Directed search decoding of polar codes with Reed-Solomon kernel

The directed search algorithm, introduced originally for decoding of polar codes with Arikan kernel, is generalized to the case of a Reed-Solomon kernel. The algorithm relies heavily on the knowledge of symbol subchannel error probabilities of the polarizing transformation. A method to approximate these probabilities is suggested. The proposed method results in almost the same complexity and performance as in the case of the decoder using exact values of error probabilities.