Errors per scale statistics for a wavelet OFDM transmission in flat fading channels

Oltean, Marius; Nafornita, Miranda

doi:10.1109/wisp.2009.5286532

Cited by 16 publications

(6 citation statements)

References 10 publications

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“…From figure 1 we can observe that the proposed OFDM system only increases Haar wavelet transformation at the transmitter compared with the conventional OFDM system. Some literatures use wavelet transformation to substitute the Fourier transform unit [7][8][9], which is different from our paper. In this paper we use both wavelet transformation and Fourier transform unit.…”

Section: Iiiproposed Ofdm Systemmentioning

confidence: 84%

“…The Wavelet-OFDM system was widely studied in [7][8][9]. Wavelet-OFDM system just substitutes the DFT and IDFT with DWT and IDWT, respectively.…”

Section: Iintroductionmentioning

confidence: 99%

“…In high speed digital wireless applications, the intersymbol interference (ISI) channel may have spectral nulls, which may degrade the performance of the existing OFDM system. Hence PAPR and spectral null channels need to be handled properly in implementation of OFDM systemsThe Wavelet-OFDM system was widely studied in [7][8][9]. Wavelet-OFDM system just substitutes the DFT and IDFT with DWT and IDWT, respectively.…”

mentioning

confidence: 99%

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A Performance Analaysis of BPSK OFDM System by Novel Based Haar Wavelet

T.V.Ramesh¹,

prakash²

2014

IJAREEIE

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orthogonal frequency division multiplexing (OFDM) is the most popular modulation technique in modern wireless communication systems. Even though there are many advantages of OFDM, it has two main drawbacks: High peak-to-average power ratio (PAPR) and frequency offset. In this paper the issue of PAPR in OFDM is discussed. Due to the large number of subcarriers used, OFDM systems have a large dynamic signal range with a very high peak-to-average-power ratio (PAPR) which makes OFDM sensitive to nonlinear effects. This paper proposes a novel Haar-Wavelet based BPSK OFDM system. The Haar Wavelet transformation decomposes the data symbol sequence like half of the data symbols are zeros and the rest are √2 or -√2 and we can have the PAPR reduced by 3dB at most, compared with the conventional OFDM system. In this paper we propose a novel decoding algorithm for the proposed OFDM system, derive the bit error rate performance in theory. We compare cumulative distribution function for PAPR for the proposed OFDM v/s conventional OFDM and finally we compare the BER performance of our proposed OFDM system with the conventional one.KEYWORDS: Peak-to-average power ratio(PAPR); Bit error rate(BER); Haar Wavelet; Orthogonal frequency division multiplexing(OFDM); I.INTRODUCTIONAfter more than thirty years of research and developments carried out in different places, orthogonal frequency division multiplexing (OFDM) has been widely implemented in high speed digital communications. Due to the recent advancements in digital signal processing (DSP) and very large scale integrated circuits (VLSI) technologies, the initial obstacles of OFDM implementations do not exist anymore. Mean-while, the use of Fast Fourier transform (FFT) algorithms has eliminated arrays of sinusoidal generators and coherent demodulation required in parallel data systems and made the implementation of the technology cost effective. In recent years OFDM has gained a lot of interest in diverse communication applications. This has been due to its favorable properties like high spectral efficiency and robustness to channel fading. Recently OFDM has become the technique of choice for many broadband applications, such as asymmetric digital subscriber line (ADSL) modems, digital audio broadcasting (DAB)[1], digital video broadcasting(DVB)[2] and wireless local area networks (WLAN) systems (IEEE 802.11a [3], IEEE 802.11g [4]. In the conventional serial data transmission system, the information symbols are transmitted sequentially where each symbol occupies the entire available spectrum bandwidth. But in the OFDM system, the information is converted to N parallel sub channels and sent at lower rates using frequency division multiplexing. The subcarrier frequency spacing is selected carefully such that each subcarrier is located on the other sub-carrier zero crossing points. This implies that there is overlapping among the subcarriers but will not interfere with each other, if they are sampled at the subcarrier frequencies. This means that all subcarriers are orth...

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Section: Iiiproposed Ofdm Systemmentioning

confidence: 84%

“…The Wavelet-OFDM system was widely studied in [7][8][9]. Wavelet-OFDM system just substitutes the DFT and IDFT with DWT and IDWT, respectively.…”

Section: Iintroductionmentioning

confidence: 99%

mentioning

confidence: 99%

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A Performance Analaysis of BPSK OFDM System by Novel Based Haar Wavelet

T.V.Ramesh¹,

prakash²

2014

IJAREEIE

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“…In the wavelet-OFDM system proposed in this paper, IFFT and FFT operations are used to combine different subcarriers into a composite time-domain signal. But papers [33][34][35] use inverse discrete wavelet transform (IDWT) and DWT instead of IFFT and FFT, which aim to suppress the ICI and ISI. Paper [35] also investigated different wavelets to adapt to the specific channel environment.…”

Section: Proposed Haar Wavelet Decision Feedback Channel Estimation Mmentioning

confidence: 99%

“…Paper [35] also investigated different wavelets to adapt to the specific channel environment. The Haar wavelet is used as subcarriers in [33][34][35]. In this paper, Haar wavelet decomposition is used for suppressing noise existing at the estimated channel coefficients in time-domain.…”

Section: Proposed Haar Wavelet Decision Feedback Channel Estimation Mmentioning

confidence: 99%

A Haar Wavelet Decision Feedback Channel Estimation Method in OFDM Systems

2018

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Channel estimation is a key technology in improving the performance of the orthogonal frequency division multiplexing (OFDM) system. The pilot-based channel estimation method decreases the spectral efficiency and data transmission rate. Some conventional channel estimation methods cannot suppress the noise effectively, which affects the quality of the final received signals. To solve these two problems, a Haar wavelet decision feedback (DF) channel estimation method, also named the Haar wavelet method, is proposed in this paper. The proposed Haar wavelet method can suppress the noise existing at the estimated channel impulse response (CIR) effectively, based on a time-domain threshold which is a standard deviation of noise obtained by wavelet decomposition. At the same time, the proposed Haar wavelet method just requires inserting one block pilot symbol in front of the first OFDM symbol, which therefore improves the data transmission rate and spectrum efficiency greatly. Simulation results are shown to verify the effectiveness of the proposed Haar wavelet method in multipath channel propagation conditions.

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