Wireless Information Technology Research Articles

Performance of Orthogonal Frequency Division Multiplexing Based Advanced Encryption Standard

Currently, there are a lot of secure communication schemes have been proposed to hide secret contents. In this work, one of the methods deploying encryption to cipher data is represented. The primary object of this project is applying Advanced Encryption Standard (AES) in communications based Orthogonal Frequency Division Multiplexing (OFDM). This article discusses the security of the method encrypting directly QAM symbols instead of input bit-stream. This leads to improving the security of transmitting data by utilization of authentication key between the mobile and base station. The archived results demonstrate that the performance of the AES-OFDM system is completely acceptable to compare with the criteria for 4G.
 Keywords:
 Orthogonal Frequency Division Multiplexing (OFDM), Advanced Encryption Standard (AES), Quadrature Amplitude Modulation (QAM), Authentication Key, Cellular Network, Encryption, Physical Layer, 4G, LTE.
 References
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 [14] Y. Liang, J. Ren, T. Li, “Secure OFDM System Design and Capacity Analysis Under Disguised Jamming”, in IEEE Transactions on Information Forensics and Security 15 (2020) 738-752.
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Energy Efficiency Optimization in SWIPT Enabled WSNs for Smart Agriculture

Smart agriculture is able to optimize the information resources of agriculture, which can improve the quality and productivity of agricultural products. Wireless sensor networks (WSNs) provide smart agriculture with effective solutions for collecting, transmitting, and processing of information. However, the large number of sensor networks consume too much energy that violates the principle of green communication. Simultaneous wireless information and power transfer (SWIPT) technology utilizes radio-frequency signals to transmit information and provide energy to WSNs, which can extend the lifetime of WSNs effectively. In this article, an architecture design of smart agriculture is first proposed by exploiting the SWIPT. Then, an energy efficiency optimization scheme is studied to achieve green communication, in which the subcarriers’ pairing and power allocation are jointly optimized. The process of communication is divided into two phases. Specifically, in the first phase, source sensor sends information to relay sensor and destination sensor. Relay sensor utilizes a part of the subcarriers to receive the information, and utilizes the remaining subcarriers to collect energy. Destination sensor uses all the subcarriers to receive the information. In the second phase, relay sensor utilizes the energy collected in the first phase to forward the information to destination sensor. An effective iterative optimization algorithm is proposed to resolve the proposed optimization problem through Lagrangian dual function. Simulation results validate that the performance of the algorithm can improve energy efficiency of the system effectively.

JOTE: Joint Offloading of Tasks and Energy in Fog-Enabled IoT Networks

Fog computing is a promising solution to enable delay-sensitive applications in the Internet of Things (IoT). In this article, based on the simultaneous wireless information and power transfer (SWIPT) technology, we investigate the joint offloading of tasks and energy (JOTE) in fog-enabled IoT networks. Specifically, the task node is allowed to offload energy and tasks to multiple neighboring helper nodes in a time-division multiple access (TDMA) manner. When there are no task queues in the nodes, the offloading decision for each task is independent. We first find the offloading strategy to minimize the task execution delay as well as the energy consumption for a specific task and then, analyze the condition under which the JOTE is beneficial. We show that it becomes more and more desirable to offload both the tasks and the energy from the task node as the number of helper nodes gets large. When there are task queues in the nodes, the offloading decision for each task becomes temporally correlated. We then characterize the optimal strategies to offload the tasks and energy jointly over multiple time slots. An online offloading policy based on the Lyapunov optimization is then proposed to minimize the time average expected delay while stabilizing the system operation. Comprehensive numerical results corroborate our theoretical results and demonstrate the superior performance of the proposed JOTE algorithms.

A Comprehensive Survey on Millimeter Wave Communications for Fifth-Generation Wireless Networks: Feasibility and Challenges

