A. Cidronali

University of Florence, Florens, Tuscany, Italy

Are you A. Cidronali?

Claim your profile

Publications (118)39.41 Total impact

  • Source
    Stefano Maddio · Marco Passafiume · Alessandro Cidronali · gianfranco manes
    [Show abstract] [Hide abstract]
    ABSTRACT: In this paper, we present a distributed positioning system for indoor environment based on a mesh of compact independent anchor nodes. Each node is built of low-cost off-the-shelf components and operates as specialized access points capable of standard connectivity at 2.45 GHz. The key technology for the localization strategy is the switched beam antenna (SBA), which enables a space division multiple access (SDMA) paradigm. The coordinated operation of SBA-equipped anchor nodes constitutes a legacy unmodified IEEE 802.11 network which can exploit the multiplexing mechanism. The latter is the driving force of the estimation strategy, with the positional information obtained as the result of a maximum likelihood algorithm driven by the comparison of a real-time received signal strength indicator (RSSI) with the predicted signal level distribution, which can be estimated and stored without the need of lengthy offline measurement. The signal level prediction is based on a simple propagation model which is effective because benefits of both the elementary antenna radiation beams directivity and the circular polarization operation, two strong aids for the mitigation of the multipath impairment. In turn, these feature make the estimation procedure tolerant to noisy power measurements, hence particularly suitable for cost-effective solutions based on RSSI. Experimental validations demonstrate the performance of a network composed of four anchors arranged in a 2.6 × 3.8 m 2 mesh in a 6 × 7 m 2 office room, and dealing with a single target node. The mean error inside the mesh area is 63 cm while the mean error in the entire room is 1.1 m. Focusing on the cumulative distribution of the error, the 90th percentile value is 1 m considering only the mesh and 1.9 m for the entire room.
    Full-text · Article · Nov 2015 · IEEE Transactions on Microwave Theory and Techniques
  • Source
    stefano maddio · marco passafiume · alessandro cidronali · gianfranco manes
    [Show abstract] [Hide abstract]
    ABSTRACT: In this paper we present a novel Direction of Arrival (DoA) estimator for Switched Beam Antennas (SBA). The proposed approach is based on the best analytic approximation of the power pattern ratio between adjacent beams. Under quite general assumptions, the proposed approach resolves to the solution of a quadratic equation. Compared to conventional estimators, the precision of the proposed approach is competitive, permitting a cost-effective solution for low complexity implementation. Computer simulations and experimental verifications in a anechoic setup confirm the proposed approach when operating with a circular polarized SBA and the received signal strength data collected with a low-cost commercial transceiver. A mean error of 1.1° with a standard deviation of 1.6° is experimentally observed when the SBA communicates with a co-polarized target at the range of 2meters. Only 5% of the observation angle is affected by an error exceeding 5°.
    Full-text · Conference Paper · Sep 2015
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: In this paper we analyze the cancellation of the interference caused by a Intelligent Transportation Systems (ITS) on devices operating in the Dedicated Short Range Communications (DSRC) framework. The cancellation is operated by an interference canceller based on the active feed-forward architecture. The canceller is designed to operate over the frequency band 5.2 GHz - 6.4 GHz, hence it is suitable for the mitigation of mutual interference on signal pertinent to DSRC at 5.8GHz due to ITS signals at 5.9 GHz. When applied to a Road Side Unit (RSU) for electronic toll collection (ETC) operating at 5.8 GHz, the proposed technique is capable to improve the performance of the front-end by cancelling the interfering signal in the 5.9 GHz bandwidth such as IEEE 802.11p signals involved in the ITS protocols; signal-to-interference improvement of 25 dB operating on 10MHz bandwidth signal is herein reported. The paper introduces the architecture of the canceller as well as the experimental results which describe the capability of the technical approach.
