Статьи журнала - International Journal of Wireless and Microwave Technologies
Все статьи: 532
A Hybrid Selection Approach Based on Advanced Antenna Technologies for Cellular LTE-A
Статья научная
While addressing cellular network performance issues, resolving problems with coverage and capacity is critical. The coexistence of cellular networks and smaller femtocells working within the macrocell area is among the alternative solutions. The simultaneous functioning of macrocells and femtocells, however, introduces new technical challenges that pose serious concerns about the efficiency of cellular networks. Therefore, this work proposes a hybrid approach based on variant advanced antenna technologies including MIMO methods and antenna systems for the deployment of femtocells and macrocells. To accomplish this, three distinct LTE-A network models with and without femtocells are set up with different architectures for high-density areas. The models further cover tri-sector and omnidirectional antenna systems to analyze the relevant effects on the performance of the LTE-A macrocells as well as femtocells. Also, to extend the analysis, integration of different MIMO methods for the models is provided. The networks are implemented and the link performance evaluation is carried out with regard to spectral and energy efficiency, cell and user throughputs, fairness, and SINR. The results contribute to determining the performance gains and energy saving of the LTE-A femtocells as well as macrocells by employing different advanced antenna technologies.
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A Linear Polarized Coaxial Feeding Dual Band Circular Microstrip Patch Antenna for WLAN Applications
Статья научная
A dual band linear polarized micro-strip antenna is designed and simulated to obtain electronic circuit miniaturization of an antenna in high speed wireless local area networks (IEEE 802.11a standard). The proposed antenna contains a substrate layer (FR-4 lossy) with a dielectric constant of 4.4 and there is a circular patch on the upper layer of the substrate. The coaxial probe feed is used to excite the desired antenna which reduces the spurious radiation and hence obtained good efficiency. It is shown that using cavity model 20% excess bandwidth can be achieved while maintaining the lower size of the antenna. An 'E' shaped slot is introduced in the radiating patch to obtain dual band resonance frequency with maximum current distribution on the surface. Finally the simulated results using Computer Simulation Technology (CST) microwave studio 2009 in this design is compared with manual computation results which are found to be suitable for WLAN applications.
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A Low-Cost Noise Wave Correlator for Noise Parameters Extraction by Cold Noise Power Measurement
Статья научная
Conventionally, the noise parameters of a Device under Test (DUT) which generally characterize the noise performance of the DUT, are obtained via the impedance tuner technique. The authors have previously presented a technique which eliminates the need for impedance tuner, and rather employs an 8-port network that enables the extraction of the noise correlation matrix of a given DUT and thus its noise parameters. In this paper, we present a further simplification of the 8-port network technique, which also eliminates the need for a conventional external noise source. Cold noise powers emanating from a DUT are measured via a 6-port network with the aid of matched termination. The measured noise powers provide sufficient information for determining the noise wave correlation matrix of a DUT, which are then converted into the conventional 2-port noise parameters. The proposed technique is simple, fast and is verified to give a good estimation of the noise parameters of selected DUTs.
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A Method of Target Detection in Remote Sensing Image Captured based for Sensor Network
Статья научная
A refined energy constrained minimization method is developed for target detection in hyperspectral remote sensing images captured by unmanned aerial vehicles (UAVs) during their surveillance missions, which has been tested in the experiment under this paper. The experiment result proves, in the detection process, this method can effectively restrain noises so far as the spectral characteristics of any potential target are known, and find sub-pixel targets out effectively from the hyperspectral remote sensing image in unknown background spectrum.
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A Metric for Evaluating Security Models based on Implementation of Public Key Infrastructure
Статья научная
International security evaluation metrics are too general and not focused on evaluating security models implemented using Public Key Infrastructure (PKI). This study was conducted to develop the metric for evaluating security models based on implementation of PKI by using insights from literature. Literature review was done based on inclusion and exclusion criteria. The developed metric was tested using ranking attributes and ranking scales. The results reveal that the developed metric is applicable for evaluating security models based on implementation of PKI. This is verified by the tabular results indicating evaluation of selected security models based on implementation of PKI by using ranking attributes and ranking scales. This study contributes to the body of knowledge a metric for evaluating security models based on implementation of PKI.
