Specific neural coding (SNC) forms the basis of information processing in bio-brain, which generates distinct patterns of neural coding in response to corresponding exterior forms of stimulus. The performance of SNC i...
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Specific neural coding (SNC) forms the basis of information processing in bio-brain, which generates distinct patterns of neural coding in response to corresponding exterior forms of stimulus. The performance of SNC is extremely dependent on brain-inspired models. However, the bio-rationality of a brain-inspired model remains inadequate. The purpose of this paper is to investigate a more bio-rational brain-inspired model and the SNC of this brain-inspired model. In this study, we construct a complex spiking neural network (CSNN) in which its topology has the small-word property and the scale-free property. Then, we investigated the SNC of CSNN under various strengths of various stimuli and discussed its mechanism. Our results indicate that (1) CSNN has similar neural time coding under same kind of stimulus;(2) CSNN has significant SNC based on time coding under various exterior stimuli;(3) our discussion implies that the inherent factor of SNC is synaptic plasticity.
Specific neural coding is the key to achieving advanced cognitive function in a bio-brain, which can form an identifying coding pattern for external stimulation. The performance of specific neural coding depends extre...
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Specific neural coding is the key to achieving advanced cognitive function in a bio-brain, which can form an identifying coding pattern for external stimulation. The performance of specific neural coding depends extremely on brain-like models. However, the bio-interpretability of the topology of a brain-like model is still insufficient. The purpose of this paper is to investigate a more biological interpretative brain-like model verified by the performance of specific neural coding. In this study, we used the topology constrained by human brain functional magnetic resonance imaging (fMRI) to construct a new spiking neural network (SNN) as a brain-like model called fMRI-SNN. In the fMRI-SNN, the nodes are Izhikevich neuron models, and the edges are synaptic plasticity models with time-delay. Then, we investigated the specific neural coding of fMRI-SNN, and discussed its mechanism. Our results indicated that: (i) fMRI-SNN has obvious specific neural coding based on time coding for different external stimulations. Furthermore, our discussion on relevance analysis implies that the intrinsic element of specific neural coding is synaptic plasticity. (ii) The specific neural coding of fMRI-SNN outperforms that of scale-free SNN and small-world SNN. Furthermore, our discussion on dynamic topological characteristics implies that the network topology is an element that impacts the performance level of the specific neural coding. (iii) Taking a speech recognition task as a case study, the performance of fMRI-SNN outperforms that of scale-free SNN and small-world SNN in terms of speech recognition accuracy.
By demand enhancement in the cellular communications, critical needs for the next generation of the phased array antenna are grown. In this article, the time-modulated array is combined with the relatively recent codi...
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By demand enhancement in the cellular communications, critical needs for the next generation of the phased array antenna are grown. In this article, the time-modulated array is combined with the relatively recent coding metasurface theory to introduce time-coding metasurface antenna (TCMA). This innovative antenna design facilitates flexible spatial modulation of electromagnetic (EM) waves without using complicated feeding network and traditional phase shifter. Hence, it enables the generation of multiple concurrent but independent-directive high-gain beams to cover a predefined angular range, unlike the conventional array antenna which has its single-directive beam that covers only one user at cellular communication. The article focuses on the theoretical analysis of a TCMA designed with embedded 2-bit p-i-n diodes, which is also successfully fabricated. Applying various time sequences, the proposed array showcases the ability to steer beams at the center frequency and concurrently generate multiple beams at different frequencies, each with specific radiation angles. The flexibility and capability of the proposed metasurface antenna is used for different communication applications.
This paper investigates the application and performance improvement of MIMO Space time Block coding (STBC) for Physical Layer Security. The paper analyzes a Precoder Matrix Index (PMI) based scheme called Private Rand...
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ISBN:
(纸本)9781728104577
This paper investigates the application and performance improvement of MIMO Space time Block coding (STBC) for Physical Layer Security. The paper analyzes a Precoder Matrix Index (PMI) based scheme called Private Random Pre-coding (PRP). Key-based Physical Layer Security protects against eavesdroppers in wireless communication links, invaluable in emerging SG and IoT networks. This paper derives improvements in PRP based on STBC. Also presented are simulation results which show as much as 7 dB improvement in Key bit Error Rate performance vs SINR of the enhanced PRP-STBC scheme for a 1-bit codebook at the cost of decreased transmission rate. In addition, the paper derives a closed form expression for the Key bit Error Rate for both the PRP and enhanced PRP-STBC schemes as a function of dense SG cellular geometries. Furthermore, we present the effective information rate of the PRP key based communication framework in low SNR scenarios.
In this paper, we analyze the diversity-multiplexing tradeoff (DMT) performance of opportunistic relaying coded cooperation (ORCC) and distributed space-time coding coded cooperation (DSTCCC) with arbitrary number of ...
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In this paper, we analyze the diversity-multiplexing tradeoff (DMT) performance of opportunistic relaying coded cooperation (ORCC) and distributed space-time coding coded cooperation (DSTCCC) with arbitrary number of relays. Exact DMT curves are derived for two scenarios, i.e., when the source is included in cooperation (denoted by S1) or not (denoted by S2), by formulating the problem as linear optimization problem. The DMT curves of ORCC and DSTCCC are found to be identical for S1 (or S2), and S1 has better DMT performance than S2. Numerical results are provided to illustrate the analysis as well.
