CN100563116C - Utilize the method and system of second generation Very-high-speed Digital Subscriber Line transmission signals - Google Patents

Abstract

The invention discloses a kind of method of utilizing second generation Very-high-speed Digital Subscriber Line transmission signals, this method is enabled the US0 uplink band of VDSL2, and the upper limit of US0 uplink band is overlapped with the lower limit of DS1 band downlink; Adjust the coincide point of the US0 uplink band upper limit and DS1 band downlink lower limit according to the comparative result of the upstream rate of the upstream rate of the transmission signals reality of real-time measurement and downstream rate and expectation and downstream rate.The invention also discloses a kind of system that utilizes second generation Very-high-speed Digital Subscriber Line transmission signals, comprising: the coincide point setting device is used to set the initial value of frequency point of coincide point of the lower limit of the upper limit of US0 uplink band of VDSL2 and DS1 band downlink; The coincide point adjusting device is used for going up the upstream rate of transmission signals and the requirement accent coincide point of downstream rate according to VDSL2.Utilize the present invention, can improve the loop range of VDSL2 when high rate data transmission effectively.

Description

Utilize the method and system of second generation Very-high-speed Digital Subscriber Line transmission signals

Technical field

The present invention relates to the network transmission technology field, be specifically related to a kind of method and system of utilizing second generation Very-high-speed Digital Subscriber Line transmission signals.

Background technology

XDSL (xDigital Subscriber Line, the general designation of various Digital Subscriber Line) technology is through years of development, develop into ADSL2, the ADSL2+ of the present second generation and VDSL2 (the Very-high-bit-rate DSL 2 of renewal from the ADSL of the first generation, second generation Very-high-speed Digital Subscriber Line), the frequency band of its use is increasing gradually, and corresponding bandwidth is also increasing gradually.The following frequency spectrum of the descending use of ADSL and ADSL2 1.1MHz can provide the downstream rate of maximum 8Mbps, and ADSL2+ expands to 2.2MHz with downlink bandwidth, and the downstream rate of maximum 24Mbps can be provided.

VDSL2 be up-to-date also be state-of-the-art xDSL broadband cable communication standard.VDSL2 support voice, video, data, HDTV (High Definition Television, high definition TV) and professional widespread deployment such as interactive game, can help user and operator progressively, flexibly with save into the existing xDSL architecture of local upgrade.VDSL2 even use can provide the speed of the highest up-downgoing symmetry 100Mbps up to the frequency spectrum of 30MHz.

For this reason, industry exploitation in good time and standardization the VDSL2 technology.Different with other several DSL permission selection discrete multitones (DMT) or quadrature amplitude modulation (QAM) technology, VDSL2 can only use the DMT line coding.DMT is a kind of method of the DSL of cutting apart signal, and useful frequency range is divided into a plurality of little frequency ranges.Can be divided into 4096 frequency ranges at most, the spacing of each frequency range is 4kHz or 8kHz.Wherein each frequency range can be as the downlink or uplink transmission.

The VDSL2 standard G.993.2 in the definition the VDSL2 channel frequency spectrum as shown in Figure 1:

Wherein, USX represents the frequency spectrum of up channel, and DSX represents the frequency spectrum of down channel.Each frequency values among Fig. 1 is defined as follows shown in the table 1 in G.993.2:

Table 1:

Because the relation of signal on the subscribers feeder and Route Length, the decay of signal frequency exponentially.Subscribers feeder is long more, and the high-frequency signal decay is big more.So in the prior art, the loop range of VDSL2 when high rate data transmission is usually in a km.In actual applications, the headend equipment of VDSL2 must be near the user, and general and FTTC (Fiber To The Curb, Fiber To The Curb), FTTB technology such as (Fiber To The Building, Fiber-To-The-Building) etc. are used in combination.When the subscribers feeder long enough, so that the signal amplitude in the uplink spectrum decays to below the detection threshold of receiving terminal, just the out of use problem of VDSL2 appears.

Such as, according to the empirical equation of twisted-pair feeder, the cable that calculates model and be AWG26 in the attenuation results of 2.5 kilometers length as shown in Figure 2:

Suppose to adopt 998 spectrum division schemes in the table 1.Be f1=276K, f2=3.75MHz, US0 does not use.The minimum threshold level of receiver is-95dBm0.

As seen from the figure, when frequency was 2.576Mhz, received signal reached-95dBm0.

