Construction and analysis of polar and concatenated polar codes:   practical approach
  We consider two problems related to polar codes. First is the problem of polar codes construction and analysis of their performance without Monte-Carlo method. The formulas proposed are the same as those in [Mori-Tanaka], yet we believe that our approach is original and has clear advantages. The resulting computational procedure is presented in a fast algorithm form which can be easily implemented on a computer. Secondly, we present an original method of construction of concatenated codes based on polar codes. We give an algorithm for construction of such codes and present numerical experiments showing significant performance improvement with respect to original polar codes proposed by Ar\i kan. We use the term \emph{concatenated code} not in its classical sense (e.g. [Forney]). However we believe that our usage is quite appropriate for the exploited construction. Further, we solve the optimization problem of choosing codes minimizing the block error of the whole concatenated code under the constraint of its fixed rate. 
Gregory Bonik, Sergei Goreinov, Nickolai Zamarashkin
cs.IT math.IT