A Unique Wavelet-based Multicarrier System with and without MIMO over Multipath Channels with AWGN

yesRecent studies suggest that multicarrier systems using wavelets outperform conventional OFDM systems using the FFT, in that they have well-contained side lobes, improved spectral efficiency and BER performance, and they do not require a cyclic prefix. Here we study the wavelet packet and discrete wavelet transforms, comparing the BER performance of wavelet transform-based multicarrier systems and Fourier based OFDM systems, for multipath Rayleigh channels with AWGN. In the proposed system zero-forcing channel estimation in the frequency domain has been used. Results confirm that discrete wavelet-based systems using Daubechies wavelets outperform both wavelet packet transform- based systems and FFT-OFDM systems in terms of BER. Finally, Alamouti coding and maximal ratio combining schemes were employed in MIMO environments, where results show that the effects of multipath fading were greatly reduced by the antenna diversity

“Multicarrier Modulation for Wireless Communication using Wavelet Packets

Success of OFDM has proved that Multi carrier modulation is an efficient solution for wireless communications. Wavelet Packet Modulation (WPM) is a new type of modulation for transmission of multicarrier signal on wireless channel that uses orthogonal wavelet bases other than sine functions. Though this modulation is over all similar to that of OFDM, it provides interesting additional features. In this thesis, a detailed study is given on Wavelets and WPM and the BER performance comparison between the OFDM systems and WPM systems and equalization techniques are analysed. The analysis is done for different types of wavelet generating families, various number of modulations QAM constellation points (16 to 64), and simulated over AWGN channel, and other Multipath fading channels

Performance Analysis of Massive MIMO-OFDM System Incorporated with Various Transforms for Image Communication in 5G Systems

Modern-day applications of fifth-generation (5G) and sixth-generation (6G) systems require fast, efficient, and robust transmission of multimedia information over wireless communication medium for both mobile and fixed users. The hybrid amalgamation of massive multiple input multiple output (mMIMO) and orthogonal frequency division multiplexing (OFDM) proves to be an impressive methodology for fulfilling the needs of 5G and 6G users. In this paper, the performance of the hybrid combination of massive MIMO and OFDM schemes augmented with fast Fourier transform (FFT), fractional Fourier transform (FrFT) or discrete wavelet transform (DWT) is evaluated to study their potential for reliable image communication. The analysis is carried over the Rayleigh fading channels and M-ary phase-shift keying (M-PSK) modulation schemes. The parameters used in our analysis to assess the outcome of proposed versions of OFDM-mMIMO include signal-to-noise ratio (SNR) vs. peak signal-to-noise ratio (PSNR) and SNR vs. structural similarity index measure (SSIM) at the receiver. Our results indicate that massive MIMO systems incorporating FrFT and DWT can lead to higher PSNR and SSIM values for a given SNR and number of users, when compared with in contrast to FFT-based massive MIMO-OFDM systems under the same conditions.publishersversionpublishe

Performance Of IEEE 802.11 OFDM With Multiple Frequency Transforms And Pulse Shaping Schemes

Orthogonal Frequency Division Multiplexing (OFDM) is employed in various communication systems such as the IEEE 802.11 wireless standards, in which both frequency transform, Fast Fourier Transform (FFT) and pulse shaping filter, Square Root Raised Cosine (SRRC) are used. The main contribution of this paper is the analysis of the performance of different combinations of frequency transforms and pulse shaping schemes for the 802.11n standard. The frequency transforms which have been used are: Fast Fourier Transforms (FFT), Discrete Wavelet Transforms (DWT) and Discrete Hartley Transform (DHT). The pulse shaping filters are the Raised Cosine (RC), SRRC and Flipped Exponential Pulse (FEXP). The IEEE 802.11 WLAN system with Additive White Gaussian (AWGN) has been used as the modelling environment. The results showed that the DWT-based OFDM system has a better performance than the DHT and FFT schemes and upon comparing the pulse shaping filters, the SRRC filter outperforms the FEXP and RC filters

Analysis of OFDM and WPOFDM Systems in Different Wireless Multipath Channels

In this paper, the performance analysis for orthogonal frequency division multiplexing (OFDM) and wavelet packet based OFDM (WPOFDM) systems over different wireless multipath channels has been investigated. The bit error rate (BER) performance for both systems is shown to be comparable and even at times better for OFDM especially in frequency selective fading channel at high values of S/N. Simulation results also show a significant enhancement for WPOFDM in terms of spectral efficiency and side-lobes suppression comparing to OFDM. Keywords: OFDM, WPOFDM, PSD, BER performance, wavelet filters, fading channels.

