Spread Spectrum Symbol Detection With Blind Interference Suppression in FBMC-SS

Abstract

Recent works have demonstrated Filter Bank Multicarrier Spread Spectrum (FBMC-SS) to be a robust communication scheme in the presence of high-power interferers. Existing FBMC-SS symbol detector designs based on analysis filter banks (AFB) suggest using an optimal combining scheme to suppress the interferers, necessitating some noise/interference power estimation method. In this paper, we introduce a symbol detector with blind interference suppression by extending a recently developed packet detection method. We then provide an analysis to show that the existing AFB-based symbol detector and the one proposed in this paper are equivalent in typical usage scenarios. A fully-fledged receiver design is proposed utilizing this symbol detector, with specifics presented for estimation of the channel impulse response and carrier frequency offset (CFO). We also outline a method of iterating upon the channel and CFO estimations to improve the quality of both parameters. Moreover, a modification to allow improved performance of the symbol detector at high SNR is provided. Finally, simulated performance results are presented to corroborate these findings and demonstrate the efficiency of this receiver design.

Multicode Signaling in a Filter Bank Multicarrier Spread Spectrum System and Its Application to HF Communications

“…This new implementation that has been named the NMF-based receiver is different from the conventional receivers in previous works [6], [7] that were based on an analysis filter bank (AFB). The results presented in [19] show that the NMF-based receiver, when compared to its AFB counterpart, leads to a reduced complexity and for certain channel conditions may have a superior performance.…”

“…The proposed detector that has been named normalized matched filter (NMF) was first presented in [18]. More detailed study of the NMF and its adoption for development of a full receiver structure has been recently presented in [19]. This new implementation that has been named the NMF-based receiver is different from the conventional receivers in previous works [6], [7] that were based on an analysis filter bank (AFB).…”

“…The multicodes that have been introduced in this work are chosen such that the low PAPR of the original design of FBMC-SS, [13], is preserved. It should be also noted that the particular form of FBMC that has been mostly adopted by us [6], [7], [18], [19], and others [14]- [17], makes use of subcarrier bands that are non-overlapping. This implementation of FBMC is often referred to as filtered multi-tone (FMT), in the broader class of filter bank communications; e.g., see [21].…”

“…The goal of this paper is to further explore the multicode method of [20] and develop details of the respective receiver structures, following the conventional AFB-based receiver of [6], [7] and the NMF-based receiver that has been recently developed in [19]. More particularly, this paper makes the following contributions:…”

“…We use x(t) when reference is made to a continuous-time signal, and x[n] when referring to a discrete-time signal. The signal samples are obtained by making use of a proper synchronization technique, such as the one discussed in [19]. Continuous-time formulations are adopted for presentation of the fundamental concepts and theoretical analysis in Sections II and the beginning of Section III.…”