The Experts below are selected from a list of 84 Experts worldwide ranked by ideXlab platform

Milunka Damnjanović - One of the best experts on this subject based on the ideXlab platform.

Borisav Jovanovic - One of the best experts on this subject based on the ideXlab platform.

Behrouz Farhangboroujeny - One of the best experts on this subject based on the ideXlab platform.

  • analysis of discrete time mimo ofdm based orthogonal time frequency space modulation
    International Conference on Communications, 2018
    Co-Authors: Ahmad Rezazadehreyhani, Arman Farhang, Rongrong Chen, Behrouz Farhangboroujeny
    Abstract:

    Orthogonal Time Frequency Space (OTFS) is a novel modulation scheme designed in the Doppler-delay domain to fully exploit time and frequency diversity of general time-varying channels. In this paper, we present a novel discrete-time analysis of OFDM-based OTFS transceiver with a concise and vectorized input-output relationship that clearly characterizes the contribution of each underlying Signal Processing Block in such systems. When adopting cyclic prefix in the time domain, our analysis reveals that the proposed MIMO OTFS and OFDM systems have the same ergodic capacity despite the well-known fact that the former has great advantages in low-complexity receiver design for high Doppler channels. The proposed discrete-time vectorized formulation is applicable to general fast fading channels with arbitrary window functions. It also enables practical low-complexity receiver design for which such a concise formulation of the input-output relationship is of great benefits.

  • multicarrier modulation with blind detection capability using cosine modulated filter banks
    IEEE Transactions on Communications, 2003
    Co-Authors: Behrouz Farhangboroujeny
    Abstract:

    The cosine modulated filter bank (CMFB) is introduced as a multicarrier modulation (MCM) technique for wideband data transmission over wireless channels. Under the name discrete wavelet multitone modulation, CMFB has been considered for data transmission over digital subscriber lines. We propose a new receiver structure that is different from those proposed previously. The new structure simplifies the task of channel equalization, by reducing the number of equalizer parameters significantly. We also propose a novel blind equalization algorithm that fits very nicely in the proposed structure. Moreover, we discuss the bandwidth efficiency of the proposed CMFB-MCM system and show that it is superior to the conventional (single carrier) quadrature amplitude modulation (QAM) and orthogonal frequency-division multiplexing (OFDM). The CMFB is found to be a Signal Processing Block that stacks a number of vestigial sideband modulated Signals in a number of overlapping subchannels in the most efficient way. The proposed CMFB-MCM is also compared to OFDM with respect to bit-error rate performance. Under the conditions that the channel impulse response duration remains less than the length of cyclic prefix, OFDM is found marginally superior to CMFB-MCM. However, OFDM degrades very fast when the channel impulse response duration exceeds the length of the cyclic prefix. CMFB-MCM, on the other hand, is found less sensitive to variations in channel impulse response duration.

Arto Kaarna - One of the best experts on this subject based on the ideXlab platform.

  • Rain Clutter Filtering from Radar Data with Discrete Wavelet Transform
    2006 International Radar Symposium, 2006
    Co-Authors: Ilkka Ellonen, Arto Kaarna
    Abstract:

    Moving weather systems will have a nonzero Doppler response at rate at which the rain droplets are approaching the radar system. The complete data the radar collects contain the returns of both the target and the clutter. The Signal Processing Block in a radar system uses filtering operations to extract the target information while suppressing the clutter. Typically the filters are designed based on Doppler Frequency using a Fourier filter bank. Instead of the frequency domain, the wavelet analysis allows the time-scale domain in Processing. The filter bank in this study utilizes Discrete Wavelet Transform (DWT), DWT coefficients represent the results of a multi-resolution analysis of the radar Signal. We study the operation of a DWT filter bank and a Fourier filter bank (FFT). Our experiments indicate that the Fourier filter bank filter the rain clutter very well. However, a DWT filter bank has different time resolution for different frequency ranges. With very heavy rain clutter affecting to the target signatures, our experiments indicate that the wavelet filter bank performs better than the Fourier filter bank. The experiments were performed in MATLAB environment and data is real radar rain clutter data from Finnish Air Force medium range air surveillance radar (low PRF). The objectives of this study were to develop a DWT based filtering system and to test it's operation in one situation of rain clutter and then to compare it's results to those from the FFT method.

  • Rain Clutter Filtering from Radar Data with Slope Based Filter
    2006 European Radar Conference, 2006
    Co-Authors: Ilkka Ellonen, Arto Kaarna
    Abstract:

    One type of volume clutters is rain clutter that is caused by rain droplets. Moving weather systems will have a nonzero Doppler response the rate at which the rain droplets approach to the radar system. The complete data radar collects contain the returns of both the target and the clutter. The Signal Processing Block in a radar system uses filtering operations to extract the target information while suppressing the clutter. Typically the filters are designed based on Doppler frequency using a Fourier filter bank. In this paper, we study the slope based filtering algorithm, and present some results obtained using that filter. Our experiment is indicating two interesting results. Firstly, the slope based filtering algorithm filter rain clutter at least as well as the Fourier filter bank. Secondly, the slope based filter performed better than the Fourier filter bank in the case of the generated Gaussian white noise. The experiments were performed in MATLAB environment and the data was real radar rain clutter data from Finnish Air Force medium range air surveillance radar (low PRF). Fifty different rain and snow situations have been recorded into data

Claude Cadoz - One of the best experts on this subject based on the ideXlab platform.

  • Interfacing Digital Waveguide with CORDIS ANIMA networks
    Journal of the Acoustical Society of America, 2008
    Co-Authors: Alexandros Kontogeorgakopoulos, Claude Cadoz
    Abstract:

    The aim of this article is mainly to offer a link between the Digital Waveguide and the CORDIS-ANIMA physical modeling formalism. The first one is highly a modular lumped physical modeling and simulation system based on the mass-interaction paradigm while the second one offers accurate and efficient discrete time distributed models synthesized typically by delay lines and scattering junctions, in combination with digital filters. Both of them are widely developed and used in the domain of computer music field by scientists and artists. Although Digital Waveguide models have already been combined with Wave Digital Filters, they have never been exploited and integrated with CORDIS ANIMA networks. Wave Digital Filters are lumped models which are based on a scattering theoretic formulation which simplifies interfacing to Digital Waveguide models in contrast with the CORDIS ANIMA models. This research investigates the similarities of those formalisms, as well as focuses on the advantages of each modeling technique and proposes a real time computable interface between them. Moreover it results as well in a common convenient structural representation of their computational algorithms using Signal Processing Block diagrams. These hybrid models were designed directly by their Block diagrams, simulated and run in differ time using the Simulink software package of the matlab technical computing language.

  • Cordis Anima Physical Modeling and Simulation System Analysis
    2007
    Co-Authors: Alexandros Kontogeorgakopoulos, Claude Cadoz
    Abstract:

    The CORDIS-ANIMA physical modeling system is one of the oldest techniques for digital sound synthesis via physical modeling. This formalism which is based on the mass-interaction paradigm has been designed and developed by ACROE in several stages since 1978. The aim of this article is to enlighten some special and particulars features of this approach by exploiting it mathematically. Linear CORDIS-ANIMA (CA) models are studied and presented using several useful system representations like system function input/output external descriptions, state space internal descriptions, finite difference model, modal decomposition, electrical analogous circuits, CA networks and digital Signal Processing Block diagrams.