Design of prototype filters for perfect reconstruction DFT filter bank transceivers

Abstract

In recent years, multicarrier modulation techniques have stirred great interest among researchers. One specific form of multicarrier modulation, referred to as orthogonal frequency division multiplexing (OFDM), has been deployed in many applications. Despite their huge popularity, OFDM systems have a few, but important, drawbacks. In particular, OFDM relies on the inverse fast Fourier transform (FFT) for modulation purposes, which leads to a poor spectral containment and, consequently, to a high susceptibility to narrowband noise. To mitigate this problem, we propose to employ over-interpolated perfect reconstruction (PR) discrete Fourier transform (DFT) filter banks. The design of such filter banks is addressed using a novel method that guarantees the PR property to be satisfied while the spectral containment is being maximized. The equalization of frequency-selective channels exploits the fact that the filter banks do not contribute to any distortion due to its PR nature. A simple scheme, taking the form of an one-tap per subcarrier equalizer, is considered. Experimental results indicate that the spectral containment of the proposed PR DFT filter bank transceiver is indeed superior to the OFDM system. Moreover, simulations conducted in a digital subscriber line (DSL)-like environment contaminated by a narrowband noise show that the achievable bit rate of the proposed transceiver is significantly higher than that of a conventional OFDM system.