Download or read book Peak to Average Power Ratio Reduction in Orthogonal Frequency Division Multiplexing Using a Discrete Combined Transform written by Chak Hong Hum and published by . This book was released on 2007 with total page 326 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Peak to average Power Ratio Reduction in Orthogonal Frequency Division Multiplexing written by Sidharth Khanna and published by . This book was released on 2007 with total page 154 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A Simple and Effective Peak to average Power Ratio Reduction Approach Based on Iterative Companding Transform and Filtering Framework of Orthogonal Frequency Division Multiplexing Signal written by Thenappan T. Thiagarajan and published by . This book was released on 2017 with total page 38 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: The peak-to-average power ratio (PAPR) reduction in OFDM is an unresolved issue. Intense research has been carried out to solve the issue of peak power and to reduce the impact on overall system performance. PAPR can negatively affect system performance by inducing spectral regrowth and degrading detection efficiency. The purpose of this study is to show how the iterative companding transform and filtering (ICTF) framework can solve the PAPR issue in a redefined way. ICTF is able to obtain low out-of-band interference (OBI) and improved bit error rate (BER) while reducing PAPR significantly. Simulation results show good performance, low complexity, and reliable efficiency over traditional state of methods such as the iterative clipping and filtering technique.

Download or read book Peak to Average Power Ration Reduction and Bit Error Rate Improvement in Wireless Orthogonal Frequency Division Multiplexing Communication Systems written by Wisam Fahmi Al-Azzo and published by . This book was released on 2009 with total page 390 pages. Available in PDF, EPUB and Kindle. Book excerpt: Orthogonal frequency division multiplexing (OFDM) offers high data rate transmission with high spectral efficiency, immunity to multipath fading, and simple implementation using fast Fourier transform (FFT). OFDM is readily implemented by present day processors in many high speed networks. However, one of the major drawbacks of OFDM systems is the high peak-to-average power ratio (PAPR); this can result in poor power efficiency, degradation in bit-error-rate (BER) performance, and spectral spreading. The effective PAPR reduction of OFDM signals by simple processing has been challenge for the limited power and processing capability of portable OFDM applications. This thesis investigates the problem of high PAPR in OFDM systems and presents many simple implementation PAPR reduction techniques, and one error-resilient technique. The first part of this thesis presents two time-domain PAPR reduction techniques, viz, square-rooting the envelope of the OFDM output signals, and the smoothing technique. The square-rooting process changes the statistical distribution of the OFDM output signals from Rayleigh to Gaussian-like distribution and reduces the differences between the value of peak and average power, which consequently reduces the PAPR significantly. About 6 dB reduction in PAPR is achieved with moderate degradation in BER performance. For the smoothing process, which is derived from the image enhancement technique, the smoothing applied on the OFDM signals mitigates the PAPR due to its averaging effect. Up to 2.5 dB reduction is achieved by smoothing. Two new probabilistic based non-iterative frequency-domain PAPR reduction techniques are introduced in the second part of the thesis. These techniques reduce PAPR by changing the statistical distribution of the OFDM modulated symbols from uniform distribution to Gaussian-like distribution. This task is performed by two different methods in two different PAPR techniques. The first method of PAPR reduction is done by the addition of complex Gaussian random signals, while the second one is done by insertion of dummy Gaussian subcarriers. The two techniques provide PAPR reduction in the order of 5 dB for PSK-OFDM systems with no out-of-band radiation. The adaptive operation of these techniques enhances significantly both the BER performance and reduce the transmission power. The last part of this thesis presents a new modulation-based error resilient technique referred to as multi-dimensional modulation technique (MDM). In this technique concatenation of digital modulators of decreasing modulation orders are employed. The MDM technique improves the BER performance linearly with increased size of modulation order; up to 12 dB improvement in Eb/No is achieved relative to the conventional OFDM systems at high modulation orders, M≥1024. Also, the MDM technique offers both error resilience and PAPR reduction when it is combined with the conventional OFDM systems in time domain. As a conclusion, the proposed techniques described above offer new solutions to the problem of high PAPR in OFDM systems, and for one of them offer improvement of BER performance at the same time. Besides, they can be applied for different systems parameters and applications requirement. Moreover, the PAPR reduction techniques proposed in this thesis are data-independent and can be implemented in one-shot; while the MDM technique uses only digital modulation and dc-offset signal processing, which can be implemented by simple circuits and/or processors.

