CN101741426A - Method, device and system for enhancing stability of DSL circuit - Google Patents

Abstract

The invention provides a method, a device and a system for enhancing stability of DSL circuit. The method comprises the following steps: obtaining actual noise of a receiver end on the DSL subcarrier; performing statistical analysis to the actual noise of the receiver; determining reference virtual noise according to the statistical analysis of the obtained actual noise of the receiver on the subcarrier and relevant parameters of SOS mechanism for urgent speed reduction and configuring a user template according to the related parameters of SOS and the determined reference virtual noise. The scheme of the invention needs not to set the virtual noise at the maximum, when the actual noise is lower than the virtual noise, the speed of the user can be avoided from losing too much, and when the condition for starting urgent speed reduction mechanism SOS is satisfied, the urgent speed reduction mechanism SOS can be started to ensure the stability of user service.

Description

A kind of method, Apparatus and system that improves the DSL track stability

Technical field

The present invention relates to the communications field, relate in particular to a kind of method, Apparatus and system of the DSL of raising track stability.

Background technology

The DSL technology is a kind of twisted pair telephone that passes through, it is the high speed transmission technology that unshielded twisted pair is carried out transfer of data, comprise ADSL (Asymmetric Digital Subscriber Line) (Asymmetrical Digital Subscriber Line, ADSL), Very-high-speed Digital Subscriber Line (Very-high-bit-rate Digital Subscriber Line, VDSL), based on integrated services digital network (Integrated Services Digital Network, ISDN) number of users word line (ISDN Digital Subscriber Line, IDSL), single-line high speed digital subscriber line (Single-pair High-bit-rate Digital Subscriber Line, SHDSL), second generation ADSL (Asymmetric Digital Subscriber Line) (Asymmetrical Digital Subscriber Line 2, ADSL2), the second generation ADSL (Asymmetric Digital Subscriber Line) of extended frequency band (Asymmetrical Digital Subscriber Line2plus, ADSL2plus), second generation Very-high-speed Digital Subscriber Line (Very-high-bit-rate DigitalSubscriber Line 2, VDSL2) etc.

In various digital user line technologies (xDSL), except the DSL of baseband transmission such as IDSL and SHDSL, adopt the DSL of passband transmission to utilize frequency multiplexing technique to make DSL and Plain Old Telephone Service (Plain Old Telephone Service, POTS) coexist as with on a pair of twisted-pair feeder, wherein DSL occupies high band, POTS takies the following baseband portion of 4KHz, POTS signal and DSL signal by separate/integrator (Splitter) separates or merges.

Since each line of the employed twisted-pair feeder of DSL between be non-shielding, line to electromagnetic interference can cause the signal on a pair of twisted-pair feeder signal on the other a pair of twisted-pair feeder is exerted an influence, promptly crosstalk.Along with the development of DSL technology, speed is more and more higher, and spectral range is more and more wideer.In the DSL of a new generation technology VDSL2, the maximum two-way 200Mbps of line speed, spectral range can reach 30MHz.So wide spectral range causes VDSL2 very responsive to the noise of crosstalking between cable, radio frequency interference couplings such as (RFI) is come, and can occur error rate height in actual applications, situations such as drop rate height.

Virtual noise (Virtual Noise) scheme is wherein a kind of method that improves track stability.In the pre-configured transmitting terminal reference virtual of the transmitting terminal of DSL, reference virtual will pass to receiving terminal in the process of DSL training, receiving terminal can obtain the attenuation characteristic Hlog (f) of each subcarrier in training process, and calculates the reference virtual at receiving terminal.Receiving terminal is got wherein maximum with the receiving terminal actual noise and the receiving terminal reference virtual that obtain in the training process, determine the bit and the gain of the distribution on each subcarrier again, thereby guarantee behind the DSL line activation, have on each subcarrier than higher noise margin, can resist contingent noise jamming, improve the stability of circuit.

The inventor finds, though use above-mentioned virtual noise technology can improve the stability of circuit to a certain extent, also sacrificed the line speed of user's focus attentions equally on when guaranteeing circuit stable to greatest extent.

Summary of the invention

The object of the present invention is to provide a kind of method, Apparatus and system of the DSL of raising track stability, when can avoid improving track stability in the prior art, sacrifice the transmission rate of subscriber's line.

