Channel Estimation and Pilot Design for Uplink Sparse Code Multiple Access System Based on Complex-Valued Sparse Autoencoder

Channel estimation is one of the most important aspects of wireless communication. Especially, in sparse code multiple access (SCMA) system, the accuracy of channel estimation has a significant impact on decoding performance. Various methods, so far, have been developed for channel estimation. Most...

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Main Authors: Quan Yuan, Dezhi Li, Zhenyong Wang, Chang Liu, Ci He
Format: Article
Language:English
Published: IEEE 2025-01-01
Series:IEEE Access
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Online Access:https://ieeexplore.ieee.org/document/8667100/
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author Quan Yuan
Dezhi Li
Zhenyong Wang
Chang Liu
Ci He
author_facet Quan Yuan
Dezhi Li
Zhenyong Wang
Chang Liu
Ci He
author_sort Quan Yuan
collection DOAJ
description Channel estimation is one of the most important aspects of wireless communication. Especially, in sparse code multiple access (SCMA) system, the accuracy of channel estimation has a significant impact on decoding performance. Various methods, so far, have been developed for channel estimation. Most of these methods regard channel estimation as a parameter estimation problem of linear models. However, these methods require lots of time–frequency resources to ensure high estimation accuracy. In massive connection scenarios, high pilot overhead makes the spectrum resource more scarce. Therefore, the drawback of conventional channel estimation methods limits the further improvement of system capacity in the Internet of Things (IoT) when time–frequency resources are restricted. To address this problem, in this paper, we propose an efficient channel estimation scheme and sparse pilot structure design method in an SCMA system based on complex-valued sparse autoencoder which is effective to learn features of the wireless channel. Complex-valued sparse autoencoder is a kind of neural network with complex-valued weights. It contains two parts: encoder and decoder. In this paper, the encoder part is used to realize the pilot design. Channel estimation is implemented by the decoder. Complex-valued weights obtained from training are used as baseband pilots. Compared with maximum likelihood channel estimation (MLE) of the linear model, the proposed method can achieve higher channel estimation accuracy with more sparse pilot structure. The bit-error rates’ performance of the SCMA receiver in this paper is very close to that of the perfect channel state information (CSI).
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spelling doaj-art-fbe5140ccf6b4575b898c315f16c8e7b2025-07-24T23:01:04ZengIEEEIEEE Access2169-35362025-01-011312355912356910.1109/ACCESS.2019.29049908667100Channel Estimation and Pilot Design for Uplink Sparse Code Multiple Access System Based on Complex-Valued Sparse AutoencoderQuan Yuan0https://orcid.org/0000-0003-2152-4375Dezhi Li1Zhenyong Wang2https://orcid.org/0000-0001-8236-7073Chang Liu3Ci He4School of Electronics and Information Engineering, Harbin Institute of Technology, Harbin, ChinaSchool of Electronics and Information Engineering, Harbin Institute of Technology, Harbin, ChinaSchool of Electronics and Information Engineering, Harbin Institute of Technology, Harbin, ChinaSchool of Electronics and Information Engineering, Harbin Institute of Technology, Harbin, ChinaScience and Technology on Communication Networks Laboratory, Shijiazhuang, ChinaChannel estimation is one of the most important aspects of wireless communication. Especially, in sparse code multiple access (SCMA) system, the accuracy of channel estimation has a significant impact on decoding performance. Various methods, so far, have been developed for channel estimation. Most of these methods regard channel estimation as a parameter estimation problem of linear models. However, these methods require lots of time–frequency resources to ensure high estimation accuracy. In massive connection scenarios, high pilot overhead makes the spectrum resource more scarce. Therefore, the drawback of conventional channel estimation methods limits the further improvement of system capacity in the Internet of Things (IoT) when time–frequency resources are restricted. To address this problem, in this paper, we propose an efficient channel estimation scheme and sparse pilot structure design method in an SCMA system based on complex-valued sparse autoencoder which is effective to learn features of the wireless channel. Complex-valued sparse autoencoder is a kind of neural network with complex-valued weights. It contains two parts: encoder and decoder. In this paper, the encoder part is used to realize the pilot design. Channel estimation is implemented by the decoder. Complex-valued weights obtained from training are used as baseband pilots. Compared with maximum likelihood channel estimation (MLE) of the linear model, the proposed method can achieve higher channel estimation accuracy with more sparse pilot structure. The bit-error rates’ performance of the SCMA receiver in this paper is very close to that of the perfect channel state information (CSI).https://ieeexplore.ieee.org/document/8667100/Sparse code multiple accesschannel estimationsparse pilot structureInternet of Thingsmassive connectioncomplex-valued sparse autoencoder
spellingShingle Quan Yuan
Dezhi Li
Zhenyong Wang
Chang Liu
Ci He
Channel Estimation and Pilot Design for Uplink Sparse Code Multiple Access System Based on Complex-Valued Sparse Autoencoder
IEEE Access
Sparse code multiple access
channel estimation
sparse pilot structure
Internet of Things
massive connection
complex-valued sparse autoencoder
title Channel Estimation and Pilot Design for Uplink Sparse Code Multiple Access System Based on Complex-Valued Sparse Autoencoder
title_full Channel Estimation and Pilot Design for Uplink Sparse Code Multiple Access System Based on Complex-Valued Sparse Autoencoder
title_fullStr Channel Estimation and Pilot Design for Uplink Sparse Code Multiple Access System Based on Complex-Valued Sparse Autoencoder
title_full_unstemmed Channel Estimation and Pilot Design for Uplink Sparse Code Multiple Access System Based on Complex-Valued Sparse Autoencoder
title_short Channel Estimation and Pilot Design for Uplink Sparse Code Multiple Access System Based on Complex-Valued Sparse Autoencoder
title_sort channel estimation and pilot design for uplink sparse code multiple access system based on complex valued sparse autoencoder
topic Sparse code multiple access
channel estimation
sparse pilot structure
Internet of Things
massive connection
complex-valued sparse autoencoder
url https://ieeexplore.ieee.org/document/8667100/
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AT zhenyongwang channelestimationandpilotdesignforuplinksparsecodemultipleaccesssystembasedoncomplexvaluedsparseautoencoder
AT changliu channelestimationandpilotdesignforuplinksparsecodemultipleaccesssystembasedoncomplexvaluedsparseautoencoder
AT cihe channelestimationandpilotdesignforuplinksparsecodemultipleaccesssystembasedoncomplexvaluedsparseautoencoder