  The 5th generation wireless systems (5G) standardization process of the 3rd
generation partnership project (3GPP) chose polar codes as a channel coding
scheme for the control channel. In case of downlink control information, polar
codes are concatenated with distributed distributed cyclic redundancy check
(CRC). Whereas CRC bits allow to improve the performance of successive
cancellation list (SCL) decoders by improving distance properties, distributed
CRC bits allow for path pruning and decoding early-termination. In this paper,
we show how to take advantage of the distributed CRC to improve SCL decoding,
analyzing various schemes having different earlytermination and error
correction properties. Simulation results compare the proposed decoding
schemes, showing different tradeoffs between error-correction performance and
early-termination with different decoder parameters.