According to above condition, descending effective bandwidth is 2.576-0.276=2.3Mhz, and up bandwidth is 0.Because of no data feedback channel, communication can not be used.The frequency spectrum of this moment as shown in Figure 3.

Summary of the invention

The purpose of this invention is to provide a kind of method of utilizing second generation Very-high-speed Digital Subscriber Line transmission signals,, improve the loop range of VDSL2 when high rate data transmission to solve the problem that VDSL2 uses on long distance users.

Another object of the present invention provides a kind of system that utilizes second generation Very-high-speed Digital Subscriber Line transmission signals, improves the loop range of VDSL2 when high rate data transmission.

For this reason, the invention provides following technical scheme:

A kind of method of utilizing second generation Very-high-speed Digital Subscriber Line transmission signals, described method comprises:

Enable the US0 uplink band of second generation Very-high-speed Digital Subscriber Line VDSL2, and the upper limit of US0 uplink band is overlapped with the lower limit of DS1 band downlink;

Require to adjust the coincide point of the US0 uplink band upper limit and DS1 band downlink lower limit according to the comparative result of the upstream rate of the upstream rate of the transmission signals reality of real-time measurement and downstream rate and expectation and downstream rate.

Preferably, the initial value of setting described coincide point is the lower limit of the DS1 band downlink divided of medium standard frequency spectrum.

The step that the comparative result of the upstream rate of the transmission signals reality that described basis is measured in real time and the upstream rate of downstream rate and expectation and downstream rate is adjusted the coincide point of the US0 uplink band upper limit and DS1 band downlink lower limit comprises:

Determine transmission signals is expected on the VDSL2 when described coincide point is got initial value upstream rate and downstream rate;

Measure the upstream rate and the downstream rate of transmission signals reality on VDSL2 in real time;

When upstream rate that does not reach expectation when the upstream rate and the downstream rate of described reality and downstream rate, adjust described coincide point.

Describedly determine that when described coincide point is got initial value the upstream rate of transmission signals expectation on the VDSL2 and the step of downstream rate comprise:

The signal to noise ratio of each subcarrier in each frequency range on VDSL2 when measurement is got initial value in described coincide point;

Determine the bit load table of each frequency range according to described signal to noise ratio;

Calculate upstream rate and the downstream rate that VDSL2 goes up the transmission signals expectation according to described bit load table.

Describedly determine that according to signal to noise ratio the step of the bit load table of each frequency range comprises:

Utilize formula $b_i=w\log (1+{\left(\frac{S}{N}\right)}_i)$ Calculate the bit number that each subcarrier in each frequency range can load,

Wherein, i is the numbering of subcarrier in the frequency range,

Bi is the bit number that i subcarrier loads,

(S/N) _iBe that i subcarrier loads the signal to noise ratio that records,

W is the bandwidth of each subcarrier;

Determine the bit loading table of each frequency range according to the bit number that calculates.

The step of the described coincide point of described adjustment comprises:

When the downstream rate of the reality downstream rate greater than expectation, and actual upstream rate moves described coincide point during less than the upstream rate of expectation to the high direction of frequency;

When the downstream rate of the reality downstream rate less than expectation, and actual upstream rate moves described coincide point during greater than the upstream rate of expectation to the low direction of frequency;

The downstream rate that equals to expect when the downstream rate of reality, and actual upstream rate is adjusted described coincide point according to Carrier Requirements during greater than the upstream rate of expectation.

The described step of adjusting described coincide point according to Carrier Requirements comprises:

Do not adjust described coincide point, and guaranteeing under the prerequisite that downstream rate meets the demands, maximum upstream rate is provided; Perhaps

Adjust described coincide point, make the upstream rate maximization, or make the downstream rate maximization, or upstream rate and downstream rate are all maximized.

The described coincide point of described adjustment comprises all maximized step of upstream rate and downstream rate:

Redefine described coincide point according to upstream bits load table and downstream bits load table.

Described method also comprises:

If actual upstream rate is less than the upstream rate of expectation, and actual downstream rate then sends alarm information less than the downstream rate of expectation.

Described method also comprises:

Local side sends the value of adjusted coincide point to the modulator-demodulator of far-end by the special test channel.

The US0 uplink band of second generation Very-high-speed Digital Subscriber Line (VDSL2) is enabled by a kind of system that utilizes second generation Very-high-speed Digital Subscriber Line transmission signals, described system, and described system comprises:

The coincide point setting device is used to set the initial value of frequency point of coincide point of the lower limit of the upper limit of US0 uplink band of second generation Very-high-speed Digital Subscriber Line VDSL2 and DS1 band downlink;

The coincide point adjusting device is used for according to the upstream rate of the transmission signals reality of measurement and the upstream rate of downstream rate and expectation and the comparative result of downstream rate are adjusted described coincide point in real time.

