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: "fundamental green tradeoffs progresses challenges and impacts on 5g networks"
  Abstract: With years of tremendous traffic and energy consumption growth, green radio has been valued not only for theoretical research interests but also for the operational expenditure reduction and the sustainable development of wireless communications. Fundamental green tradeoffs, served as an important framework for analysis, include four basic relationships: 1) spectrum efficiency versus energy efficiency; 2) deployment efficiency versus energy efficiency; 3) delay versus power; and 4) bandwidth versus power. In this paper, we first provide a comprehensive overview on the extensive on-going research efforts and categorize them based on the fundamental green tradeoffs. We will then focus on research progresses of 4G and 5G communications, such as orthogonal frequency division multiplexing and non-orthogonal aggregation, multiple input multiple output, and heterogeneous networks. We will also discuss potential challenges and impacts of fundamental green tradeoffs, to shed some light on the energy efficient research and design for future wireless networks.

Connected through hyperedge HE-1 (induced by source paper "beamforming optimization for intelligent reflecting surface assisted mimo a sum path gain maximization approach"):
  with members:
    - "cascaded channel estimation for large intelligent metasurface assisted massive mimo"
    - "beamforming optimization for wireless network aided by intelligent reflecting surface with discrete phase shifts"
    - "towards smart and reconfigurable environment intelligent reflecting surface aided wireless network"

Connected through hyperedge HE-2 (induced by source paper "intelligent reflecting surface enhanced wireless network two timescale beamforming optimization"):
  with members:
    - "joint active and passive beamforming optimization for intelligent reflecting surface assisted swipt under qos constraints"
    - "intelligent reflecting surface with discrete phase shifts channel estimation and passive beamforming"
    - "miso wireless communication systems via intelligent reflecting surfaces"
    - "secure wireless communication via intelligent reflecting surface"
    - "cascaded channel estimation for large intelligent metasurface assisted massive mimo"
    - "capacity characterization for intelligent reflecting surface aided mimo communication"
    - "resource allocation for secure irs assisted multiuser miso systems"
    - "intelligent reflecting surface meets ofdm protocol design and rate maximization"

Connected through hyperedge HE-3 (induced by source paper "asymptotic max min sinr analysis of reconfigurable intelligent surface assisted miso systems"):
  with members:
    - "intelligent reflecting surface versus decode and forward how large surfaces are needed to beat relaying"
    - "large intelligent surface antennas lisa making reflective radios smart"
    - "asymptotic analysis of rzf over double scattering channels with mmse estimation"
    - "rfocus practical beamforming for small devices"
    - "resource allocation for secure irs assisted multiuser miso systems"
    - "enabling secure wireless communications via intelligent reflecting surfaces"
    - "enabling large intelligent surfaces with compressive sensing and deep learning"
    - "mimo assisted networks relying on large intelligent surfaces a stochastic geometry model"

Connected through hyperedge HE-4 (induced by source paper "joint active and passive beamforming for intelligent reflecting surface assisted massive mimo systems"):
  with members:
    - "joint active and passive beamforming optimization for intelligent reflecting surface assisted swipt under qos constraints"
    - "large intelligent surface antennas lisa making reflective radios smart"
    - "secure wireless communication via intelligent reflecting surface"
    - "cascaded channel estimation for large intelligent metasurface assisted massive mimo"
    - "enabling secure wireless communications via intelligent reflecting surfaces"
    - "secrecy rate maximization for intelligent reflecting surface assisted multi antenna communications"
    - "intelligent reflecting surface assisted secrecy communication via joint beamforming and jamming"
    - "towards smart and reconfigurable environment intelligent reflecting surface aided wireless network"

Connected through hyperedge HE-5 (induced by source paper "channel estimation method and phase shift design for reconfigurable intelligent surface assisted mimo networks"):
  with members:
    - "joint active and passive beamforming optimization for intelligent reflecting surface assisted swipt under qos constraints"
    - "bilinear recovery using adaptive vector amp"
    - "intelligent reflecting surface with discrete phase shifts channel estimation and passive beamforming"
    - "cascaded channel estimation for large intelligent metasurface assisted massive mimo"
    - "hybrid beamforming for reconfigurable intelligent surface based multi user communications achievable rates with limited discrete phase shifts"
    - "channel estimation for intelligent reflecting surface assisted multiuser communications"
    - "channel estimation and transmission for intelligent reflecting surface assisted thz communications"
    - "reliability analysis of large intelligent surfaces liss rate distribution and outage probability"

Connected through hyperedge HE-6 (induced by source paper "energy efficiency of distributed antenna systems with wireless power transfer"):
  with members:
    - "energy efficient swipt in iot distributed antenna systems"
    - "wirelessly powered backscatter communications waveform design and snr energy tradeoff"
    - "power allocation for secure swipt systems with wireless powered cooperative jamming"
    - "wireless information and power transfer nonlinearity waveform design and rate energy tradeoff"
    - "artificial noise aided secrecy information and power transfer in ofdma systems"
    - "information and energy cooperation in ofdm relaying protocols and optimization"
    - "secure and green swipt in distributed antenna networks with limited backhaul capacity"
    - "optimal resource allocation in full duplex wireless powered communication network"

Connected through hyperedge HE-7 (induced by source paper "towards smart and reconfigurable environment intelligent reflecting surface aided wireless network"):
  with members:
    - "beamforming optimization for wireless network aided by intelligent reflecting surface with discrete phase shifts"
    - "weighted sum power maximization for intelligent reflecting surface aided swipt"
    - "intelligent reflecting surface assisted secrecy communication via joint beamforming and jamming"
    - "enabling large intelligent surfaces with compressive sensing and deep learning"
    - "achievable rate maximization by passive intelligent mirrors"
    - "intelligent reflecting surface enhanced wireless network via joint active and passive beamforming"
    - "spectral and energy efficient wireless powered iot networks noma or tdma"
    - "beyond massive mimo the potential of data transmission with large intelligent surfaces"

Connected through hyperedge HE-8 (induced by source paper "beamforming optimization for wireless network aided by intelligent reflecting surface with discrete phase shifts"):
  with members:
    - "over the air computation via intelligent reflecting surfaces"
    - "miso wireless communication systems via intelligent reflecting surfaces"
    - "secure wireless communication via intelligent reflecting surface"
    - "passive beamforming and information transfer via large intelligent surface"
    - "towards smart and reconfigurable environment intelligent reflecting surface aided wireless network"
    - "achievable rate maximization by passive intelligent mirrors"
    - "intelligent reflecting surface enhanced wireless network via joint active and passive beamforming"
    - "beamforming optimization for intelligent reflecting surface with discrete phase shifts"

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)