    Full-text · Article · Jun 2015
  • Source
    S. Maddio · M. Passafiume · A. Cidronali · G. Manes
    [Show abstract] [Hide abstract]
    ABSTRACT: In this paper we present a distributed positioning system for indoor environments based on a network of compact independent anchor nodes operating as specialized WiFi access points. Each node is built with component-off-the-shelves and it is capable of standard IEEE 802.11 connectivity at 2.45 GHz. The enabling technology for the localization is the Switched Beam Antenna (SBA) equipped in each node, which permits a space division multiple access at network-level.
    Full-text · Conference Paper · May 2015
  • Alessandro Cidronali · Stefano Maddio · Giovanni Collodi · Gianfranco Manes
    [Show abstract] [Hide abstract]
    ABSTRACT: This letter introduces a method for the optimum design of a compact transponder front-end for dedicated short range communication (DSRC) operating at 5.8 GHz band and suitable for electronic toll collection (ETC) vehicular applications. The DSRC transponder front-end is based on a circularly polarized antenna and a RF diode, which provides both the functionalities of envelope detector and back-scatterer. The design method is based on the characterization and optimization of the frequency conversion mechanism occurring in the front-end during up and downlink while the best trade-off between design parameters are identified on the base of sensitivity and back-scatterer gain. These parameters optimize the DSRC transponder front-end in the two links and thus leads to the maximum operative range. The methods are validated through the design of three prototypes responding to different design constraints and tested in the context of a realistic scenario of DSRC for ETC according to the ETSI EN300674 communication layers. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1187–1191, 2015
    No preview · Article · May 2015 · Microwave and Optical Technology Letters
  • Stefano Maddio · Alessandro Cidronali · Gianfranco Manes
    [Show abstract] [Hide abstract]
    ABSTRACT: This paper describes the design principles for a real-time adaptive transmitter leakage canceller and introduces its training algorithm for fast adaptation. The canceller implements the active feed-forward analog cancelling technique, which considers the injection at the receiving input of the self-interfering antiphase signal. An extensive characterization carried out on a prototype designed to operate at the center frequency of 5.8 GHz demonstrates the performance of the prototype in term of cancellation and tracking convergence speed, and confirms the validity of the canceller design principles. Measurements at 5.8 GHz show that for isolation between the transmitting and receiving antenna up to 35 dB with arbitrary phase, an isolation above 60 dB is obtained in 98.5% of the tests and this result is reached in six steps. When applied to a wireless transceiver for electronic-toll collection system operating in full duplex at 5.8 GHz under regulation European Telecommunications Standards Institute ES200674, the prototype permits a signal-to-noise-ratio enhancement of 8.3 dB.
    No preview · Article · Feb 2015 · IEEE Transactions on Microwave Theory and Techniques
  • Source
    Marco Passafiume · Stefano Maddio · Alessandro Cidronali · Gianfranco Manes
    [Show abstract] [Hide abstract]
    ABSTRACT: Existing global positioning systems (GPS) applications are normally denied in indoor environments where, in spite of this limitation, a number of interesting applications are evolving into commercial products. At presently for indoor positioning, there are few cost-effective alternatives to GPS. One promising approach is based on the received signal strength indicator (RSSI) estimation, which is available into every IEEE standard compliant wireless transceiver, and includes useful information about mutual positions between two position reference nodes. Extrapolating distance evaluation from RSSI is not reliable unless the adoption of accurate channel model. By using an anchor node/router with an array of directive antennas it is possible to implement the spatial subdivision aimed at achieving an estimation of the direction of arrival (DoA) evaluating ratios between single anchor's antennas, and thus independently from channel characteristics. This approach makes use of spectral-based DoA localization algorithms already existing, but all of them assume real-time analysis of both amplitude and phase of received signals. In this article we demonstrate analytically the capability of the MUSIC algorithm (\cite{algMusic}) to elaborate only the RSSI readings. In the paper we also discuss a comparison between DoA localization performance using the classical information set (i.e. amplitude and phase) versus the use of the RSSI set (obtained simply reading transceiver standard registers). In conclusion we introduce some fundamental array design principles for optimal MUSIC RSSI implementation, with a real implementation tracking test.
