Статьи журнала - International Journal of Wireless and Microwave Technologies
Все статьи: 454
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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Статья научная
This Research focuses on cross layer approach to enhance the User Experience and Quality Of Service of video streaming in Long Term Evolution mobile network. During run time channel quality index is observed. Application layer requirement is fulfilled by changing modulation techniques as well as dynamic allocation of resources. This paper proposes a algorithm which improves the End-to-End Delay,Peak Signal to Noise Ratio of transmitted video over Mobile Network. Experimental results show the improvement in end to end delay by 89% and Peak Signal to Noise Ratio by 8%. Simulation in Network Simulator-3 provide credible evidence that this proposed cross-layer algorithm outperforms between earlier algorithm in providing better Quality Of Experience for real time, adaptive video streaming over Long Term Evolution.
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RF CMOS Low Noise Amplifier Design-A Case Study
Статья научная
A design methodology of Differential Design of CMOS low noise amplifier (LNA) with source degeneration for Bluetooth frequency is presented. The results show that the proposed topology is effective and can be used to achieve the minimum noise figure at all frequencies of interest. This LNA was realized in 0.18μm CMOS technology using Microwave Office Tool from AWR Inc. The measured noise figure is 2.066 dB and the gain is 20.29 dB.
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Статья научная
In the recent years the development in communication systems requires the development of low cost, minimal weight and low profile antenna that is capable of maintaining high performance over a wide spectrum of frequencies. This technological trend has focused much effort into the design of a microstrip patch antenna. The aim of this paper is to design and simulate a triangular microstrip patch array antenna using HFSS software and compare the performance of 2 elements, 4 elements and 8 elements patch arrays with that of a single patch for the same operating frequency. Also comparisons are made between the performance of series, corporate and series-corporate feed network. These arrays are designed to operate at a frequency of 11 GHz. Our goal is to obtain a high directivity with better gain and reduced losses, to be especially used for X band applications such as satellite communication, radar, medical applications, and other wireless systems.
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Real-Time Animal Location Estimation Using Wearable Sensors and Cellular Mobile Networks
Статья научная
In this article, we propose a novel concept of using an existing cellular network to find the location of animals living in outdoor environments. The proposed method has simplified hardware architecture which can be implemented at a meager cost. Moreover, the sensors communicate with existing cellular networks, which will reduce the implementation cost. The proposed system consists of a SIM 900 GSM module, a BMP280 pleasure sensor, and a battery as a wearable device that can warn the animal. The wearable device will send the real-time pressure values of the animal. In the proposed model, the pressure value, radial distance of transmitter fixed at the animal, and direction of the electromagnetic waves are used to calculate the real-time coordinates of the animals. The received pressure value and the radial distance will be used to calculate the location using this proposed model. The proposed model parameters' error was analyzed and simulated using suitable probability density distributions, and results were presented.
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Reconfigurable Origami Antennas: A Review of the Existing Technology and its Future Prospects
Статья научная
Owing to the much-gained popularity and unique properties of origami antenna, a review of some of the important types of these antennas is conducted. Origami is an ancient paper folding technique which has many applications in technical and non-technical fields. With the growing trend of utilizing origami concept, it was integrated with the electromagnetic field to realize reconfigurable antennas. This review contains some of the important applications in which the origami antennas are widely used to make the system more efficient. The development of the antennas over the years and some state-of-the-art designs are discussed along with the future trends in design and manufacturing of origami antennas. Some unique abilities of origami antennas which make them better choice than other antennas are smaller size and volume in addition to being light weight, cost efficient and easily manufacturing. They are widely used to reduce the size of bulky antennas which is very handy in many space and air borne facilities and provide reconfigurable frequency. They are even used to provide mobile range in far off regions which are not accessible with the use of ordinary antennas. The field of antenna design is vast and provides a lot of room for further advancements which are covered in future trends of the paper. This paper provides a detailed review of the different designs of antenna and points towards possible future enhancements and state of the art designs for the fabrication of antenna.
