On modelling local loops for digital subscriber line (DSL) connectivity

Abstract

This paper is posed on the single point subscriber line modeling problem, consisting of two main paragraphs out of the one for introduction andof that for remarks and suggestions for next works. In the second paragraph, a brief report is made on network topology and characteristics of  local  loop  model  obtaining  from  transmission  line  theory  and  electrical  characteristics  of twisted pair segments. Being of distributed nature,parameters of local loop models are not found to  be  successfully  estimated  by  common  techniques  with  the  use  of  direction  time  response (TDR)  in  system  identification  theory.  However,  two algorithms  well  known  on  the  basis  of method of direction estimate (MODE) namely MODE-WRELAX and MODE-type  are briefly resumed  in the  second  paragraph.  In  the  third  one,  a  method  is proposed  on  the  basis  of  two dimensional  Poisson  Momentum  Function  which  transforms  signals  on  the  both  sides  of  the system,  i.e.  input and output  sides,  to  spatial-time  domain  for  direction  -of-arrival  estimation. The  fact  behind  the  spatial-time  domain  is  that  time-frequency  space  leading  to  the  usage  of MODE-type  algorithm  for  separation  of  different  reflections  in  frequency  domain.  In  the  last paragraph, three different comments on the proposedmethod of supplying measurements data by Poisson  Momentum  Function  for  estimation  purpose  and  suggestions  for  further  study  to  be carried out.