This document discusses a wavelet packet transform based fast Fourier transform (DWPT-FFT) and its application to signal-to-noise ratio (SNR) estimation in orthogonal frequency division multiplexing (OFDM) systems. The DWPT-FFT has the same computational complexity as the conventional FFT but provides finer frequency resolution. An SNR estimation technique is proposed that performs estimation inside the DWPT-FFT block, unlike previous methods that estimate SNR after FFT. The technique divides the OFDM band into sub-bands using wavelet packets and estimates noise power in each sub-band based on the autocorrelation of the transmitted preamble. The proposed estimator is compared to Reddy's estimator through simulations and shows improved performance in colored noise scenarios.
Performance Comparison of FFT, DHT and DCT Based OFDM Systems with BPSK as A ...paperpublications3
Abstract: Today, OFDM has grown to be the most popular communication system in high-speed communications. OFDM is becoming the chosen modulation technique for wireless communications. OFDM can provide large data rates with sufficient robustness to radio channel impairments. Different type of transform techniques such as Discrete Hartley transform (DHT), Discrete Cosine Transform (DCT), Fast Fourier Transform (FFT) are used to perform the modulation and demodulation operations for the OFDM system. In this paper these three transforms are used in OFDM and study the comparison between these different transforms techniques used in OFDM system based on Bit Error Rate (BER) performances.
Design of matched filter for radar applicationselelijjournal
The aim of this paper is to present the details of signal processing techniques in Military RADARS . These
techniques are strongly based on mathematics and specially on stochastic processes. Detecting a target in
a noisy environment is a many folds sequential process. The signal processing chain only provides to the
overall system boolean indicators stating the presence (or not) of targets inside the coverage area. It is
part of the strategical operation of the radar. This paper mainly focuses on Design of Matched filter and
generation of chirp Signal.
This document summarizes a research paper that proposes a scheme for image transmission over OFDM systems using LDPC coding and trigonometric transforms. It aims to improve OFDM performance by reducing peak-to-average power ratio (PAPR) and enhancing image quality. The scheme uses SPIHT for image source coding, BPSK modulation, and inserts DCT or DST transforms after IFFT. Simulation results show the DST transform most effectively reduces PAPR compared to DCT. Reconstructed images also have improved visual quality with DST. The scheme thus enhances OFDM systems for image transmission applications.
A Peak to Average Power Ratio (PAPR) Reduction in OFDM SystemsIRJET Journal
This document discusses peak-to-average power ratio (PAPR) reduction techniques for orthogonal frequency division multiplexing (OFDM) systems. It begins with an introduction to OFDM and the problem of high PAPR values in OFDM signals. It then describes the clipping and filtering method and parabolic peak cancellation method for PAPR reduction. It analyzes these techniques by evaluating complementary cumulative distribution function (CCDF) curves and bit error rate (BER) with the goal of minimizing PAPR while maintaining acceptable BER. Power amplifier nonlinearity is also discussed as a key factor affected by high PAPR OFDM signals.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
International Journal of Engineering Research and Applications (IJERA) is a team of researchers not publication services or private publications running the journals for monetary benefits, we are association of scientists and academia who focus only on supporting authors who want to publish their work. The articles published in our journal can be accessed online, all the articles will be archived for real time access.
Our journal system primarily aims to bring out the research talent and the works done by sciaentists, academia, engineers, practitioners, scholars, post graduate students of engineering and science. This journal aims to cover the scientific research in a broader sense and not publishing a niche area of research facilitating researchers from various verticals to publish their papers. It is also aimed to provide a platform for the researchers to publish in a shorter of time, enabling them to continue further All articles published are freely available to scientific researchers in the Government agencies,educators and the general public. We are taking serious efforts to promote our journal across the globe in various ways, we are sure that our journal will act as a scientific platform for all researchers to publish their works online.
This document discusses the process of sampling in signal processing. It defines key terms like analog and digital signals, sampling frequency, and samples. It explains how sampling works by taking regular measurements of a continuous signal's amplitude over time. This converts it into a discrete-time signal. It discusses applications of sampling like audio sampling, where signals are typically sampled above 20 kHz. It also discusses video sampling rates and speech sampling rates. The document contains examples and diagrams to illustrate these concepts.
Design of Scalable FFT architecture for Advanced Wireless Communication Stand...IOSRJECE
Now a day’s numerous wireless communication standards have raised additional stringent requirements on each throughput and flexibility for FFT computation. Advanced wireless systems support multiple standards to satisfy the demands of user application necessities. A wireless system whereas supporting multiple standards should also satisfy performance necessities of these supported standards. Meeting performance requirements of multiple standards is a challenge while designing a system. Fast Fourier transformations, a kernel processing task in communication systems, are studied intensively for efficient software and hardware implementations. To design an efficient system, it's necessary to efficiently design its performance critical component. each system must meet stringent design parameters like high speed, low power, low area, low cost, high flexibility and high scalability, designing FFT processor to support multiple wireless standards whereas meeting the above such performance necessities is a difficult task. This paper proposed a highly efficient scalable architecture, software tools design, and design implementation. The reconstruction of the FFT computation flow is design into a scalable structure. The FFT can be easily expanded for any-point FFT computation. The various parameters satisfied the conditions, gives proper and efficient outputs as compare to other platforms.
Performance Comparison of FFT, DHT and DCT Based OFDM Systems with BPSK as A ...paperpublications3
Abstract: Today, OFDM has grown to be the most popular communication system in high-speed communications. OFDM is becoming the chosen modulation technique for wireless communications. OFDM can provide large data rates with sufficient robustness to radio channel impairments. Different type of transform techniques such as Discrete Hartley transform (DHT), Discrete Cosine Transform (DCT), Fast Fourier Transform (FFT) are used to perform the modulation and demodulation operations for the OFDM system. In this paper these three transforms are used in OFDM and study the comparison between these different transforms techniques used in OFDM system based on Bit Error Rate (BER) performances.
Design of matched filter for radar applicationselelijjournal
The aim of this paper is to present the details of signal processing techniques in Military RADARS . These
techniques are strongly based on mathematics and specially on stochastic processes. Detecting a target in
a noisy environment is a many folds sequential process. The signal processing chain only provides to the
overall system boolean indicators stating the presence (or not) of targets inside the coverage area. It is
part of the strategical operation of the radar. This paper mainly focuses on Design of Matched filter and
generation of chirp Signal.
This document summarizes a research paper that proposes a scheme for image transmission over OFDM systems using LDPC coding and trigonometric transforms. It aims to improve OFDM performance by reducing peak-to-average power ratio (PAPR) and enhancing image quality. The scheme uses SPIHT for image source coding, BPSK modulation, and inserts DCT or DST transforms after IFFT. Simulation results show the DST transform most effectively reduces PAPR compared to DCT. Reconstructed images also have improved visual quality with DST. The scheme thus enhances OFDM systems for image transmission applications.
A Peak to Average Power Ratio (PAPR) Reduction in OFDM SystemsIRJET Journal
This document discusses peak-to-average power ratio (PAPR) reduction techniques for orthogonal frequency division multiplexing (OFDM) systems. It begins with an introduction to OFDM and the problem of high PAPR values in OFDM signals. It then describes the clipping and filtering method and parabolic peak cancellation method for PAPR reduction. It analyzes these techniques by evaluating complementary cumulative distribution function (CCDF) curves and bit error rate (BER) with the goal of minimizing PAPR while maintaining acceptable BER. Power amplifier nonlinearity is also discussed as a key factor affected by high PAPR OFDM signals.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
International Journal of Engineering Research and Applications (IJERA) is a team of researchers not publication services or private publications running the journals for monetary benefits, we are association of scientists and academia who focus only on supporting authors who want to publish their work. The articles published in our journal can be accessed online, all the articles will be archived for real time access.
Our journal system primarily aims to bring out the research talent and the works done by sciaentists, academia, engineers, practitioners, scholars, post graduate students of engineering and science. This journal aims to cover the scientific research in a broader sense and not publishing a niche area of research facilitating researchers from various verticals to publish their papers. It is also aimed to provide a platform for the researchers to publish in a shorter of time, enabling them to continue further All articles published are freely available to scientific researchers in the Government agencies,educators and the general public. We are taking serious efforts to promote our journal across the globe in various ways, we are sure that our journal will act as a scientific platform for all researchers to publish their works online.
This document discusses the process of sampling in signal processing. It defines key terms like analog and digital signals, sampling frequency, and samples. It explains how sampling works by taking regular measurements of a continuous signal's amplitude over time. This converts it into a discrete-time signal. It discusses applications of sampling like audio sampling, where signals are typically sampled above 20 kHz. It also discusses video sampling rates and speech sampling rates. The document contains examples and diagrams to illustrate these concepts.
Design of Scalable FFT architecture for Advanced Wireless Communication Stand...IOSRJECE
Now a day’s numerous wireless communication standards have raised additional stringent requirements on each throughput and flexibility for FFT computation. Advanced wireless systems support multiple standards to satisfy the demands of user application necessities. A wireless system whereas supporting multiple standards should also satisfy performance necessities of these supported standards. Meeting performance requirements of multiple standards is a challenge while designing a system. Fast Fourier transformations, a kernel processing task in communication systems, are studied intensively for efficient software and hardware implementations. To design an efficient system, it's necessary to efficiently design its performance critical component. each system must meet stringent design parameters like high speed, low power, low area, low cost, high flexibility and high scalability, designing FFT processor to support multiple wireless standards whereas meeting the above such performance necessities is a difficult task. This paper proposed a highly efficient scalable architecture, software tools design, and design implementation. The reconstruction of the FFT computation flow is design into a scalable structure. The FFT can be easily expanded for any-point FFT computation. The various parameters satisfied the conditions, gives proper and efficient outputs as compare to other platforms.
