基于星座图分割的稀疏码分多址接入码本设计OA

To address the difficulty in balancing the minimum Euclidean distance between composite constellation points and the average power in sparse code multiple access(SCMA)codebooks designed using the mother constellation rotation method,this paper proposes an SCMA codebook design method based on composite constellation partitioning.Unlike the conventional approach of generating user codebooks through transformations of a mother constellation,the proposed method directly designs the composite constellation on channel resource blocks,ensuring that the minimum Euclidean distance between constellation points meets the required constraints.The composite constellation is then partitioned into user sub-constellations,which are further mapped and expanded into user-specific codebooks.Theoretical analysis shows that,under the condition of equal average power,the minimum Euclidean distance between constellation points in the proposed composite constellation is improved by 3.94 dB compared with that of codebooks based on mother constellation rotation.Simulation results further demonstrate that,for the same bit error rate(BER),the proposed codebook achieves an approximate 2 dB gain in signal-to-noise ratio(SNR)compared with the conventional method.