Common Mode Transmission And Impulse Noise In Broadband Access Network

Currently DSL technology is one of the main broadband access methods, whichis developing along with the expansion of broadband service, in order to meet therequirement of customers, the transmission data rate can be boosted by reducing theloop distance or extending the effective spectrum. Right now China Telecom andChina Unicom have a lot twisted pair resources, so relying on such resources to gethigher data rate becomes one of the most suitable broadband access way. Based uponthe previous channel in order to improve the data transmission rate, increasing thenumber of channel is one of the suitable solutions, in addition, impulse noise has thenegative impact on the quality of broadband access. This paper carries out theresearch on the relevant problems.Firstly this paper analyses a brand new multi-transmission line theory, theprinciple is to introduce the common-mode channel into the differential-modechannel of the current twisted pair, for example, a binder owning2N lines can beregarded as the hybrid of N×N differential mode channel and (2N-1)×(2N-1)commonmode channel, so the data rate of the entire system can be boosted a lot, the paper also gives theload configuration of transmission and reception in the MIMO model. Besides the characteristicresistance can be used to load configuration of the binder, which can be required through thevarious physical parameters from RLCG model, so the MIMO transmission model can beestablished over the binder. In the end, the paper compares the differential-mode channelfrom MTL theory with the actual measurement channel from France Telecom,proving the validity of the common-mode channel.Besides the time and spectrum properties of the impulse noise is also discussedin the paper, a mathematical model for generating the impulse noise of the DSLaccording to the amplitude, duration and interval is proposed, the parameters of themodel is mainly from the stochastic analysis of the measuring data of BritishTelecom and Deutschland Telecom. Upon the mathematical model of impulse noisethe paper proposes one simulation method, the simulation results are close to thetheorectical expectation of probability distribution of impulse range and powerspectrum, confirming the generated noise meets the time and spectrum property ofDMT environment, validating the proposed mathematical model of impulse noise. Furthermore, a lot impulse noise data is obtained through computer simulation,the channel capacity can be computed by considering the impact of impulse noise invarious channels, so the effect of impulse noise on the data transmission is estimated.