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 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 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 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 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 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 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 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 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 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 Improvement of Peak to average Power Ratio Reduction in Orthogonal Frequency Division Multiplexing Systems Using Free Side Information Selected Mapping Method written by Sara Razavi and published by . This book was released on 2014 with total page 148 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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 and intercarrier interference reduction algorithms for orthogonal frequency division multiplexing systems written by Yajun Kou and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book An Implementation of Peak to Average Power Ratio Reduction for Multicarrier System orthogonal Frequency Division Multiplexing written by and published by . This book was released on 2015 with total page 98 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Bit Loading and Peak Average Power Reduction Techniques for Adaptive Orthogonal Frequency Division Multiplexing Systems written by and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In a frequency-selective channel a large number of resolvable multipaths are present which lead to the fading of the signal. Orthogonal frequency division multiplexing (OFDM) is well-known to be effective against multipath distortion. It is a multicarrier communication scheme, in which the bandwidth of the channel is divided into subcarriers and data symbols are modulated and transmitted on each subcarrier simultaneously. By inserting guard time that is longer than the delay spread of the channel, an OFDM system is able to mitigate intersymbol interference (ISI). Significant improvement in performance is achieved by adaptively loading the bits on the subcarriers based on the channel state information from the receiver. Imperfect channel state information (CSI) arises from noise at the receiver and also due to the time delay in providing the information to the transmitter for the next data transmission. This thesis presents an investigation into the different adaptive techniques for loading the data bits on the subcarriers. The choice of the loading technique is application specific. The spectral efficiency and the bit error rate (BER) performance of adaptive OFDM as well as the implementation complexity of the different loading algorithms is studied by varying any one of the parameters, data rate or BER or total transmit power subject to the constraints on the other two. A novel bit loading algorithm based on comparing the SNR with the threshold in order to minimize the BER is proposed and its performance for different data rates is plotted. Finally, this thesis presents a method for reducing the large peak to average power ratio (PAPR) problem with OFDM which arises when the sinusoidal signals of the subcarriers add constructively. The clipping and the probabilistic approaches were studied. The probabilistic technique shows comparatively better BER performance as well as reduced PAPR ratio but is more complex to implement.

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 Orthogonal Frequency Division Multiplexing for Wireless Communications written by Ye Geoffrey Li and published by Springer Science & Business Media. This book was released on 2006-05-31 with total page 314 pages. Available in PDF, EPUB and Kindle. Book excerpt: Orthogonal Frequency Division Multiplexing for Wireless Communications is an edited volume with contributions by leading authorities in the subject of OFDM. Its coverage consists of principles, important wireless topics (e.g. Synchronization, channel estimation, etc.) and techniques. Included is information for advancing wireless communication in a multipath environment with an emphasis on implementation of OFDM in base stations. Orthogonal Frequency Division Multiplexing for Wireless Communications provides a comprehensive introduction of the theory and practice of OFDM. To facilitate the readers, extensive subject indices and references are given at the end of the book. Even though each chapter is written by different experts, symbols and notations in all chapters of the book are consistent.