As one of the great survivors of the plant kingdom, barnyard grasses (Echinochloa spp.) are the most noxious and common weeds in paddy ecosystems. Meanwhile, at least two Echinochloa species have been domesticated and cultivated as millets. In order to better understand the genomic forces driving the evolution of Echinochloa species toward weed and crop characteristics, we assemble genomes of three Echinochloa species (allohexaploid E. crus-galli and E. colona, and allotetraploid E. oryzicola) and re-sequence 737 accessions of barnyard grasses and millets from 16 rice-producing countries. Phylogenomic and comparative genomic analyses reveal the complex and reticulate evolution in the speciation of Echinochloa polyploids and provide evidence of constrained disease-related gene copy numbers in Echinochloa. A population-level investigation uncovers deep population differentiation for local adaptation, multiple target-site herbicide resistance mutations of barnyard grasses, and limited domestication of barnyard millets. Our results provide genomic insights into the dual roles of Echinochloa species as weeds and crops as well as essential resources for studying plant polyploidization, adaptation, precision weed control and millet improvements.

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Non-orthogonal multiple access (NOMA) assisted semi-grant-free (SGF) transmission has recently received much research attention, which can serve the grant-free (GF) users with the grant-based (GB) users' spectrum. In this paper, we first extend the SGF scheme with the best user scheduling (BU-SGF) to a more practical randomly deployed users system. Then, a cumulative distribution function (CDF)based scheduling aided SGF (CS-SGF) scheme is proposed to ensure fair admission probability for all GF users. Meanwhile, we analytically demonstrate that, for both BU-SGF and CS-SGF schemes, full diversity orders can be achieved only when the served users' data rate is capped. To address this issue, we propose an efficient power control strategy to relax such data rate constraint and further enhance the outage probability. In addition, after applying the proposed power control strategy, both schemes' outage performances are analyzed by utilizing stochastic geometry. Theoretic and simulation results demonstrate that, with the proposed power control strategy both schemes can achieve full diversity orders in all cases.

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