scholarly journals SVD-Aided Beamforming and Power Allocation Algorithm for Multiuser Turbo-BLAST System Uplink with Imperfect CSI

2012 ◽  
Vol 2012 ◽  
pp. 1-13
Author(s):  
Xiaomin Chen ◽  
Xiangbin Yu ◽  
Dazhuan Xu
Keyword(s):  
Power Allocation ◽  
System Performance ◽  
Estimation Error ◽  
Channel Estimation Error ◽  
Iterative Detection ◽  
Receiver Design ◽  
Imperfect Csi ◽  
Channel State ◽  
Multiuser Interference ◽  
State Information

The SVD-aided joint transmitter and receiver design for the uplink of CDMA-based synchronous multiuser Turbo-BLAST systems is proposed in the presence of channel state information (CSI) imperfection. At the transmitter, the beamforming and power allocation schemes are developed to maximize the capacity of the desired user. At the receiver, a suboptimal decorrelating scheme is first proposed to mitigate the multiuser interference (MUI) and decouple the detection of different users with imperfect CSI, and then the iterative detecting algorithm that takes the channel estimation error into account is designed to cancel the coantenna interference (CAI) and enhance the bit error rate (BER) results further. Simulation results show that the proposed uplink CDMA-based multiuser Turbo-BLAST model is effective, the detection from every user is completely independent to each other after decorrelating, and the system performance can be enhanced by the proposed beamforming and power allocation schemes. Furthermore, BER performance can be enhanced by the modified iterative detection. The effect of CSI imperfection is evaluated, which is proved to be a useful tool to assess the system performance with imperfect CSI.

scholarly journals Impacts of Imperfect Channel State Information, Transceiver Hardware, and Self-Interference Cancellation on the Performance of Full-Duplex MIMO Relay System

Sensors ◽  
2020 ◽  
Vol 20 (6) ◽  
pp. 1671 ◽  
Author(s):  
Ba Cao Nguyen ◽  
Nguyen Nhu Thang ◽  
Xuan Nam Tran ◽  
Le The Dung
Keyword(s):  
System Performance ◽  
Interference Cancellation ◽  
Estimation Error ◽  
Full Duplex ◽  
Channel Estimation Error ◽  
Imperfect Channel State Information ◽  
Channel State ◽  
Relay System ◽  
State Information ◽  
Mimo Relay

Imperfect channel state information (I-CSI) and imperfect transceiver hardware often happen in wireless communication systems due to the time-varying and random characteristics of both wireless channels and hardware components. The impacts of I-CSI and hardware impairments (HI) reduce not only the system performance but also the self-interference cancellation (SIC) capability of full-duplex (FD) devices. To investigate the system performance in realistic scenarios, in this paper, we consider the performance of an FD multiple-input multiple-output (MIMO) relay system under the effects of I-CSI, imperfect SIC (I-SIC), and imperfect transceiver hardware. We mathematically derive the exact closed-form expressions of the outage probability (OP) and ergodic capacity of the considered HI-FD-MIMO relay system over Rayleigh fading channels with the existence of I-CSI, I-SIC, and HI. Numerical results indicate that the performance in terms of OP and capacity reaches saturation faster, especially when the channel estimation error, the residual self-interference (RSI), and HI levels are remarkable. Therefore, various solutions for effectively reducing the channel estimation error, RSI, and HI levels in the HI-FD-MIMO relay system should be carried out to improve the system performance. All derived mathematical expressions are verified through Monte-Carlo simulations.

scholarly journals An Algorithm That Predicts CSI to Allocate Bandwidth for Healthcare Monitoring in Hospital's Waiting Rooms

2012 ◽  
Vol 2012 ◽  
pp. 1-13 ◽  
Author(s):  
Di Lin ◽  
Fabrice Labeau
Keyword(s):  
System Performance ◽  
Bandwidth Allocation ◽  
Efficient Solution ◽  
Monitoring Systems ◽  
Central Unit ◽  
Imperfect Csi ◽  
Negative Effects ◽  
Channel State ◽  
State Information ◽  
Healthcare Monitoring

