KR100492948B1 - Multi carrier digital subscriber line system, spectrum management method of the same and central office apparatus - Google Patents

Abstract

The present invention relates to a multi-carrier digital subscriber line (hereinafter referred to as MC DSL) system, a spectrum management method and a base station apparatus of the system.

The present invention provides a method of measuring channel information of lines included in a binder, collecting the measured channel information, and using the collected channel information to determine the number of bits allocated to subchannels of at least one of the lines. Determine a subchannel having a minimum cost function that is a sum of a function of power increase and decrease of a subchannel of the one line and a function of reduction of the maximum allowable allocation bit number of the subchannel of at least one of the remaining lines. Determining the number of allocated bits by adding the number of bits, and performing communication by allocating bits to each subchannel of the lines according to the determined number of allocated bits and power. Provide a method. It also provides an MC DSL system and a base station apparatus.

The spectrum management method of the multi-carrier digital subscriber line system and the base station apparatus used in the present invention have a high performance while having a small amount of calculation.

Description

MULTI CARRIER DIGITAL SUBSCRIBER LINE SYSTEM, SPECTRUM MANAGEMENT METHOD OF THE SAME AND CENTRAL OFFICE APPARATUS

The present invention relates to a multi-carrier digital subscriber line (hereinafter referred to as MC DSL) system, a spectrum management method and a base station apparatus of the system.

Recently, there has been an increase in demand for multimedia services through telecommunication networks, and digital subscribers to provide data transfer rates from hundreds of kbps to tens of Mbps using existing copper telephone lines without amplifiers or repeaters to meet these demands. line method has been developed. DSLs have evolved into various forms such as high-data-rate DSL (HDSL), single-line HDSL (SDSL), asymmetry DSL (ADSL), universal ADSL (UDASL), and very high-data rate DSL (VDSL). These DSLs can be classified into single-carrier (hereinafter referred to as SC) DSL and multi-carrier (hereinafter referred to as MC) DSL according to the modulation and demodulation scheme used. Among these, MC DSL is a method of dividing a frequency band used for transmission and reception into a plurality of subchannels, and typically includes a DSL of a DMT method.

The MC DSL system is degraded by crosstalk interference between lines located in a binder including a plurality of lines. In particular, in the prior art DSL system using the static spectrum, since the interference between the lines is not taken into account, as the subscriber line in one binder increases, its performance rapidly decreases due to crosstalk interference. Dynamic spectrum management (DSM) technology has been developed to solve these problems and maximize the performance of DSL systems. Dynamic spectrum management technology is a technique for determining the transmission power mask of a subscriber line as a function of the environment of the subscriber line belonging to the same binder, that is, the line attenuation, the magnitude of the crosstalk signal, and the background noise. Conventional dynamic spectrum management techniques include flat power cutback (FPCB) technology, iterative waterfilling (IWF) technology, and optimal spectrum balancing (OSB). ) Technology. These technologies are "JM Cioffi, Dynamic Spectrum Management Report, T1E1.4 / 2003-018R" and "Wei Yu, George Ginis, and John M. Cioffi, Distributed Multiuser Power Control for Digital Subscriber Lines, IEEE JSAC, Jun. 2002" Well explained. Among these, FPCB is a technique of uniformly reducing the transmission power of a line with low attenuation regardless of the tone position, and increasing the transmission power of a line with high attenuation. IWF is a technique in which systems of subscriber lines belonging to the same binder independently repeat bit loading based on water filling to reach an equilibrium state to derive a bit table and a power table suitable for a given line environment. The OSB defines a cost function that consists of the transmit power and allocated bits per ton of subscriber lines belonging to the same binder, and obtains the transmit power and allocated bits of each tone through an exhaustive search that minimizes this cost function. Technology.