Described system also comprises:

Expected rate is determined device, links to each other with described coincide point setting device, is used to determine when described coincide point is got initial value the upstream rate and the downstream rate of transmission signals expectation on the VDSL2, and sends the expected rate of determining to described coincide point adjusting device.

Described expected rate determines that device comprises:

The snr measurement unit is used to measure when described coincide point is got initial value on the VDSL2 signal to noise ratio of each subcarrier in each frequency range;

The expected rate computing unit is used for going up upstream rate and the downstream rate that transmission signals is expected according to described snr computation VDSL2.

Described coincide point adjusting device comprises:

The actual speed rate measuring unit is used for the upstream rate and the downstream rate of measurement transmission signals reality on VDSL2 in real time;

Comparing unit is used for upstream rate and downstream rate that the upstream rate of the reality that more described actual speed rate measuring unit measures and downstream rate and described expected rate are determined the expectation that device is determined;

Adjust performance element, link to each other, be used for adjusting described coincide point according to the comparative result of described comparing unit with described coincide point setting device.

Described coincide point adjusting device also comprises:

Adjust strategy the unit is set, link to each other, be used to set and adjust performance element the required adjustment strategy of coincide point adjustment with described adjustment performance element.

By above technical scheme provided by the invention as can be seen, the present invention provides the upward signal passage of VDSL2 on long distance users line by enabling US0 frequency range in the VDSL2 frequency spectrum as up channel; And the upper limit of US0 frequency range is overlapped with the lower limit of DS1 frequency range, made full use of the frequency spectrum resource of VDSL2.Simultaneously, according to the requirement adjustment US0 frequency range upper limit of uplink and downlink speed and the coincide point of DS1 frequency range lower limit, thereby the speed of the uplink and downlink channel that can obtain expecting has improved the loop range of VDSL2 when high rate data transmission effectively.

Description of drawings

Fig. 1 is the spectrogram of the VDSL2 channel of definition in the existing VDSL2 standard 993.2;

Fig. 2 is that current version is the decay schematic diagram of the cable of AWG26 2.5 kilometers length;

Fig. 3 is the spectrogram of VDSL2 on the long distance users line;

Fig. 4 is the realization flow figure of a preferred embodiment of the inventive method;

Fig. 5 is the spectrogram of the VDSL2 of correspondence among the present invention;

Fig. 6 is the schematic diagram of adjusting coincide point among the present invention, reducing the frequency spectrum of DS1;

Fig. 7 is the schematic diagram of adjusting coincide point among the present invention, increasing the frequency spectrum of DS1;

Fig. 8 is the theory diagram of a preferred embodiment of system of the present invention.

Embodiment

Core of the present invention is to enable US0 frequency range in the VDSL2 frequency spectrum as up channel, and the upper limit of US0 frequency range is overlapped with the lower limit of DS1 frequency range, when carrying out the signal transmission, the coincide point of the US0 frequency range upper limit and DS1 frequency range lower limit is adjusted in the requirement of going up the upstream rate of transmission signals and downstream rate according to VDSL2 in real time, makes the speed of the uplink and downlink channel of VDSL2 reach the rate value of expectation as far as possible.

In order to make those skilled in the art person understand the present invention program better, the present invention is described in further detail below in conjunction with drawings and embodiments.

With reference to Fig. 4, Fig. 4 shows the realization flow of a preferred embodiment of the inventive method, may further comprise the steps:

Step 401: as up channel, and the upper limit of US0 frequency range is overlapped with the lower limit of DS1 frequency range the US0 frequency range of VDSL2.

Because VDSL2 standard G.993.X intermediate frequency spectrum has defined US0 (upward signal) frequency range, but this frequency range is not used at present.Therefore, the present invention enables the US0 frequency range for solving the problem of VDSL2 no up signalling channel on long distance users line.And, the upper limit of US0 frequency range is overlapped with the lower frequency limit point f1 of DS1 frequency range, and this coincide point can be adjusted as requested in real time in order to make full use of frequency spectrum resource.Based on this use, the frequency spectrum of corresponding VDSL2 as shown in Figure 5 among the present invention.