Technical scheme of the present invention:

A kind of method that improves the DSL track stability, the method comprising the steps of:

Obtain the actual noise of the receiving terminal on the DSL subcarrier;

Described receiving terminal actual noise is carried out statistical analysis;

According to the statistical analysis of the receiving terminal actual noise of the receiving terminal actual noise of the described subcarrier that obtains and the described subcarrier that obtains and the relevant parameter that urgent speed reduces machine-processed SOS, determine reference virtual;

According to the relevant parameter of SOS and the reference virtual configure user template of determining.

A kind of in DSL the method for configure user template, the method comprising the steps of:

A, the relevant parameter that reduces machine-processed SOS according to urgent speed are determined reference virtual;

B, according to the relevant parameter of described SOS and definite reference virtual configure user template.

A kind of Digital Subscriber Line Access Multiplexer comprises housing, transmitting element and receiving element, and described transmitting element and receiving element are arranged in the housing, is used for the transmission and the reception of data, it is characterized in that this Digital Subscriber Line Access Multiplexer comprises:

The noise acquiring unit is used to obtain the receiving terminal actual noise on the DSL subcarrier;

Statistical analysis unit is carried out statistical analysis to described receiving terminal actual noise;

Computing unit is used for determining reference virtual according to the statistical analysis of the receiving terminal actual noise of the receiving terminal actual noise of the described subcarrier that obtains and the described subcarrier that obtains and the relevant parameter that urgent speed reduces machine-processed SOS.

A kind of broadband network system comprises:

Local side apparatus;

Ustomer premises access equipment, and;

The reference virtual determination module is arranged in local side apparatus or the network management system, and this reference virtual determination module has: the noise acquiring unit is used to obtain the receiving terminal actual noise on the DSL subcarrier; Statistical analysis unit is carried out statistical analysis to described receiving terminal actual noise; And computing unit, be used for determining reference virtual according to the statistical analysis of the receiving terminal actual noise of the receiving terminal actual noise of the described subcarrier that obtains and the described subcarrier that obtains and the relevant parameter that urgent speed reduces machine-processed SOS.

Beneficial effect of the present invention: embodiments of the invention are provided with virtual noise in conjunction with the characteristic of SOS; when using virtual noise; cooperate SOS; with regard to unnecessary virtual noise be provided with very big; under the situation of noise less than virtual noise; the too much unnecessary loss of user rate can be avoided, under the situation of noise, the stability that SOS protects customer service can be started greater than virtual noise.Simultaneously, because the setting of virtual noise is arranged, the startup of SOS can be so not frequent yet, and the number of times that speed reduces has obtained effective control.Can give full play to the strong point of virtual noise technology and SOS technology like this, avoid defective separately, can guarantee that track stability does not lose the purpose of too much transmission rate again thereby reach.

Description of drawings

Fig. 1 is the system architecture schematic diagram of the embodiment of the invention;

Fig. 2 is the method flow diagram of the embodiment of the invention.

Embodiment

As shown in Figure 1, the broadband network system of the embodiment of the invention, comprise: ustomer premises access equipment 12 and local side apparatus 16, ustomer premises access equipment 12 is generally digital subscriber link modem, it links with local side apparatus 16, ustomer premises access equipment 12 can send message to local side apparatus 16, also can receive and handle the message that local side apparatus 16 sends simultaneously.

Local side apparatus 16 is specially Digital Subscriber Line Access Multiplexer (DSLAM, Digital SubscriberLine Access Multiplexer), Digital Subscriber Line Access Multiplexer comprises housing, transmitting element and receiving element, described transmitting element and receiving element are arranged in the housing, are used for the transmission and the reception of data.

The reference virtual determination module of the embodiment of the invention can be arranged in the local side apparatus 16 or in the network management system according to actual needs, also can be independent of miscellaneous equipment and be provided with separately.The reference virtual determination module specifically comprises: the noise acquiring unit is used to obtain the receiving terminal actual noise on the DSL subcarrier; Statistical analysis unit is carried out statistical analysis to described receiving terminal actual noise; And computing unit, be used for receiving terminal actual noise and the statistical analysis of the receiving terminal actual noise of the subcarrier that obtains and the relevant parameter that urgent speed reduces machine-processed SOS according to the subcarrier that obtains, determine reference virtual.

