Abstract
The complex valued matched filter correlators consume maximum power in the DS/SS CDMA receivers. These correlators accumulate 1024 samples lying in the range −7 to +7. This accumulation needs 3 data bits, 1 sign bit and 10 extra bits for overflow. Hence, the correlator can be implemented as a cascade of 4-bit full adder and a 10-bit incrementer. As a ripple carry adder (RCA) consumes the least power among all the existing adder architectures, we have implemented the 4-bit adder as a RCA. Previous incrementers were implemented as ripple counters. In this paper we propose a novel incrementer which is faster than a ripple counter based incrementer. Hence, it can be operated at a reduced voltage resulting in considerable power reduction. The incrementer is implemented using multiplexers, AND gates and TSPC registers. The ripple-counter correlator and the proposed incrementer correlator were laid out in MAGIC using 0.5 μ CMOS technology followed by power estimation using HSPICE. It is shown that the proposed architecture requires 50% less power than a ripple counter based design.
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Sahoo, B., Parhi, K.K. A Low Power Correlator for CDMA Wireless Systems. The Journal of VLSI Signal Processing-Systems for Signal, Image, and Video Technology 35, 105–112 (2003). https://doi.org/10.1023/A:1023392022320
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DOI: https://doi.org/10.1023/A:1023392022320