scholarly journals An efficient technique for out-of-band power reduction for the eliminated CP-STC-shaped system for 5G requirements

2020 ◽  
Vol 10 (5) ◽  
pp. 5306
Author(s):  
Mohamed Yasin I. Afifi ◽  
Mohamed S. Elbakry ◽  
El-Sayed S. A. Soliman ◽  
A. A. Ammar
Keyword(s):  
Computational Complexity ◽  
Additive White Gaussian Noise ◽  
Average Power ◽  
Multipath Fading ◽  
Numerical Results ◽  
Cumulative Distribution ◽  
Ofdm System ◽  
Multipath Fading Channel ◽  
Main Technique ◽  
Power Radiation

The most dominant needs for the recent wireless mobile applications are higher bandwidth (BW) efficiency, higher energy efficiency higher quality of services (QOS). The main technique in 4G systems is OFDM but it suffers from some limitations such as large peak to average power ratio (PAPR), higher Out-of-Band (OOB) power radiation, and wasting bandwidth efficiency due to cyclic prefix (CP) extension. In his paper, these OFDM limitations will be reduced with low computational complexity compared to filter bank multicarriers (FBMC). The proposed scheme is based on symbol time compression (STC) for OFDM system. The proposed STC-Shaped system is achieved via interleaver-spreader and symbol shaper in the transmitter side in addition to equalization and combining processes in the receiver side. Comparative study between the proposed system and the conventional OFDM in case of additive white Gaussian noise (AWGN) and COST 207 typical multipath fading channel will be presented. The numerical results show that the proposed STC-Shaped scheme reduces OOB significantly. The proposed scheme improves BER in multipath Rayleigh fading although it is without CP. Thus, the proposed system is more robust against inter symbol interference (ISI) compared to conventional OFDM system. Also, the numerical results show that the PAPR of the proposed system is decreased significantly and also, it is derived theoretically. Also, the proposed scheme overcomes CP extension, and hence increases the bandwidth (BW) efficiency. Finally, the computational complexity for the proposed scheme is derived and it has very low complexity compared to FBMC. The system performance measurments has been fulfilled using cumulative distribution function (CDF), power spectral density (PSD) and bit error rate (BER).

scholarly journals BCH codes for 5G wireless communication systems over multipath fading channel

2020 ◽  
Vol 17 (1) ◽  
pp. 310
Author(s):  
Ghasan Ali Hussain ◽  
Lukman Audah
Keyword(s):  
Channel Coding ◽  
Fading Channel ◽  
Communication Systems ◽  
Average Power ◽  
Multipath Fading ◽  
Ofdm System ◽  
Trade Off ◽  
Multipath Fading Channel ◽  
Trade Offs ◽  
Ber Performance

<span>Due to its large peak to average power ratio (PAPR) and high out of band emission (OOBE), OFDM doesn't meet the requirements of 5G services. Additionally, it supports only one type of waveform parameters in entire bandwidth. In contrast, f-OFDM is dividing the system's bandwidth into a number of subbands to support several waveform parameters based on various service scenarios. So, Filtered-OFDM (f-OFDM) is considered as a modern enabler of the flexible waveform to overcome the OFDM drawbacks while remaining its advantages as well as, to encounter the new challenges that faced 5G. Nonetheless, there is a trade-off among OOBE, PAPR and SNR performance. Meanwhile, channel coding technology is one of the most important issue in physical layer which is playing an essential role in order to achieve the reliability and latency. So, BCH code has been suggested in this paper for f-OFDM system to achieve the reliability of transmission information and thus improving BER performance over multipath fading channel. Whilst, BCH-LTE system is introduced as a baseline in this paper that using for comparison purpose with proposed system. Simulation results showed that the proposed BCH-f-OFDM system was significantly better than BCH-LTE system in terms of decreasing OOBE and achieving improving in BER performance. Although, PAPR levels was stilling high in proposed system due to the trade-off among OOBE, PAPR and SNR performance. However, the proposed system is considered a promising candidate to meet the requirements of 5G services because of its ability to solve two important issues in between three trade-offs'.</span>

