A Survey on Optimal Channel Estimation Methods for RISAided Communication Systems
Abstract
:1. Introduction
2. System Models for RISAssisted Systems
2.1. MISO Systems
2.1.1. System Model
2.1.2. Problem Formulation
2.2. MIMO Systems
2.2.1. CellFree Communication System
 Scenario Caption and Signal Model
 Channel Model of CellFree Communication System
2.2.2. Cell Communication System
 Channel Model
 Channel Aging
3. Channel Estimation in the RISAssisted Communication Systems
3.1. SCSI and ICSI
3.2. MISO Systems
3.2.1. Alternating Optimization with the Semidefinite Relaxation (SDR) Technique
3.2.2. PPO Algorithm
3.2.3. Pseudocode of Asynchronous OneStep QLearning
3.3. MIMO Systems
3.3.1. ThreeDimensional Multiple Measurement Vector (3DMMV) and the Look Ahead Orthogonal Match Pursuit (3DMLAOMP) Algorithm
3.3.2. TwoStage Based Cascaded Channel Estimation for a MultiUser System
3.3.3. Algorithm for an RISAssisted ABHBF System
3.3.4. Channel Estimation Algorithms for the Cases with LongTerm Imperfection (LTI) and ShortTerm Imperfection (STI)
4. Results of the Proposed Algorithms
4.1. MISO Systems
4.2. MIMO Systems
5. Conclusions
Author Contributions
Funding
Institutional Review Board Statement
Informed Consent Statement
Data Availability Statement
Acknowledgment
Conflicts of Interest
Abbreviations
1D  1 dimension 
3D  3 dimensions 
3DMLAOMP  3DMMV look ahead orthogonal match pursuit 
3DMMV  Threedimensional multiple measurement vector 
6G  Sixthgeneration 
A2C  Asynchronous Advantage Actor–critic 
ABHBF  Angularbased Hybrid Beamforming 
ADMM  Alternating Direction Method Of Multipliers 
ALS  Alternating Least Squares 
AO  Alternating Optimization 
AoA  Angle of Arrival 
AoD  Angle of Departure 
BB  Baseband 
BS  Base Station 
CPI  Conservative Policy Iteration 
CPU  Central Processing Unit 
CS  Compression Sensing 
CSI  Channel State Information 
DE  Deterministic Equivalent 
DFT  Discrete Fourier Transform 
DQN  Deep Qnetworks 
EM  Expectation Maximization 
FDD  Frequency Division Duplex 
GAE  Generalized Advantage Estimator 
HBF  Hybrid Beamforming 
HOSVD  Higherorder Singular Value Decomposition 
HRIS  Hybrid RIS 
ICSI  Instantaneous CSI 
IoVs  Internet of Vehicles 
JCEDD  Joint Channel Estimation and Data Detection 
KL  Kullback–Leibler 
LMMSE  Linear MMSE 
LoS  Line of Sight 
LS  Least Squares 
LTI  Longterm Imperfection 
MDP  Markov Decision Process 
MIMO  Multiple InputMultiple Output 
MISO  Multiple InputSingle Output 
mMIMO  massive Multiple InputMultiple Output 
MMSE  Minimum MSE 
MMV  Multiple Measurement Vector 
MP  Message Passing 
MSE  MeanSquaredError 
MUMISO  multiuser MISO 
NLoS  Nonlineofsight 
OMP  Orthogonal Matching Pursuit 
OTFS  Orthogonal Time Frequency Space 
PARAFAC  Parallel Factor 
PDD  Penalty Double Decomposition 
PDS  Primal Double Degradation 
PPO  Proximal Policy Optimization 
QoS  Quality of Service 
RBM  Reflecting Beamforming Matrix 
RF  Radio Frequency 
RIS  Reconfigurable Intelligent Surface 
RL  Reinforcement Learning 
RZF  Regularized ZF 
SCSI  Statistical CSI 
SE  Spectral Efficiency 
SINR  SignaltoInterferencePlusNoise Ratio 
STI  Shortterm Imperfection 
SVD  Singular Value Decomposition 
TALS  Trilinear ALS 
TDD  Time Division Duplex 
TORCS  The Open Racing Car Simulator 
TRPO  Trust Region Policy Optimization 
UE  User Equipment 
ULA  Uniform Linear Array 
UPA  Uniform Planar Arrays 
ZF  Zero Forcing 
SDR  Semidefinite Relaxation 
SCA  Successive Convex Approximation 
DSOMP  DoubleStructuredOMP 
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System Setup  Antenna Setup  Main Results 

Singleuser, narrowband  MISO  
MIMO 
 
Multiuser, narrowband  MISO  
Singleuser, broadband  MISO 

MIMO 
 
Multiuser, broadband  MISO  
MIMO 
Antenna Setup  Contributions  Pilot Overhead/Complexity  Method’s Name  Future Research/Results  Source 

MISO 


 [74]  
MISO 



 [4] 
MISO 


 [92]  
MIMO 



 [1] 
MIMO 



 [80] 
MIMO 



 [79] 
MIMO 


 [17]  
MIMO 



 [2] 
MIMO 



 [26] 
 
MIMO 



 [25] 
MIMO 



 [3] 
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Drampalou, S.F.; Miridakis, N.I.; Leligou, H.C.; Karkazis, P.A. A Survey on Optimal Channel Estimation Methods for RISAided Communication Systems. Signals 2023, 4, 208234. https://doi.org/10.3390/signals4010012
Drampalou SF, Miridakis NI, Leligou HC, Karkazis PA. A Survey on Optimal Channel Estimation Methods for RISAided Communication Systems. Signals. 2023; 4(1):208234. https://doi.org/10.3390/signals4010012
Chicago/Turabian StyleDrampalou, Stamatia F., Nikolaos I. Miridakis, Helen C. Leligou, and Panagiotis A. Karkazis. 2023. "A Survey on Optimal Channel Estimation Methods for RISAided Communication Systems" Signals 4, no. 1: 208234. https://doi.org/10.3390/signals4010012