Peak to average power reduction techniques in OFDM

2014

Orthogonal frequency division multiplexing (OFDM) is a multicarrier modulation technique which uses orthogonal subcarriers to convey information. Orthogonal frequency division multiplexing (OFDM) has been adopted as a standard for various high data rate wireless communication systems due to the high spectral bandwidth efficiency, robustness to frequency selective fading channels, well suited for mimo technology, Facilitate frequency-domain scheduling supports flexible bandwidth deployment etc. However, implementation of the OFDM system entails several difficulties. One of the major drawbacks is the high peak-to-average power ratio (PAPR) problem in multicarrier transmission system which leads to power inefficiency in RF section of the transmitter, inter carrier interference, high out-of-band radiation, and bit error rate performance degradation. It is preferred to have a minimum PAPR, as it will allow a higher average power to be transmitted for a fixed peak power; and thus, improvi...

2015

With the advancement in wireless communication systems and the increase in demand for high data rates, Orthogonal Frequency Division Multiplexing (OFDM) has proved to be a key technology for the future 3G and 4G wireless communication system. OFDM offers a considerable high spectral efficiency, multipath delay tolerance, immunity to the frequency selective fading channels and power efficiency. However, one major disadvantage of OFDM system is the high PAPR (Peak to Average Power Ratio) of the transmitted signal. A number of techniques are employed to reduce PAPR ratio. In this paper, various techniques proposed for PAPR reduction techniques have been discussed along with the criteria of their selection. This paper provides an intuitive knowledge of the concept used with the comprehensive and comparative review of some PAPR reduction techniques.

Maǧallaẗ ǧāmiʻaẗ kirkūk, 2022

This paper is concerned with the Orthogonal Frequency Division Multiplexing (OFDM) system that is adopted by a wireless communication system for transmitting multicarrier modulated signals simultaneously with robustness against interference and noise facing the system. It presents a significant issue related to the OFDM system known as the raise of Peak to Average Power Ratio (PAPR) that is the high peaks of OFDM signals compared to its average power. Increasing the PAPR yields in the component devices of the OFDM system does not cope with the high peaks resulting in distortion and signal losses. Therefore, the objective of this article is to review different approaches of PAPR reduction techniques and compare them to select the best technique for a particular system. The approaches are mainly of three classifications; distortion, probabilistic, and coding schemes with each including several techniques.

IEEE Transactions on Broadcasting, 2000

One of the challenging issues for Orthogonal Frequency Division Multiplexing (OFDM) system is its high Peak-to-Average Power Ratio (PAPR). In this paper, we review and analysis different OFDM PAPR reduction techniques, based on computational complexity, bandwidth expansion, spectral spillage and performance. We also discuss some methods of PAPR reduction for multiuser OFDM broadband communication systems. Index Terms-Complementary cumulative distribution function (CCDF), high power amplifier (HPA), multiuser OFDM, OFDM, peak-to-average power ratio (PAPR).

International Journal for Research in Applied Science and Engineering Technology, 2019

Wireless technologies have gradually become more and more involved into people's daily life. Among multicarrier transmission techniques, Orthogonal Frequency Division Multiplexing (OFDM) is the most popular one that uses parallel data streams. Compared with single carrier modulation, OFDM has many advantages as immunity to impulse interference, high spectral density, resilient to RF interference, robustness to channel fading, resistance to multipath, much lower computational complexity. In this paper, we will give an overview to OFDM technique, identify the PAPR problem and a technique for reducing PAPR (peak to average power ratio) in OFDM by changing the phase of some of the subcarriers.