Step 402: the initial value of setting coincide point is the lower limit of the DS1 frequency range of medium standard frequency spectrum division, i.e. the lower frequency limit point f1 of DS1 frequency range in the existing standard.

Certainly, the initial value that also can set coincide point is that the lower limit of US0 frequency range is to any frequency between the upper limit of DS1 frequency range.

Step 403: determine transmission signals is expected on the VDSL2 when coincide point is got initial value upstream rate and downstream rate.

Step 404: upstream rate and the downstream rate of measuring transmission signals reality on VDSL2 in real time.

Step 405: judge the upstream rate of the reality of measuring and upstream rate and the downstream rate whether downstream rate reaches expectation.If reach, then enter step 406; Otherwise, enter step 407.

Local side is got at f1 under the prerequisite of initial value according to the bit load table that actual measurement obtains, the up-downgoing speed that contrast is actual and the up-downgoing speed of requirement.If reach requirement, the value of keeping f1 is constant.If do not meet the demands, then need to adjust the value of f1.

Step 406: behind the delay scheduled time, return step 404, measure next time.Its objective is channel is carried out the dynamic real-time adjustment, this scheduled time can be provided with according to actual needs.

Step 407: the upstream rate and the requirement adjustment US0 frequency range upper limit of downstream rate and the coincide point of DS1 frequency range lower limit that go up transmission signals according to VDSL2.

In above-mentioned steps 403, need determine transmission signals is expected on the VDSL2 when coincide point is got initial value upstream rate and downstream rate, below this is elaborated.

For the speed of the up-downgoing channel that obtains expecting, get at f1 under the prerequisite of initial value, require at first to obtain the signal to noise ratio of each frequency range.

For this reason, in initialization procedure, the upper limit of setting the US0 frequency range overlaps with the lower limit of DS1 frequency range, and after this coincide point value was f1, the modulator-demodulator of far-end sent whole US0, US1, and the signal of US2 frequency band, the confession local side is tested.Local side obtains the SNR (signal to noise ratio) of each subcarrier in this frequency range through test.Equally, the modulator-demodulator of local side sends DS1, and the signal of DS2 frequency band is for remote test.Far-end obtains the SNR of each subcarrier in this frequency range through test.The method of measurement SNR has multiple in the prior art, can select for use as required.

Like this, can obtain the SNR that VDSL2 goes up each subcarrier in each frequency range.Then, the SNR according to each subcarrier records, utilize formula:

$b_i=w\log (1+{\left(\frac{S}{N}\right)}_i)---\left(1\right)$

Calculate the summation of the bit loading number of each subcarrier in the whole frequency.Because of on long distance users line, DS2, US1, the decay of US2 frequency band signals is big, exceeds the minimum zone of reception, can think that the bit number that these 3 frequency ranges load is 0.Therefore, only need calculate US0 respectively, the bit number that each subcarrier in the DS1 frequency range can load gets final product.

In the formula, i is the numbering of each frequency band sub-carriers, promptly satisfies $\mathrm{floor}\left(\frac{f_{\mathrm{OL}}}{4.3125k}\right)\≤i\≤\mathrm{floor}\left(\frac{f_1}{4.3125k}\right),$ Floor represents to round downwards;

b _iRepresent the bit number that i subcarrier loads;

(S/N) _iRepresent that i subcarrier loads the signal to noise ratio that records;

W is the bandwidth of each subcarrier, 4.3125KHz.

After obtaining the bit load table of last each frequency range of VDSL2, can calculate upstream rate and the downstream rate that VDSL2 goes up the transmission signals expectation according to the bit load table.

Such as, calculate up bit loading number and be $b_{\mathrm{up}}=\underset{\mathrm{US}0}{\mathrm{\Σ}}\mathrm{bi}+\underset{\mathrm{US}1}{\mathrm{\Σ}}\mathrm{bi}+\underset{\mathrm{US}2}{\mathrm{\Σ}}\mathrm{bi},$ This value is uplink speed.

Descending bit loading number is $b_{\mathrm{down}}=\underset{\mathrm{DS}1}{\mathrm{\Σ}}\mathrm{bi}+\underset{\mathrm{DS}2}{\mathrm{\Σ}}\mathrm{bi},$ This value is downlink transfer speed.

In the VDSL2 signals transmission, the up-downgoing channel speed that contrast is actual and the up-downgoing channel speed of expectation, if reach requirement, i.e. actual uplink speed equates with the expectation upstream rate; Actual downstream speed equates that with the expectation downstream rate value of frequency point of then keeping coincide point is constant; If do not reach requirement, then need adjust with the position of this coincide point, that is to say the value of frequency point that will adjust coincide point, thereby adjust the spectrum width of uplink band US0 and band downlink DS1.

