scholarly journals A Comprehensive Performance Analysis of MIMO-OFDM Technology Using Different MIMO Configurations and M-QAM Modulation Schemes for LTE Cellular Network

2018 ◽  
Vol 12 (4) ◽  
pp. 118 ◽  
Author(s):  
Jobaida Akhtar ◽  
Mohammad Istiaque Reja ◽  
Md. Al Amin ◽  
Md. Sahidur Rahman
Keyword(s):  
Bit Error Rate ◽  
Error Rate ◽  
Orthogonal Frequency Division Multiplexing ◽  
Multiple Input Multiple Output ◽  
Frequency Synchronization ◽  
Antenna Diversity ◽  
Qam Modulation ◽  
Mimo Ofdm ◽  
Modulation Schemes ◽  
Ber Performance

MIMO-OFDM (Multiple Input Multiple Output-Orthogonal Frequency Division Multiplexing) uses multiple antennas at transmitter and receiver side to facilitate high throughput performance without needing additional bandwidth or transmission power. But frequency synchronization, Inter Carrier Interference (ICI) minimization and antenna diversity are the main challenges for MIMO-OFDM wireless technology. In this paper, a MIMO-OFDM hybrid model is designed with proper frequency synchronization and antenna diversity that minimizes ICI with improved signal strength. Using the model a comprehensive analysis in terms of Bit Error Rate (BER) performance with respect to Signal to Noise Ratio (SNR) and Bit Rate for different M-ary QAM modulation schemes and different MIMO configurations are presented over Rayleigh fading and AWGN channel. After an extensive analysis, it is found that the propose OFDM scheme shows better Bit Error rate (BER) performance for 64-QAM than any other M-ary QAM modulation schemes and the optimum MIMO configuration for this good quality performance is found to be 3×2 configuration.

Factors Influencing the PAPR Performance of OFDM and MIMO-OFDM Systems

2019 ◽  
Vol 11 (3) ◽  
pp. 23-33 ◽  
Author(s):  
Tahreer Mahmood ◽  
Seshadri Mohan
Keyword(s):  
Orthogonal Frequency Division Multiplexing ◽  
Multiple Input Multiple Output ◽  
Average Power ◽  
Channel Fading ◽  
Ofdm Systems ◽  
Practical Applications ◽  
Factors Influencing ◽  
Mimo Ofdm ◽  
Modulation Schemes ◽  
Papr Performance

Multiple-input multiple-output technology together with orthogonal frequency division multiplexing (MIMO-OFDM) is an effective technique to combat multi-channel fading and to improve bandwidth efficiency. Simultaneously, it also increases the system's ability to provide reliable transmission. However, the main disadvantage of OFDM is the high peak-to-average-power ratio (PAPR), which, if not mitigated, will negatively impact practical applications. The high PAPR increases complexity and Bit Error Rate. In this research, the authors investigate the factors influencing the PAPR performance of both OFDM and MIMO-OFDM systems. The objective of this research is to make researchers in this field become familiar with this problem as well as to impart an understanding of the factors that influence PAPR. In this study, the authors classify the factors that impact PAPR into modulation schemes and a number of sub-carriers. These parameters influence the PAPR performance have been analyzed and simulated by using MATLAB. It is observed that the numbers of sub-carriers have a great effect on the PAPR performance. However, modulation schemes can have a small effect on PAPR performance.

Time and Frequency Synchronization for MIMO-OFDM Systems

2013 ◽  
Vol 321-324 ◽  
pp. 2888-2891
Author(s):  
Jing Peng Gao ◽  
Chao Qun Wu ◽  
Dan Feng Zhao
Keyword(s):  
Orthogonal Frequency Division Multiplexing ◽  
Carrier Frequency Offset ◽  
Time Synchronization ◽  
Multiple Input Multiple Output ◽  
Frequency Offset ◽  
Time Instant ◽  
Frequency Synchronization ◽  
Ofdm Systems ◽  
Frequency Offset Estimation ◽  
Mimo Ofdm