Download or read book Advanced Orthogonal Frequency division Multiplexing Systems with Cyclic Prefix less Multiple input and Multiple output Discrete Fourier Transform Spreading and Unmanned Aerial Vehicles assisted Cyclic Postfixed Windowed Schemes written by Md Mainul Islam Mamun and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the proper designing of spectrally efficient 5th Generation (5G)/Beyond 5G (B5G) systems, minimization of Peak-to-Average Power Ratio (PAPR) of the time domain Orthogonal Frequency-Division Multiplexing (OFDM)/Cyclic Prefix (CP)-less OFDM signal and reduction of baseband signal Out-of-Band (OOB) spectral power in the vicinity of boundaries of the transmission frequency band is very much essential. In the perspective of considering the non-compatibility of CP-less Single-Input Single-Output (SISO) OFDM technique with Multiple-Input Multiple-Output (MIMO) technology adopted 5G systems, we present the first CP-less MIMO OFDM System. It is based on incorporating Discrete Fourier transform (DFT) spreading, signal discrimination with Walsh-Hadamard coding, and PAPR reduction with Tukey (tapered cosine) time-domain windowing techniques. This combination of mechanisms provides an effective combination of benefits related to Bit Error Rate (BER), PAPR, Complementary Cumulative Distribution Function (CCDF) of PAPR, and OOB spectral power. The BER performances of our system in its simplified (SISO) form are compared with the CP-less SISO OFDM system. Additionally, the estimated OOB powers are also compared with various future-generation wireless communication systems such as DFT-Spread Windowing and Restructuring Orthogonal Frequency Division Multiplexing (WR-OFDM), Universal Filtered Multi-Carrier (UFMC) and Filter Bank Multi-Carrier (FBMC). Our simulation study shows that the proposed scheme achieves OOB spectral power attenuation of 142 dB with PAPR of 8.56 dB and BER of 10−4 under a scenario of Signal-to-Noise Ratio (SNR), Eb/N0 = 15 dB with 16-Quadrature Amplitude Modulation (16-QAM) modulation. To improve the spectral efficiency and robustness of wireless communication systems, on the other hand, drone-assisted 5G and beyond 5G wireless communication networking capabilities require strong consideration of constrained transmission power, user equipment receiver sensitivity, coverage area, and severe mmWave path loss. We present a Non-terrestrial downlink wireless communication system using a Cyclic Postfixed Windowed Orthogonal Frequency Division Multiplexing (CPW-OFDM) signal format. We demonstrate the impact of combining a Tukey windowing technique with Clipping and Filtering (CF) techniques for the simultaneous reduction of both OOB energy and PAPR. Block Diagonalization (BD) channel precoding provides Multi- user Interference (MUI) reduction, while (3,2)- Single Parity Check (SPC), Repeat and Accumulate (RA) channel coding, and Zero Forcing (ZF) signal detection schemes improve BER. Numerical results confirm that the proposed Non- terrestrial downlink CPW-OFDM system is suitable for multi-user signaling on mmWave frequencies.

Download or read book Peak to Average Power Ratio Reduction in OFDM Systems written by Anusha Chacko and published by LAP Lambert Academic Publishing. This book was released on 2015-04-17 with total page 60 pages. Available in PDF, EPUB and Kindle. Book excerpt: Orthogonal Frequency Division Multiplexing (OFDM) is a promising technology in wireless communication. High Peak-to-Average Power Ratio (PAPR) is one of the challenging issues of OFDM systems. High PAPR forces the High Power Amplifier (HPA) to operate in its linear region with wide dynamic range, where the power efficiency is very poor. This book gives an overview of different PAPR reduction techniques. And deals in detail with the efficient use of Selected Mapping (SLM) and Partial Transmit Sequence (PTS)technique to reduce high PAPR in OFDM systems.

