  This paper presents a puncturing technique to design length-compatible polar
codes. The punctured bits are identified with the help of differential
evolution (DE). A DE-based optimization framework is developed where the sum of
the bit-error-rate (BER) values of the information bits is minimized. We
identify a set of bits which can be avoided for puncturing in the case of
additive white Gaussian noise (AWGN) channels. This reduces the size of the
candidate puncturing patterns. Simulation results confirm the superiority of
the proposed technique over other state-of-the-art puncturing methods.
