A New Hybrid Structure for Concatenated Codes

Erasure codes play an important role in improving network performance. Adding erasure codes to QUIC can effectively reduce data retransmission times, leading to better network performance. However, the complexity of the RS codes used in QUIC-FEC is high. Using short polar codes can reduce complexity. However, short polar codes have poor erasure correction performance. To solve this problem, we first proposed a method of combining (7, 4) Hamming codes with short polar codes in parallel. After providing protection for the incompletely polarized channels, the performance was significantly improved while maintaining low complexity and delay. Subsequently, based on Tanner diagrams of polar codes and Monte Carlo simulations, we determined the key bits that had the significant impact on the performance of the parallel concatenated codes. Therefore, we proposed a new parallel-serial hybrid structure, using (7, 4) Hamming codes to provide additional protection for these key bits. The results showed that the performance of the hybrid concatenated codes was better than that of the parallel concatenated codes, even better than the polar codes with the same bit rate and nearly twice the length of hybrid concatenated codes. The hybrid scenario also outperformed the RS codes used in QUIC protocol to restore lost packets. This new hybrid concatenated scheme can also be directly extended to a wider range of component codes.