A Cost Minimization Algorithm for a Multiuser OFDM Cognitive Radio System

Cognitive radio (CR) is a promising concept for improving the utilization of scarce radio spectrum resources. Orthogonal frequency division multiplexing (OFDM) is regarded as a technology which is well-matched for CR systems. Dynamic resource allocation is an important task in such systems. A novel resource allocation algorithm for multiuser OFDM cognitive radio system is presented in this paper. The objective is to minimize a cost function which takes into account the interference power experienced by the primary user as well as the base station transmit power for secondary users given minimum bit rate requirements for each secondary user. It is found that the proposed algorithm provides a performance which is fairly close to optimal. The influence of a relative weight parameter on the BS transmit power for secondary users and the primary user interference power is also discussed.