Interleaved CRC-Polar Codes with Error Correction-Detection Decoding for Short-Packet URLLC

Short-packet transmission is a key enabler for ultra-reliable and low-latency communications (URLLC) in critical Internet of Things (IoT) systems. However, under finite block-lengths, conventional Polar codes usually suffer from a limited minimum Hamming distance, while heuristic cyclic redundancy check (CRC) placement and conventional CRC-aided successive cancellation list (CA-SCL) decoding often lead to suboptimal reliability-latency tradeoffs. To address these issues, this paper first proposes a novel interleaved CRC-Polar (ICRC-Polar) coding scheme that optimized via weight spectrum analysis. To reduce the prohibitive complexity of full spectrum enumeration, an efficient search algorithm utilizing the recursive properties of Polar cosets is developed to accurately estimate the dominant low-weight distribution. Based on the weight spectrum analysis, the interleaving pattern of ICRC-Polar codes is optimized to maximize the MHD. Furthermore, this paper proposes a cooperative decoding strategy based on error correction and detection patterns (ECDP), which dynamically configures distributed CRC bits of ICRC-Polar codes as either error detectors for early path pruning or error correctors to suppress error propagation. Simulation results demonstrate that the proposed ICRC-Polar scheme significantly improves the block error rate (BLER) performance, while substantially reducing decoding latency and computational complexity compared to conventional CRC-Polar scheme.