    Full-text · Article · Jan 2015 · WSEAS Transactions on Signal Processing
  • Alessandro Cidronali · Stefano Maddio · Giovanni Collodi · Gianfranco Manes
    [Show abstract] [Hide abstract]
    ABSTRACT: This paper discusses the system level analysis of Envelope Tracking (ET) power amplifier (PA) applied to FDD transceivers by X-parameter model. In particular, efficiency and linearity of the transmitter are analyzed. Additionally is analyzed the receiver desensitization issue, due to the interaction with the transmitter. The system-level analysis led to the possible tradeoffs between the several system parameters, the implementation constraints and the system performance, as well as the most critical aspects for the effective development of ET-PA capable to deal with wide bandwidth signal.
    No preview · Article · Dec 2014
  • A. Cidronali · S. Maddio · G. Collodi · G. Manes
    [Show abstract] [Hide abstract]
    ABSTRACT: This paper discusses the system level analysis of Envelope Tracking (ET) power amplifier (PA) applied to FDD transceivers by X-parameter model. In particular, efficiency and linearity of the transmitter are analyzed. Additionally is analyzed the receiver desensitization issue, due to the interaction with the transmitter. The system-level analysis led to the possible trade-offs between the several system parameters, the implementation constraints and the system performance, as well as the most critical aspects for the effective development of ET-PA capable to deal with wide bandwidth signal.
    No preview · Article · Dec 2014
  • Source
    Stefano Maddio · Marco Passafiume · Alessandro Cidronali · Gianfranco Manes
    [Show abstract] [Hide abstract]
    ABSTRACT: This paper presents an investigation about Switched Beam Antennas (SBA) for indoor positioning systems based on RSSI measurements. Given practical consideration on hardware costs, the device in exam is based on low-cost commercial components capable of standard WiFi connectivity at 2.45 GHz. The SBA is the enabling technology for Beam Diversity Multiple Access of smart WiFi nodes. Upon the reception of radio messages from generic mobile devices, the node estimates the DoA of the incoming signals on the basis of a likelihood criterion driven by the expcedted beam diversity. SBA design has great impact on the localization performance. In this paper an investigation around the SBA shape is presented, with particular emphasis on the effects of the dihedral angle of regular polyhedron-type SBA. Thanks to a model based on trustful electromagnetic simulations, some conclusions on the general design principles of the SBA's are drawn.
    Full-text · Conference Paper · Dec 2014
  • Source
    Marco Passafiume · Stefano Maddio · Alessandro Cidronali · Gianfranco Manes
    [Show abstract] [Hide abstract]
    ABSTRACT: In last years the interest in indoor localization techniques is grown very quickly: due to huge increase of interest in domotic technologies and to fast improvement of capabilities for mobile devices, which are becoming always-connected support points for standard users, the capability of making spatial data-contextualization has become an important point of interest. Existing GPS technologies aren't capable of realizing sufficient accuracy needed for indoor positioning, so it is necessary to find alternative cost-effective methods to resolve localization problem. Excluding odometry-based tracking methods (which present a lot of uncertainty for making an absolute positioning), famous signal DoA (Direction Of Arrival) spectral-based localization algorithms like CAPON, ESPRIT, MUSIC[1],[2] provide valid localization accuracy assuming device capability to analyze in real-time physical parameters (amplitude/phase) of received radiocommunication signals to a spatial antenna array. This requirement could be achieved using ad-hoc radio equipment, which causes an increase of production costs: maybe, it is far better to develop some kind of new algorithms capable of using standard IEEE wireless protocols information (like RSS indicator, RSSI) for positioning elaboration. In this article, it will be analytically demonstrated the capability of MUSIC[1] algorithm to elaborate RSSI standard transceiver values (placing some measurement conditions), and there will be shown a comparison between DoA localizations using the classical information set (amplitude/phase) and the RSSI set (obtained simply reading transceiver standard registers).
