RESEARCH OF INTERFERENCE NOISE IN VDSL2 SYSTEMS WHEN OPERATING OVER TPP TYPE TELEPHONE CABLES

Abstract

The article presents the results of the research of the interference noise in transmission systems using the VDSL2 technology when working over TPP type telephone cables. The research was carried out by analyzing the modeling of VDSL2-systems with the frequency plan B8-6 [998-M2x-B] over TPP-0.4 type telephone cable using traditional orthogonal harmonic signals (OHS) and generalized class orthogonal harmonic signals (GC OHS). Interference noise for both downstream and upstream transmission directions was researched. Interference noise was estimated in relative values as a percentage ratio of the interference noise and signal effective values. The article presents three-dimensional diagrams of the dependence of the interference noise values distribution in channels from the integration beginning (start) moment when the line length varies from 200 to 500 meters. It was determined that interference noise is unevenly distributed in the VDSL2-system channels and their value significantly depends on the integration start sample number. The optimal values of the integration start are calculated by the criterion of the minimum of the arithmetic mean for all information channels of the interference noise value. The dependences of the interference noise distribution in the VDSL2-system channels are investigated when using traditional OHS and GC OHS with the optimal values of the integration start. The dependence of the interference noise in the VDSL2-system channels is analyzed depending on the line length, the type of the orthogonal harmonic signals and the transmission direction. The efficiency of the generalized class orthogonal harmonic signals application in comparison with traditional OHS application is proved. The significant influence of the quantity of adjacent channels on the interference noise value is determined.