Bit Error Rate (BER) Analysis of Conventional OFDM (DFT - OFDM) And Wavelet Based OFDM (DWT – OFDM)

OFDM has been widely adopted in many applications due to its good spectral performance and low sensitivity to impulse noise and multipath channels. In OFDM that a cyclic prefixes (CP) is appended to each symbol in order to mitigate the effect of Inter-Symbol-Interference (ISI) and intercarrier interference (ICI). However, this reduces the spectral efficiency. A perfect reconstruction using wavelet based OFDM provides good orthogonality and with its use Bit Error Rate is improved. Wavelet based system does not require CP, so spectrum efficiency is increased. In this paper, we are presenting BER analysis of conventional and wavelet based OFDM in LTE using different modulation techniques like QAM 2, QAM 4, QAM 16, QAM 256 and PSK. DOI: 10.17762/ijritcc2321-8169.15018

Improve the Performance of Orthogonal Frequency Division Multiplexing Based Discrete Wavelet Transform Using Cooperative Communication System

Cooperative communication mean remote hubs can help each other for communication. In this work, contemplate agreeable "Symmetrical Recurrence Division Multiplexing (OFDM)" based "Discrete wavelet change (DWT)".OFDM Cooperative l plan for multi-hub remote systems utilizing both Open up and-Forward (AF) and Decipher and-Forward (DF) handing-off. In this paper, an enhance the execution OFDM-DWT. We expect that the source and the transfer are gathered. Subsequent to interpreting, the transfer rearranges the information before transmitting towards the goal. Thus, the goal gets two individual imitations of the transmit flag and utilize decent variety consolidating. The bit mistake execution is offered, for the assembled organize. BER reenactment in channels An and B demonstrates that the handing-off convention bolstered agreeable OFDM-DWT framework beats flag. Recreation results express that the recommended remapping assorted variety strategy at the hand-off accomplishes a superior execution of OFDM-DWT based arranged hand-off correspondences Keywords—OFDM, DWT, AF, DF, cooperative DOI: 10.7176/NCS/10-03 Publication date:July 31st 201

Study: The Performance FFT and Wavelet Packet of OFDM Systems from through Demonstrated Numerical Examples

A major goal of the next-generation wireless communication systems is the development of a reliable highspeed wireless communication system that supports high user mobility. Multi-Carrier Modulation (MCM) technique is an attractive approach for high-speed digital radio communication systems in order to achieve a high spectral efficiency and to combat the frequency selectivity of the channel. Orthogonal frequency division multiplexing (OFDM) is a kind of MCM techniques. As proven by the success of OFDM, multicarrier modulation has been recognized as an efficient solution for wireless communications. Waveform bases other than sine functions could similarly be used for multicarrier systems in order to provide an alternative to OFDM. Wavelet Packet Modulation (WPM) was proposed as one of the multicarrier transmission methods like OFDM. Since it is a multicarrier transmission method. In this paper, we study the performance of FFT-OFDM and wavelet Packet (WP)- OFDM from through demonstrated numerical examples, and evaluation of FFT-OFDM and DWPT-OFDM in AWGN channel , Flat fading channel and Selective Fading Channel

The Manchester Coded Data Based OFDM (MCOFDM)

This paper shows a new DWT based OFDM algorithm which significantly simplifies signal processing in the transmitter and receiver. Unlike conventional DWT based OFDM a new algorithm does not use digital modulation of subcarriers either IDWT in the transmitter. The output signal from the transmitter is formed by summing the signals on the individual subchannels, encoded with the Manchester code and sampled at appropriate frequencies. In the receiver, the channel signal and data is reconstructed using DWT and Haar wavelet. Although the signal transmission is achieved using amplitude modulation, the paper shows that BER performance is commensurable to BPSK or DMWT based OFDM in the presence of AWGN

PCA Assisted DTCWT Denoising for Improved DOA Estimation of Closely Spaced and Coherent Signals

Performance of standard Direction of Arrival (DOA) estimation techniques degraded under real-time signal conditions. The classical algorithms are Multiple Signal Classification (MUSIC), and Estimation of Signal Parameters via Rotational Invariance Technique (ESPRIT). There are many signal conditions hamper on its performance, such as closely spaced and coherent signals caused due to the multipath propagations of signals results in a decrease of the signal to noise ratio (SNR) of the received signal. In this paper, a novel DOA estimation technique named CW-PCA MUSIC is proposed using Principal Component Analysis (PCA) to threshold the nearby correlated wavelet coefficients of Dual-Tree Complex Wavelet transform (DTCWT) for denoising the signals before applying to MUSIC algorithm. The proposed technique improves the detection performance under closely spaced, and coherent signals with relatively low SNR conditions. Also, this method requires fewer snapshots, and less antenna array elements compared with standard MUSIC and wavelet-based DOA estimation algorithms

Performance Improvement of Neural Network Based RLS Channel Estimators in MIMO-OFDM Systems

The objective of this study was tointroduce a recursive least squares (RLS) parameter estimatorenhanced by using a neural network (NN) to facilitate the computing of a bit error rate (BER) (error reduction) during channels estimation of a multiple input-multiple output orthogonal frequency division multiplexing (MIMO-OFDM) system over a Rayleigh multipath fading channel.Recursive least square is an efficient approach to neural network training:first, the neural network estimator learns to adapt to the channel variations then it estimates the channel frequency response. Simulation results show that the proposed method has better performance compared to the conventional methods least square (LS) and the original RLS and it is more robust at high speed mobility

Diversity technique using discrete wavelet transform in OFDM system

Spectrum usage due to an increasing number of mobile users using services like audio, video, and images is one of the challengings for wireless communication. Orthogonal Frequency Division Multiplexing (OFDM) is one of the promising techniques to increase spectral efficiency. However, the conventional OFDM using fast fourier transform (FFT) still has the drawback of reducing spectral efficiency. Discrete wavelet transforms (DWT) has been used as an alternative method replacing FFT to increase the spectral efficiency. This paper presents the fundamental of wavelets and their significance in wireless communication. A review of the literature has been done on how the DWT-OFDM performs better when compared to FFT-OFDM and on diversity technique such as transmit and receive diversity. The advantages of using diversity at both receiver and transmitter, i.e., Multiple inputs and multiple output systems and the overview of the technique is also considered. The flexibility, improve in the performance of BER, mitigate the interference DWT-OFDM with diversity at both transmitter and receiver provides emerging technology for future generation