Results 21 to 30 of about 416,241 (288)
Optimum Watermark Detection and Embedding in Digital Images [PDF]
, 1998 This work concentrates on the problem of watermarking of still images using the luminance component, through the use of spread spectrum techniques, both in space (direct sequence spread spectrum or DSSS) and frequency (frequency hopping or FH), following
Sayrol Clols, Elisa +1 more
core +1 more source
Code Synchronization Algorithm Based on Segment Correlation in Spread Spectrum Communication
Algorithms, 2015 Spread Spectrum (SPSP) Communication is the theoretical basis of Direct Sequence Spread Spectrum (DSSS) transceiver technology. Spreading code, modulation, demodulation, carrier synchronization and code synchronization in SPSP communications are the core
Aohan Li +4 more
doaj +1 more source
IET Signal Processing, 2022 The Shannon‐Nyquist sampling theorem that is based on narrowband interference (NBI) detection and parameter estimation methods in direct sequence spread spectrum (DSSS) communication is limited by the high sampling rate.
Zengkai Shi +4 more
doaj +1 more source
Tongxin xuebao, 2022 To solve the performance limitation of direct sequence spread spectrum system in complex multipath environment, an adaptive anti-jamming spread spectrum framework that organically combines single carrier frequency domain equalization (SCFDE) and direct ...
Fanglin GU +4 more
doaj +2 more sources
On the use of a suppression filter for CDMA overlay [PDF]
, 1999 This paper is concerned with a direct-sequence code-division multiple-access (DS-CDMA) system operating over a Rayleigh fading channel and sharing a common spectrum with a narrow-band waveform.
Wang, J
core +1 more source
A novel approach to security enhancement of chaotic DSSS systems [PDF]
, 2016 In this paper, we propose a novel approach to the enhancement of physical layer security for chaotic direct-sequence spread-spectrum (DSSS) communication systems. The main idea behind our proposal is to vary the symbol period according to the behavior of
Barlet Ros, Pere +3 more
core +1 more source
Spectrally Shaped Generalized Multitone Direct Sequence Spread Spectrum
IEEE Transactions on Vehicular Technology, 2005 We propose a new modulation scheme called spectrally shaped generalized multitone direct-sequence spread spectrum (S-MT-DS-SS), with adjustable parameters on each subcarrier. The parameters we adjust are each subcarrier signal's amplitude, data rate, chip rate, and the frequency separation between subcarriers.
Matolak, David W, Xiong, Wenhui
openaire +3 more sources
A Chaos-Based Secure Direct-Sequence/Spread-Spectrum Communication System
Abstract and Applied Analysis, 2013 This paper proposes a chaos-based secure direct-sequence/spread-spectrum (DS/SS) communication system which is based on a novel combination of the conventional DS/SS and chaos techniques.
Nguyen Xuan Quyen +2 more
doaj +1 more source
New bounds on RAKE structures for DS-CDMA over frequency-selective Rayleigh fading channels [PDF]
, 1996 An upper bound is derived for the probability of error in an asynchronous binary direct-sequence spread-spectrum multiple-access communications system operating over frequency selective Rayleigh fading channels. A coherent RAKE receiver with predetection
Calvo Zorrilla, Sergio +1 more
core +1 more source
Non-noticeable information embedding in color images: marking and detection [PDF]
, 1999 One of the problems arising from the use of digital media is the ease of obtaining identical copies of digital images or audio files, allowing manipulation and unauthorized use. Copyright is an effective tool for preserving intellectual property of those
Cabanillas, Silvia +3 more
core +1 more source