Optimal position of external node for very-high-bitrate digital subscriber line

This paper describes a specific variant of very-high-speed digital subscriber line (VDSL) for access network in the Czech Republic under the terms of frequency bands released by Telefonica O₂ CR. The spectral profiles are characterized by alternating bands for upstream and downstream directions when using frequency duplex. Further discussion deals with achievable bitrates under different conditions and the expected profiles that should be offered to subscribers. The resulting bitrates are calculated with respect to the length of the line with a copper core diameter of 0.4 mm and the number of disturbance sources for upstream and downstream directions. The analysis was performed using real distribution of subscriber line lengths in the Czech Republic. Higher penetration can be achieved with optical-metallic hybrid network. The optimal position of external node for very-high-speed digital subscriber line is deduced and proposed.