A study of channel estimation in OFDM systems

“…Hencer cannot be decoded directly and channel estimation is essential to alleviate performance degradation. Several channel estimation techniques can be employed [2]. In our purposed architecture, we employ the Least Squares (LS) algorithm.…”

Section: Adaptive Beamforming With Channel Estimationmentioning

confidence: 99%

Adaptive beamforming for OFDM based hybrid mobile satellite system

Khan¹,

Imran²,

Evans³

2009

IET Conference Publications

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Global connectivity cannot be guaranteed by terrestrial networks due to the lack of infrastructure in rural areas. Neither can satellite networks assure this due to lack of signal penetration and capacity coverage issues in densely populated areas. To bridge this gap, we propose an Orthogonal Frequency Domain (OFDM) based hybrid architecture where users are provided service by existing mobile networks in urban areas and are served by satellite in the rural areas. In such a system terrestrial and satellite networks can reuse the portion of spectrum dedicated to each of these systems resulting in significant increase in overall capacity, wider coverage and reduced cost. This frequency reuse induces severe Co-Channel Interference (CCI) at the satellite end and our work focuses on its mitigation using OFDM based adaptive beamforming.

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“…A collection of problems including channel measurements and modeling, channel estimation, and synchronization have been widely studied by researchers [5][6][7][8][9][10]. Clearly, all the performance improvement and capacity increase are based on accurate channel state information.…”

Section: Introductionmentioning

confidence: 99%

Low-complexity WLMMSE channel estimator for MB-OFDM UWB systems

Hajjaj

Chainbi

Bouallègue

2015

J Wireless Com Network

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Widely linear (WL) minimum mean square error (MMSE) channel estimation scheme have been proposed for multiband orthogonal frequency division multiplexing ultra-wideband (MB-OFDM UWB) systems dealing with non-circular signals. This WLMMSE channel estimation scheme provides significant performance gain, but it presents a high computational complexity compared with the linear one. In this paper, we derive an adaptive WLMMSE channel estimation scheme that significantly reduces the computational complexity. The complexity reduction is done in two stages. The first stage consists of a real evaluation of the WLMMSE channel estimator and the second stage follows with a reduced-rank filtering based on the singular value decomposition (SVD). Computational complexity evaluation shows that the proposed low-rank real-valued WLMMSE channel estimator has computation cost comparable with the linear MMSE. Additionally, simulations of the bit error rate (BER) performance show comparable performance with the WLMMSE channel estimator especially at high signal-to-noise ratio (SNR).

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A study of channel estimation in OFDM systems

Cited by 170 publications

References 5 publications

A Joint Timing Offset and Channel Estimation Using Fractional Fourier Transform and Cazac Sequences

A Joint Timing Offset and Channel Estimation Using Fractional Fourier Transform and Cazac Sequences

Adaptive beamforming for OFDM based hybrid mobile satellite system

Low-complexity WLMMSE channel estimator for MB-OFDM UWB systems

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