Data Compression using Multiple Transformation Techniques for Audio Applicati...iosrjce
IOSR Journal of Computer Engineering (IOSR-JCE) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of computer engineering and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications in computer technology. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
This document presents a comparative study of denoising 1-D data using wavelet transform. It studies the impact of different levels of decomposition and thresholding criteria (hard or soft) on output signal-to-noise ratio and mean square error when denoising four synthetic signals (blocks, bumps, doppler, heavy sine) corrupted with white noise using discrete wavelet transform. The results show that for blocks and bumps signals, soft thresholding produced higher output SNR and lower mean square error compared to hard thresholding. Higher levels of decomposition also led to better denoising for blocks but not for bumps.
Design of dfe based mimo communication system for mobile moving with high vel...Made Artha
The document discusses the design of a decision feedback equalizer (DFE) based multiple-input multiple-output (MIMO) communication system for mobile receivers moving at high velocities of up to 250km/hr. It analyzes the time dispersive and frequency dispersive effects of fading channels on signals. A DFE is proposed whose weights are periodically updated using the least mean squares (LMS) algorithm based on statistical channel parameters to combat the effects of fading. Simulation results show that the proposed MIMO system with a DFE achieves bit error rates below 10-3 at signal-to-noise ratios of 4dB and 10-4 at 6dB, even when the receiver is moving at 250km/hr.
International Journal of Engineering Research and Development (IJERD)IJERD Editor
journal publishing, how to publish research paper, Call For research paper, international journal, publishing a paper, IJERD, journal of science and technology, how to get a research paper published, publishing a paper, publishing of journal, publishing of research paper, reserach and review articles, IJERD Journal, How to publish your research paper, publish research paper, open access engineering journal, Engineering journal, Mathemetics journal, Physics journal, Chemistry journal, Computer Engineering, Computer Science journal, how to submit your paper, peer reviw journal, indexed journal, reserach and review articles, engineering journal, www.ijerd.com, research journals,
yahoo journals, bing journals, International Journal of Engineering Research and Development, google journals, hard copy of journal
AN OVERVIEW OF PEAK-TO-AVERAGE POWER RATIO REDUCTION TECHNIQUES FOR OFDM SIGNALSijmnct
OFDM (Orthogonal Frequency Division Multiplexing) has been widely adopted for high data rate wireless
communication systems due to its advantages such as extraordinary spectral efficiency, robustness to
channel fading and better QoS (Quality of Service) performance for multiple users. However, some
challenging issues are still unresolved in OFDM systems. One of the issues is the high PAPR (peak-toaverage
power ratio), which results in nonlinearity in power amplifiers, and causes out of band radiation
and in band distortion. This paper reviews some conventional PAPR reduction techniques and their
modifications to achieve better PAPR performance. Advantages and disadvantages of each technique are
discussed in detail. And comparisons between different techniques are also presented. Finally, this paper
makes a prospect forecast about the direction for further researches in the area of PAPR reduction for
OFDM signals
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
This document presents a sphere decoding algorithm for MIMO wireless systems. It begins with an abstract that introduces MIMO and sphere decoding. It then provides background on various receiver algorithms used for MIMO, including zero forcing, minimum mean square error, and maximum likelihood receivers. The key aspects of sphere decoding are discussed, including setting the initial radius and reducing the radius. A proposed sphere decoding method is presented that aims to find the transmitted signal vector with minimum complexity. Simulation results show that sphere decoding achieves near maximum likelihood performance while reducing complexity compared to other decoders.
Fast Fourier Transform (FFT) is an algorithm that divides a signal into its frequency components, with each component being a sinusoidal oscillation with its own amplitude and phase. An FFT rapidly computes the Discrete Fourier Transform (DFT) by factorizing the DFT matrix, reducing the complexity from O(n2) to O(n log n). FFT is widely used for applications like filtering, encoding, and solving difference equations. There are two main types of FFT analysis: the discrete Fourier transform, which transforms a sequence into frequencies, and the inverse FFT, which transforms frequencies back into a sequence. FFT analysis is useful for measuring signal frequencies but requires adequate sampling to avoid aliasing lower frequencies as higher ones.
Implementation Cost Analysis of the Interpolator for the Wimax Technologyiosrjce
The design of the multirate filter (programmable) has been proposed which can be used in digital
transceivers that meets 802.16d/e (wimax) standard in the wireless communication system. Wimax is a
technology emerging in the wireless communication system in order to increase the broadband wireless internet
access. As there is wide spread need of the digital representation of the signal for the transmission and storage
which create the challenges in DSP [1]. In this paper, analysis of the implementation cost of interpolator for the
wimax technology, and cost of interpolator is analyzed on the basis of number of adders and multiplier. The
Filters are designed using the FDA (filters design and analysis) tool in MATLAB.
Performance Analysis and Simulation of Decimator for Multirate ApplicationsIJEEE
1) The document presents the design and simulation of a decimator for multirate digital signal processing applications.
2) A decimator with different filter orders was designed using MATLAB to analyze performance based on ripple factor. Higher filter orders resulted in lower ripple factors but increased implementation costs.
3) A decimator with an order of 64 had the lowest ripple factor of 60% compared to orders of 32 and 16, though it had a higher implementation cost due to increased hardware requirements like multipliers and adders.
Implementation of adaptive stft algorithm for lfm signalseSAT Journals
Abstract
Normally Time-Frequency analysis is done by sliding a window through the time domain data and computing the Fourier
Transform of the data within the window. The choice of the window length determines whether specular or resonant information
will be emphasized. A narrow window will isolate specular reflections but will not be wide enough to accommodate the slowly
varying global resonances; a wide window cannot temporally separate resonance and specular information. So we will adapt
window length according to changes in frequencies. In this case we are realizing the specifications of Linear Frequency
Modulation (LFM) signal.
Index Terms—LFM, FFT, DFT, STFT and ASTFT.
Performance Analysis of Fractional Sample Rate Converter Using Audio Applicat...iosrjce
Fractional rate converters which are generally used for many applications with different frequencies
and are an essential part of communication systems. In this paper fractional rate converter with use of both
FIR and Nyquist FIR have been compared and analyzed. Its implementation can be easily found in the
developing communication systems, but here results are taken for audio applications. The proposed design and
analysis have been developed with the help of MATLAB with order 50 for FIR and 71 for Nyquist, sampling
frequency 48000Hz. The filters are then interpolated by an interpolation factor 2 and decimated by a decimation
factor of 3. The cost implementation of both has been taken into consideration and a result is drawn which
concludes that fractional rate converter for Nyquist FIR filter much more cost effective as compared to the
fractional rate converter for FIR filter
This document outlines the course details for a digital signal processing course. The main goal of the course is to design digital linear time-invariant filters that are widely used in applications such as audio, communications, radar, and biomedical engineering. Topics that will be covered include sampling of continuous-time signals, discrete-time signals and systems, the z-transform, filter design techniques, discrete Fourier transforms, and applications of digital signal processing. Students will be evaluated based on midterm and final exams, quizzes, assignments, and a project.
Improvement of minimum tracking in Minimum Statistics noise estimation methodCSCJournals
Noise spectrum estimation is a fundamental component of speech enhancement and speech recognition systems. In this paper we propose a new method for minimum tracking in Minimum Statistics (MS) noise estimation method. This noise estimation algorithm is proposed for highly nonstationary noise environments. This was confirmed with formal listening tests which indicated that the proposed noise estimation algorithm when integrated in speech enhancement was preferred over other noise estimation algorithms.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
Investigation and Analysis of SNR Estimation in OFDM systemIOSR Journals
Estimation of signal to noise ratio (SNR) of received signal and to transmit the signal effectively for
the modern communication system. The performance of existing non-data-aided (NDA) SNR estimation methods
are substantially degraded for high level modulation scheme such as M-ary amplitude and phase shift keying
(APSK) or quadrature amplitude modulation (QAM).In this paper SNR estimation proposed method which uses
zero point auto-correlation of received signal per block and auto/cross- correlation of decision feedback signal
in orthogonal frequency division multiplexing (OFDM) system. Proposed method can be studied into two types;
Type 1 can estimate SNR by zero point auto-correlation of decision feedback signal based on the second
moment property. Type 2 uses both zero point auto-correlation and cross-correlation based on the fourth
moment property. In block-by-block reception of OFDM system, these two SNR estimation methods can be
possible for the practical implementation due to correlation based the estimation method and they show more
stable estimation performance than the earlier SNR estimation methods.
This document summarizes a presentation on multirate digital signal processing. Multirate systems involve processing signals at different sampling rates, using operations like decimation to lower the sampling rate and interpolation to increase it. Decimation involves downsampling by discarding samples, while interpolation involves upsampling by inserting zeros. These operations are used for applications like sampling rate conversion, audio/video encoding, and communications systems. Key aspects of multirate signal processing discussed include anti-alias filtering, sampling rate conversion using cascaded decimation and interpolation, and choosing optimal filter designs.
