scholarly journals SLM Technique to Reduce PAPR and Improve BER in OFDM Systems

2021 ◽  
Vol 9 (VI) ◽  
pp. 5138-5143
Author(s):  
N. Sai Santhosh
Keyword(s):  
Bit Error Rate ◽  
Error Rate ◽  
Orthogonal Frequency Division Multiplexing ◽  
Average Power ◽  
Rate Distortion ◽  
Estimation Accuracy ◽  
Frequency Division Multiplexing ◽  
Frequency Division ◽  
Ofdm Systems ◽  
Time Frequency

Through the combined use of multiple input, multiple output, and orthogonal frequency division multiplexing technologies, mankind has achieved a huge leap in the data rate of gigabit per second with the birth of 5G wireless technology. With frequency selective fading, multiple (OFDM MIMO) is possible. One of its most important performance concerns is PAPR (Peak-to-Average Power Ratio), which renders OFDM particularly vulnerable to harmonic distortion, reducing channel estimation accuracy and resulting in a lower bit error rate (BER). We propose a selective codeword shift mapping method for the MIMO-OFDM system (SCS-SLM). It lowers the PAPR and causes the power amplifier to operate in the non-linear area, resulting in intermodulation between sub-carriers, signal constellation, bit error rate distortion, as well as enhanced system performance. Furthermore, employing space-time-frequency block code (STFBC OFDM) orthogonal frequency division multiplexing might improve BER performance. This paper mentions a useful strategy for minimizing the PAPR, which is Selective Mapping. In addition, the bit error rate performance and, as a result, the process complexity for this system is discussed. In addition to the above-mentioned analysis, a thorough analysis of the mutual independence of the alternative OFDM signals generated using this technique is also discussed. Furthermore, this new approach has the important benefit of removing the extra bits on the side of the transmitted OFDM signal.

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.

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 APR Reduction Technique based on OFDM Pilot Filter Bank Limiting for Satellite Mobile Communications

2018 ◽  
Vol 246 ◽  
pp. 03002
Author(s):  
Tianfang Dai
Keyword(s):  
Mobile Communications ◽  
Bit Error Rate ◽  
Error Rate ◽  
Orthogonal Frequency Division Multiplexing ◽  
Filter Bank ◽  
Hardware Implementation ◽  
Reduction Technique ◽  
Papr Reduction ◽  
Frequency Division Multiplexing ◽  
Frequency Division

Combined with OFDM (Orthogonal Frequency Division Multiplexing), satellite mobile communications will effectively achieve on-demand communication in areas with an ultra-low density of users. With OFDM multiple access optimization, the bandwidth utilization efficiency can be increased by 5 to 10 times. However, satellites are power-constrained systems, so higher PAPR requires greater power backoff, resulting in a decline in satellite transmission capacity. To use OFDM technology in satellites, there are problems such as reduced transmission capacity resulted from high PAPR, complication of lowering PAPR, and difficulty in hardware implementation. In order to deal with the problem of high bit error rate and hardware implementation difficulties in PAPR reduction technique of non-orthogonal frequency division multiplexing, this paper proposes a limiting PAPR reduction technique with OFDM pilot filter banks for satellite mobile communications. Firstly, the applicability of OFDM in satellite mobile communications is analyzed, and the influence of high PAPR on satellite power utilization and the influence of frequency shift sensitivity on inter-satellite communication interference are obtained. Then design the PAPR reduction technique based on the pilot filter bank. By setting the tunable filter bank to the pilot, the sideband power suppression in the OFDM frequency domain is realized, and the PAPR of the OFDM signal is reduced. Finally, the experimental results show that the PAPR performance is improved by 3dB without reducing the bit error rate.

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

scholarly journals Research of the Influence of the Quadrature Components Mismatch on the Noise Immunity of OFDM and UFMC Signals

2021 ◽  
Vol 24 (1) ◽  
pp. 71
Author(s):  
A. Yu. Belousov ◽  
V. V. Khvorenkov
Keyword(s):  
Bit Error Rate ◽  
Error Rate ◽  
Orthogonal Frequency Division Multiplexing ◽  
Noise Immunity ◽  
Frequency Division Multiplexing ◽  
Frequency Division ◽  
Error Vector Magnitude ◽  
Error Vector ◽  
Vector Magnitude