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Статья научная
Wireless sensor networks (WSN) consist of a large number of sensor nodes with finite and limited energy levels distributed throughout a finite area. The energy of the nodes is mostly consumed to send information to a central station. Extending the network lifetime through decreasing the energy consumption of the nodes has always obtained attention, due to the energy limitations in WSNs. In this paper, a multi-level genetic based clustering algorithm is proposed to extend the lifetime of these types of networks. The proposed multi-level clustering algorithm divides the geographical area into three levels according to the radio range and the clustering of the nodes in each level is performed independently. Technically, Cluster Heads (CH) consumes more energy than other nodes to transmit data. So, the proposed algorithm aims to extend the network lifetime by reducing the number of CHs. Finally, a better energy consumption balance between the nodes is realized by altering the CHs in each routing round. The results of the experiments show the superiority of the proposed algorithm in terms of and the network lifetime over other analogous protocols.
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Reduction of Feedback Based-on User Traffic Rate in OFDM Relay System
Статья научная
In order to reduce feedback while maintaining user performance in multiuser orthogonal frequency division multiplexing (OFDM) relay system, feedback mechanism based on user traffic rate is proposed. From the aspects of feedback outage probability, user weighted channel gain related to user traffic rate is compared with the system threshold. The higher user traffic rate is, the bigger the user traffic weight becomes. So the high traffic rate user has greater probability to be fed back, which can support different traffic rate. Simulation results show that the proposed feedback mechanism can bring more feedback sub-carriers to the user with high traffic rate.
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Статья научная
The work proposes Inter-Symbol Interference (ISI) reduction scheme, ISI being a major problem in Optical systems, which produces various type of non-linear distortions. So the implementation of OFDM system using Artificial Neural Network (ANN) scheme with M-QAM modulation technique is proposed and compared with the conventional OFDM system without using ANN. This proposed scheme is implementation of Back-propagation (BP) algorithm over AWGN channels to achieve an effective ISI reduction in orthogonal frequency division multiplexing (OFDM) systems. Simulation results prove that ANN equalizer can further reduce ISI effectively and provide acceptable BER and better MSE plot compared to conventional OFDM system.
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Relative Distance Based Routing for Delay Tolerant Mobile Sensor Network
Статья научная
Delay Tolerant Mobile Sensor Network (DTMSN) is the network for pervasive information gathering. Traditional static routing approaches may not fit for DTMSN due to its intermittent connectivity. This paper proposes an relative distance based routing (RDBR) strategy for DTMSN, in which nodes delivery probabilities are calculated and updated according to the latest relative distance from themselves to the sink node, and data are delivered according to nodes’ delivery probabilities. RDBR also introduces a redundant copies controlling technique based on the message priority. Simulation results show that RDBR achieves a well tradeoff between the data delivery ratio/delay and the delivery overhead.
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Remote sensing global ranged door lock security system via mobile communication
Статья научная
In this paper, a door locking system with some remarkable features is proposed which makes the locking or unlocking of a door more reliable to the user than the conventional system. Robust security access with accurate detection system is provided here. It’s a global ranged operation process that can be operated by simple mobile phone through short message service (SMS) transferring operation from any corner of the world where mobile network is available. A smooth and durable locking mechanism is provided and the inscrutable door moving control device is used for the efficient operation of controlling the door. This developed system provides a notification to the user if any person is intended to pass the door. The system also has the ability to provide information about the current condition of the door by sending simple text messages. Also, the user will be able to operate the system with more than one subscriber identity module (SIM) card. Most advantageously, this device is proposed with lowest cost estimation benefit. Finally, the performance of the designed system is analyzed by performing some real-time operation of it and found satisfactory performance.
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Research and Design of The Firewall Penetration Technology Serving to Informati on Sharing Systems
Статья научная
In the current information sharing systems, there is a problem of firewall penetration. As for this problem and based on the existing TCP and UDP penetration schemes, we analyze all kinds of possible transmission environments in practical applications, and then present a technique of UDP coordinating with TCP to penetrate firewalls. Finally, we present the realization of this method: a network switch --XIPSwitch, which is independent from various applications. The realization method can further solve the firewall penetration problem of the internal terminals in the existing information sharing systems.
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Research of NCS Real-time Performance with Judging Priority Based on Generalized Stability
Статья научная
The conceptions of generalized stability and priority judgment function of real-time node which guaranteed the generalized stability were put forward aiming at the problem of Networked Control System (NCS) real-time performance based on shared Ethernet. From the perspective of control theory and communication theory, generalized stability and priority judgment function were applied into Real-time ETHERnet (RETHER) by using real-time performance improving method of avoiding collision based on protocol in Ethernet communication protocol. Therefore, token was passed to the real-time node with highest priority and real-time data was sent, NCS real-time performance was improved. Finally, simulation results demonstrate the effectiveness of the proposed method.