An Efficient Data Communication Using Conventional CodesIJERA Editor
The BER performance of conventional FFT-OFDM system is compared with DWT-OFDM system and DCT-OFDM system in an AWGN environment and Saleh-Valenzuela (SV) channel model at 60 GHz. Several wavelets such as Haar, Daubechies, Symlet, biorthogonal are considered. The BER is calculated for signaling format BPSK and the performance is analyzed at 60 GHz. Simulation results show that DCT based scheme yields the lowest average bit error rate. While out of all wavelet mother used Haar and Daubechies wavelet based scheme yields lower BER than FFT-OFDM for an AWGN channel. But it may include the implementation of forward error correction techniques such as convolution codes. An efficient channel estimation algorithm may be included for performance evaluation of DCT-OFDM and DWT- OFDM working at 60 GHz band. We introduce the Interfacing Techniques for Accessing data transfer data delivery. By using our approach we are increasing the efficiency of the data communication.
Amin Sabri is a Chief Financial Officer with over 15 years of experience in financial analysis, reporting, forecasting, and operations management. He has held CFO and finance director roles at companies in Jordan and Saudi Arabia. Sabri has expertise in accounting, financial planning, cost analysis, and ensuring regulatory compliance. He is skilled in developing strategies, implementing best practices, and collaborating cross-functionally to achieve business and financial objectives.
This document discusses open educational resources (OER) including pros and cons. It defines OER as courses, materials, and techniques that can be freely used and adapted. Benefits include reducing costs, allowing customization for student interests, and sharing knowledge worldwide. However, some challenges are that instructors may not be familiar with new formats and adapting content across languages and technologies can be difficult. The document also outlines different creative commons licenses and their usage permissions as well as issues like maintaining quality and providing proper attribution when content is shared and revised.
Data Compression using Multiple Transformation Techniques for Audio Applicati...iosrjce
IOSR Journal of Computer Engineering (IOSR-JCE) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of computer engineering and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications in computer technology. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
This document presents a comparative study of denoising 1-D data using wavelet transform. It studies the impact of different levels of decomposition and thresholding criteria (hard or soft) on output signal-to-noise ratio and mean square error when denoising four synthetic signals (blocks, bumps, doppler, heavy sine) corrupted with white noise using discrete wavelet transform. The results show that for blocks and bumps signals, soft thresholding produced higher output SNR and lower mean square error compared to hard thresholding. Higher levels of decomposition also led to better denoising for blocks but not for bumps.
Design of dfe based mimo communication system for mobile moving with high vel...Made Artha
The document discusses the design of a decision feedback equalizer (DFE) based multiple-input multiple-output (MIMO) communication system for mobile receivers moving at high velocities of up to 250km/hr. It analyzes the time dispersive and frequency dispersive effects of fading channels on signals. A DFE is proposed whose weights are periodically updated using the least mean squares (LMS) algorithm based on statistical channel parameters to combat the effects of fading. Simulation results show that the proposed MIMO system with a DFE achieves bit error rates below 10-3 at signal-to-noise ratios of 4dB and 10-4 at 6dB, even when the receiver is moving at 250km/hr.
International Journal of Engineering Research and Development (IJERD)IJERD Editor
journal publishing, how to publish research paper, Call For research paper, international journal, publishing a paper, IJERD, journal of science and technology, how to get a research paper published, publishing a paper, publishing of journal, publishing of research paper, reserach and review articles, IJERD Journal, How to publish your research paper, publish research paper, open access engineering journal, Engineering journal, Mathemetics journal, Physics journal, Chemistry journal, Computer Engineering, Computer Science journal, how to submit your paper, peer reviw journal, indexed journal, reserach and review articles, engineering journal, www.ijerd.com, research journals,
yahoo journals, bing journals, International Journal of Engineering Research and Development, google journals, hard copy of journal
AN OVERVIEW OF PEAK-TO-AVERAGE POWER RATIO REDUCTION TECHNIQUES FOR OFDM SIGNALSijmnct
OFDM (Orthogonal Frequency Division Multiplexing) has been widely adopted for high data rate wireless
communication systems due to its advantages such as extraordinary spectral efficiency, robustness to
channel fading and better QoS (Quality of Service) performance for multiple users. However, some
challenging issues are still unresolved in OFDM systems. One of the issues is the high PAPR (peak-toaverage
power ratio), which results in nonlinearity in power amplifiers, and causes out of band radiation
and in band distortion. This paper reviews some conventional PAPR reduction techniques and their
modifications to achieve better PAPR performance. Advantages and disadvantages of each technique are
discussed in detail. And comparisons between different techniques are also presented. Finally, this paper
makes a prospect forecast about the direction for further researches in the area of PAPR reduction for
OFDM signals
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
This document presents a sphere decoding algorithm for MIMO wireless systems. It begins with an abstract that introduces MIMO and sphere decoding. It then provides background on various receiver algorithms used for MIMO, including zero forcing, minimum mean square error, and maximum likelihood receivers. The key aspects of sphere decoding are discussed, including setting the initial radius and reducing the radius. A proposed sphere decoding method is presented that aims to find the transmitted signal vector with minimum complexity. Simulation results show that sphere decoding achieves near maximum likelihood performance while reducing complexity compared to other decoders.
Fast Fourier Transform (FFT) is an algorithm that divides a signal into its frequency components, with each component being a sinusoidal oscillation with its own amplitude and phase. An FFT rapidly computes the Discrete Fourier Transform (DFT) by factorizing the DFT matrix, reducing the complexity from O(n2) to O(n log n). FFT is widely used for applications like filtering, encoding, and solving difference equations. There are two main types of FFT analysis: the discrete Fourier transform, which transforms a sequence into frequencies, and the inverse FFT, which transforms frequencies back into a sequence. FFT analysis is useful for measuring signal frequencies but requires adequate sampling to avoid aliasing lower frequencies as higher ones.
Implementation Cost Analysis of the Interpolator for the Wimax Technologyiosrjce
The design of the multirate filter (programmable) has been proposed which can be used in digital
transceivers that meets 802.16d/e (wimax) standard in the wireless communication system. Wimax is a
technology emerging in the wireless communication system in order to increase the broadband wireless internet
access. As there is wide spread need of the digital representation of the signal for the transmission and storage
which create the challenges in DSP [1]. In this paper, analysis of the implementation cost of interpolator for the
wimax technology, and cost of interpolator is analyzed on the basis of number of adders and multiplier. The
Filters are designed using the FDA (filters design and analysis) tool in MATLAB.
Performance Analysis and Simulation of Decimator for Multirate ApplicationsIJEEE
1) The document presents the design and simulation of a decimator for multirate digital signal processing applications.
2) A decimator with different filter orders was designed using MATLAB to analyze performance based on ripple factor. Higher filter orders resulted in lower ripple factors but increased implementation costs.
3) A decimator with an order of 64 had the lowest ripple factor of 60% compared to orders of 32 and 16, though it had a higher implementation cost due to increased hardware requirements like multipliers and adders.
Implementation of adaptive stft algorithm for lfm signalseSAT Journals
Abstract
Normally Time-Frequency analysis is done by sliding a window through the time domain data and computing the Fourier
Transform of the data within the window. The choice of the window length determines whether specular or resonant information
will be emphasized. A narrow window will isolate specular reflections but will not be wide enough to accommodate the slowly
varying global resonances; a wide window cannot temporally separate resonance and specular information. So we will adapt
window length according to changes in frequencies. In this case we are realizing the specifications of Linear Frequency
Modulation (LFM) signal.
Index Terms—LFM, FFT, DFT, STFT and ASTFT.
Performance Analysis of Fractional Sample Rate Converter Using Audio Applicat...iosrjce
Fractional rate converters which are generally used for many applications with different frequencies
and are an essential part of communication systems. In this paper fractional rate converter with use of both
FIR and Nyquist FIR have been compared and analyzed. Its implementation can be easily found in the
developing communication systems, but here results are taken for audio applications. The proposed design and
analysis have been developed with the help of MATLAB with order 50 for FIR and 71 for Nyquist, sampling
frequency 48000Hz. The filters are then interpolated by an interpolation factor 2 and decimated by a decimation
factor of 3. The cost implementation of both has been taken into consideration and a result is drawn which
concludes that fractional rate converter for Nyquist FIR filter much more cost effective as compared to the
fractional rate converter for FIR filter
This document outlines the course details for a digital signal processing course. The main goal of the course is to design digital linear time-invariant filters that are widely used in applications such as audio, communications, radar, and biomedical engineering. Topics that will be covered include sampling of continuous-time signals, discrete-time signals and systems, the z-transform, filter design techniques, discrete Fourier transforms, and applications of digital signal processing. Students will be evaluated based on midterm and final exams, quizzes, assignments, and a project.
