Differentially encoded LDPC codes-part II: general case and code optimization
EURASIP Journal on Wireless Communications and Networking - Advances in Error Control Coding Techniques
Construction and iterative decoding of LDPC codes over rings for phase-noisy channels
EURASIP Journal on Wireless Communications and Networking - Advances in Error Control Coding Techniques
Detection by multiple trellises
IEEE Transactions on Communications
Performance of LDPC codes for satellite communication in ka band
WiCOM'09 Proceedings of the 5th International Conference on Wireless communications, networking and mobile computing
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In this paper, we consider serially concatenated schemes with outer novel and efficient low-density parity-check (LDPC) codes and inner modulations effective against channel impairments. With a pragmatic approach, we show how to design LDPC codes tailored for simple and robust modulation formats, such as differentially encoded (DE) modulations. The LDPC codes are optimized through the use of a recently proposed analysis technique based on extrinsic information transfer (EXIT) charts. In particular, we optimize, through a "clever" random walk in the parametric space, the degree distributions of the outer LDPC codes, obtaining significant insights on the impact of such distributions on the performance of the proposed concatenated schemes. The optimization is carried out for transmission over both the additive white Gaussian noise channel and a noncoherent channel. The performance predicted by the EXIT chart-based optimization is confirmed by results obtained via computer simulations, considering phase-shift keying and quadrature amplitude modulation at the transmitter side, and iterative demodulation/decoding at the receiver side. The significance of the proposed optimized design of LDPC-coded schemes with DE modulations is validated by the fact that standard nonoptimized LDPC codes perform poorly when used together with inner DE modulations.