PAPR Performance Improvement in OFDM System Using DCT Based on Adjacent Symbol Grouping

2014 ◽  
Vol 550 ◽  
pp. 204-209
Author(s):  
K. Muralibabu ◽  
M. Sundhararajan
Keyword(s):  
Performance Improvement ◽  
Fading Channel ◽  
Orthogonal Frequency Division Multiplexing ◽  
Average Power ◽  
Multipath Fading ◽  
Frequency Division ◽  
Ofdm System ◽  
Multipath Fading Channel ◽  
A New Technique ◽  
Papr Performance

In wireless communication, Orthogonal Frequency Division Multiplexing (OFDM) is a promising scheme against the multipath fading channel .However, due multi-carrier transmission , OFDM system has a major draw back of Peak-to-Average Power Ratio (PAPR) problem that affect the efficiency of HPA in the transmitter side. In the proposed scheme, a new technique is discussed for reducing PAPR in the OFDM system by using Discrete Cosine Transform (DCT) and adjacent sub carriers grouping with companding technique.A computer simulation is used to evaluate the performance of the proposed PAPR scheme.

scholarly journals A Novel Signal Detection Algorithm for Underwater MIMO-OFDM Systems Based on Generalized MMSE

2019 ◽  
Vol 2019 ◽  
pp. 1-10
Author(s):  
Gaoli Zhao ◽  
Jianping Wang ◽  
Wei Chen ◽  
Junping Song
Keyword(s):  
Computational Complexity ◽  
Signal Detection ◽  
Mean Square Error ◽  
High Performance ◽  
Minimum Mean Square Error ◽  
Multipath Fading ◽  
Detection Algorithm ◽  
Mean Square ◽  
Ofdm System ◽  
Mimo Ofdm

The MIMO-OFDM system fully exploits the advantages of MIMO and OFDM, effectively resisting the channel multipath fading and inter-symbol interference while increasing the data transmission rate. Studies show that it is the principal technical mean for building underwater acoustic networks (UANs) of high performance. As the core, a signal detection algorithm determines the performance and complexity of the MIMO-OFDM system. However, low computational complexity and high performance cannot be achieved simultaneously, especially for UANs with a narrow bandwidth and limited data rate. This paper presents a novel signal detection algorithm based on generalized MMSE. First, we propose a model for the underwater MIMO-OFDM system. Second, we design a signal coding method based on STBC (space-time block coding). Third, we realize the detection algorithm namely GMMSE (generalized minimum mean square error). Finally, we perform a comparison of the algorithm with ZF (Zero Forcing), MMSE (minimum mean square error), and ML (Maximum Likelihood) in terms of the BER (bit error rate) and the CC (computational complexity). The simulation results show that the BER of GMMSE is the lowest one and the CC close to that of ZF, which achieves a tradeoff between the complexity and performance. This work provides essential theoretical and technical support for implementing UANs of high performance.

Reduction of Peak-to-Average Power Ratio in Orthogonal Frequency Division Multiplexing System Using Haar Wavelet Approach

2019 ◽  
Vol 16 (2) ◽  
pp. 484-488
Author(s):  
K. Rajasekhar ◽  
Prabhakara B. Rao
Keyword(s):  
Orthogonal Frequency Division Multiplexing ◽  
Average Power ◽  
Haar Wavelet ◽  
Distribution Functions ◽  
Cumulative Distribution ◽  
Frequency Division Multiplexing ◽  
Power Ratio ◽  
Frequency Division ◽  
Ofdm System ◽  
Spectral Null

In Orthogonal Frequency Division Multiplexing (OFDM) based systems, with the increasing demand for data rate and reliability in Wireless communications and devices, several issues become very important like bandwidth efficiency, quality of service and radio coverage. However, OFDM is very sensitive to nonlinear effects due to the high peak-to-average power ratio (PAPR) owned by the transmitted signals and does not show robustness to spectral null channels. This paper proposes a novel BPSK OFDM system based on Haar wavelet transformation. The PAPR reduced by 10 log10 2 ≈ 3 dB at most, compared with the conventional OFDM system and shows robustness to spectral null channels, improving BER performance 3 dB at most. Finally, theoretical and simulated results of the Cumulative Distribution Functions (CDFs) of both Conventional and Proposed OFDM are compared to show that the Proposed OFDM has better performance than the Conventional OFDM.

