Research And Application Of VDSL2 Technology

In 2006, ITU launched VDSL2, a new generation of xDSL technology, which is currently very hot in the field of xDSL technology. This paper will make a study of VDSL2 technology and application from the following three aspects, in order to improve the performance of VDSL2 systems.First of all, according to the use of frequency bands and transmit power spectral density specified in the latest VDSL2 standard, this paper shall do research and simulation on noise to the VDSL2 systems, the characteristics of twisted-pair transmission channel, RFI-notch and tone blackout, and maximum rate reaching of VDSL2 when using different band plan and the test loops. So that it provides theoretical reference to network cabling, business open, standards improving, equipment manufacturing , RFI-notch and tone blackout using of VDSL2.Secondly, a study on power back-off algorithm. The crosstalk between the cables of the same bunch of twisted-pair is a major factor affecting VDSL2 rate, so we need back-off the power of VDSL2. Power back-off to VDSL2 is divided into upstream power back-off (UPBO) and downstream power back-off (DPBO). This paper shall make a theoretical study on the existing 7 UPBO and DPBO algorithms, and through simulation, analyzing performance of the said algorithms, and introduce the optimization method of configuration parameters of standard specifies UPBO algorithm. At the same time, contacting the theory of PBO algorithm and practical networking environment, this paper shall study improvements on the current standard UPBO and DPBO algorithms, and analyze three kinds of performance of the said algorithms through simulation, So that providing reference to standards improving.Thirdly, a study on retransmission technology. The latest VDSL2 standard uses FEC and interleaver to resist various kinds of pulse interference, so as to reduce the error rate. However, a good anti-noise capacity needs a large interleaver, while getting a long delay, so it can't meet the needs of different users. The use of retransmission technology can solve the above problems better. This paper shall study on HARQ-VDSL2 system principle, retransmission realization program of the PMS-TC layer and implementation program of HARQ-VDSL2 system. And compare the performance of HARQ-VDSL2 system to FEC-VDSL2. Through theoretical analysis and simulation, this paper shall come to a conclusion which is of significant referential value.