Describe among the present invention adjustment process below in detail to the coincide point of the lower limit of the upper limit of US0 frequency range and DS1 frequency range.

According to the up-downgoing channel speed of actual measurement and the comparative result of the up-downgoing channel speed of expectation, following several situation can be arranged:

1. when the downstream rate of actual downstream rate greater than expectation, and actual upstream rate moves coincide point during less than the upstream rate of expectation to the high direction of frequency.

If the upstream rate of actual measurement is less than the upstream rate of expectation, and downstream rate is greater than the downstream rate of expectation, then with the part of downstream rate greater than descending expected rate, distribute to up channel, a part that is about to join with US0 in the DS1 frequency spectrum gives US0, as shown in Figure 6, wherein, Fig. 6 (a) is f ₁Schematic diagram before adjusting, Fig. 6 (b) is f ₁Adjusted schematic diagram.Among Fig. 6, the speed of up channel promotes because of uplink spectrum increases.

During specific implementation, the amplitude that coincide point is adjusted can come to determine as required.Such as, calculate downstream rate earlier and meet the desired the spectrum width that can save after the downstream rate, this part spectrum width is allocated to US0 once.Can also set a fixing adjusting range, according to this amplitude adjust when adjusting at every turn.Still do not meet the demands if adjust the back upstream rate, wait measure next time after, guaranteeing to continue to dwindle the spectrum width of DS1 again under the prerequisite that downstream rate meets the demands, adjust accordingly.

Suppose that DS1 has 256 subcarriers, the little low carrier wave of numbering respective frequencies.If 200 subcarriers of descending needs are then distributed to descending subcarrier from numbering 1 to 200, be the saved spectrum width of DS1 and number 201 to 256 subcarrier, this part spectrum width can be allocated to US0 and use.

Upstream rate after the lifting is compared with the upstream rate of expectation, have three kinds may: less than the speed, the speed that equals to expect of expectation, greater than the speed of expectation.

At these three kinds possibilities, can handle accordingly as required.Such as:

(1) when actual uplink speed less than expectation during upstream rate, to ALM.Be correspondingly processed by system, as reducing upstream rate or downstream rate.

(2) when actual uplink speed equates with the expectation upstream rate, be optimal situation, the value of preserving f1 gets final product.

(3), can further process during upstream rate greater than expectation when actual uplink speed according to the requirement of operator.As not doing further processing, use and preserve the f1 value; Or, strive for bigger downstream rate guaranteeing minimum upstream rate, promptly forward the upstream rate that upstream rate equals to expect to, and downstream rate is greater than the handling process of the downstream rate of expectation.

2. when the downstream rate of actual downstream rate less than expectation, and actual upstream rate moves coincide point during greater than the upstream rate of expectation to the low direction of frequency.

If the upstream rate of actual measurement is greater than the upstream rate of expectation, and downstream rate is less than the downstream rate of expectation, then with a part of dispensing down channel of upstream rate greater than up expected rate, a part that is about to join with DS1 in the US0 frequency spectrum gives DS1, as shown in Figure 7, wherein, Fig. 7 (a) is f ₁Schematic diagram before adjusting, Fig. 7 (b) is f ₁Adjusted schematic diagram.In Fig. 7, the speed of down channel promotes because of downstream spectrum increases.

Equally, during specific implementation, the amplitude that coincide point is adjusted can come to determine as required.Such as, calculate upstream rate earlier and meet the desired the spectrum width that can save after the upstream rate, this part spectrum width is allocated to DS1 once.Can also set a fixing adjusting range, according to this amplitude adjust when adjusting at every turn.Still do not meet the demands if adjust the back upstream rate, wait measure next time after, guaranteeing to continue to dwindle the spectrum width of US0 again under the prerequisite that upstream rate meets the demands, adjust accordingly.

Suppose that US0 has 256 subcarriers, the little low carrier wave of numbering respective frequencies.If 200 subcarriers of up needs are then distributed to up subcarrier from numbering 1 to 200, be the saved spectrum width of US0 and number 201 to 256 subcarrier, this part spectrum width can be allocated to DS1 and use.

Downstream rate after the lifting is compared with the downstream rate of expectation, have three kinds may: less than the speed, the speed that equals to expect of expectation, greater than the speed of expectation.

