We call the puncturing to be regular if the same number
of bits are punctured for all the VNs in a Tanner graph and
irregular otherwise. We first develop the EXIT chart model for
regular puncturing with random selection of the VNs.
A. Random Selection of the VNs and Regular Puncturing
Let b ∈ {1, · · · , s} denote the number of punctured bits per
VN. Suppose the mother code is of rate r0. Then for a target
rate rl, the number of punctured VNs is given by