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Wireless Technology, 2005. The European Conference on

Date 3-4 Oct. 2005

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Displaying Results 1 - 25 of 149
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  • The European Conference on Wireless Technology

    Page(s): 0_1
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  • 2005 European Conference on Wireless Technologies

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  • Copyright page

    Page(s): ii
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  • Introduction to the 2005 European Conference on Wireless Technology

    Page(s): iii
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  • ECWT 2005 Committees

    Page(s): iv
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  • List of technical reviewers

    Page(s): v
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  • Sessions

    Page(s): vi
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  • An overview of turbo codes and their applications

    Page(s): 1 - 9
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (359 KB) |  | HTML iconHTML  

    More than ten years after their introduction, turbo Codes are now a mature technology that has been rapidly adopted for application in many commercial transmissions systems. This paper provides an overview of the basic concepts employed in convolutional and block turbo codes, and review the major evolutions in the field with an emphasis on practical issues such as implementation complexity and high-rate circuit architectures. We address the use of these technologies in existing standards and also discuss future potential applications for this error-control coding technology View full abstract»

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  • Table of contents

    Page(s): 11 - 18
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  • Author index

    Page(s): 19 - 20
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  • Characterization and modeling of the MIMO propagation channel: an overview

    Page(s): 11 - 14
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (235 KB) |  | HTML iconHTML  

    This paper deals with several aspects relative to the multiple-input multiple-output (MIMO) propagation channel. Different approaches used to model the MIMO channel are first presented. Then, the different measurement techniques used in order to characterize the propagation channel are described. Measurement campaigns made in urban environments have been analyzed to obtain the relevant statistical parameters of the channel. These results make it possible to discuss the integration of MIMO techniques in practical wireless communication systems View full abstract»

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  • A transceiver module for quad band EGPRS (GSM/GPRS/EDGE) class 12 applications

    Page(s): 15 - 18
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (290 KB) |  | HTML iconHTML  

    This paper describes the design, technology selection and performance of a compact mixed signal transceiver module for wireless quad band EGPRS applications. The module uses 6 layers of HDI-organic substrate, integrates three IC technologies - 0.18 mum RF-CMOS for RF/Analog, 0.13 mum CMOS for mixed signal analog/digital/DSP and GaAs for an integrated passive devices (IPD) quad band balun - plus surface mount devices (SMD) for loop filter and RF bypass. It has the complete transmit line up from digital bits (as per DigRF standard version 1.1) to power amplifier interface, as well as receive function from LNA inputs to bits (per DigRF standard) View full abstract»

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  • Highly linear IQ downconverter for reconfigurable wireless receivers

    Page(s): 19 - 22
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (312 KB) |  | HTML iconHTML  

    This paper describes a design of an active, low voltage, reconfigurable IQ downconversion mixer based on a current-mode output architecture. The I/Q mixer, fabricated in 0.13 mum RF CMOS technology, operates at 1.5 V with a moderate current consumption of 8 mA. It achieves an out-of-band input-referred 1 dB compression point of -7 dBVrms (+6 dBm in 50 Omega system) and an out-of-band IIP3 of +2 dBVrms (15 dBm), enabling its utilization in multi-band, multi-standard receivers with decreased RF selectivity. Experimental results confirm the superior large signal handling capabilities of the mixer View full abstract»

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  • Antenna switch linearity requirements for GSM/WCDMA mobile phone front-ends

    Page(s): 23 - 26
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (341 KB) |  | HTML iconHTML  

    The design of the RF front-end part in modern cellular phones is becoming increasingly complex and demanding due to increasing number of frequency bands and modes that the phone needs to operate in. One of the main components of the RF front-end is the antenna switch that selects which TX/RX path is connected to the antenna. This paper considers the linearity requirements for antenna switches used to switch full-duplex WCDMA signals. The most demanding linearity requirement for WCDMA is shown to be the RX out-of-band blocking performance. The out-of-band blocking problem is shown to be caused by the three dominating intermodulation distortion (IMD) mechanisms of the switch. The switch IMD performance is also shown to depend on the relative phase shift between switch and duplexer. Two measurement setups are shown with measured results View full abstract»

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  • A 2.14 GHz, 0.78 dB noise figure CMOS low noise amplifier

