Why do we use polar for control channels and LDPC for data channels?

Hi all,

Why do we use polar for control channels and LDPC for data channels?

One reason I could find is Polar gives better performance for low SNR cases, it doesn’t give a noise floor.

Can someone help me with more eleborated answer?

Channel coding is based on LDPC codes, a code design which was originally proposed in the 1960s but forgotten for many years. They were “rediscovered” in the 1990s and found to be an attractive choice from an implementation perspective. From an error-correcting capability point of view, turbo codes, as used in LTE, can achieve similar performance, but LDPC codes can offer lower complexity, especially at higher code rates, and were therefore chosen for NR.

One reason I could find is that Polar is sequential decoding procedure.

So for high code blocks polar decoder can take more time comparative to LDPC.

Do anyone have any profiling number for Polar or LDPC?