76 research outputs found

    Acquired constriction ring syndrome as a cause of inconsolable cry in a child: a case report

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    Acute constriction ring syndrome (ACRS) is a rare clinical condition characterized by formation of a circumferential constriction ring around an appendage or genitalia. Cases are mostly reported in infants and young children. Early recognition and a definitive treatment are of paramount importance in order to avoid irreversible ischemia and possible auto-amputation. We describe a case of a 14-month-old child presented to casualty with a history of refusal to feed and inconsolable cry. Parents noticed a recent swelling of left third toe. On careful examination the child was found to have an acquired constriction ring secondary to a tightly wrapped hair around left third toe. An urgent surgical decompression was done by the orthopaedic team with complete resolution of symptoms. We summarized the pathophysiology of ACRS underlining the need of awareness in treating physicians. The possible medico legal implications should be kept in mind bearing a suggested link with non-accidental injury

    Regularized Frequency Domain Equalization Algorithm and its VLSI Implementation

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    Abstract — Approximation of Toeplitz matrices with circulant matrices is a well-known approach to reduce the computational complexity of linear equalizers. This paper presents a novel technique to compute linear equalizer coefficients in the frequency domain. It is shown how a regularization term can help to reduce the error caused by the frequency domain approximation. A corresponding VLSI implementation provides reference for the true silicon complexity and for the complexity increase associated with the proposed algorithm. I

    Regularized frequency domain equalization algorithm and its VLSI implementation

    No full text
    Approximation of Toeplitz matrices with circulant matrices is a well-known approach to reduce the computational complexity of linear equalizers. This paper presents a novel technique to compute linear equalizer coefficients in the frequency domain. It is shown how a regularization term can help to reduce the error caused by the frequency domain approximation. A corresponding VLSI implementation provides reference for the true silicon complexity and for the complexity increase associated with the proposed algorithm

    Performance of MIMO-extended UMTS-FDD downlink comparing space-time RAKE and linear equalizer

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    The paper discusses the performance of a MIMO-extended UMTS-FDD downlink with a 2x2 and a 4x4 antenna configuration. An analytical expression for the average signal to interference ratio (SIR) of a space-time (ST) RAKE receiver in an interference dominated environment is derived. Simulations are used to assess the BER performance with the number of concurrent users as a parameter. The results are compared to a single antenna link with equivalent data rate. In addition to that, a linear zero forcing (ZF) and an MMSE MIMO equalizer receiver is evaluated and compared to the ST-RAKE. It is shown that both methods can successfully mitigate the significant performance Imitation due to self interference (SI) and multiple access interference (MAI)

    A frame-start detector for a 4x4 MIMO-OFDM system

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    Future wireless LANs will increase the peak data rate by employing multiple antennas at both transmitter and receiver

    VLSI implementation of a high-speed iterative sorted MMSE QR decomposition

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    The QR decomposition is an important, but often underestimated prerequisite for pseudo- or non-linear detection methods such as successive interference cancellation or sphere decoding for multiple-input multiple-output (MIMO) systems. The ability of concurrent iterative sorting during the QR decomposition introduces a moderate overall latency, but provides the base for an improved layered stream decoding. This paper describes the architecture and results of the first VLSI implementation of an iterative sorted QR decomposition preprocessor for MIMO receivers. The presented architecture performs MIMO channel preprocessing using Givens rotations in order to compute the minimum mean squared error QR decomposition
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