In this paper, an optimized codebook design for a non-orthogonal multiple access scheme, called sparse code (SCMA), is presented. Unlike the low density signature (LDS) systems, in SCMA procedure of bits to QAM symbol mapping and spreading are combined together, incoming directly mapped codewords sets. Each layer or user has its dedicated codebooks all different. An improved method based on star-QAM signaling constellations proposed here designing codebooks. It demonstrated that new can...

In this paper, a novel codebook design method for sparse code multiple access (SCMA) is proposed and an analytical framework to evaluate the bit error rate (BER) performance developed. particular, meet criteria based on pairwise probability, with large minimum Euclidean distance employing star quadrature amplitude modulation signal constellations designed. addition, aid of phase distribution presented SCMA constellations, BER system over downlink Rayleigh fading channel obtained in...

As 5G networks are being rolled out in many different countries nowadays, the time has come to investigate how upgrade and expand them toward 6G, where latter is expected realize interconnection of everything as well development a ubiquitous intelligent mobile world for life. To enable this epic leap communications, article provides an overview outlook on application sparse code multiple access (SCMA) 6G wireless communication systems, which emerging disruptive non-orthogonal (NOMA) scheme...

In this paper, motivated by the fact that precisely positioning a flying unmanned aerial vehicle (UAV) passive radio frequency (RF) measurements are being troubled extreme non-line-of-sight (NLOS) environments, we propose 3D joint time difference of arrival (TDOA) and angle (AOA) NLOS localization method for UAVs using three receivers. Compared with existing schemes based on received signal strength (RSS), TDOA, (TOA), AOA methods, advantage proposed is do not need many receivers or priori...

Citation analysis is an active area of research for various reasons. So far, statistical approaches are mainly used citation analysis, which does not look into the internal context citations. Deep may reveal interesting findings by utilizing deep neural network algorithms. The existing scholarly datasets best suited but lack context, intent, and section information. Furthermore, too small to be with learning approaches. For intent must have a labeled different classes. Most either do...

This paper considers a novel scenario, where physical layer security issue is studied in unmanned aerial vehicles (UAVs)-assisted cognitive relay system. A secondary vehicle (SUAV) delivers information from multiple Internet of things (IoT) devices to user (SU) under the spectrum sharing with primary users (PUs). In processing transmission SUAV relay, eavesdropper (SE) wiretaps transmitted by UAV imperfect location information. order confuse SE, friendly jammer employed transmit jamming...

Employing massively distributed antennas brings radio access points (RAPs) closer to users, thus enables aggressive spectrum reuse that can bridge gaps between the scarce resource and extremely high connection densities in future wireless systems. Examples include cloud network (C-RAN), ultra-dense (UDN), cell-free massive multiple-input multiple-output (MIMO) These systems are usually designed form of fiber-wireless communications (FWC), where or RAPs connected a central unit (CU) through...

Photodetectors (PDs) are critical parts of visible light communication (VLC) systems for achieving efficient photoelectronic conversion and high-fidelity transmission signals. Antimony sulfide (Sb2S3) as a nontoxic, high optical absorption coefficient, low-cost semiconductor becomes promising candidate applications in VLC systems. Particularly, Sb2S3 PDs were verified to have significantly weak detection ability the region. However, response speed with existing device structures is still...

In this letter, the average bit error rate (BER) performance of sparse code multiple access (SCMA) systems with codebooks based on star quadrature amplitude modulation (star-QAM) signaling constellations over additive white Gaussian noise channel is analyzed and evaluated. Motivated by fact that phase rotation plays an important role in designing thus can significantly affect BER SCMA system, we derive a theoretical expression for statistics angle constellations. Numerical simulation results...

Abstract Every year, around 28,100 journals publish 2.5 million research publications. Search engines, digital libraries, and citation indexes are used extensively to search these When a user submits query, it generates large number of documents among which just few relevant. Due inadequate indexing, the resultant largely unstructured. Publicly known systems mostly index papers using keywords rather than subject hierarchy. Numerous methods reported for performing single-label classification...

Abstract Unmanned aerial vehicles (UAVs) are widely used in wireless communication networks due to their rapid deployment and high mobility. However, practical scenarios, the existence of obstacles eavesdroppers will seriously interfere with quality UAV network produce a security risk. Thus, this paper combines reconfigurable intelligent surface (RIS) technology UAVs build secure network. Normally, rotary‐wing (labeled as UAV‐S) acting base station sends information signals legitimate user...

The combination of multiple-input multiple-output (MIMO) and sparse code multiple access (SCMA), referred to as MIMO-SCMA, can be leveraged achieve high spectrum efficiency provide massive connectivity for future machine -type communication networks. This paper aims design enhanced codebooks MIMO-SCMA by jointly combining frequency spatial diversity over Rayleigh fading channels. First, based on the pairwise error probability (PEP), novel codebook criteria have been presented, namely hybrid...

