Abstract: A method and transmitter unit in a multi-tone, multi-line based transmission system, such as a digital subscriber line system, for determining a Power Spectral Density (PSD) of a plurality of users over a physical channel for at least one tone. Each of the users has a minimum required data rate and a maximum allowed power. A Power Minimization Problem (PMP) is formulated mathematically, introducing Lagrangian multipliers, and by utilizing a dual decomposition approach for the objective function of the PMP in order to solve the PMP on a per-tone basis.

Abstract: The present invention relates to method and arrangements for reducing crosstalk in a DSL system. This is achieved by providing the users in the network with a ghost line, i.e. a virtual line that should reflect the damage to be caused to the remaining users in the network, and that each user allocates the PSDs such that the allocated PSD is optimized against this ghost line. A central agent is adapted to continuously and individually update the ghost lines by collecting a measure indicating the impact of crosstalk from all modems.

Abstract: A qualification and monitoring function (604, 606) monitors the line conditions of a last mile access network that is connected with a multi-access broadband network. The qualification and monitoring function (604, 606) sends data to a Resource Manager (602) of the access network upon request. The monitoring function collects, stores, and analyzes performance data, media conditions and stability data using interpretation filters to derive performance indicators. The conditions of the network are also automatically provided to the resource manager (602) for immediate attention if the access network conditions exceed predetermined thresholds.

Abstract: A method and device for estimating one or more transmission properties of a telecommunication transmission line. At least one signal is sent on the line, the at least one signal including at least two frequencies for which the absolute value of the line propagation constant times the line length is less than ?, and a resulting signal is received. An estimate of at least one transmission line property is then determined by examining the relationship between the sent and resulting signal or signals. The process may be repeated, if necessary. The estimate determination may also be repeated one or more times, with each successive estimate preferably using for the determination only those frequencies for which, as previously estimated, the absolute value of the line propagation constant times the line length is less than ?.