Improvement of minimum tracking in Minimum Statistics noise estimation methodCSCJournals
Noise spectrum estimation is a fundamental component of speech enhancement and speech recognition systems. In this paper we propose a new method for minimum tracking in Minimum Statistics (MS) noise estimation method. This noise estimation algorithm is proposed for highly nonstationary noise environments. This was confirmed with formal listening tests which indicated that the proposed noise estimation algorithm when integrated in speech enhancement was preferred over other noise estimation algorithms.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
Investigation and Analysis of SNR Estimation in OFDM systemIOSR Journals
Estimation of signal to noise ratio (SNR) of received signal and to transmit the signal effectively for
the modern communication system. The performance of existing non-data-aided (NDA) SNR estimation methods
are substantially degraded for high level modulation scheme such as M-ary amplitude and phase shift keying
(APSK) or quadrature amplitude modulation (QAM).In this paper SNR estimation proposed method which uses
zero point auto-correlation of received signal per block and auto/cross- correlation of decision feedback signal
in orthogonal frequency division multiplexing (OFDM) system. Proposed method can be studied into two types;
Type 1 can estimate SNR by zero point auto-correlation of decision feedback signal based on the second
moment property. Type 2 uses both zero point auto-correlation and cross-correlation based on the fourth
moment property. In block-by-block reception of OFDM system, these two SNR estimation methods can be
possible for the practical implementation due to correlation based the estimation method and they show more
stable estimation performance than the earlier SNR estimation methods.
This document summarizes a presentation on multirate digital signal processing. Multirate systems involve processing signals at different sampling rates, using operations like decimation to lower the sampling rate and interpolation to increase it. Decimation involves downsampling by discarding samples, while interpolation involves upsampling by inserting zeros. These operations are used for applications like sampling rate conversion, audio/video encoding, and communications systems. Key aspects of multirate signal processing discussed include anti-alias filtering, sampling rate conversion using cascaded decimation and interpolation, and choosing optimal filter designs.
An Efficient Data Communication Using Conventional CodesIJERA Editor
The BER performance of conventional FFT-OFDM system is compared with DWT-OFDM system and DCT-OFDM system in an AWGN environment and Saleh-Valenzuela (SV) channel model at 60 GHz. Several wavelets such as Haar, Daubechies, Symlet, biorthogonal are considered. The BER is calculated for signaling format BPSK and the performance is analyzed at 60 GHz. Simulation results show that DCT based scheme yields the lowest average bit error rate. While out of all wavelet mother used Haar and Daubechies wavelet based scheme yields lower BER than FFT-OFDM for an AWGN channel. But it may include the implementation of forward error correction techniques such as convolution codes. An efficient channel estimation algorithm may be included for performance evaluation of DCT-OFDM and DWT- OFDM working at 60 GHz band. We introduce the Interfacing Techniques for Accessing data transfer data delivery. By using our approach we are increasing the efficiency of the data communication.
Amin Sabri is a Chief Financial Officer with over 15 years of experience in financial analysis, reporting, forecasting, and operations management. He has held CFO and finance director roles at companies in Jordan and Saudi Arabia. Sabri has expertise in accounting, financial planning, cost analysis, and ensuring regulatory compliance. He is skilled in developing strategies, implementing best practices, and collaborating cross-functionally to achieve business and financial objectives.
This document discusses open educational resources (OER) including pros and cons. It defines OER as courses, materials, and techniques that can be freely used and adapted. Benefits include reducing costs, allowing customization for student interests, and sharing knowledge worldwide. However, some challenges are that instructors may not be familiar with new formats and adapting content across languages and technologies can be difficult. The document also outlines different creative commons licenses and their usage permissions as well as issues like maintaining quality and providing proper attribution when content is shared and revised.
This document provides a summary of Yaser Hijazi's CV. It outlines his professional experience as Managing Director and General Manager of several food distribution companies in Jordan from 1999 to the present. It also lists his education, languages, training courses, skills, and contact information. Overall, the CV shows that Yaser Hijazi has over 20 years of experience in senior management roles in the FMCG industry in Jordan, with a focus on sales, marketing, business strategy, and operations.
Regional Access Summit in Kiev through the eyes of Access teachers from Moldova Olga Morozan
The document summarizes the ACCESS SUMMIT that was held in Kyiv, Ukraine from October 2-4, 2013. Students and teachers from Armenia, Azerbaijan, Georgia, Moldova, and Ukraine attended to learn about community service projects. The summit included sessions on social entrepreneurship, project design, global citizenship, and community problems. Students developed plans to address issues in their home countries. The experience encouraged collaboration between the groups and sharing of ideas online. The summit concluded with an awards ceremony and discussions about implementing community projects back home.
The document discusses the color scheme and design elements used across a movie poster, trailer, and magazine. A black and red color scheme is used to make the title and main character stand out and link the three pieces together. Black and white is also used to create a sense of danger and intrigue. The main character is prominently featured in all three works to emphasize his importance to the narrative. Release date and cast information are also consistently included to engage and inform audiences. The coordinated design is intended to present the works as part of a cohesive promotional campaign.
The document discusses how language varies based on social context and relationships between speakers. It covers topics like speech accommodation theory, how speakers converge or diverge based on their audience, and the influence of social class and culture on language. The concept of communicative competence is also introduced, which includes grammatical, discourse, sociolinguistic, and strategic competence that allow people to communicate effectively in different situations.
Access project Grigoriopol: Colorful town: Make your world better!Olga Morozan
A team conducted surveys through questionnaires with 50 people from two communities to get opinions on proposed street and body painting changes to improve the town. The surveys found that people agreed painting would make the town less "gray" and improve moods. The team then organized a body painting event with school children who enjoyed participating. They obtained art supplies and with help from experts and community members, painted murals on the walls of two schools. Follow-up surveys found participants were positive about the beautification project and impressed by the events.
El documento presenta un resumen de las principales corrientes económicas a lo largo de la historia, incluyendo el mercantilismo, la fisiocracia, la escuela clásica, la escuela marxista, la escuela neoclásica y la escuela keynesiana. Describe los principales pensadores, teorías, actividades económicas y la relación con el estado de cada corriente.
El documento describe la constitución del cuerpo colegiado del Centro de Bachillerato Tecnológico Timilpan. Se designan docentes representantes para diferentes áreas como matemáticas, ciencias naturales, ciencias sociales e idiomas. Se definen las funciones del cuerpo colegiado como promover la mejora continua de la educación mediante el análisis de problemas, la revisión de materiales y la participación en actividades de actualización y evaluación docente. Finalmente, los representantes y directivos firman el acta de constitución del cuerpo coleg
Este documento presenta un resumen del acta de una reunión de academia del Centro de Bachillerato Tecnológico de Timilpan. Los maestros discutieron varios problemas que afectan el rendimiento académico de los estudiantes, particularmente la falta de asistencia del 5-8% de los estudiantes diariamente. Se acordó implementar medidas como evitar el uso de celulares en clase, evaluar el trabajo diario en clase que no podrá recuperarse, y establecer consecuencias para estudiantes tardíos o que sal
Las principales corrientes económicas incluyen el mercantilismo, la fisiocracia, la economía clásica, la economía marxista, la economía neodásica y la economía keynesiana. Cada corriente se desarrolló en diferentes épocas y lugares, y se centró en aspectos como la naturaleza de la riqueza, la producción, la distribución y el papel del estado.
This document discusses how color is used to indicate space and depth. It outlines several spatial indicators used in color including size/scale, position/overlapping, linear perspective, value range/contrast, and detail. These spatial indicators are affected by color through value, intensity, complementary colors, warm/cool temperatures, and simultaneous contrast. Lighter, more intense colors tend to come forward while darker colors recede. The relationships between surrounding colors can cause optical illusions and affect how a color is perceived in space.
Performance Analysis of a SIMO-OFDM System Using Different Diversity Combinin...theijes
The motive of any wireless communication system is to reduce BER for the corresponding SNR. Through this OFDM based receiver diversity system we analyze BER for different diversity combining techniques such as EGC, MRC, SC in a rayliegh faded environment. This model serves two benefits: first noise limited system performance is improved by combating ISI through OFDM and second use of diversity combining which helps combat multipath fading. We also try to achieve an optimum trade-off between BER improvement and increase in number of receiver antennas. This is just to make less-complex receiver as it requires only one DFT processor.
Ber performance of ofdm with discrete wavelet transform for time dispersive c...eSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
An Adaptive Approach to Switching Coded Modulation in OFDM System Under AWGN ...ijsrd.com
In this paper we have studied the OFDM for different Quadrature amplitude modulation technique (QAM) The scatter plot and their output signal to noise ratio, dependent bit error rate variation is analyzed for every type of modulation in OFDM. After observing the BER for each SNR in the system, switching threshold range has been prepared and now system is ready to face the Adaptive coded modulation (ACM).The results shows the switching of modulation technique.
This document summarizes a research paper that proposes a new technique called Dummy Sequence Insertion (DSI) to reduce Peak-to-Average Power Ratio (PAPR) in OFDM systems. The technique inserts complementary dummy sequences into OFDM symbols to lower PAPR without transmitting side information. It partitions data subcarriers and adds Golay complementary sequences as dummy signals. The sequence is iteratively determined such that PAPR is reduced below a threshold. Simulation results show PAPR reduction of 5-6 dB with lower complexity than conventional Partial Transmit Sequence techniques since it requires fewer IFFT operations and no side information transmission. The technique simplifies power amplifier design while maintaining bandwidth efficiency.
International Journal of Engineering Research and Development (IJERD)IJERD Editor
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Iaetsd computational performances of ofdm usingIaetsd Iaetsd
This document discusses computational performances of OFDM using different pruned radix FFT algorithms. It introduces various FFT techniques such as radix-2, radix-4, radix-8, mixed radix and split radix. It then proposes an input zero traced radix DIF FFT pruning (IZTFFTP) algorithm to improve the efficiency of these FFT techniques when there are many zero valued inputs in OFDM. The computational complexity of implementing different radix FFTs with and without this pruning technique is calculated, and results show pruning provides more efficient OFDM performance in terms of reducing calculations.
