scholarly journals Wavelet Transform Application Based on Matlab Simulation

2020 ◽  
Vol 36 (1) ◽  
Author(s):  
Tan Nguyen Minh ◽  
Hua-Ming Chen ◽  
Binh Duong Giap ◽  
Hoang Le Quang Nhat
Keyword(s):  
Wavelet Transform ◽  
Orthogonal Frequency Division Multiplexing ◽  
Multiple Input Multiple Output ◽  
Simulation Software ◽  
Discrete Wavelet ◽  
Matlab Simulation ◽  
Ofdm System ◽  
High Data ◽  
Input Multiple Output ◽  
Mimo Ofdm

Multiple Input Multiple Output (MIMO) and Orthogonal Frequency Division Multiplexing (OFDM) are two combined technologies to provide the spectral efficiency and high data rate required for 4G, 5G wireless systems. Discrete Wavelet Transform (DWT) is presented as an alternative for Fast Fourier Transform (FFT) since there is no necessity for Cyclic Prefix (CP) due to the overlapping properties of DWT. By a simple replacement of the FFT with DWT in MIMO OFDM system, an improvement of performances has been detected which leads to a new system scenario DWT-based MIMO-OFDM. In this thesis, such a system is simulated and the performance of Bit Error Rate (BER) is analyzed to determine the different types of wavelets in various channel condition with different modulations (4, 16, 64 -QAM). Therefore, DWT-based MIMO-OFDM in comparison with DFT-based MIMO-OFDM system was investigated using MATLAB simulation software. And besides, I would like to refer to use Neural Network algorithms to replace Wavelet transform in the next research.

A New Method for MIMO-OFDM Channel Estimation Based on Discrete Wavelet Transform

2012 ◽  
Vol 182-183 ◽  
pp. 2066-2070
Author(s):  
Hui Shi ◽  
Ren Wang Song ◽  
Gang Fei Wang
Keyword(s):  
Wavelet Transform ◽  
Channel Estimation ◽  
Discrete Wavelet Transform ◽  
Orthogonal Frequency Division Multiplexing ◽  
Multiple Input Multiple Output ◽  
Mimo Channel ◽  
Discrete Wavelet ◽  
Input Multiple Output ◽  
Estimation Scheme ◽  
Mimo Ofdm

This paper puts forward a suitable channel estimation scheme for multiple input multiple output and orthogonal frequency division multiplexing system (MIMO-OFDM) based on discrete wavelet transform. According to the least-squares standard (LS), this plan uses pilot to estimate the unit impulse response of MIMO channel firstly, then does wavelet denoising in changing domain, in order to reduce the frequency spectrum leakage and improve the estimation precision. At the same time, this method does not need to know channel information in advance, and can follow up the changes of channel on time with good error rate performance.

Spectral Efficiency in Wireless Networks through MIMO-OFDM System

2017 ◽  
pp. 249-277
Author(s):  
Shuvabrata Bandopadhaya ◽  
Jibendu Sekhar Roy
Keyword(s):  
Orthogonal Frequency Division Multiplexing ◽  
Multiple Input Multiple Output ◽  
Wireless Channel ◽  
Estimation Methods ◽  
Ofdm System ◽  
Spectrum Utilization ◽  
High Data ◽  
Rate Transmission ◽  
Input Multiple Output ◽  
Mimo Ofdm

The traffic in Wireless Sensor Network (WSN) is brusty in nature; when any incident takes place, the data load on the channel increases suddenly demanding large channel spectrum. The scarcity of spectrum is the major technical obstacle for high data rate transmission along with better quality of service in any kind of wireless network. Hence it is very essential to enhance the spectrum efficiency of wireless channel. The major technical advancement in the physical layer which brings feasibility of broadband data transmission without increasing the transmission bandwidth or transmitting power are implementation of Multiple Input Multiple Output (MIMO) communication system with Orthogonal Frequency Division Multiplexing (OFDM) as modulation schemes. This chapter includes the fundamental concept of MIMO-OFDM system along with the channel estimation methods and the spectrum utilization issues therein.

scholarly journals Covert Communication in MIMO-OFDM System Using Pseudo Random Location of Fake Subcarriers

2016 ◽  
Vol 4 (1) ◽  
pp. 150-163 ◽  
Author(s):  
Rizky Pratama Hudhajanto ◽  
I Gede Puja Astawa ◽  
Amang Sudarsono
Keyword(s):  
Communication Systems ◽  
Orthogonal Frequency Division Multiplexing ◽  
Random Sequence ◽  
Multiple Input Multiple Output ◽  
Ofdm System ◽  
Transmission Scheme ◽  
Sensitive Data ◽  
Input Multiple Output ◽  
Mimo Ofdm ◽  
Random Location

Multiple-Input Multiple-Output Orthogonal Frequency Division Multiplexing (MIMO-OFDM) is the most used wireless transmission scheme in the world. However, its security is the interesting problem to discuss if we want to use this scheme to transmit a sensitive data, such as in the military and commercial communication systems. In this paper, we propose a new method to increase the security of MIMO-OFDM system using the change of location of fake subcarrier. The fake subcarriers’ location is generated per packet of data using Pseudo Random sequence generator. The simulation results show that the proposed scheme does not decrease the performance of conventional MIMO-OFDM. The attacker or eavesdropper gets worse Bit Error Rate (BER) than the legal receiver compared to the conventional MIMO-OFDM system.

scholarly journals Channel capacity and performance evaluation of precoded MIMO-OFDM system with large-size constellation

