I. Introduction
Optimization of the transmit spectra among multiple users reduces interference in modern communication systems. With a limited bandwidth and an increasing number of users, the achievable data rates in various wireless and wireline networks are limited by the interference between users. In a DSL network, the crosstalk between the copper lines becomes a severe limitation to the data rate when the distance between the interfering transmitter and the victim receiver is small. An excellent management of the crosstalk between the various users sharing a DSL binder is critical in further increasing data rate and reducing power consumption in DSL networks. Dynamic Spectrum Management provides a framework for such management; specifically, level-2 DSM methods, often referred to as spectrum balancing algorithms, optimize the users' spectra by reducing the crosstalk between users [1].