(1) when actual downstream speed less than expectation during downstream rate, to ALM.Be correspondingly processed by system, as reducing upstream rate or downstream rate.

(2) when actual downstream speed equates with the expectation downstream rate, be optimal situation.The value of preserving f1 gets final product.

(3), can further process during downstream rate greater than expectation when actual downstream speed according to the requirement of operator.As not doing further processing, use and preserve the f1 value; Or, strive for bigger upstream rate guaranteeing minimum downstream rate, promptly forward the downstream rate that downstream rate equals to expect to, and upstream rate is greater than the handling process of the upstream rate of expectation.

3. the downstream rate that equals to expect when actual downstream rate, and actual upstream rate is adjusted coincide point according to Carrier Requirements during greater than the upstream rate of expectation.Such as, can uncomfortable bulk wight chalaza, and guaranteeing under the prerequisite that downstream rate meets the demands, maximum upstream rate is provided; Perhaps adjust coincide point, upstream rate and downstream rate are all maximized.Concrete adjustment process is as follows:

(1) guaranteeing under the prerequisite that upstream rate meets the demands, striving for maximum downstream rate.Need not adjust f1 this moment.

(2) uplink and downlink speed is all maximized.At this moment, need readjust f1.During specific implementation, can total bit number addition of upstream bits load table and downstream bits load table be removed 2 again by local side.Can obtain the value of f1 by mean value and bit load table.When averaging, as fractional part occurs, can adopt the method that rounds downwards.The result who obtains like this can make the actual speed rate of uplink and downlink only differ several bits than desired value.

Certainly, the present invention is not limited to several modes of above-mentioned adjustment to coincide point, can set other adjustment modes according to application need, as long as make actual uplink speed and downstream rate meet the desired rate value as much as possible.

Under the situation that transmission signals speed worsens most, promptly Shi Ce upstream rate is less than the upstream rate of expectation, and downstream rate can be correspondingly processed by system to ALM, as reducing upstream rate or downstream rate during also less than the downstream rate of expectation.

After coincide point adjusted, local side can send the value of adjusted coincide point to the modulator-demodulator of far-end by the special test channel.

With reference to Fig. 8, Fig. 8 shows the theory diagram of a preferred embodiment of system of the present invention:

In this embodiment, system of the present invention comprises: coincide point setting device S1, coincide point adjusting device S2.Wherein, coincide point setting device S1 is used to set the initial value of frequency point of coincide point of the lower limit of the upper limit of US0 frequency range of VDSL2 and DS1 frequency range; Coincide point adjusting device S2 is used for transferring described coincide point according to the upstream rate of the last transmission signals of VDSL2 and the requirement of downstream rate.

Illustrate in the description to the inventive method in front, in the present invention, need enable the US0 frequency range of untapped VDSL2 in the existing standard, as up channel, and the upper limit of US0 frequency range is overlapped with the lower limit of DS1 frequency range it.System of the present invention is equally based on this thought.Certainly, the initial value of the frequency at this coincide point place can be provided with arbitrarily between the upper limit of the lower limit of US0 frequency range and DS1 frequency range.Such as, for the computational process in the simple realization, the initial value that can set this coincide point is the lower limit of the DS1 frequency range of medium standard frequency spectrum division.

In order can reasonably to adjust coincide point according to the actual speed rate of the last transmission signals of VDSL2, the distance that VDSL2 can be transmitted is longer, in the present invention, can go up upstream rate and the requirement adjustment US0 frequency range upper limit of downstream rate and the coincide point of DS1 frequency range lower limit of transmission signals according to VDSL2.For this reason, in this embodiment, determine that by expected rate device S3 determines transmission signals is expected on the VDSL2 when coincide point is got initial value upstream rate and downstream rate, and send the expected rate of determining to coincide point adjusting device S2.Like this, coincide point adjusting device S2 just can come coincide point is correspondingly adjusted according to upstream rate and downstream rate that this desired value and actual measurement obtain.

Expected rate determines that device S3 comprises: snr measurement cell S 31 and expected rate computing unit S32.Wherein, snr measurement cell S 31 is used to measure when described coincide point is got initial value on the VDSL2 signal to noise ratio of each subcarrier in each frequency range; Expected rate computing unit S32 is used for going up according to described snr computation VDSL2 the upstream rate and the downstream rate of transmission signals expectation.