2019 ◽  
Vol 9 (6) ◽  
pp. 5024
Author(s):  
Hussein A. Leftah ◽  
Huda N. Alminshid
Keyword(s):  
Fading Channels ◽  
Channel Capacity ◽  
Orthogonal Frequency Division Multiplexing ◽  
Multiple Input Multiple Output ◽  
Ofdm System ◽  
Large Size ◽  
Multiple Input ◽  
Input Multiple Output ◽  
Mimo Ofdm ◽  
And Performance

<p>Multiple input-multiple output (MIMO) is a multipath diversity exploring approach which is emerged with orthogonal frequency division multiplexing (OFDM) to produce MIMO-OFDM that is widely used in wireless communications. This paper presents a discrete Hart-ley transform (DHT) precoded MIMO-OFDM system over multipath frequency-selective fading channel with large-size quadrature amplitude modulation (16-QAM, 64-QAM and 256-QAM). A mathematical models for the BER and channel capacity over mutlipath fading channels are also derived in this paper. Average Bit-error-rate (BER) and channel capacity of the presented system is considered and compared with that of the traditional MIMO-OFDM. Simulation results shows that the transmission performance and channel capacity of the proposed schemes is better than that of the traditional MIMO-OFDM without a pre-coder.</p>

scholarly journals Improving MIMO-OFDM Performance with Convolutional Coding and Discrete Wavelet Transform

2020 ◽  
pp. 299-305
Author(s):  
Saad S. Hreshee ◽  
◽  
Qais K. Al-Gayem
Keyword(s):  
Wavelet Transform ◽  
Discrete Wavelet Transform ◽  
Fading Channel ◽  
Orthogonal Frequency Division Multiplexing ◽  
Rayleigh Fading ◽  
Rician Fading ◽  
Discrete Wavelet ◽  
Ofdm System ◽  
Convolutional Coding ◽  
Mimo Ofdm

This paper presents a new way to improve the performance of MIMO-OFDM (multiple input multiple output - orthogonal frequency division multiplexing) by reducing the Bit Error Rate (BER) using both Convolutional Coding (CC) and discrete wavelet transform (DWT). In this Paper, OFDM system was simulated and studied with three models, SISO-OFDM, MISO-OFDM and MIMO-OFDM. The final system (MIMO-OFDM) has been improved by using CC at a coding rate 1/2 and using a DWT instead of FFT and then using both CC and DWT. The communication channels used in the study are Rician and Rayleigh fading channels and the modulation technique is Binary Phase-Shift Keying (BPSK) with 64 number of carrier frequencies. The results showed that the use of both convolutional coding and discrete wavelet transform in the MIMO-OFDM system reduces the bit energy to the intensity of noise energy (Eb/N0) by 3.4 dB as the Rayleigh fading channel is used and 4.6 dB as the Rician fading channel is used when BER=10-3. The results were obtained by modeling in the MATLAB program.

scholarly journals Uplink Multiuser MIMO-OFDM System in the Presence of Phase Noises, Power Imbalance, and Correlation

2018 ◽  
Vol 2018 ◽  
pp. 1-8
Author(s):  
Xiaoming Chen ◽  
Andreas Wolfgang ◽  
Tommy Svensson
Keyword(s):  
Orthogonal Frequency Division Multiplexing ◽  
Mimo Systems ◽  
Multiple Input Multiple Output ◽  
Base Station ◽  
Closed Form Expression ◽  
Ofdm System ◽  
Multiuser Mimo ◽  
Single Antenna ◽  
Input Multiple Output ◽  
Mimo Ofdm

The effects of phase noises (PNs), power imbalances, and correlations on multiuser orthogonal frequency division multiplexing (OFDM) multiple-input multiple-output (MIMO) systems are studied. It is assumed that each user is equipped with a single antenna, whereas the base station (BS) has multiple antennas and use zero-forcing (ZF) decoder for multiuser detection. Since each user has an independent oscillator, the received uplink (UL) signal at each BS antenna is corrupted by all of these independent PNs. Furthermore, there may be power imbalances and correlations (due to common scatterers) between different users. These impairments are jointly analyzed in this work. A closed-form expression of the mean square error (MSE) performance of the multiuser MIMO-OFDM system is derived. The analytical results are verified by simulations.

scholarly journals Experimental Evaluation of MIMO-OFDM System with Rateless Space-Time Block Code

2019 ◽  
Vol 2019 ◽  
pp. 1-8 ◽  
Author(s):  
Ali H. Alqahtani ◽  
Khaled Humadi ◽  
Ahmed Iyanda Sulyman ◽  
Abdulhameed Alsanie
Keyword(s):  
Orthogonal Frequency Division Multiplexing ◽  
Multiple Input Multiple Output ◽  
Block Code ◽  
Space Time ◽  
Ofdm System ◽  
Time Block ◽  
Space Time Block Code ◽  
Field Programmable ◽  
Input Multiple Output ◽  
Mimo Ofdm

Multiple-input multiple-output (MIMO) wireless technology in combination with orthogonal frequency-division multiplexing (MIMO-OFDM) is an attractive technique for next-generation wireless systems. However, the performance of wireless links is severely degraded due to various channel impairments which cause a decoding failure and lead to packet loss at the receiver. One technique to cope with this problem is the rateless space-time block code (RSTBC). This paper presents experimental results on the performance of a 2×2 MIMO-OFDM system with RSTBC as measured in a testbed implemented with field-programmable gate array (FPGA). The average bit error rate (BER) performance of the proposed scheme is evaluated experimentally, and the results agree closely with simulation and analytical upper bound. It has been shown that RSTBC can be implemented in real-world scenarios and guarantee the reliability of loss-prone wireless channels.

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