Fifth-generation (5G) cellular networks will almost certainly operate in the high-bandwidth, underutilized millimeter-wave (mmWave) frequency spectrum, which offers the potentiality of high-capacity wireless transmission of multi-gigabit-per-second (Gbps) data rates. Despite the enormous available bandwidth potential, mmWave signal transmissions suffer from fundamental technical challenges like severe path loss, sensitivity to blockage, directivity, and narrow beamwidth, due to its short wavelengths. To effectively support system design and deployment, accurate channel modeling comprising several 5G technologies and scenarios is essential. This survey provides a comprehensive overview of several emerging technologies for 5G systems, such as massive multiple-input multiple-output (MIMO) technologies, multiple access technologies, hybrid analog-digital precoding and combining, non-orthogonal multiple access (NOMA), cell-free massive MIMO, and simultaneous wireless information and power transfer (SWIPT) technologies. These technologies induce distinct propagation characteristics and establish specific requirements on 5G channel modeling. To tackle these challenges, we first provide a survey of existing solutions and standards and discuss the radio-frequency (RF) spectrum and regulatory issues for mmWave communications. Second, we compared existing wireless communication techniques like sub-6-GHz WiFi and sub-6 GHz 4G LTE over mmWave communications which come with benefits comprising narrow beam, high signal quality, large capacity data transmission, and strong detection potential. Third, we describe the fundamental propagation characteristics of the mmWave band and survey the existing channel models for mmWave communications. Fourth, we track evolution and advancements in hybrid beamforming for massive MIMO systems in terms of system models of hybrid precoding architectures, hybrid analog and digital precoding/combining matrices, with the potential antenna configuration scenarios and mmWave channel estimation (CE) techniques. Fifth, we extend the scope of the discussion by including multiple access technologies for mmWave systems such as non-orthogonal multiple access (NOMA) and space-division multiple access (SDMA), with limited RF chains at the base station. Lastly, we explore the integration of SWIPT in mmWave massive MIMO systems, with limited RF chains, to realize spectrally and energy-efficient communications.

Review—Machine Learning Techniques in Wireless Sensor Network Based Precision Agriculture

The use of sensors and the Internet of Things (IoT) is key to moving the world’s agriculture to a more productive and sustainable path. Recent advancements in IoT, Wireless Sensor Networks (WSN), and Information and Communication Technology (ICT) have the potential to address some of the environmental, economic, and technical challenges as well as opportunities in this sector. As the number of interconnected devices continues to grow, this generates more big data with multiple modalities and spatial and temporal variations. Intelligent processing and analysis of this big data are necessary to developing a higher level of knowledge base and insights that results in better decision making, forecasting, and reliable management of sensors. This paper is a comprehensive review of the application of different machine learning algorithms in sensor data analytics within the agricultural ecosystem. It further discusses a case study on an IoT based data-driven smart farm prototype as an integrated food, energy, and water (FEW) system.

Wireless power transfer enabled NOMA relay systems: two SIC modes and performance evaluation

In this study, we deploy design and performance analysis in new system model using a relaying model, energy harvesting, and non-orthogonal multi-access (NOMA) network. It is called such topology as wireless powered NOMA relaying (WPNR). In the proposed model, NOMA will be investigated in two cases including single successive interference cancellation (SIC) and dual SIC. Moreover, the simultaneous wireless information and power transfer (SWIPT) technology can be employed to feed energy to relays who intend to serve far NOMA users. In particular, exact outage probability expressions are provided to performance evaluation. The results from the simulations are used to demonstrate the outage performance of the proposed model in comparison with the current models and to verify correct of derived expressions.

Join trajectory optimization and communication design for UAV-enabled OFDM networks

Due to the advantages of high mobility, flexible maneuverability and fast deployment, Unmanned Aerial Vehicle (UAV), which can be usually served as aerial communication platform, not only supports information transmission in the Internet of things (IoT), but also provides reliable power supplement for low-power wireless devices. Considering an UAV-enabled Orthogonal Frequency Division Multiplexing (OFDM) network where subcarriers are divided into two groups for information transmission and energy harvesting, respectively, a joint UAV trajectory optimization and communication design scheme is proposed based on Simultaneous Wireless Information and Power Transfer (SWIPT) technology. Under the given average harvested energy for users, the objective of the scheme is to maximize the average achievable rate for all users by jointly optimizing UAV trajectory, user scheduling, subcarrier and power allocation. To solve the formulated optimization problem, it is transformed into two subproblems to optimize resource allocation and UAV trajectory, respectively. The former is a mixed integer non-convex optimization problem. To solve it, a three-variable alternative iteration algorithm is proposed to obtain the optimal user scheduling, subcarrier and power allocation. Since the latter is non-convex, it can be transformed into convex optimization problem by relaxing objective function and constraint to obtain the optimal trajectory. Simulation results demonstrate that the proposed algorithm has good convergence and the proposed UAV-enabled OFDM network has better performance.

