Chao-Ming Chang

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—By introducing a new spreading approach and employing orthogonal signature sequences over frequency domain, we propose a new category of near-optimum multiuser detectors, whose complexity is as low as the detector in point-to-point communications , in the asynchronous additive white Gaussian noise (AWGN) channels. These newly proposed schemes do not have(More)
—Previous works on multiuser synchronization assumed that either timing recovery or carrier phase recovery schemes were available. Therefore, a generalized joint linear timing and carrier-phase estimation scheme to effectively estimate both the received timings and carrier phases at the same time is of paramount interest. Based on the idea to linearly(More)
By extending the frequency-domain approach [1] to practical scenarios such as the frequency-selective slowly fading channels, we justify the value of our proposed frequency-domain approach to multiuser detection in the DS-CDMA communications systems. With this frequency-domain approach which maintains the frequency-domain or-thogonality between different(More)
—Based on Neymann–Pearson criterion, a linear-complexity joint user identification, received timings, carrier phases and amplitudes estimation scheme is proposed without the limitations of existing approaches. Both mathematically and numerically , we justify the effectiveness of our proposed novel scheme for an arbitrary number of users in near–far(More)
The popularity of ketamine for recreational use among young people began to increase, particularly in Asia, in 2000. To gain more knowledge about the use of ketamine among high risk individuals, a respondent-driven sampling (RDS) was implemented among regular alcohol and tobacco users in the Taipei metropolitan area from 2007 to 2010. The sampling was(More)
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