TJPRC, 2013

Orthogonal Frequency Division Multiplexing (OFDM) is a promising technique used in the wireless broadband communication systems these days. It is a form of multi-carrier modulation technique. High spectral efficiency, robustness to channel fading, immunity to impulse interference, uniform average spectral density, capacity to handle very strong echoes and very less nonlinear distortion are the properties of the OFDM. Every system has some drawbacks because nothing is ideal in the universe. In this system the major drawback that we observe is Peak-to-Average Power Ratio (PAPR). In this paper, we emphasize on PAPR (Peak –to-Average Power Ratio) which shows serious effect on the performance of system. We discuss various reduction techniques with the advantages, disadvantages and highlighted the selective mapping technique (SLM) using Complementary Cumulative Distribution Function (CCDF) with different route numbers. SLM is efficient when number of subcarriers is large. The simulation results clearly show that PAPR is inversely proportional to the route numbers.

International Journal of Engineering Research and Technology (IJERT), 2014

https://www.ijert.org/performance-analysis-of-peak-to-average-power-ratio-reduction-techniques-in-ofdm-system https://www.ijert.org/research/performance-analysis-of-peak-to-average-power-ratio-reduction-techniques-in-ofdm-system-IJERTV3IS030524.pdf Orthogonal Frequency Division Multiplexing (OFDM) is an efficient modulation scheme proposed for high data rate applications. OFDM is a multiple carrier modulation technique. It distributes data over a large number of sub-carriers spaced apart at precise frequencies, such that they are orthogonal to one another. OFDM has been successfully applied to a wide variety of digital communication applications over the past several years including digital TV broadcasting, digital audio broadcasting, Asynchronous Digital Subscriber Line (ADSL) modems and wireless networking worldwide. Its application in mobile communication is more complex especially because of the mobility of the mobile user; thus more exact symbol timing and frequency-offset control must be used to ensure that sub-carriers remain orthogonal. An OFDM signal consists of a number of independently modulated subcarriers, which can give a large crest factor or Peak-to-Average Power Ratio (PAPR) when added up coherently. This poses problem regarding the linear bandwidth of the RF amplifiers. In this paper, different PAPR reduction techniques are analysed and compared with standard OFDM.

2006 International RF and Microwave Conference, 2006

Orthogonal Frequency Division Multiplexing (OFDM) is a special form of multicarrier modulation which is robust against the multipath effect, Intersymbol Interference (ISI) and high spectral efficiency. However, Peak to Average Power Ratio (PAPR) is a major drawback in the system since this leads to the distortion problem in the linear devices such as the power amplifier (PA). Thus, the PAs require a backoff which is approximately equal to the PAPR for distortionless transmission. This decreases the efficiency for amplifiers. Hence, reducing the PAPR is the main focus of this paper. One of the available PAPR solutions is clipping. In the technique, the efficiency does not depend on the number of carriers. This paper investigates the effectiveness of the clipping technique by focusing on the performance of PAPR value with different values of clipping ratios (CRs) and the relationship between PAPR value and Bit Error Rate (BER).

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Third World Quarterly, 2016

This paper works to unpack the different dimensions of the links between Africa and China including the "untold story" of this relationship, which characterized by evolving Sino-Africa relations in which African states now have an opportunity to build for themselves an increasingly assertive role when it comes to investment and signing trade deals, ensuring that labour, environmental, and human rights are respected. The paper examines the extent to which China holds sway over Africa as it once did, given the emergence of other emerging powers in and outside the continent. In short, it is argued that China's relationship with Africa has transformed into one defined by a emerging dynamism and African agency, characteristics which have the capacity to lessen the hold the former previously had on Africa, if captured and leveraged appropriately. The paper's first section engages in a comprehensive literature review of historical Sino-African relations, from the early Han dynasty to its contemporary manifestations, denoting how these linkages have swayed, evolved, ebbed, and flowed according to domestic interests and international/external pressures. Section Two continues this analysis by focusing exclusively on the status quo and contemporary shifts in the Sino-African economic relationship, including analysis of trade flows, investments, development, economic cooperation, and Chinese support for regional integration. The paper then concludes with an elaboration of some key, emerging relationship areas, inclusive of challenges which must be overcome and opportunities for collaboration, thereby supporting the resurgence of African agency, interests, and objectives in their relations with China.