scholarly journals Investigation and Suppression of RF Leakage Power in Front End Wireless Devices

2021 ◽  
Author(s):  
Kanchana Devi A ◽  
Bhuvaneswari B
Keyword(s):  
Orthogonal Frequency Division Multiplexing ◽  
Frequency Division ◽  
Ofdm Systems ◽  
Wireless Devices ◽  
Modulation And Demodulation ◽  
Front End ◽  
High Spectral Efficiency ◽  
Power Leakage ◽  
System Frequency ◽  
Isolation Performance

In this modern Communication Wireless System, Frequency Division Duplex (FDD) is mostly used. Duplex is a device to separate Transmitter and Receiver signals. Transmitter or Power leakage causes from limited isolation performance of the duplexer. Various Techniques of Modulation using Orthogonal Frequency Division Multiplexing (OFDM) provided better solution to cancel this leakage. The OFDM provides high spectral efficiency, lower multi-path distortion and to eliminate inter symbol interference (ISI). Fast Fourier Transform implemented modulation and demodulation functions more efficiently. Using simulation result of the various parameters are analysed. In addition, Comparison of the table between Bit rate error value, Signal strength throughput, Power consumption and Mean square error values obtained in the OFDM systems.

scholarly journals AN EFFICIENT METHOD FOR PAPR REDUCTION IN OFDM SYSTEMS WITH REDUCED COMPLEXITY

2013 ◽  
pp. 96-100
Author(s):  
PRITANJALI KUMARI ◽  
US TRIAR
Keyword(s):  
Orthogonal Frequency Division Multiplexing ◽  
Average Power ◽  
High Peak ◽  
Papr Reduction ◽  
Power Calculation ◽  
Frequency Division Multiplexing ◽  
Power Ratio ◽  
Frequency Division ◽  
Ofdm Systems ◽  
Reduced Complexity

Orthogonal Frequency Division Multiplexing (OFDM), widely used in digital wireless communication, has a major drawback of high Peak to Average Power Ratio (PAPR). A reduced complexity partial transmit sequence (PTS) scheme has been proposed to solve high peak to average power ratio (PAPR) of orthogonal frequency division multiplexing (OFDM) system. In the proposed PTS scheme, a function is generated by summing the power of time domain samples at time ‘n’ in each sub blocks, known as “Hn”.Only those samples, having Hn greater than or equal to a preset threshold value (αT) are used for peak power calculation during the process of selecting a candidate signal with the lowest PAPR for transmission. As compared to conventional PTS scheme, the proposed scheme achieves almost the same PAPR reduction performance with much lower computational complexity.

scholarly journals Spectral Efficiency of FBMC Over OFDM System

2019 ◽  
Vol 9 (2S3) ◽  
pp. 235-237
Keyword(s):  
Spectral Efficiency ◽  
Orthogonal Frequency Division Multiplexing ◽  
Filter Bank ◽  
Average Power ◽  
Primary Objective ◽  
Mobile Environments ◽  
Frequency Division ◽  
Doppler Shifts ◽  
Wireless Broadband ◽  
High Spectral Efficiency

Significant wireless broadband technology used in various cellular standards is Orthogonal Frequency Division Multiplexing (OFDM) which will make use of Multi Carrier Modulated (MCM) systems. Even though OFDM has numerous advantages, it is hard to employ OFDM for complex networks. It is very hard to establish synchronization in mobile environments as it is difficult to predict the Doppler shifts of different users, which results in inter carrier interference (ICI). Further, filters associated with OFDM carrier have comparatively large sidebands which outcomes in Out of Band (OOB) radiations. Insufficient spectral usage is provided by CP-OFDM by using more guard band. So the problems caused by traditional OFDM/CP-OFDM can be answered by employing a new system termed as Filter Bank Multi Carrier (FBMC) System. It is a form of MCM and it can be considered as an advanced cyclic-prefix (CP-OFDM). In OFDM, whole band gets filtered while in FBMC, each sub carrier band is independently filtered. The primary objective of this work is to relate the performance of 5G modulation technique such as FBMC against OFDM and to suggest an ideal waveform for 5G communication in regard to high spectral efficiency, spectral density, BER and less Peak to Average Power Ratio (PAPR).

