Equalization of Time-Varying Channels

Schniter, Philip; Hwang, Sung-Jun; Das, Sibasish; Kannu, Arun Pachai

doi:10.1016/b978-0-12-374483-8.00006-6

Cited by 13 publications

(7 citation statements)

References 131 publications

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“…From this we conclude that τ (ξ + j a , x + Finally, we investigate an important assumption made in wireless communications. To facilitate the inversion of the channel matrix in (1), it is commonly assumed that the channel matrix is a diagonal matrix [8,9,27,38]. Clearly, if the Gabor system G(g, Λ) is a (Riesz) basis for L 2 (R d ), then there is a bijection between operators and channel matrices, and thus there exist diagonal channel matrices.…”

Section: Uniqueness Resultsmentioning

confidence: 99%

Uniqueness and reconstruction theorems for pseudodifferential operators with a bandlimited Kohn-Nirenberg symbol

Gröchenig

Pauwels

2013

Adv Comput Math

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Motivated by the problem of channel estimation in wireless communications, we derive a reconstruction formula for pseudodifferential operators with a bandlimited symbol. This reconstruction formula uses the diagonal entries of the matrix of the pseudodifferential operator with respect to a Gabor system. In addition, we prove several other uniqueness theorems that shed light on the relation between a pseudodifferential operator and its matrix with respect to a Gabor system.

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Section: Uniqueness Resultsmentioning

confidence: 99%

Uniqueness and reconstruction theorems for pseudodifferential operators with a bandlimited Kohn-Nirenberg symbol

Gröchenig

Pauwels

2013

Adv Comput Math

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“…And the data is modulated with QPSK of unit power. The maximal normalized Doppler shifts 1 for the first and third hop are set as 0.05 while that of the second hop is set as 0.15. Two relaying paths are considered (K= 2).…”

Section: Simulation Results and Discussionmentioning

confidence: 99%

“…One way to handle it is to iterate between data detection and channel estimation, e.g., through expectation-maximization (EM) algorithm [1], assuming knowledge of channel statistics and noise variance. When the noise variance is unknown, a solution based on variational inference was proposed in [2].…”

Section: Introductionmentioning

confidence: 99%

Equalizing multihop OFDM relay channel under unknown channel orders and Doppler frequencies

Zhou¹,

Min²,

Qin

et al. 2014

2014 IEEE International Conference on Communications (ICC)

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Abstract-In this paper, equalization of multihop relaying orthogonal frequency division multiplexing (OFDM) signal is investigated under time-varying channel with unknown noise powers, channel orders and Doppler frequencies. An iterative algorithm is developed under variational expectation maximization (EM) framework. The proposed algorithm iteratively estimates the channel, learns the channel and noise statistical information, and recovers the unknown data, using only limited number of pilot subcarrier in one OFDM symbol. Simulation results show that, without any statistical information, the performance of the proposed algorithm is very close to that of the optimal channel estimation and data detection algorithm, which requires specific information on system structure, channel tap positions, channel lengths, Doppler shifts as well as noise powers.

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“…Since doubly selective or time-varying multipath channels caused by the propagation channel environment of IIoT will affect the robustness of the entire communication system [20]. In addition, since the channel state is varying and the equalizer must be constantly updated to match the channel changing, it is difficult to realize estimation and equalization simultaneously [28,29]. A low-complexity channel estimation scheme based on compressed sensing in IIoT environment is proposed in [20], and the simulations results show that the proposed method can effectively improve the robustness of the system.…”

Section: The Robust Communications In Iiotmentioning

confidence: 99%

EKF/UKF-based channel estimation for robust and reliable communications in V2V and IIoT

Yong

Shen

Sun

et al. 2019

J Wireless Com Network

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Cyber-physical systems (CPSs) are characterized by integrating computation, communication, and physical system. In typical CPS application scenarios, vehicle-to-vehicle (V2V) and Industry Internet of Things (IIoT), due to doubly selective fading and non-stationary channel characteristics, the robust and reliable end-to-end communication is extremely important. Channel estimation is a major signal processing technology to ensure robust and reliable communication. However, the existing channel estimation methods for V2V and IIoT cannot effectively reduce intercarrier interference (ICI) and lower the computation complexity, thus leading to poor robustness. Aiming at this challenge, according to the channel characteristics of V2V and IIoT, we design two channel estimation methods based on the Bayesian filter to promote the robustness and reliability of end-to-end communication. For the channels with doubly selective fading and non-stationary characteristics of V2V and IIoT scenarios, in the one hand, basis extended model (BEM) is used to further reduce the complexity of the channel estimation algorithm under the premise that ICI can be eliminated in the channel estimation. On the other hand, aiming at the non-stationary channel, a channel estimation and interpolation method based on extended Kalman filter (EKF) and unscented Kalman filter (UKF) Bayesian filters to jointly estimate the channel impulse response (CIR) and time-varying time domain autocorrelation coefficient is adopted. Through the MATLAB simulation, the robustness and reliability of end-to-end communication for V2V and IIoT are promoted by the proposed algorithms.

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Equalization of Time-Varying Channels

Cited by 13 publications

References 131 publications

Uniqueness and reconstruction theorems for pseudodifferential operators with a bandlimited Kohn-Nirenberg symbol

Uniqueness and reconstruction theorems for pseudodifferential operators with a bandlimited Kohn-Nirenberg symbol

Equalizing multihop OFDM relay channel under unknown channel orders and Doppler frequencies

EKF/UKF-based channel estimation for robust and reliable communications in V2V and IIoT

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