Статьи журнала - International Journal of Wireless and Microwave Technologies

Все статьи: 284

A Combining Rate Adaptation Scheme of Channel Coding and Network Coding in None-relay Downlink Wireless System

A Combining Rate Adaptation Scheme of Channel Coding and Network Coding in None-relay Downlink Wireless System

ZiJun Shi, ZhiPing Shi, Gu Li

Статья научная

We propose rate adaptation in the entire downlink process of transmission in channel-network combining coding systems. In current literatures, rate adaptation is discussed in channel coding or network coding separately and in traditional channel-network combining coding cases, network coding rates are generally 1. This paper is based on a one-source multi-destination wireless downlink communication system and a novel scheme of rate adaptation is applied. Our scheme of adaptation works between channel coding rate and network coding rate and its influence on system performance, which is given in form of simulation in the last chapter of this paper, shows that it works well for deducing system BER.

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A Compact Multiband U Shape MIMO Antenna for Wireless Application

A Compact Multiband U Shape MIMO Antenna for Wireless Application

Sachin S. Khade, S.L.Badjate

Статья научная

A compact multiple-input-multiple-output (MIMO) antenna with two dual-branch U shape monopoles is proposed. The isolation between two antenna element is improve by adding three dumbbell shaped DGS between them. This antenna provides multiple frequency bands i.e. 2.4/5.8-GHz for WLAN, 2.5/3.5/5.5-GHz for WiMAX and 3.1–4.8 GHz for lower UWB band operation. The Antenna provides good results with Reflection coefficients < -15 dB and Transmission Coefficients < -30 dB. The results shows that the MIMO antenna can be serve as a phone antenna and it is suitable for integration within portable devices and handheld terminals with total maximum gain up to 4.5 dB and by combining all fields it provides total maximum gain up to 3.2 dBi.

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A Compact, Tri-Band and 9-Shape Reconfigurable Antenna for WiFi, WiMAX and WLAN Applications

A Compact, Tri-Band and 9-Shape Reconfigurable Antenna for WiFi, WiMAX and WLAN Applications

Izaz Ali Shah, Shahzeb Hayat, Ihtesham Khan, Imtiaz. Alam, Sadiq Ullah, Adeel Afridi

Статья научная

This paper introduces a novel 9-shaped multiband frequency reconfigurable monopole antenna for wireless applications, using 1.6 mm thicker FR4 substrate and a truncated metallic ground surface. The designed antenna performs in single and dual frequency modes depending on switching states. The antenna works in a single band (WiMAX at 3.5 GHz) when the switch is in the OFF state. The dual band frequency mode (Wi-Fi at 2.45 GHz and WLAN at 5.2 GHz) is obtained when the switch is turned ON. The directivities are: 2.13 dBi, 2.77 dBi and 3.99 dBi and efficiencies: 86%, 93.5% and 84.4% are attained at frequencies 2.45 GHz, 3.5 GHz and 5.2 GHz respectively. The proposed antenna has VSWR< 1.5 for all the three frequencies. The scattering and far-field parameters of the designed antenna are analyzed using computer simulation technology CST 2014. The performance of the proposed antenna is analyzed on the basis of VSWR, efficiency, gain, radiation pattern and return loss.

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A Composite Heterostructure Mesh-shaped Patch Antenna Based on Left Handed Material

A Composite Heterostructure Mesh-shaped Patch Antenna Based on Left Handed Material

Ji-jun Wang, Zhi-pan Zhu

Статья научная

In this paper, a composite heterostructure mesh-shaped patch antenna based on left handed material (LHM) is presented. The method of finite difference time domain (FDTD) is used. The results show that electromagnetic wave resonance occurs near 4.52 GHz, where the equivalent permittivity and permeability of composite material are both negative. The composite antenna’s gain improves 9.047 dB, its return loss reduces 20.26 dB compared to the conventional antenna’s ones. The results indicate that this composite patch antenna system can reduce return loss of the antenna and increase the gain obviously.