Generalized Trapezoidal Companding Technique for PAPR Reduction in OFDM Systems

2018 ◽  
Vol 0 (0) ◽  
Author(s):  
Saruti Gupta ◽  
Ashish Goel
Keyword(s):  
Bit Error Rate ◽  
Orthogonal Frequency Division Multiplexing ◽  
Average Power ◽  
Frequency Division ◽  
Performance Parameters ◽  
Ofdm Systems ◽  
Ofdm System ◽  
Ofdm Signal ◽  
Specific Degree ◽  
Ofdm Signals

Abstract The main drawback in the performance of the Orthogonal Frequency Division Multiplexing (OFDM) system is the higher Peak-to-Average Power Ratio (PAPR) of the OFDM signals at the transmitter side. Companding is a well-known technique useful for reducing PAPR in the OFDM signal. This paper proposes a new nonlinear companding scheme that transforms the magnitude of Rayleigh distributed OFDM signal of specific degree into trapezoidal distribution. Additional design parameter is used in the proposed companding scheme to make the companding function more flexible. In the designed OFDM system the companding function has more degree of freedom which improves the PAPR and bit error rate (BER) parameters of the designed system. It has been demonstrated that the designed companding scheme provides more flexibility to accomplish an optimum trade-off between the performance parameters PAPR and BER of the designed OFDM system.

scholarly journals Palm Date Leaf Clipping: A New Method to Reduce PAPR in OFDM Systems

Information ◽  
2020 ◽  
Vol 11 (4) ◽  
pp. 190 ◽  
Author(s):  
Brahim Bakkas ◽  
Reda Benkhouya ◽  
Idriss Chana ◽  
Hussain Ben-Azza
Keyword(s):  
Communication Systems ◽  
Orthogonal Frequency Division Multiplexing ◽  
High Speed ◽  
Average Power ◽  
Papr Reduction ◽  
Frequency Division ◽  
Ofdm Systems ◽  
Leaf Clipping ◽  
Hyperbolic Cosine ◽  
Transmitted Signal

Orthogonal frequency division multiplexing (OFDM) is the key technology used in high-speed communication systems. One of the major drawbacks of OFDM systems is the high peak-to-average power ratio (PAPR) of the transmitted signal. The transmitted signal with a high PAPR requires a very large linear range of the Power Amplifier (PA) on the transmitter side. In this paper, we propose and study a new clipping method named Palm Clipping (Palm date leaf) based on hyperbolic cosine. To evaluate and analyze its performance in terms of the PAPR and Bit Error Rate (BER), we performed some computer simulations by varying the Clipping Ratio (CR) and modulation schemes. The obtained results show that it is possible to achieve a gain of between 7 and 9 dB in terms of PAPR reduction depending on the type of modulation. In addition, comparison with several techniques in terms of PAPR and BER shows that our method is a strong alternative that can be adopted as a PAPR reduction technique for OFDM-based communication systems.

scholarly journals Clipping Noise Compensation with Neural Networks in OFDM Systems

Signals ◽  
2020 ◽  
Vol 1 (1) ◽  
pp. 100-109
Author(s):  
Tzu-Hsien Sang ◽  
You-Cheng Xu
Keyword(s):  
Neural Network ◽  
Orthogonal Frequency Division Multiplexing ◽  
Frequency Division ◽  
Ofdm Systems ◽  
Inverse Discrete Fourier Transform ◽  
Noise Compensation ◽  
The Neural Network ◽  
Frequency Domains ◽  
Iterative Procedures ◽  
Ofdm Signals

The application of deep learning (DL) to solve physical layer issues has emerged as a prominent topic. In this paper, the mitigation of clipping effects for orthogonal frequency division multiplexing (OFDM) systems with the help of a Neural Network (NN) is investigated. Unlike conventional clipping recovery algorithms, which involve costly iterative procedures, the DL-based method learns to directly reconstruct the clipped part of the signal while the unclipped part is protected. Furthermore, an interpretation of the learned weight matrices of the neural network is presented. It is observed that parts of the network, in effect, implement transformations very similar to the (Inverse) Discrete Fourier Transform (DFT/IDFT) to provide information in both the time and frequency domains. The simulation results show that the proposed method outperforms existing algorithms for recovering clipped OFDM signals in terms of both mean square error (MSE) and Bit Error Rate (BER).

scholarly journals NOMA for Multinumerology OFDM Systems

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Ayman T. Abusabah ◽  
Huseyin Arslan
Keyword(s):  
Orthogonal Frequency Division Multiplexing ◽  
Multiple Access ◽  
Frequency Division ◽  
Ofdm Systems ◽  
Superposition Coding ◽  
Promising Technique ◽  
Successive Interference Cancelation ◽  
Power Domain ◽  
Multiple Access Schemes ◽  
Spectrally Efficient

