Steffen Trautmann

A PLC broadband channel simulator for indoor communications

In this paper we propose a frequency-domain broadband channel simulator for indoor power line communications (PLC). We follow a bottom-up approach by defining the topology in a fixed mode or in a random mode. The channel matrix coefficients are derived by using the well-known two-port ABCD line modeling. The channel simulator takes into account cable characteristics, effective lengths of branches, and also loads by selecting the load impedances from a predefined set. We will show how to use our bottom-up channel simulator to generate random PLC channels and to match measurement results with a predefined approximation.

Modeling and optimization of the line-driver power consumption in xDSL systems

Optimization of the power spectrum alleviates the crosstalk noise in digital subscriber lines (DSL) and thereby reduces their power consumption at present. In order to truly assess the DSL system power consumption, this article presents realistic line driver (LD) power consumption models. These are applicable to any DSL system and extend previous models by parameterizing various circuit-level non-idealities. Based on the model of a class-AB LD we analyze the multi-user power spectrum optimization problem and propose novel algorithms for its global or approximate solution. The thereby obtained simulation results support our claim that this problem can be simplified with negligible performance loss by neglecting the LD model. This motivates the usage of established spectral optimization algorithms, which are shown to significantly reduce the LD power consumption compared to static spectrum management.

Sequential multiobjective optimization for large-scale passive filter synthesis

We propose a generic method for handling coupling among subsystems in large-scale multiobjective analog circuit synthesis. It is based on sequentially solving multiobjective optimization problems for each subsystem. The approach is exemplified on a pure feasibility problem of black-box passive filter design for a communications application. A proof-of-concept for the proposed method is provided through simulation. The practical outcome is a well-selected set of alternative design choices that all fulfill the pre-specified filter design constraints.