Comparative evaluation of bit error rate for different ofdm subcarriers in ra...ijmnct
In the present situation, the expectation about the quality of signals in wireless communication is as high as possible. This quality issue is dependent upon the different communication parameters. One of the most important issues is to reduce the bit error rate (BER) to enhance the performance of the system. This paper provides a comparative analysis on the basis of this bit error rate. I have compared the BER for different number of subcarriers in OFDM system for BPSK modulation scheme. I have taken 6 varieties of data subcarriers to analyze this comparison. Here my target is to reach at the lowest level of BER for BPSK modulation. That is achieved at 2048 number of subcarriers.
Reducing the Peak to Average Power Ratio of Mimo-Ofdm SystemsIJCNCJournal
In this paper, we proposed a particle swarm optimization (PSO) based partial transmit sequence (PTS)
technique in order to achieve the lowest Peak-to-Average Power Ratio(PAPR) in Multiple Input Multiple
Output- Orthogonal Frequency Division Multiplexing (MIMO-OFDM) systems. Our approach consist of
applying the PSO based PTS on each antenna of the system in order to find the optimal phase factors,
which is a straightforward method to get the minimum PAPR in such a system. The simulation results
demonstrate that the PSO based PTS algorithm when applied to MIMO-OFDM systems with a wide range
of phase factors, tends to give a high performance. In addition, there is no need to increase the number of
particles of the PSO algorithm to enhance the performance of the system. As a result of this, the complexity
of finding the minimum PAPR is kept at a reasonable level.
Performance evaluation on the basis of bit error rate for different order of ...ijmnct
This document summarizes research evaluating the bit error rate (BER) for different modulation orders and subchannel lengths in an orthogonal frequency division multiplexing (OFDM) system. The research considers QPSK, 8-QAM, and 16-QAM modulation with 256, 512, and 4096 subchannels. Simulation results in MATLAB show that:
1) For 256 subchannels, QPSK modulation has the lowest BER across signal-to-noise ratio (SNR) values from 0-27dB.
2) BER increases with higher modulation orders (from QPSK to 16-QAM) for a given subchannel length.
3) The research provides a comparative analysis of BER performance in an OFDM system
The document discusses peak-to-average power ratio (PAPR) reduction techniques for orthogonal frequency division multiplexing (OFDM) systems. It analyzes the PAPR of discrete Hartley transform (DHT) precoded OFDM and compares it to discrete Fourier transform (DFT) precoded, Walsh-Hadamard transform (WHT) precoded, selected mapping (SLM) based, and conventional OFDM systems. Simulation results show that the WHT precoded OFDM system has the highest PAPR, while the DFT precoded OFDM system achieves zero PAPR. The document concludes that DFT precoding is the most effective technique for PAPR reduction analyzed.
Performance analysis of DWT based OFDM over FFT based OFDM and implementing o...VLSICS Design
Growth in technology has led to unprecedented demand for high speed architectures for complex signal processing applications. In 4G wireless communication systems, bandwidth is a precious commodity, and service providers are continuously met with the challenge of accommodating more users with in a limited allocated bandwidth. To increase data rate of wireless medium with higher performance, OFDM (orthogonal frequency division multiplexing) is used. Recently DWT (Discrete wavelet transforms) is adopted in place of FFT (Fast Fourier transform) for frequency translation. Modulation schemes such as 16-QAM, 32-QAM, 64-QAM and 128-QAM (Quadrature amplitude modulation) have been used in the developed OFDM system for both DWT and FFT based model. In this paper we propose a DWT-IDWT based OFDM transmitter and receiver that achieve better performance in terms SNR and BER for AWGN channel. It proves all the wavelet families better over the IFFT-FFT implementation. The OFDM model is developed using Simulink, various test cases have been considered to verify its performance. The DWTOFDM using Lifting Scheme architecture is implemented on FPGA optimizing hardware, speed & cost. The wavelet filter used for this is Daubechies (9, 7) with N=2. The RTL code is written in Verilog-HDL and simulated in Modelsim. The design is then synthesized in Xilinx and implemented on Virtex5 FPGA board and the results were validated using ChipScope.
Performance analysis of DWT based OFDM over FFT based OFDM and implementing o...VLSICS Design
Growth in technology has led to unprecedented demand for high speed architectures for complex signal processing applications. In 4G wireless communication systems, bandwidth is a precious commodity, and service providers are continuously met with the challenge of accommodating more users with in a limited allocated bandwidth. To increase data rate of wireless medium with higher performance, OFDM (orthogonal frequency division multiplexing) is used. Recently DWT (Discrete wavelet transforms) is adopted in place of FFT (Fast Fourier transform) for frequency translation. Modulation schemes such as 16-QAM, 32-QAM, 64-QAM and 128-QAM (Quadrature amplitude modulation) have been used in the developed OFDM system for both DWT and FFT based model. In this paper we propose a DWT-IDWT based OFDM transmitter and receiver that achieve better performance in terms SNR and BER for AWGN channel. It proves all the wavelet families better over the IFFT-FFT implementation. The OFDM model is developed using Simulink, various test cases have been considered to verify its performance. The DWTOFDM using Lifting Scheme architecture is implemented on FPGA optimizing hardware, speed & cost. The wavelet filter used for this is Daubechies (9, 7) with N=2. The RTL code is written in Verilog-HDL and simulated in Modelsim. The design is then synthesized in Xilinx and implemented on Virtex5 FPGA board and the results were validated using ChipScope.
This document discusses the partial transmit sequence (PTS) technique for reducing peak-to-average power ratio (PAPR) in orthogonal frequency division multiplexing (OFDM) systems. The PTS technique works by dividing the input data symbols into disjoint sub-blocks that are then phase rotated by selected phase factors to improve PAPR performance. Simulation results show that PTS achieves excellent PAPR reduction for OFDM signals but at the cost of an exhaustive search over all possible phase combinations, resulting in high computational complexity. The key advantage of PTS is good PAPR reduction performance, but its main drawback is increased complexity with larger numbers of sub-blocks.
Peak detection using wavelet transformIJCNCJournal
A new work based-wavelet transform is designed to overcome one of the main drawbacks that found in the
present new technologies. Orthogonal Frequency Division Multiplexing (OFDM)is proposed in the
literature to enhance the multimedia resolution. However, the high peak power (PAPR) values will obstruct
such achievements. Therefore, a new proposition is found in this work, making use of the wavelet
transforms methods, and it is divided into three main stages; de-noising stage, thresholding stage and then
the replacement stage.
In order to check the system stages validity; a mathematical model has been built and its checked after
using a MATLAB simulation. A simulated bit error rate (BER) achievement will be compared with our
previously published work, where an enhancement from 8×10-1 to be 5×10-1 is achieved. Moreover, these
results will be compared to the work found in the literature, where we have accomplished around 27%
PAPR extra reduction.
As a result, the BER performance has been improved for the same bandwidth occupancy. Moreover and
due to the de-noise stage, the verification rate has been improved to reach 81%. This is in addition to the
noise immunity enhancement.
Simulation Study and Performance Comparison of OFDM System with QPSK and BPSKpaperpublications3
Abstract: FDMA, TDMA and CDMA are the well-known multiplexing techniques used in wireless communication systems. While working with the wireless systems using these techniques various problems are encountered especially when a typical transmitted signal arrives at the receiver using various paths of different lengths. Since multiple versions of the signal interfere with each other, it becomes difficult to extract the original information. The use of orthogonal frequency division multiplexing (OFDM) technique provides better solution for the above mentioned problem. OFDM technique distributes the data over a large number of carriers that are spaced apart at precise frequencies. This spacing provides the "orthogonality", which prevents the demodulator from seeing frequencies other than their own. The benefits of OFDM are high spectral efficiency, resiliency of RF interference, and lower multi-path distortion. OFDM is a powerful modulation technique that is capable of high data rate and is able to eliminate ISI. Using MATLAB, simulation of OFDM was done with different modulation techniques using different transform techniques. The digital modulation schemes such as BPSK and QPSK were selected to assess the performance of the designed OFDM system.
A Hybrid PAPR Reduction Scheme for OFDM System ijmnct
Orthogonal frequency division multiplexing (OFDM) i
s considered as most efficient technique for future
wireless communication systems due to its higher sp
ectral bandwidth efficiency, robustness to frequenc
y
selective fading channels, etc. However, the succes
sful implementation of the OFDM system necessitates
several difficulties. The biggest disadvantage to w
ork with OFDM system is its high peak-to-average po
wer
ratio PAPR leadsto severe inter carrier interferenc
e, out-of-band radiation, and poor bit error rate
performance due to the nonlinearity of the high pow
er amplifier. In this paper, a novel hybrid techniq
ue is
proposed to reduce PAPR further and comparison has
been done with conventional techniques as well.
Simulated results are presentedconfirm theoretical
results.MATLAB 7.5 is used to simulate the results
for system parametersconsidered.
