Turbo Coded Single Sideband OFDM-OQAM Signaling through Frequency Selective Rayleigh Fading Channels

TL;DR

This paper evaluates the BER performance of turbo coded OFDM-OQAM signals with SSB-like modulation over Rayleigh fading channels, employing RRC pulses, and introduces algorithms for CFO, channel, and noise estimation.

Contribution

It presents a novel system combining turbo coding, OFDM-OQAM, and SSB-like modulation with new algorithms for synchronization and channel estimation in Rayleigh fading environments.

Findings

Turbo coded OFDM-OQAM outperforms uncoded systems in BER.

Use of RRC pulse and Hilbert transform enhances signal robustness.

New algorithms effectively estimate CFO, channel, and noise variance.

Abstract

This work investigates the bit-error-rate (BER) performance of turbo coded orthogonal frequency division multiplexed - offset quadrature amplitude modulated (OFDM- OQAM) signals transmitted through frequency selective Rayleigh fading channels in the presence of carrier frequency offset (CFO) and additive white Gaussian noise (AWGN). The highlight of this work is to use the root raised cosine (RRC) pulse and its Hilbert transform as the complex-valued transmit filter and a simple matched filter at the receiver. The proposed system is similar to single sideband (SSB) modulation, that has roots in analog communications. Turbo code and subcarrier diversity is employed to improve the BER performance over that of an uncoded system. Discrete-time algorithms for frame detection, two-step CFO, channel and noise variance estimation have been proposed. A single transmit and receive antenna is assumed. Similar work has not been done earlier.