Статьи журнала - International Journal of Wireless and Microwave Technologies
Все статьи: 544
Статья научная
The 802.11 ac protocol is widely utilized in local-area-networks with wireless access (WLANs) because of its effective 5GHz networking technology. Several path-loss and link-speed (LS) prediction models have previously been employed to aid in the effective design of 802.11 WLAN systems that predict the received-signal-strength (RSS), and LS between the client and the access-point (AP). However, majority of them fail to account for numerous indoor propagation phenomena that affect signal propagation in complex environments. This includes the shadowing that influences RSS, especially in a network system with multiple moving parts and small-scale fading, where signal reflections, obstacles, and dispersion lead to RSS fluctuations. Therefore, taking into account shadow fading influence in the LS estimation model is critical for enhancing estimation accuracy. Previously, we proposed modification of the simple log-distance model by taking shadowing variables into account which dynamically optimize the RSS and LS estimation precision of the previous model. Though our modified model outperforms the prior model, the model’s accuracy has not been evaluated in comparison to a wide range of other mathematical models. In this paper, we present the performance investigation of various estimation models for RSS and LS estimations of 802.11ac WLANs under various scenarios and analysis their performance accuracy by considering several statistical error models. To test its relative effectiveness the proposed modified model's performance is also compared against two existing machine learning (ML) approaches. To calculate the models parameters including shadowing factor, we first show the experimental results of RSS and LS of the 802.11ac MU-MIMO link. Then, we tune the path-loss exponent, shadowing factors, and other parameters of models by taking into account experimental data. Our estimation results indicate that our modified model is more precise than the other mathematical estimation models and its accuracy is very similar to the random forest (RF) ML model, in an extensive variety of consequences with less error.
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Performance analysis of NLM interleaving scheme for CPM OFDM system
Статья научная
A New Logistic Map interleaving is the most common method for continuous phase modulation based orthogonal frequency division multiplexing (CPM-OFDM) system over a fading channel. The selection of a "good" interleaver having to express in order that the interleavers are weakly correlated. Interleaver doesn’t involve massive memory to reserve it and a massive bandwidth to communicate in the midst of the transmitter and the receiver, and need to be simple to produce. An efficient chaotic maps randomization (CMR) generates scrambled uncorrelated randomized data can greatly improved the performance of CPM-OFDM system and improved symbol error rate (SER) could be attained. In this study, advise a new one-dimensional chaotic map, the "New Logistic Map (NLM)". Encryption is carried out with logistic map even as a chaotic logistic map interleaving process is used to boost the immunity to noise and fading in communication channel. Furthermore, a evaluation between NLM interleaving and random interleaving is performed in terms of bit error rate(BER).Simulation results shows that the data transmission over wireless channel using propose NLM interleaving is more immune to fading and noise and get better the performance of CPM-OFDM system.
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Performance optimization of ad hoc on demand vector routing protocol in cognitive radio network
Статья научная
Mobile Ad Hoc Network has given importance in last few years by researchers. Implementations of Ad Hoc network in cognitive radio environment are emerging kind of wireless network [1, 5]. The communication is done by the secondary user in the free frequency band available in the spectrum of the primary user. In this paper, we have projected proficient routing solution by the maintenance of the link for AOMDV protocol for cognitive radio ad hoc Network. We have used ns2 Simulator for simulations. The link maintenance makes the system more efficient that is evaluated by simulation and comparing it with a classical routing protocol.
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Polynomial Algorithm for Node Deployment in Hybrid Wireless Sensor Networks
Статья научная
When detecting a target or monitoring a physical phenomenon in a region, the deployment problem is fundamental in these applications. Traditionally, stationary sensor networks are deployed to carry out the sensing operations. It is well known that the mobility of sensor nodes can improve the coverage and the probability of the detecting, so we deal with the problem of detecting a target using hybrid sensor networks which contain both stationary sensors and mobile sensors. In this paper, to begin with, we prove that the node deployment problem is NP-complete. Then, one polynomial algorithm for node deployment in hybrid wireless sensor networks is proposed, which aims at minimizing the number of all sensors to reduce the cost. The simulations verify the efficiency of our algorithm.
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Positioning Algorithm for Wireless Sensor Network Based on Adaptive Genetic Algorithm
Статья научная
It is very important for wireless sensor network to position the nodes’ location because location information is favorable for providing network service such as geographic routing, people tracking and so on. After researching the range-based atomic multilateration algorithm carefully, this paper presents a novel positioning algorithm based on adaptive genetic algorithm (AGA). The new positioning algorithm uses adaptive genetic algorithm to search the optimal solution of nonlinear multivariate positioning equations set. Furthermore, the proposed algorithm uses a new model to estimate range error in order to improve the localization accuracy. Simulation results show that the proposed scheme has better robust performance. Compare with general genetic algorithm, adaptive genetic algorithm has better localization accuracy and higher speed of convergence.
