在本文中，我們提出了一種編碼器的“雙準循環低密度奇偶校驗碼”(Double Quasicyclic
Low-Density Parity Check Code) 特殊結構。由於5G 具有伸縮性、低複雜度和低延
遲的要求，我們提出雙準循環低密度奇偶校驗碼來實現這些需求。這種雙準循環低密度奇
偶校驗矩陣具有雙移位循環的特點，所以編碼器不需要先求出反矩陣，可以直接用簡單的
移位暫存器結構來實現。當使用這種特殊結構時，我們可以減少編碼準循環低密度奇偶校
驗碼的複雜度。由於雙循環特性，雙準循環低密度奇偶校驗碼的編碼結構對硬體比較友
善。此外，矩陣每行1 個數均為3 的性質有利於降低編解碼器的複雜度。根據這些概念，
我們進行了許多的設計，如編碼器，解碼器，混合自動重複請求和5G 基本圖的修改，以
滿足5G 規範。在吞吐量和延遲部分，我們達到低延遲和高吞吐量。在復雜度上，我們使
用雙移位循環結構來降低編碼的複雜度。在誤塊率性能方面，我們和Mediatek、Ericsson
等公司有相同的表現。在伸縮性方面，我們提出了從1/9 到1/3 的許多不同的碼率。在
混合自動重複請求方面，我們設計了兩種不同的實施例，分別是藉由矩陣堆疊以及符合
3GPP 架構的方式來實現。

In,this thesis, we propose a special structure ”Double Quasi-Cyclic Low-Density Parity
Check Code (DQC-LDPC)” for channel encoder and decoder. Since 5G has the requirement
of flexibility, low complexity and low latency, we propose the DQC-LDPC Code to achieve
these demands. This DQC-LDPC parity check matrix has characteristic of double shift
circulant so that the encoder can be implemented by simple shift register structure instead
of using matrix inverse. When using this special structure, we can reduce the complexity
for encoding QC-LDPC codes. The encoding structure of DQC-LDPC is hardware friendly
because of the double circulant property. Also, the degree-3 property benefits the codec with
the lowest complexity. According to these concepts, we make lots of design such as encoder,
decoder, Hybrid Automatic Repeat Request and modification of base graph for 5G to meet
the 5G specifications. In the part of throughput and latency, we reach low latency and
high throughput. In the complexity, we use the double shift circulant structure to reduce
the complexity for encode. In the part of block error rate performance, we have the same
performance with other company such as Mediatek and Ericsson. In terms of flexibility, we
propose many different code rate from 1/9 to 1/3.

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