 LLR values iteratively through right-to-left and left-to-right iterations using the same update functions that were used in LDPC domain. For finite length codes, BP decoder out- performs SC decoder in terms of BER performance. Channel polarization is the concept upon which the polar codes are built. It is the process through which N distinct channels are generated W I<i<N from N independent copies of a binary-input discrete memoryless channel. The N generated channels are polarized and have mutual information either close to 0 (i.e., noisy channels) or close to 1 (i.e., noiseless channels). The synthesized channels become perfectly noisy/noiseless as N approaches infinity. The process of channel polarization consists of two phases namely channel combin- ing and channel splitting. In the former phase, N distinct channels are created in n = log2N steps, through recursively combining N copies of a binary-input discrete memoryless channel to form a vector channel WN:XN YN, , where N must be an integer power of two. In the second phase the channel WN is split into N binary-input channels X Xi-1. i < N. Uncoded information bits are transmitted over the reliable or noiseless channels with rate 1 and frozen bits are transmitted over the unreliable or noisy channels [33,34]. Polar code construction is the process of selecting the set of K good channels out of N channels over which uncoded information bits will be transmitted. The selection of the information set A is done in a channel dependent manner. For finite-length polar codes, the synthesized channels are not fully polarized. Bit errors over the quasi-polarized channels are inevitable. Thus the polar code construction phase is critical to obtain the best possible performance. To construct a polar code, the K reliable channels are chosen to minimize the sum of their Bhattacharyya parameter values EiEAZ(W) in order to minimize the upper New Radio Access Physical Layer Aspects (Part 2) 519 bound on the block error probability of the constructed polar code. For the bin