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Power Allocation for Balancing Spectrum Efficiency and Power Consumption in Cognitive Relay Networks
Статья научная
In order to guarantee the QoS requirement of secondary users and not to affect the outage probability of primary user in cognitive relay networks, we propose two optimal power allocation models: (1) maximizing the transmission rate of secondary users; (2) minimizing the total power consumption. Theory analysis shows that two optimal power allocation models conflict between spectrum efficiency and power consumption. Furthermore, an optimal power allocation model which joints the transmission rate and the total power consumption in cognitive relay networks is proposed. By using the Lagrangian method, the optimization algorithm for this model is designed. The proposed algorithm can achieve the trade-off between the transmission rate and the total power consumption by varying the weight. Simulation results show that the proposed algorithm can effectively adjust the transmission rate and the total power consumption of secondary users.
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Power Factor Analysis of the Linear Motor in Mines
Статья научная
This paper introduces the structure of linear motor in mines. Analyze the power relation of power-AC -linear motor – vibrant machine, based on this, count the power factor; and make mechanical analysis to the vibrancy, get the power factor, which should be: in the precondition of without collision for the top and bottom magnet, do best to decrease the δ_0 to close to ΔΧ_m (ΔΧ_m depends on the technique of the vibrant load), make Κ_δ close to 1 and λ_e close to critical maximum λ_(em) . It is significantly useful to design linear motor.
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Статья научная
Prediction of location has gained lot of attention in different applications areas like predicting the path or any deviation like taxi-route, bus route, human trajectory, robot navigation. Prediction of the next location or any path deviation in RFID enabled supply chain path followed in the process is quite a novel area for the related techniques. The paper defines the architecture for the outlier detection in RFID enabled Supply Chain Path based on historical datasets .Given the training datasets, different classification models are compared for the accurate prediction of the outlierness of the path followed by the tagged objects read by RFID readers during the supply chain process. Comparison of Hidden Markov Model(HMM), XGBoost(decision tree based boosting),Recurrent Neural Network(RNN) and state of art technique in RNN known as Long Short Term Memory (LSTM) is done .To our knowledge LSTM has never been used for this application area for outlier prediction. For the longer path sequences, LSTM has outperformed over other techniques. The training datasets used here are in the form of the record of the outlier positions in particular path and at particular time and location.
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Preserving privacy in cloud identity management systems using DCM (Dual Certificate Management)
Статья научная
In these days all businesses trying to use global applications on cloud computing infrastructure to reduce their costs and also decentralize their application. This movement also causes more security risks over the unbounded cloud environment. Therefore, accessing enterprise information for an unwanted user will be more than other environments. Thus, the proposed Identity Management System (IDMS) tries to preserve security in communication between clients and server over cloud computing. The proposed method suggested token based Identity Management and also enhanced privacy by adding one. Dual Certificate Manager (DCM) block is a replacement for a combination of symmetric and asymmetric cryptography, which is commonly used for SSL/TLS protocol to immune data transmission, uses asymmetric cryptography in both participants. Furthermore, for more privacy and invulnerability DCM uses Elliptic Curve Cryptography (ECC) as asymmetric cryptography algorithm.
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Prevention of session hijacking attack in VANETs using intrusion detection system
Статья научная
Vehicular Adhoc Networks (VANET) is a type of road network that provides road safety and other infotainment applications to drivers and passengers for an effective and uninterrupted communication. In this network, the communication between the vehicles are equipped with the Road Side Units (RSU). VANET is the major component of Intelligent Transportation System (ITS). Research on Vehicular Adhoc network security presents many challenging issues to the researchers. The security mechanism available for VANETs are not highly effective. Hence it is as on time requirement of new and sophisticated security solutions. This paper mainly focuses on Intrusion Detection System (IDS) for VANETs to prevent Session Hijacking Attack (SHA). The work discusses on the total number of packet generated, sent, received and dropped with varying number of nodes with the help of Network Simulator-2 (NS2) and the inferred results are discussed.
