  For a given polar code construction, the existing literature on puncturing
for polar codes focuses in finding the optimal puncturing pattern, and then
re-selecting the information set. This paper devotes itself to find the optimal
puncturing pattern when the information set is fixed. Puncturing the coded bits
corresponding to the worst quality bit channels, called the worst quality
puncturing (WQP), is proposed, which is analyzed to minimize the bit channel
quality loss at the punctured positions. Simulation results show that WQP
outperforms the best existing puncturing schemes when the information set is
fixed.
