An Enhanced DFT-Based Channel Estimation Using Virtual Interpolation with Guard Bands Prediction for OFDM

Seo, Jong-Soo; Wee, Jung-Wook; Jeon, Won-Gi; Paik, Jong-Ho; Kim, Dongku

doi:10.1109/pimrc.2006.254263

Cited by 18 publications

(8 citation statements)

References 7 publications

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“…With this in mind, we propose a low-complexity method that can shift the distortion at the edge in the active band by adding virtual sub-carriers to outside of the active band. In other studies, virtual sub-carrier insertion methods have been proposed [5,6]. However our proposal is new in considering the property of received signals that are multiplexed by CI, and furthermore, our proposal is far more effective than others in reducing the complexity of the circuits.…”

Section: Virtual Sub-carrier Allocation Methodsmentioning

confidence: 92%

“…It is impossible to separate the impulse responses perfectly under real conditions. They result in the channel estimation accuracy deteriorating, especially sub-carriers at the edge in the active band [5,6]. In this paper, we show how the degradation of the channel estimation accuracy is concentrated to the sub-channel at the edge by CIM/DFT-CE in the MIMO-OFDMA system under real conditions.…”

Section: Introductionmentioning

confidence: 84%

“…where we ignore the AWGN component in (6). Subsequently, we can express the received signal at the odd sub-carriers as:…”

Section: Virtual Sub-carrier Allocation Methodsmentioning

confidence: 99%

See 2 more Smart Citations

New Virtual Sub-Carrier Allocation Method for CI Multiplexed Channel Estimation Signals on MIMO-OFDMA

Hideo

Shimpei

Yasuhiro

et al. 2007

2007 IEEE 18th International Symposium on Personal, Indoor and Mobile Radio Communications

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In a MIMO-OFDMA system, carrier interferometry multiplexed (CIM) signals with the discrete Fourier transform based channel estimation (CIM/DFT-CE) have been proposed. Using CIM/DFT-CE, high channel estimation accuracy is realized with a small number of symbols under ideal conditions. In this paper we indicate that the channel estimation accuracy of the sub-channel at the edge in the active band is significantly degraded under real conditions. To improve this degradation, we propose a new virtual sub-carrier allocation method, taking the periodic property of the CIM signals in the receiver into consideration. We use computer simulation to demonstrate that the channel estimation accuracy of the sub-channel at the edge is improved by the proposed method under real conditions.

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Section: Virtual Sub-carrier Allocation Methodsmentioning

confidence: 92%

Section: Introductionmentioning

confidence: 84%

See 1 more Smart Citation

New Virtual Sub-Carrier Allocation Method for CI Multiplexed Channel Estimation Signals on MIMO-OFDMA

Hideo

Shimpei

Yasuhiro

et al. 2007

2007 IEEE 18th International Symposium on Personal, Indoor and Mobile Radio Communications

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“…In [18], an estimate of noise variance from reference signals on multiple OFDM symbols was used to clean the reference signal in the time domain before applying interpolation. A new DFT improvement algorithm based channel estimation was proposed in [19] using guard band prediction with virtual LMMSE interpolation in order to reduce the edge effect and to overcome the problem of pilot mismatching. The traditional DFT method was improved by about 2 dB gain in SNR at a BER of 10 −2 where it tested in a multipath environment with 100 Hz Doppler frequency.…”

Section: Literature Reviewmentioning

confidence: 99%

Sparse DFT Based Channel Estimation In OFDM Systems

Abboud¹,

Sabbar²

2020

Iraqi Journal of ICT

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Channel estimation is an essential part of Orthogonal Frequency Division Multiplexing (OFDM) communication systems. In this paper, two Discrete Fourier Transform (DFT) improvement algorithms are proposed and compared where the 1st one exploits channel sparsity concept while the other considers significant channel coefficients only. In the proposed algorithms; Enhanced and Sparse DFT (E-DFT and S-DFT), different number of significant channel components is selected either by a threshold determining procedure such as in E-DFT, or through determining channel sparsity level such as in S-DFT. In the presence of Doppler frequency shifts, the Inter Symbol Interference (ISI) effect on channel coefficients is successfully reduced using the proposed estimation algorithms. Vehicular A-ITU channel model is considered with a relatively high vehicle speed up to 68 Km/h in order to test the suitability of the proposed algorithms for mobile systems. E-DFT and S-DFT improves conventional as well as previous DFT improvement methods (I-DFT) suggested by [7], [8], [9], [15]. For 64 subcarriers, S-DFT outperforms E-DFT and I-DFT by about 3dB at a BER of 0.01 with a mobility reaches 45 Km/h, and by about 0.4dB and 2.5dB at a BER of 0.02 with a mobility reaches 68Km/h.

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“…It is based on frequency domain CSI interpolation schemes using sparsely arranged training subcarriers, on which power density is concentrated. Although numerous interpolation schemes have been investigated [ 20 , 21 ], our proposal only extracts phase components with simple linear least squares regression, by using quite limited number of subcarriers. Furthermore, training subcarriers are dispersed on plural antenna elements to further reduce peak-to-average power ratio (PAPR) per antenna element.…”

Section: Introductionmentioning

confidence: 99%

First Eigenmode Transmission by High Efficient CSI Estimation for Multiuser Massive MIMO Using Millimeter Wave Bands

Maruta

Iwakuni

Ohta

et al. 2016

Sensors

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Drastic improvements in transmission rate and system capacity are required towards 5th generation mobile communications (5G). One promising approach, utilizing the millimeter wave band for its rich spectrum resources, suffers area coverage shortfalls due to its large propagation loss. Fortunately, massive multiple-input multiple-output (MIMO) can offset this shortfall as well as offer high order spatial multiplexing gain. Multiuser MIMO is also effective in further enhancing system capacity by multiplexing spatially de-correlated users. However, the transmission performance of multiuser MIMO is strongly degraded by channel time variation, which causes inter-user interference since null steering must be performed at the transmitter. This paper first addresses the effectiveness of multiuser massive MIMO transmission that exploits the first eigenmode for each user. In Line-of-Sight (LoS) dominant channel environments, the first eigenmode is chiefly formed by the LoS component, which is highly correlated with user movement. Therefore, the first eigenmode provided by a large antenna array can improve the robustness against the channel time variation. In addition, we propose a simplified beamforming scheme based on high efficient channel state information (CSI) estimation that extracts the LoS component. We also show that this approximate beamforming can achieve throughput performance comparable to that of the rigorous first eigenmode transmission. Our proposed multiuser massive MIMO scheme can open the door for practical millimeter wave communication with enhanced system capacity.

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An Enhanced DFT-Based Channel Estimation Using Virtual Interpolation with Guard Bands Prediction for OFDM

Cited by 18 publications

References 7 publications

New Virtual Sub-Carrier Allocation Method for CI Multiplexed Channel Estimation Signals on MIMO-OFDMA

New Virtual Sub-Carrier Allocation Method for CI Multiplexed Channel Estimation Signals on MIMO-OFDMA

Sparse DFT Based Channel Estimation In OFDM Systems

First Eigenmode Transmission by High Efficient CSI Estimation for Multiuser Massive MIMO Using Millimeter Wave Bands

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