This book investigates the physical layer aspects of high-speed transmission on twisted-pair
copper wires where the most performance-critical components are multi-input multi-output
(MIMO) precoding and multi-line spectrum optimization as well as optimized scheduling of the
transmission time slots on the fiber to the distribution point (FTTdp) copper link. The book
brings theoretical results into the implementation which requires the introduction of
realistic channel models and more practical implementation constraints as found in the copper
access network. A good understanding of the transmission medium twisted-pair telephone cable
bundles is the basis for this work. Starting from the analysis of measurement data from
twisted-pair cable bundles at high frequencies it presents a MIMO channel model for the FTTdp
network which allows the characteristic effects of high-frequency transmission on copper cable
bundles in simulation to be reproduced and the physical layer transmission methods on the
copper channels to be analyzed and optimize. The book also presents precoding optimization for
more general power constraints and implementation constraints. The maximization of data rate in
a transmission system such as G.fast or VDSL is a combinatorial problem as the rate is a
discrete function of the number of modulated bits. Applying convex optimization methods to the
problem offers an efficient and effective solution approach that is proven to operate close to
the capacity of the FTTdp channel. In addition to higher data rates low power consumption is
another important aspect of the FTTdp network as it requires many access nodes that are
supplied with power from the subscriber side over the twisted- pair copper wires. Discontinuous
operation is a method of quickly adding and removing lines from the precoding group. To
implement this the system switches between different link configurations over time at a high
frequency. The transmission times of all lines are jointly optimized with respect to the
current rate requirements. Discontinuous operation is used to save power but also makes it
possible to further increase the data rates taking the current subscriber traffic requirements
into account. These methods are compared with theoretical upper bounds using realistic channel
models and conditions of a system implementation. The performance analysis provides deeper
insights into implementation complexity trade-offs and the resulting gap to channel capacity.
