The Waterfilling Based Subcarrier and Power Allocation for OFDM Cognitive Radio Networks

Abstract

In this paper, the subcarrier and power allocation problem for the orthogonal frequency division multiplexing (OFDM) cognitive radio network which coexists with the primary network is studied. Specifically, in consideration of both transmit power constraints of secondary users and interference power constraint at each primary receiver. A cognitive waterfilling (CWF) power allocation algorithm which based upon the classical waterfilling mechanism is proposed for the single SU and multi-PU scenario. As for the multi-SU and multi-PU case, we present an efficient joint subcarrier and power allocation algorithm called MS-CWF algorithm with low complexity. Simulation results show the effectiveness of the proposed CWF and MS-CWF algorithms.