    Full-text · Conference Paper · Nov 2014
  • Stefano Maddio · Alessandro Cidronali · Gianfranco Manes
    [Show abstract] [Hide abstract]
    ABSTRACT: This paper proposes a new design for dual-band Circularly Polarized (CP) microstrip antennas. CP antennas are advantageous for indoor communications due to their intrinsic robustness to multipath. In addition, Dual-band operation is another aid for communication in the sense of reconfigurability issue. The proposed antenna is a disc patch loaded by 2 pairs of parasitic crown segments, printed on common dielectric substrate and fed by a coaxial probe. With this design, dual band configurations with small frequency ratio - from 4% to 16% - can be flexibly designed, without sacrificing the gain. By the means of a parametric characterization, which serves either as a guideline, and as the staring point for an extensive optimization, the cases ranging from 2.45/2.55 to 2.45/2.85 GHz are investigated. The validation of this approach is proven by designing and fabricating a set of prototypes implemented with common low-cost FR4 dielectric substrate. A mean Left Hand CP Gain of 4dB is measured at first operation peak, while a mean of 2.25 dB is found for the second peak for all the fabricated configurations. All the peak resonances shows at least 15 dB of polarization ratio, confirming the validity of the proposed design.
    No preview · Conference Paper · Oct 2014
  • [Show abstract] [Hide abstract]
    ABSTRACT: We discuss the development of a wideband LDMOS Doherty PA (DPA) with optimized peak power and efficiency over 550 MHz to 770 MHz of bandwidth. The design was enabled by a wideband output combiner which involves multisection impedance transformation. The DPA delivers more than 46% average efficiency across the band at 48 dBm average power supporting DVB-T signal with 8 MHz bandwidth and PAPR of 10.5 dB. The DPA prototype achieves the target ACPR of - 50 dBc at the upper limit of the bandwidth if digital predistortion is applied.
    No preview · Conference Paper · Jun 2014
  • Alessandro Cidronali · Stefano Maddio · Giovanni Collodi · Gianfranco Manes
    [Show abstract] [Hide abstract]
    ABSTRACT: This paper analyses the issue of receiver desensitization, due to the interaction with the transmitter in Envelope Tracking (ET) based FDD transceivers. The purpose of the study is to assess the possible trade-offs between the several system parameters, the implementation constraints and the system performance. The data reported in the paper consider an accurate model of the ET-PA obtained by a previous research, and a combination of data-flow and envelope simulations. The test signal adopted as case study is a legacy LTE10 for up-link user equipments. The paper shows that a best trade-off between the DAC ENOB in the envelope modulation path, and the shaping function discretization, consists respectively in 9 bit and 2^6 byte.
    No preview · Conference Paper · Feb 2014
  • [Show abstract] [Hide abstract]
    ABSTRACT: This paper presents the design of a high-power dual-band power amplifier (PA) for envelope tracking (ET) operation and its characterization in concurrent dual-band ET operation modes. The design approach relies on the specific actual signal probability distribution and the prototype was conceived for the WCDMA 3GPP DL signals. The paper discusses the impact of the ET-shaping function influence on the linearity versus mean efficiency trade-off, for both single and concurrent dual-band cases. The technique was applied to a concurrent 870 and 2140 MHz ET-PA designed around a GaN HEMT device. The ET friendly design method led to performance very close to those observed at each single band. Over a bandwidth of 100 MHz and for PAR = 6.5 dB, the measured results reported a mean DE better than 71 and 54%, with a peak power higher than 55 and 54 dBm, at the two frequency bands, respectively. When evaluated in concurrent dual-band mode with two WDCMA signals at 6.5 dB PAR each, the ET-PA exhibited an estimated average total power of 49.5 dBm with 57.1% average drain efficiency.
