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Wireless Information Technology and Systems (ICWITS), 2010 IEEE International Conference on

Date Aug. 28 2010-Sept. 3 2010

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Displaying Results 1 - 25 of 239
  • Steering Committee

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  • Table of contents

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    Freely Available from IEEE
  • Performance evaluation of IEEE 802.16e mobile WiMAX for long distance control of UAV swarms

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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (848 KB) |  | HTML iconHTML  

    The IEEE 802.16e mobile WiMAX standard allows for a wide variety of different application. Especially in cases where people rely on high speed network access in greater areas which is exclusively dedicated to them mobile WiMAX is a viable solution. One of these scenarios is the control of a swarm of miniature unmanned aerial vehicles (MUAV). These flying robots can be used for a wide set of different applications which range from airborne surveillance to traffic control and more. In the AirShield project [1], sponsored by the German Ministry for Education and Research, the MUAV swarm is used to measure the concentration of different harmful substances which occur in the case of fire or a malfunction in industrial facilities. Due to the fact that the clouds of contaminant may travel over several of kilometers a reliable communication system which can handle these distances and furthermore ensures some QoS guarantees is needed. In this paper we investigate in how far mobile WiMAX can ensure these guarantees in terms of packet loss, delay, jitter and throughput under different channel conditions. Therefore a laboratory testbed based on the E6651 mobile WiMAX base station emulator by Agilent Technologies is used for the different measurements. View full abstract»

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  • Systems delay characteristics of a busy-tone protocol in CCA modified, long range IEEE 802.11 networks

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    This paper discusses the delay characteristics and packet drop ratio performance of Busy Tone Multiple Access Protocol (BTMAP) for distances up to 48Km in IEEE 802.11 networks. The impact of the Contention Window (CW) is discussed. We note that a larger CW will increase the mean packet delay but decrease the packet drop ratio. Long range also significantly degrades the delay and packet drop ratio performance of the BTMAP, however, with the same number of users, a larger cell will cause higher drop ratio but shorter delay. This indicates that larger distances increasingly corrupt packets and are problematic to long range communications. At extremely long range (48Km), by choosing a user number less than CW, it is still possible to control the mean packet delay to under 100ms which is acceptable for VoIP networks, but the packet drop ratio is remains high due to transmission delay. View full abstract»

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  • Reconfigurable dual band microstrip patch antenna for Software Defined Radio applications

    Page(s): 1 - 4
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (387 KB) |  | HTML iconHTML  

    In this paper, a reconfigurable microstrip patch antenna with RF pin diode switches is implemented for dual band of 2.4 GHz and 5.6 GHz Software Defined Radio (SDR) applications. For the dual band SDR system, the use of a single antenna with a wide bandwidth to cover both of the bands can be limiting for low power level signal applications due to wideband noise. A reconfigurable nested microstrip patch antenna is designed on a Rogers 5880 RT/DUROID substrate which is fed by a coaxial probe from the back side of the grounded substrate. RF switching circuitry involves four RF pin diodes at each side of the inner patch. The dual bands of 2.4 GHz and 5.6 GHz frequency operation can be simply obtained by switching the PIN diodes on and off. The antenna is well matched and achieves approximately 7 dBi simulated gain at both frequency bands. Simulation results show that the nested patch antenna is suitable for dual band SDR applications. View full abstract»

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  • Linear combination based energy detection algorithm under low SNR for cognitive radios

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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (303 KB) |  | HTML iconHTML  

    In paper proposes a linear combination (LC) algorithm instead of the CFAR criterion and the CDR criterion in energy detection. The LC algorithm linearly combines the probability of detection and the probability of false alarm, and optimizes them simultaneously. Based on the LC algorithm, the closed-form expression for the optimal decision threshold of energy detector is derived. Simulation results are presented to verify the effectiveness of the proposed algorithm. View full abstract»

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  • Design considerations of 3-D single package communicator (SPC) for quad-band WCDMA/GSM cellular phone