Performance Analysis for MIMO SWIPT Systems with Space-Time Coding

Energy supply is a key factor affecting the normal operation of energy-constrained networks. Simultaneous wireless information and power transfer (SWIPT) technology can be used to obtain a stable and continuous energy source. But SWIPT need to take into account data transmission rate and energy harvesting performance, it is necessary to design a complex physical layer method to improve the energy efficiency of SWIPT system. The paper studies a multiple input multiple output (MIMO) SWIPT system based on space-time coding, the transmitter sends the information using the space-time encoder through multi-antenna transmission, the receiver uses the space-time decoder to decode the information and collect the energy. The expressions of channel capacity and energy harvesting under MIMO are given respectively. The energy harvesting optimization target equation under coding conditions is established. The simulation results show that the using of space-time coding can reduce the data transmission error rate of MIMO SWIPT system and improve the energy harvesting performance of the user terminals.

On Secure Mixed RF-FSO Decode-and-Forward Relaying Systems With Energy Harvesting

In this article, we study the security performance of a mixed radio frequency (RF)-free space optical (FSO) decode-and-forward (DF) relaying system with the simultaneous wireless information and power transfer (SWIPT) technology. The RF channels experience Nakagami- $m$ fading and the FSO channel suffers Malaga turbulence and pointing errors. More precisely, we derive analytical closed-form expressions for the average secrecy capacity and the secrecy outage probability to investigate the security performance of the proposed mixed RF-FSO communication framework with energy harvesting technology.

Performance analysis of a wireless energy‐harvesting cooperative system with precoding spatial modulation

An energy-harvesting decode-and-forward cooperative system over correlated Rayleigh fading channels is investigated. Simultaneous wireless information and power transfer (SWIPT) technology is employed at the relay to improve energy efficiency. To overcome the spatial correlation among the transmit antennas, precoding spatial modulation (PSM) is formulated. The average bit-error probability (ABEP) upper bound is derived and it matches closely with the Monte Carlo simulation results. The influence of the parameters, such as the power-splitting factor and transmit correlation coefficient, on system performance is studied. The results show that the proposed PSM-SWIPT system can achieve better ABEP performance than SM-SWIPT, space shift keying-SWIPT and multiple-input–multiple-output-SWIPT systems under the same spectral efficiency.

An Integrated SEM-Neural Network Approach for Predicting Determinants of Adoption of Wearable Healthcare Devices

The advancement in wireless sensor and information technology has offered enormous healthcare opportunities for wearable healthcare devices and has changed the way of health monitoring. Despite the importance of this technology, limited studies have paid attention for predicting individuals’ influential factors for adoption of wearable healthcare devices. The proposed research aimed at determining the key factors which impact an individual's intention for adopting wearable healthcare devices. The extended technology acceptance model with several external variables was incorporated to propose the research model. A multi-analytical approach, structural equation modelling-neural network, was considered for testing the proposed model. The results obtained from the structural equation modelling showed that the initial trust is considered as the most determinant and influencing factor in the decision of wearable health device adoption followed by health interest, consumer innovativeness, and so on. Moreover, the results obtained from the structural equation modelling applied as an input to the neural network indicated that the perceived ease of use is one of the predictors that are significant for adoption of wearable health devices by consumers. The proposed study explains the wearable health device implementation along with test adoption model, and their outcome will help providers in the manufacturing unit for increasing actual users’ continuous adoption intention and potential users’ intention to use wearable devices.

Joint Source and Relay Beamforming Design in Wireless Multi-Hop Sensor Networks with SWIPT.

We consider a multiple-input multiple-output amplify-and-forward wireless multiple-hop sensor network (WMSN). The simultaneous wireless information and power transfer technology is deployed to potentially achieve an autonomous system. We investigate two practical receiver schemes, which are the power splitting (PS) and the time switching (TS). The power splitting receiver splits received signals into two streams, one for information decoding (ID) and the other for energy harvesting (EH). On the other hand, the time switching receiver only serves in ID mode or energy harvesting mode during a certain time slot. Subject to transmit power constraints and destination harvested energy constraint, we aim to obtain a joint beam-forming solution of source and relay precoders to maximize the maximum achievable rate of the WSN. In order to make the non-convex problem tractable, diagonalization-based alternating optimization algorithms are proposed. Numerical results show the convergence and good performance of the proposed algorithms under both PS and TS protocols.

