• Title, Summary, Keyword: multi-size circular shifter

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Low-Complexity Multi-Size Circular Shifter for QC-LDPC Decoder Based on Two Serial Barrel-Rotators (두 개의 직렬 Barrel-Rotator를 이용한 QC-LDPC 복호기용 저면적 Multi-Size Circular Shifter)

  • Kang, Hyeong-Ju
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.19 no.8
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    • pp.1839-1844
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    • 2015
  • The low-density parity-check(LDPC) code has been adopted in many communication standards due to its error correcting performance, and the quasi-cyclic LDPC(QC-LDPC) is widely used because of implementation easiness. In the QC-LDPC decoder, a cyclic-shifter is required to rotate data in various sizes. This kind of cyclic-shifters are called multi-size circular shifter(MSCS), and this paper proposes a low-complexity structure for MSCS. In the conventional serially-placed two barrel-rotators, the unnecessary multiplexers are revealed and removed, leading to low-complexity. The experimental results show that the area is reduced by about 12%.

Low-Complexity and High-Speed Multi-Size Circular Shifter With Benes Network Control Signal Optimization for WiMAX QC-LDPC Decoder (Benes 네트워크 제어 신호 최적화를 이용한 WiMAX QC-LDPC 복호기용 저면적/고속 Multi-Size Circular Shifter)

  • Kang, Hyeong-Ju
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.19 no.10
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    • pp.2367-2372
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    • 2015
  • One of various low-density parity-check(LDPC) codes that has been adopted in many communication standards due to its error correction ability is a quasi-cyclic LDPC(QC-LDPC) code, which leads to comparable decoder complexity. One of the main blocks in the QC-LCDC code decoder is a multi-size circular shifter(MSCS) that can perform various size rotation. The MSCS can be implemented with many structures, one of which is based on Banes network. The Benes network structure can perform the normal MSCS operation efficiently, but it cannot use the properties coming from specifications like rotation sizes. This paper proposesd a scheme where the Benes network structure can use the rotation size property with the modification of the control signal generation. The proposed scheme is applied to the MSCS of IEEE 802.16e WiMAX QC-LDPC decoder to reduce the number of MUXes and the critical path delay.

Multi-Size Circular Shifter Based on Benes Network with High-Speed 3×3 Switch (고속 3×3 스위치를 이용한 Benes 네트워크 기반 Multi-Size Circular Shifter)

  • Kang, Hyeong-Ju
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.19 no.11
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    • pp.2637-2642
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    • 2015
  • The low-density parity check(LDPC) code is being widely used due to its outperformed error-correction ability. The decoder of the quasi-cyclic LDPC(QC-LDPC) codes, a kind of LDPC codes, requires a multi-size cyclic shifter(MSCS) performing rotation of various sizes. The MSCS can be implemented with a Benes network, which requires a $3{\times}3$ switch if the number of data to be rotated is a multiple of 3. This paper proposes a control signal generation with lower complexity and a faster $3{\times}3$ switch. For the experiment, the proposed schemes are applied to the MSCS of an IEEE 802.16e WiMAX QC-LDPC code decoder. The result shows that the delay is reduced by about 8.7%.