scholarly journals ANALISIS UNJUK KERJA ZERO FORCING EQUALIZER PADA SISTEM OFDM MIMO

2018 ◽  
Vol 5 (1) ◽  
pp. 68
Author(s):  
R. A. Prayitno ◽  
N.M.A.E.D. Wirastuti ◽  
I.G.A.K.D.D. Hartawan
Keyword(s):  
No Value ◽  
Orthogonal Frequency Division Multiplexing ◽  
Mimo System ◽  
Multipath Propagation ◽  
Multiple Input Multiple Output ◽  
Ideal Point ◽  
Zero Forcing ◽  
Eye Diagram ◽  
Eye Pattern ◽  
The Ideal

Wireless network is one of the most important things in the development of telecommunication. However, the existing wireless technology has not been able to efficiently create a very high data rate because it was very sensitive to fading. Therefore, Orthogonal Frequency Division Multiplexing (OFDM) technology combined with MIMO (Multiple Input Multiple Output) transceiver system was used to gain more diversity and bandwidth efficiency. The propagation performed on the OFDM MIMO system was multipath propagation. To reduce Intersymbol Interference (ISI) was used Zero Forcing (ZF) equalizer which works by combining channel response and equalizer response itself to eliminate ISI. This study aims to determine the effect of Zero Forcing Equalizer on OFDM MIMO system using rayleigh fading channel and compared the result with OFDM MIMO STBC system. The research method used was simulation using MatLab R2015a. The simulation results showed that the performance of OFDM MIMO ZF system was worse than OFDM MIMO STBC system i.e BER vs EbNo simulation, eye diagram simulation, and constellation diagram simulation. The OFDM MIMO ZF system was required an Eb / No value more than 25 dB to achieve BER 10-4 while the OFDM MIMO STBC system only required an Eb / No value of 10.5 dB to achieve BER 10-4. The eye pattern generated by the OFDM MIMO ZF system was more closed and the dispersion of constellation signals away from the ideal point while OFDM MIMO STBC system displayed a more open eye pattern and the dispersion of its constellation signal closer to the ideal point. It indicated more ISI occurs in the OFDM MIMO ZF system than that in OFDM MIMO STBC system.

scholarly journals Implementation of a Zero-Forcing Precoding Algorithm Combined with Adaptive Beamforming Based on WiMAX System

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Hyunwook Yang ◽  
Seungwon Choi
Keyword(s):  
Mimo System ◽  
Multiple Input Multiple Output ◽  
Experimental System ◽  
Multiple Access Interference ◽  
Adaptive Beamforming ◽  
Base Station ◽  
Zero Forcing ◽  
Single Antenna ◽  
Input Multiple Output ◽  
Wimax System

We propose a novel precoding algorithm that is a zero-forcing (ZF) method combined with adaptive beamforming in the Worldwide Interoperability for Microwave Access (WiMAX) system. In a Multiuser Multiple-Input Multiple-Output (MU-MIMO) system, ZF is used to eliminate the Multiple Access Interference (MAI) in order to allow several users to share a common resource. The adaptive beamforming algorithm is used to achieve the desired SNR gain. The experimental system consists of a WiMAX base station that has 2 MIMO elements, each of which is composed of three-array antennas and two mobile terminals, each of which has a single antenna. Through computer simulations, we verified that the proposed method outperforms the conventional ZF method by at least 2.4 dB when the BER is 0.1%, or 1.7 dB when the FER is 1%, in terms of the SNR. Through a hardware implementation of the proposed method, we verified the feasibility of the proposed method for realizing a practical WiMAX base station to utilize the channel resources as efficiently as possible.

A companding approach for PAPR suppression in OFDM based massive MIMO system

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Ajay Kumar Yadav ◽  
Pritam Keshari Sahoo ◽  
Yogendra Kumar Prajapati
Keyword(s):  
Massive Mimo ◽  
Orthogonal Frequency Division Multiplexing ◽  
Mimo System ◽  
Multiple Input Multiple Output ◽  
Average Power ◽  
Base Station ◽  
Convex Optimization Problem ◽  
Multiple Input ◽  
Input Multiple Output ◽  
Mimo Ofdm