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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (319 KB) |  | HTML iconHTML  

    A complete single package communicator (SPC) designed and implemented for 3G modem in 400 mm2 size and 1.3 mm height, for the first time is presented. With the help of 3-D technology, development of highly integrated active/passive components and use of latest packaging technology, the design was doable. Optimization of the RF performance of all GSM and WCDAM channels was obtainable despite the small form factor. The design was taped out. View full abstract»

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  • A dual-band tri-element elliptical patch array antenna for WLAN access-points

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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (374 KB) |  | HTML iconHTML  

    In this paper a dual WLAN band, three elements circular patch array antenna with a novel radial tapered feed network introduced. Although the proposed antenna with back reflector has been chosen as main prototype for optimization, fabrication and test, observed that this antenna in without reflector mode can also operated with acceptable impedance performance in WLAN2.4/5.8GHz bands. In reflector mode, the proposed antenna recognize a band tunable antenna depend on the distance between of reflector plane and antenna. View full abstract»

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  • Tunable lumped-element notch filter with constant bandwidth

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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (631 KB) |  | HTML iconHTML  

    A varactor-tuned first-order (two-resonator) lumped-element absorptive notch filter with tunable operating frequency and constant absolute bandwidth has been introduced, along with an approach to its design. To reduce signal voltage across individual varactors, it is suggested to add additional pairs of stacked varactors in parallel, rather than in series. A cascade of three first-order subcircuits is used to make a third-order filter with useful levels of frequency selectivity and stopband bandwidth and attenuation, with a wide tuning range, and with constant -30dB and -3dB bandwidths. Filters of this type are expected to find use in miniature low-power receivers that must function in dynamic operating environments that may have relatively large narrowband interference. View full abstract»

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  • Compact WCDMA and WLAN antenna for mobile equipment

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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (398 KB) |  | HTML iconHTML  

    A compact, low-profile, planar, microstrip fed, low-cost antenna which can be integrated easily with RF circuitry on the same printed circuit board has been designed for 3G wideband code division multiple access (WCDMA) mobile and WLAN applications.The proposed antenna fills this gap with a small footprint of 18x21 (mm2).The antenna is built on FR-4 type substrate, and the radiating patch is loaded by another FR-4 layer on top. View full abstract»

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  • 5.8-km 10-Gbps data transmission over a 120-GHz-band wireless link

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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (612 KB) |  | HTML iconHTML  

    We have developed 120-GHz-band wireless equipment that can transmit 10-Gbit/s data signal over a distance of more than 5 km. In order to increase the output power of the120-GHz-band wireless equipment, we used a millimeter-wave amplifier that integrates 0.08-μm-gate-length InGaAs/InP composite-channel high-electron-mobility transistors. The output power of the wireless equipment becomes 16 dBm. The wireless equipment can handle data rates of 1 Mbit/s to 11.1 Gbit/s and transmit 10-Gbit/s-class data signals with and without forward error correction (FEC). We conducted wireless data transmission experiments over a distance of 4.8 km and 5.8 km and succeeded in the error-free data transmission of 10-Gbit/s data with FEC. View full abstract»

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  • Capacitance value control for metamaterial reflectarray using multi layer mushroom-structure with parasitic element

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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (813 KB) |  | HTML iconHTML  

    This paper proposes novel reflectarray design using multi layer mushroom structure with parasitic element based on capacitance value control of LC resonant circuit model. From the study of LC resonant circuit model, this paper shows the parallel setting capacitance value can be theoretically controlled by that the parasitic layer number. Next, this paper shows novel reflectarray design method for -70 degree vertical beam control mushroom reflectarray for vertical polarization by focusing on capacitance value. Finally, this paper shows proposed design has good performance and both simulated and experiment results shows good agreement. View full abstract»

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  • Horizontally polarized, omnidirectional antenna with a single feed

