Download or read book Fast Peak power Reduction for MIMO OFDM Systems with Diversity written by Theodoros Tsiligkaridis and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A robust peak-power reduction technique called active constellation extension (ACE) reduces the peak-to-average power ratio (PAPR) of single-input single-output (SISO) orthogonal frequency-division modulated (OFDM) signals by extending the outer constellation points in a way that minimizes the PAPR of an OFDM transmit signal, without reducing the bandwidth or increasing bit error rate (BER). Recent work includes extensions of the concept of ACE using a modi ed smart gradient-project algorithm for MIMO-OFDM systems. We extend the e cient ACE smart gradient-project (SGP) method to space-time block coded (STBC), space-frequency block coded (SFBC) and V-BLAST OFDM systems. The proposed peak-power reduction method can be applied to any space-time-frequency (STF) block code, and its performance is bounded by the code structure. Simulations show PAPR reduction gains of 4.19 and 3.57 dB under QPSK for Alamouti STBC and SFBC, respectively. In addition, we extend the e cient ACE-SGP method to rotated constellations for SISO-OFDM systems, an alternative method recently invented for providing diversity. Simulation results show approximately 3.46 dB and 2.08 dB of PAPR reduction for QPSK and 16-QAM original constellations, respectively, for 256 subcarriers. Results also show that 4.29 dB and 3.41 dB of PAR reduction are obtained for QPSK and 16-QAM original constellations, respectively, for 1024 subcarriers. Furthermore, we show how the PAPR reduction method known as tone injection can be a very practical transmission scheme for coded-OFDM systems, with a slight compromise of the BER performance. This is accomplished by developing e cient, near-optimal, convolutional and LDPC decoders for the extended non-bijective constellations introduced by tone injection. Simulation results for convolutional and LDPC coded-OFDM systems show BER performance comparable to conventional coded OFDM with greatly reduced PAPR. Furthermore, results show that the PAPR performance obtained is very close to the 64-QAM single-carrier peak-power performance. So, the peak-power problem is solved for large constellations.

Download or read book Peak to Average Power Ratio Reduction for MIMO OFDM Systems written by Isabela Braz and published by . This book was released on 2010 with total page 104 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Peak to Average Power Ratio PAPR Reduction in MIMO OFDM System written by Gangat Mohsin Salim and published by . This book was released on 2016-06-07 with total page 72 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book PAPR Reduction Techniques Analysis and Applications written by Dr. RAJKUMAR L. BIRADAR and published by Archers & Elevators Publishing House. This book was released on with total page 85 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Orthogonal Frequency Division Multiplexing with Diversity for Future Wireless Systems written by Khoa N. Le and published by Bentham Science Publishers. This book was released on 2012 with total page 621 pages. Available in PDF, EPUB and Kindle. Book excerpt: "The book examines several aspects of Orthogonal Frequency Division Multiplexing (OFDM) employing linear diversity techniques such as inter-carrier interference, bit error rate, peak to average power and inter-block interference. It should be a useful refe"

Download or read book Peak to Average Power Ratio Reduction in STBC MIMO OFDM written by Kishor Gannamaneni and published by . This book was released on 2014 with total page 71 pages. Available in PDF, EPUB and Kindle. Book excerpt: Orthogonal frequency division multiplexing (OFDM) is an advanced 3G/4G scheme which achieves high data rate and combats multipath fading. However, OFDM systems suffer from nonlinear peak to average power ratio (PAPR) and carrier frequency offsets (CFO). These two factors lead to degraded performance and thereby reducing the system efficiency. OFDM with multiple antennas both at transmitter and receiver and space-time block coding is used to increase the channel capacity and receiver diversity. Space-time block coding is used to increase data rate and for reliable communications. With space-time block coding we can take advantage of both space and time. It is also possible to implement spatial multiplexing using space-time block coding. However, MIMO-OFDM also suffers from high PAPR value. Many methods have been proposed to reduce the PAPR problem in OFDM. Distortion techniques, coding techniques and scrambling techniques are some of those methods. These methods can be extended to MIMO-OFDM. Distortion techniques can reduce the PAPR, but in turn it increases bit error rate. Coding techniques have limitations with number of subcarriers. Scrambling techniques can reduce the PAPR effectively. In this paper we used SLM and PTS methods to reduce the PAPR problem in MIMO-OFDM. The bit error rate performance for each method is plotted and compared with each other. BER performance of MIMO is compared with SIMO and MISO.

