PAPR Reduction Techniques

Risk is defined as the probability of a specific adverse event occurring within a specific period, while Quantitative risk assessment (QRA) is the development of a quantitative estimate of risk based on engineering evaluation and mathematical techniques by combining estimate of incident consequences and frequencies. In view of the increase in the use of railways as the mode of transportation for hazardous materials throughout the world, the associated risk analysis should be taken into concern. In this study, the failure frequency of the transportation of ammonia from the Petronas fertilizers Kedah (PFK) plant in Gurun (Northern part of Peninsular Malaysia), to the Chemical Company Malaysia (CCM) fertilizer's facilities in Port Klang (South-western part of Peninsular Malaysia) was evaluated by incorporating the human error assessment. The study highlighted the importance of human error contributions in the failure frequency analysis and its impact on the selected failure scenarios. Besides, it also shows that the application of the human error assessment and reduction technique (HEART), which is a useful human reliability analysis tool, should be used in parallel with the fuzzy arithmetic approach to reduce the uncertainties involved in the estimation of human error probabilities, and hence, to reduce the likelihood of incorrect risks estimates being assessed. The results suggested that the commonly applied approach in quantitative risk assessments, which only consider equipment failures in the failure frequency estimations, are clearly an underestimate of the potential causes of failures leading to hazardous material releases, and hence, the calculated risks based do not reflect the actual risks. © 2008 American Institute of Chemical Engineers Process Saf Prog, 2009

There are more than 150 pages of new material, covering
• cognitive radio (new Chapter 21);
• cooperative communications, relays, and ad hoc networks (new Chapter 22);
• video coding (new Chapter 23);
• 3GPP Long-Term Evolution (new Chapter 27);
• WiMAX (new Chapter 28).
There are furthermore significant extensions and additions on the following:
• MIMO (in Chapter 20), in particular a new section on multi-user MIMO (Section 20.3).
• IEEE 802.11n (high-throughput WiFi) in Section 29.3.
• Coding (bit-interleaved coded modulation) in Section 14.5.
• Introduction to information theory in Sections 14.1, 14.9, and Appendix 17.
• Channel models: updates of standardized channel models in Appendix 7.
• A number of minor modifications and reformulations, partly based on feedback from instructors
and readers of the book.

Multiple inputs multiple output orthogonal frequency division multiplexing (MIMO-OFDM) is an attractive transmission technique for high bit-rate communication systems. MIMO-OFDM has become a promising candidate for high performance 4G broadband wireless communications. One main disadvantage of OFDM is the high peak-to-average power ratio (PAPR) of the transmitter's output signal. Selected-Mapping (SLM) scheme which does not require the transmission of side information and can reduce the peak to average power ratio (PAPR) in turbo coded orthogonal frequency division multiplexing (OFDM) system is proposed. Simulation results show that the system can achieve significant reduction in PAPR and satisfactory bit error rate performance over AWGN channels. KEYWORDS Orthogonal Frequency Division Multiplexing (OFDM), peak-to-average-power-ratio (PAPR), Selective Mapping (SLM), Complementary Cummulative Distribution Function (CCDF), Bit Error Rate (BER).

High Peak to Average Power Ratio (PAPR) of the transmitted signal is a critical problem in multicarrier modulation systems (MCM) such as Orthogonal Frequency Division Multiplexing (OFDM), and Multi-Carrier Code Division Multiple Access (MC CDMA) systems, due to large number of subcarriers. High PAPR leads to reduced resolution, and battery life. It also deteriorates system performance. This paper focuses on review of different PAPR reduction techniques with attendant
technical issues as well as criteria for selection of PAPR reduction technique. To reduce PAPR the constraints are low power consumption, and low Bit Error Rate (BER). Spectral bandwidth is improved by better spectral characteristics, and low complexity/cost.

This paper proposes an advanced MIMO-OFDM reconfigurable architecture along with companding transform. The reconfigurable architecture uses switching algorithm between MIMO diversity and special multiplexing which allows selecting the MIMO configuration and improves the BER. The major drawback of orthogonal frequency division multiplexing (OFDM) system is peak to average power ratio (PAPR). Many techniques were developed to reduce PAPR. Considering all available PAPR reduction techniques, companding transform is attractive technique for its simplicity. This paper put forward the comparison of two techniques namely exponential companding and nonlinear companding. In this paper evaluation of performance is shown in terms of bit error rate and peak to average power ratio.

