Iterative multistage decoding of polar code based multilevel codes

Some multilevel codes which are constructed based on polar codes have been introduced recently, and show good performance with elaborately designed rates at each level and special multistage decoder. However, the multistage decoding is usually implemented in a sequential manner, which might yield poor performance at lower levels since the corresponding component codes are decoded without any information from higher levels, and the decoding errors occurred at previous stages could hardly be corrected. Thus, an iterative multistage decoding algorithm for polar code based multilevel codes is introduced in this paper, which could further improve the performance by feeding the reliable information obtained at higher levels back to the first level, and correct the decoding errors occurred at lower levels. Our proposed algorithm has only moderate complexity, and it is found that, the first iteration contributes the most performance improvement.