Efficient implementation of linear multiuser detectors

Wang, X.F.; Lu, Wu-Sheng; Antoniou, A.

doi:10.1109/icassp.1998.679550

Cited by 6 publications

(2 citation statements)

References 11 publications

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“…Consequently, recursive relations similar to those in (10a)-(c) hold for , , and the corresponding blocks in . Using these recursive formulas, efficient algorithms for updating the Cholesky factors and user detection can be found [10].…”

Section: A Owd Detectormentioning

confidence: 99%

An overlapping window decorrelating multiuser detector for DS-CDMA radio channels

Wang

Antoniou

2001

IEEE Trans. Commun.

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Abstract-A new multiuser detector for direct-sequence codedivision multiple-access communication systems is described. The proposed detector divides the received signal stream into a number of overlapping windows and decorrelates them window by window. This scheme is justified by an analysis on the convergence and decay rate of the impulse response. Based on the results, a signaladapted criterion is developed which enables one to determine the window length according to the near-far situation of a practical system. A performance analysis and simulation results show that a small to moderate window length is usually sufficient to yield a performance that is close to or even better than that of the ideal decorrelating detector.

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Section: A Owd Detectormentioning

confidence: 99%

An overlapping window decorrelating multiuser detector for DS-CDMA radio channels

Wang

Antoniou

2001

IEEE Trans. Commun.

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“…For asynchronous systems, a window approach is usually adopted that results in a symbol-by-symbol detection [8], [9]. As an alternative, each symbol within the observation window, which usually spans an odd number of symbol intervals [8], can be deemed to originate from a different synchronous user. By doing this, an asynchronous system can be interpreted as an equivalent synchronous system [2].…”

Section: Preliminariesmentioning

confidence: 99%

Constrained minimum-BER multiuser detection

Wang

Antomiou³

2000

IEEE Trans. Signal Process.

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A new linear multiuser detector that directly minimizes the bit-error rate (BER) subject to a set of reasonable constraints is proposed. It is shown that the constrained BER cost function has a unique global minimum. This allows us to develop an efficient barrier Newton method for finding the coefficients of the proposed detector using information about timing, amplitudes, channels, and the signature signals of all users. Although the new detector cannot be shown to be optimal among linear multiuser detectors without the constraints imposed, extensive simulations demonstrate that it achieves the lowest BER. Furthermore, in some cases, the BER of the proposed detector can be significantly lower than that of the decorrelating and MMSE detectors. Index Terms-Bit-error rate minimization, interior-point numerical optimization, multiuser detection.

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Hiding digital watermarks using multiresolution wavelet transform

Hsieh

Tseng

Huang

2001

IEEE Trans. Ind. Electron.

260

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Abstract-In this paper, an image accreditation technique by embedding digital watermarks in images is proposed. The proposed method for the digital watermarking is based on the wavelet transform. This is unlike most previous work, which used a random number of a sequence of bits as a watermark and where the watermark can only be detected by comparing an experimental threshold value to determine whether a sequence of random signals is the watermark. The proposed approach embeds a watermark with visual recognizable patterns, such as binary, gray, or color image in images by modifying the frequency part of the images. In the proposed approach, an original image is decomposed into wavelet coefficients. Then, multi-energy watermarking scheme based on the qualified significant wavelet tree (QSWT) is used to achieve the robustness of the watermarking. Unlike other watermarking techniques that use a single casting energy, QSWT adopts adaptive casting energy in different resolutions. The performance of the proposed watermarking is robust to a variety of signal distortions, such as JPEG, image cropping, sharpening, median filtering, and incorporating attacks.Index Terms-Digital watermark, discrete wavelet transform, image processing, JPEG compression, qualified significant wavelet tree.

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Efficient implementation of linear multiuser detectors

Cited by 6 publications

References 11 publications

An overlapping window decorrelating multiuser detector for DS-CDMA radio channels

An overlapping window decorrelating multiuser detector for DS-CDMA radio channels

Constrained minimum-BER multiuser detection

Hiding digital watermarks using multiresolution wavelet transform

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