Improved Clipping Technique for PAPR Reduction in OFDM

2014 ◽  
Vol 548-549 ◽  
pp. 1420-1423
Author(s):  
M.R. Anjum ◽  
M.A. Shaheen ◽  
Farhan Manzoor ◽  
Mussa A. Dida
Keyword(s):  
Orthogonal Frequency Division Multiplexing ◽  
High Speed ◽  
Average Power ◽  
Multipath Fading ◽  
Papr Reduction ◽  
Major Drawback ◽  
Multipath Fading Channel ◽  
Peak Magnitude ◽  
Ofdm Signal ◽  
Clipping Technique

Multicarrier modulation technique also known as Orthogonal Frequency Division Multiplexing (OFDM) is considered to be the most rapidly growing technique for 4th Generation wireless communication system. Due to its high speed data rate and its ability of multipath fading channel robustness. OFDM becomes an attractive technique and it is widely adopted in many wireless communications system. OFDM signal carries its major drawback of high Peak to Average Power Ratio (PAPR) problem. Out of band radiation and in band distortion produced due to its high PAPR. Mobile phone communication suffer severe drawback during its amplification. When OFDM employed a non linear Power Amplifier (PA), it produces the fluctuation in amplitude of OFDM signal. This paper discusses the method to overcome PAPR in terms of its performance by using improved clipping technique for PAPR reduction. This method is easy to implement and reduces the amount of PAPR by clipping the peak of the maximum power signal. We present an improved method for PARR reduction for reducing peak magnitude of OFDM signal. This scheme simultaneously minimizes the peak magnitude of PAPR in OFDM signal.

scholarly journals CE-OFDM-CDMA Phase Modulation for 5G System

2021 ◽  
Vol 6 (4) ◽  
pp. 1100-1114
Author(s):  
Jamal Mestoui ◽  
Mohammed El Ghzaoui ◽  
Serghini Elaage ◽  
Abdelmounim Hmamou ◽  
Jaouad Foshi
Keyword(s):  
Phase Modulation ◽  
Orthogonal Frequency Division Multiplexing ◽  
Additive White Gaussian Noise ◽  
Minimum Mean Square Error ◽  
Average Power ◽  
Multipath Fading ◽  
Modulation Scheme ◽  
Time Frequency ◽  
High Spectral Efficiency ◽  
Code Division Multiple

In the present work, we propose a novel modulation scheme for 5G wireless communication system. Our contribution is to combine PM-OFDM (Phase Modulation Orthogonal Frequency Division Multiplexing) and CDMA (Code Division Multiple Access) to exploit their distinctive advantages. On the one hand, PM-OFDM is an effective technique to combat multipath fading effects. On the other hand, CDMA can serve multiple users who are using the same resources of time/frequency. The aim is to make a combination of PM-OFDM and CDMA techniques. In this paper, the OFDM-CDMA scheme and its PAPR (Peak-to-Average Power Ratio) statistics are reviewed. In this paper, the proposed scheme PM-OFDM-CDMA is described and its performances in terms of PAPR, power spectral density, and BER (Bit Error Rate) are analyzed. Moreover, MMSE (Minimum Mean Square Error) equalizer is used to avoid multipath and noise effects simultaneously. The simulation through AWGN (Additive white Gaussian noise) and Rayleigh channels is performed using MATLAB. From the simulation results, we observed that PM-OFDM-CDMA is an efficient technique in terms of energy consumption (PAPR = 0dB). Besides, CE-OFDM-CDMA offers high spectral efficiency with low BER due to its low PAPR. In CE-OFDM-CDMA method, the shape of the spectrum varies according to the value of the modulation index h. The band occupied by the spectrum increases with the value of h. Therefore, CE-OFDM-CDMA could be considered as a suitable technique for 5G applications.

scholarly journals BER PERFORMANCE ANALYSIS OF 4QAM/OFDM OVER DIFFERENT SCENARIOS OF LAPLACE FADING CHANNEL.