Abstract Orthogonal frequency division multiplexing (OFDM) based massive multiuser (MU) multiple input multiple output (MIMO) system is popularly known as high peak-to-average power ratio (PAPR) issue. The OFDM-based massive MIMO system exhibits large number of antennas at Base Station (BS) due to the use of large number of high-power amplifiers (HPA). High PAPR causes HPAs to work in a nonlinear region, and hardware cost of nonlinear HPAs are very high and also power inefficient. Hence, to tackle this problem, this manuscript suggests a novel scheme based on the joint MU precoding and PAPR minimization (PP) expressed as a convex optimization problem solved by steepest gradient descent (GD) with μ-law companding approach. Therefore, we develop a new scheme mentioned to as MU-PP-GDs with μ-law companding to minimize PAPR by compressing and enlarging of massive MIMO OFDM signals simultaneously. At CCDF = 10−3, the proposed scheme (MU-PP-GDs with μ-law companding for Iterations = 100) minimizes the PAPR to 3.70 dB which is better than that of MU-PP-GDs, (iteration = 100) as shown in simulation results.

scholarly journals SCMA-MIMO system with adaptation to the channel state

2021 ◽  
Vol 2134 (1) ◽  
pp. 012025
Author(s):  
Dmitriy Pokamestov ◽  
Yakov Kryukov ◽  
Eugeniy Rogozhnikov ◽  
Islam Kanatbekuli ◽  
Edgar Dmitriyev
Keyword(s):  
Communication System ◽  
Orthogonal Frequency Division Multiplexing ◽  
Multiple Access ◽  
Mimo System ◽  
Multiple Input Multiple Output ◽  
Network Resources ◽  
Multiple Input ◽  
The Matrix ◽  
High Spectral Efficiency ◽  
Input Multiple Output

Abstract Sparse code multiple access (SCMA) is one of the promising implementations of non-orthogonal multiple access (NOMA) methods. SCMA provides high spectral efficiency and a large number of network resources. We describe a communication system with SCMA, space-time block coding (STBC), multiple input multiple output (MIMO) technology, and orthogonal frequency division multiplexing (OFDM). The architecture of such systems, including algorithms of formation and processing of signals is considered. A method for adapting signals to the state of the spatial channel transmission based on information about the matrix of channel coefficients is proposed. The application of such adaptation allows to compensate the influence of the channel and to reduce the probability of bit errors. We consider the bit error rate (BER) performance of the communication system in different channel models and show the effectiveness of the proposed methods.

scholarly journals Performance Analysis of MIMO System over an In-home PLC Channel

2021 ◽  
Vol 15 ◽  
pp. 1-10
Author(s):  
Mohammed EL GHZAOUI
Keyword(s):  
Orthogonal Frequency Division Multiplexing ◽  
Low Voltage ◽  
Impulsive Noise ◽  
Mimo System ◽  
Minimum Mean Square Error ◽  
Multiple Input Multiple Output ◽  
High Data ◽  
Communication Links ◽  
Input Multiple Output ◽  
Grid Applications

Power line communication (PLC) system is an attractive technology for Smart Grid applications. One key benefit of PLC is its low installation cost because, in PLC technology, we do not need to install any extra cable to extend a network due to the accessibility to low voltage power network. Orthogonal frequency division multiplexing (OFDM) is widely used in PLC networks. Currently, Multiple Input Multiple Output (MIMO) technology is one of the processing techniques appropriate to PLC networks, allowing high data rate. In this work, the MIMO-OFDM system is established to provide better performance over the PLC system by providing communication links with substantial diversity and capacity. However, adapting MIMO to the PLC network involves solving several issues such as MIMO PLC channel modelling and optimisation of the modulation parameters. In this paper, we present measurements results of the transfer function and impulsive noise in the extended frequency range 2-100 MHz. In the simulation part, we evaluate the performance of the proposed receivers in 2×2 MIMO-PLC channels. It is shown that the minimum mean square error (MMSE) receiver can be one of the appropriate candidates for MIMO PLC channels due to its bite error rate (BER) characteristics under impulsive noise.

scholarly journals Implementation of an Adaptive MIMO System using Effective Minimization of Frame Error Rate

2020 ◽  
Vol 9 (4) ◽  
pp. 2290-2295
Keyword(s):  
Wireless Communication ◽  
Error Rate ◽  
Mimo System ◽  
Multipath Propagation ◽  
Multiple Input Multiple Output ◽  
Adaptation Algorithm ◽  
Frame Error Rate ◽  
Communication Techniques ◽  
Simulink Model ◽  
4G Lte

