDSL (x = A, H, S, V, etc.) expands the potential bandwidth as much as possible through a pair of copper wires, allowing plain old telephony service (POTS) services without interference on lines within the same pipeline. Rather, it enables POTS services simultaneously on xDSL transmission lines.

DMT technology is a multi-carrier transmission method, which is considered to be stronger in noise and better compression rate than CAP technology, and is applied as ADSL line coding technology standard. ADSL uses existing subscriber line as it is and provides data at relatively low cost because ADSL and analog POTS use the same line.

1 is a block diagram of a general DMT modulation scheme ADSL system.

According to Fig. 1, the ADSL system includes a modulation transmitter for modulating a transmission target signal and transmitting it to a subscriber line and a demodulation receiver for receiving a signal transmitted through a subscriber line. Here, (a) is a block diagram of a modulation transmitter, and (b) is a block diagram of a demodulation receiver.

The modulation transmitter is to modulate the output of the interleaver in a certain process and transmit it through the channel, and the demodulation receiver is to demodulate the signal received from the channel and apply it to the deinterleaver.

The modulation transmitter includes a tone ordering unit 111, an encoding unit 112, an inverse fast fourier transform (IFFT) 113, a cyclic prefix insert unit 114, and a parallel-serial conversion unit. And 115.

The demodulation receiver is symmetrical in its signal processing with respect to the modulation transmitter. Thus, the demodulation receiver includes a TEQ (121), a parallel-to-serial converter (121), a cyclic prefix insert (123), a fast fourier transform (FFT) 124, and a frequency equalization (FEQ) 125. And a decoder 126 and a tone deordering unit 127.

The modulation transmitter and the demodulator receiver perform modulation and demodulation according to the DMT scheme, and this function can be implemented by using a properly designed chip. Thus, the central station CO of the ADSL network initializes the CO-modem chip based on the signal received from the remote terminal RT, and then performs demodulation of the DMT scheme.

2 shows an initialization block of a DMT modulation ADSL modem according to the prior art, and FIG. 3 shows a flowchart of an initialization method of the DMT modulation ADSL modem according to the prior art.

According to FIG. 2, a signal transmission is performed between the remote terminal 210 and the central station 220 in connection with the modem chip initialization of the central station 220. The central station 220 monitors the line connected to the remote terminal 210 to confirm whether a single wave is transmitted.

The single wave transmitted from the remote terminal 210 to the central station 220 is detected by the signal determination unit 221 provided in the central station 220 and serves as a reference for determining whether to initiate the initialization of the corresponding modem chip. The signal determination unit 221 performs a function of determining whether a signal exists in a line.

According to FIG. 3, the modem chip of the central station 220 is in an admitted state until the initialization of the DMT ADSL modem is performed (S310).

The central station 220 waits in an idle state while monitoring a subscriber line and initiates initialization by detecting a specific signal transmitted from the remote terminal 210 side connected to the corresponding line. The signal used as the basis of this initialization existence determination is transmitted as a single wave.

In order to initiate the initialization, the central station 220 determines whether the signal transmitted from the remote terminal 210 conforms to the initialization protocol (S320).

The initialization protocol of the ADSL modem chip is as described in IEEE 994.1.

In order to determine whether the protocol conforms to the initialization protocol, the signal determination unit 221 performs fast Fourier transform (FFT) on the received signal to compare / determine the amplitude of the desired frequency and the amplitude of the surrounding frequency. .

If it is determined that the input signal is a signal suitable for the protocol through comparison of the frequency amplitude, the initialization of the corresponding modem chip is performed (S330).

On the other hand, if it is determined that the input signal does not comply with the protocol, the process returns to step S310 and the corresponding modem chip maintains the standby state.

In this way, the central station compares the signals input to the line in the standby state by performing Fourier transform, and then determines that a signal of a specific frequency is sent from the remote terminal 210 to perform the following initialization process.

That is, in the prior art, there was no part for initiating initialization.

