Performance Evaluation of Zero-Forcing Equalization for F-OFDM Signals in The Presence of Phase Noise and Fading

Abstract

In this thesis report, we present the performance evaluation of a low-complexity fast – orthogonal–frequency–division–multiplexing (F–OFDM) scheme, in the presence of phase-noise (PHN), working under the generic linear fading channels (like two-wave-with-diffuse-power (TWDP) multipath fading and modal dispersion in multi-mode-fiber optic channel). Here, a single-tap zero-forcing (ZF) equalizer is utilized to compensate the channel-impulse-response (CIR) without sacrificing data-rate, in which the discrete-cosine-transform (DCT) operation is replaced by the discrete-Fourier-transform (DFT) operation at the receiver. The phase noise variations are modeled by utilizing the random–walk paradigm, in which PHN is dependent on the model parameters/statistics. Therefore, main focus is on the impact of PHN on the performance of single-tap ZF equalization for F–OFDM signals. Simulation results are presented to illustrate efficiency and efficacy of underlying F–OFDM system, while working under TWDP, Rician and Rayleigh multipath fading linear channels. It can be inferred from results that the PHN severely affects/deteriorates the performance of F–OFDM based communication systems in terms of high bit-error-rate (BER), when the PHN variations are large. Further, a typical case of TWDP fading (where both the specular components are in opposite phase) is also investigated under similar fading conditions in the absence as well as in the presence of PHN. Moreover, the TWDP fading model is found to be quite appropriate for analyzing/investigating the BER performance of communication systems using the binary-phase-shift-keying modulation technique. The presented research work is not only finding applications in advanced wireless communication systems, but also appearing to be appropriate choice for optical fiber communication. Future work includes the usage of discrete-sine-transform (DST) for multicarrier communication.