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A Multi-objective Fuzzy Logic based Multi-path Routing Algorithm for WSNs
Статья научная
Wireless Sensor Networks (WSNs) have included one of the major challenges as energy efficiency. The optimal routing is the better solution for tackling the energy-efficiency problem as the energy is consumed with massive amount by the communication of a network. The clustering technique is the reliable data gathering algorithm for achieving energy-efficiency. The data transmit to the cluster head (CH) by each node that belonging to the cluster for clustered networks. The data transmission towards the BS or SINK is occurred once all data is received by CH from all member nodes. In multi-hop environments, the data transmission happens via other cluster-heads. It leads to the earlier death of CHs that are nearer to the SINK because of the heavy inter-cluster relay, i.e. called as hot-spot problem. The existing methods of unequal clustering approaches have been used to resolve this issue. The algorithms generate the clusters with smaller sizes while approaching towards the sink for reducing the intra-cluster relay. These algorithms didn’t consider the hotspot problem very effectively. Therefore, in this work, we introduce a multi-objective fuzzy logic based multi-path routing solution (MOFL-MPR) to address the above said problem. The popular clustering algorithms have been evaluated the performance results and the MOFL-MPR is outperformed the existing algorithms based on the obtained experimental results in terms of stable CH selection, energy efficiency and better data delivery.
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A Multi-step Attack Recognition and Prediction Method Via Mining Attacks Conversion Frequencies
Статья научная
Massive security alerts produced by safety equipments make it necessary to recognize and predict multi-step attacks. In this paper, a novel method of recognizing and predicting multi-step attacks is proposed. It calculates attack conversion frequencies, and then mines the multi-step attack sequences. On this basis, it matches the new alert sequences dynamically, recognizes the multi-step attacks and predicts the next attack step. The result of experiment shows that the proposed method is effective and accurate.
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A Multicast Routing Mechanism in Mobile Ad Hoc Network Through Label Switching
Статья научная
Merging MPLS into multicast routing protocol in Mobile Ad hoc network is an elegant method to enhance the network performance and an efficient solution for multicast scalability and control overhead problems. Based on the Wireless MPLS technology, the mechanism and evaluation of a new multicast protocol, the Label Switching Multicast Routing Protocol (LSMRP) is presented in this paper.
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A New Framework of Honeypots Network Security Using Linear Regression Decision Algorithm
Статья научная
The expansion of the Internet and shared networks aids to the growth of records generated by nodes connected to the Internet. With the development of network attack technology, all Internet hosts have become targets of attack. When dealing with new attacks (such as smart ongoing threats) in a complex network environment, existing security strategies are powerless. Compared to existing security detection techniques, honeypot systems (IoT research) can analyze network packets or log files being attacked, and automatically monitor potential attack. Researchers can use this data to accurately capture the tactics, strategies, and techniques of threat actors to create defense strategies. However, for general security researchers, the immediate topic is how to improve the honeypot mechanism that attackers do not recognize and quietly capture their actions. Honeypot technology can be used not only as a passive information system, but also to combat zero-day and future attacks. In response to the rapid development of honeypot recognition with machine-learning technology, this paper proposes a new model of machine learning based on a linear regression algorithm with application and network layer characteristics. As a result of the experiment, we found that the proposed model was 97% more accurate than other machine learning algorithms.
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A New Half-blind Algorithm of Smart Antenna for Mobile Terminal
Статья научная
The core of smart antenna is its adaptive algorithm. For the characteristics of TD-SCDMA mobile terminal, we analyze the advantages and disadvantages of various algorithms and propose a semi-blind algorithm combining the NLMS algorithm and the CMA algorithm in this paper. The new semi-blind algorithm has strong robustness and low complexity. It is suitable for smart antenna of TD-SCDMA mobile terminals.
