Path Metric Inherited SCL Decoding of Multilevel Polar-Coded Systems

Polar code-based techniques cooperating with the multilevel coding (MLC) structure are promising for short-packet communication scenarios. In this paper, we concern about how to properly implement the successive cancellation list (SCL) decoding in multilevel polar-coded systems. We show that when SCL decoding bridges adjacent component polar codes, the path metrics should be properly inherited such that the correct path can be well preserved. To tackle this, we propose a path metric inherited SCL decoding algorithm for multilevel polar-coded systems, which integrates the decoding of multiple component polar codes into a collaborative ensemble. Simulation results show that this carefully-designed SCL decoding algorithm is critical for the performance gain of the multilevel polar-coded system against the Turbo/LDPC-coded systems.