Probability Shaping for High-Order Systems with DSC-LDPC Codes

The research on joint source-channel coding (JSCC) systems primarily employs low-order BPSK modulation. However, such low spectral efficiency modulation schemes cannot meet the demands of future high-speed communication. In real-world scenarios, source probabilities are often unequal. Therefore, introducing high-order modulation with a probability shaping model, combined with dual spatially coupled low-density parity-check (DSC-LDPC) codes, can better exploit system performance and further increase throughput.Utilizing the remaining source redundancy to achieve amplitude shaping gains, a novel approach called joint source-channel coded modulation (JSCCM) is proposed, serving as a solution based on probabilistic amplitude shaping (PAS). This paper suggests the combination of quadrature amplitude modulation (QAM) modulation with a DSC-LDPC-JSCC system and examines whether probability shaping techniques can further enhance the system.