Download or read book ORTHOGONAL FREQUENCY DIVISION MULTIPLEXING written by Mrs. Madhuri Pocha and published by Archers & Elevators Publishing House. This book was released on with total page 83 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Peak to Average Power Ratio PAPR Reduction in Orthogonal Frequency Division Multiplexing OFDM Communication Systems written by Xuefu Zhou and published by . This book was released on 2002 with total page 154 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Nonlinear Transform Approach to the Reduction of Peak to average Power Ratio in Orthogonal Frequency Division Multiplexing OFDM Systems written by Serkan Dursun and published by . This book was released on 2010 with total page 168 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Peak to Average Power Ratio Reduction in Orthogonal Frequency Division Multiplexing Systems Using Complementary Codes written by Brendan Michael Hill and published by . This book was released on 2005 with total page 198 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A New Scheme for Reduction of Peak to average Power Ratio in Orthogonal Frequency Division Multiplexing written by Ahmed Mustafa H. Melad and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Orthogonal Frequency Division Multiplexing (OFDM) is an attractive modulation method ror channels with a non-flat frequency response. as it saves the need for complex equalizers. However. its main disadvantage is the high peak-to-average power ratio (PAPR) of the output signal, which may take values within a range that is proportional to the number of carriers in the system. As a result, a linear behavior of the system over a large dynamic range is needed and therefore the efficiency of the output amplifier is reduced. Many methods have been proposed to reduce the PAPR of the OFDM signal. among them a clipping technique which has been focused and investigated. OFDM signal, among them a clipping technique which has been focused and investigated. This thesis proposes a new scheme to reduce the PAPR. We name it Off technique. Further the effects of clipping scheme as well as the new scheme on the OFDM system performance in terms of Bit Error Rate (BER) and PAPR reduction is investigated. The results obtained indicate that both parameters, i.e. the reduction in PAPR and BER of this scheme were worse than those of the Clipping Scheme. In conclusion, results indicate that Off Technique does not offer a better solution to P APR reduction in the OFDM system.

Download or read book New Peak to average Power Ratio Reduction Schemes for OFDM Systems written by Peng Liu and published by . This book was released on 2004 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: It is known that the orthogonal frequency division multiplexing (OFDM) modulation is very suitable for high-speed wireless transmission systems due to its bandwidth efficiency and ability in coping with multipath fading. However, the large peak-to-average power ratio (PAPR) of an OFDM signal limits the application of OFDM to a certain degree. The research focus of this thesis is on the study of some new PAPR reduction schemes for OFDM systems. In the first part of the thesis, we investigate the peak windowing method, the clipping method, and a combination of the two techniques with an emphasis on the performance assessment of the transmitted OFDM signal using the combination scheme. We start with the review of the two typical signal distortion techniques and point out their advantages and shortcomings. We then propose a combination scheme for the two techniques in order to overcome their drawbacks. In the proposed combination scheme, a weighting function is used to remove instantaneous signal peaks and then a hard-limiting is utilized for the reduction of the overall peak powers. A modified IDFT interpolation is developed and employed in the combination scheme to improve the interpolation precision of the time-domain OFDM signal. (Abstract shortened by UMI.).

Download or read book Peak to Average Power Ratio Reduction Using the Clipping Technique in Orthogonal Frequency Division Multiplexing System written by Wan Hafiza Wan Hassan and published by . This book was released on 2006 with total page 278 pages. Available in PDF, EPUB and Kindle. Book excerpt: The demand for high-speed mobile wireless communications is rapidly growing. The orthogonal frequency division multiplexing (OFDM) technology promises to be a key technique for achieving the high data capacity and spectral efficiency requirements for wireless communication systems of the near future. With its natural resistance to multipath fading and its capability to support extremely high data rates, OFDM is a major candidate for a fourth generation system. Despite many advantages of OFDM, it has two major drawbacks which are high peak to average power ratio (PAPR) and sychronization problem. A high PAPR causes saturation in power amplifiers, leading to intermodulation products among the sub carriers and disturbing out of band energy. Therefore, it is desirable to reduce the PAPR by means of PAPR reduction schemes. Clipping has been identified as the simplest yet effective technique of PAPR reduction. However, we have found out that clipping has resulted in the degradation of BER and enhanced the growth of out of band radiation leading to the degradation of the OFDM overall performance. As a solution, we have proposed an enhanced OFDM system with the objectives of reducing the high PAPR values while minimizing the effects of clipping. The convolutional coding scheme incorporated into the proposed system as a forward error control (FEC) scheme to improve the performance of BER in OFDM system. Besides, oversamples IFFT and digital filtering techniques are introduced into the system to minize the out of band radiation (OOBR). In this thesis, we have shown that the proposed system has significantly enhanced the BER performance and minimized the OOBR. However, there are a few trade-off which affected the overall performance. Hence, we have identified the optimum designed parameters which have resulted in a maximum PAPR reduction and OOBR suppression capability of 9 dB and 52 dB respectively at the cut-off BER of 10-4. In comparison to the existing proposed systems, our proposed system can be considered as one of the optimum system as it offers good PAPR reduction as well as OOBR suppression and comparable BER performance at the lowest value of SNR.

