Chaos MIMO transmission with variable chaos signal processing for performance improvement

2014 ◽  
Vol 1 ◽  
pp. 666-669
Author(s):  
Eiji Okamoto
Keyword(s):  
Signal Processing ◽  
Performance Improvement ◽  
Mimo Transmission

scholarly journals PERFORMANCE IMPROVEMENT IN SPREAD SPECTRUM IMAGE WATERMARKING USING WAVELETS

2011 ◽  
Vol 09 (01) ◽  
pp. 1-33 ◽  
Author(s):  
SANTI P. MAITY ◽  
MALAY K. KUNDU
Keyword(s):  
Signal Processing ◽  
Wavelet Transform ◽  
Performance Improvement ◽  
Digital Image ◽  
Spread Spectrum ◽  
Image Watermarking ◽  
Discrete Wavelet ◽  
Digital Image Watermarking ◽  
Hidden Information ◽  
Hidden Data

This paper investigates the scope of wavelets for performance improvement in spread spectrum image watermarking. Performance of a digital image watermarking algorithm, in general, is determined by the visual invisibility of the hidden data (imperceptibility), reliability in the detection of the hidden information after various common and deliberate signal processing operations (robustness) applied on the watermarked signals and the amount of data to be hidden (payload) without affecting the imperceptibility and robustness properties. In this paper, we propose a few spread spectrum (SS) image watermarking schemes using discrete wavelet transform (DWT), biorthogonal DWT and M-band wavelets coupled with various modulation, multiplexing and signaling techniques. The performance of the watermarking methods are also reported along with the relative merits and demerits.

scholarly journals Faster-than-Nyquist Signal Processing Based on Unequal Error Probability for High-Throughput Wireless Communications

2019 ◽  
Vol 9 (12) ◽  
pp. 2413
Author(s):  
Chang-Uk Baek ◽  
Ji-Won Jung
Keyword(s):  
Signal Processing ◽  
Performance Improvement ◽  
Orthogonal Frequency Division Multiplexing ◽  
Error Probability ◽  
Probability Method ◽  
Frequency Division ◽  
Improve Performance ◽  
Group A ◽  
Nyquist Rate ◽  
Better Than

Faster-than-Nyquist (FTN) signal processing, which transmits signals faster than the Nyquist rate, is a representative method for improving throughput efficiency sacrificed performance degradation due to inter-symbol interference. To overcome this problem, this paper proposed FTN signal processing based on the unequal error probability to improve performance. The unequal error probability method divides encoded bits into groups according to priority, and FTN interference rates are differently applied to each group. A lower FTN interference ratio is allocated to the group to which high-priority encoded bits belong and a higher FTN interference ratio is allocated to the group to which low-priority encoded bits belong, thus performance improvement can be obtained compared to the conventional FTN method, with the same interference ratio. In addition, we applied the proposed FTN signal processing, based on the unequal error probability method, to the OFDM (orthogonal frequency division multiplexing) system in multipath channel environments. In the simulations, the performance of the proposed method was better than that of the conventional FTN method by about 0.2 dB to 0.3 dB, with an interference ratio of 20%, 30%, and 40%. In addition, in multipath channels, we confirmed that by applying the proposed unequal error probability, the OFDM-FTN method improves performance to a larger extent than the conventional OFDM-FTN method.

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