Abstract: The next 6th generation of mobile communications system (6G) will reveal significant improvements in the key performance indicators and support diverse communication scenarios. These put forward higher requirements on the coded modulation technologies. In this paper, the advantages of the polar-coded modulation (PCM) in 6G are first investigated. Then, the principles of multilevel PCM (MLC-PCM) and bit-interleaved PCM (BIPCM) are discussed for the high spectral efficiency and low latency scenarios, respectively. In practical PCM systems, the existing construction methods encounter the problems of high complexity and poor flexibility. To solve these problems, a universal construction framework of PCM is proposed, and the operating procedures in MLC-PCM and BIPCM are also discussed in detail. This construction method utilizes “sum rate approximation” to assign code rates to polar component codes, which performs independently of the actual channel conditions and can significantly reduce the construction complexity of PCM. Simulation results further verify its flexibility and universality with better performance than the 5G low-density parity-check (LDPC)- coded modulation schemes.

Key words: the sixth generation of mobile communications system, polar codes, polar-coded modulation, code construction