1 is a graph illustrating the rate region of dynamic spectrum management techniques. Here, the speed range means the entire range of transmission rate combinations that can be obtained by each user. The wider the speed range, the better the performance. Referring to FIG. 1, when the data rate of the first user User1 connected to the base station through the first line has a predetermined value, the second user User2 connected to the base station through the second line The transmission rate of is the OSB technology is the largest, IWF technology is the next, FPCB technology is the worst. In addition, when the transmission rate of the second user User2 has a predetermined value, the transmission rate of the first user User1 has the largest OSB technology, the next IWF technology, and the lowest FPCB technology. As described above, the FPCB technology and the IWF technology have a problem in that the performance improvement is not so large as compared with the case of the OSB technology. On the contrary, the OSB technology is superior in performance to the FPCB technology and the IWF technology. However, the OSB technology has a disadvantage in that the time required for finding the optimal number of allocated bits is long because the operation is complicated.

Accordingly, an object of the present invention is to solve the above problems, to provide an improved performance of the MC DSL system, the spectrum management method and base station apparatus of the system.

It is also an object of the present invention to provide an MC DSL system with a simple operation required to find an optimal number of allocated bits, a spectrum management method of the system, and a base station apparatus.

As a technical means for achieving the above object, a first aspect of the present invention is to measure the channel information of the lines included in the binder, collecting the measured channel information, using the collected channel information Determine the number of allocated bits of the subchannels of at least one of the lines, the function of increasing or decreasing the power of the subchannels of the one line and the maximum allowed number of allocated bits of the subchannels of at least one of the remaining lines Determining the number of allocated bits by adding the number of allocated bits to the subchannel whose cost function is the sum of the functions for reduction, and allocating bits to each subchannel of the lines according to the determined number of allocated bits and power. It provides a spectrum management method of the MC DSL system comprising the step of performing communication.

The second aspect of the present invention is to measure the channel information of the lines included in the binder, collecting the measured channel information, by using the collected channel information of the sub-channel of at least one of the lines Determine a number of allocation bits, the cost function being the sum of a function of increasing or decreasing the power of the subchannels of the one line and a function of decreasing the maximum allowed allocation bits of the subchannels of at least one of the remaining lines Determining the number of allocated bits by adding an allocated number of bits to a subchannel, and transferring the determined allocated power to the modems connected to the lines as a maximum power mask, the modems being within the range of the maximum power mask. In the present invention, there is provided a spectrum management method of an MC DSL system, which includes performing a communication by allocating a bit to each subchannel.

A third aspect of the present invention includes a plurality of base station-side modems each connected to a plurality of lines located in one binder, and a spectrum management unit for determining the number of allocated bits and power of each subchannel of the plurality of lines. Is used to determine the number of bits allocated to the subchannels of at least one of the lines using the collected channel information, the function of the power increase and decrease of the subchannels of the one line and at least one of the remaining lines Provided is an MC DSL base station apparatus for determining the number of bits allocated by adding the number of bits allocated to the subchannel of which the cost function is the sum of the functions for the reduction of the maximum allowable allocated bits of the subchannel.

A fourth aspect of the present invention provides a binder including a plurality of lines, a plurality of subscriber side modems respectively connected to the plurality of lines, a plurality of base station side modems respectively connected to the plurality of lines, and each subchannel of the plurality of lines. And a spectrum manager to determine the number of allocated bits and power of the channel, wherein the spectrum manager determines the number of allocated bits of the subchannels of at least one of the lines using the collected channel information. Adding the number of allocated bits to the subchannel with the minimum cost function, which is the sum of the function for increasing or decreasing the power of the subchannel and the function of reducing the maximum allowed allocated bits of the subchannel of at least one of the remaining lines. It provides an MC DSL system for determining the number of bits allocated.

Hereinafter, a symbol synchronization apparatus according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings. However, embodiments of the present invention may be modified in various forms, and the scope of the present invention should not be construed as being limited by the embodiments described below. Embodiments of the present invention are provided to more fully describe the present invention to those skilled in the art.

2 is a diagram briefly showing an MC DSL system according to a first embodiment of the present invention.

Referring to FIG. 2, the MC DSL system includes a base station apparatus 100, a binder 200, and first to M subscriber side modems Modem_R1 to Modem_RM. The base station apparatus 100 includes a spectrum management unit 110 and first to M base station side modems Modem_C1 to Modem_CM, and the binder 200 is provided with the first to M lines L1 to LM.