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A New Joint Antenna Selection Algorithm Based on Capacity
Статья научная
Antenna Selection in MIMO systems can increase the system capacity, reduce the MIMO system complexity and cost of radio links effectively. In this paper, a new joint antenna selection algorithm was presented which can adaptively change the number of the selected transmitting and receiving antenna number according to the channel station. It can obtain the similar system capacity with the optimal joint antenna selection algorithm in any correlation coefficient, but the calculated amount is far less than the optimal joint algorithm.
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A New MATLAB based Microstrip Filter Design Tool
Статья научная
This paper presents a new MATLAB-based microstrip filter design tool. Stepped-impedance resonator lowpass filter, parallel-coupled bandpass filter, and end-coupled bandpass filter are included. Circuit-theory based closed-form mathematical expressions are used, instead of rigorous electromagnetic analyses. This results in significant reduction in analytical effort, without substantially affecting the accuracy. The results are verified against results obtained using commercially available Ansoft simulation tool. The agreement between the two sets of results is good enough for all practical purposes.
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A New R*Q-tree Spatial Index based on the Delaying Selection and Clustering Splitting
Статья научная
The original R*Q-tree is an important class of query index in the spatial database, but when carry on frequent insertion and deletion, the efficiency is very low, because its construction cost is much more than that of the other query methods. So the new R*Q-tree using the delaying and Clustering splitting technology has been proposed for improving the shortcomings of the original R*Q-tree. When the data objects are inserted into the new R*Q-tree, the nodes may overflow. During the process of insertion, rather than split the node immediately, it attempts to insert the nodes into the adjacent neighboring nodes by using of the delaying selection splitting technology until they are full. If the adjacent neighboring nodes are full, it will use the clustering technology to split the nodes, data items will be reorganized between the neighboring nodes and the splitted nodes. The new R*Q-tree can ensure the premise of the query performance and the cost of structure greatly reduced, at the same time, significantly the space utilization of the index structure is improved. Finally, the experimental analysis and appraisals show that the operation efficiency of the new R*Q-tree is enhanced. And in the new R*Q-tree and the promoter region, there are no duplicated elements, so the structure of the new R*Q-tree can be simplified.
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A New Ranging Technique for IEEE 802.16e Uplink
Статья научная
Aiming at the shortcomings of the traditional ranging algorithm, this paper proposes a new ranging technique for 802.16e uplink in the frequency domain. The ranging technique eliminates the effect of the timing offset by computing the frequency difference of adjacent sub-carriers in the ranging channel, which reduces the search space from two dimensions to one dimension. When there is slot, the ranging code can be detected by adopting a threshold. The ranging technique is implemented through one-dimension search in the frequency domain, and consequently the complexity can be reduced and without losing the performance of timing estimation. The simulation results show the good ranging performance of this technique.
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A New Secure Strategy for Small-Scale IEEE 802.11 Wireless Local Area Network
Статья научная
As the main secret-key encryption techniques of the wireless local area network (WLAN) have been proven to be unsafe, wireless network security is faced with serious challenges. It is unpractical for home users and small companies to buy expansive network equipments to improve the network security. Therefore, the secure strategy of wireless network needs to be changed. In this paper, we first introduce secure issues of the main secret-key encryption techniques currently adopted by the most popular commercial wireless routers. Then we propose a new strategy for small-scale IEEE 802.11 wireless local area network which can strengthen the network security. The new secure strategy is based on web authentication with unshared key and virtual local area network (VLAN) in wireless network. It can provide protection against practical attacks which are popular nowadays. Moreover, it is simple, wieldy and low-cost.
