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Radio and Wireless Conference, 1999. RAWCON 99. 1999 IEEE

Date 1-4 Aug. 1999

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Displaying Results 1 - 25 of 75
  • RAWCON 99. 1999 IEEE Radio and Wireless Conference (Cat. No.99EX292)

    Publication Year: 1999
    Request permission for commercial reuse | PDF file iconPDF (715 KB)
    Freely Available from IEEE
  • Multibeam antenna with decision-feedback equalization for home wireless communications

    Publication Year: 1999, Page(s):23 - 26
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (327 KB)

    A multibeam beamformer is considered for the base station in a single-cell 100 Mbps TDMA/QPSK indoor wireless network at 24 GHz. Using a previously reported statistical propagation model that forms clusters of paths in angle and delay, we evaluate the performance of an RF beamformer in combination with a decision feedback equalizer (DFE) for indoor wireless communications. Based on the model, we c... View full abstract»

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  • Seasonal variability of a local multi-point distribution service radio channel

    Publication Year: 1999, Page(s):211 - 214
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (144 KB)

    This paper investigates the seasonal variability of an LMDS radio channel obscured by vegetation. A 1-km, 28.8 GHz radio link was established and monitored during spring and fall seasonal changes. The radio path was obscured by two deciduous trees but had more then two Fresnel zones of clearance over the roof of an adjacent building. Seasonal signal variability was caused by the presence or absenc... View full abstract»

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  • Antenna downtilt effects on CDMA cell-site capacity

    Publication Year: 1999, Page(s):99 - 102
    Cited by:  Papers (6)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (412 KB)

    Antenna downtilt is often used in cellularized mobile wireless communications systems to reduce inter-cell interference, particularly in a CDMA-based network where all call traffic in all cell sites is simultaneously supported using the same carrier frequency. While the inter-cell interference is indeed reduced through such downtilt the sectorization efficiency may also be reduced with increased d... View full abstract»

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  • The asymptotic reduction of PO surface integral

    Publication Year: 1999, Page(s):207 - 210
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (140 KB)

    Modified edge representation (MER) empirically proposed by one of the authors has remarkable accuracy for the surface to line integral reduction of radiation integrals in scattering problems for a near source. This paper gives the mathematical derivation of the MER for the first time. Numerical results for the diffraction of the electric dipole waves from the rectangular flat plate with the surfac... View full abstract»

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  • System optimization with active power control during high traffic in cellular CDMA

    Publication Year: 1999, Page(s):93 - 97
    Cited by:  Papers (5)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (236 KB)

    A concept of active power control for the CDMA system is described through which the dynamic optimization of the system can be performed for the time-varying cellular traffic demands. In particular, the capacity of a code division multiple access system is optimized for high traffic concentrated areas by using an active power control approach. As a simulation example of this approach, an optimized... View full abstract»

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  • Full-wave study on the accuracy of ray-tracing in multipath environments

    Publication Year: 1999, Page(s):203 - 206
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (204 KB)

    The article examines the accuracy of the commonly used ray-tracing technique as local scatterers become electrically small, a situation often found in indoor environments. In this case, the high frequency approximation inherent to ray-tracing may not be satisfied and the accuracy of the method may be compromised. Accuracy is quantified here by comparison to a full-wave simulation techni... View full abstract»

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  • Performance of an optical CDMA system with turbo code

    Publication Year: 1999, Page(s):89 - 92
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (228 KB)

    In this paper, performance of an optical CDMA system with turbo code is analyzed and simulated. It is assumed that optical channel is an intensity modulated (IM) channel and direct-detection scheme is employed to detect the received optical signal. The modulation scheme used is binary-pulse-position-modulation (BPPM). From the simulation results, it is shown that turbo coding offers considerable c... View full abstract»

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  • FDTD analysis of mutual coupling in combline filter design

    Publication Year: 1999, Page(s):199 - 202
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (232 KB)