In this paper, we consider two-way full-duplex (FD) relay networks, which allow relaying communications in both directions at the same time and over the same frequency band. We propose a distributed space-time coding ...
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ISBN:
(纸本)9781479959532
In this paper, we consider two-way full-duplex (FD) relay networks, which allow relaying communications in both directions at the same time and over the same frequency band. We propose a distributed space-time coding scheme, which we call SC-DSTC (Self-Coded Distributed Space-time coding), where the main idea is to perform convolutional encoding at the relay node and form a distributed linear convolutional space-time code (DLC-STC) together with the direct link. The convolutional code at the relay is realized by using part of the residual loop interference (RLI), which produces an automatic convolutional encoder. The amplifying factor is optimized when the loop channel information is imperfect. Simulation results show that the proposed SC-DSTC scheme can achieve asynchronous full cooperative diversity and is robust to the error of the loop channel information.
MIMO system is the basic principle of hollow when encoding, and then discussed emphatically in the MIMO system of FSO practical two space-time coding, OSTBC coding with REP coding. Introduces the basic principle of tw...
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MIMO system is the basic principle of hollow when encoding, and then discussed emphatically in the MIMO system of FSO practical two space-time coding, OSTBC coding with REP coding. Introduces the basic principle of two kinds of coding, and in the case of the known a priori knowledge of channel was deduced BER expression, can be seen from the expression of conditional probability, REP space-time coding is superior to OSTBC space-time coding. After using Monte Carlo method of numerical simulation obtained the conclusion of the expression of conditional probability are verified.
In this work we propose an adaptive buffer-aided space-time coding scheme for cooperative wireless networks. A maximum likelihood receiver and adjustable code vectors are considered subject to a power constraint with ...
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In this work we propose an adaptive buffer-aided space-time coding scheme for cooperative wireless networks. A maximum likelihood receiver and adjustable code vectors are considered subject to a power constraint with an amplify-and-forward cooperation strategy. Each multiple-antenna relay is equipped with a buffer and is capable of storing the received symbols before forwarding them to the destination. We also present an adaptive relay selection and optimization algorithm, in which the instantaneous signal to noise ratio in each link is calculated and compared at the destination. An adjustable code vector obtained by a feedback channel at each relay is employed to form a space-time coded vector which achieves a higher coding gain than standard schemes. A stochastic gradient algorithm is developed to compute the parameters of the adjustable code vector with reduced computational complexity. Simulation results show that the proposed buffer-aided scheme and algorithm obtain performance gains over existing schemes.
Reconfigurable intelligent surfaces (RISs) offer an entirely new route to alter the propagation properties of electromagnetic waves and thus control their reflection, refraction, and scattering features in arbitrary m...
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Reconfigurable intelligent surfaces (RISs) offer an entirely new route to alter the propagation properties of electromagnetic waves and thus control their reflection, refraction, and scattering features in arbitrary manners. Such physical attributes are perceived to bring about fundamental influence on the modern wireless communication system due to the possibilities to establish artificial and controllable propagation environments for radio signals, which no longer rely on the complex encoding, decoding, and other signal processing techniques. Recent studies reveal that the wave manipulation is not the only skill of the RISs. With the rapid developments of space-time digital metasurface and information metasurface, there has been increasing attention focused on the information manipulation via these artificial surfaces. In this article, we provide an overview of the theoretical models of the space-time digital metasurface and information metasurface, the mechanisms of wavefront shaping, and the signal modulations in space and time domains during the wave-matter interactions. We will also address some practical issues during implementations of the reconfigurable intelligent metasurfaces and the associated hardware architectures at microwave frequencies to realize simplified radio frequency transmitters. Several modulation schemes and the corresponding demonstration systems are introduced to illustrate the powerful abilities of the reconfigurable intelligent metasurfaces. Potential research directions of this technique are briefly discussed for their potential applications in future wireless networks.
In this study, the authors evaluate the outage probability performance of an amplify-and-forward cooperative relay network where the relays are equipped with cognitive radios. When the number of available relays is mo...
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In this study, the authors evaluate the outage probability performance of an amplify-and-forward cooperative relay network where the relays are equipped with cognitive radios. When the number of available relays is more than four the authors use the channel conditions in order to select the best four cognitive relays from a set of M cognitive relay nodes and then they are used for cooperation between the source and the destination nodes. Expressions for outage probability are determined for a frequency flat Rayleigh-fading environment from the received signal-to-noise ratio with perfect and imperfect spectrum acquisition. In addition, a modified distributed quasi-orthogonal space-time block coding scheme with increased code gain distance is considered for use within the proposed cognitive relay network. To utilise the available spectrum opportunities with the modified quasi-orthogonal space-time block code, the code matrix can be adapted to the number of available relays. Simulation results show that the four relay selection improves the system performance. This is confirmed by the outage probability analysis. The simulations also show that the modified code can significantly enhance the performance of the system and improve the reliability of the link as compared with the conventional distributed quasi-orthogonal space-time block coding.
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