ANALYSIS OF LDPC AND POLAR CODE DECODING ALGORITHMS IN THE 5G STANDARD: EVALUATION OF COMPLEXITY AND EFFICIENCY

Abstract

This paper presents a detailed analysis of the physical layer architecture of the 5G New Radio (5G NR) standard, with a particular focus on the channel coding schemes and their decoding algorithms, which are essential to achieving the stringent performance requirements of next-generation wireless communication systems. The study explores the rationale behind the adoption of Low-Density Parity-Check (LDPC) codes for downlink and uplink data channels carrying large payloads, due to their excellent error correction capabilities and near-capacity performance. In parallel, Polar codes are examined as the optimal choice for control channels with short block lengths, particularly in uplink scenarios, owing to their low complexity and robustness in low-latency environments.

A comprehensive overview of key decoding algorithms for both LDPC and Polar codes is provided, including Belief Propagation (BP), Min-Sum, Offset Min-Sum (OMS), and Normalized Min-Sum (NMS) for LDPC decoding, and Successive Cancellation (SC), Successive Cancellation List (SCL), Cyclic Redundancy Check-aided SCL (CA-SCL), and SC Flip algorithms for Polar codes. The trade-offs between computational complexity, decoding latency, and bit error rate (BER) performance are discussed in detail. Special attention is given to the performance of these decoding schemes under different service scenarios defined in 5G NR, including enhanced Mobile Broadband (eMBB), Ultra-Reliable Low Latency Communications (URLLC), and massive Machine Type Communications (mMTC). Simulation results demonstrate that while BP and Min-Sum offer acceptable performance with high parallelism for LDPC codes, CA-SCL decoding significantly enhances Polar code reliability, particularly when assisted by CRC verification.

The paper also addresses the impact of coding and decoding strategies on energy efficiency and system throughput in real-time 5G deployments. These findings are crucial for base station and user equipment manufacturers striving to balance complexity and performance. Overall, the insights presented contribute to the ongoing development and optimization of reliable, high-capacity, and low-latency 5G NR physical layer technologies.