Nano Communication Networks最新文献

In the evolving landscape of terahertz communication, the behavior of channels within indoor environments, particularly through glass doors, has garnered significant attention. This paper comprehensively investigates terahertz channel performance under such conditions, employing a measurement setup operational between 113 and 170 GHz. Analyzing scenarios frequently induced by human activity and environmental factors, like door movements, we established a comprehensive theoretical model. This model seamlessly integrates transmission, reflection, absorption, and diffraction mechanisms, leveraging the Fresnel formula, multi-layer transmission paradigm, and knife-edge diffraction theory. Our experimental results and theoretical predictions harmoniously align, revealing intricate dependencies, such as increased power loss at higher frequencies and larger incident angles. Furthermore, door interactions, whether opening or oscillations, significantly impact the terahertz channel. Notably, door edges lead to a power blockage surpassing the transmission loss of the glass itself but remaining inferior to metallic handle interferences. This paper's insights are pivotal for the design and fabrication of terahertz communication systems within indoor settings, pushing the boundaries of efficient and reliable communication.

A nanonetwork is a multi-hop network composed of tiny communicating components, whose energy budget is rather limited. A method to reduce the energy used by nodes is to reduce the number of packets transmitted. In this article, we propose a dynamic 3D scheme to reduce the number of forwarders during routing. In this scheme, potential forwarders are found on a ring around transmitter nodes. We analyze the effectiveness of our 3D scheme for four routing protocols in multi-source scenarios. We analyze its memory cost, both theoretically and by simulation. Results show that the proposed scheme works in 3D, and reduces the number of forwarders while maintaining almost the same packet delivery ratio.

To meet the needs of the market launch, placement and routing(P&R) algorithms for conventional circuits have started to adopt a hierarchical design, divide and conquer philosophy for the layout of VLSI circuits. Quantum-dot cellular automata (QCA) circuits are considered a solution to overcome the limitations of Moore’s Law. However, the current automated design of QCA circuits is still in its preliminary stages. This paper uses a hierarchical structure, which borrows from traditional circuits that should be laid out in large-scale circuits, to hierarchically process QCA circuits, laying them out layer by layer while using the A* algorithm for wiring to find feasible solutions. The algorithm is implemented using the C++ programming language, and simulation results verify the correctness of the algorithm.

This paper reviews the effect of graphene on antenna characteristics for wireless communication based on fifth generation (5 G) and sixth generation (6 G). The integration method of graphene material on antenna structure in the microwave, millimetre wave, and terahertz bands affects various characteristics. By analysing all the graphene antennas using two types of integration methods:graphene as the only radiating element and graphene-hybrid, different improvements in antenna characteristics are collected, including impedance bandwidth, radiation pattern, antenna gain, antenna efficiency, tuning capability in resonant frequency as well as radiation pattern, reconfigurable capability, and beam scanning capability. This review found that a graphene antenna that implements hybrid integration in antenna structure at 5 G and 6 G frequency bands shows some of these characteristics, such as good tunable resonant frequency, wide impedance bandwidth, gain improvement, mutual coupling reduction, changing of polarisation, direction of main beam, variation of gain, axial ratio, and efficiency when direct current (DC) biasing or resistance is applied and changed. The graphene antenna that uses graphene as the only radiating patch has a moderately biased effect on microwave frequency with respect to the antenna's performance in the terahertz range because of different behaviour of graphene's conductivity, but it also depends on many factors such as frequency, geometry, and specifications. From this review, it appears that the presence of graphene in the antenna will produce better characteristics. It is an opportunity for antennas for future wireless generation by recommending graphene as the hybrid integration method in the antenna structure.