Several high-speed wireless systems use Orthogonal Frequency Division Multiplexing (OFDM) due to its advantages. 5G has adopted OFDM and is expected to be considered beyond 5G (B5G). Meanwhile, OFDM has a high Peak-to-Average Power Ratio (PAPR) problem. Hybridization between two PAPR reduction techniques gains the two techniques’ advantages. Hybrid precoding-companding techniques are attractive as they require small computational complexity to achieve high PAPR reduction gain. Many precoding-companding techniques were introduced to increasing the PAPR reduction gain. However, reducing Bit Error Rate (BER) and out-of-band (OOB) radiation are more significant than increasing PAPR reduction gain. This paper proposes a new precoding-companding technique to better reduce the BER and OOB radiation than previous precoding-companding techniques. Results showed that the proposed technique outperforms all previous precoding-companding techniques in BER enhancement and OOB radiation reduction. The proposed technique reduces the Error Vector Magnitude (EVM) by 15 dB compared with 10 dB for the best previous technique. Additionally, the proposed technique increases high power amplifier efficiency (HPA) by 11.4%, while the best previous technique increased HPA efficiency by 9.8%. Moreover, our proposal achieves PAPR reduction gain better than the most known powerful PAPR reduction technique with a 99% reduction in required computational complexity. View Full-Text

Mixed-numerology transmission is proposed to support a variety of communication scenarios with diverse requirements. However, as the orthogonal frequency division multiplex-ing (OFDM) remains as the basic waveform, the peak-to average power ratio (PAPR) problem is still cumbersome. In this paper, based on the iterative clipping and filtering (ICF) and optimization methods, we investigate the PAPR reduction in the mixed-numerology systems. We first illustrate that the direct extension of classical ICF brings about the accumulation of inter-numerology interference (INI) due to the repeated execution. By exploiting the clipping noise rather than the clipped signal, the noise-shaped ICF (NS-ICF) method is then proposed without increasing the INI. Next, we address the in-band distortion minimization problem subject to the PAPR constraint. By reformulation, the resulting model is separable in both the objective function and the constraints, and well suited for the alternating direction method of multipliers (ADMM) approach. The ADMM-based algorithms are then developed to split the original problem into several subproblems which can be easily solved with closed-form solutions. Furthermore, the applications of the proposed PAPR reduction methods combined with filtering and windowing techniques are also shown to be effective.

In this paper we suggest to use the ASTC (Algebraic Space Time Codes) as powerful coding technique for IEEE 802.11x OFDM standard combined with PAPR reduction scheme. ASTC with their very Algebraic-construction based on Quaternionic algebra, have a full rate, full diversity, non-vanishing constant minimum determinant for increasing spectral efficiency, uniform average transmitted energy per antenna and good shaping, readily lend themselves to high data rate situations. However, by their construction they require a nonselective flat fading channels belonging to narrow-band systems. In fact, such systems are not readily found in airs interfaces. In open air we have what are commonly called frequency-selective fading channels. As a matter of fact, it becomes extremely necessary to harness their power for wide-band systems.

The 3rd generation partnership project (3GPP) long term evolution (LTE) standard uses single carrier
frequency division multiple access (SC-FDMA) scheme for the uplink transmissions and orthogonal
frequency division multiplexing access (OFDMA) in downlink.

International Journal of Wireless & Mobile Networks (IJWMN), Vol.2, No.2, May 2010 ... Adaptation of ASTC in a Correlated Rayleigh ... Ahmed BANNOUR∗, Mohamed Lassaad AMMARI† and Ridha BOUALLEGUE‡ ∗ ‡ SUP'COM, 6'Tel Unit, Higher School of Communication of ...

The multifold increase in multimedia technology triggers an insatiable thirst for high data rates and increased demand for Orthogonal Frequency Division Multiplexing based wireless systems, a superior technology for the high-speed wireless communication systems. OFDM technique possesses multiple benefits superior to its predecessor, namely, its high capacity and resistance to multipath fading channels. Nonetheless, few hurdles remain yet unresolved in OFDM systems. The foremost issue stands out to be the high Peak to Average Power Ratio, which results in non-linearity in the High-Power Amplifiers and drives In-Band Distortion and Out-Of-Band Emission. Research plans are currently under development to standardize, given the economic 5G boom for market commercialization. The rise of superior waveform competitors possessing higher spectrum throughput, lower Peak to Average Power Ratio having a more straightforward system design than the celebrated OFDM. Potential candidates include numerous single carrier and multi-carrier waveforms. This paper undertakes an assessment, highlights the strengths and weaknesses of various 5G waveform candidates under the Key Performance Indicators, Simulation is carried out to study the PAPR reduction capabilities of these waveforms

LTE was proposed in 2004 Toronto conference to fulfill the requirement of achieving higher speed and lower packets latency in UMTS 3G systems. LTE which is abbreviated as long term evolution is an basically a transmission mode of providing the communication channel/communication link between the mobile portable device’s connected with each other to establish the connection between the two. LTE is composed of many new technologies compared with the previous generation of cellular systems. These new technologies are used to generate more efficiency with regards to spectrum and higher data rates as expected by designers. The currently agreed LTE architecture adopts a flat architecture, inheriting four functional elements named as Evolved Radio Access Network, User Equipment (UE) and hosts the physical layer (PHY), Medium Access Control (MAC), Radio Link Control (RLC), and Packet Data Control Protocol (PDCP) layers, Serving Gateway (SGW) and Mobility Management Entity. To do this work it has various numerous number of techniques through which it establish the link between the two. The technologies were named as OFDM, MIMO, and FDMA, SC-FDMA and so on. as it keep and maintains accuracy while providing the medium cascade to perform the task as it make use of TDD,FDD,QAM as multiplexing technologies.

