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VLSI Design
Volume 2013 (2013), Article ID 913018, 14 pages
http://dx.doi.org/10.1155/2013/913018
Research Article

LDPC Decoder with an Adaptive Wordwidth Datapath for Energy and BER Co-Optimization

1CSEE Department, University of Maryland, Baltimore County, MD 21250, USA
2ECE Department, University of California, Davis, MD 95616, USA

Received 10 September 2012; Accepted 25 December 2012

Academic Editor: Sungjoo Yoo

Copyright © 2013 Tinoosh Mohsenin et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

An energy efficient low-density parity-check (LDPC) decoder using an adaptive wordwidth datapath is presented. The decoder switches between a Normal Mode and a reduced wordwidth Low Power Mode. Signal toggling is reduced as variable node processing inputs change in fewer bits. The duration of time that the decoder stays in a given mode is optimized for power and BER requirements and the received SNR. The paper explores different Low Power Mode algorithms to reduce the wordwidth and their implementations. Analysis of the BER performance and power consumption from fixed-point numerical and post-layout power simulations, respectively, is presented for a full parallel 10GBASE-T LDPC decoder in 65 nm CMOS. A 5.10 mm2 low power decoder implementation achieves 85.7 Gbps while operating at 185 MHz and dissipates 16.4 pJ/bit at 1.3 V with early termination. At 0.6 V the decoder throughput is 9.3 Gbps (greater than 6.4 Gbps required for 10GBASE-T) while dissipating an average power of 31 mW. This is 4.6 lower than the state of the art reported power with an SNR loss of 0.35 dB at .