Therefore, in order to start the initialization, the signal determination unit having the Fourier transform function monitors the subscriber line, and after confirming the occurrence of the amplitude of a specific frequency, it is necessary to judge the start of the initialization. There was a disadvantage.

The present invention was created to solve the above-mentioned conventional problems, and an object of the present invention is to initialize the modem chip after determining the existence of a single wave transmitted from the remote terminal when the DMT ADSL central station modem chip is implemented. It is to provide an initial signal detection device of the asymmetric digital subscriber line modem to minimize the power consumption in the standby state of the modem chip.

It is another object of the present invention to selectively drive the signal determination unit only when the voltage level of the subscriber line in the central station of the ADSL network changes by more than a certain level, thereby reducing the power consumption in the standby state of the central station modem chip. An initial signal detection method of a subscriber line modem is provided.

1 is a block diagram of a typical DMT modulation ADSL system.

2 is an initialization block diagram of a DMT modulation scheme ADSL modem according to the prior art.

Figure 3 is a flow chart of the initialization method of the DMT modulation scheme ADSL modem according to the prior art.

Figure 4 is a block diagram of the initial signal detection apparatus of the asymmetric digital subscriber line modem according to an embodiment of the present invention.

5 is a flowchart of a method for detecting an initial signal of an asymmetric digital subscriber line modem in accordance with an embodiment of the present invention.

Explanation of symbols on the main parts of the drawings

410: remote terminal 420: central station

430: voltage determining unit 440: signal determining unit

The initial signal detection apparatus of the asymmetric digital subscriber line modem of the present invention for achieving the above object, the central station receiving a signal transmitted from a remote terminal of the ADSL network, the degree of change in the voltage level of the signal transmitted from the remote terminal A voltage determiner for generating an enable signal according to the present invention; And a signal determination unit for determining whether to initiate the initialization of the modem chip by comparing / determining a frequency of a signal activated by the enable signal of the voltage determination unit and transmitted from the remote terminal.

In addition, the initial signal detection method of the asymmetric digital subscriber line modem of the present invention comprises the steps of: generating an enable signal when the voltage of the signal input through the subscriber line in the central station of the ADSL network fluctuates more than a set level; And when the enable signal is generated, determining whether to initiate the initialization process of the central station modem chip by detecting a signal input through the subscriber line.

In the case where it is determined whether to initiate initialization based on the enable signal, when the enable signal is generated, Fourier transforms a signal input through a subscriber line in a set manner, and sets the amplitude and the surrounding frequency of the set frequency among the converted signals. By comparing the amplitudes of the signals, it is possible to determine whether to initiate the initialization process of the central station modem chip according to whether the corresponding signal conforms to a specific protocol.

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

4 is a block diagram of an initial signal detection apparatus of an asymmetric digital subscriber line modem according to an embodiment of the present invention, and FIG. 5 is a flowchart of an initial signal detection method of an asymmetric digital subscriber line modem according to an embodiment of the present invention.

According to Figure 4, this embodiment is applied to the ADSL network of the DMT scheme.

In connection with the initialization of the central station ADSL modem chip of the DMT scheme, a single wave is transmitted between the remote terminal 410 and the central station 420 connected to the subscriber line. Central station 420 includes a modem chip (not shown) having a function for demodulating signals over subscriber lines.

In addition, the central station 420 includes a voltage determination unit 430 for detecting a voltage change of an input signal, and a signal determination unit 440 for Fourier transforming a signal received from a subscriber line to compare frequency amplitude.

The voltage determiner 430 applies an enable signal to a signal line connected to the signal determiner 440 when an input signal received through a subscriber line to which the remote terminal 410 is connected exceeds a set voltage level.

The enable signal activates a Fourier transform and frequency determination function of the signal determination unit 440. That is, the signal determination unit 440 starts the frequency determination only by the enable signal of the voltage determination unit 430. When it is determined that the initialization is started through the frequency determination, the modem chip initialization in the central station 420 is performed.

