Analysis And Solutions Of The Problem On Long-distance ADSL

ADSL plays an important role of the development of telecommunication as a main product of broad-band business in terms of its advantage of mature technology, high bandwidth and making full use of existing Telephone line resource. By the end of year 2007, shanghai telecom has more than two million users. But with the development of broad-band business during these years, some issues occur in the real application, especially in the rural area where is far away from the terminals and is called the"blind zone"in ADSL development, the ADSL users complain for neither able to active the device nor meeting break frequently after reluctant successful installation.Up to now, ADSL2+ technology is becoming the main solution to the long-distance ADSL users. By changing ADSL card to ADSL2+ card, the use condition is expected to be will improved.This takes some effect on the speed of surfing internet from real tests, but there is no much difference between ADSL2+ and ADSL when the distance is beyond 3km, which is much worse than the result of tests in lab. Performance can not be improved obviously for many long-distance users.In this situation, we need to have a deep research on the original method to find other solution. So, it is necessary and urgent to research the new solution for the long-distance users.Through the tests and analysis of line speed & noise tolerance, line attenuation and the highest Speed of up & down-load, we get the result that the issue of inlet line is the main problem of the installation and maintainance of long-distance ADSL. Especially, parallel iron core inlet line, whose user tail end is more than 80m, is the"arch criminal"of long-distance ADSL problem. So we put the entry of solving the"blind zone"of long-distance ADSL on the improvement of user's inlet cable.Getting the key result, we put the requirement on insulated resistance, electric capacity, intrusion tone, damping, free channel noise and portrait balance. And we applied the project of trial-produce of broad band peel cable by shanghai telecom to research and produce the ADSL specified skin cable with the cooperation on cable manufacturers based on the research result and relevant national standard.we have made a lot of test and research on the structure, technics, material of the product. Finally, the transmission capability and electric performance of the the ADSL specified skin cable was greatly improved. The product measured up the technique requirements we expected, and it was also standardized and solve the"blind zone"of long-distance ADSL.To testing the effect of the product, on the basis of the good effect in lab testing ,we promoted the use of the product in large-scale in shanghai telecom. With the use of 300000m ADSL specified skin cable and 5000 ADSL users ,we proved the excellent effect of cable of the long-distance ADSL. The research and the promoting of the product greatly improve the effect of the long-distance ADSL, and has good results both on economy and society.