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: "channel capacity optimization using reconfigurable intelligent surfaces in indoor mmwave environments"
  Abstract: Indoor millimeter-wave (mmWave) environment channels are typically sparsely-scattered and dominated by a strong line-of-sight (LOS) path. Hence, any system optimization that is not centered around the transmission via the direct LOS path usually gives only limited gains. The recent introduction of reconfigurable intelligent surfaces (RISs), which have the potential to influence the propagation environment in a controlled manner, tends to change the previous paradigm. Motivated by this, we study the channel capacity optimization utilizing RISs in indoor mmWave environments. More precisely, we propose two optimization schemes that exploit the customizing capabilities of the RIS reflection elements to enhance the channel capacity. The first optimization scheme exploits only the adjustability of the RIS reflection elements; for this scheme we derive an approximate expression which explains the connection between the channel capacity gains and the system parameters. The second optimization scheme jointly optimizes the RIS reflection elements and the transmit phase precoder; for this scheme, we propose a low-complexity technique called global co-phasing to determine the phase shift values for use at the RIS. Simulation results show that the proposed optimization schemes achieve very significant channel capacity gains in systems with a large number of RIS elements.

Connected through hyperedge HE-1 (induced by source paper "mimo noma networks relying on reconfigurable intelligent surface a signal cancellation based design"):
  with members:
    - "intelligent reflecting surface assisted multiple access with user pairing noma or oma"
    - "enabling panoramic full angle reflection via aerial intelligent reflecting surface"
    - "performance analysis of intelligent reflecting surface assisted noma networks"
    - "miso wireless communication systems via intelligent reflecting surfaces"
    - "large intelligent surface antennas lisa making reflective radios smart"
    - "reflection probability in wireless networks with metasurface coated environmental objects an approach based on random spatial processes"
    - "capacity characterization for intelligent reflecting surface aided mimo communication"
    - "beamforming optimization for wireless network aided by intelligent reflecting surface with discrete phase shifts"

Connected through hyperedge HE-2 (induced by source paper "beyond max snr joint encoding for reconfigurable intelligent surfaces"):
  with members:
    - "intelligent reflecting surface versus decode and forward how large surfaces are needed to beat relaying"
    - "intelligent reflecting surface with discrete phase shifts channel estimation and passive beamforming"
    - "channel estimation for wireless communication systems assisted by large intelligent surfaces"
    - "reflection probability in wireless networks with metasurface coated environmental objects an approach based on random spatial processes"
    - "capacity characterization for intelligent reflecting surface aided mimo communication"
    - "intelligent reflecting surface irs enabled covert communications in wireless networks"
    - "secure transmission strategy for intelligent reflecting surface enhanced wireless system"
    - "channel estimation for intelligent reflecting surface assisted multiuser communications"

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)