Any carrier frequency offset will cause a loss of subcarrier orthogonality which results in ICI and hence performance degrades severely in MIMO-OFDM systems. In this paper, a time and frequency synchronization solution for multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) systems is proposed. The synchronization is achieved using one Constant Amplitude Zero Auto Correlation (CAZAC) sequence-based preamble which is simultaneously transmitted from all transmit antennas in the same OFDM time instant. The synchronization is accomplished sequentially by coarse time synchronization, fractional frequency offset estimation, integral frequency offset estimation and fine time synchronization. The simulation shows that the proposed algorithm can estimate the timing and frequency offsets efficiently in MIMO-OFDM systems, especially in low signal-to-noise ratio condition.

scholarly journals Smoothing techniques for decision-directed MIMO OFDM channel estimation

2011 ◽  
Vol 9 ◽  
pp. 139-143
Author(s):  
P. Beinschob ◽  
U. Zölzer
Keyword(s):  
Channel Estimation ◽  
Bit Error Rate ◽  
Error Rate ◽  
Error Propagation ◽  
Orthogonal Frequency Division Multiplexing ◽  
Mimo Systems ◽  
Smoothing Techniques ◽  
Time Frequency ◽  
Channel Estimate ◽  
Mimo Ofdm

Abstract. With the purpose of supplying the demand of faster and more reliable communication, multiple-input multiple-output (MIMO) systems in conjunction with Orthogonal Frequency Division Multiplexing (OFDM) are subject of extensive research. Successful Decoding requires an accurate channel estimate at the receiver, which is gained either by evaluation of reference symbols which requires designated resources in the transmit signal or decision-directed approaches. The latter offers a convenient way to maximize bandwidth efficiency, but it suffers from error propagation due to the dependency between the decoding of the current data symbol and the calculation of the next channel estimate. In our contribution we consider linear smoothing techniques to mitigate error propagation by the introduction of backward dependencies in the decision-based channel estimation. Designed as a post-processing step, frame repeat requests can be lowered by applying this technique if the data is insensitive to latency. The problem of high memory requirements of FIR smoothing in the context of MIMO-OFDM is addressed with an recursive approach that acquires minimal resources with virtual no performance loss. Channel estimate normalized mean square error and bit error rate (BER) performance evaluations are presented. For reference, a median filtering technique is presented that operates on the MIMO time-frequency grids of channel coefficients to reduce the peak-like outliers produced by wrong decisions due to unsuccessful decoding. Performance in terms of Bit Error Rate is compared to the proposed smoothing techniques.

Comparative Analysis of QAM Modulation Techniques over AWGN and Fading Channels

2021 ◽  
Vol 107 ◽  
pp. 194-200
Author(s):  
Theman Ibrahim Jirnadu ◽  
Adeyemi Abel Ajibesin ◽  
Ahmed T. Ishaq
Keyword(s):  
Fading Channels ◽  
Bit Error Rate ◽  
Error Rate ◽  
Signal To Noise Ratio ◽  
Research Work ◽  
Noise Spectral Density ◽  
Energy Consumption Optimization ◽  
Qam Modulation ◽  
Efficient Scheme ◽  
Modulation Schemes

Although, most researchers focus on some of the key components of good digital wireless communications which are the Bit Error Rate (BER) versus Signal to Noise Ratio (SNR) of modulation schemes. Energy consumption optimization is necessary for enhancing the performance of a wireless communication system as it offers numerous advantages to the system and the users. Therefore, this research focuses on analyzing the efficiency in the performance of the various QAM Modulation Schemes (4QAM, 16QAM, 32QAM & 64QAM) as they travel over noise/fading channels with the quest to obtain an energy-efficient scheme which will enhance system performance in terms of system runtime and quality of service. The efficiency of any given process, operation, or device is rated per the energy it consumes in carrying out an activity per unit output. Hence, the objective of this research work is to study and analyze comparatively the efficiency of these modulation schemes and to conclude with the most efficient scheme over the various channels. The evaluation of the Bit Error Rate (BER) versus energy per bit to noise spectral density (EbNo) for each communication scenario was carried out in MATLAB.