    Page(s): 27 - 30
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (299 KB) |  | HTML iconHTML  

    This work presents a 2 GHz LNA designed for UMTS mobile terminals. The circuit is implemented in a 0.13 mum CMOS technology. In design methodology small signal and noise parameters of the amplifier are combined, and pad capacitance is used for improving the noise performance. The designed amplifier shows 0.78 dB noise figure and 12 dB gain at 2.14 GHz for 3.5 mA supply current and 1.2 V supply voltage View full abstract»

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  • An extremely low power 2 GHz CMOS LC VCO for wireless communication applications

    Page(s): 31 - 34
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (304 KB) |  | HTML iconHTML  

    An extremely low power low phase noise CMOS LC voltage controlled oscillator (VCO) has been fully integrated in a commercial 0.18 mum CMOS process. To achieve low power and low phase noise, a complementary NMOS and PMOS cross-coupled differential LC structure is used. The LC tank is composed of octagonal-shaped inductors with 2 mum Al metal and standard NMOS varactors. The measured phase noise is -111 dBc/Hz at 1 MHz offset from a 1.87 GHz carrier when the VCO core consumes only a 0.5 mW power from 0.9 V supply. The power consumption of 0.5 mW is the lowest reported in the literature for LC VCOs. This VCO has a figure of merit of -180 dBc/Hz and achieves a 7 % tuning range with a control voltage ranging from 0 ~ 1.4 V, while maintaining a tuning sensitivity of 93 MHz/V over its entire frequency range View full abstract»

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  • Optimised scanning of a visibility graph data structure for efficient ray-tracing

    Page(s): 35 - 38
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (484 KB) |  | HTML iconHTML  

    An efficient way to implement a ray tracing is to use the visibility relations between geometric primitives, as in Hoppe's work. Authors present a novel approach subdivided in two steps. First, a graph is computed to encode the visibility relations. This preprocess is easier and less restrictive than the Hoppe's one. Moreover, the computation precision can be tuned to satisfy a required accuracy, or the scene complexity. Secondly, an optimised graph scanning is used to reduce the computation time of the deterministic ray tracing. An interesting property is that the graph scanning does not have any impact on the calculation accuracy. As a consequence, the precision wanted by the user is preserved. In addition, it can be used in conjunction with other techniques to speed-up again the computation. This leads to a flexible tool able to compute efficiently and precisely coverage zone and impulse responses, as needed for channel characterization for instance View full abstract»

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  • Clusterization of the propagation channel in urban macrocells at 2 GHz

    Page(s): 39 - 42
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (355 KB) |  | HTML iconHTML  

    A directional wideband measurement campaign has been performed in urban macrocells at 2 GHz using a channel sounder and a 8-sensor linear antenna array at the base station. Directions of arrival at the base station were estimated by beamforming using the antenna array. Directions of arrival at the mobile were estimated by beamforming using parts of the measurement route. Azimuth-delay power profiles at the base station and mobile are given to show the clustered structure of the propagation channel in urban macrocells environments. This paper also presents a fast and simple method to extract clusters from a large amount of data View full abstract»

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  • The modelling of high-rise buildings' influences for application in a semi-deterministic propagation model

    Page(s): 43 - 46
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (263 KB) |  | HTML iconHTML  

    In this paper a newly applied approach to model the effects of high-rise blocking buildings near a base station (BS) in cellular communications networks is presented. Although recently accurate deterministic propagation prediction methods have become popular to account for these propagation effects, many mobile operators still employ rather simple and quick semi-deterministic propagation models, which use averaged geo-location information instead of actual building shapes in their calculations. In this work important insights from purely deterministic propagation theories are adopted and employed in a popular semi-deterministic model. After performing measurements, the difference in the prediction error for shadow and no-shadow areas is used to quantify the effect of the blocking object. It is found that statistical geo-location information can be used to predict the amount of blocking in a deterministic way, after application of a simple transformation algorithm. Subsequently, correction factors are proposed in order to adapt the single knife-edge diffraction model to improve the attenuation predictions and prevent the overestimation. The derived factors are based on the degree of urbanity of the environment. Multiplying the predictions of the diffraction model with the environment-based correction factors indeed significantly improves the predictions for the sectors that were studied View full abstract»