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Статья научная
Pertaining to the rapid usage of cloud computing, cloud based approaches are growing as an fascinating domain for numerous malignant tasks. Security is one of the vital issues faced by the cloud computing environment while sharing resources over the internet. Consumers are facing distinct security hazards while using cloud computing platform. Previous works mainly attempted to mitigate the side channels attacks by altering the infrastructure and the internal procedures of the cloud stack. However, the deployments of these alterations are not so easy and could not resist the attacks. In this paper, the authors attempted to solve the issues by enhancing the VM Placement policies in such a way that, it is complex for the invaders to collocate their object. A secure Dynamic VM placement approach is presented for the VM allocations into different servers in the cloud. The performance comparison of the suggested methodology is shows that the proposed approach has better efficiency evaluations such as hit rate, loss rate and resource loss when compared to other V M placement policies.
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Privacy Enhancing for Fog Computing based - IoT
Статья научная
With the massive inflation of newly developed technologies, recourse to data has become a necessity in light of the current inflation and excessive need dominating the world and developed societies. According to the control of millions of smart devices and sensors connected to an interconnected and controlled automated system within installed scales due to the services provided by IOT devices through the created fog layer that connects the cloud centers and those devices, in addition, very large amounts of that data including public and private are passed through the connection of Internet of Things devices to each other. Smart and advanced networks as one of the fog computing applications play a prominent and accurate role in the infrastructure for reliable and sound data transmission. Accordingly, the process of data aggregation is an important and common matter in the world of fog-enhancing Internet of Things, so preserving the privacy of that data is a matter of concern, and based on this principle, we propose in this paper a model for data aggregation that maintains privacy using a foggy computing environment called PPFDA (privacy preserving based- fog computing data aggregation). We use in our scheme DF homomorphic cryptosystem as it consider one of the aggregation models that ensures the privacy purpose. The theoretical results and analyzes show that our design is ensuring the privacy of data during collection using an algorithm of DF. The results confirm that the proposed scheme achieves security and privacy purposes in modern network systems for the Internet of things based in fog computing. In addition, it contributes significantly to the efficient performance of storage operations.
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Privacy Preserving Similarity Measurement
Статья научная
Data similarity measurement is an important direction for data mining research. This paper is concentrated on the issue of protecting the underlying attribute values when sharing data for the similarity of objects measurement and proposes a simple data transformation method: Isometric-Based Transformation (IBT). IBT selects the attribute pairs and then distorts them with Isometric Transformation. In the process of transformation, the goal is to find the proper angle ranges to satisfy the least privacy preserving requirement and then randomly choose one angle in this interval. The experiment demonstrates that the method can distort attribute values, preserve privacy information and guarantee valid similarity measurement.
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Probabilistic Constellation Extension Scheme for PAPR Reduction in OFDM Signals
Статья научная
In this paper, a combinational method is proposed to mitigate the peak-to-average power ratio problem in orthogonal frequency division multiplexing signals. The proposed algorithm is an intelligent combination of the constellation extension and probabilistic techniques. It is shown that proposed technique achieves the significant reduction in peak-to-average power on maintaining sufficient bit error rate with a slight increase in computational complexity compared to conventional schemes.
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Статья научная
Beibuwan Economical Zone of Guangxi Province has the necessary basis and conditions to develop the madicine manufacturing industry.It is significant to select products which ficilitate the development of madicine manufacturing industry from the prospective of promoting the development of the industry smoothly. The feature of selection of essential products of medicine manufacturing can be summarized as multi-objectiveness, multi-layer, fuzziness and the interaction and penetration of different objectives. Due to these characteristics, analysis is made through analytic hierarchy process (AHP) by this thesis. The paper put forward the developmental sequence of madicine manufacturing industry in Beibuwan Economical Zone of Guangxi Province by adopting analytic hierarchy process, and pointed out that, among others, the technical competence is the most influnctial factor of a company. The appropriate developmental sequence of the products selected is biological and biochemical products, medicinal chemicals, chemical medicine and preparations. This research is in favor of speeding up the development of competitive products and creating industry competition.
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Programming SDNs: A Compass for SDN Programmer
Статья научная
The modern communication networks have evolved from simple-static systems to highly flexible and adaptive systems facilitating dynamic programmability and reconfiguration. This network evolution has influenced the lowest level of packet processing in data plane to highest level of network control and management functions. It has also influenced the overall network design and architecture which is clearly evident from the emergence of SDN and NFV. With the wide-spread acceptance of SDN, a novel networking paradigm, the network programmability has re-appeared as a top research area in networking and numerous programming languages have been proposed. In this paper, we present a systematic review of various state-of-the-art SDN programming languages used to program different network planes. We follow a top-down approach, starting with the high-level or top-tier programming languages followed by the data plane or bottom-tier programming languages. We have provided an in-depth analysis of various top-tier and bottom-tier programming languages and compared them in terms of most prominent features and supported abstractions. In addition to it, we have elaborated various programming models used in different bottom-tier programming languages which provide necessary abstractions for mapping diverse functionalities of data plane algorithms splendidly onto the specialized hardware like ASICs. Lastly, we have highlighted the research challenges in SDN programming languages like cross platform programming, necessary language libraries, support for network verification, NFV, stateful and inline packet processing, which need to be incorporated into existing programming languages to support diverse functions required in next generation networks.
