Abstract:

To improve decoding performance, a concatenated polar codes coding scheme is designed which uses classical block codes as outer codes and polar codes as inner codes. The information bits with low confidence of the sub-channel are first encoded by the outer code. Then, all information bits and the parity check bits generated by the outer code are put into the polar encoder. It is shown that allocating the most trusted sub-channels to the parity check bits generated by the outer code can improve the performance of the proposed scheme, i.e., a lower decoding error probability can be achieved. A modified successive cancellation list decoder is also proposed. This decoding algorithm chooses the one with the highest correct probability of all the checked decoding results as the final output. Simulation results show that when the code length is 128 and the error frame rate is 10^-2, the proposed scheme has a gain of 0.25dB over the polarization code scheme with cyclic redundancy check.

Key words: polar codes, block codes, concatenated, successive cancellation list decode algorithm