A NEW PROCESS-ORIENTED AND SPATIOTEMPORAL DATA MODEL FOR GIS DATA

Abstract. With the rapid development of wireless sensor and information technology, there is a trend of transition from "digital monitoring" to "intelligence monitoring" advancing process. The traditional model cannot completely match the dynamic data to accurately describe changes of geographical and environmental changes. In this paper, we try to build a process-oriented and real-time spatiotemporal data model to meet the demands. With various types of monitoring devices, detection methods and the utilization of new technologies, the model can simulate the possible waterlog area in a specific year by analyzing the given data. By testing and modifying the spatiotemporal model, we can come to a rational conclusion that our model can forecast the actual situation in certain extent.

Joint relay-user selection in energy harvesting relay network with direct link

In this paper, a joint relay-user selection (JRUS) scheme is proposed for an amplify-and-forward full-duplex (FD) relay network which includes one source node, multi-relay node and multi-user node, and the direct link between the source node and the user node is considered to convey information. Each FD relay node is energy-constrained and the simultaneous wireless information and power transfer technology is employed to harvest energy. A power splitter at each FD relay node splits the received signals into two components for energy harvesting and information processing. The implementation of the proposed JRUS scheme includes two steps: (1) the optimal user node is selected according to signal-to-noise ratio of the direct link between the source node and the user nodes; (2) the optimal energy harvesting relay node with optimal power splitting (PS) factor is picked out based on signal-to-interference-plus-noise ratio of the relaying link. The outage probability of the investigated relay network with the JRUS scheme is derived. In order to characterize the diversity order, we further present the asymptotic outage probability at high SNR. Moreover, the optimal PS factor of each relay node is calculated by minimizing the outage probability of the reconstructed relay network. Finally, numerical results demonstrate the accuracy of our performance analysis and the efficiency of the proposed scheme.

Paradoxos vivenciados pelo uso das tecnologias móveis no processo individual de tomada de decisão

O crescimento do uso das Tecnologias da Informação Móveis e Sem Fio (TIMS) nas organizações tem viabilizado cada vez mais o trabalho móvel, trazendo tanto benefícios quanto desafios aos processos de trabalho. O objetivo desta pesquisa foi compreender quais são os paradoxos vivenciados com o uso de TIMS na tomada de decisão individual em contexto de mobilidade. Foi realizada uma pesquisa qualitativa por meio de um grupo focal e entrevistas semiestruturadas, com um total de 26 participantes (executivos e gestores de nível intermediário) que tomam decisões nesse contexto. Os resultados corroboram paradoxos já identificados na literatura, e que se manifestam nos processos de tomada de decisão em contexto de mobilidade: Ocupado e Disponível, Planejamento e Improvisação, Engajamento e Desengajamento, Competência e Incompetência. Além disso, novos paradoxos foram identificados: Pessoal e Profissional, Maior Colaboração e Menos Face a Face, Decisões mais Ágeis e Decisões com Maior Exposição ao Erro.

Outage performance of cognitive DF relaying networks employing SWIPT

In this paper, the outage performance of a cognitive relaying network over Nakagami-m fading channels, employing simultaneous wireless information and power transfer (SWIPT) technology is analyzed and evaluated. The operation of this network is considered in conjunction with the conventional decode-and-forward (DF) and incremental DF (IDF) protocols. For the conventional DF protocol, it is assumed that there is no direct link between the secondary transmitter (S) and the secondary destination (D), while (for both protocols) after harvesting energy, the relay node (R) always helps to forward the resulting signal to D. However, for the IDF protocol, R assists in relaying S’s information to D only when the direct communication between S and D has failed. Furthermore, for both DF and IDF protocols, we assume there is no power supply for R, and R harvests energy from the transmitted signal of S. We derive exact analytical expressions for the outage probability at D in DF and IDF protocols, respectively, in terms of the bivariate Meijer’s G-function. Performance evaluation results obtained by means of Monte-Carlo simulations are also provided and have validated the correctness of the proposed analysis.

Transmission Strategy Design and Resource Allocation in D2D Multicast Cooperative Communications with SWIPT

This paper proposes a new transmission strategy for device‐to‐device (D2D) multicast cooperative communication systems based on Simultaneous Wireless Information and Power Transfer (SWIPT) technology. The transmission block is divided into two slots. In the first slot, the source user transmits the information and energy to the help user by SWIPT. In the second slot, the help user uses the cellular spectrum and forwards the information to multiple receivers by using harvested energy. In this paper, we aim to maximize the total system rate, and to tackle the problem, we propose a two‐step scheme: In the first step, the resource allocation problem is solved by linear programming. In the second step, the power‐splitting coefficient value is obtained by taking the benefit of help user into account. Numerical results show that the proposed strategy not only effectively improves the overall throughput and spectrum efficiency but also motivates the cooperation.