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    This paper proposes a novel antenna, which overcomes the above-mentioned issues. The proposed antenna is composed of arc strips. These strips are excited by a single coaxial line. Unlike the antenna in, no reactive elements are used. The proposed antenna is designated as the HP-ARC antenna (horizontally polarized arc antenna), in order to distinguish it from the HoPOMin. View full abstract»

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  • Concept for electronic calibration of A CMOS voltage reference

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    In this paper an approach for a CMOS voltage reference with the ability to calibrate both voltage over temperature behavior and absolute voltage value is presented. This is achieved by electronic controlled trimming of resistances in the PTAT current source and output amplifier. For the transistors in the PTAT current source, the diode connected reference source and the error amplifier a common size of width W = 1μm and length L = 4μm was chosen. The design has a nominal total current consumption of 3.4μA and operates at a minimum supply voltage as low as 800mV for the chosen Vref2 of 700mV. The design can be optimized for even lower current consumption by using higher resistances as well as narrower and/or longer transistors. However, such an adaption increases the chip area due to the larger size of both resistors and FETs. View full abstract»

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  • Modified BOR-CROSS antenna

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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (271 KB) |  | HTML iconHTML  

    This paper presents a low-profile base station antenna, called the MBOR-CROSS, which is a modification of the BOR-CROSS developed using the design concept of the BOR-SPR. The MBOR-CROSS is composed of a conducting BOR and crossed strip plates. This MBOR-CROSS is designed for a frequency range of 470 MHz to 2625 MHz. The analysis results of the MBORCROSS are presented and discussed. View full abstract»

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  • Wireless network-to-network localization for measuring the spatial position and orientation of vehicles

    Page(s): 1 - 4
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (942 KB) |  | HTML iconHTML  

    In the current article a network based approach and system setup is introduced that allows for a precise measurement of both, the spatial position and the orientation of mobile objects. A multidimensional scaling based algorithm is applied to solve the challenging localization task. The feasibility of the approach is proved experimentally with a 5.8 GHz localization network for a vehicle localization application. View full abstract»

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  • Characteristic comparisons between array, reflectarray and elliptic reflector antennas in RFID near-field focused communications

    Page(s): 1 - 4
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (409 KB) |  | HTML iconHTML  

    This paper presents characteristic comparisons between array, reflectarray and elliptic reflector antennas which can be implemented to radiate fields focused in the near zone of antenna aperture. A potential application, as to be demonstrated later in this paper, is for RFID reader applications at 2.4 GHz. The comparisons include beamwidth, field strength and contoured patterns, which allows one to justify the selection of a proper antenna type for practical applications. View full abstract»

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  • Cross-layered design of security scheme for cooperative MIMO sensor networks

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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (481 KB) |  | HTML iconHTML  

    In this paper, the authors propose a cross-layer security scheme for virtual MIMO networks. The scheme combines cryptographic technique implemented in higher layers with data assurance analysis at the physical layer to provide better security. The scheme can, of course, be used for a traditional non-cooperative MIMO network. First, the authors show an efficient key management system that can provide secured communication and routing with a small number of keys shared between the clusters which cooperate on data transmission and reception. Then, the authors show a novel approach that can detect and identify compromised nodes in transmission process at physic layer. By key revocation the compromised nodes are discarded and the clusters/virtual MIMO nodes are self-reconfigured. The primary evaluation shows that the key management system can secure communication and routing with small number of keys, and the approach for detecting compromised nodes is very effective. View full abstract»

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  • Analysis of tapped-in coupling between combline resonators applicable in wideband filter designs

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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (392 KB) |  | HTML iconHTML  

    In this work, a simple circuit model comprised only of lumped elements is developed to model the inter-resonator tapped-in coupling mechanism between symmetric resonators. This circuit model is utilized to explain the coupling phenomena. Mathematical relations are derived to express the coupling and resonant frequency in terms of the circuit-model elements. Derivatives of these expressions are used to describe the behavior of coupling and resonant frequency in terms of circuit elements. It is noted that the circuit model and the results introduced here are used in the development of circuit-based CAD tool to speed up the design of microwave combline filters. Finally, the measurement results are provided to confirm the simplicity of adjusting coupling strength between combline resonators using the proposed coupling mechanism. View full abstract»

