Method and device for shortening link establishing time, and local end equipment

Abstract

The invention discloses a method for shortening link establishing time. The method comprises the steps: determining that when historical far-end crosstalk data of an initial line for a crosstalk elimination line accords with a first preset rule, taking the historical far-end crosstalk data as first far-end crosstalk data of the initial line for the crosstalk elimination line in a current link establishing state; establishing a link according to the first far-end crosstalk data. The initial line is a line corresponding to current link establishment, and the crosstalk elimination line is a line acting on the initial line during current link establishment. The invention also discloses a device for shortening link establishing time, and also local end equipment.

Description

technical field [0001] The invention relates to network communication technology, in particular to a method for shortening the link establishment time, its device, and central office equipment. Background technique [0002] The second generation of very high-speed digital subscriber loop (VDSL2, Very-high-bit-rateDigitalSubscriberloop) is one of the "last mile" mainstream copper wire access technologies, using discrete multi-tone method to modulate data in different The transmission is carried out on the sub-carrier, and the spectral bandwidth up to 30MHz can be used. Therefore, the VDSL2 technology has the advantages of higher transmission rate, longer transmission distance and optimal network utilization. But, because the frequency band that described VDSL2 technology uses is higher, cause digital subscriber line (DSL, Digital Subscriber Line) inter-pair crosstalk, that is, DSL crosstalk problem is relatively prominent, compared with the bandwidth of single-line pair VDSL2...

AI Technical Summary

Problems solved by technology

But, because the frequency band that described VDSL2 technology uses is higher, cause digital subscriber line (DSL, Digital Subscriber Line) inter-pair crosstalk, that is, DSL crosstalk problem is relatively prominent, compared with the bandwidth of single-line pair VDSL2 access, multi-line pair When VDSL2 is connected, the bandwidth of each line pair drops very obviously. Therefore, the DSL crosstalk problem has become the main factor of VDSL2 performance.

[0003] The DSL crosstalk is divided into near-end crosstalk (NEXT, Near-endCrosstalk) and far-end crosstalk (FEXT, Far-endCrosstalk); wherein, the FEXT is that the transmission signal of the interfering line pair starts from the interfering line pair and is coupled to the interfered After the line pair, continue to propagate along the disturbed line pair until it propagates to the "far-end" receiving end of the disturbed line pair; the NEXT is that the transmitted signal of the disturbing line pair starts from the disturbing line pair and is coupled to the disturbed line pair , and then transmitted to the "near-end" receiving end of the disturbed line pair; for the DSL crosstalk, the FEXT is the interference between uplink signals of different line pairs, or between downlink signals of different line pairs; and Described NEXT is the interference between the uplink signal and the downlink signal of different wire pairs; Since the VDSL2 technology adopts the frequency division multiplexing (FDM, Frequency Division Multiplexing) mode, the transmission signal of the interfering wire pair and the received signal of the interfered wire pair use The frequency bands are different, so the NEXT can be eliminated or greatly reduced by the filter; however, the frequency of the FEXT signal from the interfering line pair is the same as the normal received signal of the disturbed line pair, so the FEXT cannot Eliminated by the filter; further, because the transmission distance of the VDSL technology is shorter and the frequency band used is higher, the FEXT problem in the VDSL2 technology is more serious than other DSL technologies, therefore, the FEXT has become an influence on VDSL2 The main factors of the performance of the technology, for example, the FEXT will cause the VDSL system signal-to-noise ratio corresponding to the VDSL technology to decrease, the line transmission rate will decrease or the bit error rate will increase or even drop the line, etc., which will seriously affect the performance of the VDSL system. Stability and User Experience

[0004] In order to completely and fundamentally eliminate the impact of FEXT on VDSL2 technology, the International Telecommunication Union Telecommunication Standardization Organization (ITU-T, ITU Telecommunications Standardization Sector) has launched a technical standard for far-end crosstalk elimination, namely the G993.5 (G.vector) standard; The vectoring (Vectoring) technology in the said G993.5 standard can specifically solve the FEXT problem in the VDSL2 technology line, and then improve the line performance of the VDSL2 technology of the multi-wire pair; The process of collecting wrong samples and estimating inter-pair interference leads to an increase in the link establishment time for customer premises equipment (CPE). Therefore, a solution is urgently needed to eliminate the impact of FEXT on VDSL2 technology. At the same time, reduce the link building time for the client device

Images