Wavelet packet based OFDM radar signals

Mohseni, Reza Moosavi; Sheikhi, A.; Shirazi, Mohammad Ali Masnadi

doi:10.1109/radar.2008.4653985

Cited by 10 publications

(12 citation statements)

References 11 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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“…Multicarrier signals using orthogonal frequency division multiplexing (OFDM) have recently been prompting much interest among researchers, because of their prominent properties such as a favourable ambiguity function, high bandwidth efficiency, and others [1][2][3][4][5][6][7][8]. Multicarrier OFDM signals bring many advantages to radar such as low probability of intercept, frequency diversity, improved target detection performance, and optimisation of both radar transmitter and receiver [9][10].…”

Section: Introductionmentioning

confidence: 99%

Digital constant‐envelope modulation scheme for radar using multicarrier OFDM signals

Qian

Jiang

2017

IET signal process.

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Multicarrier signals using orthogonal frequency division multiplexing (OFDM) bring many advantages to radar such as low probability of intercept, improved target detection performance, optimisation of both radar transmitter and receiver etc. A major drawback of multicarrier OFDM signals is their high peak-to-mean envelope power ratio, which reduces the working efficiency of the used power amplifiers. To solve this problem, a digital constant-envelope modulation scheme is proposed for radar using multicarrier OFDM signals. The scheme can transmit multicarrier OFDM signals through power amplifiers being operated near saturation levels (and thus maximising power efficiency) with little spectral distortion, even in the presence of channel mismatch. Given the speed limitations of field programmable gate arrays (FPGAs), the proposed scheme is implemented in an FPGA at intermediate frequency level using a polyphase processing structure.

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“…The main advantage of using WPM is that it is a very flexible system. Furthermore, it has been shown that using WPM is more robust to narrowband interference and multipath propagation loss than OFDM, Also Wavelet OFDM signals are more spectrally efficient than the conventional OFDM signals [6]. WPM and OFDM, members of the MCM waveform family, have an inherent capability to deal with multipath induced, frequency selective fading.…”

Section: Introductionmentioning

confidence: 99%

Performance analysis of QAM-modulation parameters on wavelet packet transform (WPT) and FFT-OFDM system

Taha

Salleh

2009

2009 IEEE 9th Malaysia International Conference on Communications (MICC)

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In Orthogonal Frequency Division Multiplexing (OFDM) a cyclic prefix (CP) is appended to each symbol in order to mitigate the effect of Inter-Symbol-Interference (ISI). However this leads to spectral inefficiency. A perfect reconstruction using wavelet packet transmultiplexer in OFDM transceiver counters the degrading effect of ISI, and also conserves bandwidth. In this paper the BER performance comparison between the OFDM systems that utilise the conventional Discrete Fourier Transform (DFT) and Discrete Wavelet Packet Transform (DWPT) respectively is analyzed. The analysis is done for various number of modulation QAM constellation points (8 to 64), and simulated over AWGN channel. Simulation results show that the best BER performance exhibits by the WPT-OFDM system, when the number of modulation QAM is 8.

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Wavelet packet based OFDM radar signals

Cited by 10 publications

References 11 publications

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

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

Digital constant‐envelope modulation scheme for radar using multicarrier OFDM signals

Performance analysis of QAM-modulation parameters on wavelet packet transform (WPT) and FFT-OFDM system

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