Interference in DFT Modulated Filter Bank Transceivers for Cognitive Radio

Abstract:
Signaling schemes in cognitive radio systems have to meet different objectives. Apart from sensing broad-band non-stationary signal spectra, dynamic spectrum access has to be implemented with affordable implementation effort. Here, discrete Fourier transform (DFT) modulated filter banks (FBs) are a suitable means to provide high time-frequency (TF) resolution for spectral estimation with the required efficient spectrum access for data transmission. However, a low implementation effort requiring pulses with small temporal support to be used in the DFT filter bank usually results in bad resolution properties in the TF domain. Furthermore, the limitation of self-interference in DFT FBs used for dynamic spectrum access has an impact on the implementation effort of the overall transceiver which simultaneously has to take into account external interference for data transmission. In this paper, we consider the design of DFT modulated FBs for the aforementioned contradicting requirements of high resolution capabilities, efficient spectrum access and implementation effort for an additive white Gaussian channel. A performance comparison is drawn for four designs which shows the simplicity of the approach and its capability to be easily extended to fading channels.