A Subspace-Based Frequency Synchronization Algorithm for Multicarrier Communication Systems

We present a subspace-based polynomial rooting algorithm to estimate the frequency bias (FB) of generalized frequency division multiplexing (GFDM) systems employing null subcarriers and repetitive sub-symbols. The estimation process is classified into fractional FB (FFB) and integer FB (IFB) estimat...

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Bibliographic Details
Published inMathematics (Basel) Vol. 12; no. 16; p. 2568
Main Authors Yung-Yi, Wang, Shih-Jen, Yang
Format Journal Article
LanguageEnglish
Published Basel MDPI AG 01.08.2024
Subjects
Accuracy
Algorithms
Bandwidths
Communications systems
Computer simulation
Efficiency
Estimation
Frequency division multiplexing
Frequency synchronization
Maximum likelihood estimates
multicarrier modulations
Periodic structures
polynomial rooting
Polynomials
Radio networks
Real time
root-MUSIC algorithm
Satellite communications
Signal strength
Spectrum allocation
Subcarriers
subspace-based algorithm
Subspaces
Symbols
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Summary:We present a subspace-based polynomial rooting algorithm to estimate the frequency bias (FB) of generalized frequency division multiplexing (GFDM) systems employing null subcarriers and repetitive sub-symbols. The estimation process is classified into fractional FB (FFB) and integer FB (IFB) estimation. The use of repetitive sub-symbols creates a quasi-periodic structure in the FB-distorted received signal, allowing the proposed algorithm to estimate the FFB using the root-MUSIC algorithm. Based on this, the proposed algorithm compensates for the FFB in the received signal and then estimates the null subcarrier pattern (NSP) in the frequency domain. As a result, the IFB estimate can be obtained in a maximum likelihood (ML) manner. Before the NSP estimation, this study uses a sub-symbol combiner to enhance signal strength of the FFB-aligned signal, ensuring the reliability of the IFB estimate. Computer simulations show that the proposed subspace-based algorithm has several advantages over traditional FB estimation methods: 1. Unlike some existing algorithms that use a training sequence to estimate FB, the proposed approach is a semi-blind algorithm because it can deliver information through repeated sub-symbols while estimating FB; 2. The proposed algorithm demonstrates excellent estimation accuracy compared to most traditional FB estimation algorithms; and 3. The proposed algorithm is computationally efficient, making it applicable to real-time applications in future communication systems.
ISSN:2227-7390
DOI:10.3390/math12162568