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    Novel probabilistic bounds on power level profile of spectrally-encoded spread-time CDMA signals [electronic resource]

    , Article IEEE Transactions on Wireless Communications ; Vol. 8, No. 5, PP. 2296-2301, May 2009 Mashhadi, S. (Saeed) ; Sharif University Of Technology
    Abstract
    In this letter we introduce an effective tool to demonstrate signal power behavior of a typical spectrally encoded spread-time (SE/ST) CDMA system using probabilistic approach. By defining power level profile (PLP), as the probability of stretching instantaneous power from a pre-specified threshold, we can find novel upper bounds on the signal power profile. We discuss various properties owing to PLP and elaborate on the main parameters affecting the PLP value. We present three theorems, propose some simple upper bounds on the PLP, and give an insight on the main contributions of the results. We introduce a fundamental parameter, namely ß, as a key design parameter which relates the most... 

    Design and implementation of spectrally-encoded spread-time CDMA transceiver

    , Article IEEE Communications Letters ; Vol. 18, issue. 5 , 2014 , pp. 741-744 ; ISSN: 10897798 Shoreh, M. H ; Hosseinianfar, H ; Akhoundi F ; Yazdian, E ; Farhang, M ; Salehi, J. A ; Sharif University of Technology
    Abstract
    In this paper, we present and discuss the physical implementation and testing of a Spectrally-Encoded Spread-Time Code Devision Multiple Access (SE/ST-CDMA) transceiver. The proposed design is suitable for multiple-access and anti jamming wireless communication systems. The design and implementation takes into account the ability to automatically detect and mitigate tone jammers by altering the corresponding Gold sequence codes assigned uniquely to each user and setting the corresponding code's chip to zero. A simple real-time anti jamming mechanism capable of dealing with frequency hopping jammers is also proposed. The simulation results are provided in terms of Bit Error Rate (BER) versus... 

    Novel probabilistic bounds on power level profile of spectrally-encoded spread-time CDMA signals

    , Article IEEE Transactions on Wireless Communications ; Volume 8, Issue 5 , 2009 , Pages 2296-2301 ; 15361276 (ISSN) Mashhadi, S ; Salehi, J ; Sharif University of Technology
    2009
    Abstract
    In this letter we introduce an effective tool to demonstrate signal power behavior of a typical spectrallyencoded spread-time (SE/ST) CDMA system using probabilistic approach. By denning power level profile (PLP), as the probability of stretching instantaneous power from a pre-specified threshold, we can find novel upper bounds on the signal power profile. We discuss various properties owing to PLP and elaborate on the main parameters affecting the PLP value. We present three theorems, propose some simple upper bounds on the PLP, and give an insight on the main contributions of the results. We introduce a fundamental parameter, namely β, as a key design parameter which relates the most... 

    Detection and Performance Analysis of Spread Time CDMA Systems in the Presence of Multitone Jammers

    , M.Sc. Thesis Sharif University of Technology Akhoondi, Farhad (Author) ; Mashhadi, Saeed (Supervisor)
    Abstract
    In this thesis, we study and analyze the performance of matched and partially-matched re-ceivers for a typical Ultra Wide-band Spectrally-Encoded Spread-Time (SE/ST) CDMA in the presence of multiple tone jammers and a coexisting OFDM system. We investigate a scenario in which there is not any information about the jammer and OFDM subcarrier frequencies in the transmitter side and we try to cancel jammers and interferences at the receiver. For this case, we demonstrate that by using a partially-matched filter at the receiver in an environment with multiple tone jammers and some coexisting systems the performance of the SE/ST system can be improved. We also assume K asynchronous users and... 

    Performance Analysis of Non-Coherent Multi-Level Spectrally-Encoded Spread-Time CDMA over Ultra-Wideband Channel

    , M.Sc. Thesis Sharif University of Technology Hosseinianfar, Hamid (Author) ; Mashhadi, Saeed (Supervisor)
    Abstract
    Nowadays, ultra-wideband (UWB) communication systems are in focus because of their attractive features such as high capacity, low power consumption and robustness against fading. On the other hand, spectrally-encoded spread-time (SE/ST) systems with superior ability on interference suppression provide proper multiuser efficiency over UWB channels. Coherent SE/ST code division multiple access (CDMA) systems are widely addressed in the literature requiring accurate channel estimation and high implementation complexity. In this paper we propose multi-level SE/ST CDMA system with non-coherent detection by considering two different scenarios: i) Known :only channel gain components of desired user... 

    Non-coherent UWB receiver for multi-level spectrally-encoded spread-time CDMA systems

    , Article Proceedings of the International Symposium on Wireless Communication Systems, 28 August 2012 through 31 August 2012 ; August , 2012 , Pages 1069-1073 ; 21540217 (ISSN) ; 9781467307604 (ISBN) Hosseinianfar, H ; Mashhadi, S ; Sharif University of Technology
    2012
    Abstract
    Nowadays, ultra-wideband (UWB) communication systems are in focus because of their attractive features such as high capacity, low power consumption and robustness against fading. On the other hand, spectrally-encoded spread-time (SE/ST) systems with superior ability on interference suppression provide proper multiuser efficiency over UWB channels. Coherent SE/ST code division multiple access (CDMA) systems are widely addressed in the literature requiring accurate channel estimation and high implementation complexity. In this paper we propose multi-level SE/ST CDMA system with non-coherent detection and simple receiver structure. Our results demonstrate the effect of signal to noise ratio...