Ivana Raos

Cattle-Powered Node Experience in a Heterogeneous Network for Localization of Herds

A heterogeneous network, mainly based on nodes that use harvested energy to self-energize, is presented, and its use is demonstrated. The network, mostly kinetically powered, has been used for the localization of herds in grazing areas under extreme climate conditions. The network consists of secondary and primary nodes. The former, powered by a kinetic generator, take advantage of animal movements to broadcast a unique identifier. The latter are battery-powered and gather secondary-node-transmitted information to provide it, along with position and time data, to a final base station in charge of the animal monitoring. Because a limited human interaction is desirable, the aim of this network is to reduce the battery count of the system.

Transmission techniques for downlink multi-antenna MC-CDMA systems in a beyond-3G context

The combination of multiple antennas and multi-carrier code division multiple-access (MC-CDMA) is a strong candidate for the downlink of the next generation mobile communications. The study of such systems in scenarios that model real-life transmissions is an additional step towards an optimized achievement. We consider a realistic MIMO channel with two or four transmit antennas and up to two receive antennas, and channel state information (CSI) mismatches. Depending on the mobile terminal (MT) class, its number of antennas or complexity allowed, different data-rates are proposed with turbo-coding and asymptotic spectral efficiencies from 1 to 4.5 bit/s/Hz, using three algorithms developed within the European IST-MATRICE project. These algorithms can be classified according to the degree of CSI at base-station (BS): i) Transmit space-frequency prefiltering based on constrained zero-forcing algorithm with complete CSI at BS; ii) transmit beamforming based on spatial correlation matrix estimation from partial CSI at BS; iii) orthogonal space-time block coding based on Alamouti scheme without CSI at BS. All presented schemes require a reasonable complexity at MT, and are compatible with a single-antenna receiver. A choice between these algorithms is proposed in order to significantly improve the performance of MC-CDMA and to cover the different environments considered for the next generation cellular systems. For beyond-3G, we propose prefiltering for indoor and pedestrian microcell environments, beamforming for suburban macrocells including highspeed train, and space-time coding for urban conditions with moderate to high speeds.

A Heterogeneous Wireless Identification Network for the Localization of Animals Based on Stochastic Movements

The improvement in the transmission range in wireless applications without the use of batteries remains a significant challenge in identification applications. In this paper, we describe a heterogeneous wireless identification network mostly powered by kinetic energy, which allows the localization of animals in open environments. The system relies on radio communications and a global positioning system. It is made up of primary and secondary nodes. Secondary nodes are kinetic-powered and take advantage of animal movements to activate the node and transmit a specific identifier, reducing the number of batteries of the system. Primary nodes are battery-powered and gather secondary-node transmitted information to provide it, along with position and time data, to a final base station in charge of the animal monitoring. The system allows tracking based on contextual information obtained from statistical data.

Improvement of multiple antennas diversity systems through receiver nonlinear coupling cancellation

In order to gain diversity and achieve high bit rates, the recent trends in mobile communication industry include the use of multiple antennas in transmitter and at the receiver. As the mobile terminals get smaller, the number of electronic elements inside of them rises and the electronic interferences, like RF coupling, emerge. In this contribution, the coupling is modeled with polynomials limited to third order nonlinear behavior. To combat the multi antenna RF front-end coupling the software module at the output of AD converter is proposed. Inside the module, signal enhancement is achieved based on the inverse nonlinear coupling function of the 9th degree. The inverse function is solved using simulated annealing (SA) approximation method. The proposed coupling cancellation algorithm is analyzed under different system conditions showing excellent coupling cancellation characteristics.

Validation of a HF spread spectrum multi-carrier technology through real-link measurements

SUMMARYThe HF band data communication link has been traditionally desired by many of the large rangetransmission systemsalthough it is associated tounfavourable performancesas low transmission rate, largedelayandlowconfidenceintermsoflinkestablishmentandmaintenance.Althoughtransmissionrates maybe highenough totransmit digitalvoice, delay,usuallyover severalseconds, has beenthe mainhandicap tolet the systems provide interactive digital voice links. Indeed, there is no unclassified equipment with thiscapability.Themainachievementofthisproposalisthatweareabletoguaranteedigitalvoicetransmissionwith low latency, around 135ms (modemþcodec), providing a full interactive digital voice link.Performances of two new 2460bps HF modems are presented versus the 39-tone 2400bps MIL-STD-188-110A modem, working over an ITU-R moderate channel. Furthermore, these results are corroborated byreal tests carried out in a 1800Km link in the 18MHz band. Copyright # 2006 AEIT. 1. INTRODUCTION1.1. The HF channelIn the HF band (3–30MHz), long distance communica-tions are feasible, thanks to the use of the ionosphere aspassive reflector. However, the atmospheric nature of thisreflector makes the systems face a very hard communica-tionenvironment.Multipatheffects arealways present andhave to be considered in depth, besides the very fast time-varying channel characteristics.The main parameters used to measure channel behaviourare frequencycoherence ( f