In wireless healthcare monitoring systems, bandwidth allocation is an efficient solution to the problem of scarce wireless bandwidth for the monitoring of patients. However, when the central unit cannot access the exact channel state information (CSI), the efficiency of bandwidth allocation decreases, and the system performance also decreases. In this paper, we propose an algorithm to reduce the negative effects of imperfect CSI on system performance. In this algorithm, the central unit can predict the current CSI by previous CSI when the current CSI is not available. We analyze the reliability of the proposed algorithm by deducing the standard error of estimated CSI with this algorithm. In addition, we analyze the efficiency of the proposed algorithm by discussing the system performance with this algorithm.

scholarly journals Power Optimization of Tilted Tomlinson-Harashima Precoder in MIMO Channels with Imperfect Channel State Information

2013 ◽  
Vol 2013 ◽  
pp. 1-6
Author(s):  
Hossein Khaleghi Bizaki ◽  
Morteza Khaleghi Hojaghan ◽  
Seyyed Mohammad Razavizadeh
Keyword(s):  
Channel State Information ◽  
Communication Systems ◽  
Estimation Error ◽  
Multiple Input Multiple Output ◽  
Channel Estimation Error ◽  
Imperfect Channel State Information ◽  
Mimo Channels ◽  
Channel State ◽  
State Information ◽  
Input Multiple Output

This paper concentrates on the designing of a robust Tomlinson-Harashima Precoder (THP) over multiple-input multiple-output (MIMO) channels in wireless communication systems with assumption of imperfect channel state information (CSI) at the transmitter side. With the assumption that the covariance matrix of channel estimation error is available at the transmitter side, we design a THP that presents robustness against channel uncertainties. In the proposed robust THP, the transmit power is further minimized by using the Tilted constellation concept. This power minimization reduces the interchannel Interference (ICI) between subchannels and, furthermore, recovers some part of the THP's power loss. The bit error rate (BER) of the proposed system is further improved by using a power loading technique. Finally, the simulation results compare the performance of our proposed robust THP with a conventional MIMO-THP.

scholarly journals SVD-Aided Power Allocation and Iterative Detection Scheme for Turbo-BLAST System with Imperfect Channel State Information

2011 ◽  
Vol 2011 ◽  
pp. 1-8 ◽  
Author(s):  
Xiaomin Chen ◽  
Xiangbin Yu ◽  
Dazhuan Xu
Keyword(s):  
Power Allocation ◽  
Channel State Information ◽  
Mimo Channel ◽  
Iterative Detection ◽  
Imperfect Channel State Information ◽  
Channel State ◽  
Detection Scheme ◽  
State Information ◽  
Adaptive Power ◽  
Ber Performance

A new technique that combines adaptive power allocation and iterative detection based on singular value decomposition (SVD) is introduced for the modified Turbo-BLAST system with imperfect channel state information (I-CSI). At the transmitter, in order to maximize the capacity performance, the MIMO channel is decomposed into several parallel eigen subchannels by SVD, and then proper power based on the water-filling principle is allocated to every subchannel subject to the total transmit power constraint. At the receiver, the modified MMSE detector taking the CSI imperfection into account is used to remove the coantenna interference, and then the turbo idea is employed for iterative detection to lower the system BER. As a result, the BER performance is effectively enhanced. Numerical results show that the introduced SVD-aided adaptive power allocation method is valid to improve not only the capacity but also the BER performance in the presence of channel state information imperfection, while the iterative detector can further lower the BER results.

scholarly journals On the Performance of Power Splitting Energy Harvested Wireless Full-Duplex Relaying Network with Imperfect CSI over Dissimilar Channels