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A Comprehensive Survey of Location Based Routing in Vehicular Networks

A Comprehensive Survey of Location Based Routing in Vehicular Networks

Vikram Dhiman, Ikjot Saini, Manoj Kumar

Статья научная

Vehicular network is the real time network formed by the highly dynamic nodes. This environment of VANET along with the fixed geographical mapping of roads slows down the delivery of the message in case of unicast and broadcast. When unicast is applied then the latency increases significantly as hop count increases. While broadcast make use of the network resources which degrades the performance by decreasing the efficiency of the network. However, multicast is proposed as the parameter to enhance the performance by introducing multicasting trees. This strategy is applied for maintaining the vehicular nodes in a multicast tree manner which will provide single path between two vehicles in the tree. Further, in case of the link failures, tree partitions and reconfiguration is needed this induces to have very low latency and reduces packet overhead. Various location based routing protocols are discussed which reveals different aspects and applications of variety of routing protocols relying on the location information.

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A Comprhensive CBVR System Based on Spatiotemporal Features Such as Motion,Quantized Color and Edge Density Features

A Comprhensive CBVR System Based on Spatiotemporal Features Such as Motion,Quantized Color and Edge Density Features

Kalpana S.Thakre, Archana M.Rajurkar

Статья научная

Rapid development of the multimedia and the associated technologies urge the processing of a huge database of video clips. The processing efficiency depends on the search methodologies utilized in the video processing system. Use of inappropriate search methodologies may make the processing system ineffective. Hence, an effective video retrieval system is an essential pre-requisite for searching relevant videos from a huge collection of videos. In this paper, an effective content based video retrieval system based on some dominant features such as motion, color and edge is proposed. The system is evaluated using the video clips of format MPEG-2 and then precision-recall is determined for the test clip.

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A Data Flow Behavior Constraints Model for Branch Decision-making Variables

A Data Flow Behavior Constraints Model for Branch Decision-making Variables

Lu Yan, Wang Dan, Zhao Wen Bing

Статья научная

In order to detect the attacks to decision-making variable, this paper presents a data flow behavior constraint model for branch decision-making variables. Our model is expanded from the common control flow model, it emphasizes on the analysis and verification about the data flow for decision-making variables, so that to ensure the branch statement can execute correctly and can also detect the attack to branch decision-making variable easily. The constraints of our model include the collection of variables, the statements that the decision-making variables are dependent on and the data flow constraint with the use-def relation of these variables. Our experimental results indicate that it is effective in detecting the attacks to branch decision-making variables as well as the attacks to control-data.

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A Density Control Algorithm For Wireless Sensor Network

A Density Control Algorithm For Wireless Sensor Network

Danyan Luo, Haiying Zhou, Zhan Zhang, Decheng Zuo

Статья научная

If all nodes of a sensor network worked simultaneously, not only there would be a lot of redundant information, but also they would have great adverse impact on network throughput, bandwidth, latency, energy and network lifetime. Consequently, density control technology is necessary for sensor networks, because it can reduce the number of active sensor nodes under the precondition of ensuring network coverage and network connectivity. This paper proposes SNDC (Sensor Network Density Control), a location-free and range-free density control algorithm for wireless sensor network to keep as few as possible sensors in active state to achieve an optimal complete connected coverage of a specific monitored area by periodically sending three beacons of different transmission ranges. Inactive sensors can turn off sensing modules to save energy and sleep. Simulation results show that this algorithm can prolong the network lifetime and guarantee the small number of active nodes and complete network coverage.

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A Design Approach of GSM, Bluetooth and Dual band Notched UWB Antenna

A Design Approach of GSM, Bluetooth and Dual band Notched UWB Antenna

Durgesh Katre, Rekha Labade

Статья научная

In this paper, printed GSM Bluetooth dual band notch UWB antenna is presented. In this prototype corner cut patch for Bluetooth application and dual band notch characteristics of UWB antenna perform by inverting U- Slot in the radiation patch of antenna. With the enclosing of λ/4 stub in the patch of antenna for GSM (1.710-1.885 GHz) band operation. Simulation results show that the antenna yields an impedance bandwidth of 2.4-2.48 and 3-11 GHz with -10 dB reflection coefficients, except for the dual notched bands of 3.3-3.7 for Wi-MAX and 5.15-5.825 GHz for WLAN. The electrical characteristics in frequency domain show suitability of this antenna for use in UWB systems.

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A Design of Trust Degree Transfer Algorithm for P2P Network

A Design of Trust Degree Transfer Algorithm for P2P Network

Wang Hao-yu, Ge Tong-min, Ji Xiao-juan, Hu Bao-an

Статья научная

The design of mechanism is used to calculate node reliability of incredible P2P network. The mechanism through matrix shows the trust relationship between nodes in the network, through matrix operation realizes the trust transfer process fast, and through a trusted server provides calculation service of trust degree for nodes in P2P network.