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Research of Virtual Channels Scheduling Algorithm Based on Priority in Packet Telemetry System
Статья научная
We make research on the virtual channels scheduling algorithm based on priority in packet telemetry system. Probability of occupying physical channel and packets losing rate of the virtual channel with the highest priority are considered, on condition that the packet arrival rate contribution is Poisson contribution. Theoretical analysis and simulation results show that when the running time of the scheduling module is long enough, probability of occupying physical channel by the virtual channel with the highest priority converge on a fixed value. Formulas of calculating packets losing rate are also given, which can offer reference to engineering design.
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Research on Audience Rating Statistics of Two-way Digital TV Based on OpenSSL
Статья научная
The drawback of the present various forms of digital program audience statistical method is that only the traditional phone questionnaire survey, the diary method or the artificial equipment is applied to counting the situation of watching program. By means of combining the timely recognized operation property of various digital terminals and automatic return viewing program feature, a new scheme is proposed to count audience situation for program in two-way digital television network. The main technologies and functions of the scheme are described by introducing audience information gathering mechanisms, security return protocol stack based on openSSL, fusion and automatic transmission and its appropriate statistical methods. Meanwhile, the development of the audience rating statistical system is provided, which is used by some program providers according to this scheme. The experiment and users’ feedback show that this scheme in the lower hardware configuration digital terminals can promptly and accurately count the subscribers watching program and effectively protect audience view information.
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Research on Diffusion Strategy About Resource Index of MP2P
Статья научная
The inherent mobility of nodes leads to frequent changes in network structure and resource location delay larger in MP2P network. Existing search algorithms for MP2P is not efficient enough, and is only for single application model. In this paper an epidemic diffusion strategy about index of resource is proposed to implement diffusion resources to solve low efficiency and long latency positioning defects in a large search. Results demonstrate the principle of the proposed algorithm can improve the resource search efficiency.
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Research on Excessive Road Fuel Problem Based on Extension Strategy Generating Method
Статья научная
The increase of the demand for gasoline in transportation and traffic vehicles results in excessive fuel consumption problem. However, by the extension strategy generating methods, the way of urban transportation changing from bus into metro may be analyzed and evaluated through extension reasoning, extension transformation and optimal calculation in order to solve the problem of excessive fuel consumption of the urban roads.
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Research on Trustworthy Distributed System
Статья научная
To arrive at the goal of intensifying the trustworthiness and controllability of distributed systems, the core function of secure algorithms and chips should be fully exerted. Through building the trustworthy model between distributed system and user behaviors, constructing the architecture of trustworthiness distributed systems, intensifying the survivability of services, and strengthening the manageability of distributed systems, the secure problem of distributed systems is to be radically solved. By setting up the trustworthy computing circumstance and supplying the trustworthy validation and the active protection based on identity and behavior for trustworthy distributed system, we will reach the goal of defending the unaware viruses and inbreak. This research insists that the security, controllability, manageability, and survivability should be basic properties of a trustworthy distributed system. The key ideas and techniques involved in these properties are studied, and recent developments and progresses are surveyed. At the same time, the technical trends and challenges are briefly discussed.
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Research on Wireless Network Security Awareness of Average Users
Статья научная
Network insecurity has become an increasing problem in the world of computer networks. Technical experts have tried to combat this by improving the technical awareness of the threats and technical solutions involved in Wireless Local Networks (WLAN) through technical reports and policy enforcement. The average users' knowledge and awareness of network security, how they react to the warnings and implement security measures is also very important. Current studies on users' awareness of security policies, whether it has been communicated well enough and how aware WLAN users are to the threats and issues involved are still not fully ascertained. To fill this gap it is important to find out the users basic knowledge of the security measures and policies. In this paper, statistical methods were developed and adopted in other to compare the knowledge of Information Technology (IT) related employees and that of non-technical employees on how aware they are of WLAN security threats and security measures. The techniques the paper has adopted revealed the knowledge gap between non-technical and technical users. This revelation is significant and therefore requiring more efficient methods for creating awareness on WLAN threats and countermeasures among average users.
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