Need to prove, snr measurement cell S 31 comprises local side snr measurement unit and far-end snr measurement unit, respectively local side and far-end to each uplink band on the VDSL2 when coincide point is got initial value in each subcarrier noise when in each band downlink the signal to noise ratio of each subcarrier measure.Concrete measuring process can not repeat them here with reference to the front to the description in the inventive method.

Coincide point adjusting device S2 comprises: actual speed rate measuring unit S21, comparing unit S22 and adjustment performance element S23.Wherein, actual speed rate measuring unit S21 is used for measuring in real time the upstream rate and the downstream rate of transmission signals reality on VDSL2; Comparing unit S22 is used for upstream rate and the downstream rate that the upstream rate of the reality that comparison actual speed rate measuring unit S21 measures and downstream rate and described expected rate are determined the expectation that device is determined; Adjusting performance element S23 is used for adjusting described coincide point according to the comparative result of comparing unit S22.

In the VDSL2 signals transmission, measure the upstream rate and the downstream rate of transmission signals reality on VDSL2 in real time by actual speed rate measuring unit S21, comparing unit S22 determines that to this measurement result and expected rate the upstream rate and the downstream rate of the expectation that device S3 determines compare, and comparative result can have following several situation:

1. Shi Ji downstream rate is greater than the downstream rate of expectation, and actual upstream rate is during less than the upstream rate of expectation;

2. Shi Ji downstream rate is less than the downstream rate of expectation, and actual upstream rate is during greater than the upstream rate of expectation;

3. the Shi Ji downstream rate downstream rate that equals to expect, and actual upstream rate is greater than the upstream rate of expectation;

4. Shi Ji upstream rate is less than the upstream rate of expectation, and downstream rate is also less than the downstream rate of expecting;

5. Shi Ji upstream rate is greater than the upstream rate of expectation, and downstream rate is also greater than the downstream rate of expecting.

Under above-mentioned the 1st to 4 situation, upstream rate or downstream rate do not meet the desired upstream rate or downstream rate, at this moment, need adjust coincide point, so that upstream rate and downstream rate reach optimum as far as possible.Under the 5th situation, uplink and downlink speed all meets the demands, and at this moment, does not need to adjust the position of coincide point.

Can be with reference to the description in the inventive method of front under the situation that upstream rate or downstream rate do not meet the demands to the adjustment process of coincide point.Certainly the present invention also is not limited to previously described several adjustment mode.In actual applications, also can set other adjustment modes, as long as make actual uplink speed and downstream rate meet the desired rate value as much as possible.

The different application merchant formulates the adjustment strategy of oneself for convenience, can also in system of the present invention, be provided with one and adjust tactful setting device S4, this device links to each other with adjustment performance element S23, is used to set adjust performance element to the required adjustment strategy of coincide point adjustment.Like this,, just can set corresponding adjustment strategy, increase the flexibility of system applies of the present invention effectively according to the needs of oneself at different applied environments and for different application merchants.

Though described the present invention by embodiment, those of ordinary skills know, the present invention has many distortion and variation and do not break away from spirit of the present invention, wish that appended claim comprises these distortion and variation and do not break away from spirit of the present invention.

Claims (15)

1, a kind of method of utilizing second generation Very-high-speed Digital Subscriber Line transmission signals is characterized in that, described method comprises:

Enable the US0 uplink band of second generation Very-high-speed Digital Subscriber Line (VDSL2), and the upper limit of US0 uplink band is overlapped with the lower limit of DS1 band downlink;

Adjust the coincide point of the US0 uplink band upper limit and DS1 band downlink lower limit according to the comparative result of the upstream rate of the upstream rate of the transmission signals reality of real-time measurement and downstream rate and expectation and downstream rate.

2, method according to claim 1 is characterized in that, described method also comprises:

The initial value of setting described coincide point is the lower limit of the DS1 band downlink of medium standard frequency spectrum division.

3, method according to claim 2, it is characterized in that the step that the comparative result of the upstream rate of the transmission signals reality that described basis is measured in real time and the upstream rate of downstream rate and expectation and downstream rate is adjusted the coincide point of the US0 uplink band upper limit and DS1 band downlink lower limit comprises:

Determine transmission signals is expected on the VDSL2 when described coincide point is got initial value upstream rate and downstream rate;

Measure the upstream rate and the downstream rate of transmission signals reality on VDSL2 in real time;

When upstream rate that does not reach expectation when the upstream rate and the downstream rate of described reality and downstream rate, adjust described coincide point.

