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Wyszukujesz frazę "denoising threshold" wg kryterium: Temat


Wyświetlanie 1-3 z 3
Tytuł:
Performance of a Software Defined Radio based Non-Coherent OFDM Wireless Link
Autorzy:
Narayana, Nandana
Sure, Pallaviram
Powiązania:
https://bibliotekanauki.pl/articles/27311898.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
Software Defined Radio (SDR)
Universal Software Radio Peripheral (USRP)
LabView
LS channel estimation
denoising threshold
Opis:
With improved technological successions, wireless communication applications have been incessantly evolving. Owing to the challenges posed by the multipath wireless channel, radio design prototypes have become elemental in all wireless systems before deployment. Further, different signal processing requirements of the applications, demand a highly versatile and reconfigurable radio such as Software Defined Radio (SDR) as a crucial device in the design phase. In this paper, two such SDR modules are used to develop an Orthogonal Frequency Division Multiplexing (OFDM) wireless link, the technology triumphant ever since 4G. In particular, a non-coherent end-to-end OFDM wireless link is developed in the Ultra High Frequency (UHF) band at a carrier frequency of 470 MHz. The transmitter includes Barker sequences as frame headers and pilot symbols for channel estimation. At the receiver, pulse alignment using Max energy method, frame synchronization using sliding correlator approach and carrier offset correction using Moose algorithm are incorporated. In addition, wireless channel is estimated using Least Square (LS) based pilot aided channel estimation approach with denoising threshold and link performance is analyzed using average Bit Error Rate (BER), in different pilot symbol scenarios. In a typical laboratory environment, the results of BER versus receiver gain show that with 4 pilot symbols out of 128 carriers, at a gain of 20 dB, BER is 0.160922, which is reduced to 0.136884 with 16 pilot symbols. The developed link helps OFDM researchers to mitigate different challenges posed by the wireless environment and thereby strengthen OFDM technology.
Źródło:
International Journal of Electronics and Telecommunications; 2023, 69, 3; 537--544
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On the Comparison of Various Overhead Arrangements for Massive MIMO-OFDM Channel Estimation
Autorzy:
Sure, P.
Bhuma, C. M.
Powiązania:
https://bibliotekanauki.pl/articles/226978.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Massive MIMO-OFDM
time domain synchronous
comb type with cyclic prefix
grid type with cyclic prefix
denoising threshold
LS channel estimation
Opis:
Massive multi input multi output (MIMO) systems incorporate orthogonal frequency division multiplexing (OFDM) technology to render high data rate services for future wireless communication applications. The channel estimator (CE) employed by a reliable massive MIMO-OFDM system requires huge amount of overhead in the form of known and null data transmissions, hence limiting the system spectral efficiency (SE). Often, CE design is a tradeoff between SE and system reliability. In this paper, CE with three different overhead arrangements, namely time domain synchronous (TDS), comb type with cyclic prefix (CTCP), 2D grid type with cyclic prefix (GTCP) are investigated and a GTCP based CE is proposed which offers both high SE and improved system reliability. The proposed CE uses autocorrelation based denoising threshold for channel impulse response (CIR) estimation and does not require any knowledge of channel statistics (KCS). A416 MIMO-OFDM system is simulated in a rayleigh fading channel environment with U-shaped doppler spectrum. From the bit error rate (BER) performance results in WiMax SUI-4, Advanced Television Technology Center (ATTC) and Brazil A channel environments, it is verified that the proposed CE with GTCP overhead and proposed denoising scheme, indeed improves both SE and system reliability. Hence it is suitable for application in all massive MIMO-OFDM systems.
Źródło:
International Journal of Electronics and Telecommunications; 2014, 60, 2; 173-179
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Acoustic Identification of Dolphin Whistle Types in Deep Waters of Arabian Sea Using Wavelet Threshold Denoising Approach
Autorzy:
Mahanty, Madan Mohan
Cheenankandy, Sanjana M.
Latha, Ganesan
Raghuraman, Govindan
Venkatesan, Ramasamy
Powiązania:
https://bibliotekanauki.pl/articles/31339921.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
deep water ambient noise
Arabian Sea
wavelet threshold denoising
impulsive shackle noise
dolphin whistle types
Opis:
In situ time series measurements of ocean ambient noise, have been made in deep waters of the Arabian Sea, using an autonomous passive acoustic monitoring system deployed as part of the Ocean Moored buoy network in the Northern Indian Ocean (OMNI) buoy mooring operated by the National Institute of Ocean Technology (NIOT), in Chennai during November 2018 to November 2019. The analysis of ambient noise records during the spring (April–June) showed the presence of dolphin whistles but contaminated by unwanted impulsive shackle noise. The frequency contours of the dolphin whistles occur in narrow band in the range 4–16 kHz. However, the unwanted impulsive shackle noise occurs in broad band with the noise level higher by ~20 dB over the dolphin signals, and it reduces the quality of dolphin whistles. A wavelet based threshold denoising technique followed by a subtraction method is implemented. Reduction of unwanted shackle noise is effectively done and different dolphin whistle types are identified. This wavelet denoising approach is demonstrated for extraction of dolphin whistles in the presence of challenging impulsive shackle noise. Furthermore, this study should be useful for identifying other cetacean species when the signal of interest is interrupted by unwanted mechanical noise.
Źródło:
Archives of Acoustics; 2023, 48, 1; 39-48
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-3 z 3

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