The application of DNA monitoring has recently expanded into the information technology realm of DNA computing and storage systems, leveraging its capabilities for molecular computing and high-density data storage. Essential to this advancement are multi-color fluorescent signals attached to informational DNA, enabling simultaneous multidata reading in the DNA memory or storage system. Various fluorescent detection techniques, such as real-time polymerase chain reaction, next-generation sequencing, and fluorescence resonance energy transfer, have been investigated for DNA reactions and sequence data. Although proximity (less than 10 nm) between different fluorescent signals can lead to interference, controlling the distance of fluorescent molecules attached to DNA is a feasible solution. This study demonstrates a DNA molecular memory system using multiple fluorescent molecules. We examined the independent hybridization of three different fluorescent DNA molecules to DNA templates with three sites for fluorescent attachment on 17 nt DNAs. The study focused on two multi-bit DNA molecules hybridized to the template DNA, assessing their fluorescence emission intensities at various excitation wavelengths. Two multi-bit DNA molecules, which were hybridized onto the template DNA, were investigated for fluorescence emission intensities by various excitation wavelengths. Although the emission intensities of the two multi-bit DNA molecules were not significantly increased by another fluorescent molecule, each excitation wavelength has provided more effective emission intensity levels for DNA signal detection. Furthermore, we developed a three-bit DNA molecular memory system using triple-level DNA molecules. These multi-color DNA systems could be extended to arithmetic and logical computing.

The occupied area, power consumption, and delay are the most crucial and critical factors in constructing integrated circuits. Due to the reduced occupied area, highly low power consumption, and extremely high speed of quantum-dot cellular automata (QCA) technology, it is one of the finest alternatives to complementary metal–oxide–semiconductor (CMOS) technology for nanoscale construction of circuits. On the other hand, fault tolerance becomes crucial in QCA due to the inherent sensitivity of quantum dots to various sources of errors and faults. These errors can arise from environmental disturbances, manufacturing imperfections, thermal fluctuations, and other factors. The presence of defects or faults can significantly impact the functionality and accuracy of QCA systems, leading to incorrect computation or signal corruption. To address these challenges, fault-tolerant structures are designed in QCA systems. These structures are specifically engineered to detect, tolerate, and mitigate the effects of faults, thereby enhancing the reliability and robustness of QCA-based computation. Fault-tolerant designs aim to ensure that the system can continue to operate correctly even in the presence of defects or faults. In QCA, proposed a fault-tolerant majority gate is necessary to ensure reliable computation in the presence of defects or faults. The fault-tolerant majority gate is a fundamental component in digital logic circuits, and it plays a crucial role in performing computations. It takes multiple input signals and produces an output based on the majority of those inputs. In classical computing, the majority gates are typically implemented using transistors. Therefore, this paper introduces a new and efficient fault-tolerant 3-input majority voter (FT MV3) using 11 simple and rotated cells in the QCA technology, which is 100% and 90.47% tolerant against single-cell and double-cell omission defects. The recommended FT MV3 gate verification is confirmed using some physical proofs. Afterward, to illustrate the performance of the introduced gate, three fault-tolerant computational circuits, including multiplexer, adder and ALU, are presented using the introduced FT MV3 gate. The comparison of the proposed fault tolerant ALU to the best coplanar design shows a 28.80% and 34.01% reduction of cell count and occupied area, respectively. All circuits are simulated using QCADesigner 2.0.3 software.

In this paper, a multiband THz Multi-Input Multi-Output (MIMO) antenna is designed with dimensions of 80×100×10.8μm³. The antenna is made-up on a gold-plated Arlon AD410 substrate with a relative permittivity of 4.1.It operates at three resonant frequencies, namely 1.45THz, 2.25THz, and 3.25THz, achieved through the integration of Complementary Split-Ring Resonator (CSRR) and Substrate Integrated Waveguide (SIW) technologies. The two-element MIMO configuration of the antenna ensures exceptional performance, offering high throughput with data rates of 25.23Gbps for the Quadrature Phase Shift Keying (QPSK) scheme and 56.68Gbps for the 16-Quadrature Amplitude Modulation (QAM) scheme. It also exhibits remarkable channel capacity, approximately 8.2bps/Hz at Signal-to-Noise Ratio (SNR) = 20dB, surpassing the capabilities of single-element antennas. Moreover, it demonstrates excellent diversity performance for judging the MIMO antenna performance. This is evident through the following key metrics: Envelope Correlation Coefficient (ECC) < 0.02, indicating that less than 1 % of power is transferred from the excited antenna to the second 50Ω terminated antenna when antenna-1 is excited; Directive Gain (DG) >9.95dB; Total Active Reflection Coefficient (TARC) < -10dB, ensuring that a minimum of 90 % of the power is delivered to the patch port; and Channel Capacity Loss (CCL) < 0.35 bits/sec/Hz, guaranteeing reliable wireless communication. The antenna boasts peak gains of 3.83dBi, 4.06dBi, and 6.82dBi at 1.45THz, 2.25THz, and 3.25THz, respectively, along with a radiation efficiency of approximately 37, 58, and 51 % at the corresponding frequencies. Notably, the first two bands (1.34-1.51THz and 2.20-2.28THz) exhibit narrow bandwidths with quality factors above 80, making them particularly suitable for sensing applications in biomedical. Band-1 offers an average sensitivity of 3222.22 GHz/RIU and an FOM of 17.89, while Band-2 provides an average sensitivity of 2578.68 GHz/RIU and an FOM of 14.38. These characteristics make it well-suited for near-field Nano-communications and sensing applications.