4, method according to claim 3 is characterized in that, describedly determines that when described coincide point is got initial value the upstream rate of transmission signals expectation on the VDSL2 and the step of downstream rate comprise:

The signal to noise ratio of each subcarrier in each frequency range on VDSL2 when measurement is got initial value in described coincide point;

Determine the bit load table of each frequency range according to described signal to noise ratio;

Calculate upstream rate and the downstream rate that VDSL2 goes up the transmission signals expectation according to described bit load table.

5, method according to claim 4 is characterized in that, describedly determines that according to signal to noise ratio the step of the bit load table of each frequency range comprises:

Utilize formula $b_i=w\log (1+{\left(\frac{S}{N}\right)}_i)$ Calculate the bit number that each subcarrier in each frequency range can load, wherein,

I is the numbering of subcarrier in the frequency range,

Bi is the bit number that i subcarrier loads,

(S/N) _iBe that i subcarrier loads the signal to noise ratio that records,

W is the bandwidth of each subcarrier;

Determine the bit loading table of each frequency range according to the bit number that calculates.

6, method according to claim 3 is characterized in that, the step of the described coincide point of described adjustment comprises:

When the downstream rate of the reality downstream rate greater than expectation, and actual upstream rate moves described coincide point during less than the upstream rate of expectation to the high direction of frequency;

When the downstream rate of the reality downstream rate less than expectation, and actual upstream rate moves described coincide point during greater than the upstream rate of expectation to the low direction of frequency;

The downstream rate that equals to expect when the downstream rate of reality, and actual upstream rate is adjusted described coincide point according to Carrier Requirements during greater than the upstream rate of expectation.

7, method according to claim 6 is characterized in that, the described step of adjusting described coincide point according to Carrier Requirements comprises:

Do not adjust described coincide point, and guaranteeing under the prerequisite that downstream rate meets the demands, maximum upstream rate is provided; Perhaps

Adjust described coincide point, make the upstream rate maximization, or make the downstream rate maximization, or upstream rate and downstream rate are all maximized.

8, method according to claim 7 is characterized in that, the described coincide point of described adjustment comprises all maximized step of upstream rate and downstream rate:

Redefine described coincide point according to upstream bits load table and downstream bits load table.

9, according to right with requiring 6 described methods, it is characterized in that described method also comprises:

If actual upstream rate is less than the upstream rate of expectation, and actual downstream rate then sends alarm information less than the downstream rate of expectation.

10, method according to claim 1 is characterized in that, described method also comprises:

Local side sends the value of adjusted coincide point to the modulator-demodulator of far-end by the special test channel.

11, a kind of system that utilizes second generation Very-high-speed Digital Subscriber Line transmission signals is characterized in that, the US0 uplink band of second generation Very-high-speed Digital Subscriber Line (VDSL2) is enabled by described system, and described system comprises:

The coincide point setting device is used to set the initial value of frequency point of coincide point of the lower limit of the upper limit of US0 uplink band of VDSL2 and DS1 band downlink;

The coincide point adjusting device is used for according to the upstream rate of the transmission signals reality of measurement and the upstream rate of downstream rate and expectation and the comparative result of downstream rate are adjusted described coincide point in real time.

12, system according to claim 11 is characterized in that, described system also comprises:

Expected rate is determined device, links to each other with described coincide point setting device, is used to determine when described coincide point is got initial value the upstream rate and the downstream rate of transmission signals expectation on the VDSL2, and sends the expected rate of determining to described coincide point adjusting device.

13, system according to claim 12 is characterized in that, described expected rate determines that device comprises:

The snr measurement unit is used to measure when described coincide point is got initial value on the VDSL2 signal to noise ratio of each subcarrier in each frequency range;

The expected rate computing unit is used for going up upstream rate and the downstream rate that transmission signals is expected according to described snr computation VDSL2.

14, system according to claim 12 is characterized in that, described coincide point adjusting device comprises:

The actual speed rate measuring unit is used for the upstream rate and the downstream rate of measurement transmission signals reality on VDSL2 in real time;

Comparing unit is used for upstream rate and downstream rate that the upstream rate of the reality that more described actual speed rate measuring unit measures and downstream rate and described expected rate are determined the expectation that device is determined;

Adjust performance element, link to each other, be used for adjusting described coincide point according to the comparative result of described comparing unit with described coincide point setting device.

15, system according to claim 14 is characterized in that, described coincide point adjusting device also comprises:

Adjust strategy the unit is set, link to each other, be used to set and adjust performance element the required adjustment strategy of coincide point adjustment with described adjustment performance element.

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