Paper Multiple Input Multiple Output (MIMO) is a technique which is now being widely used for wireless communication techniques such as 4G LTE. MIMO uses multiple antennas at the transmitter as well as at the receiver side in order to improve spectral efficiency although it increases the system complexity. Multipath propagation, which is the drawback for wireless communication, is used as an advantage in MIMO. This paper presents a model of Adaptive MIMO system in Simulink. The system adapts to specific transmit and receive diversity depending on the frame error rate. The proposed system uses 4 transmitting and receiving antennas, the number of antennas change as per the adaptation algorithm. The data is sent in the form of frames with each frame carrying the desired number of bits. Here, we have implemented the Orthogonal Space-Time Block Coding (OSTBC) scheme in a MATLAB Simulink model and implemented an adaptive algorithm to change the quantity of transmitting and receiving antennas depending on the frame error rate (FER) value.

scholarly journals Fractional weighted ZF equalizer: A novel approach for channel equalization in MIMO-OFDM system under impulse noise environment

2021 ◽  
Vol 6 (1) ◽  
pp. 1-10
Author(s):  
S. P. Girija ◽  
Rameshwar Rao
Keyword(s):  
Error Rate ◽  
Orthogonal Frequency Division Multiplexing ◽  
Impulse Noise ◽  
Multiple Input Multiple Output ◽  
Symbol Error Rate ◽  
Mitigation Strategy ◽  
Ofdm System ◽  
Noise Mitigation ◽  
Zero Forcing ◽  
Mimo Ofdm

Impulse noise is the major factor degrading the performance of the wireless system, imposing the need for the impulse noise mitigation strategy. Mainly, in the multiple-input multiple-output (MIMO) and orthogonal frequency-division multiplexing (OFDM) system contaminated with the impulse noise creates a major impact in the performance as the conventional zero-forcing (ZF) equalizer as there is no satisfactory results. Thus, the paper concentrates on the impulse noise mitigation strategy based on the fractional weighed zero-forcing (FWZF) equalizer, which is the integration of the fractional concept in the Zero-Forcing equalizer. The noise impacts in the MIMO-OFDM system are minimized and the performance is enhanced due to the usage of the fractional theory in the ZF equalizer as the equalization values of the previous instances are interpreted for the formulation of the effective equalization value in the current instance of the ZF equalizer. The performance of the methods is done based on the valuation metrics, Bit Error Rate (BER), Mean Square Error (MSE), and Symbol Error Rate (SER) with respect to the Signal-to-Noise Ratio (SNR) and dissimilar antenna array size. It is found that the proposed Fractional Weighed Zero-Forcing equalizer outperformed the existing methods with a minimal BER and SER of 0.063, and 0.1038 while analyzing the methods in the Rayleigh environment.

scholarly journals Three-Dimensional Target Localization and Cramér-Rao Bound for Two-Dimensional OFDM-MIMO Radar

2017 ◽  
Vol 2017 ◽  
pp. 1-14 ◽  
Author(s):  
Xingxing Li ◽  
Dangwei Wang ◽  
Xiaoyan Ma
Keyword(s):  
Orthogonal Frequency Division Multiplexing ◽  
Mimo System ◽  
Multiple Input Multiple Output ◽  
Three Dimensional ◽  
Mimo Radar ◽  
Joint Estimation ◽  
Target Localization ◽  
Two Dimensional ◽  
Frequency Diversity ◽  
Cramer Rao Bound

Target localization using a frequency diversity multiple-input multiple-output (MIMO) system is one of the hottest research directions in the radar society. In this paper, three-dimensional (3D) target localization is considered for two-dimensional MIMO radar with orthogonal frequency division multiplexing linear frequency modulated (OFDM-LFM) waveforms. To realize joint estimation for range and angle in azimuth and elevation, the range-angle-dependent beam pattern with high range resolution is produced by the OFDM-LFM waveform. Then, the 3D target localization proposal is presented and the corresponding closed-form expressions of Cramér-Rao bound (CRB) are derived. Furthermore, for mitigating the coupling of angle and range and further improving the estimation precision, a CRB optimization method is proposed. Different from the existing methods of FDA-based radar, the proposed method can provide higher range estimation because of multiple transmitted frequency bands. Numerical simulation results are provided to demonstrate the effectiveness of the proposed approach and its improved performance of target localization.

scholarly journals An Adaptive Power and Bit Allocation Algorithm for MIMO OFDM/SDMA System Employing Zero-Forcing Multi-user Detection

