An efficient Lagrange Multiplier search algorithm for Optimal Spectrum Balancing in crosstalk dominated xDSL systems
Venue
Proceeding IEEE ICASSP, IEEE (2006), pp. 101-104
Publication Year
2006
Authors
Paschalis Tsiaflakis, Jan Vangorp, Marc Moonen, Jan Verlinden, Katleen Van Acker, Raphael Cendrillon
BibTeX
Abstract
In modern DSL systems, multi-user crosstalk is the major source of performance
degradation. Optimal Spectrum Balancing (OSB) is a centralized algorithm that
optimally allocates the available transmit power over frequencies, thereby
mitigating the e?ect of crosstalk. OSB uses Lagrange multipliers to enforce
constraints that are coupled over frequencies. However, ?nding the optimal Lagrange
multipliers can become complex when more than two users are considered. Starting
from the single user case, this paper presents a number of properties, which are
then extended to the multi-user case and lead to an e?cient search algorithm for
the Lagrange multipliers. Simulations show that the number of Lagrange multiplier
evaluations is as small as 40, independent of the number of users, which is much
faster than currently known search algorithms.