    The mutual coupling between two cavities in the combline filter structures is calculated by the FDTD method in combination with the discrete FFT. A conventional Yee's scheme is implemented and a staircase approximation of the cylindrical resonator is used. Very close agreement between measured and simulated results is demonstrated View full abstract»

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  • Frequency domain reciprocal modulation (FDRM)

    Publication Year: 1999, Page(s):129 - 132
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (180 KB)

    Frequency domain reciprocal modulation is a new digital transmission technique that offers an advantage in radio frequency channels afflicted with dynamic multipath. Multipath is a linear distortion that is also known as echoes or ghosts. Bandwidth-efficient digital transmission is very difficult through a channel that has moving ghosts because adaptive equalizers frequently cannot adapt fast enou... View full abstract»

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  • Radio aspects of a stratospheric broadband wireless system

    Publication Year: 1999, Page(s):1 - 2
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (92 KB)

    The High Altitude Platform Stations (HAPS) is a novel telecommunications network, which employs a proprietary stratospheric platform technology to provide broadband wireless communications services around the world. The stratospheric platform is a super-pressurized helium-filled solar/fuel-cell powered airship with enough payload and power capacity to support all of a metropolitan area's broadband... View full abstract»

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  • Assessment of cochannel interference in fixed wireless cellular systems

    Publication Year: 1999, Page(s):13 - 16
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (272 KB)

    In wireless cellular systems cochannel interference is the limiting factor in determining the capacity. Fixed wireless systems such as MMDS and LMDS are no exception to this rule. We analyzed the signal-to-interference ratio in a highly-overlapped cellular architecture. Through macro diversity, such a cellular architecture can provide significant diversity gains but it is vulnerable to excess coch... View full abstract»

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  • SiGe BiCMOS technology for RF device and design applications

    Publication Year: 1999, Page(s):281 - 284
    Cited by:  Papers (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (164 KB)

    In this paper we demonstrate the advantages of SiGe BiCMOS for wireless designers and discuss several wireless circuits currently available in this technology as illustrations of the value of designing in SiGe BiCMOS. Finally, we discuss the future evolution of the technology View full abstract»

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  • EM simulations for radio and wireless on a PC

    Publication Year: 1999, Page(s):175 - 178
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (264 KB)

    An electromagnetic (EM) computational tool for radio and wireless applications is presented. The generality, versatility, accuracy, and practicality of the method and code are demonstrated on five very diverse, electrically large and complex antenna problems. The examples are: a dipole antenna array backed by an optimal 220-degree inverse corner reflector; an X-band reflector antenna modeled after... View full abstract»

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  • Mobile ranging with low accuracy clocks

    Publication Year: 1999, Page(s):85 - 88
    Cited by:  Papers (1)  |  Patents (18)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (272 KB)

    Our position location technique provides location information within milliseconds and is integrated in a handheld, direct sequence spread spectrum (DSSS), communications system. We use a standard DSSS waveform, with a state-of-the-art chipping rate to provide a position location capability to an accuracy of less than one meter in a severe multipath environment. We use a two-way time-of-arrival (TO... View full abstract»

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  • Q-factors of a ring dielectric resonator in an MIC structure

    Publication Year: 1999, Page(s):195 - 198
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (128 KB)

    For a ring dielectric resonator in a microwave integrated circuit (MIC) environment, the conductor, dielectric, and unloaded Q-factors of the TE01δ mode are derived from the field analysis. A dielectric Q-factor is newly defined for two dielectric materials which consist of a dielectrics of a ring resonator and that of a substrate. The calculated values of the unloaded Q-factor ar... View full abstract»

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  • Nonlinear equalization of propagation-path delay distortion in the frequency domain (MLSpE: maximum likelihood spectrum estimation)

    Publication Year: 1999, Page(s):125 - 128
    Cited by:  Papers (8)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (184 KB)

    In the equalization methods, nonlinear equalization is known to be more effective than linear equalization. As one of the most effective nonlinear equalization methods in the time domain, the maximum likelihood sequence estimation (MLSE) method has been commonly used. In the MLSE, equalization is performed by making the replica of transmitted symbols. In this paper, the author presents a frequency... View full abstract»