Download or read book Peak to Average Power Ratio Reduction Technique on Orthogonal Frequency Division Multiplexing OFDM Using Reed Rolomon Code written by Nur Izwani Mohd Fuad and published by . This book was released on 2011 with total page 71 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Optimized Framework for Reduction of Peak to Average Power Ratio in Orthogonal Frequency Division Multiplexing System by Weighted Approach written by Suma Manasa Ponnamaneni and published by . This book was released on 2015 with total page 22 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: In the 21st century the role of wireless communications has increased tremendously, especially mobile communication and high speed internet usage. Orthogonal Frequency Division Multiplexing (OFDM) communication technique has far more advantages over traditional communication techniques in terms of data rate, spectral efficiency and low fading. However, it still has a few drawbacks like Peak to Average Power Ratio (PAPR) which causes distortion at the transmitter part of the OFDM. The weighted OFDM approach has been proposed to reduce the PAPR without distortion and successfully remove the respective weight at the receiver end. The proposed method mainly intends to impose some weight on each discrete OFDM signal with certain amount of band limited signal and finally a weighted discrete OFDM signal is formed before it is given to High Power Amplifier (HPA). At the receiver end the same original signal should be received completely but the only condition in this approach is that the time taken at both transmitter and receiver end should be the same. Finally the efficiency and the performance of the proposed weighted scheme are evaluated by the simulation results. The numerical analysis acquired from the proposed weighted scheme reveals that the PAPR of weighted technique is lesser than the conventional clipping and filtering (CF) method and the Bit Error Rate (BER) performance also improved a lot when compared to the CF method.

Download or read book Minimizing Peak to average Power Ratio in an Orthogonal Frequency Division Multiplex System written by and published by . This book was released on 2014 with total page 129 pages. Available in PDF, EPUB and Kindle. Book excerpt: Orthogonal frequency division multiplexing (OFDM) is a popular standard in wireless communication for its enabling high throughput data transfer. However, the OFDM signal usually has a high peak-to-average power ratio (PAPR), which requires a wide-dynamic-range, powerconsuming amplifier. Whenever the signal peak is greater than the amplifier linear region, the signal is distorted. This distortion generates interference in both in-band and out-of-band spectrum. The effect of in-band interference becomes apparent at medium to high SNR levels and reduces system performance gains as the SNR increases. We endeavor to improve the system BER by minimizing the signal peak using signal scrambling techniques. These techniques effectively reduce the signal peak and enhance system performance when the receiver is able to correctly decode the scrambling information. This information is a weakness of existing techniques because a resource is needed to transport it, and its corruption dramatically undermines system performance. We propose a novel scheme that utilizes resources allotted for channel estimation and does not need to transmit explicit scrambling information. Therefore, our technique improves over the existing ones in the same category. In addition, we propose some procedures to alleviate scrambling information corruption and show discernible advancements. We study the trade-off between PAPR reduction and channel estimation when they have to compete for the same resource. We suggest doing PAPR reduction only when the receiver can obtain a good channel estimate to ensure favorable system performance.

Download or read book Selective Mapping technique for PAPR reduction in LTE OFDM Systems written by Neelam Dewangan and published by GRIN Verlag. This book was released on 2012-11-22 with total page 100 pages. Available in PDF, EPUB and Kindle. Book excerpt: Master's Thesis from the year 2012 in the subject Engineering - Communication Technology, grade: none, , course: M.Tech, language: English, abstract: As a promising technique, OFDM has been widely used in emerging broadband communication systems, such as digital audio broadcasting (DAB), high-definition television (HDTV), wireless local area network (IEEE 802.11a and HIPERLAN/2). However, as the OFDM signals are the sum of signals with random amplitude and phase, they are likely to have large PAPR that requires a linear high-power- amplifier (HPA) with an extremely high dynamic range, which is expensive and inefficient. Furthermore, any amplifier nonlinearity causes intermodulation products resulting in unwanted out-of-band power. A number of approaches have been proposed to deal with the PAPR problem, including clipping, clipping-and-filtering (CF), coding, companding transform, active constellation extension (ACE), selected mapping (SLM), partial transmit sequence (PTS), and so on. This thesis proposes an improvement in Selected Mapping technique and Simulation results are compared to existing techniques namely Exponential Companding Transform, Repeated Clipping and Filtering and Adaptive Active Constellation Extension. The improvements which are proposed in classical Selective Mapping technique satisfies the PAPR Reduction criteria with reducing the computational complexity. Also this new scheme has an important advantage of avoiding the extra bits along with the transmitted OFDM signal .This scheme can also be applied to the multiple transmitting antenna cases.