The first base station-side modem Modem_C1 communicates with the first subscriber-side modem Modem_R1 through the first line L1. At this time, the communication is performed in a multi-carrier manner. In addition, during communication or during an initialization process, the first base station-side modem Modem_C1 and the first subscriber-side modem Modem_R1 measure various parameters required for spectrum management. In the same manner, the second base station-side modem Modem_C2 communicates with the second subscriber-side modem Modem_R2 through the second line L2, and the third base station-mode modem Mode_C3 connects the third line L3. Communicate with the third subscriber-side modem (Modem_R3).

In the drawing, P1 means the square of the magnitude of the transfer function of the signal transmitted from the first subscriber-side modem Modem_R1 to the first base station-side modem Mode_C1 through the first line L1. In the same manner, P2 means the square of the magnitude of the transfer function of the signal transmitted from the second subscriber-side modem Modem_R2 to the second base station-side modem Mode_C2 via the second line L2, and P3 is the third line. It means the square of the magnitude of the transfer function of the signal transmitted from the third subscriber-side modem (Modem_R3) to the third base station-side modem (Modem_C3) through (L3). P12 and P1M mean the effect of far end crosstalk (FEXT), P12 is crosstalk noise transmitted from the second subscriber-side modem (Modem_R2) to the first base station-side modem (Modem_C1) P1M means the square of the magnitude of the transfer function of crosstalk noise transferred from the Mth subscriber-side modem Modem_RM to the first base station-side modem Modem_C1.

The spectrum management unit 110 determines the number of bits allocated to the subchannels of each line and the power allocated to the subchannels of each line and transfers this information to each modem, or transmits a transmission power mask allocated to the subchannels of each line. It determines and delivers this information to each modem. In order to perform such a function, the spectrum management unit 110 first collects channel information from each modem. Thereafter, the spectrum manager 110 determines the number of bits and power allocated to the subchannels of each line by using the first method and / or the second method. Here, the first method is a method of calculating the cost function of each subchannel of a selected one of the lines, and selecting the subchannel having the smallest cost function to increase the number of allocated bits. In this case, the cost function is a function of the power to be added to increase the number of bits of the subchannel of the selected line and a function of the number of allocated bits reduced in the subchannel of the remaining line due to the addition of the power of the subchannel. It is calculated as the sum of. The second method is a method of calculating a cost function of each subchannel of a selected one of the lines and increasing the number of allocated bits by selecting a subchannel having the smallest cost function, as in the first method. The only difference is that the cost function is calculated as a function of the number of allocated bits that must be reduced in the subchannels of the remaining lines in order to increase the number of bits of the subchannels of the selected line. In this way, by reducing the number of bits allocated to the subchannels of the remaining lines, that is, by reducing the power allocated to the subchannels of the remaining lines, the reason for increasing the number of bits allocated to the subchannels of the selected line is due to the FEXT generated from the remaining lines. This is because the effect is reduced. That is, since the SNR of the selected line is increased because the FEXT by the remaining lines is reduced, the bit allocation of the selected line can be increased. In this way, after determining the number of bits and power allocated to the subchannels of each line, the spectrum management unit 110 transmits the related information to each modem. At this time, the spectrum management unit may transmit information on the determined number of bits and power to each modem. In this case, each modem performs communication by allocating the determined number of bits and power to each subchannel. In addition, the spectrum manager 110 may transmit the determined power, that is, the maximum power mask, to each modem without transmitting information about the determined number of bits and power to each modem. In this case, each modem is in the range of the maximum power mask. Communication is performed by allocating bits to each subchannel within the channel.

3 is a view for explaining the operation of the spectrum management unit of FIG.