Designing and Performance Evaluation of 64 QAM OFDM SystemIOSR Journals
Abstract (11Bold) : — In this report, the performance analysis of 64 QAM-OFDM wireless communication
systems affected by AWGN in terms of Symbol Error Rate and Throughput is addressed. 64 QAM (64 ary
Quadrature Amplitude Modulation) is the one of the effective digital modulation technique as it is more power
efficient for larger values of M(64). The MATLAB script based model of the 64 QAM-OFDM system with
normal AWGN channel and Rayleigh fading channel has been made for study error performance and
throughput under different channel conditions. This simulated model maximizes the system throughput in the
presence of narrowband interference, while guaranteeing a SER below a predefined threshold. The SER
calculation is accomplished by means of modelling the decision variable at the receiver as a particular case of
quadratic form D in complex Gaussian random variables. Lastly comparative study of SER performance of 64
QAM-OFDM simulated & 64 QAM-OFDM theoretical under AWGN channel has been given. Also
performance of the system is given in terms of throughput (received bits/ofm symbol) is given in a plot for
different SNR. Keywords (11Bold) –64 QAM, BPSK, OFDM, PDF, SNR.
Designing and Performance Evaluation of 64 QAM OFDM SystemIOSR Journals
In this report, the performance analysis of 64 QAM-OFDM wireless communication
systems affected by AWGN in terms of Symbol Error Rate and Throughput is addressed. 64 QAM (64 ary
Quadrature Amplitude Modulation) is the one of the effective digital modulation technique as it is more power
efficient for larger values of M(64). The MATLAB script based model of the 64 QAM-OFDM system with
normal AWGN channel and Rayleigh fading channel has been made for study error performance and
throughput under different channel conditions. This simulated model maximizes the system throughput in the
presence of narrowband interference, while guaranteeing a SER below a predefined threshold. The SER
calculation is accomplished by means of modelling the decision variable at the receiver as a particular case of
quadratic form D in complex Gaussian random variables. Lastly comparative study of SER performance of 64
QAM-OFDM simulated & 64 QAM-OFDM theoretical under AWGN channel has been given. Also
performance of the system is given in terms of throughput (received bits/ofm symbol) is given in a plot for
different SNR
The several assets for high-speed data transmission over wireless uses the Orthogonal Frequency Division
Multiplexing (OFDM) as it is a multicarrier transmission scheme. A large number of narrow bandwidth carriers is
therefore adopted by the OFDM. Individually for an OFDM, each subcarrier is attenuated under the frequency-selective
and fast fading channel, therefore the resulting gain is high attenuation which leads to poor performance of all OFDM
subcarriers if the same fixed transmission scheme are used. Thus the main goal of the indicated paper is to grab an
understanding of the inequality between fixed & adaptive modulations schemes as the introduction of the adaptive
modulation. The need for the above system is to make use of the speaker's voice to check their character and control
approach to administrations, for example, voice dialing data administrations, voice send, and security control for secret
data. The performance of paperwork basically states that implementation of adaptive modulation is done into blocks of
adjacent subcarriers which is the result of dividing whole subcarriers. Therefore the equivalent modulation scheme which
is the calculation of average instantaneous signal to noise (SNR) is exercised to entire subcarriers of the equal block. The
OFDM system average bit error rate (BER) performance is observed here under fixed modulation and adaptive
modulation, and these modulation techniques are recorded by accepting the different inverse fast Fourier transforms
(IFFT) size and uncomplicated adaptive Quadrature amplitude modulation (QAM) strategy. The simulation in MATLAB
shows the results as the performance of fixed modulation is inferior to that of the BER performance of OFDM system
using adaptive modulation. The prospective adaptive modulation and coding Technique uses OFDM to manage the fixed
BER under changing the channel.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
Similar to Dwpt Based FFT and Its Application to SNR Estimation in OFDM Systems (20)
Walmart Business+ and Spark Good for Nonprofits.pdfTechSoup
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ISO/IEC 27001, ISO/IEC 42001, and GDPR: Best Practices for Implementation and...PECB
Denis is a dynamic and results-driven Chief Information Officer (CIO) with a distinguished career spanning information systems analysis and technical project management. With a proven track record of spearheading the design and delivery of cutting-edge Information Management solutions, he has consistently elevated business operations, streamlined reporting functions, and maximized process efficiency.
Certified as an ISO/IEC 27001: Information Security Management Systems (ISMS) Lead Implementer, Data Protection Officer, and Cyber Risks Analyst, Denis brings a heightened focus on data security, privacy, and cyber resilience to every endeavor.
His expertise extends across a diverse spectrum of reporting, database, and web development applications, underpinned by an exceptional grasp of data storage and virtualization technologies. His proficiency in application testing, database administration, and data cleansing ensures seamless execution of complex projects.
What sets Denis apart is his comprehensive understanding of Business and Systems Analysis technologies, honed through involvement in all phases of the Software Development Lifecycle (SDLC). From meticulous requirements gathering to precise analysis, innovative design, rigorous development, thorough testing, and successful implementation, he has consistently delivered exceptional results.
Throughout his career, he has taken on multifaceted roles, from leading technical project management teams to owning solutions that drive operational excellence. His conscientious and proactive approach is unwavering, whether he is working independently or collaboratively within a team. His ability to connect with colleagues on a personal level underscores his commitment to fostering a harmonious and productive workplace environment.
Date: May 29, 2024
Tags: Information Security, ISO/IEC 27001, ISO/IEC 42001, Artificial Intelligence, GDPR
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Main Java[All of the Base Concepts}.docxadhitya5119
This is part 1 of my Java Learning Journey. This Contains Custom methods, classes, constructors, packages, multithreading , try- catch block, finally block and more.
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Executive Directors Chat Leveraging AI for Diversity, Equity, and InclusionTechSoup
Let’s explore the intersection of technology and equity in the final session of our DEI series. Discover how AI tools, like ChatGPT, can be used to support and enhance your nonprofit's DEI initiatives. Participants will gain insights into practical AI applications and get tips for leveraging technology to advance their DEI goals.
This slide is special for master students (MIBS & MIFB) in UUM. Also useful for readers who are interested in the topic of contemporary Islamic banking.
A review of the growth of the Israel Genealogy Research Association Database Collection for the last 12 months. Our collection is now passed the 3 million mark and still growing. See which archives have contributed the most. See the different types of records we have, and which years have had records added. You can also see what we have for the future.
Exploiting Artificial Intelligence for Empowering Researchers and Faculty, In...Dr. Vinod Kumar Kanvaria
Exploiting Artificial Intelligence for Empowering Researchers and Faculty,
International FDP on Fundamentals of Research in Social Sciences
at Integral University, Lucknow, 06.06.2024
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How to Build a Module in Odoo 17 Using the Scaffold MethodCeline George
Odoo provides an option for creating a module by using a single line command. By using this command the user can make a whole structure of a module. It is very easy for a beginner to make a module. There is no need to make each file manually. This slide will show how to create a module using the scaffold method.
LAND USE LAND COVER AND NDVI OF MIRZAPUR DISTRICT, UPRAHUL
This Dissertation explores the particular circumstances of Mirzapur, a region located in the
core of India. Mirzapur, with its varied terrains and abundant biodiversity, offers an optimal
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advanced technologies such as GIS (Geographic Information Systems) and Remote sensing to
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The complex relationship between human activities and the environment has been the focus
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accelerated due to factors such as agriculture and urbanization. Information regarding land use and
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Accurate understanding of land use and cover is imperative for the development planning
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9
Changes in vegetation cover refer to variations in the distribution, composition, and overall
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occur natural.
it describes the bony anatomy including the femoral head , acetabulum, labrum . also discusses the capsule , ligaments . muscle that act on the hip joint and the range of motion are outlined. factors affecting hip joint stability and weight transmission through the joint are summarized.
How to Make a Field Mandatory in Odoo 17Celine George
In Odoo, making a field required can be done through both Python code and XML views. When you set the required attribute to True in Python code, it makes the field required across all views where it's used. Conversely, when you set the required attribute in XML views, it makes the field required only in the context of that particular view.
Dwpt Based FFT and Its Application to SNR Estimation in OFDM Systems
1. Rana Shahid Manzoor, Regina Gani, Varun Jeoti, Nidal Kamel & Muhammad Asif
Signal Processing: An International Journal (SPIJ)Volume (3) : Issue (2) 22
Dwpt Based FFT and ITS Application to SNR Estimation in OFDM
Systems
Rana Shahid Manzoor engr.shahid@gmail.com
Regina Gani reginagani@gmail.com
Varun Jeoti varun_jeoti@petronas.com.my
Nidal Kamel nidalkamel@petronas.com.my
Muhammad Asif asf_kh@yahoo.com
Electrical & Electronic Engineering Department,
Universiti Teknologi PETRONAS (UTP),
Bandar Seri Iskandar, Tronoh, 31750, Malaysia
ABSTRACT
In this paper, wavelet packet (WP) based FFT and its application to SNR
estimation is proposed. OFDM systems demodulate data using FFT. The
proposed solution computes the exact FFT using WP and its computational
complexity is of the same order as FFT, i.e. O (N log2 N). SNR estimation is done
inside wavelet packet based FFT block unlike other SNR estimators which
perform SNR estimation after FFT. The data, so analyzed using wavelet packets,
is used to perform SNR estimation in colored noise. The proposed estimator
takes into consideration the different noise power levels of the colored noise over
the OFDM sub-carriers. The OFDM band is divided into several sub-bands using
wavelet packet and noise in each sub-band is considered white. The second-
order statistics of the transmitted OFDM preamble are calculated in each sub-
band and the power of the noise is estimated. The proposed estimator is
compared with Reddy’s estimator for colored noise in terms of mean squared
error (MSE).