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A New Solution of Multicast Packets Management for Managed Ethernet Switch
Статья научная
This paper has a discussion on the new solution of IGMP management for multicast message in industrial Ethernet. It proposed a new mechanism to minimize the congestion which is based on the taking an adaptive decision during transferring multicast messages. Proposed approach is that a device requesting to start and stop the reception of the multicast streams is accomplished through IGMP join and Leave message requests. Quality of Service (QOS) as a component is supported by the Switch Manager as well as features built into the micro chip. The IGMP Snooping component monitors (snoops) these join and leave messages to allow it to know which streams to prune from which ports. it is a service provided by most managed Ethernet switches. However, the ICIE (Intelligent Controller for Industrial Ethernet) does not provide this capability and requires that another device in the network supports the querier functionality. It is through the external devices solicitation of join messages that allow the IGMP Snooping component to correctly decipher on which ports the downstream listeners are connected.
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A New Technique for Detection and Prevention of Passive Attacks in Web Usage Mining
Статья научная
Data theft and data attack is very common with internet users and web log files. Web log file is the proof of authentication of any user over any website. Many unauthorized users change them according to their requirement. Attacks like sql injection, brute force attack, IP spoofing might cause severe damage to the database system In this encryption techniques and optimization technique have been applied in order to check the unexpected arrival of messages or queries and the system parameter.
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A New Three-party Key Exchange Protocol Based on Diffie-Hellman
Статья научная
The goal of key exchange protocol is to establish a common and secure session key using the interactive communications. The existing schemes are usually in the pattern of ‘user-server-user’, so are weak in reality. In this paper, a new three-party key exchange protocol based on Diffie-Hellman was proposed which contains the following characteristics: without server; providing key secrecy and forward secrecy; ensuring no key control; ensuring known-key secrecy.
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A Node Localization Algorithm based on Woa-Bp Optimization
Статья научная
With the rapid development of 5G technology, the era of interconnection of all things has arrived. At the same time, a variety of hardware and software are getting more and more location information through sensors, and the accuracy of location information is increasingly important. Because traditional positioning relies on satellite signals, it achieves good results outdoors without obstruction, but indoors, due to the obstruction of various walls, such as Beidou satellite navigation system and U.S. Global Positioning System, it is difficult to meet the accuracy requirements for indoor positioning. Therefore, how to improve the positioning accuracy of indoor nodes has become a research hotspot in the field of wireless sensor. In order to improve the indoor positioning accuracy, this paper combines artificial neural network, intelligent optimization algorithm and node positioning to improve the accuracy of indoor positioning. One of the essences of the neural network is to solve the regression problem. Through the analysis of indoor node positioning, it can be concluded that the accuracy of distance-based positioning method lies in finding the relationship between signal strength and distance value. Therefore, the neural network can be used to regression analysis of signal strength and distance value and generate related models. In order to further improve the accuracy and stability of indoor node positioning, a method combining whale optimization algorithm with neural network is proposed. By using the whale optimization algorithm to find the optimal parameters of the neural network model, the training accuracy and speed of the neural network are improved. Then, using the excellent fitting ability of the neural network, the mapping relationship between RSSI value and distance value of indoor nodes is fitted, and the corresponding regression analysis model is generated, which can minimize the noise problem caused by abnormal signal attenuation and reduce the indoor positioning error. Finally, the data is processed by the neural network to get the parameters needed in the positioning algorithm. The experimental results show that the node positioning model based on the optimized neural network and the single optimization algorithm has significantly improved the positioning accuracy and stability.
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Статья научная
Researchers have developed an innovative approach to ensure seamless connectivity in ubiquitous networks with limited or irregular network coverage. The proposed method leverages advanced network technologies and protocols to seamlessly establish and maintain network connections across various environments. It integrates multiple wireless communication technologies and dynamic network selection algorithms, overcoming issues like poor reliability, limited scalability, and security problems. Compared to existing solutions, the method exhibits improved connection handover efficiency, network throughput, and end-to-end delay. Considering user mobility, network availability, and quality of service needs, it makes informed decisions about the most suitable network connections. The proposed method is expected to significantly impact the development of future ubiquitous networking solutions.
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