In this paper, we investigate multi user chirp spread spectrum with noncoherent detection as a continuation of our work on coherent detection in [1]. We derive the analytical bit error ratio (BER) expression for binary chirp spread spectrum (BCSS) in the presence of multiple access interference (MAI) caused by correlation with other user signals because of either asynchronism or Doppler shifts, or both, and validate with simulations. To achieve this we analyze the signal cross correlations, and compare traditional linear chirps with our recently-proposed nonlinear chirps introduced in [1] and with other nonlinear chirps from the literature. In doing so we illustrate the superior performance of our new nonlinear chirp designs in these practical conditions, for the noncoherent counterpart of [1].
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[Citation]: https://ieeexplore.ieee.org/document/9391731
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The 3rd generation partnership project (3GPP) long term evolution (LTE) standard uses single carrier frequency division multiple access (SC-FDMA) scheme for the uplink transmissions and orthogonal frequency division multiplexing access (OFDMA) in downlink. In this paper, we point on the Peak-to-Average Power Ratio (PAPR) reduction for the uplink SC-FDMA system. Firstly, the conventional Tone Reservation (TR) is investigated. Then, the approach SOCP (Second Order Cone Programming) is applied for the complex baseband signals of SC-FDMA system with different subcarrier mapping. For the method TR, these subcarriers are located on unused subcarriers of SC-FDMA and we use a raised-cosine pulse. Besides, we prove that the IFDMA can be reduced the PAPR more than the localized FDMA (LFDMA) and distributed FDMA (DFDMA). Finally, this method does not degrade the bit-error-rate (BER) and the data bit rate and no side information (SI) transmission is obligatory.

In this paper a scheme is proposed for image transmission over Orthogonal Frequency Division Multiplexing (OFDM) systems using LDPC.As High PAPR overcomes the advantages of OFDM so Trigonometric transforms are used in this scheme for improving the performance of the OFDM systems by reducing the Peak to Average Power Ratio (PAPR) of OFDM signal. SPIHT is used for source coding of images to be transmitted. Then, the transmitted data of each parallel subchannel is modulated by Binary phase Shift Keying (BPSK) modulation because it provides high throughput and best performance when combined with the OFDM. Finally, the modulated data are fed into an IFFT circuit, such that the OFDM signal is generated.In the proposed scheme the transmit data sequence of the OFDM signal after Inverse Fast Fourier Transform (lFFT) is grouped into inphase and in-quadrature components, then each component is transformed using either the Discrete Cosine Transform (DCT) or the Discrete Sine Transform (DST). The simulation results show that adding the DST to the system reduces the PAPR of OFDM signal more than the DCT. which The simulation results show that adding the DST to the system improves the visual quality of reconstructed image.

The multifold increase in multimedia technology triggers an insatiable thirst for high data rates and increased demand for Orthogonal Frequency Division Multiplexing based wireless systems, a superior technology for the high-speed wireless communication systems. OFDM technique possesses multiple benefits superior to its predecessor, namely, its high capacity and resistance to multipath fading channels. Nonetheless, few hurdles remain yet unresolved in OFDM systems. The foremost issue stands out to be the high Peak to Average Power Ratio, which results in non-linearity in the High-Power Amplifiers and drives In-Band Distortion and Out-Of-Band Emission. Research plans are currently under development to standardize, given the economic 5G boom for market commercialization. The rise of superior waveform competitors possessing higher spectrum throughput, lower Peak to Average Power Ratio having a more straightforward system design than the celebrated OFDM. Potential candidates include numerous single carrier and multi-carrier waveforms. This paper undertakes an assessment, highlights the strengths and weaknesses of various 5G waveform candidates under the Key Performance Indicators, Simulation is carried out to study the PAPR reduction capabilities of these waveforms

Risk is defined as the probability of a specific adverse event occurring within a specific period, while Quantitative risk assessment (QRA) is the development of a quantitative estimate of risk based on engineering evaluation and mathematical techniques by combining estimate of incident consequences and frequencies. In view of the increase in the use, of railways as the mode of transportation for hazardous materials throughout the world, the associated risk analysis should be taken into concern. In this study, the failure frequency of the transportation of ammonia from the Petronas fertilizers Kedah (PFK) plant in Gurun (Northern part of Peninsular Malaysia), to the Chemical Company Malaysia (CCH) fertilizer's facilities in Port Mang (Soutb-western part of Peninsular Malaysia) was evaluated by incorporating the human error assessment. The study highlighted the importance of human error contributions in the failure frequency analysis and its impact on the selected failure scenarios. Besides, it also shows that the application of the human error assessment and reduction technique (HEART), which is a useful human reliability analysis tool, should be used in parallel with the fuzzy arithmetic approach to reduce the uncertainties involved in the estimation of human error probabilities, and hence, to reduce the likelihood of incorrect risks estimates being assessed. The results suggested that the commonly applied approach in quantitative risk assessments, which only consider equipment failures in the failure frequency estimations, are clearly an underestimate of the potential causes of failures leading to hazardous material releases, and hence, the calculated risks based do not reflect the actual risks. © 2008 American Institute of Chemical Engineers.

http://onlinelibrary.wiley.com/doi/10.1002/prs.10268/abstract