Referring to FIG. 3, the power allocated to each subchannel at the time of transmission in the first subscriber-side modem Modem_R1 and the subchannel at the time of transmission in the second subscriber-side modem Modem_R2 are shown in FIG. The power to be expressed is represented. Methods for increasing the number of bits allocated to the second subchannel SC2 of the first subscriber-side modem Modem_R1 are represented in FIGS. 3B, 3C, and 3D. Among these methods, the method represented in FIG. 3B is a method commonly used in the art, and increases the number of bits allocated by increasing the transmission power of the second subchannel SC2 of the first subscriber-side modem Modem_R1. It is a way. 3 (c) illustrates a method of increasing the number of allocated bits of the first subscriber-side modem Modem_R1 by the second method. The transmission power of the second subchannel SC2 of the second subscriber-side modem Modem_R2 is increased. By decreasing, the number of bits allocated to the second subchannel SC2 of the first subscriber-side modem Modem_R1 is increased. FIG. 3D illustrates a method of increasing the number of bits allocated to the first subscriber-side modem Modem_R1 by the first method. The transmission power of the second subchannel SC2 of the first subscriber-side modem Modem_R1 is increased. It is expressed that the number of bits allowed for the second subchannel SC2 of the second subscriber-side modem Modem_R2 is reduced, that is, the transmission power.

4 is a diagram illustrating an example of a spectrum management method of the MC DSL system illustrated in FIG. 2.

2 and 4, the spectrum management method includes measuring channel information of lines included in a binder (S100), collecting measured channel information (S200), and using each collected channel information. Determining the number of allocated bits of each subchannel of (S300), and the step of assigning bits to perform communication (S400).

In step S100 of measuring channel information of the lines L1 to LM included in one binder, the base station-side modems Modem_C1 to Modem_CM or the subscriber-side modems Modem_R1 to Modem_RM measure information on each channel. Channel information of the upstream (upstream) transmitted from the terminal to the base station is measured by the base station-side modems (Modem_C1 to Modem_CM), and channel information of the downstream stream (downstream) transmitted from the base station to the terminal is the subscriber-side modems (Modem_R1 to Modem_RM) Measure at Channel information to be measured includes loop loss, FEXT, and background noise power of each line.

For upstream, the line attenuation of the mth line (Lm, m is an integer greater than or equal to 1 and less than or equal to M) is the power of the signal transmitted from the mth subscriber side modem (Modem_Rm) and the mth base station side modem (Modem_Cm) This can be obtained by measuring the power of the signal received by. FEXT from the nth line (Ln, n is an integer greater than or equal to 1 and less than or equal to M) to the mth line Lm is a subscriber side modem (Modem_R1 to Modem_R (n-1)) other than the nth subscriber side modem (Modem_Rn). , Modem_R (n + 1) to Modem_RM do not transmit a signal, and only the nth subscriber-side modem Modem_Rn transmits a predetermined signal, and the power of the signal transmitted by the nth subscriber-side modem Modem_Rn This can be obtained by measuring the power of the signal transmitted from the nth subscriber-side modem Modem_Rn to the mth base station-side modem Modem_Cm. The background noise of the m-th line Lm can be obtained by measuring the power of the received signal in the m-th base station-side modem Modem_Cm while all the subscriber-side modems Modem_R1 to Modem_Rm do not transmit a signal.

In the case of the downstream, the line attenuation of the mth line Lm can be obtained by measuring the power of the signal transmitted by the mth base station modem Modem_Cm and the power of the signal received by the mth subscriber modem Modem_Rm. . The FEXT from the nth line Ln to the mth line transmits a signal to the base station-side modems Modem_C1 to Modem_C (n-1) and Modem_C (n + 1) to Modem_CM other than the nth base station-side modem Modem_Cn. Otherwise, in the state where only the nth base station side modem Modem_Cn transmits a predetermined signal, the power of the signal transmitted from the nth base station side modem Modem_Cn and the mth subscriber side modem from the nth base station side modem Modem_Cn Can be obtained by measuring the power of the signal transmitted in (Modem_Rm). The background noise of the m-th line Lm can be obtained by measuring the power of the received signal in the m-th subscriber-mode modem Modem_Rm without all of the base station-side modems Modem_C1 to Modem_Cm transmitting a signal.

In the step of collecting the measured channel information (S200), the spectrum management unit 110 collects the channel information measured by the base station-side modem (Modem_C1 to Modem_CM) or subscriber-side modem (Modem_R1 to Modem_RM). Since the spectrum management unit 110 is located in the base station 100, the channel information measured by the base station-side modems Modem_C1 to Modem_CM is directly transmitted to the spectrum management unit 110, but the channel measured by the subscriber-side modems Modem_R1 to Modem_RM is measured. The information is transmitted to the spectrum management unit 110 via the base station side modems Modem_C1 to Modem_CM.

