Search results for "Decoding methods"
showing 10 items of 54 documents
A Multi-Phase Decode-and-Forward Transmission Protocol in Cognitive Relay Networks: Outage Analysis and Relay Power Allocation
2015
Consider an underlay cognitive relay network with multiple source and destination pairs and that a decode-and-forward scheme is adopted at the relay. We propose a multi-phase transmission protocol in this paper which involves cooperation among source, relay and destination nodes. Given perfect interference elimination before decoding at the destination nodes, we derive closed-form expressions for outage probability calculation over Rayleigh fading channels. Furthermore, the optimal relay power allocation factor which leads to minimal outage probability is determined. Numerical results reveal the conditions under which satisfactory performance can be achieved based on the proposed scheme.
Usage of moving nanoparticles for improved holographic recording
2013
Metal nanoparticles are used for different applications in holographic configurations. The metal nanoparticles are placed close to an object and encode it by a time varying random mask. A decoding mask is computed and used to obtain super-resolution digital hologram and eliminate the twin image and DC from a digital hologram. The method is also shown to be applicable for other optical methods.
Combined K-Best sphere decoder based on the channel matrix condition number
2008
It is known that sphere decoding (SD) methods can provide maximum-likelihood (ML) detection over Gaussian MIMO channels with lower complexity than the exhaustive search. Channel matrix condition number represents an important influence on the performance of usual detectors. Throughout this paper, two particular cases of a SD method called K-Best carry out a combined detection in order to reduce the computational complexity with predictable performance degradation. Algorithm selection is based on channel matrix condition number thresholding. K-Best is a suboptimal SD algorithm for finding the ML solution of a detection problem. It is based on a fixed complexity tree search, set by a paramete…
Speech-input multi-target machine translation
2007
In order to simultaneously translate speech into multiple languages an extension of stochastic finite-state transducers is proposed. In this approach the speech translation model consists of a single network where acoustic models (in the input) and the multilingual model (in the output) are embedded. The multi-target model has been evaluated in a practical situation, and the results have been compared with those obtained using several mono-target models. Experimental results show that the multi-target one requires less amount of memory. In addition, a single decoding is enough to get the speech translated into multiple languages.
Optical CDMA enhanced by nonlinear optics
2010
Intended for the next generation of optical access networks, OCDMA is of great interest to meet the demand of increasing the number of users per access fiber, especially as spectral phase coding increases its performance in the optical domain. This, however, requires handling broad spectra and short pulses, which are best dealt with using opto-electronic or all-optical devices instead of slower electronics. Among others, we demonstrate spectral-phase-coded OCDMA using a fiber-based saturable absorber as thresholding in the receiver.
Decoding Emotional Valence from Electroencephalographic Rhythmic Activity
2017
We attempt to decode emotional valence from electroencephalographic rhythmic activity in a naturalistic setting. We employ a data-driven method developed in a previous study, Spectral Linear Discriminant Analysis, to discover the relationships between the classification task and independent neuronal sources, optimally utilizing multiple frequency bands. A detailed investigation of the classifier provides insight into the neuronal sources related with emotional valence, and the individual differences of the subjects in processing emotions. Our findings show: (1) sources whose locations are similar across subjects are consistently involved in emotional responses, with the involvement of parie…
On axis holography by random particles encoding
2012
A method for eliminating the unwanted terms in an on axis hologram is presented. In this method, free randomly distributed nanoparticles are in proximity to the object and their Brownian motion encodes the spatial features of the object in the recorded hologram. The nanoparticles are localized and a decoding pattern is calculated for each frame. This decoding pattern is then used to remove the reference beam and the conjugate beam in the reconstruction of the hologram.
Rateless codes mitigation technique in a turbulent indoor Free Space Optics link
2014
Free Space Optics (FSO) links are affected by several impairments and, among them, optical turbulence is the most important factor that can degrade the link quality. Due to the presence of this phenomenon, the signal irradiance detected by the receiver fluctuates, thus causing erasure errors and fading events. In this work, we present an indoor Free Space Optics link, in which several turbulence conditions are generated by using two heating elements. We show that the generated turbulence causes erasure errors and packet losses during the data transmission, and we also compare the statistical distribution of the samples with the theoretical models. Moreover, we demonstrate how the applicatio…
Two-dimensional temporal coherence coding for super resolved imaging
2009
In this paper, we present an approach that can be used for transmission of 2D spatial information through space-limited systems capable of transmitting even only a single spatial pixel. The input 2D object is illuminated with temporally incoherent illumination. The axial coherence length is very short and it equals only a few microns. Attached to the input object spatial random phase mask generates different axial shift for every pixel of the input. The temporal delays of the encoding (axial shifts) of every pixel are longer than the coherence length of the illuminating source. Therefore no temporal correlation exists between the various pixels of the input. A lens combines all spatial pixe…
Superresolved imaging of remote moving targets.
2006
We present a superresolving approach that allows one to exceed the diffraction limit and recover highly resolved contours of moving targets from a sequence of low-resolution images. The presented approach is suitable for remote sensing applications. The resolution decoding algorithm that is used to recover the high-resolution features of the target can be run partially via optical means and that way can be used to reduce the required computational complexity.