A 5.83pJ/bit/iteration High-Parallel Performance-Aware LDPC Decoder IP Core Design for WiMAX in 65nm CMOS

Xiongxin ZHAO  Zhixiang CHEN  Xiao PENG  Dajiang ZHOU  Satoshi GOTO  

Publication
IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences   Vol.E96-A   No.12   pp.2623-2632
Publication Date: 2013/12/01
Online ISSN: 1745-1337
DOI: 10.1587/transfun.E96.A.2623
Print ISSN: 0916-8508
Type of Manuscript: Special Section PAPER (Special Section on VLSI Design and CAD Algorithms)
Category: High-Level Synthesis and System-Level Design
Keyword: 
WiMAX,  bit-serial,  fully-parallel,  layered scheduling,  performance aware,  advanced dynamic quantization,  quasi-cyclic,  low-density parity-check codes,  

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Summary: 
In this paper, we propose a synthesizable LDPC decoder IP core for the WiMAX system with high parallelism and enhanced error-correcting performance. By taking the advantages of both layered scheduling and fully-parallel architecture, the decoder can fully support multi-mode decoding specified in WiMAX with the parallelism much higher than commonly used partial-parallel layered LDPC decoder architecture. 6-bit quantized messages are split into bit-serial style and 2bit-width serial processing lines work concurrently so that only 3 cycles are required to decode one layer. As a result, 12∼24 cycles are enough to process one iteration for all the code-rates specified in WiMAX. Compared to our previous bit-serial decoder, it doubles the parallelism and solves the message saturation problem of the bit-serial arithmetic, with minor gate count increase. Power synthesis result shows that the proposed decoder achieves 5.83pJ/bit/iteration energy efficiency which is 46.8% improvement compared to state-of-the-art work. Furthermore, an advanced dynamic quantization (ADQ) technique is proposed to enhance the error-correcting performance in layered decoder architecture. With about 2% area overhead, 6-bit ADQ can achieve the error-correcting performance close to 7-bit fixed quantization with improved error floor performance.