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Tan N. Nguyen ◽  
Minh Tran ◽  
Phuong T. Tran ◽  
Phu Tran Tin ◽  
Thanh-Long Nguyen ◽  
...  
Keyword(s):  
System Performance ◽  
Estimation Error ◽  
Relay Node ◽  
Full Duplex ◽  
Channel Estimation Error ◽  
Power Splitting ◽  
Imperfect Csi ◽  
Amplify And Forward ◽  
Relay Nodes ◽  
Splitting Factor

The energy harvesting amplify-and-forward full-duplex relaying network over the dissimilar fading environments in imperfect CSI condition is investigated. In this system model, the energy, and information are transferred from the source to the relay nodes by the power splitting protocol with helping of the full-duplex relay node. Firstly, the outage probability, achievable throughput, and the optimal power splitting factor in terms of the analytical mathematical expressions were proposed, analyzed, and demonstrated. Furthermore, the system performance of the proposed model on the connection with all system parameters is rigorously studied. Finally, the numerical results demonstrated and convinced one that the analytical and the simulation results are matched well with each other for all system parameter values using Monte-Carlo simulation. The results show that the system performance degrades significantly but is still in a permissible interval while the channel estimation error increases and the system performance of the mixing scenarios is better in comparison with the Rayleigh-Rayleigh scenario.

scholarly journals ENERGY-EFFICIENT POWER ALLOCATION FOR IMPERFECT CSI DOWNLINK NOMA SYSTEM

2021 ◽  
Vol 11 (2) ◽  
pp. 118-129
Author(s):  
Reem Aldebes ◽  
Kaharudin Dimyati ◽  
Effariza Hanafi
Keyword(s):  
Energy Efficiency ◽  
Channel Estimation ◽  
Outage Probability ◽  
Power Allocation ◽  
Multiple Access ◽  
Estimation Error ◽  
Base Station ◽  
Channel Estimation Error ◽  
Imperfect Csi ◽  
Fifth Generation

The fifth generation (5G) networks must provide the massively increased number of users by thousand times higher data rate at lower power consumption. Thus, optimizing the energy efficiency (EE) becomes an essential issue that has to be researched from the green communication perspective. Non-orthogonal multiple access (NOMA) is considered one of the high potential techniques in fifth-generation systems. This technology is favorable to maximize the energy efficiency and the spectrum efficiency by composing different signals at the same time on the same carrier at different power levels. In this paper, a low complexity power allocation algorithm is proposed in imperfect channel state information (CSI) downlink NOMA cellular system, where obtaining full CSI at the base station is considered a challenge. The proposed algorithm relies on the fact that the allocated power is inversely proportional to the channel strength of the user to implement the successive interference cancellation (SIC) technique at the user terminal to reconstruct the desired signal. The performance of the system is analyzed in terms of energy efficiency and outage probability and compared to the conventional orthogonal multiple access (OMA) system. Results show that the proposed algorithm increases the energy efficiency by about 50% compared to the conventional OMA technology, and an improvement in the outage probability has been achieved. Furthermore, the effect of the error in the channel estimation on the energy efficiency in imperfect CSI NOMA system is evaluated. The simulation shows that the energy efficiency reduces when the channel estimation error increases; and the best performance is achieved in the perfect CSI case where the channel estimation error is zero.

scholarly journals Power Allocation for Secrecy-Capacity-Optimization-Artificial-Noise Secure MIMO Precoding Systems under Perfect and Imperfect Channel State Information

2021 ◽  
Vol 11 (10) ◽  
pp. 4558
Author(s):  
Yebo Gu ◽  
Bowen Huang ◽  
Zhilu Wu
Keyword(s):  
Channel Estimation ◽  
Power Allocation ◽  
Optimization Problem ◽  
Estimation Error ◽  
Channel Estimation Error ◽  
Artificial Noise ◽  
Secrecy Capacity ◽  
Transmission Power ◽  
Channel State ◽  
Imperfect Channel Estimation