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  • Joint TOA/DOA measurements for spatio-temporal characteristics of 2.4 GHz indoor propagation channel

    Page(s): 47 - 50
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (167 KB) |  | HTML iconHTML  

    The aim of this paper is to present a new system based on five-port reflectometers, which measures direction of arrival (DOA) in azimuth plane and propagation time of arrival (TOA) of incoherent signals and coherent signals simultaneously for indoor communication applications. The receiver operating at 2.4 GHz consists of seven five-ports and a uniform linear array (ULA) of seven quasi-Yagi antennas. The spatio-temporal signal processing method is also proposed. Estimation procedure for joint DOA and TOA is based on the multiple signal classification (MUSIC) algorithm associated with spatial smoothing pre-processing (SSP) and the frequency domain sounding technique. It is clear from the simulation results and measurement results that it is possible to measure simultaneously TOA and DOA using five-port technique View full abstract»

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  • Influence of an accurate environment description for the indoor propagation channel modelling

    Page(s): 51 - 54
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (276 KB) |  | HTML iconHTML  

    The current wireless systems evolve towards multimedia applications demanding more and more high bit rate. Consequently, we observe an important rise in frequency. Then, it becomes necessary to study the influence of particular details of environment such as rough surfaces or small and complex scattering structures. Nowadays, ray tracing techniques, based on the geometrical optic (OG) and the uniform theory of diffraction (UTD), are the dominant techniques to predict the channel behaviour over a large bandwidth. Our study aims to improve the ray tracing power for the indoor propagation channel modelling by taking into account particular details of the environment View full abstract»

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  • Direction-of-arrival estimation of highly correlated signals by applying forward-backward averaging to the ESPRIT algorithm for 7-element ESPAR antenna

    Page(s): 55 - 58
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (135 KB) |  | HTML iconHTML  

    The ESPRIT (estimation of signal parameters via rotational invariance techniques) algorithm for the electronically steerable parasitic array radiator (ESPAR) antenna is proposed for the direction-of-arrival (DoA) estimation of highly correlated signals by adding forward-backward averaging (FBA) pre-processing (FBA-ESPAR-ESPRIT). The performance of the proposed method is compared to that of MUSIC and to the Cramer-Rao lower bound (CRB). Results show that FBA-ESPAR-ESPRIT significantly improves the performance of DoA estimation in the case of highly correlated signals and provides a reliability criterion that clearly indicates whether estimates are reliable. Moreover, performance analysis shows that the performance of FBA-ESPAR-ESPRIT is close enough to the CRB to consider it sufficient for DoA finding applications View full abstract»

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  • Investigation of amplitude controlled multi-null-steering smart antenna array

    Page(s): 59 - 62
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (264 KB) |  | HTML iconHTML  

    This paper presents investigation of multi-null-steering antenna array. A new method of nulling is based on controlling signal amplitude in the feeder network, which includes ring hybrid couplers, attenuators and power dividers. A basic concept verified by experiment, concerning single-null-steering antenna array and a simple way to extend this circuit to obtain more degrees of freedom in multi-null steering is shown and analysed View full abstract»

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  • Wideband beam forming with a rectangular array antenna

    Page(s): 63 - 66
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (309 KB) |  | HTML iconHTML  

    This paper presents a wideband beamformer which avoids the use of frequency filters or delay networks to steer a beam in azimuth over a wide frequency band. To achieve an approximately constant radiation pattern with frequency a rectangular, instead of linear, array of wideband planar monopoles is used. The required weighting coefficients, for signals at individual antenna elements, are real numbers which can be realized by attenuators or amplifiers. For an assumed radiation pattern, these weighting coefficients are determined by neglecting mutual coupling effects between the array elements. The effects of mutual coupling are then studied by performing a full EM analysis of the array. It is shown that mutual coupling degrades the side lobe level in the radiation pattern. To overcome this impairment, the method to compensate this adverse effect is described. The compensated weighting coefficients are determined and the radiation patterns are simulated. The modified weighting coefficients are complex numbers. They can be realized in practice by including quadrature hybrid circuits in addition to attenuators or amplifiers already present in the beamformer View full abstract»

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