2021 ◽  
Vol 25 (Special) ◽  
pp. 1-26-1-33
Author(s):  
Hassan F. Mohammed ◽  
◽  
Ghanim A. Al-Rubaye ◽  
Keyword(s):  
Fading Channels ◽  
Fading Channel ◽  
Orthogonal Frequency Division Multiplexing ◽  
High Speed ◽  
Additive White Gaussian Noise ◽  
Multipath Fading ◽  
Local Area ◽  
Ofdm System ◽  
Multicarrier Transmission ◽  
Simulation Results

Multicarrier transmission, also known as (OFDM) Orthogonal Frequency Division multiplexing, in wireless communications, it has been proven to be an essential technique for countering multipath fading. It has been used successfully for HF radio applications and has been selected as the interface for digital audio transmission, digital terrestrial TV broadcasting, and high-speed wireless local area networks in Europe. In this paper, we suggested a new design for modeling multipath fading channels, such as the Laplace fading channel, in order to discover new simulation results and effects. Furthermore, the variance of the Laplace fading channel has been computed and the new Bit Error Rate (BER) derivation is established, and the performance of (M-QAM), M-ary Quadrature Amplitude Modulation (with M=4 over OFDM system under Laplace fading channels in Additive White Gaussian Noise (AWGN) is discussed and compared to the conventional M-QAM/OFDM system Rayleigh fading channel in AWGN. All the simulation results are examined using the optimum signal detection based on the Euclidean distance and evaluated using Monte-Carlo simulation.

scholarly journals Partial PIC-MRC Receiver Design for Single Carrier Block Transmission System over Multipath Fading Channels

2012 ◽  
Vol 2012 ◽  
pp. 1-9
Author(s):  
Juinn-Horng Deng ◽  
Sheng-Yang Huang
Keyword(s):  
Fading Channels ◽  
Interference Cancellation ◽  
Fading Channel ◽  
Communication Systems ◽  
Average Power ◽  
Multipath Fading ◽  
Low Complexity ◽  
Multipath Fading Channel ◽  
Block Transmission ◽  
Single Carrier

Single carrier block transmission (SCBT) system has become one of the most popular modulation systems due to its low peak-to-average power ratio (PAPR), and it is gradually considered to be used for uplink wireless communication systems. In this paper, a low complexity partial parallel interference cancellation (PIC) with maximum ratio combining (MRC) technology is proposed to use for receiver to combat the intersymbol interference (ISI) problem over multipath fading channel. With the aid of MRC scheme, the proposed partial PIC technique can effectively perform the interference cancellation and acquire the benefit of time diversity gain. Finally, the proposed system can be extended to use for multiple antenna systems to provide excellent performance. Simulation results reveal that the proposed low complexity partial PIC-MRC SIMO system can provide robust performance and outperform the conventional PIC and the iterative frequency domain decision feedback equalizer (FD-DFE) systems over multipath fading channel environment.

Understanding Peak Average Power Ratio in VFFT-OFDM Systems

2015 ◽  
Vol 776 ◽  
pp. 419-424 ◽  
Author(s):  
N.M.A.E.D. Wirastuti
Keyword(s):  
Distribution Function ◽  
Cumulative Distribution Function ◽  
Statistical Approach ◽  
Average Power ◽  
Cumulative Distribution ◽  
Power Ratio ◽  
Ofdm Systems ◽  
Ofdm System ◽  
Complementary Cumulative Distribution Function ◽  
Simulation Results

This paper describes an impairment commonly encountered in an OFDM system that must be considered in the design that is peak average power ratio (PAPR). In these studies, a statistical approach to analysing PAPR is suggested. The PAPR statistics of OFDM and VFFT-OFDM are studied by simulation of the statistical distribution of the quantity that is the Complementary Cumulative Distribution Function (CCDF) of the PAPR. The simulation results show that the simulated CCDF of PAPR, the 1% PAPR of OFDM is about 11.40 dB, whereas for VFFT-OFDM this rises to less than 3% of the time. Simulations show that by employing VFFT in OFDM system results in a 0.55 dB deterioration in the PAPR 1% of time.

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