In this paper, we consider the physical layer security problem of the wireless communication system. For the multiple-input, multiple-output (MIMO) wireless communication system, secrecy capacity optimization artificial noise (SCO−AN) is introduced and studied. Unlike its traditional counterpart, SCO−AN is an artificial noise located in the range space of the channel state information space and thus results in a significant increase in the secrecy capacity. Due to the limitation of transmission power, making rational use of this power is crucial to effectively increase the secrecy capacity. Hence, in this paper, the objective function of transmission power allocation is constructed. We also consider the imperfect channel estimation in the power allocation problems. In traditional AN research conducted in the past, the expression of the imperfect channel estimation effect was left unknown. Still, the extent to which the channel estimation error impacts the accuracy of secrecy capacity computation is not negligible. We derive the expression of channel estimation error for least square (LS) and minimum mean squared error (MMSE) channel estimation. The objective function for transmission power allocation is non-convex. That is, the traditional gradient method cannot be used to solve this non-convex optimization problem of power allocation. An improved sequence quadratic program (ISQP) is therefore applied to solve this optimization problem. The numerical result shows that the ISQP is better than other algorithms, and the power allocation as derived from ISQP significantly increases secrecy capacity.

Channel capacity analysis of non-orthogonal multiple access and massive multiple-input multiple-output wireless communication networks considering perfect and imperfect channel state information

2021 ◽  
pp. 154851292110001
Author(s):  
Ravi Shankar ◽  
Shovon Nandi ◽  
Ajay Rupani
Keyword(s):  
Multiple Access ◽  
Mimo System ◽  
Estimation Error ◽  
Multiple Input Multiple Output ◽  
Channel Estimation Error ◽  
Channel State ◽  
State Information ◽  
Multiple User ◽  
Multiple Input ◽  
Input Multiple Output

In this paper, we investigate the non-orthogonal multiple access (NOMA) and massive multiple-input multiple-output (M-MIMO) techniques and through simulation, and a comparison is given between the NOMA and orthogonal multiple access techniques. Integrating NOMA with M-MIMO is a very challenging task. In this paper, for a single-cell system, NOMA is integrated with a M-MIMO system for better spectral and energy efficiency. Investigation of the multiple user gain is the focus of this work because the multiple user gain supports simultaneous transmission of multiple users in the case of the M-MIMO system. In this way, the M-MIMO will provide a 100 times channel capacity increase, which results in very high data transmission rate. In the modern communication system, achieving multiple user gain is a very difficult task when channel estimation error is present. The performance of the orthogonal multiple access as well as NOMA system significantly reduced in the presence of channel estimation error. However, most of the current schemes do not work well with imperfect perfect channel state information conditions. Simulation results closely agree with the theoretical outcomes.

Iterative Detection Scheme for Turbo-BLAST System with Adaptive Power Allocation in the Presence of Channel State Information Imperfection

2013 ◽  
Vol 646 ◽  
pp. 120-125
Author(s):  
Xiao Min Chen ◽  
Xiao Dan Yu ◽  
Wei Tan ◽  
Xiang Bin Yu
Keyword(s):  
Channel Estimation ◽  
Power Allocation ◽  
Channel State Information ◽  
Iterative Detection ◽  
Channel State ◽  
Estimation Errors ◽  
Detection Scheme ◽  
State Information ◽  
Channel Estimation Errors ◽  
Optimal Power

We propose an iterative detection scheme for Turbo-BLAST system with optimal power allocation in the presence of channel state information imperfection. The proposed scheme uses the channel estimation matrix for detection and treats the interference caused by channel estimation errors and additive white Gaussian noise as equivalent noise where the channel estimation matrix and the statistical characteristic of channel estimation errors are necessitated. Simulation results show the proposed algorithm is effective to improve bit error rate (BER) performance through iterative detection for modified Turbo-BLAST system with optimal power allocation in the presence of imperfect channel state information.

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