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OpenCL을 활용한 CPU와 GPU 에서의 CMMB LDPC 복호기 병렬화
박주열,홍정현,정기석,Park, Joo-Yul,Hong, Jung-Hyun,Chung, Ki-Seok 대한임베디드공학회 2016 대한임베디드공학회논문지 Vol.11 No.6
Recently, Open Computing Language (OpenCL) has been proposed to provide a framework that supports heterogeneous computing platforms. By using an OpenCL framework, digital communication systems can support various protocols in a unified computing environment to achieve both high portability and high performance. This article introduces a parallel software decoder of Low Density Parity Check (LDPC) codes for China Multimedia Mobile Broadcasting (CMMB) on a heterogeneous platform. Each step of LDPC decoding has different parallelization characteristics. In this paper, steps suitable for task-level parallelization are executed on the CPU, and steps suitable for data-level parallelization are processed by the GPU. To improve the performance of the proposed OpenCL kernels for LDPC decoding operations, explicit thread scheduling, loop-unrolling, and effective data transfer techniques are applied. The proposed LDPC decoder achieves high performance by using heterogeneous multi-core processors on a unified computing framework.
SNR 예측 정보 기반 적응형 Modified UMP-BP LDPC 복호기 설계
박주열,조걸,정기석,Park, Joo-Yul,Cho, Keol,Chung, Ki-Seok 대한임베디드공학회 2009 대한임베디드공학회논문지 Vol.4 No.4
As 4G mobile communication systems require high transmission rates with reliability, the need for efficient error correcting code is increasing. In this paper, a novel LDPC (Low Density Parity Check) decoder is introduced. The LDPC code is one of the most popular error correcting codes. In order to improve performance of the LDPC decoder, we use SNR (Signal-to-Noise Ratio) estimation results to adjust coefficients of modified UMP-BP (Uniformly Most Probable Belief Propagation) algorithm which is one of widely-used LDPC decoding algorithms. An advantage of Modified UMP-BP is that it is amenable to implement in hardware. We generate the optimal values by simulation for various SNRs and coefficients, and the values are stored in a look-up table. The proposed decoder decides coefficients of the modified UMP-BP based on SNR information. The simulation results show that the BER (Bit Error Rate) performance of the proposed LDPC decoder is better than an LDPC decoder using a conventional modified UMP-BP.
과공정 Al-Si 합금의 초정 Si 미세조직변화에 미치는 P 첨가와 fading 시간의 영향
박주열 ( Joo Yul Park ),김억수 ( Eok Soo Kim ),이광학 ( Kwang Hak Lee ) 한국주조공학회 2004 한국주조공학회지 Vol.24 No.2
N/A Mechanical property of hypereutectic Al-Si alloy is changed according to size and distribution of primary Si. Consequently, the study on the refinement for primary Si is progressed for a long time. But such effect of refinement comes out fading phenomena with the lapse of time. Therefore, this study investigated the optimum condition of primary Si refinement for hypereutectic Al-Si alloy. And we observed various primary Si size with P`s fading phenomena. The experiment results were as follows. For experiment of primary Si refinement, we made hypereutectic Al-Si alloy with various amounts of P addition. As a result of experiment, we obtained the fine microstructure at 0.01wt.%P. And the optimum condition of P addition, for reventing from growth of primary Si by P fading, is estimated 0.1wt.%P.
TMR 구조에서의 백업과 복원을 활용한 안정성 및 신뢰성 향상 임베디드 시스템 구현
박주열(Joo-Yul Park),이준환(Jun-Hwan Lee),김효상(Hyo-Sang Kim),김봉택(Bong-Taek Kim),정기석(Ki-Seok Chung) 한국철도학회 2011 한국철도학회 학술발표대회논문집 Vol.2011 No.10
The purpose of this paper is to explain the implementation method in order to enhance stability and reliability of embedded system. In this research Texas Instrument (TI)'s TMS570 MCU(Micro Controller Unit) is used to satisfy the standard of stability that is IEC 61508. IEC 61508 suggest SIL(Safety Integrity Level) from 1 to 4 and TMS570 is satisfied SIL3. Also TMS570 can provide several stability functions can be used in realtime system. To use such functions this paper suggest the solution about the defect that can be used in realtime system. In basic way TMR(Triple Modular Redundancy) suggested in addition to explain about the way to improve safety and reliability. Also this paper will suggest the method that reinforce the stability of calculation by using multiplex voter and memory.
박주열(Park Joo-Yul),김효상(Kim Hyo-Sang),이준환(Lee Joon-Hwan),김봉택(Kim Bong-Taek),정기석(Chung Ki-Seok) 한국철도학회 2008 한국철도학회 학술발표대회논문집 Vol.- No.-
As the railway transportation is getting faster and its operation speed has increased rapidly, its signal control has been complicated. For real time signal processing it is very important to prohibit any critical error from causing the system to malfunction. Therefore, handling complicated signals effectively while maintaining fault-tolerance capability is highly expected in modern railway transportation industry. In this paper, we suggest an SoC (Sytem-on-Chip) design method to integrate these complicated signal controlling mechanism with fault tolerant capability in a single chip. We propose an SoC solution which contains a high performance 32-bit embedded processor, digital filters and a PWM unit inside a single chip to implement ATO"s, ATC"s, ATP"s and ATS"s digital signal-processing units. We achieve an enhanced reliability against the calculation error by adding fault tolerance features to ensure the stability of each module.
OpenMP를 이용한 철도신호에서의 LDPC 적용에 관한 연구
박주열(Park Joo-Yul),김효상(Kim Hyo-Sang),박태기(Park Tae-ki),김봉택(Kim Bong-Taek),정기석(Chung Ki-Seok) 한국철도학회 2009 한국철도학회 학술발표대회논문집 Vol.2009 No.11월
There have been lots of researches for High Performance Digital Signal Processing performance enhancement on a multi-core processor. These kinds of parallelizing can enable massive signal processing, so we can have advantage's of processing various of signal processing standards without additional DSP's or other accelerating hardwares. In this paper we introduce Low Density Parity Check(LDPC) which is one of the Foward Error Correction(FEC). And we have achieved computational time reduce by using OpenMP as a parallelizing scheme.