Optimization of Generalized VDMM for Protograph-Based LDPC Coded BICM

In this letter, we develop a generalized variable degree matched mapping (G-VDMM) framework to accommodate any protograph structure and modulation order in bit-interleaved coded modulation (BICM) systems deploying protograph-based low-density parity-check (P-LDPC) codes. To seek for the optimal G-VDMM scheme, we also propose an efficient algorithm requiring far less computational cost than a brute-force search. Both extrinsic information transfer (EXIT) analyses and simulations verify that our optimized interleaver exhibits better performance than conventional designs.