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A Discussion of a 60GHz Meander Slot Antenna for an RFID TAG with Lumped Element

A Discussion of a 60GHz Meander Slot Antenna for an RFID TAG with Lumped Element

Omrane NECIBI, Abdelhak FERCHICHI, Tan-phu VUONG, Ali GHARSALLAH

Статья научная

In this paper, a novel approach to design an antenna for a transponder in radio frequency identification (RFID) is proposed. This approach is based on using a meander slot patch with a coplanar waveguide excitation (CPW). The RFID frequency chosen is the free 60 GHz band. The proposed circuit does not require complex package or bonding, thanks to the on-chip antenna, and it does not need battery. This technology is characterized by the low-cost, low-weight and low-area occupation. These particular specifications are important of this micro-RFID, especially if produced in large scale for the mass-market. Since the model of antennas in silicon technology is one of the main challenges, particularly for this proposal. The structure is simulated by using Computer Simulation Technology (CST). The antenna size is 1.95 * 1.99 mm2.This proposed antenna presents again which means a possibility to increase the readable range.

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A Group-oriented Access Control Scheme for P2P Networks

A Group-oriented Access Control Scheme for P2P Networks

Wang Xiaoming, Cheng Fan

Статья научная

A group-oriented access control scheme is proposed for P2P (peer to peer) networks. In the proposed scheme, authentication control, admission control and revocation control are used in order to provide security services for P2P networks. Moreover, the proposed scheme can simply and efficient establish share key between two members without interactions, therefore it can perform secure communications with them. The analysis of security and performance shows that the proposed scheme not only can realize authentication and secure communication, but also can easily and efficiently add new group members and revoke malicious group members. Therefore, it is more efficient, and more practical protocol for P2P networks.

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A Hybrid Mimo Technique for Better Ber in High Data Rate Wireless Communication System

A Hybrid Mimo Technique for Better Ber in High Data Rate Wireless Communication System

Kehinde Odeyemi, Erastus Ogunti

Статья научная

The need for high data rate and better quality of service in wireless communications has become imperative in the past few years judging by user demand. Obtaining these requirements has become very challenging for wireless communication systems due to the problems of channel multi-path fading, higher power and bandwidth limitations. One of the most promising solutions to this problem is the Multiple Input Multiple Output (MIMO) system. This paper proposed a combined spatial multiplexing MIMO scheme with beamforming for high data rate wireless communication. The proposed transmission scheme combines the benefits of both techniques resulting in the system ability to transmit parallel data streams as well as provide beamforming gain. Actually, these diverse techniques, share the same requirement of multiple antenna elements, but differ in the antenna element spacing necessary for the different schemes to work. Thus, smart antenna arrays were proposed as a possible solution and were adopted at both the transmitter and the receiver. The proposed hybrid technique provides better Bit Error Rate (BER) performance than the conventional MIMO, spatial multiplexing or beamforming technique alone under the same simulation environment.

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A Linear Polarized Coaxial Feeding Dual Band Circular Microstrip Patch Antenna for WLAN Applications

A Linear Polarized Coaxial Feeding Dual Band Circular Microstrip Patch Antenna for WLAN Applications

Sheikh Dobir Hossain, K. M. Abdus Sobahan, Md. Khalid Hossain, Md. Khalid Hossain Jewel, Rebeka Sultana, Md. Al Amin

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

A Low-Cost Noise Wave Correlator for Noise Parameters Extraction by Cold Noise Power Measurement

Abdul-Rahman Ahmed, Kyung-Whan Yeom

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

A Method of Target Detection in Remote Sensing Image Captured based for Sensor Network

Yingchun Shen, Hai Jin

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 Multi-step Attack Recognition and Prediction Method Via Mining Attacks Conversion Frequencies

A Multi-step Attack Recognition and Prediction Method Via Mining Attacks Conversion Frequencies

MAN Da-peng, LI Xue-zhen, YANG Wu, WANG Wei, XUAN Shi-chang

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

A Multicast Routing Mechanism in Mobile Ad Hoc Network Through Label Switching

Li MengYang, Duan YunNa, Zhang ChunFei

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 Half-blind Algorithm of Smart Antenna for Mobile Terminal

A New Half-blind Algorithm of Smart Antenna for Mobile Terminal

Yuan Li, Wei Zhang, Jia Guo

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

A New Joint Antenna Selection Algorithm Based on Capacity

Li Yuan, Liu Ping, Li Jianlan

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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