In step S300 of determining the number of allocated bits of each subchannel of each line by using the collected channel information, the number of allocated bits of each subchannel is sequentially determined from the first line L1 to the Mth line LM. do. That is, the number of allocated bits of each subchannel of the first line L1 is first determined (S310 (1), S320 (1), and S330 (1)), and then the allocation of each subchannel of the second line L2. The number of bits is determined (S310 (2), S320 (2), S330 (2)), and then each subchannel of the third to (M-1) th lines L3 to L (M-1) in the same manner. The number of allocated bits of is determined, and finally, the number of allocated bits of each subchannel of the M-th line LM is determined (S310 (M)). The order of the first to M lines L1 to LM may be determined in order of increasing average SNR. That is, the line having the lowest average SNR is used as the first line L1, the line having the lowest average SNR next to the first line is used as the second line L2, and the line having the highest average SNR is the Mth line LM. ) Can be placed. The average SNR can be found using signal power and noise power, the signal power can be found using measured line attenuation, and the noise power is measured crosstalk noise transfer function and background noise power. Can be obtained using When the number of allocated bits is preferentially determined from a line with a low average SNR, even a line with a low average SNR can obtain a certain level of transmission rate, that is, the number of allocated bits. However, a line with a low average SNR cannot achieve a sufficient transmission speed.

The first through (M-1) lines (L1 through L (M-1)) determine the number of allocated bits of each subchannel in the same manner, and the method determines the number of allocated bits of each subchannel by the first method. Step S310, determining whether the allocated total number of bits corresponds to the allowable total number of bits (S320), and determining the number of allocated bits of each subchannel by the second method (S320). The M-th line LM includes only the step S310 (M) of determining the number of allocated bits of each subchannel in the first method.

In the step S310 of determining the number of bits allocated to each subchannel by the first method, the first method refers to a method of increasing the number of bits allocated to each subchannel by increasing the power allocated to each subchannel. According to the first method, the number of allocated bits of each subchannel is determined by calculating a cost function as shown in Equation 1 and adding one bit to a subchannel having a minimum value of the cost function. Can be.

Cm (i) = 10 × log ₁₀ (ΔSm (i)) + F (−ΔBMAXn (i))

In Equation 1, Cm (i) denotes a cost function of the i-th subchannel of the m-th line Lm, and ΔSm (i) adds 1 bit to the i-th subchannel of the m-th line Lm. In order to mean additional power required. In addition, n means an integer of m + 1 to M, and -Δ BMAX n (i) is to be allocated to the i sub-channel of the n-th line to the maximum when one bit is added to the i sub-channel of the m-th line. The number of bits can be reduced, and BMAXn (i) can be calculated as in Equation 2, and F (-ΔBMAXn (i)) means an appropriate function for -ΔBMAXn (i). , An example thereof is as shown in Equation (3).

BMAXn (i) = log ₂ (1 + SNRMAXn (i) / Γ)

F (-ΔBMAXn (i)) = -ΔBMAX (m + 1) (i)-ΔBMAX (m + 2) (i)-...-ΔBMAXM (i)

In Equation 2, SNRMAXn (i) denotes an allowable maximum SNR of the i-th subchannel of the n-th line, and Γ means an SNR gap.

 In this way, the operation of calculating the cost function and adding one bit to the subchannel having the minimum value of the cost function is repeatedly performed within a range not exceeding the allowable total number of bits and the allowable maximum power. In other words, if the total number of bits, that is, the sum of the bits allocated to all subchannels belonging to the corresponding line Lm is equal to the allowable total number of bits, the operation of adding one bit to the subchannel as described above is stopped. . In addition, when one bit cannot be added to all subchannels of the corresponding line Lm without exceeding the allowable maximum power, the operation of adding one bit to the subchannel as described above is stopped.

