scholarly journals Evaluaciónde OPS para la Reducción de la PAPR en un SistemaOFDM conCanal Multitrayecto

2020 ◽  
Vol 44 (2) ◽  
pp. 35-42
Author(s):  
María Peñaherrera ◽  
Diego Reinoso
Keyword(s):  
Bit Error Rate ◽  
Orthogonal Frequency Division Multiplexing ◽  
Density Ratio ◽  
Average Power ◽  
Noise Power ◽  
Power Ratio ◽  
Frequency Division ◽  
Complementary Distribution ◽  
Noise Power Spectral Density ◽  
Power Spectral

OFDM (Orthogonal Frequency Division Multiplexing) es una tecnología de comunicacióninalámbrica que tiene ventajas como alta eficiencia espectral, alta tasa de transmisión y es robusta a la propagación por mulitrayecto. Sin embargo, su principal desventaja es que tienealta PAPR (Peak-to-Average Power Ratio).Este artículo presenta la evaluaciónde la técnica OPS (Orthogonal Pilot Sequence) para la reducción de la PAPR en un sistema OFDM con canal multitrayecto. Para la evaluación se consideran dos tipos de canalesmultitrayecto selectivos en frecuencia, con y sin línea de vista. Se evalúa la técnica OPS obteniendola gráfica del BER (Bit Error Rate)vs Eb/No (energy per bit to noise power spectral density ratio) y la gráfica de la CCDF (Cumulative Complementary Distribution Function) para distintos parámetros. Losresultados muestran una reducción de la PAPR cuando se utiliza la técnica OPS y una mejora en el BER.

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.

scholarly journals Spectral Properties of Clipping Noise

Mathematics ◽  
2021 ◽  
Vol 9 (20) ◽  
pp. 2592
Author(s):  
Alexander Frömming ◽  
Lars Häring ◽  
Andreas Czylwik
Keyword(s):  
Spectral Density ◽  
Power Spectral Density ◽  
Orthogonal Frequency Division Multiplexing ◽  
Average Power ◽  
Simple Expression ◽  
Damping Factor ◽  
Noise Power ◽  
Power Ratio ◽  
Transmission Bandwidth ◽  
Power Spectral

One serious disadvantage of any multicarrier-modulation technique such as orthogonal frequency division multiplexing (OFDM) is its high peak-to-average-power ratio (PAPR) which might lead to signal clipping in several scenarios. To maximize the transmit data rate, it is important to take this non-linear distortion into account. The most common approach is based on the Bussgang theorem, which splits the distortion in a correlated part, represented by a linear damping factor, and uncorrelated additive noise. However, there are two aspects that are not correctly considered by the Bussgang theorem. Firstly, clipping noise shows a frequency-dependent power spectrum which depends on the clipping probability. Secondly, some of the clipping noise power is located outside of the transmission bandwidth, so that it does not influence the transmission quality. In this work, the Bussgang theorem is reviewed in detail and the exact power spectral density of the uncorrelated clipping noise is approximated to determine the signal-to-noise power ratio on every subcarrier separately. Although it is shown that the frequency dependence within the transmission bandwidth is relatively small, at least 36% of the uncorrelated noise power, depending on the clipping level, lays outside of the transmission band. Monte Carlo simulations validate that a simple expression for the power spectral density allows to calculate the symbol error probability of an OFDM transmission system that suffers from clipping. Furthermore, the newly found result can be used to optimize bit allocation tables in bit loading algorithms or to calculate the channel capacity.

scholarly journals Blind Algorithm Development for Peak to Average Power Ratio Reduction in OFDM Systems under Frequency Selective Channels

2019 ◽  
Vol 38 (2) ◽  
pp. 192-130
Author(s):  
Godwin M. Gadiel ◽  
Kamwe Ibwe ◽  
M.M Kisaka
Keyword(s):  
Orthogonal Frequency Division Multiplexing ◽  
Average Power ◽  
Cumulative Distribution ◽  
Noise Power ◽  
Power Ratio ◽  
Signal Power ◽  
Frequency Division ◽  
Ofdm Systems ◽  
Frequency Selective ◽  
Frequency Selective Channels

One major drawback of orthogonal frequency division multiplexing (OFDM) system is peak to average power ratio (PAPR). This effect causes high power amplifier (HPA) to introduce intermodulation and out of band radiation as the signal goes through, thus degrades the performance of OFDM systems. This paper proposes blind algorithms which takes advantage of signal transformation technique and signal distortion technique. Simulation results show that at complementary cumulative distribution function (CCDF) level of 10-3 , the proposed algorithm achieved 3.2 dB PAPR improvement compared to discrete Fourier transform with interleaved frequency division multiple access (DFT-IFDMA) based algorithm. The bit error rate (BER) performance has degraded by 2 dB compared to the original OFDM signal with no distortion under frequency selective channel (FCS) at BER of 10-4 . These presented results, mark this algorithm as a better candidate for PAPR reduction algorithm in long term evolution (LTE) network. Under AWGN channels, the proposed algorithm performs better both in low and high signal power values. Under frequency selective channels, the existing and proposed algorithm converges after 10 dB of signal to noise power values. The low BER transmissions at low signal power values signify energy efficiency, ideal for portable wireless devices with limited battery power.

scholarly journals Advantages of Spectrally Efficient Frequency Division Multiplexing Over Orthogonal Frequency Division Multiplexing

2020 ◽  
Vol 9 (8) ◽  
pp. 238-244
Keyword(s):  
Orthogonal Frequency Division Multiplexing ◽  
Average Power ◽  
Frequency Division Multiplexing ◽  
Power Ratio ◽  
Frequency Division ◽  
Sphere Decoder ◽  
Symbol Rate ◽  
Transmission Length ◽  
Spectrally Efficient ◽  
The Impact

An analysis on Spectrally Efficient Frequency Division Multiplexing (SEFDM) is contrast with Orthogonal Frequency Division Multiplexing (OFDM) considering the impact on Peak to Average Power Ratio (PAPR) and nonlinearities within fibre. With respect to OFDM the sub-carriers in SEFDM signals are compressed adjacent to each other at a rate of frequency lesser than the symbol rate. At the receiver end we have utilized the Sphere Decoder which is used to recover the data to remunerate the Interference created by the compressed signals (ICI) faced in the system. This research shows the advantages by using SEFDM and evaluates its achievement. PAPR. when compared with OFDM, while effects of non-linear fibres are considered. The use of various formats of modulation going from 4-QAM to 32-QAM, shows that the SEFDM signals have a noteworthy increment in the transmission length with respect to ordinary signals.

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.

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