Download or read book MIMO OFDM for LTE WiFi and WiMAX written by Lajos Hanzo and published by John Wiley & Sons. This book was released on 2011-07-05 with total page 708 pages. Available in PDF, EPUB and Kindle. Book excerpt: MIMO-OFDM for LTE, WIFI and WIMAX: Coherent versus Non-Coherent and Cooperative Turbo-Transceivers provides an up-to-date portrayal of wireless transmission based on OFDM techniques augmented with Space-Time Block Codes (STBCs) and Spatial-Division Multiple Access (SDMA). The volume also offers an in-depth treatment of cutting-edge Cooperative Communications. This monograph collates the latest techniques in a number of specific design areas of turbo-detected MIMO-OFDM wireless systems. As a result a wide range of topical subjects are examined, including channel coding and multiuser detection (MUD), with a special emphasis on optimum maximum-likelihood (ML) MUDs, reduced-complexity genetic algorithm aided near-ML MUDs and sphere detection. The benefits of spreading codes as well as joint iterative channel and data estimation are only a few of the radical new features of the book. Also considered are the benefits of turbo and LDPC channel coding, the entire suite of known joint coding and modulation schemes, space-time coding as well as SDM/SDMA MIMOs within the context of various application examples. The book systematically converts the lessons of Shannon's information theory into design principles applicable to practical wireless systems; the depth of discussions increases towards the end of the book. Discusses many state-of-the-art topics important to today's wireless communications engineers. Includes numerous complete system design examples for the industrial practitioner. Offers a detailed portrayal of sphere detection. Based on over twenty years of research into OFDM in the context of various applications, subsequently presenting comprehensive bibliographies.

Download or read book Peak Power Control in Multicarrier Communications written by Simon Litsyn and published by Cambridge University Press. This book was released on 2007-01-04 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt: Peak signal power is an important factor in the implementation of multicarrier (MC) modulation schemes, like OFDM, in wireless and wireline communication systems. This 2007 book describes tools necessary for analyzing and controlling the peak-to-average power ratio in MC systems, and how these techniques are applied in practical designs. The author starts with an overview of multicarrier signals and basic tools and algorithms, before discussing properties of MC signals in detail: discrete and continuous maxima; statistical distribution of peak power; codes with constant peak-to-average power ratio are all covered, concluding with methods to decrease peak power in MC systems. Current knowledge, problems, methods and definitions are summarized using rigorous mathematics, with an overview of the tools for the engineer. The book is aimed at graduate students and researchers in electrical engineering, computer science and applied mathematics, and practitioners in the telecommunications industry.

Download or read book An Investigation of Peak To Average Power Reduction written by Yi Wang and published by LAP Lambert Academic Publishing. This book was released on 2010-06 with total page 76 pages. Available in PDF, EPUB and Kindle. Book excerpt: Multiple-input multiple-output orthogonal frequency division multiplexing (MIMO-OFDM) technology is one of the most attractive candidates for fourth generation(4G)mobile radio communication. It effectively combats the multipath fading channel and improves the bandwidth efficiency. At the same time, it also increases system capacity so as to provide a reliable transmission. However, the main drawback of MIMO-OFDM system is high peak-to-average power ratio (PAPR) for large number of sub-carriers, which result in many restrictions for practical applications. Coding, phase rotation and clipping are among many PAPR reduction schemes that have been proposed to overcome this problem. In this thesis, we will mainly investigate the PAPR reduction performance with two different PAPR reduction methods: partial transmit sequence (PTS) and selective mapping(SLM). These two methods are sub- entities of phase rotation scheme. In addition, several corresponding modified algorithms are studied with respect to balanced performance and applicability.