As an essential technology for spectrum sensing and dynamic access, automatic modulation classification (AMC) is a critical step in intelligent wireless communication systems, aiming at automatically recognizing the schemes of received signals. In practice, AMC challenging due to influence environment signal parameters, such as unknown channels, noise, symbol rate, length, sampling frequency. this survey, we investigated series typical methods, including key technology, performance...

Sparse code multiple access (SCMA) is a promising multiuser communication technique for the enabling of future massive machine-type networks. Unlike existing codebook design schemes assuming uniform power allocation, we present novel class SCMA codebooks which display imbalance among different users downlink transmission. Based on Star-QAM mother constellation structure and with aid genetic algorithm, optimize minimum Euclidean distance (MED) product (MPD) proposed codebooks. Numerical...

Cell instance segmentation (CIS) via light microscopy and artificial intelligence (AI) is essential to cell gene therapy-based health care management, which offers the hope of revolutionary care. An effective CIS method can help clinicians diagnose neurological disorders quantify how well these deadly respond treatment. To address task challenged by dataset characteristics such as irregular morphology, variation in sizes, adhesion, obscure contours, we propose a novel deep learning model...

Due to the low efficiency of energy harvest (EH) for traditional wireless powered communication network (WPCN), we propose a scheme based on unmanned aerial vehicle (UAV)-enabled WPCN, which can greatly improve EH problem. In this paper, UAV trajectory, time allocation, transmit power UAVs, scheduling information transfer (WIT) and (WPT) are jointly optimized minimize whole consumption. To solve formulated non-convex problem with multiple constraints attain locally optimal solution, an...

At present, the number of incoming devices and mobile data traffic has seen explosive growth, spectrum resources are difficult to meet increasing demand. The traditional centralized management model suffers from low utilization, high maintenance costs, security issues. decentralized secure nature blockchain technology is a natural advantage in solving problems faced by current model. However, when introducing into management, it faces such as latency resource consumption. In this letter, we...

We study the optimum designs of downlink user-centric ultra-dense Internet Things (IoT) networks with fiber-wireless communications (FWCs). A large number low power radio access points (RAPs) are densely deployed in network to provide service spatially distributed IoT physical devices (PDs). The RAPs connected a central unit (CU) through optical fiber (OF) front-hauls. Radio-frequency-over-fiber (RFoF) is employed front-hauls reduce RAP complexity, cost, and energy consumption. With RFoF...

Abstract This paper studies a multi‐unmanned aerial vehicle (UAV) assisted mobile edge computing (MEC) system, where multiple UAVs equipped with MEC server are deployed to provide offloading services for ground users limited local resources. Specifically, each user divides its tasks into two parts: one part is offloaded the associated UAV calculation, and remaining calculated locally. It aimed minimize weighted energy consumption of all by jointly optimizing trajectory, scheduling, central...

In this paper, an optimized codebook design based on rotated angles and extrinsic information transfer (EXIT) chart for a non-orthogonal multiple access scheme, called irregular sparse code (IrSCMA), is presented. Unlike regular SCMA, in IrSCMA, the defined degree of layer's resource nodes different, which beneficial to system performance.It demonstrated that new can greatly improve BER performance especially when signal-to-noise ratio(SNR) high, without sacrificing low detection complexity,...

In this paper, the energy efficient virtual machine (VM) placement and resource allocation problem for mobile edge computing (MEC) system is explored. Particularly, we develop an optimization framework of consumption minimization offloading by jointly optimizing VM matrix number physical machines (PMs). To resolve problem, transform into a non-uniform weighted hypergraph model. model, weight hyperedge defined as negative accumulated at instances hosted one PM. Based on matching algorithm...

In this letter, the average spectral efficiency (SE) of sparse code multiple access (SCMA) systems with adaptive codebooks based on star-QAM signaling constellations is analyzed and evaluated. Motivated by fact that different power allocations have effects SE in SCMA systems, we propose three allocation schemes to maximize existing theoretical bit error rate (BER) expression. addition, compare between OFDMA under same scheme. Numerical analytical results corroborate proposed schemes.

This paper proposes some low complexity algorithms for active user detection (AUD), channel estimation (CE) and multi-user (MUD) in uplink non-orthogonal multiple access (NOMA) systems, including single-carrier multi-carrier cases. In particular, we first propose a novel algorithm to estimate the users channels based on complex alternating direction method of multipliers (ADMM), where fast decaying feature non-zero components sparse signal is considered. More importantly, reliable estimated...