Keywords: SNR, Noise power estimation, Wavelet Packet, Adaptive modulation, OFDM.
1. INTRODUCTION
Fourth Generation wireless and mobile systems characterized by broadband wireless systems
are currently the focus of research and development among the researchers everywhere. The
broadband wireless systems favor the use of orthogonal frequency division multiplexing (OFDM)
modulation that allows high data-rate communication. A major advantage of OFDM systems is its
ability to divide the input high rate data stream into many low-rate streams that are transmitted in
parallel. Doing so increases the symbol duration and reduces the intersymbol interference over
2. Rana Shahid Manzoor, Regina Gani, Varun Jeoti, Nidal Kamel & Muhammad Asif
Signal Processing: An International Journal (SPIJ)Volume (3) : Issue (2) 23
frequency-selective fading channels. This and other features of equivalent importance have
motivated the adoption of OFDM as a standard for several applications such as digital video
broadcasting (DVB) and broadband indoor wireless local area networks, broadband wireless
metropolitan area networks and many others.
In order to exploit all these advantages and maximize the performance of OFDM systems;
channel state information (CSI) plays a very important role. Signal-to-noise ratio (SNR) is a
quantity that gives a comprehensive measure of CSI for each frame. An on-line SNR estimator
thus provides the knowledge to decide whether a transition to higher bit rates would be favorable
or not.
Signal-to-noise ratio (SNR) is defined as the ratio of the desired signal power to the noise power.
Noise variance, and hence, SNR estimates of the received signal are very important parameters
for the channel quality control in communication systems [1]. The search for a good SNR
estimation technique is motivated by the fact that various algorithms require knowledge of the
SNR for optimal performance. For instance, in OFDM systems, SNR estimation is used for power
control, adaptive coding and modulation, turbo decoding etc.
SNR estimation indicates the reliability of the link between the transmitter and receiver. In
adaptive system, SNR estimation is commonly used for measuring the quality of the channel and
accordingly changing the system parameters. For example, if the measured channel quality is
low, the transmitter may add some redundancy or complexity to the information bits (more
powerful coding), or reduce the modulation level (better Euclidean distance), or increase the
spreading rate (longer spreading code) for lower data rate transmission. Therefore, instead of
implementing fixed information rate for all levels of channel quality, variable rates of information
transfer can be used to maximize system resource utilization with high quality of user experience
[2].
Many SNR estimation algorithms have been suggested in the last ten years [1]-[6] and also
successfully implemented in OFDM systems using the pilot symbols [1,2,5]. Extracting pilots and
using them for SNR estimation is computationally complex. The essential requirement for an SNR
estimator in OFDM system is of low computational load. This is in order to minimize hardware
complexity as well as the computational time. This is the motivating factor for the pursuit of an
SNR estimator that does not require the manipulation of pilot symbols. SNR estimator, presented
in the past, performed SNR estimation using pilot symbols at the back-end of the receiver in the
OFDM system [2]. The SNR estimator presented in this paper performs SNR estimation inside
FFT and makes use of only one OFDM synchronization preamble. In many SNR estimation
techniques, noise is assumed to be uncorrelated or white. But, in wireless communication
systems, where noise is mainly caused by a strong interferer, noise is colored in nature.
According to best knowledge of authors, so far only Reddy’s estimator considered colored noise
scenario. Hence we use his work for the purpose of comparison in this paper. Reddy’s estimator
makes use of several OFDM symbols to perform SNR estimation; hence the computational
complexity of finding good estimates is very high. So there is enough interest to design an
efficient SNR estimator that is computationally simple.
OFDM demodulation uses discrete Fourier transform (DFT). An FFT (fast Fourier transform) is
used to demodulate data. In this paper a novel wavelet packet based FFT and its application to
SNR estimation is presented. The proposed solution computes the exact result, and its
computational complexity is same order of FFT, i.e. O (Nlog2 N).
The proposed SNR technique performs SNR estimation inside FFT unlike previous SNR
estimators. SNR estimator for the colored noise in OFDM system is proposed. The algorithm is
based on the two identical halves property of time synchronization preamble used in some OFDM
systems. The OFDM band is divided into several sub-bands using wavelet packet and noise in
each sub-band is considered white. The second-order statistics of the transmitted OFDM
preamble are calculated in each sub-band and the power noise is estimated. Therefore, the
3. Rana Shahid Manzoor, Regina Gani, Varun Jeoti, Nidal Kamel & Muhammad Asif
Signal Processing: An International Journal (SPIJ)Volume (3) : Issue (2) 24
proposed approach estimates both local (within smaller sets of subcarriers) and global (over all
sub-carriers) SNR values. The short term local estimates calculate the noise power variation
across OFDM sub-carriers. When the noise is white, the proposed algorithm works as good as
the conventional noise power estimation schemes, showing the generality of the proposed
method.
The remainder of the paper is organized as follows. In Section 2, the proposed wavelet packet
based FFT technique is presented. Section 3 provides the proposed SNR estimation. Section 4
describes the Reddy’ SNR estimator used for comparison with proposed SNR estimator. Section
5 presents simulation results and discussion. Section 6 concludes the paper.
2. PROPOSED WAVELET PACKET BASED FFT (DWPT-FFT)
The fundamental principle that the FFT relies on is that of decomposing the computation of the
discrete Fourier transform of a sequence of length N into successively smaller discrete Fourier
transforms of the even and odd parts. In the proposed method the even – odd separation is
replaced by wavelet packet decomposition.
The block diagram of proposed DWPT-FFT is shown in Figure 1. The idea is borrowed from Guo
[7]. Wavelet packet based FFT first performs Wavelet Packet decomposition, followed by reduced
size FFT and butterfly operation as shown in Figure1. This can be extended so that WP analysis
is 3 to 4 level analysis and FFT is N/4, N/8 or N/16 size FFT. Butterfly is appropriately designed.
Figure 1: Block diagram of DWPT-FFT
The wavelet packet based FFT (DWPT-FFT) is represented by equation 1:
[ ]N
2N
2N
2
N
2
N
2
N
2
N
N WP
F0
0F
DC
BA
F
=
/
/
(1)
where AN/2,BN/2,CN/2 and DN/2 are all diagonal matrices. In equation 1, the values on the
diagonal of AN/2 and CN/2 are the length-N DFT of ‘h’, the scaling filter coefficients, and the values
on the diagonal of BN/2 and DN/2 are the length-N DFT of ‘g’, the wavelet filter coefficients. The
factorization can be visualized as
Wavelet Packet N/2 FFT Butterfly
SNR Estimation
4. Rana Shahid Manzoor, Regina Gani, Varun Jeoti, Nidal Kamel & Muhammad Asif
Signal Processing: An International Journal (SPIJ)Volume (3) : Issue (2) 25
where we image the real part of DFT matrices, and the magnitude of the matrices for butterfly
operations and the one-scale DWPT using db3 wavelets. Clearly we can see that the twiddle
factors have non-unit magnitude.
The above factorization suggests a DWPT-FFT algorithm. The block Diagram of length 8
algorithm is shown in Figure 2. Following this, the high pass and the low pass DWPT outputs go
through separate length-4 DFT, then they are combined with butterfly operations.
Same procedure in Figure2 is iteratively applied to short length DFTs to get the full DWPT based
FFT algorithm where the twiddle factors are the frequency wavelet filters. The detail of butterfly
operations is shown in Figure 3 where ‘i’ belongs to {0,1,….N/2-1}.
Figure 2: Last stage of length 8 DWPT-FFT
Figure 3: Butterfly operation in DWPT-FFT
Figure 4: Two-scale discrete wavelet packet transforms
Length-4DFTLength-4DFT
1-Scalelength-8DWPT
AN/2 (i.i)
BN/2 (i.i)
CN/2 (i.i)
DN/2 (i.i)
5. Rana Shahid Manzoor, Regina Gani, Varun Jeoti, Nidal Kamel & Muhammad Asif
Signal Processing: An International Journal (SPIJ)Volume (3) : Issue (2) 26
Wavelet packet allows a finer and adjustable resolution of frequencies at high frequency. Input
data are first filtered by pair of filters h and g (low pass and high pass respectively) and then
down sampled. The same analysis is further iterated on both low and high frequency bands as
shown in Figure 4.
For the DWPT based FFT algorithm, the computational complexity is also O (N log2N). However,
the constant appears before N log2N depends on the wavelet filters used.
3. SNR ESTIMATION
Wavelet Packet analyzed data becomes available for SNR estimation inside FFT block as shown
in figure1. The synchronization OFDM preamble - the preamble which has two identical halves
property as shown in figure 5, is obtained by loading constellation points with a PN sequence
(Pseq) at even sub-carriers using equation 2 [9]:
(2)
where the factor of 2 is related to the 3 dB boost and '' k shows the sub-carriers index.
OFDM training/synchronization data of length ‘N’ is sent from the transmitter (Tx). To avoid
intersymbol interference (ISI), a cyclic prefix (CP) is added.
After removing cyclic prefix at receiver, OFDM data is divided into 2
n
sub-bands using periodic
wavelet packets where ‘n’ shows the number of levels. The length of each sub-band is
Nsub = N/2
n
. It inherits the two identical halves property of synchronization preamble. The noise in
each sub-band is considered white. The system’s parameters and the structure of wavelet packet
used for the simulations are calculated using [9] as shown in table 1.
