human: Given a node-centered hypergraph: <hypergraph>, where nodes represent papers and hyperedges represent sets of papers co-cited by a source paper.

Details of the hypergraph:
Center node: "what role can noma play in massive mimo"
  Abstract: This paper seeks to answer a simple but fundamental question: what role can non-orthogonal multiple access (NOMA) play in massive multi-in multi-out (MIMO)? It is well established that power-domain NOMA schemes can outperform conventional orthogonal multiple access schemes in cellular networks. However, this fact does not imply that NOMA is the most efficient way to communicate in massive MIMO setups, where the base stations have many more antennas than there are users in the cell. These setups are becoming the norm in future networks and are usually studied by assuming spatial multiplexing of the users using linear multi-user beamforming. To answer the above-mentioned question, we analyze and compare the performance achieved by NOMA and multi-user beamforming in both non-line-of-sight and line-of-sight scenarios. We reveal that the latter scheme gives the highest average sum rate in massive MIMO setups. We also identify specific cases where NOMA is the better choice in massive MIMO and explain how NOMA plays an essential role in creating a hybrid of NOMA and multi-user beamforming that is shown to perform better than two standalone schemes do.

Connected through hyperedge HE-1 (induced by source paper "code domain noma in massive mimo when is it needed"):
  with members:
    - "what is the benefit of code domain noma in massive mimo"
    - "gaussian message passing for overloaded massive mimo noma"
    - "massive mimo has unlimited capacity"
    - "massive mimo performance tdd versus fdd what do measurements say"
    - "power domain non orthogonal multiple access noma in 5g systems potentials and challenges"
    - "fundamental limits of low density spreading noma with fading"
    - "massive mimo performance evaluation based on measured propagation data"
    - "a coordinated approach to channel estimation in large scale multiple antenna systems"

Connected through hyperedge HE-2 (induced by source paper "interplay between noma and other emerging technologies a survey"):
  with members:
    - "secure relaying in non orthogonal multiple access trusted and untrusted scenarios"
    - "securing downlink massive mimo noma networks with artificial noise"
    - "lens based millimeter wave reconfigurable antenna noma"
    - "noma an information theoretic perspective"
    - "joint power and time allocation for noma mec offloading"
    - "multi beam noma for hybrid mmwave systems"
    - "exploiting full half duplex user relaying in noma systems"
    - "energy efficient noma enabled heterogeneous cloud radio access networks"

Connected through hyperedge HE-3 (induced by source paper "a survey of rate optimal power domain noma schemes for enabling technologies of future wireless networks"):
  with members:
    - "generalized coordinated multipoint gcomp enabled noma outage capacity and power allocation"
    - "uav data collection over noma backscatter networks uav altitude and trajectory optimization"
    - "uav communications for 5g and beyond recent advances and future trends"
    - "when full duplex wireless meets non orthogonal multiple access opportunities and challenges"
    - "on optimizing vlc networks for downlink multi user transmission a survey"
    - "beam design and user scheduling for nonorthogonal multiple access with multiple antennas based on pareto optimality"
    - "spatial modulation assisted multi antenna non orthogonal multiple access"
    - "hybrid precoding based millimeter wave massive mimo noma with simultaneous wireless information and power transfer"

Connected through hyperedge HE-4 (induced by source paper "rate analysis of cell free massive mimo noma with three linear precoders"):
  with members:
    - "ubiquitous cell free massive mimo communications"
    - "interplay between noma and other emerging technologies a survey"
    - "downlink spectral efficiency of cell free massive mimo with full pilot zero forcing"
    - "signal processing for mimo noma present and future challenges"
    - "on the total energy efficiency of cell free massive mimo"
    - "power domain non orthogonal multiple access noma in 5g systems potentials and challenges"
    - "channel hardening and favorable propagation in cell free massive mimo with stochastic geometry"
    - "capacity comparison between mimo noma and mimo oma with multiple users in a cluster"

Connected through hyperedge HE-5 (induced by source paper "what is the benefit of code domain noma in massive mimo"):
  with members:
    - "gaussian message passing for overloaded massive mimo noma"
    - "massive mimo has unlimited capacity"
    - "fundamental limits of low density spreading noma with fading"

Question: Please tell me which class the center node belongs to. The 40 classes are: cs.NA(Numerical Analysis), cs.MM(Multimedia), cs.LO(Logic in Computer Science), cs.CY(Computers and Society), cs.CR(Cryptography and Security), cs.DC(Distributed, Parallel, and Cluster Computing), cs.HC(Human-Computer Interaction), cs.CE(Computational Engineering, Finance, and Science), cs.NI(Networking and Internet Architecture), cs.CC(Computational Complexity), cs.AI(Artificial Intelligence), cs.MA(Multiagent Systems), cs.GL(General Literature), cs.NE(Neural and Evolutionary Computing), cs.SC(Symbolic Computation), cs.AR(Hardware Architecture), cs.CV(Computer Vision and Pattern Recognition), cs.GR(Graphics), cs.ET(Emerging Technologies), cs.SY(Systems and Control), cs.CG(Computational Geometry), cs.OH(Other Computer Science), cs.PL(Programming Languages), cs.SE(Software Engineering), cs.LG(Machine Learning), cs.SD(Sound), cs.SI(Social and Information Networks), cs.RO(Robotics), cs.IT(Information Theory), cs.PF(Performance), cs.CL(Computation and Language), cs.IR(Information Retrieval), cs.MS(Mathematical Software), cs.FL(Formal Languages and Automata Theory), cs.DS(Data Structures and Algorithms), cs.OS(Operating Systems), cs.GT(Computer Science and Game Theory), cs.DB(Databases), cs.DL(Digital Libraries), cs.DM(Discrete Mathematics). Directly output the class name.

gpt: cs.IT(Information Theory)