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  • Relative-localization identification of random distributed wireless sensor network nodes

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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (361 KB) |  | HTML iconHTML  

    Localization services are one of the most important services provided by wireless sensor networks. In this paper, a relative-localization identification of random deployed non-anchored nodes will be presented. Based on relative RSSI information, the system can identify which sensor nodes are placed in locations planned on map. The method can let user put any nodes anywhere (random distributed), and the nodes will locate themselves without knowing the coordinate (absolute or relative) beforehand. The algorithm and experimental verification of this method will all be detailed in this paper. View full abstract»

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  • Novel compact narrow-band band- pass filter (NB BPF) using microstrip closed- loop ring resonators for personal communication systems (PCS's)

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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (144 KB) |  | HTML iconHTML  

    In this paper, a novel compact elliptic-function narrow-band band-pass filter is developed using a new configuration of coupled lines to further enhance the coupling strength at the input and output terminals. It is shown that this proposed model provides an effective and beneficial flexibility to control the performance of the filter to realize a narrow-band band-pass filter with improvement in insertion and return losses as well as 3-dB bandwidth less than 2%. The proposed NB band-pass filter is designed and simulated on a 50-mil-thichness substrate with a dielectric constant of 10.5. View full abstract»

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  • Sensors set selection under sensing performance constraints

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    The number of cooperative sensors to use is a compromise between sensing performance and resources usage efficiency. The definition of the optimal cooperative sensor set is given out firstly and then a greedy selection algorithm for the optimal cooperative sensor set is proposed which can use fewest cooperative sensors to maximize the resources usage efficiency, while still having enough for the sensing performance constraints. Analysis and numerical results illustrate the effectiveness and reliability of the proposed selection algorithm. View full abstract»

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  • Improvement of the throughput-SNR trade-off using a 4G adaptive MCM system

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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (450 KB) |  | HTML iconHTML  

    The MIMO-OFDM Adaptive MCM System changes MIMO scheme, channel coding rate, and modulation scheme, adaptively, according to the channel conditions. And the addition of Pre-coding and Antenna Subset Selection assures a better performance and higher data rate. The MIMO-OFDM Adaptive MCM System achieves a better average throughput performance than a Non Adaptive-MCM system; as SNR increases, the throughput increases almost linearly. Based on the simulation results, we conclude that the proposed MIMO-OFDM Adaptive MCM System represents a feasible solution for improving the throughput-SNR tradeoff in the next generation of mobile communication systems. View full abstract»

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  • Performance analysis of an adaptive-MCM system with combining AMC and MIMO schemes

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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (288 KB) |  | HTML iconHTML  

    In this paper, we proposed a system that combines AMC and MIMO schemes. While conventional AMC system changes only the coding rate and modulation, the proposed AdaptiveMCM system also selects the MIMO scheme (diversity, multiplexing) according to channel condition. Furthermore, by applying pre-coding and antenna subset-selection we not only produce optimal performance but also increase the data rate. In case of Non-Adaptive-MCM, the simulation results show that even thought, this system secures enough SNR, and its maximum throughput is limited. As for the Adaptive-MCM System, the simulation shows an overall average data rate increase, and a maximum throughput of 1440kbps that can be achieved because the schemes corresponding to the MCM levels are assigned dynamically. This probes that the Adaptive-MCM system increases the average data rate by improving the trade-off between SNR and throughput. View full abstract»

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  • Tracking antenna for mobile bi-directional satellite communications in Ka-band

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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (422 KB) |  | HTML iconHTML  

    The paper describes an operational Ka-band satellite antenna that provides pointing error information for land-mobile applications. The antenna performs a conical scan of the beam pattern and derives tracking signals by means of an analogue circuit. This work contributes to the development of a mobile satellite terminal for communication in disaster scenarios. View full abstract»

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