The constrained normalized-rate iterative algorithm

Dynamic spectrum management (DSM) aims to increase the utilization of cable capacity by adapting the spectra of digital subscriber line (DSL) systems to the real network environment. In this paper we present a new DSM algorithm: the constrained normalized-rate iterative algorithm (C-NRIA). The C-NRIA extends the existing NRIA by ensuring predefined fixed bitrates to some of the users in the cable bundle while offering bitrates to the remaining users on a best effort basis. This reflects many business scenarios where a number of users must be guaranteed a specific service. We show that this type of the optimization problem can be solved efficiently with the C-NRIA by introducing only one balancing parameter that splits the cable capacity among the two user groups.