In the step S320 of determining whether the allocated total number of bits corresponds to the allowable total number of bits, if the total number of allocated bits of the line Lm is equal to the total number of bits allowed on the line, then the next line L (m If the total number of bits allocated to the corresponding line Lm is smaller than the total number of bits allowed for the corresponding line, the number of bits allocated to each subchannel in the second method is reached. Proceed to step S320 to determine.

In the step S320 of determining the number of bits allocated to each subchannel by the second method, the second method is to reduce the maximum allowable number of allocated bits of the line following the line, thereby reducing the number of bits allocated to each subchannel of the line. Means how to increase. If the line is assumed to be the mth line Lm, if the maximum allowable number of allocated bits of the lines following the line, i.e., the (m + 1) to the M lines (L (m + 1) to LM) are reduced, Since the FEXT from m + 1) to M tracks L (m + 1) to LM decreases to the mth track Lm, the number of bits that can be allocated to the mth track increases. According to the second method, for example, the number of bits to be allocated to each subchannel is determined by calculating a cost function as shown in Equation 4 and adding 1 bit to the subchannel having the minimum value of the cost function. Can be.

Cm (i) = F (-ΔBMAXn (i))

In the above equation, -ΔBMAXn (i) means a reduction in the maximum number of bits that can be allocated to the i th subchannel of the nth line to add 1 bit to the i th subchannel of the nth line. , F (−ΔBMAXn (i)) means an appropriate function for −ΔBMAXn (i).

As described above, the operation of calculating the cost function and adding one bit to the subchannel having the minimum value of the cost function is repeatedly performed within the range satisfying Equation 5 for all the subchannels without exceeding the allowable total number of bits. Is performed.

Pm (i) / Nm (i) ≤ Pn (i) / Nn (i)

SNRMAXn (i)-SNRm (i) ≥ T

In Equation 5, Pm (i) denotes the square of the transfer function of the i-th subchannel of the m-th line Lm, and Nm (i) denotes the noise power of the i-th subchannel of the m-th line Lm. Pn (i) means the square of the transfer function of the i th subchannel of the nth line Ln, and Nn (i) means the noise power of the i th subchannel of the nth line Ln. , SNRMAXn (i) means the allowable maximum SNR of the i-th subchannel of the n-th line (Ln), SNRm (i) means the average SNR of the i-th subchannel of the m-th line (Lm), T is It means a predetermined constant.

In operation S400, the spectrum management unit 110 transmits the determined number of allocated bits and power to the base station-side modems Modem_C1 to Modem_CM and the subscriber-side modems Modem_R1 to Modem_RM. The modems Modem_C1 to Modem_CM and the subscriber-side modems Modem_R1 to Modem_RM allocate bits and power to each subchannel to perform communication. If the channel information measured in step S100 of measuring the channel information of the lines included in the binder is upstream information, the transmitter (not shown) of the subscriber-side modems Modem_R1 to Modem_RM and the base station-side modems Modem_C1 to Modem_CM Receiver (not shown) performs communication according to the determined number of allocated bits, and when the measured channel information is downstream information, the transmitter (not shown) and the subscriber-side modem (Modem_R1) of the base station modems Modem_C1 to Modem_CM. The communication unit performs communication according to the determined number of allocated bits.

Further, in the step of performing communication by allocating bits (S400), the spectrum manager 110 may transmit only the determined allocated power, that is, the maximum power mask, to the base station side modems Modem_C1 to Modem_CM and the subscriber side modems Modem_R1 to Modem_RM. have. In this case, the base station-side modem or the subscriber-side modem receiving the maximum power mask allocates bits to each subchannel within the range of the maximum power mask to perform communication.

FIG. 5 is a graph illustrating a speed range of an MC DSL system based on OSB technology having the highest performance among the aforementioned prior arts and an MC DSL system according to an embodiment of the present invention.

Referring to FIG. 5, it can be seen that there is no significant difference in the performance of the MC DSL system by the OSB technology and the MC DSL system by the embodiment of the present invention. On the contrary, in the time required to calculate the number of bits allocated to the lines included in the binder, it was confirmed that the MC DSL system based on the OSB technology takes several times more than the MC DSL system according to the embodiment of the present invention.