Efficient RF Front-End Non-Linear Multi Antenna Coupling Cancellation Techniques

One of the recent trends in mobile communication industry is the use of multiple antennas in transmitter and at the receiver in order to gain diversity and achieve high bit rates. At the same time, as the mobile terminals are getting smaller, the number of electronic elements squeezed inside of them increases. Inside this hostile environment the coupling, which can considerably alter the overall system performance, is bound to emerge. To combat the multi antenna RF front-end coupling a DSP software module, positioned between the output of AD converter and any further digital signal processing is proposed. The coupling is modelled with polynomials limited to third order nonlinear behaviour. The inverse nonlinear coupling function of the 9th degree is solved using simulated annealing (SA) approximation method. The proposed coupling cancellation algorithm is analyzed under different system conditions with different processing power requirements. A trade off between the guaranteed precision and speed is made, and the simplified algorithm version, showing good coupling cancellation characteristics, is presented.

Real-link Performance of a SS-MC-MA High Frequency Radio Modem

The HF band data communication link has been traditionally desired by many of the large range transmission systems although it is associated to unfavorable performances as low transmission rate, large delay and low confidence in terms of link establishment and maintenance. Although transmission rates may be high enough to transmit digital voice, delay, usually over several second, has been the main handicap to let the systems provide interactive digital voice links. Indeed, there is no unclassified equipment with this capability. The main achievement of this proposal is that we are able to guarantee digital voice transmission with low latency, around 135 msec (modem+codec), providing a full interactive digital voice link. Performances of two new 2460 bps. HF modems are presented versus the 39-tone 2400 bps MIL-STD-188-110A modem, working over an ITU-R moderate channel. Futhermore, these results are corroborated by real tests carried out in a 1800 Km. link.

Advanced receivers for MC-CDMA with modified digital prolate functions

Modified digital prolate functions (DPF) are addressed in this paper, applied as waveforms for downlink MC-CDMA systems and providing higher transmission rates. Those waveforms, thanks to their double orthogonality and energy concentration in restricted interval properties, enable specific processing at the receiver. Design and analysis of advanced receivers exploiting the abovementioned DPF properties and computer simulations that demonstrate their performance improvement compared to MC-CDMA system with Hadamard codes are presented.

Rectangular room dimensions estimation using narrowband signal and sectorized antennas

A system for estimation of unknown rectangular room dimensions based on two radio transceivers, both capable of full duplex operations, is presented. The approach is based on CIR measurements taken at the same place where the signal is transmitted (generated), commonly known as self-to-self CIR. Another novelty is the receiver antenna design which consists of eight sectorized antennas with 45° aperture in the horizontal plane, whose total coverage corresponds to the isotropic one. The dimensions of a rectangular room are reconstructed directly from radio impulse responses by extracting the information regarding features like round trip time, received signal strength and reverberation time. Using radar approach the estimation of walls and corners positions are derived. Additionally, the analysis of the absorption coefficient of the test environment is conducted and a typical coefficient for office room with furniture is proposed. Its accuracy is confirmed through the results of volume estimation. Tests using measured data were performed, and the simulation results confirm the feasibility of the approach.

Generic SDR Platform Used for Multi-Carrier Aided Localization

This paper describes the Software Defined Radio (SDR) platform that is being developed and implemented in the scope of the EU seventh Framework WHERE Project. The platform is based on one full-length PCI carrier board populated with one DSP module, one dual high-speed ADC/DAC module and one module corresponding to IF/RF front-end. It is equipped with two omni-directional antennas working at 2.4 GHz with 100 MHz bandwidth. The platform is not restrained only to the PC tower box since its mobility is guaranteed with small portable PCI bus extension chassis supporting PCMCIA laptop connections. It is intended for exploring the localization possibilities of different multi-carrier interfaces.