Throughput-Optimized Multi-Rate LDPC Codes for Satellite Communication Systems with Restricted Decoder Complexity

Multi-rate low-density parity-check (LDPC) codes are widely used in satellite communication (SatCom) systems due to their outstanding performance and adaptable code rates. However, their hardware decoder implementations typically require high hardware resources and many decoding iterations, which pose challenges for high-throughput applications in resource-constrained, high-data-rate SatCom scenarios. To this end, the design of throughput-optimized multi-rate LDPC codes is investigated, aiming to tackle the decoder implementation problem from the perspective of practical code design. Specifically, a multi-rate weighted normalized throughput metric is introduced, which considers two key factors, i.e., the number of non-zero elements in the parity-check matrix and the required decoding iterations. Then, the throughput-optimized multi-rate code design problem is formulated to maximize the proposed metric under given decoding threshold constraints, which is later solved using a protomatrix search method based on the differential evolution (DE) algorithm. Finally, three multi-rate LDPC codes are optimized for scenes with different code rate usage frequencies. Their performance is extensively evaluated both theoretically and numerically. Results demonstrate that the proposed codes outperform other similar LDPC codes in the literature, showing a throughput increase of 20% to 30% under the same hardware resource consumption.