As such, the voltage determination unit 430 first determines the voltage level of the subscriber line, and activates the signal determination unit 440 only when the voltage level becomes higher than a predetermined level, thereby consuming power by the modem chip in the standby state. Can be reduced.

5, in the initial signal detection method according to the present invention, the central station modem chip monitors the subscriber line in the standby state. Here, the monitoring of the subscriber line is performed by the voltage determination unit (S510).

The voltage determination unit monitors the subscriber line and determines whether a voltage change of a predetermined level or more occurs (S520).

The subscriber line differs in its voltage level when a single wave is received from a remote terminal and when it is not. In some transmission lines, noise may be inserted. Therefore, it is preferable that the comparison reference for detecting the change in the voltage level in the voltage determination unit is set to a voltage change value corresponding to the reception of the single wave from the remote terminal.

Since the voltage determination unit does not output the enable signal while the subscriber line maintains the voltage below the set level, the modem chip maintains the standby state in step S510.

On the other hand, if it is determined that the voltage variation over the set level is determined, the voltage determination unit generates an enable signal. The generated enable signal is transmitted to the signal determination unit to activate the frequency comparison function.

The signal determination unit is in a standby state until the enable signal is applied. In the standby state, the signal determiner does not perform the Fourier transform and frequency comparison functions, thereby reducing power consumption.

When enabled by the enable signal, the signal determiner performs fast Fourier transform on the input signal of the subscriber line according to the FFT function and compares the amplitude of the desired frequency with the amplitude of the frequency around the modem chip to initialize the modem chip. It is determined whether to start (S530).

Whether or not to initiate initialization of the modem chip is determined based on the initialization protocol specified in IEEE 994.1. If it is determined that the modem chip is not suitable for initiation of initialization based on the initialization protocol, the signal determination unit releases the active state and returns to step S510 to be in the standby state. Therefore, in this case, the signal determination unit will be activated again when the voltage determination unit detects the voltage level of the subscriber line again and applies the enable signal accordingly.

If it is determined in step S530 to start the initialization process of the modem chip is initialized for the modem chip of the central station. Since the initialization is performed, the modulation and demodulation of the DMT method for the signal exchanged between the remote terminal and the modem of the central station through the subscriber line can be performed (S540).

The embodiments described above are within the scope of various changes, modifications, and equivalents of the present invention. Therefore, the present invention is not limited to the description of the examples.

According to the initial signal detection apparatus and method thereof of the asymmetric digital subscriber line modem of the present invention, the voltage determination unit input signal from the subscriber line, compared to the prior art in which the signal determination unit continuously monitors the subscriber line when the central station modem is in the standby state. By activating the signal determination unit only when the voltage fluctuation occurs above a certain level, there is an effect of reducing the power consumption of the central station modem in the standby state.

Claims (3)

The central station receiving the signal transmitted from the remote terminal of the ADSL network, A voltage determination unit which receives an transmitted signal transmitted from a remote terminal and generates an enable signal according to a degree of change in the voltage level of the signal; And a signal determiner configured to determine whether to initiate the initialization of a modem chip by comparing / determining a frequency of a signal transmitted from the remote terminal by activation of the enable signal. Receiving, by a voltage determining unit, a signal input through a subscriber line from a central station of an ADSL network; Generating an enable signal when the voltage of the received signal varies above a set level; When the generated enable signal is applied, activating a signal determination unit maintaining a standby state; The activated signal determination unit comprises the step of comparing / determining the frequency of the signal input through the subscriber line to determine whether to initiate the initialization of the central station modem chip, the initial signal detection method of the asymmetric digital subscriber line modem. The method of claim 2, Determination result of initializing start, If it is determined to start, the initialization of the central station modem chip is performed, If it is determined that it will not be initiated, the method of canceling the activation state of the signal determining unit to return to the standby state further comprises the step of performing the initial signal detection method of the asymmetric digital subscriber line modem.