As shown in Figure 2, the method for the embodiment of the invention may further comprise the steps:

S201, noise acquiring unit obtain the actual noise of the receiving terminal on the DSL subcarrier, and be as shown in table 1 below:

Table 1

Wherein K represents the number of tone, and T represents the number of times of collection parameter.

In this step, the method of obtaining the receiving terminal actual noise of DSL has multiple, the noise acquiring unit can wherein can have following three kinds of methods by indirect calculation at least by direct measurement or by indirect calculation or read the actual noise that data with existing obtains the receiving terminal on the DSL subcarrier:

Method one: enable online reconfiguration (On-Line Reconfiguration, OLR) characteristic, and monitoring period is set in advance; In monitoring period, collect the parameter of adjusted each subcarrier of online reconfiguration, the calculation of parameter of each subcarrier that obtains in parameter of reshuffling adjusted each subcarrier that utilization is collected and the training process is by calculating the receiving terminal actual noise on each subcarrier of DSL.

Defined the online reconfiguration characteristic in the DSL standard, in line condition or the slow variation of external noise environment generation, allow DSL under the prerequisite that does not go offline, automatically adjust current configuration parameter, to guarantee that DSL still can keep preferable performance and stability.The online reconfiguration characteristic mainly comprises: and bit exchange (Bit Swapping, BS); The dynamic rate correction (Dynamic RateRepartition, DRR); The seamless rate adjustment (Seamless Rate Adaptation, SRA) etc.

Wherein, bit exchange refers to according to the signal to noise ratio on current each subcarrier, redistribute the bit (Bi on each subcarrier, 0＜i≤subcarrier number) and the gain (Gi, 0＜i≤subcarrier number), promptly adjust Bi and Gi, but total speed (∑ Lp) remains unchanged, wherein Lp is each physical medium relevant (sublayer) (Physical Media Dependent (sublayer), PMD) bit number of p time-delay passage carrying in the symbol; DRR refers to according to the signal to noise ratio on current each subcarrier, redistributes the bit of each time delay passage, promptly adjusts Lp, but total speed (∑ Lp) remains unchanged; SRA refers to according to the signal to noise ratio on current each subcarrier, redistributes the bit of each time delay passage, promptly adjusts Lp, adjusts the bit and the gain of each subcarrier simultaneously, in other words, adjusts Bi and Gi, and this moment, total speed (∑ Lp) can change.

The online reconfiguration characteristic allows DSL in the process that activates, variation and predefined target noise margin according to the line conditions generation, adjust bit carrying number and transmitted power on each subcarrier within the specific limits, adapt to the circuit noise variation thereby reach, keep the purpose of track stability.Conversely, the noise situation of change on the circuit has also been reacted in the adjustment of online reconfiguration.Therefore, by adjusted each parameter of collection online reconfiguration, and the parameter of each subcarrier that obtains in the training process, can calculate the size of circuit noise, i.e. the receiving terminal actual noise of each subcarrier at this moment.By the statistics of a period of time (i.e. Yu She monitoring period), can draw the maximum noise value of the receiving terminal actual noise of each subcarrier on the circuit.Can determine reference virtual according to this maximum noise value, utilize the reference virtual of determining that DSL reference virtual parameter is configured, thereby the DSL circuit noise tolerance limit after having guaranteed to activate can be resisted contingent noise jamming.

Wherein, the parameter of each collected subcarrier comprises: the bit of the power spectral density of each subcarrier, signal to noise ratio surplus and distribution; The parameter of each subcarrier that obtains in the training process comprises: the attenuation characteristic of each subcarrier.Perhaps, the parameter of each collected subcarrier comprises: the signal to noise ratio surplus of each subcarrier, the bit and the gain of distribution; The parameter of each subcarrier that obtains in the training process comprises: the attenuation characteristic of each subcarrier and reference power spectrum density.

Method two: set in advance the retraining monitoring period, or the retraining number of times; In the retraining monitoring period, or in the retraining number of times, collect the parameter of each subcarrier after training; The calculation of parameter of each subcarrier that utilization is collected is by calculating the receiving terminal actual noise on each subcarrier of DSL.

