Optimal dynamic spectrum management algorithms for multi-user full-duplex DSL networks

Driven by the exceedingly high data rates achieved in single user implementations, interest in multi-user (MU) full-duplex (FDX) transmission for digital subscriber line (DSL) networks is surging. As near end crosstalk is no longer avoided in such networks, one should resort to dynamic spectrum management (DSM) techniques to deal with it. Care is to be taken when choosing the employed DSM operating point, as this choice directly determines the achieved performance. This paper therefore proposes three novel DSM algorithms for the MU FDX DSL network. First, an optimal spectrum balancing (OSB) algorithm is derived which calculates the globally optimal DSM operating point, but does so at an exceedingly high computational cost. Two low-complexity distributed spectrum balancing (DSB) algorithms are then proposed, for which simulations show that their performance is very close to what is achieved by the OSB algorithm. Therefore, these DSB algorithms can be used to estimate the achievable performance of an MU FDX DSL network. Such performance estimations have shown that FDX transmission will lead to significant gains in multi-user DSL networks as well.