The Exponent of a Polarizing Matrix Constructed from the Kronecker   Product
  The asymptotic performance of a polar code under successive cancellation decoding is determined by the exponent of its polarizing matrix. We first prove that the partial distances of a polarizing matrix constructed from the Kronecker product are simply expressed as a product of those of its component matrices. We then show that the exponent of the polarizing matrix is shown to be a weighted sum of the exponents of its component matrices. These results may be employed in the design of a large polarizing matrix with high exponent. 
Myung-Kyu Lee and Kyeongcheol Yang
cs.IT math.IT