Nano Communication Networks最新文献

Molecular communication (MC) is a recent novel communication paradigm, which could enable revolutionary applications in the fields of medicine, military, and environment. Inspired by nature, MC uses molecules as information carriers to transmit and receive data. Concentration-encoded molecular communication (CEMC) is an information encoding approach, where the information is encoded in the concentration of the transmitted molecules. In this paper, we propose a machine learning (ML)-based CEMC system. In particular, we propose a modulation scheme named concentration position-shift keying (CPSK), which encodes information as the position of the transmitted molecular concentration. After passing through a diffusion-based channel, the molecules are captured via a ligand–receptor binding process (LRBP) at the nanoreceiver. Then, a ML-based approach is employed to decode the data bits. From numerical simulations, it has been shown that increasing the transmission time and using 4-ary CPSK would enhance the communication performance of the proposed ML-based CEMC system. In addition, we found that the ML receiver mitigates the bias effect and reduces inter-symbol interference (ISI) of the diffusion-based molecular channel. As a result, the proposed ML-based receiver shows better performance than the conventional maximum-likelihood (MLE) receiver.

The ever-increasing capacity demand (up to Tbps in the foreseeable future) in wireless connectivity can supposed be satisfied by terahertz communications in the band from 100 GHz to 10 THz. This has been studied over short channel distances in laboratories using higher order modulation formats (QPSK, QAM). However, only very few reports on the THz channel performance in outdoor adverse weathers conditions are available due to the involved experimental difficulties. In this article, we report the performance of terahertz channels in emulated rain by utilizing a broadband pulse source and a 16-QAM modulated data stream. We observe that, a not precisely known of raindrop size distribution can be a major source of uncertainty for theoretical precipitation of power attenuation and bit error rate (BER). We also find that the channel degradation in rain is mainly due to power attenuation.

Today, communication links and networks are essential in transmitting data and information. Moreover, information sharing in communication devices and networks has become necessary, routine, and unavoidable. Consequently, designing and manufacturing high-speed nano-scale devices with ultra-low power consumption is very important. Among the emerging paradigms in nanotechnologies, quantum-dot cellular automata (QCA) is very popular in communication sciences. In the present study, we optimize the design and implementation of a QCA crossbar switch and use it in transmitter and receiver circuits. Subsequently, a circuit-switched network in QCA technology is implemented using these devices. All the designed circuits are coplanar with the minimum number of cells, optimal area and latency, and low power consumptions, which employ standard QCA design rules and show superiority and advantages compared to the previous designs.

Quantum-dot cellular automata (QCA) is a new technology to replace CMOS technology in digital circuits. This replacement is necessary since further miniaturization of CMOS devices has posed serious challenges. In this paper, an optimized 1:2 demultiplexer (1:2 DEMUX) as a tree network switch is proposed. The tree network is examined, and the switches, which are the main components of the network, are used for routing. The proposed 1:2 DEMUX uses a rotated majority gate (RMG) based on QCA technology. According to the evaluation of the proposed 1:2 DEMUX circuit, 16 QCA cells are used with a total area and latency of 0.$02\mu m$² and 0.25 clock cycles, respectively. A comparison with the best reported similar designs shows 15.78% improvement in the complexity, cell area, and area usage of the proposed 1:2 DEMUX. Another parameter that plays a very important role in QCA circuits is energy consumption, which can be measured with QCAPro software. In the proposed DEMUX circuit, the values of energy dissipation for 0.5, 1, and 1.5 E${}_k$ are 16.75, 24.84, and 34.6 meV respectively. The proposed router is the first of its kind that uses QCA-based DEMUX. This router has 146 cells, and its total area and latency are equal to 0.$25\mu m$² and 0.75 clock cycles, respectively.

A tunable terahertz (THz) slotted monopole antenna is implemented with self-diplexing capability. The radiating arms of antenna are filled with the graphene strips. The variation in electrical parameters of graphene alters the surface current distribution in the radiating arms which results in tuning the antenna response through individual input ports. Antenna operates in frequency range 4.75–5.34 $THz$ and 5.57–6.76 $THz$ with the application of input at port-1 and 2, respectively which can further be tuned with the reported biasing schemes. The antenna structure utilizes the orthogonal radiating slots which provides high isolation more than 150 dB between the ports in compact antenna geometry. An electrical equivalent circuit is prepared to verify the antenna operation. In addition, antenna offers the peak gain 3.83 dBi at port-1 and 6.06 dBi at port-2 in the operating passband along with the efficiency of more than 80%. Antenna provides the compact geometry with tunable self-diplexing capability and can be suitable for future wireless applications requiring the simultaneous transmit and receive systems.