2006 ◽  
Vol 2 (2) ◽  
pp. 63
Author(s):  
Peerapong Uthansakul ◽  
Marek E Bialkowski
Keyword(s):  
Orthogonal Frequency Division Multiplexing ◽  
Multiple Input Multiple Output ◽  
Zero Forcing ◽  
Space Division Multiple Access ◽  
Multiple User ◽  
Input Multiple Output ◽  
Mimo Ofdm ◽  
One Step ◽  
User Access ◽  
Adaptive Power

The paper describes an adaptive algorithm for power and bit allocations in a multiple user Multiple Input Multiple Output Orthogonal Frequency Division Multiplexing (MIMO OFDM) system with Space Division Multiple Access, which operates in a frequency selective fading channel. The zero forcing (ZF) technique is applied to accomplish multi user detection (MUD). A Lagrange multiplier method is applied to obtain a one-step solution for optimal power and bit allocations in this system. The resulting algorithm is advantageous over an alternative Greedy algorithm, because it does not require a time-consuming iterative procedure for its implementation. The algorithm assigns bits and power for all users according to the channel state information (CSI), which is assumed to be fully or partially available to the transmitter. The simulation results show the proposed algorithm operates successfully in multiple user access scenarios.

scholarly journals A Novel Hybrid Block INF Diagonalization (HBID) Precoding Technique for Capacity Improvement in MU-MIMO-OFDM System

2019 ◽  
Vol 9 (1) ◽  
pp. 5369-5375
Keyword(s):  
Orthogonal Frequency Division Multiplexing ◽  
Mimo System ◽  
Multiple Input Multiple Output ◽  
Average Power ◽  
Threshold Value ◽  
Ofdm Systems ◽  
Ofdm System ◽  
Transmission Scheme ◽  
Mimo Ofdm ◽  
Sum Rate

In wireless communication system, the emerging technology is MU-Multiple Input Multiple Output-Orthogonal Frequency Division Multiplexing (MU-MIMO-OFDM). For minimizing Peak-to-Average Power Ratio (PAPR) in the uplink transmission scheme, OFDM is exploited in MIMO system and compared with Single Carrier-Frequency Domain Processing (SC-FDP). Further reducing the PAPR value, a new method is proposed Hybrid Block Inf Diagonalization (HBID) technique for an uplink OFDM system and calculated the less Bit Error Rate (BER). In this paper, the HBID precoding technique reduces PAPR with such amount and unwanted amplitude of the signal is to be cut down for a specific threshold value as 1.4 for best performance so that the PAPR value is reduced in considerable rate of OFDM then compared to SC-FDP system. Also, we compared the various precoding techniques with HBID method in MIMO-OFDM systems with various parameters such as BER, PAPR, Number of users, Sum rate. Finally, the proposed method reduces PAPR with 47% and BER with 50%, number of users with 49% and sum rate as 57%. HBID based precoding method shows its excellence with the lowest PAPR value and thereby enhance the presentation of the OFDM system

scholarly journals Performance Comparison of MIMO Technology over LTE-A System

2019 ◽  
Vol 12 (1) ◽  
pp. 120-125
Author(s):  
Khalid Hussein Rashid
Keyword(s):  
Orthogonal Frequency Division Multiplexing ◽  
Performance Metrics ◽  
Mimo System ◽  
Adaptive Modulation ◽  
Multiple Input Multiple Output ◽  
Performance Comparison ◽  
Spatial Multiplexing ◽  
Mimo Channel ◽  
Data Traffic ◽  
Maximum Throughput

Third generation partnership project (3GPP) has been introducing The Long Term Evolution (LTE) (release8) and LTE advance (LTE-A) (release 10)fourth generations as a new access technology to mobile communication in order to meet the tremendous requirement  of data traffic.   LTE-A have adopted modern techniques such as Multiple-Input Multiple Output (MIMO)and Orthogonal Frequency Division Multiplexing OFDM to satisfy all the requirements and meet the tremendous growth of data. LTE-A with MIMO system scheme based on transmission mode Close Loop Spatial Multiplexing (CLSM).CLSM  transmission modes used for doubling the bit stream and consequently increased the data rate with Adaptive modulation schemes. In this paper, The performance metrics considered are throughput. These are used to evaluate the performance of LTE-A in (AWGN) channel and Rayleigh Fading channel with detection schemes for CLSM with different band width (3, 5 and 10 MHz) and the following results has been obtained : at the same bandwidth (10 MHz) for 8x8 MIMO channel and AWGN at SNR (25dB) the maximum throughput equal(224.3 Mb/S) while in Rayleigh the throughput equal(203.8 Mb/S) . A MATLAB simulation version  R2013a has been used to complete the analysis and comparison.

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