Figure 5: OFDM training symbol with cyclic prefix.
3.1. SIGNAL POWER AND NOISE POWER ESTIMATION
The received signal in the k
th
sub band is rk (n) and it is expressed as,
)()()(
)()()(
nnnhns
nnnsnr
kkk
kkk
+∗=
+′=
(3)
The autocorrelation function of the received signal in kth sub-band, Rk
rr (m) has the following
relationship to the autocorrelation of the transmitted sub-band signal, Rk
s’s’ (m) and the noise,
Rk
nn(m):
)()()( '' mRmRmR k
nn
k
ss
k
rr += (4)
n321m
12mk0
2mkkP2
kP seq
even .....,,
)(.
)( =
+=
=
=
CP
1 N/2 N
6. Rana Shahid Manzoor, Regina Gani, Varun Jeoti, Nidal Kamel & Muhammad Asif
Signal Processing: An International Journal (SPIJ)Volume (3) : Issue (2) 27
where )()('' mRmR ssk
k
ss α= , kα is the attenuated channel power in the k
th
sub-band. Over
a small bandwidth of k
th
sub band, it is safe to assume that, even in frequency selective channels,
the attenuation is constant and equal to kα .
The noise in channel is modeled as additive white Gaussian noise, thus its autocorrelation
function can be expressed as
)()( 2
mmR nn δσ= (5)
where δ (m) is the discreet delta sequence and σ
2
is the power of noise.
A study of the OFDM signal shows that, as all the sub-carriers are present with equal power over
the signal bandwidth, the power spectrum of an OFDM signal is nearly white and hence its
autocorrelation is also given by
)()('' mmR kss δα= (6)
Hence, at zero lag, the autocorrelation contains both the signal power estimate and noise power
estimate indistinguishable from each other.
However, because of the identical halves nature of the preamble the autocorrelation also has
peaks where one half matches with other half on both sides of the zero delay. The autocorrelation
of the transmitted and received scale 5 sub-band signal at SNR = 7 dB are shown in figure 6(a)
and figure 6(b), respectively. It is clear that the autocorrelation values apart from the zero-offset
are unaffected by the AWGN, so one can find the signal and noise powers from the zero-lag
autocorrelation value ’L’.
Taking into consideration the autocorrelation values for L-Nsub/2 and L+Nsub/2 signal power is
given as
)2/(2 subrr NLR −=
∧
α (7)
Or
)2/(2 subrr NLR +=
∧
α (8)
Having obtained the power of signal in certain sub-band, noise power can be calculated using
equation 8.
∧
−= ασ )(ˆ 2
subrr LR
(9)
Finally we can find the SNR estimates in the sub-band by using equation (7 or 8) and equation
(9):
2
ˆ
ˆ
σ
α
∧
=RNS (10)
where RNS ˆ is the estimated value for SNR.
7. Rana Shahid Manzoor, Regina Gani, Varun Jeoti, Nidal Kamel & Muhammad Asif
Signal Processing: An International Journal (SPIJ)Volume (3) : Issue (2) 28
Figure 6: Autocorrelation plot of transmitted (a) and received (b) 5
th
band signal
4. REDDY’S SNR ESTIMATOR FOR COLORED NOISE
In this method channel estimation is performed in the first realization of the channel, using pilot
symbols and this estimate is used to estimate the signal noise power. The suggested method can
be used Additive White Gaussian Noise (AWGN) channel and for color dominated channel, in
which the noise power varies across the frequency spectrum [2].
The system model is described in the frequency domain, where a signal is transmitted to obtain
the estimated channel frequency response after which the instantaneous noise power mean
square is determined. The transmitted signal includes white noise which is added by the channel
of unknown amplitude. This is modeled in the frequency domain by the equation:
)()()()( kNkHkSkR mmmm += (11)
where
)( kS m = Transmitted signal
)( kR m = Received signal
)( kN m
= Channel white noise
8. Rana Shahid Manzoor, Regina Gani, Varun Jeoti, Nidal Kamel & Muhammad Asif
Signal Processing: An International Journal (SPIJ)Volume (3) : Issue (2) 29
The channel frequency response is estimated by transmitting preamble and performing division in
the frequency domain of the received signal by the transmitted signal. When performing the
division, the effect of noise is ignored. The pilot symbols are then used as the transmitted signal
and the received signal in the pilot sub-carriers is used for the received signal and the estimated
transfer function inserted in the equation to determine the noise power estimate. The noise power
estimation is found by finding the difference between the noisy received signal and the noiseless
signal.
22
)()()()( kHkSkRk mmmm
∧∧
−=σ (12)
The difference between the actual channel frequency response and the estimated is the
channel estimation error.
5. RESULTS AND DISCUSSIONS
In this section, we will first show that DWPT based FFT algorithm is able to compute FFT exactly.
Following that, we will present the performance results of proposed estimator designed using
wavelet packet based FFT. The results would include mean squared error of our estimation as
compared to that of Reddy’s.
The proposed DWPT-FFT computes the exact result. In order to show that the example of a chirp
signal is taken and its FFT computed both from DWPT based algorithm and discrete Fourier
transform (DFT) equation. The chirp signal is defined by Nenx
2nj
/)( π
= , and its FFT as
computed using DWPT and DFT are shown in figure 7.
Figure 7: FFT result with and without wavelet packet
9. Rana Shahid Manzoor, Regina Gani, Varun Jeoti, Nidal Kamel & Muhammad Asif
Signal Processing: An International Journal (SPIJ)Volume (3) : Issue (2) 30
This performance of our estimator is measured in terms of Mean Squared Error. To obtain these
results, OFDM system parameters given in Table 1 were chosen. The proposed SNR estimator is
compared with Reddy’s estimator for colored noise in OFDM systems. The parameters given in
Table 1 are same for both estimators except that for Reddy’s estimator 50 OFDM symbols are
used to perform SNR estimation.
SNR is varied from 1 dB to 14 dB for each sub-band and the mean-squared error (MSE) is
derived for the estimated SNR from 2000 trials according to the following formula
∑
=
−=
2000
1i
2
SNRiRNS
2000
1
MSE ))(ˆ( (13)
From figure 8 and figure 9 it is clear that the proposed estimator gives better performance in SNR
estimation as compared to Reddy estimator. It is observed that the proposed technique can
estimate local statistics of the noise power when the noise is colored.
Table 1: Parameters for the simulation
Ifft size 256
Sampling Frequency = F s .20MHz
Sub Carrier Spacing=
Ifft
Ff s=∆ 5
101×
Useful Symbol Time =
fT b ∆
= 1 5
101 −
×
CP Time = TGT bg *= where 41=G 6
105.2 −
×
OFDM Symbol Time = TTT gbs += 5
1025.1 −
×
TT ss *
4
5= (Because ¼ CP
makes the sampling faster by 5/4 times)
5
1056.1 −
×
16
s
sub
T
T = 7
108.9 −
×
Wavelet Packet Object Structure
Wavelet Decomposition Command : wpdec
Size of initial data : [1 320]
Order= 2
Deptth=: 4
Terminal nodes : [15 16 17 18 19 20 21 22
23 24 25 26 27 28 29 30]
--------------------------------------------------
Wavelet Name : Daubechies (db3) ,
Entropy Name : Shannon
10. Rana Shahid Manzoor, Regina Gani, Varun Jeoti, Nidal Kamel & Muhammad Asif
Signal Processing: An International Journal (SPIJ)Volume (3) : Issue (2) 31
Figure 8: MSE performance of the proposed technique
Figure 9: Actual SNR vs. Estimated SNR of colored noise
11. Rana Shahid Manzoor, Regina Gani, Varun Jeoti, Nidal Kamel & Muhammad Asif
Signal Processing: An International Journal (SPIJ)Volume (3) : Issue (2) 32
Complexity of proposed technique:
The proposed wavelet packet based FFT computes the exact result, and its computational
complexity is of the same order of FFT, i.e. )(log2 NO .
The proposed autocorrelation based SNR estimator inside FFT makes use of one OFDM
preamble so its complexity is
3
2~ N as compared to Reddy’ estimator which have complexity
3
50~ N (where 50 shows the number of OFDM symbols used to get better SNR estimates after
averaging over these OFDM symbols). The proposed estimator has relatively low computational
complexity because it makes use of only one OFDM preamble signal to find the SNR estimates.
The proposed estimator fulfills the criteria of a good SNR estimator because it is unbiased (i.e. it
exhibits the smallest bias) and has the least variance of SNR estimates as seen from mean
squared error diagrams..
6. CONCLUSION
In this paper, an algorithm to compute FFT using discrete wavelet packets is developed and
applied to the problem of SNR estimation in OFDM systems inside FFT. Also, the technique is
extended to SNR estimation under colored noise where the variation of the noise power across
OFDM sub-carriers is allowed. The second-order statistics of the transmitted OFDM preamble are
calculated in each sub-band and the noise power is estimated. Therefore, the proposed approach
estimates both local (within smaller sets of subcarriers) and global (over all sub-carriers) SNR
values. The short term local estimates calculate the noise power variation across OFDM sub -
carriers. The results show that the proposed estimator performs better than other conventional
methods. Complexity to find SNR estimates is much lower because our estimator makes use of
only one OFDM preamble signal. This estimator fulfills the criteria of a good SNR estimator as it
is unbiased and has the smallest variance of SNR estimates.
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