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  • Interconnection parasitic effects on optical communication circuit performances

    Publication Year: 1999, Page(s):267 - 270
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (140 KB)

    The influence of parasitic elements such as wire bonding and ribbon connections on laser driver performances is analysed. In order to minimize parasitic effects, an interconnection geometry is suggested for a best module response. A simplified method based on the partial element equivalent circuit (PEEC) has been established to model and characterize the inductance of these parasitic elements. Ana... View full abstract»

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  • Radio system design for broadband residential access

    Publication Year: 1999, Page(s):31 - 34
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (216 KB)

    This paper reviews the requirements and design for a low cost residential broadband wireless access system for use in the MM-wave bands (24-42 GHz). The proposed system design is based on a downlink utilizing time division multiplexing and packet transmission using the MCNS DOCSIS standard. In the upstream direction time division multiple access is used for data packet bursts also following the MC... View full abstract»

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  • Delay profile measurement system for microwave mobile communications and delay characteristics in an urban environment

    Publication Year: 1999, Page(s):163 - 166
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (196 KB)

    We have developed a system for measuring the microwave broadband propagation delay profile over 100-MHz spread bandwidths in the 3, 8, and 16 GHz bands. Experiments confirmed the system has a time resolution of 20 ns, maximum measurable delay of 40 μs, relative amplitude error of within 3 dB and dynamic range of over 60 dB. We used the system to measure line-of-sight delay profiles in an urban ... View full abstract»

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  • Watt level GaAs PHEMT power amplifiers 26 GHz and 40 GHz for wireless applications

    Publication Year: 1999, Page(s):309 - 312
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (196 KB)

    The authors report on the design, fabrication and performance of 1 W amplifiers for 26 GHz and 40 GHz. The design approach uses standard MMIC elements: microstrip transmission lines, MIM capacitors, through-the-substrate vias for low impedance ground connection, two metal levels, air bridge crossovers and 75 μm substrates. The substrate material is grown by MBE, and for higher output power has ... View full abstract»

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  • Analysis of mobile positioning measurements in CDMA cellular networks

    Publication Year: 1999, Page(s):73 - 76
    Cited by:  Papers (3)  |  Patents (8)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (164 KB)

    Mobile positioning is one of the services which can be offered by CDMA network operators. There are several mobile positioning applications such as, locating lost or stolen mobiles, emergency calls, street directory applications and CDMA network self optimisation. The Federal Communications Commission (FCC) in the USA has mandated that all mobile phones will have a mobile positioning capability fo... View full abstract»

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  • A tunable low power BiCMOS continuous-time Gm-C lowpass filter

    Publication Year: 1999, Page(s):219 - 222
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (184 KB)

    A monolithically integrated 5th order lowpass filter with a tunable cutoff frequency is presented. The cutoff frequency can be tuned via a control voltage between 30 kHz and 180 kHz. This circuit may serve as channel selecting filters in direct conversion receivers for various cellular radio services with different bandwidth (e.g. IS-54, GSM, etc.). The main design goals are low power c... View full abstract»

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  • WWW service in 3G wireless CDMA systems

    Publication Year: 1999, Page(s):137 - 140
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (172 KB)

    Third generation (3G) wireless systems will provide all types of data services. This paper investigates two techniques of simultaneously providing packet data services to many users by using a single high-speed CDMA channel. WWW browsing is one of the suitable services for using these techniques. Multiple WWW browsing users within a cell will share a CDMA channel. System performance in terms of av... View full abstract»

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  • Simulations of channel capacity and frequency reuse in multipoint LMDS systems

    Publication Year: 1999, Page(s):9 - 12
    Cited by:  Papers (1)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (200 KB)

    The results of several studies of microwave LMDS system capacity are presented. Assuming standard multi-sector hub site configuration with four sectors with alternating polarizations, and cross polarization uplinks and downlinks, the cumulative distribution of link availability in the system is calculated as a function of system loading, cross polarization rejection, and required C/(I+N) performan... View full abstract»

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