Reconfigurable intelligent surface(RIS)as a promising technology has been proposed to change weak communication environ-ments.However,most of the current resource allocation(RA)schemes have focused on RIS-assisted hom...Reconfigurable intelligent surface(RIS)as a promising technology has been proposed to change weak communication environ-ments.However,most of the current resource allocation(RA)schemes have focused on RIS-assisted homogeneous networks,and there is still no open works about RA schemes of RIS-assisted heterogeneous networks(HetNets).In this paper,we design an RA scheme for a RIS-assisted HetNet with non-orthogonal multiple access to improve spectrum efficiency and transmission rates.In particular,we jointly optimize the transmit power of the small-cell base station and the phase-shift matrix of the RIS to maximize the sum rates of all small-cell users,subject to the unit modulus constraint,the minimum signal-to-interference-plus-noise ratio constraint,and the cross-tier interference constraint for protecting communication quality of microcell users.An efficient suboptimal RA scheme is proposed based on the alternating iteration ap-proach,and successive convex approximation and logarithmic transformation approach.Simulation results verify the effectiveness of the pro-posed scheme in terms of data rates.展开更多
基金partially supported by the China National Key R&D Program under Grant No. 2021YFA1000502National Natural Science Foundation of China under Grant No. 62101492+4 种基金Zhejiang Provincial Natural Science Foundation of China under Grant No. LR22F010002Distinguished Young Scholars of the National Natural Science Foundation of ChinaNg Teng Fong Charitable Foundation in the form of ZJU-SUTD IDEA GrantZhejiang University Education Foundation Qizhen Scholar FoundationFundamental Research Funds for the Central Universities under Grant No. 2021FZZX001-21
文摘Reconfigurable intelligent surface(RIS)as a promising technology has been proposed to change weak communication environ-ments.However,most of the current resource allocation(RA)schemes have focused on RIS-assisted homogeneous networks,and there is still no open works about RA schemes of RIS-assisted heterogeneous networks(HetNets).In this paper,we design an RA scheme for a RIS-assisted HetNet with non-orthogonal multiple access to improve spectrum efficiency and transmission rates.In particular,we jointly optimize the transmit power of the small-cell base station and the phase-shift matrix of the RIS to maximize the sum rates of all small-cell users,subject to the unit modulus constraint,the minimum signal-to-interference-plus-noise ratio constraint,and the cross-tier interference constraint for protecting communication quality of microcell users.An efficient suboptimal RA scheme is proposed based on the alternating iteration ap-proach,and successive convex approximation and logarithmic transformation approach.Simulation results verify the effectiveness of the pro-posed scheme in terms of data rates.