Because in the training process of DSL, receiving terminal can be measured the characteristic of channel, obtain the attenuation characteristic Hlog (i) and the receiving terminal actual noise Actual_Received_Noise (i) of each subcarrier on the channel, thereby calculate the signal to noise ratio snr (i) of each subcarrier, and calculate the bit (Bi of the distribution of each subcarrier, 0＜i≤subcarrier number) and the gain (Gi, 0＜i≤subcarrier number).Conversely, transmitting terminal and receiving terminal be by the modulation system and the agreement of standard code, and exchange parameter mutually obtains the Bi of receiving terminal, Gi, and Hlog (i) etc. can calculate receiving terminal actual noise Actual_Received_Noise (i).Through " repeatedly retraining ", can draw the maximum noise value of the receiving terminal actual noise of each subcarrier on the circuit.

Wherein, the parameter of each subcarrier after the collected training can comprise: the bit and the attenuation characteristic of the power spectral density of each subcarrier, signal to noise ratio surplus, distribution; The parameter of each subcarrier after the collected training also can comprise: the signal to noise ratio surplus of each subcarrier, the bit of distribution, gain, attenuation characteristic and reference power spectrum density.

Method three: set in advance DELT number of Dual-Ended Loop Test; In the Dual-Ended Loop Test number of times, from the test result of Dual-Ended Loop Test, obtain the receiving terminal actual noise on each subcarrier of DSL.

Because in DSL, defined the Dual-Ended Loop Test characteristic, the Dual-Ended Loop Test characteristic is in the DSL training process, entry-line diagnostic mode (Loop Diagnostic mode) carries out, and comprise the static noise QLN parameters such as (i) on the circuit among the output result of Dual-Ended Loop Test, this static noise is the receiving terminal actual noise on the DSL respective sub.Through carrying out repeatedly Dual-Ended Loop Test, can draw the maximum noise value of the receiving terminal actual noise of each subcarrier on the circuit.Can determine reference virtual according to this maximum noise value, utilize definite reference virtual that the reference virtual parameter of DSL is configured, thereby the DSL circuit noise tolerance limit after having guaranteed to activate can be resisted contingent noise jamming.

Therefore, carry out the single or multiple Dual-Ended Loop Test in this method, and from test result, obtain the receiving terminal actual noise on each subcarrier of DSL.

In the practical application, above-mentioned three kinds of methods can also be used in combination, and for example, make up wherein any two kinds, or use above-mentioned three kinds simultaneously.Receiving terminal actual noise on the collected DSL subcarrier some are better often.

S202, statistical analysis unit are carried out statistical analysis according to the receiving terminal actual noise on the collected DSL subcarrier to actual noise.

Can carry out statistical analysis according to the noise of each subcarrier, also can merge several subcarriers in groups, group is carried out statistical analysis.In this step, with all the receiving terminal actual noise orderings on each subcarrier or in each group, statistical computation parameter then: p _i ^k

Suppose that virtual noise is Noise (i), p _i ^kBe illustrated on k the subcarrier or k group in the probability of Noise＞VN+Margin (dB), as shown in table 2 below:

Table 2

??Index??i	??1	??2	??3	??4	??5	??6	??7	??8	??9	??10	...	?T
													??Noise k	??-61	??-65	??-68	??-71	??-72	??-75	??-77	??-89	??-83	??-88	...	?-86
??Number	??Num1	??Num2	??Num3	??Num4	??Num5	??Num6	??Num7	??Num8	??Num9	??Num10	...	?NumT
													??p i k	??p 1 k	??p 2 k	??p 3 k	??p 4 k	??p 5 k	??p 6 k	??p 7 k	??p 8 k	??p 9 k	??p 10 k	...	?p T k

Because the stability of noise allowance (Margin) with protection circuit is arranged when line activation; so when the situation of Noise＞VN+Margin (dB) occurring among certain the subcarrier k on the circuit or certain the group k; cyclic redundancy check (CRC) among subcarrier k or the group k increases, and threatens the stability of circuit.

S203, computing unit determine reference virtual according to the statistical analysis of the receiving terminal actual noise of the receiving terminal actual noise of the described subcarrier that obtains and the described subcarrier that obtains and the relevant parameter that urgent speed reduces machine-processed SOS.The parameter that SOS is relevant comprises one of startup probability of SOS subcarrier number SOS_NTONES or SOS cyclic redundancy check (CRC) SOS_CRC or SOS at least.In the present embodiment, the parameter that SOS is relevant is the target start probability of SOS_NTONES and SOS.