Метод непосредственной модуляции с использованием комплексных сигналов применяется при реализации сигнальных трактов передатчиков в базовых станциях систем сотовой связи. В процессе модуляции возникают рассогласования коэффициента усиления и фазы квадратурных составляющих сигнала. Рассогласование ухудшает модуль вектора ошибки (Error Vector Magnitude, EVM) в приемнике, что, в свою очередь, приводит к повышению частоты появления ошибочных битов (Bit Error Rate, BER). Качество принимаемого сигнала выражается в частоте появления битовых ошибок. Рассогласование амплитуды и фазы квадратурных составляющих является одним из важнейших факторов, вносящих наибольший вклад в амплитуду вектора ошибки, который необходимо исследовать.В статье приведено исследование влияния рассогласования квадратурных составляющих сигналов технологий OFDM (Orthogonal frequency-division multiplexing) и UFMC (universal filtered multi-carrier). Разработана модель передатчика, канала связи и приемника для сигналов OFDM и UFMC. Модель построена в програм­мной среде MatLab при помощи языка MatLab и представляет собой программную модель m-script.В ходе работы путем исследования имитационной модели изучена зависимость помехоустойчивости технологий путем изменения параметров канала связи, таких как амплитудное и фазовое рассогласование квадратурных составляющих сигнала, а также отношение сигнал/шум. Проведен сравнительный анализ таких параметров сигналов, как занимаемая полоса частот, пик-фактор, частота появления битов с ошибкой. По результатам исследования получены графики зависимости вероятности ошибки и пик-фактора сигнала от рассогласования квадратурных составляющих для двух технологий – OFDM и UFMC. Проведенное исследование позволяет выделить преимущества технологии UFMC, которые выражаются в спектральной эффективности, помехоустойчивости и уровне пик-фактора сигнала.

scholarly journals An identification of the tolerable time-interleaved analog-to-digital converter timing mismatch level in high-speed orthogonal frequency division multiplexing systems

2022 ◽  
Vol 12 (2) ◽  
pp. 1667
Author(s):  
Vo Trung Dung Huynh ◽  
Linh Mai ◽  
Hung Ngoc Do ◽  
Minh Ngoc Truong Nguyen ◽  
Trung Kien Pham
Keyword(s):  
Bit Error Rate ◽  
Error Rate ◽  
Communication Systems ◽  
Orthogonal Frequency Division Multiplexing ◽  
High Speed ◽  
Performance Degradation ◽  
Frequency Division Multiplexing ◽  
Frequency Division ◽  
Analog To Digital ◽  
Time Interleaved

<span>High-speed Terahertz communication systems has recently employed orthogonal frequency division multiplexing approach as it provides high spectral efficiency and avoids inter-symbol interference caused by dispersive channels. Such high-speed systems require extremely high-sampling <br /> time-interleaved analog-to-digital converters at the receiver. However, timing mismatch of time-interleaved analog-to-digital converters significantly causes system performance degradation. In this paper, to avoid such performance degradation induced by timing mismatch, we theoretically determine maximum tolerable mismatch levels for orthogonal frequency division multiplexing communication systems. To obtain these levels, we first propose an analytical method to derive the bit error rate formula for quadrature and pulse amplitude modulations in Rayleigh fading channels, assuming binary reflected gray code (BRGC) mapping. Further, from the derived bit error rate (BER) expressions, we reveal a threshold of timing mismatch level for which error floors produced by the mismatch will be smaller than a given BER. Simulation results demonstrate that if we preserve mismatch level smaller than 25% of this obtained threshold, the BER performance degradation is smaller than 0.5 dB as compared to the case without timing mismatch.</span>

scholarly journals Analysis of the PAPR Behavior of the OFDM Passband Signal

2019 ◽  
Author(s):  
Frank Andrés Eras ◽  
Italo Alexander Carreño ◽  
Thomás Borja ◽  
Diego Javier Reinoso ◽  
Luis Urquiza-Aguiar ◽  
...  
Keyword(s):  
Bit Error Rate ◽  
Communication Systems ◽  
Orthogonal Frequency Division Multiplexing ◽  
Average Power ◽  
Wireless Communication Systems ◽  
Frequency Division Multiplexing ◽  
Power Ratio ◽  
Frequency Division ◽  
Ofdm System ◽  
High Power Amplifier

Orthogonal Frequency Division Multiplexing (OFDM) is a technique widely used in today's wireless communication systems due to its ability to combat the effects of multi-path in the signal. However, one of the main limitations of the use of OFDM is its high Peak-to-Average Power Ratio (PAPR), which reduces the efficiency of the OFDM system. The effects of PAPR can produce both out-of-band and in-band radiation, which degrades the signal by increasing the bit error rate (BER), this occurs in both baseband and bandpass sginals. In this document the effect of the PAPR in a OFDM passband signal is analyzed considering the implementation of a High Power Amplifier (HPA) and the Simple Amplitude Predistortion-Orthogonal Pilot Sequences (OPS-SAP) scheme to reduce the PAPR.

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