Design and Analysis of Delayed Bit-Interleaved Coded Modulation With LDPC Codes

This paper investigates the design and performance of delayed bit-interleaved coded modulation (DBICM) with low-density parity-check (LDPC) codes. For Gray labeled square M-ary quadrature amplitude (QAM) constellations, we investigate optimal delay scheme largest spectrum efficiency DBICM for a fixed maximum number time slots given signal-to-noise ratio. When analyzing capacity DBICM, find two important properties: improvement due to bits being mapped real imaginary parts transmitted symbols are independent each other; pair schemes having identical bit-channel lead equivalent capacity. Using these properties, efficiently optimize any uniform Gray-QAM systems. Furthermore, properties enable efficient LDPC code designs regarding unequal error protection via type classifications. Moreover, use protograph-based extrinsic information transfer charts jointly degree distributions channel assignments codes propose constrained progressive edge growth like algorithm construct bit-interleavers taking distinctive bit-channel's into account. Simulation results demonstrate that designed systems significantly outperform BICM