SOS is the another kind of method that improves track stability, after activating (showtime), certain period is interior because interference of noise, surpass maximum constraints and the cyclic redundancy check (CRC) (CRC that sets in advance when the number of these subcarriers, cyclic redundancy check) surpasses the maximum that sets in advance, to start SOS, and reduce the error rate and exceed the bit that is loaded on these subcarriers of normal level, and make these subcarriers have the more noise capacity.

Because urgent speed reduces the retraining that can avoid the DSL circuit to cause owing to noise effect after mechanism (SOS) starts, but can reduce the speed of DSL circuit, so, in conjunction with SOS a virtual noise is set and can maximizes the speed that the user can reach.

According to the statistics of step S202 to actual noise, when

The probability that k subcarrier may cause SOS is p _i ^kSo, the startup probability of SOS and SOS-NTONES and p _i ^kRelevant and obedience item distributes, and can represent with following expression so start the probability of SOS:

${\mathrm{Psos}}_i^k=\underset{t=N:K}{\mathrm{\Σ}}{C}_k^t\·{\left(p_i^k\right)}^t\·{(1-p_i^k)}^{K-t}$

If on k subcarrier different Noise _i ^kAs VN, can obtain different p _i ^k, obtain different Psos then _i ^k

Travel through all Noise _i ^k, make different Noise respectively _i ^kBe VN, calculate a Psos at each VN _i ^k, more all VN are calculated Psos _i ^kCompare with user's SOS target start probability, find out and the most approaching Psos of SOS target start probability _i ^k, this Psos then _i ^kFixed VN be the reference virtual of asking.

Specifically can carry out according to the following steps:

Get i=1, then $p_i^k=p_1^k,$ ${\mathrm{VN}}^k={\mathrm{Noise}}_1^k,$ k∈K

1, calculates ${\mathrm{Psos}}_i^k=\underset{t=N:K}{\mathrm{\Σ}}{C}_K^t\·{\left(p_i^k\right)}^t\·{(1-p_i^k)}^{K-t}$

2, compare Psos _i ^kTarget start probability with SOS:

If 3

The target start probability, i=i+1 then, repeating step 1～3;

If

The target start probability, Noise then _i ^kThe virtual noise of being asked exactly;

If The target start probability, Noise then _I-1 ^kThe virtual noise of being asked exactly.

The size of virtual noise can be adjusted according to user's requirement: if the user is not very high to the requirement of transmission rate, also do not wish frequent starting SOS, then can suitably strengthen virtual noise; If the user has relatively high expectations to transmission rate, and can tolerate the frequent starting of SOS, then can suitably reduce virtual noise, so that under the less situation of actual noise, have higher message transmission rate.

It is more accurate that those of ordinary skill in the art should be known in by above-mentioned steps S201, S202 and the resulting reference virtual of S203, but the flow process relative complex some.The technical staff determines roughly rule of thumb that directly the empirical value of a reference virtual also is fine under the situation of considering SOS.

S204: according to reference virtual and the SOS relevant parameter configure user template determined.

Because determining virtual noise in the step S204 of present embodiment is the startup probability according to parameter S OS_NTONES and SOS.So when the configure user template, come the configure user template according to the startup probability of SOS_NTONES that is obtained and SOS and the reference virtual that calculates.

And the configuration of the SOS_CRC parameter in template is as far as possible little, could make SOS_NTONES become the major parameter whether control starts SOS like this.

Certainly, if start SOS, after the speed of reduction DSL circuit, when the error rate on the subcarrier still exceeded normal level, then transmitting terminal and receiving terminal can restart to activate, and further increased the virtual noise that is sent.

Embodiments of the invention are provided with virtual noise in conjunction with the characteristic of SOS, when using virtual noise, cooperate SOS, with regard to unnecessary virtual noise be provided with very big, under the situation of noise less than virtual noise, the too much unnecessary loss of user rate can be avoided, under the situation of noise, the stability that SOS ensures customer service can be started greater than virtual noise.Simultaneously, because the setting of virtual noise is arranged, the startup of SOS can be so not frequent yet, and the number of times that speed reduces has obtained effective control.Can give full play to the strong point of virtual noise technology and SOS technology like this, avoid defective separately, can guarantee that track stability does not lose the purpose of too much transmission rate again thereby reach.

More than be explanation, in concrete implementation process, can carry out suitable improvement, to adapt to the needs of concrete condition the solution of the present invention to the specific embodiment of the invention.Therefore, the specific embodiment of the present invention just plays an exemplary role, not in order to restriction protection scope of the present invention.