Secrecy Analysis of SWIPT-Enabled Cooperative Networks With DF HPTSR Protocol

The simultaneous wireless information and power transfer (SWIPT) technology is recently used to sustain the lifetime of energy-constrained relay nodes in wireless cooperative networks. An example to achieve this technology is the hybridized power-time splitting-based relaying (HPTSR) protocol. However, the information security aspect of wireless cooperative networks is important and needs adequate attention. In this paper, we perform the secrecy analysis of a SWIPT-enabled cooperative network with source–relay link-based decode-and-forward HPTSR protocol, which can enhance the operational lifetime of the relay nodes and the secrecy performance of the entire cooperative network. Specifically, we examine the secrecy performance of the considered network by deriving the analytical expressions for the near-optimal power splitting factor, secrecy outage probability, and secure energy efficiency of the system. All analytical results are confirmed by numerical simulations. Our results show that the SWIPT-enabled cooperative network outperforms the conventional relaying scheme-based network presented in literature at relatively high signal-to-noise ratios.

Artificial Light at Night and Obesity: Does the Spread of Wireless Information and Communication Technology Play a Role?

Purpose: Artificial light at night (ALAN) may influence body mass via different mechanisms, including the suppression of the melatonin production by direct ALAN exposure, and by causing a shift in the food intake, due to activities enabled by ALAN. In the present paper, we attempt to separate these potential mechanisms by introducing measures of Internet and cellular phones use that reflect the proliferation of information and communication technologies (ICT) in individual countries of the world.
 Methods: In addition to ICT measures, our multivariate regression models link country-specific obesity rates with ambient ALAN levels, captured by satellite sensors, with per capita GDP, urbanization, birth rate, food consumption and regional differences.
 Results: As the analysis reveals, in low-income countries, the number of cellular phone subscriptions emerged as a statistically significant predictor of obesity rates (t>2.386; P<0.05), while in the rest of the world countries, obesity was found positively related to ALAN (t>2.251; P<0.05), but not to Internet and cellular phone use (P>0.1).
 Conclusion: We explain these differences by the fact that Internet and cellular phones are widely spread in low resource countries, and their use may become an effective circadian disruptor, despite relatively low ambient ALAN levels, attributed to limited economic resources available.

The research and analysis of wireless digital information technology for postoperative analgesia management

Objective To compare the clinical efficacy, adverse reactions, and management effect of postoperative intravenous analgesia for patients with postoperative intravenous analgesia with digital information technology and electronic analgesia pump system. Methods Totally 100 patients with postoperative intravenous analgesia (PCIA) were selected from April 2015 to September 2015 with postoperative intravenous analgesia and randomly divided into Wireless analgesic pump system Group (A group) and electronic analgesia pump group (group B), n=50 each group. Pain score (NRS) , sedation score (OAA/S), comfort score (BCS) , the total number of times and the number of effective press were pressed in patients were observed and compared between two groups after postoperative analgesia 1 hour (T0), 4 hour (T1), 10 hour (T2), 16 hour (T3), and 24 hour (T4). Patients with early adverse reactions, patients and ward medical staff satisfaction, pain pump failure found in the medical staff and effective treatment of adverse events were also observed and compared in two groups. Results There were no significant difference of patients with NRS, OAA/S and BCS in two groups(P>0.05). Adverse reactions after postoperative analgesia, total number of times and the number of effective press had also no significant difference in two groups(P>0.05). Two groups of patients with air blockage, incomplete analgesia rate of adverse events was not significantly different (P>0.05). Medical workers in time [(1.0±0.5)min vs (3.0±2.1)min, P<0.05], effective processing time [(4.0±2.1)min vs (8.0±5.1) min, P<0.05] in group A was significantly shorter than group B. The patient satisfaction in group A was significantly higher than group B(12.0±4.2 vs 9.0±3.1, P<0.05). The satisfaction degree of medical staff in group A was also significantly higher than group B(13.0±3.1 vs 10.0±2.1, P<0.05). Conclusions The digital information technology of wireless analgesic pump is applied to postoperative analgesia for medical workers to standardize management, improve the work efficiency, and increase the satisfaction of patients and medical staffs. Key words: Computer communication networks; Analgesia; Pain, postoperative/TH