Download or read book Space time frequency Coded Mimo and Cooperative OFDM Systems written by Zhefeng Li and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Space-time-frequency coded Multiple-Input and Multiple-Output Orthogonal Frequency Division Multiplexing (MIMO-OFDM) systems have recently attracted much attention for broadband wireless communications including recent IEEE standards 802.11n and 802.16e. Space-time/Frequency Coding (SFC) can achieve the spatial and multipath diversities for a MIMO-OFDM system by coding across multiple antennas and subcarriers. In this research, we focus on a family of space-time-frequency codes proposed by Zhang et al to achieve both full spatial and multipath diversities by using Orthogonal Space-Time Block Codes (OSTBC). In particular, we develop a precoding algorithm for Peak-to-Average Power Ratio (PAPR) reduction and a clipping noise model based Maximum Likelihood (ML) decoding algorithm for Space-Time-Frequency Block Codes (STFBC) coded MIMO-OFDM systems. An important issue for OFDM systems is their high PAPR and it is important to reduce the PAPR in a practical (power efficient) system. The first goal of this research is to modify the repeating process and adjust phases of coded symbols so that the PAPR of the OFDM system is reduced. In particular, we propose to use Chu sequences for phase adjustment and show that the discrete PAPR can be reduced by & Gamma; times where & Gamma; is the times of the repeating across subcarriers. Another efficient way to reduce the PAPR in OFDM systems is clipping. After the clipping in an MIMO-OFDM system, the overall additive noise, including the clipping distortion, may not be white. The second goal of this research is to develop fast ML decoding algorithms for Orthogonal Space-Time-Frequency Block Codes (OSTFBC) and Quasi Orthogonal Space-Time-Frequency Block Codes (QOSTFBC) in clipped MIMO-OFDM systems. By using a clipping noise model with Gaussian approximation, our newly proposed fast ML decoding algorithms improve the system performance without increasing the decoding complexity. Simulation results are presented to illustrate the improvement. In order to apply the clipping noise model based ML decoding, the clipping ratio needs to be known at the receiver. We also consider the case when the clipping ratio is not known at the receiver. So a decision-aided clipping ratio estimation for MIMO-OFDM systems is proposed in our research, too. Except for MIMO-OFDM systems, in this work, cooperative OFDM system is investigated too. OFDM transmission has been proposed for cooperative communications to combat the time delays from the relay nodes, where the paths from relay nodes to destination node are treated as multipaths and space-time (or frequency) coding is used to achieve the spatial (or multipath) diversity. With this approach, when the Cyclic Prefix (CP) length is less than the time delay length, inter-block interference occurs. In this research, we consider Alamouti coded OFDM systems in cooperative communications where the CP length may be less than the time delay length. By taking the advantage of the Alamouti code structure, we propose a time domain interference cancellation algorithm.

Download or read book Peak to Average Power Reduction for Multi antenna of OFDM Systems written by Madhan Jaganthan and published by . This book was released on 2008 with total page 124 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Peak to Average Power Ratio Reduction for Coded MIMO OFDM written by Harish Reddy and published by . This book was released on 2003 with total page 180 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Peak to average Power Ratio and Intercarrier Interference Reduction Techniques in MIMO OFDM System written by Sharifah Kamilah Syed Yusof and published by . This book was released on 2006 with total page 216 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Peak to Average Power Ratio Reduction and Error Control in MIMO OFDM HARQ System written by Francisco Alberto Sandoval Noreña and published by . This book was released on 2019 with total page 169 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Wireless OFDM and MIMO OFDM Communications written by P. Mukunthan and published by LAP Lambert Academic Publishing. This book was released on 2014-06-14 with total page 140 pages. Available in PDF, EPUB and Kindle. Book excerpt: The present wireless systems aim for two conflicting goals, viz., providing quality of service such as delay, fairness to users, and maximizing the throughput of the system. Several techniques have been developed for increasing bandwidth with high data rate. Among these techniques, Orthogonal Frequency Division Multiplexing (OFDM) is a special form of multicarrier technique where all the subcarriers are orthogonal to each other. OFDM offers higher data rate and high immunity to the multipath fading channel without degrading the Bit Error Rate (BER) performance. It has gained popularity for broadband communication system because of its high spectral efficiency and capacity to combat multipath fading. At the same time, it has some limitations such as Inter-Symbol Interference (ISI), Inter-Carrier Interference (ICI) and high Peak-to-Average Power Ratio (PAPR). This book contain seven chapters and an attempt has been made in this research work to enhance the power amplifier efficiency and reduce the high PAPR of the OFDM and MIMO-OFDM systems through modified PTS approach combined with some PAPR reduction techniques.

Download or read book 3rd International Conference on Movement Health and Exercise written by Fatimah Ibrahim and published by Springer. This book was released on 2017-01-20 with total page 189 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume presents the proceedings of the 3rd International Conference on Movement, Health and Exercise 2016 (MoHE2016). The conference was jointly organized by the Biomedical Engineering Department and Sports Centre, University of Malaya. It was held in Malacca, from 28-30 September 2016. MoHE 2016 provided a good opportunity for speakers and participants to actively discuss about recent developments in a wide range of topics in the area of sports and exercise science. In total, 83 presenters and 140 participants took part in this successful conference.

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.