High-Speed Low-Power Complex Matched Filter for W-CDMA: Algorithm and VLSI-Architecture

Jie CHEN  Guoliang SHOU  Changming ZHOU  

IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences   Vol.E83-A   No.1   pp.150-157
Publication Date: 2000/01/25
Online ISSN: 
Print ISSN: 0916-8508
Type of Manuscript: PAPER
Category: Mobile Information Network and Personal Communications
weighted-sum operation,  parallel analog operational circuit,  mixed-signal LSI,  matched filter,  

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High-speed low-power matched filter plays an important role in the fast despreading of spread-signals in wideband code division multiple access (W-CDMA) mobile communications. In this paper, we describe the algorithm and the VLSI-architecture of a complex matched filter chip implemented by our proposed digital-controlled analog parallel operational circuits. The complex matched filter VLSI with variable taps from 4 to 128 is developed for despreading QPSK-modulated spread-signals for W-CDMA communications, which is fabricated by a 2-metal 0.8 µm CMOS technology. The dissipation power of the chip is 225 mW and 130 mW when it operates at the chip-rate of 20 MHz with the supply voltages of 3.0 V and 2.5 V, respectively, and it can be furthermore reduced to 62 mW at chip rate of 10 MHz when the supply voltage is lowered to 2.2 V. The 3-dB cut-off frequency of the fabricated chip is higher than 20 MHz for both 3.0 V and 2.5 V supplies. Comparing to pure digital matched filters, the massive and high-speed despreading operations of the spread-signals are directly carried out in analog domain. As a result, two high-speed analog-to-digital (A/D) converters operating at chip rate are omitted, the inner signal paths and the total dissipation power are greatly reduced.