Performance Comparison of Wavelet Packet Transform (WPT) and FFT- OFDM System Based on QAM Modulation Parameters in Fading Channels

Abstract: -Orthogonal Frequency Division Multiplexing (OFDM) has been widely adopted in many applications due to its good spectral performance and low sensitivity to impulse noise and multipath channels. It has been widely adopted and standardized in many applications today. It is well known in OFDM that a cyclic prefix (CP) is appended to each symbol in order to mitigate the effect of Inter-Symbol-Interference (ISI). However, this reduces the spectral efficiency. A perfect reconstruction using wavelet packet transmultiplexer in OFDM transceiver counters the degrading effect of ISI, and also conserves bandwidth. In comparison to FFT-OFDM, Wavelet Packet Modulation (WPM) offers much lower side lobes in the transmitted signal, which reduces inter carrier interference (ICI) and narrowband interference (NBI). WPM improves spectral efficiency due to the exclusion of CP. Nevertheless, it requires an efficient equalization technique to counter the ISI and ICI. Wavelet based OFDM has been suggested to improve BER performance of transceiver in wireless communication. In this paper, a study of wavelet packet transform modulation WPT-OFDM scheme is conducted, and the performance comparison is made against the traditional FFT-OFDM over various fading channels. The analysis is done using various number of modulation QAM constellation points. Specifically, the analysis is on the effect of QAM constellation points in AWGN channel, flat fading channel and frequency selective fading channels. Simulation results using QAM Modulation points (8 to 64 Point), and the BER best performance of WPT-OFDM system is when the QAM Modulation parameter (QAM = 8) in all channels

Wavelet packet modulation a new equalization scheme

Multicarrier modulation systems have experienced a tremendous growth in complexity and possibilities during the past decade, allowing data transmission rates never before imagined, leading to the commercial appearing of high-definition video on demand on mobile scenarios, faster Ethernet connections, increased number of digital television channels, etc. This tremendous change came up with the application of OFDM in various branches related to information interchange: ADSL and VDSL networks, DVB, WLAN, digital radio, or even the 4th generation standard for mobile communications (LTE). Therefore, OFDM is a cornerstone for communication exchange, but at the same time there are some aspects that might be improved, especially its flexibility and spectral efficiency. Wavelet-Based communication systems have some advantages like lower transmitted signal Sidelobe Level (SLL), higher spectral efficiency as well as higher flexibility with respect to OFDM technology. However, there is an important lack for WPM systems: its structure is complex and there is a lack of specific equalization schemes for it. In this thesis, we will go in deep of the Wavelet Packet System and try to find an equivalent and more efficient model, that leads to a proper specific equalization to improve the characteristics of these systems. Then, after introducing Wavelet theory and the equalization methods, we will present the concept of a post-processing equalization scheme, whose main components will be described in detail. Afterwards the new system will be tested in different scenarios in order to verify and validate theoretical assumptions, to finally conclude this work with a summary of conclussions and related work.Ingeniería de Telecomunicació

Discrete Wavelet Transforms

The discrete wavelet transform (DWT) algorithms have a firm position in processing of signals in several areas of research and industry. As DWT provides both octave-scale frequency and spatial timing of the analyzed signal, it is constantly used to solve and treat more and more advanced problems. The present book: Discrete Wavelet Transforms: Algorithms and Applications reviews the recent progress in discrete wavelet transform algorithms and applications. The book covers a wide range of methods (e.g. lifting, shift invariance, multi-scale analysis) for constructing DWTs. The book chapters are organized into four major parts. Part I describes the progress in hardware implementations of the DWT algorithms. Applications include multitone modulation for ADSL and equalization techniques, a scalable architecture for FPGA-implementation, lifting based algorithm for VLSI implementation, comparison between DWT and FFT based OFDM and modified SPIHT codec. Part II addresses image processing algorithms such as multiresolution approach for edge detection, low bit rate image compression, low complexity implementation of CQF wavelets and compression of multi-component images. Part III focuses watermaking DWT algorithms. Finally, Part IV describes shift invariant DWTs, DC lossless property, DWT based analysis and estimation of colored noise and an application of the wavelet Galerkin method. The chapters of the present book consist of both tutorial and highly advanced material. Therefore, the book is intended to be a reference text for graduate students and researchers to obtain state-of-the-art knowledge on specific applications

MIMO Discrete Wavelet Transform for the Next Generation Wireless Systems

Study is presented into the performance of Fast Fourier Transform (FFT) and Discrete Wavelet Transform (DWT) and MIMO-DWT with transmit beamforming. Feedback loop has been used between the equalizer at the transmitter to the receiver which provided the channel state information which was then used to construct a steering matrix for the transmission sequence such that the received signals at the transmitter can be combined constructively in order to provide a reliable and improved system for next generation wireless systems. As convolution in time domain equals multiplication in frequency domain no such counterpart exist for the symbols in space, means linear convolution and Intersymbol Interference (ISI) generation so both zero forcing (ZF) and minimum mean squared error (MMSE) equalizations have been employed. The results show superior performance improvement and in addition allow keeping the processing, power and implementation cost at the transmitter which has less constraints and the results also show that both equalization algorithms perform alike in wavelets and the ISI is spread equally between different wavelet domains