scholarly journals Bit error rate analysis of different digital modulation schemes in orthogonal frequency division multiplexing systems

2018 ◽  
Vol 37 (3) ◽  
pp. 727 ◽  
Author(s):  
S. O. Ajose ◽  
A. L. Imoize ◽  
O. M. Obiukwu
Keyword(s):  
Bit Error Rate ◽  
Error Rate ◽  
Orthogonal Frequency Division Multiplexing ◽  
Frequency Division Multiplexing ◽  
Frequency Division ◽  
Digital Modulation ◽  
Rate Analysis ◽  
Modulation Schemes ◽  
Multiplexing Systems

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 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 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.

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