Claims (11)

1. method that improves the DSL track stability, the method comprising the steps of:

Obtain the actual noise of the receiving terminal on the DSL subcarrier;

Described receiving terminal actual noise is carried out statistical analysis;

According to the statistical analysis of the receiving terminal actual noise of the receiving terminal actual noise of the described subcarrier that obtains and the described subcarrier that obtains and the relevant parameter that urgent speed reduces machine-processed SOS, determine reference virtual;

According to the relevant parameter of SOS and the reference virtual configure user template of determining.

2. method according to claim 1, it is characterized in that, receiving terminal actual noise on the described DSL of the obtaining subcarrier is specially: enable the online reconfiguration characteristic in advance, and monitoring period is set, in monitoring period, collect the parameter of adjusted each subcarrier of online reconfiguration, the calculation of parameter of each subcarrier that obtains in parameter of reshuffling adjusted each subcarrier that utilization is collected and the training process is by calculating the receiving terminal actual noise on each subcarrier of DSL; Or

Set in advance the Dual-Ended Loop Test number of times, in the Dual-Ended Loop Test number of times, from the Dual-Ended Loop Test result, obtain the receiving terminal actual noise on each subcarrier of DSL.

3. method according to claim 1, it is characterized in that, receiving terminal actual noise on the described DSL of the obtaining subcarrier is specially: set in advance retraining monitoring period or retraining number of times, collect the parameter of each subcarrier after training in the retraining monitoring period or in the retraining number of times, the calculation of parameter of each subcarrier that utilization is collected is by calculating the receiving terminal actual noise on each subcarrier of DSL.

4. method according to claim 3 is characterized in that, the parameter of each subcarrier after the training of described collection comprises: the bit and the attenuation characteristic of the power spectral density of each subcarrier, signal to noise ratio surplus, distribution; The parameter of each subcarrier after the collected training comprises: the signal to noise ratio surplus of each subcarrier, the bit of distribution, gain, attenuation characteristic and reference power spectrum density.

5. the method for a configure user template in DSL, the method comprising the steps of:

A, the relevant parameter that reduces machine-processed SOS according to urgent speed are determined reference virtual;

B, according to the relevant parameter of described SOS and definite reference virtual configure user template.

6. method according to claim 5 is characterized in that, the relevant parameter of described SOS comprises one of startup probability of SOS subcarrier number SOS_NTONES or cyclic redundancy check (CRC) SOS_CRC or SOS at least.

7. method according to claim 5 is characterized in that, described steps A is specially: the relevant parameter and the receiving terminal actual noise that reduce machine-processed SOS according to urgent speed are determined reference virtual.

8. a Digital Subscriber Line Access Multiplexer comprises housing, transmitting element and receiving element, and described transmitting element and receiving element are arranged in the housing, is used for the transmission and the reception of data, it is characterized in that this Digital Subscriber Line Access Multiplexer comprises:

The noise acquiring unit is used to obtain the receiving terminal actual noise on the DSL subcarrier;

Statistical analysis unit is carried out statistical analysis to described receiving terminal actual noise;

Computing unit is used for determining reference virtual according to the statistical analysis of the receiving terminal actual noise of the receiving terminal actual noise of the described subcarrier that obtains and the described subcarrier that obtains and the relevant parameter that urgent speed reduces machine-processed SOS.

9. Digital Subscriber Line Access Multiplexer according to claim 8 is characterized in that, the receiving terminal actual noise on the described DSL of the obtaining subcarrier is specially: directly measurement is obtained or is obtained or read data with existing by indirect calculation and obtains.

10. broadband network system comprises:

Local side apparatus;

Ustomer premises access equipment, and;

The reference virtual determination module is arranged in local side apparatus or the network management system, and this reference virtual determination module has: the noise acquiring unit is used to obtain the receiving terminal actual noise on the DSL subcarrier; Statistical analysis unit is carried out statistical analysis to described receiving terminal actual noise; And computing unit, be used for determining reference virtual according to the statistical analysis of the receiving terminal actual noise of the receiving terminal actual noise of the described subcarrier that obtains and the described subcarrier that obtains and the relevant parameter that urgent speed reduces machine-processed SOS.

11. broadband network system according to claim 10 is characterized in that, described local side apparatus specifically is Digital Subscriber Line Access Multiplexer DSLAM.

Images