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 Performance Enhancement of MIMO-OFDM using Redundant Residue Number System

2018 ◽  
Vol 8 (5) ◽  
pp. 3902
Author(s):  
M. I. Youssef ◽  
A. E. Emam ◽  
M. Abd Elghany
Keyword(s):  
Bit Error Rate ◽  
Error Rate ◽  
Error Detection ◽  
Orthogonal Frequency Division Multiplexing ◽  
Number System ◽  
Residue Number System ◽  
Error Detection And Correction ◽  
Residue Number ◽  
Mimo Ofdm ◽  
Redundant Residue Number System

Telecommunication industry requires high capacity networks with high data rates which are achieved through utilization of Multiple-Input-Multiple-Output (MIMO) communication along with Orthogonal Frequency Division Multiplexing (OFDM) system. Still, the communication channel suffers from noise, interference or distortion due to hardware design limitations, and channel environment, and to combat these challenges, and achieve enhanced performance; various error control techniques are implemented to enable the receiver to detect any possible received errors and correct it and thus; for a certain transmitted signal power the system would have lower Bit Error Rate (BER). The provided research focuses on Redundant Residue Number System (RRNS) coding as a Forward Error Correction (FEC) scheme that improves the performance of MIMO-OFDM based wireless communications in comparison with current methods as Low-Density Parity Check (LDPC) coders at the transmitter side or equalizers at receiver side. The Bit Error Rate (BER) performance over the system was measured using MATLAB tool for different simulated channel conditions, including the effect of signal amplitude reduction and multipath delay spreading. Simulation results had shown that RRNS coding scheme provides an enhancement in system performance over conventional error detection and correction coding schemes by utilizing the distinct features of Residue Number System (RNS).

scholarly journals Experimental Evaluation of Machine learning based MIMO-OFDM System for Optimal PAPR and BER

2021 ◽  
Vol 16 ◽  
pp. 315-327
Author(s):  
Y. K Shobha ◽  
H. G Rangaraju
Keyword(s):  
Machine Learning ◽  
Error Rate ◽  
Communication Systems ◽  
Orthogonal Frequency Division Multiplexing ◽  
Multiple Input Multiple Output ◽  
Average Power ◽  
Low Complexity ◽  
Spatial Multiplexing ◽  
Operational Cost ◽  
Mimo Ofdm

The hypothetically convenient structure is the Multiple-Input Multiple-Output Orthogonal Frequency Division Multiplexing (MIMO-OFDM) technique that is employed for upcoming generations in wireless communication systems. Some of the benefits offered by MIMO-OFDM are enhanced spatial multiplexing, reliability and network throughput, and so on. Due to the integration of spatial antenna that is based on multi-stream, the problems which are related to significantly high power takes place in the system of OFDM and provides complex processing strategies. Some of the popularly known systems that are used for standardizing the Peak to average power ratio (PAPR) are partial transmit sequences (PTS), adoptive tone reservation (ATR), probabilistic mapping, and clipping which are required to be truncated and aims for minimizing the operational cost. The framework of hybrid Selective Mapping (SLM)-PTS proposed in this paper minimizes the operational cost by integrating strategies of PTS and SLM. A reduction approach that is suitable for PAPR and BER are chosen for optimization purposes depending on the statistical threshold constraint of PAPR and Bit Error Rate (BER). Thus, the system preferred with the help of the machine learning technique demonstrates the efficiency in implementing a generalized strategy to evaluate a low complexity MIMO-OFDM model. Ultimately, with the help of the PAPR and BER techniques-driven from value bound the performance of the error rate is evaluated in this framework that interactively changes from one technique.

scholarly journals Mimo System using16 Psk and Bpsk Modulation Schemes

2020 ◽  
Vol 9 (4) ◽  
pp. 895-897
Keyword(s):  
Bit Error Rate ◽  
Error Rate ◽  
Mimo System ◽  
Current Technology ◽  
Binary Modulation ◽  
Mimo Ofdm ◽  
Modulation Schemes ◽  
Bpsk Modulation

Current technology will build on signals mutual independent recurrence Technique(Orthogonal frequency divison multiplexing) and we don’t know the quality of it altogether expanded in numerous inputs numerous yields like Multi Input Multi output , Taking a shot at the same objective we use the LDPC based MIMO-OFDM with 16PSK and Binary modulation schemes. The bit error rate is checked so that we identify the which scheme is best.

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