The European Conference on Wireless Technology, 2005.

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 hig... View full abstract»

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... View full abstract»

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 su... View full abstract»

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 dB... View full abstract»

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... View full abstract»

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 vol... View full abstract»

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 ... View full abstract»

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, ... View full abstract»

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 profil... View full abstract»

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, w... View full abstract»

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 antenn... View full abstract»

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 unif... View full abstract»

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 a... View full abstract»

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-nu... View full abstract»

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 numbe... View full abstract»