A Low-Complexity Channel Estimation for OFDM Systems Based on CIR Length Adaptation

Park, Hyung-Rae

doi:10.1109/access.2022.3198962

Cited by 8 publications

(28 citation statements)

References 35 publications

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“…If the NLoS scenarios are detected, an optimized threshold based on the constant false alarm rate (CFAR) is constructed. According to [20], the CFAR-based threshold (CFAR-Thr), denoted by T h , is derived as [21] T h = −2 σ 2 ln P f ,…”

Section: B Los-aided Detection Threshold For Resolvable Pathsmentioning

confidence: 99%

Enhanced ELM Based Channel Estimation for RIS-Assisted OFDM Systems With Insufficient CP and Imperfect Hardware

et al. 2022

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In unmanned aerial vehicle (UAV)-assisted orthogonal frequency division multiplexing (OFDM) systems, the potential advantage of the line-of-sight (LoS) path, characterized by its high probability of existence, has not been fully harnessed, thereby impeding the improvement of channel estimation (CE) accuracy. Inspired by the ideas of integrated sensing and communication (ISAC), this letter develops a LoS sensing method aimed at detecting the presence of LoS path. Leveraging the prior information obtained from LoS path detection, the detection thresholds for resolvable paths are proposed for LoS and Non-LoS (NLoS) scenarios, respectively. By employing these specifically designed detection thresholds, denoising processing is applied to classical least square (LS) CE, thereby improving the CE accuracy. Simulation results validate the effectiveness of the proposed method in enhancing CE accuracy and demonstrate its robustness against parameter variations.

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Section: B Los-aided Detection Threshold For Resolvable Pathsmentioning

confidence: 99%

Enhanced ELM Based Channel Estimation for RIS-Assisted OFDM Systems With Insufficient CP and Imperfect Hardware

et al. 2022

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“…The work in [5] addressed the noise power calculation using repeated nulled subcarriers. An adaptive minimum mean square error (MMSE)-CE was addressed in [6] related with maximum access delay time estimation.…”

Section: Introductionmentioning

confidence: 99%

“…For OFDM systems, several noise variance or SNR estimation schemes have been studied [1][2][3][4][5][6][7][8][9][10][11]. There are two kinds of estimation schemes: one is data-aided (DA) scheme requiring pilot symbols and the other is non-data aided (NDA) scheme using the cyclic redundancy induced by the cyclic prefix (CP).…”

Section: Introductionmentioning

confidence: 99%

“…In this estimation scheme, reference signals suitable for frequency selective fading were designed and utilized, and the noise variance was most accurately estimated. Although there has been continuous improvement in estimation performance in the studies disclosed in [2] [6][7][8][9], these studies have not yet proposed an estimator considering the PDP. Estimation of the PDP is essential for the MMSE-CE of the OFDM system.…”

Section: Introductionmentioning

confidence: 99%

“…If the PDP is first estimated and used, performance approaching the MMSE can be expected in estimating the noise variance. The conventional works in [6], [10], and [11] presented the PDP or MMSE-CE methods based on pilot symbols. In [12], the authors presented the CE scheme in IEEE 802.11p/WAVE system under the assumption that the maximum access delay time is known to the receiver.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Improved Maximum Access Delay Time, Noise Variance, and Power Delay Profile Estimations for OFDM Systems

2022

KSII TIIS

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In this paper, we propose improved maximum access delay time, noise variance, and power delay profile (PDP) estimation schemes for orthogonal frequency division multiplexing (OFDM) system in multipath fading channels. To this end, we adopt the approximate maximum likelihood (ML) estimation strategy. For the first step, the log-likelihood function (LLF) of the received OFDM symbols is derived by utilizing only the cyclic redundancy induced by cyclic prefix (CP) without additional information. Then, the set of the initial path powers is sub-optimally obtained to maximize the derived LLF. In the second step, we can select a subset of the initial path power set, i.e. the maximum access delay time, so as to maximize the modified LLF. Through numerical simulations, the benefit of the proposed method is verified by comparison with the existing methods in terms of normalized mean square error, erroneous detection, and good detection probabilities.

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Joint Identification for Number of Transmit Antennas and Channel Order

Wang,

He,

Wang

2023

IEEE Access

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Identifying the number of transmit antennas and the channel order is an important step in recovering the original information for a non-cooperative communication system. Traditional methods overestimate the number of transmit antennas and the channel order due to the coupling effect. This paper proposes a novel joint identification scheme to determine the number of transmit antennas and the channel order, which consists of two stages. Specifically, in the first stage, an improved weighted Gerschgorin disk identifier is developed to obtain the number of transmit antennas using frequency domain signals. In the second stage, we first derive an equivalent time-domain model to improve the utilization of the receiver antenna, and then a novel test statistic following F distribution is constructed to perform the sequential binary hypothesis testing. Finally, the channel order is obtained using the estimated number of transmit antennas in the first stage. The simulation results show that the proposed joint identification scheme significantly outperforms the existing approaches.

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A Low-Complexity Channel Estimation for OFDM Systems Based on CIR Length Adaptation

Cited by 8 publications

References 35 publications

Enhanced ELM Based Channel Estimation for RIS-Assisted OFDM Systems With Insufficient CP and Imperfect Hardware

Enhanced ELM Based Channel Estimation for RIS-Assisted OFDM Systems With Insufficient CP and Imperfect Hardware

Improved Maximum Access Delay Time, Noise Variance, and Power Delay Profile Estimations for OFDM Systems

Joint Identification for Number of Transmit Antennas and Channel Order

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