Quantum-dot cellular automata (QCA) is a domain coupling nano-technology that has drawn significant attention for less power consumption, area, and design overhead. It is able to achieve a high speed over the CMOS technology. Recently, the tendency to design reversible circuits has been expanding because of the reduction in energy dissipation. Hence, the QCA is a crucial candidate for reversible circuits in nano-technology. On the other hand, the addition operator is also considered one of the primary operations in digital and analog circuits due to its wide applications in digital signal processing and computer arithmetic operations. Accordingly, full-adders have become popular and extensively solve mathematical problems more efficiently and faster. They are one of the essential fundamental circuits in most digital processing circuits. Therefore, this article first suggests a novel reversible block called the RF-adder block. Then, an effective reversible adder design is proposed using the recommended reversible RF-adder block. The QCAPro and QCADesigner 2.0.3 tools were employed to assess the effectiveness of the suggested reversible full-adder. The outcomes of energy dissipation for the proposed circuit compared to the best previous structure at three different tunneling energy levels indicate a reduction in the power consumption by 45.55%, 38.82%, and 34.62%, respectively.

As the potential of molecular communication via diffusion (MCvD) systems at nano-scale communication increases, designing molecular schemes robust to the inevitable effects of molecular interference has become of vital importance. There are numerous molecular approaches in literature aiming to mitigate the effects of interference, namely inter-symbol interference. Moreover, for molecular multiple-input–multiple-output systems, interference among antennas, namely inter-link interference, becomes of significance. Inspired by the state-of-the-art performances of machine learning algorithms on making decisions, we propose a novel approach of a convolutional neural network (CNN)-based architecture. The proposed approach is for a uniquely-designed molecular multiple-input–single-output topology in order to alleviate the damaging effects of molecular interference. In this study, we compare the performance of the proposed network with that of an index modulation approach and a symbol-by-symbol maximum likelihood estimation and show that the proposed method yields better performance.

The frequency ratio of higher to lower order mode can be electronically tuned in a terahertz (THz) antenna with metallic radiator using a graphene loop. Antenna is designed with slotted metallic radiator to obtain the dual-band response with fundamental and second order transverse magnetic mode providing the directional and bi-directional radiation pattern in the lower and upper band, respectively. The insertion of graphene loop and varying its chemical potential (${\mu }_c$) provides two resonances until $0.4\mathrm{eV}$ and four resonances for further greater values of ${\mu }_c$. The desired impedance matching can be achieved at the frequencies of any two resonances at a time by selecting an appropriate value of ${\mu }_c$. Antenna can operate with higher/lower order mode centred at frequency 3.77/3.02 THz and 4.39/2.86 THz for the values of ${\mu }_c$ as 0.9 and $0.3\mathrm{eV}$ , respectively. The frequency ratio of higher to lower order mode can be tuned within the range of 1.22–1.59 with the variation in ${\mu }_c$. Also, application of graphene loop confines the radiated power in a single direction at the frequency of higher order mode making the radiation pattern consistent. Antenna can be utilized in future THz wireless applications which require the utilization of adjacent channels with different frequencies in communication. Also, a two-port antenna is designed which can offer the tunable multi-input–multi-output (MIMO) and self-diplexing capability with pattern diversity. The MIMO parameters; envelope correlation coefficient (ECC) and diversity gain (DG) is evaluated and their values are found within acceptable limits as ECC$<0.06$ and DG$>9.9$ in the operating bands.

In this paper, a circular-shaped microstrip feed wideband THz antenna with a small dimension of 480 × 480 $\times$ $150\mu m$³ is presented on a gold-plated diffused quartz substrate with a relative permittivity of 3.50. It has an impedance operational bandwidth of 0.51-1.46 THz (80.76%) with a peak gain of 10.16 dBi. Throughout the desired bandwidth, radiation efficiency is more than 70%. This single-element antenna is transformed into a two-element MIMO antenna using a butterfly-shaped decoupling structure that included an electromagnetic coupling structure and a metasurface absorber to increase isolation and diversity characteristics along with impedance bandwidth 0.4-2.0 THz. Return loss, gain, radiation efficiency, co-cross E and H-polarization, electric field, magnetic field, current density, SAR, and diversity parameters such as Envelope Correlation Coefficient (ECC), Directive Gain (DG), Total Active Reflection Coefficient (TARC), and Channel Capacity Loss (CCL) are all within acceptable limits for Nano wireless applications. The proposed wideband THz MIMO antenna can also be used as a sensor to measure the proportion of crystallized sugar (C₁₂H₂₂O₁₁) and salt (NaCl) in water. The fields in which this antenna has applications include 6G, imaging, 3D printing, THz-wave radar, healthcare, liquid sensors with excellent sensitivity, and astronomy radiometric.