This paper reports a subwavelength grating (SWG) based multiplexer (MUX) on a silicon photonics platform capable of multiplexing three transverse electric modes. The designed MUX is simulated using a commercial 3D finite-difference time-domain solver and shows broadband operation over the whole C and L optical telecom bands from 1530 nm to 1625 nm wavelength range. The effective indices of the Bloch modes in the SWG waveguides are extracted from the band structure plot. The designed MUX consists of two co-directional coupling regions for fundamental to higher-order mode coupling, with each coupling stage consisting of single-mode and multimode SWG waveguides. The transmission characteristics, viz. transmittance, insertion loss, and return loss, are presented and discussed. The coupling lengths without the tapering regions for TE${}_0$–TE${}_1$ and TE${}_0$–TE${}_2$ mode couplings are $14\mu m$ and $1.48\mu m$, respectively. The transmittance is >78% with the highest insertion loss and return loss of 1.1 dB and –15 dB, respectively. At 1550 nm, the transmission is $>$88%, insertion loss is $<$0.6 dB, and return loss is $<$−15 dB. A uniform under-etch and over-etch of 5 nm are taken for the fabrication tolerance study, which shows a maximum variation of 0.58 dB for the insertion loss with return loss $<$−14.6 dB at 1550 nm. Over the whole simulated range, the insertion loss is $<$1.4 dB, and return loss is $<$−14.6 dB with $\pm$10 nm change in device dimension. A temperature tolerance study with 50 °C and 100 °C rise in temperature has been done, and the device retains its broadband operation over the simulated range. The maximum increase in insertion loss is 0.1 dB for the TE${}_0$–TE${}_2$ coupling, while the overall return loss of the device decreases to $<$−20 dB for the TE${}_0$–TE${}_1$ coupling.

Transmitting information in engineered neural communication systems is a promising solution to delay-sensitive applications for the Internet of Bio-Nanothings (IoBNTs). As widely used in wired and wireless communication systems, introducing multiplexing into neural communication system could improve channel transmission efficiency. In this paper, we model a neural communication system for IoBNTs and propose a neural signal multiplexing scheme for this system, based on frequency-division multiplexing (FDM) principles. The whole system including channel modeling, neural encoding, demultiplexing scheme, and decoding method using kernel density estimation (KDE) are presented. The optimal parameters for KDE and bit error probability are analyzed, and the performance of the proposed strategy is evaluated in terms of error rate and mutual information rate. The work can help researchers better understanding the underlying mechanism of neural multiplexing and pave the way for the implementation of IoBNT applications.

Benefiting by the fast development of nanotechnology, molecular communication (MC) has received great attention in recent years. In many potential applications of MC, such as drug delivery and pollution prevention, it is essential to locate or trace the target. In this paper, we consider a 3D diffusive MC environment consisting of several obstacles, a molecule-releasing source (RS) and a mobile molecule sensor (MS) which aims to find the RS within a time constraint. The problem is reformulated using Markov Decision Process (MDP) and an adaptive multi-layer reward based Q-Learning (AMR-Q Learning) approach is proposed. By exploiting information from the number of received molecules and adaptively setting multi-layer rewards, MS with AMR-Q Learning can find the RS efficiently, unlike the gradient based method which is usually trapped in locally optimal points. Numerical results demonstrate that the proposed AMR-Q Learning approach outperforms existing path-planning schemes with significantly reduced training overhead.