  We consider the joint design of polar coding and higher-order modulation
schemes for ever increased spectral efficiency. The close connection between
the polar code construction and the multi-level coding approach is described in
detail. Relations between different modulation schemes such as bit-interleaved
coded modulation (BICM) and multi-level coding (MLC) in case of polar-coded
modulation as well as the influence of the applied labeling rule and the
selection of frozen channels are demonstrated.