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Статья научная
One of the important studies in 6G aerial radio access networks is the propagation channel modeling. The high accurate propagation channel model will save cost and time, and is more effective in the design of the air radio access network system. However, existing channel models are limited to 1 THz, while 6G wireless technology is expected to operate up to 3 THz. In this paper, the propagation channel from 275 GHz to 3 THz is modeled by modifying the Friis equation, and each parameter in the model is described and analyzed analytically. The main factors that contribute to wireless signal attenuation at terahertz, such as atmospheric oxygen and water vapor, rainfall, and cloud factors, are also discussed in detail. Furthermore, the propagation channel calculation App for 6G low-altitude platform access networks application has been built using MATLAB GUI.
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Propagation Profile and Signal Strength Variation of VHF Signal in Ekiti State Nigeria
Статья научная
This paper presents the experimental results of a study on radio frequency attenuation path loss conducted in Ekiti State, Nigeria. The objective of the study is to develop a path loss model comparable to the existing path loss models through a real time application of outdoor VHF signal propagation measurements of the Nigeria Television Authority (NTA) Channel 5 and carrier frequency of 175.25 MHz located in Ado-Ekiti, Ekiti State, Nigeria. Experimental measurements were taken in three routes covering the entire state. Analysis of the data collected from the experiments resulted in models which are in agreement with the existing standard models. Root Mean Square Errors were calculated for all the path loss models. Results show that the signal of the station was generally poor along the routes considered as the deviations of the measured path losses from the free space path loss exceed 6 dB in most cases.
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Proposed WiMAX hybrid scheduler with split FTP traffic and its performance evaluation
Статья научная
The most promising broadband wireless access technology, Worldwide interoperability for Microwave Access (WiMAX), is the commercial name of IEEE 802.16. It is popular due to its middle range access mobile, high data rates, high scalability and convenient deployment. WiMAX provides Quality of Service (QoS) to various triple-play services (voice, video and data) through five service classes. QoS provisioning to various service classes in WiMAX is achieved by a scheduler at MAC layer. Selection of appropriate scheduler is based on certain design goals, such as attainment of QoS required for variety of applications, fairness to all services, reduced complexity etc. However, in general, File Transfer Protocol (FTP) traffic starves for bandwidth under the presence of high priority real-time traffic. This paper proposes a WiMAX hybrid scheduler that integrates homogeneous schedulers namely Weighted Fair Queuing (WFQ), strict priority and a Round Robin (RR). The unique feature of the proposed scheduler is that it has a splitter for FTP traffic with varying ratio and two stage priority schedulers for providing proper traffic load distribution for packet scheduling. The analytical modelling of proposed scheduler is achieved by Markov Chain and balance equations are solved to derive performance indicators such as mean queue length of packets, mean queuing delay, throughput and inter-class fairness for various triple-play services. The analytical results show that, as compared to recently reported hybrid WiMAX schedulers, proposed hybrid scheduler fulfils QoS requirements of various services and the splitting of FTP traffic has improved fairness among various services.
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Providing Useful Data Reliably to Mobile Cloud Users from Random Wireless Sensor Network
Статья научная
The integration of mobile cloud computing and wireless sensor network plays an important role in the field of research and industry. Data fetched from Wireless Sensor Network (WSN) are stored in the cloud and provides it to the mobile cloud users. This integration helps in providing data to users in the form of digitalization. To help the applications involving an integration of Mobile Cloud Computing (MCC)–Wireless Sensor Network, this paper finds the crucial things that influence the sensor data and WSN, and then propose a concept called Time based Priority Sleep Scheduling (TPSS). TPSS is divided into three parts 1. Based on the priority and time, wireless sensor network gateway should transmit the sensed data to cloud and 2. The algorithm used to save the battery consumption of mobile users in fetching data from the cloud is Priority Based Sleep Scheduling (PBSS); this provides data to users request based on the time slot. 3. Location Based Sleep Scheduling (LBSS) algorithm used to provide sensed data based on mobile cloud users location.
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