    No preview · Article · Dec 2013 · International Journal of Microwave and Wireless Technologies
  • Source
    Stefano Maddio · Marco Passafiume · Alessandro Cidronali · Gianfranco Manes
    [Show abstract] [Hide abstract]
    ABSTRACT: This paper presents a distributed localization system for indoor environment based on a network of compact anchor nodes. The system is based on available low-cost commercial components and it is capable of standard WiFi connectivity at 2.45 GHz. The basic node is equipped with a switch-beam antenna, which is the enabling technology for a Direction of Arrival (DoA) estimation based on Maximum-Likelihood criteria. The adopted DoA estimation procedure is tolerant to noisy power measurements, making it suitable for low-cost effective solutions based on RSSI measurements. The node is designed to be placed in an unobtrusive area for the movement of a mobile target node and is capable to operating as an independent anchor, but it is optimized to cooperate with other identical nodes to form a coordinated network of anchors, capable to monitor an extended indoor area. An experimental characterization demonstrates the DoA performance of the single node.
    Full-text · Conference Paper · Oct 2013
  • [Show abstract] [Hide abstract]
    ABSTRACT: This letter presents a signal probability distribution function conscious characterization technique, suitable for the optimization of envelope tracking (ET) power amplifiers. The method and its validation rely on pulsed harmonic load-pull measurements. The analytical treatment permitted to understand the impact of the peak-to-average power ratio on the load termination, and the experimental characterization revealed the sensitivity of the ET performance with respect to the load termination. The technique was applied to a GaN HEMT device at the carrier frequency of 870 MHz.
    No preview · Article · Jul 2013 · IEEE Microwave and Wireless Components Letters
  • G. Casini · A. Cidronali · G. Manes
    [Show abstract] [Hide abstract]
    ABSTRACT: This work reports the experimental evaluation of X-parameters models for the simulation of ET systems. We have extracted 2-port and 3-port X-parameters models from large signal vector measurements, for a GaAs PA with 40 dBm nominal peak power at 850 MHz. The data suggests that 3-port X-parameter model not only leads to an accuracy improvement during the estimation of average DE and ACLR but also permits the extraction of constant gain shaping functions that increase the overall system linearity.
    No preview · Conference Paper · Jun 2013
  • Stefano Maddio · Alessandro Cidronali · Alessandro Palonghi · Gianfranco Manes
    [Show abstract] [Hide abstract]
    ABSTRACT: This paper details the implementation and performance of an reconfigurable carrier leakage canceler for 5.8 GHz Dedicated Short-Range Communications. DSRC systems suffer of desensibilization because of large leakage of the carrier due to imperfect TX-RX antenna isolation. The proposed circuit, which consists of electrically tunable attenuator and a phase shifter, can be adaptively tuned to erase the leaked signal. Hardware realization is carried out based on simulation model in ADS (Advanced Design System). Measurement results indicate that the TX-to-RX isolation is improved from 35 dB to above 58 dB at center frequency, or an improvement of more than 23 dB of carrier leakage cancellation. To the author knowledge it is an unmatched result at the frequency of 5.8 GHz.
    No preview · Conference Paper · Jun 2013
  • Stefano Maddio · Alessandro Cidronali · Stefano Maurri · Gianfranco Manes
    [Show abstract] [Hide abstract]
    ABSTRACT: This paper details the implementation and performance of a new compact 5.8 GHz Transponder for Dedicated Short-Range Communication (DSRC). The core of the system is a low power RFIC composed of an amplifier and supeheterodyne converter, while the radiative system consists of an original low profile planar antennas operating in Left Hand Circularly Polarization (LHCP) for both Tx/Rx channel. The planar antenna technology offer the benefits of low-cost, ease of manufacture and low-profile, but it requires accurate and time-consuming tunings to reach optimal radiation and matching condition. The performance of the proposed DSRC transponder are boosted by efficient design for both Tx and Rx antennas which is based on a evolution of the original solution proposed by the authors. Measured results of a fabricated prototype show a wide and regular angular response and a net gain exceeding 15 dB in the linear range of function.
    No preview · Article · May 2012