A Modified Low Complexity Mask Compliant Spectral Precoder for OFDM Based Cognitive Radio

摘要

Orthogonal frequency division multiplexing (OFDM) is a promising approach used in Cognitive radio (CR) systems. However, due to side lobe leakage in OFDM systems interference caused to the primary users that minimize the quality-of- service (QoS). In order to improve QoS of the primary user we have to keep interference level in the primary user band below the specified mask. The available techniques are either computationally complex or spectrally not efficient. This paper proposes a spectral precoder which is computationally simple and spectrally efficient that reduces Error Vector Magnitude (EVM) of secondary user and restricts the transmitted wave form below the prescribed mask. Simulation results display that the proposed method overcomes existing methods in terms of EVM, BER and complexity.