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: "millimeter wave communication with non orthogonal multiple access for 5g"
  Abstract: To further improve the system capacity for 5G, we explore the integration of non-orthogonal multiple access (NOMA) in mmWave communications (mmWave-NOMA) for future 5G systems. Compared with the conventional NOMA, the distinguishing feature of mmWave-NOMA is that, it is usually characterized by transmit/receive beamforming with large antenna arrays. In this paper, we focus on the design challenges of mmWave-NOMA due to beamforming. Firstly, we study how beamforming affects the sum-rate performance of mmWave-NOMA, and find that with conventional single-beam forming, the performance may be offset by the relative angle between NOMA users. Then, we consider multi-beam forming for mmWave-NOMA, which is shown to be able to achieve promising performance enhancement as well as robustness. We further investigate the challenging joint design of the intertwined power allocation and user pairing for mmWave-NOMA. We also discuss the challenges and propose some potential solutions in detail. Finally, we consider hybrid spatial division multiple access (SDMA) and NOMA in mmWave communications, where some possible system configurations and the corresponding solutions are discussed to address the multi-user issues including multi-user precoding and multi-user interference (MUI) mitigation.

Connected through hyperedge HE-1 (induced by source paper "multi beam noma for hybrid mmwave systems"):
  with members:
    - "on low resolution adcs in practical 5g millimeter wave massive mimo systems"
    - "a multi beam noma framework for hybrid mmwave systems"
    - "rate splitting multiple access for downlink communication systems bridging generalizing and outperforming sdma and noma"
    - "optimal resource allocation for power efficient mc noma with imperfect channel state information"
    - "optimal user scheduling and power allocation for millimeter wave noma systems"
    - "spectrum and energy efficient beamspace mimo noma for millimeter wave communications using lens antenna array"
    - "multi user precoding and channel estimation for hybrid millimeter wave systems"
    - "joint power allocation and beamforming for non orthogonal multiple access noma in 5g millimeter wave communications"

Connected through hyperedge HE-2 (induced by source paper "a multi beam noma framework for hybrid mmwave systems"):
  with members:
    - "optimal resource allocation for power efficient mc noma with imperfect channel state information"
    - "optimal user scheduling and power allocation for millimeter wave noma systems"
    - "spectrum and energy efficient beamspace mimo noma for millimeter wave communications using lens antenna array"
    - "multi user precoding and channel estimation for hybrid millimeter wave systems"
    - "power efficient resource allocation for mc noma with statistical channel state information"
    - "a survey of downlink non orthogonal multiple access for 5g wireless communication networks"
    - "optimal joint power and subcarrier allocation for full duplex multicarrier non orthogonal multiple access systems"
    - "a minorization maximization method for optimizing sum rate in the downlink of non orthogonal multiple access systems"

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)