Nonorthogonal multiple access (NOMA) is a promising technique which outperforms the traditional multiple access schemes in many aspects. It uses superposition coding (SC) to share the available resources among the users and adopts successive interference cancelation (SIC) for multiuser detection (MUD). Detection is performed in power domain where fairness can be supported through appropriate power allocation. Since power domain NOMA utilizes SC at the transmitter and SIC at the receiver, users cannot achieve equal rates and experience higher interference. In this paper, a novel NOMA scheme is proposed for multinumerology orthogonal frequency division multiplexing system, that is, different subcarrier spacings. The scheme uses the nature of mixed numerology systems to reduce the constraints associated with the MUD operation. This scheme not only enhances the fairness among the users but improves the bit error rate performance as well. Although the proposed scheme is less spectrally efficient than conventional NOMA schemes, it is still more spectrally efficient than orthogonal multiple access schemes.

A Modified DFT-Based Channel Estimator Using Dual-Tree Complex Wavelet Denoising for OFDM Systems with Null Carriers

2014 ◽  
Vol 668-669 ◽  
pp. 1215-1218
Author(s):  
Wei Cai Liu ◽  
Yuan An Liu ◽  
Kai Ming Liu ◽  
Yu Meng Guo
Keyword(s):  
Orthogonal Frequency Division Multiplexing ◽  
Additive White Gaussian Noise ◽  
Wavelet Denoising ◽  
Frequency Division ◽  
Ofdm Systems ◽  
Denoising Method ◽  
Performance Simulation ◽  
Channel Estimator ◽  
Suppression Method ◽  
Complex Wavelet

In this paper, we present a modified discrete Fourier transform (DFT)-based channel estimator for orthogonal frequency-division multiplexing (OFDM) systems with null carriers. Due to the channel leakage, the conventional DFT-based estimator has the problem of error floor. In order to suppress the leakage, we adopt the optimal leakage suppression method. Moreover, a novel denoising method based on dual-tree complex wavelet is proposed to further improve the performance. Simulation results show that the proposed channel estimator can effectively overcome the performance degradation caused by the leakage and additive-white gaussian noise (AWGN).

scholarly journals Analytical Investigation on Papr Reduction in OFDM Systems Using Golay Codes

2014 ◽  
Vol 65 (5) ◽  
pp. 289-293 ◽  
Author(s):  
Sabhyata Uppal ◽  
Sanjay Sharma ◽  
Hardeep Singh
Keyword(s):  
Orthogonal Frequency Division Multiplexing ◽  
Average Power ◽  
Analytical Investigation ◽  
Frequency Division Multiplexing ◽  
Power Ratio ◽  
Frequency Division ◽  
Ofdm Systems ◽  
Common Technique ◽  
Golay Codes ◽  
Modulation Code

Abstract Orthogonal frequency division multiplexing (OFDM) is a common technique in multi carrier communications. One of the major issues in developing OFDM is the high peak to average power ratio (PAPR). Golay sequences have been introduced to construct 16-QAM and 256-QAM (quadrature amplitude modulation) code for the orthogonal frequency division multiplexing (OFDM), reducing the peak-to-average power ratio. In this paper we have considered the use of coding to reduce the peakto- average power ratio (PAPR) for orthogonal frequency division multiplexing (OFDM) systems. By using QPSK Golay sequences, 16 and 256 QAM sequences with low PAPR are generated

Optimization and Simulation of OFDM System Based on Orthogonal Wavelet

2014 ◽  
Vol 548-549 ◽  
pp. 1221-1226
Author(s):  
Zeng You Sun ◽  
Fan Ming Zeng
Keyword(s):  
Fourier Transform ◽  
Discrete Fourier Transform ◽  
Orthogonal Frequency Division Multiplexing ◽  
Modulation Method ◽  
Frequency Division Multiplexing ◽  
Frequency Division ◽  
Ofdm Systems ◽  
Ofdm System ◽  
Orthogonal Wavelet ◽  
Optimization And Simulation

In order to reduce the Orthogonal Frequency division Multiplexing (OFDM) Inter-Carrier Interference (ICI), Put forward a kind of modulation method that based on the orthogonal frequency division multiplexing of orthogonal wavelet, Using orthogonal wavelet instead of discrete Fourier transform, optimize the design for OFDM systems, on the premise of without protection interval to reduce the system interference, using MATLAB to simulate the OFDM system, results show that the optimization of the OFDM can reduce the power of the ICI and Inter-symbol Interference (ISI) and improve the comprehensive anti-jamming of the OFDM system.

Sign in / Sign up

Export Citation Format

Share Document