| Author: | Yu, Siqi |
| Title: | Decoding of 5G NR low-density parity-check codes |
| Advisors: | Lau, C. M. Francis (EEE) |
| Degree: | M.Sc. |
| Year: | 2023 |
| Department: | Department of Electrical and Electronic Engineering |
| Pages: | xvi, 59 pages : color illustrations |
| Language: | English |
| Abstract: | With the advent of the information age, communication plays an increasingly important role in the world. A good communication system must meet four core requirements: feasibility, reliability, security, and effectiveness. The explosive development of the fifth generation mobile communication system (5G) in recent years has placed higher demands on the high-speed transmission and reliability of communication. Channel coding, as an indispensable part of communication systems, can reduce error rates and improve communication quality. The 5G NR standard selects Low-Density Parity-Check (LDPC) codes as channel coding because LDPC codes have excellent performance approaching the Shannon limit and are easy to implement in hardware. Since its discovery, LDPC codes have undergone multiple improvements and have now been proven to be superior to 4G turbo codes. Research on the theory and implementation of 5G LDPC encoding and decoding has received widespread attention. In terms of construction, 5G NR LDPC adopts quasi-cyclic construction. The encoding method is to use the double diagonal structure of the basis matrix of the 5G NR standard for encoding. In terms of decoding, research has shown that the performance of layered decoding is superior to traditional flooding decoding. Compared to traditional flooding decoding, which only updates variable nodes once in one iteration, layered decoding updates in the order of layers in one iteration, with variable nodes updated multiple times, resulting in faster convergence speed. The update order of the layered decoding layer also has a significant impact on the performance of LDPC. For the previous static schedule, the least-punctured and highest-degree (LPHD) schedule will prioritize updating the layers with the least punctured bits (PBs). For layers with the same number of PBs, prioritize updating the layer with the highest row degree (RD). One-edge-punctured and lowest-degree (OE-LD) schedule assigns the highest priority to the layer with a priority of 1 PB and the second highest priority to the layer with the lowest RD. We can combine the two to obtain LP-LD schedule and reconsider the priority of LP and LD, as research has shown that LD has greater performance improvement. Subsequently, simulation experiments were conducted to verify the theory and prove that the performance of LD-LP schedule is indeed the best as the first two priority. In the simulation experiment stage, a 5G NR LDPC code with a BG of size 46 × 68 was used. Firstly, using a 1/3 bit rate, a simulation comparison was conducted on six decoding algorithms, and it was found that the performance of the LD-LP layered schedule was greater than that of the ordinary sequential layered schedule and the flooding schedule. Subsequently, the core part of the parity check matrix for the 4 layers was simulated, and a comparison of 24 update orders for all layers was conducted through simulation. Finally, it is proven that LD-LP is indeed the optimal solution as the first two priority. |
| Rights: | All rights reserved |
| Access: | restricted access |
Files in This Item:
| File | Description | Size | Format | |
|---|---|---|---|---|
| 8274.pdf | For All Users (off-campus access for PolyU Staff & Students only) | 4.97 MB | Adobe PDF | View/Open |
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