Institute for Systems Research Technical Reports

Permanent URI for this collectionhttp://hdl.handle.net/1903/4376

This archive contains a collection of reports generated by the faculty and students of the Institute for Systems Research (ISR), a permanent, interdisciplinary research unit in the A. James Clark School of Engineering at the University of Maryland. ISR-based projects are conducted through partnerships with industry and government, bringing together faculty and students from multiple academic departments and colleges across the university.

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Author: search.filters.author.Baras, John S.Subject: search.filters.subject.ASIC supporting multiple modulation

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    Dynamic ElGamal Public Key Generation with Tight Binding
    (1999) Poovendran, R.; Corson, M. Scott; Baras, John S.; ISR; CSHCN
    We present a new distributed, group ElGamal public key generation algorithm which also permits maintenance of a group-specific, dynamic,individual ElGamal public key infrastructure.

    We parameterize the group with a time-varying quantity that servesas a distributed mechanism for controlling key generation privilege.

    Our scheme can be viewed as an alternative to polynomial schemes where, at the time of the secret construction step, there has to be a third party or a black box to combine the shares. Also, in polynomial schemes, at the time of combining, the individual shares of the secret have to be revealed to the third party. In our scheme, the common secret can be generated without ever exposing the individual shares constructing it.

    We note that many of the recently proposed distributed key management~[2-4] schemes need such group keys for certification and signing purposes.

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    VLSI Implemented ML Joint Carrier Phase and Timing Offsets Joint Estimator for QPSK/QQPSK Burst Modems
    (1999) Jiang, Yimin; Verahrami, F.B.; Richmond, R.L.; Baras, John S.; Baras, John S.; ISR; CSHCN
    A high performance ASIC supporting multiple modulation, error correction, and frame formats is under development at Hughes Network Systems, Inc. Powerful and generic data-aided (DA) estimators are needed to accommodate operation in the required modes. In this paper, a simplified DA maximum likelihood (ML) joint estimator for carrier phase and symbol timing offset for QPSK/OQPSK burst modems and a sample systolic VLSI implementation for the estimator are presented.

    Furthermore, the Cramer-Rao lower bound (CRLB) for DA case is investigated. The performance of the estimator is shown through simulation to meet the CRLB even at low signal-to-noise ratios (SNR). Compared with theoretical solutions, the proposed estimator is less computationally intensive and is therefore easier to implement using current VLSI technology. IEEE Wireless Communications and Networking Conference: WCNC'99