Various changes may be made in the present invention without departing from the spirit or scope of the invention. Accordingly, the foregoing description of the embodiments according to the present invention will be provided for purposes of illustration only, and not for the purpose of limiting the invention as defined by the appended claims and their equivalents.

The spectrum management method of the multi-carrier digital subscriber line system and the base station apparatus used in the present invention have a high performance while having a small amount of calculation.

1 is a graph illustrating the rate region of dynamic spectrum management techniques.

2 is a diagram briefly showing an MC DSL system according to a first embodiment of the present invention.

3 is a view for explaining the operation of the spectrum management unit of FIG.

4 is a diagram illustrating an example of a spectrum management method of the MC DSL system illustrated in FIG. 2.

FIG. 5 is a graph illustrating a speed range of an MC DSL system based on OSB technology having the highest performance among the aforementioned prior arts and an MC DSL system according to an embodiment of the present invention.

Claims (16)

(a) measuring channel information of the lines included in the binder; (b) collecting the measured channel information; (c) determining the number of allocated bits of the subchannels of at least one of the lines using the collected channel information, wherein at least one of a function of power increase and decrease of the subchannels of the one line and the remaining lines Determining the number of allocation bits in such a manner as to add the number of allocation bits to the subchannel having the minimum cost function, which is the sum of the functions for decreasing the maximum allowable allocation bits of the subchannel of the line; And (d) allocating bits to each subchannel of the lines according to the determined number of allocated bits and power to perform communication. (a) measuring channel information of the lines included in the binder; (b) collecting the measured channel information; (c) determining the number of allocated bits of the subchannels of at least one of the lines using the collected channel information, wherein at least one of a function of power increase and decrease of the subchannels of the one line and the remaining lines Determining the number of allocation bits in such a manner as to add the number of allocation bits to the subchannel having the minimum cost function, which is the sum of the functions for decreasing the maximum allowable allocation bits of the subchannel of the line; And (d) delivering the determined allocated power to modems connected to the lines as a maximum power mask, the modems assigning bits to each subchannel within the range of the maximum power mask to perform communication; Spectrum management method of MC DSL system. The method of claim 1 or 2, The measured channel information includes line attenuation, FEXT, and background noise power. The method of claim 1 or 2, Step (c) includes determining the number of allocated bits of the first line to be sequentially performed, and determining the number of allocated bits of the M-th line (M denotes the number of lines included in the binder). Determining the number of allocated bits of the m-th line (meaning an integer of 1 or more and less than (M-1)) of these steps (e) increasing the number of bits allocated to each subchannel by increasing the power allocated to each subchannel of the m-th line; (f) if the total number of allocated bits corresponds to the allowable total number of bits, go to determining the number of allocated bits of the (m + 1) line; otherwise, go to step (g); (g) increasing the number of allocated bits of the subchannels of the m line by reducing the maximum allowed allocation bits of the subchannels of the n line (n means an integer greater than or equal to m + 1 and less than or equal to M), Determining the number of bits allocated to the M-th line (h) increasing the number of bits allocated to each subchannel by increasing the power allocated to each subchannel of the Mth line. The method of claim 4, wherein And the first to M lines are arranged in order of increasing average SNR. The method of claim 4, wherein Step (e) is a function of the power to be added in order to increase the number of bits allocated to the subchannels of the m line and the maximum allowance to be reduced in the subchannels of the n line due to the addition of the power of the subchannel A method of spectrum management in an MC DSL system that determines the number of allocated bits by adding an allocated number of bits to a subchannel having a minimum cost function that is a sum of a function of allocated number of bits. The method of claim 4, wherein The step (e) iteratively repeats the step of increasing the power by adding one bit to the subchannel having the minimum value of the cost function by calculating a cost function for each subchannel of the m-th line as follows. By doing, Cm (i) = 10 × log ₁₀ (ΔSm (i)) + F (−ΔBMAXn (i)) In the above equation, Cm (i) denotes a cost function of the i-th subchannel of the m-th line, and ΔSm (i) denotes additional power required to add 1 bit to the i-th subchannel of the mth line. ΔBMAXn (i) is a reduction of the maximum number of bits that can be allocated to the i th subchannel of the nth line to the maximum when 1 bit is added to the i th subchannel of the nth line, and F ( ΔBMAXn (i)) means a predetermined function for ΔBMAXn (i). The method of claim 7, wherein In step (e), adding the 1 bit and increasing the allocated power may not add the 1 bit without the total number of allocated bits being equal to the allowed total number of bits or exceeding the maximum allowable power for all subchannels. Spectrum management method of the MC DSL system repeatedly performed until. The method of claim 4, wherein In step (g), a cost function is calculated for each subchannel of the mth line by adding a bit to a subchannel having a minimum value of the cost function of the mth line, and adding the 1st bit to the nth line. By repeatedly performing steps to reduce the allocated power of the line, Cm (i) = F (-ΔBMAXn (i)) In the above equation, Cm (i) denotes a cost function of the i subchannel of the mth line, and -ΔBMAXn (i) denotes the first subchannel of the nth line to add 1 bit to the i subchannel of the nth line. In the MC DSL system, the number of bits that can be allocated to the i subchannel of the n-line can be allocated to the maximum, and F (-ΔBMAXn (i)) means a predetermined function of -ΔBMAXn (i). Spectrum Management Method. The method of claim 9, The step (g) adds the 1 bit and decreases the allocated power to all subchannels of the m-th line within a range in which the total number of allocated bits is equal to the allowed total number of bits or satisfies the following equations. Repeat until 1 bit cannot be added to Pm (i) / Nm (i) ≤ Pn (i) / Nn (i) SNRMAXn (i)-SNRm (i) ≥ T In the above equation, Pm (i) means the square of the transfer function of the i-th subchannel of the m-th line, Nm (i) means the noise power of the i-th subchannel of the m-th line, and Pn (i Is the square of the transfer function of the i-th subchannel of the nth line, Nn (i) is the noise power of the i-th subchannel of the nth line, and SNRMAXn (i) is the nth line The mean maximum SNR of the i-th sub-channel of the, SNRm (i) means the average SNR of the i-th sub-channel of the m-th line, T is a predetermined constant management method of the MC DSL system. A plurality of base station side modems each connected to a plurality of lines located in one binder; And A spectrum manager configured to determine the number of bits and power allocated to each subchannel of the plurality of lines; The spectrum manager determines the number of allocated bits of the subchannels of at least one of the lines using the collected channel information, wherein at least one of a function of power increase and decrease of the subchannels of the one line and the remaining lines MC DSL base station apparatus for determining the number of allocation bits by adding the number of allocation bits to the subchannel with the minimum cost function, which is the sum of the functions for the reduction of the maximum allowable allocation bits of the subchannel of one line. A binder including a plurality of lines; A plurality of subscriber side modems respectively connected to the plurality of lines; A plurality of base station side modems respectively connected to the plurality of lines; And A spectrum manager configured to determine the number of bits and power allocated to each subchannel of the plurality of lines; The spectrum manager determines the number of allocated bits of the subchannels of at least one of the lines using the collected channel information, wherein at least one of a function of power increase and decrease of the subchannels of the one line and the remaining lines MC DSL system for determining the number of bits allocated by adding the number of bits allocated to the sub-channel with the minimum cost function, which is the sum of the functions for the reduction of the maximum allowable allocated bits of the sub-channel of one line. The method of claim 12, The spectrum management unit delivers the determined number of allocated bits and power to the plurality of base station-side modems and the plurality of subscriber-side modems. The method of claim 13, The plurality of base station-side modems and the plurality of subscriber-side modems receiving the allocated number of bits and power may perform communication by allocating the number of bits and power to each subchannel according to the number of allocated bits and power. The method of claim 12, And the spectrum management unit delivers a maximum power mask to the plurality of base station side modems or the plurality of subscriber side modems. The method of claim 15, The plurality of base station-side modems or the plurality of subscriber-side modems to which the allocated number of bits and the power are transmitted are allotted the number of bits of each subchannel within the range of the maximum power mask to perform communication.