Browsing by Author "Wei, Che-Ho"

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A High-Speed Real-Time Binary BCH Decoder
(1993-04-01)
Wei, Shyue-Win
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Wei, Che-Ho
;
電子工程學系及電子研究所
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電信研究中心
;
Department of Electronics Engineering and Institute of Electronics
A high-speed real-time decoder for t-error-correcting binary Bose-Chaudhuri-Hocquenghem (BCH) codes based on a modified step-by-step decoding algorithm is presented. The average operation cycles for decoding each received word is just equal to the block length of the codeword. The decoder is constructed by three modules: the syndrome module, the comparison module, and the error corrector. Since all of the modules can be implemented by systolic circuits, the operation data rate of this decoder can theoretically be up to a rate of the inverse of two logic-gate delays. Based on different VLSI technologies, such as CMOS, BiCMOS and Gab, the decoder can be operated from approximately several hundreds megabits per second to the order of gigabits per second. Thus, the decoder can be applied in the broadband service and video processing. Besides, by avoiding the use of inverse operation in the step-by-step decoding method, the circuit complexity of this decoder can be much less than the standard algebraic method in which the inverse operation is usually required for finding the coefficients of the error-location polynomial. The detailed circuit diagrams of the comparison module and error corrector for the double- and triple-error-correcting binary BCH codes are given for illustration.
Pilot-channel-aided successive interference cancellation for uplink WCDMA systems
(2007-07-01)
Tang, Chih-Hsuan
;
Wei, Che-Ho
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
In this paper, a pilot-channel-aided successive-interference-cancellation (SIC) scheme for uplink wideband code-division multiple-access system is presented. In order to alleviate the interferences from other users' pilot-channel signals, this scheme performs pilot-channel-signal removal (PCSR) for all users before data detection. Three ordering methods for successive-cancellation process are discussed and compared in the aspect of architecture, latency, computational complexity, and error performance. In addition, channel estimation performed independently with the pilot-channel of each user is taken into consideration in the analyses. The pilot-channel-aided SIC performs variously with different ordering methods, pilot-to-traffic amplitude. ratios, grouping intervals, power-distribution ratios, and propagation conditions. From our analyses and simulations, the SIC with ordering based on RAKE outputs at the first stage in properly chosen grouping interval is suggested over multipath fading channels when error performance and practicability are jointly concerned.