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: "green 5g heterogeneous networks through dynamic small cell operation"
  Abstract: Traditional macrocell networks are experiencing an upsurge of data traffic, and small-cells are deployed to help offload the traffic from macrocells. Given the massive deployment of small-cells in a macrocell, the aggregate power consumption of small-cells (though being low individually) can be larger than that of the macrocell. Compared to the macrocell base station (MBS) whose power consumption increases significantly with its traffic load, the power consumption of a small-cell base station (SBS) is relatively flat and independent of its load. To reduce the total power consumption of the heterogeneous networks (HetNets), we dynamically change the operating states (on and off) of the SBSs, while keeping the MBS on to avoid any service failure outside active small-cells. First, we consider that the wireless users are uniformly distributed in the network, and propose an optimal location-based operation scheme by gradually turning  off  the SBSs closer to the MBS. We then extend the operation problem to a more general case where users are nonuniformly distributed in the network. Although this problem is NP-hard, we propose a joint location and user density based operation scheme to achieve near-optimum (with less than 1% performance loss in our simulations) in polynomial time.

Connected through hyperedge HE-1 (induced by source paper "dynamic model for network selection in next generation hetnets with memory affecting rational users"):
  with members:
    - "a learning based coexistence mechanism for laa lte based hetnets"
    - "energy minimization for wireless communication with rotary wing uav"
    - "blocking probability and spatial throughput characterization for cellular enabled uav network with directional antenna"
    - "downlink and uplink cell association with traditional macrocells and millimeter wave small cells"
    - "physical layer security in millimeter wave cellular networks"
    - "5g ultra dense cellular networks"
    - "tractable model for rate in self backhauled millimeter wave cellular networks"
    - "what will 5g be"

Connected through hyperedge HE-2 (induced by source paper "energy efficient massive mimo through distributed precoder design"):
  with members:
    - "joint user scheduling and beam selection optimization for beam based massive mimo downlinks"
    - "harvest the potential of massive mimo with multi layer techniques"
    - "the concrete distribution a continuous relaxation of discrete random variables"
    - "massive mimo ten myths and one critical question"
    - "large scale convex optimization for dense wireless cooperative networks"
    - "distributed constrained optimization by consensus based primal dual perturbation method"
    - "massive mimo meets hetnet interference coordination through spatial blanking"
    - "distributed robust multicell coordinated beamforming with imperfect csi an admm approach"

Connected through hyperedge HE-3 (induced by source paper "base station on off switching in 5g wireless networks approaches and challenges"):
  with members:
    - "boost base station on off switching strategy for energy efficient massive mimo hetnets"
    - "energy aware traffic offloading for green heterogeneous networks"
    - "how many small cells can be turned off via vertical offloading under a separation architecture"
    - "what will 5g be"
    - "base station sleeping and resource allocation in renewable energy powered cellular networks"
    - "adaptive power management for wireless base stations in a smart grid environment"

Connected through hyperedge HE-4 (induced by source paper "adaptively directional wireless power transfer for large scale sensor networks"):
  with members:
    - "energy group buying with loading sharing for green cellular networks"
    - "wireless powered communication opportunities and challenges"
    - "spatial throughput maximization of wireless powered communication networks"
    - "user cooperation in wireless powered communication networks"
    - "energy beamforming with one bit feedback"
    - "wireless networks with rf energy harvesting a contemporary survey"
    - "multiuser miso beamforming for simultaneous wireless information and power transfer"
    - "simultaneous information and energy transfer in large scale networks with without relaying"

Connected through hyperedge HE-5 (induced by source paper "an overview of sustainable green 5g networks"):
  with members:
    - "ultra dense small cell networks turning density into energy efficiency"
    - "energy efficient small cell with spectrum power trading"
    - "wireless powered communication opportunities and challenges"
    - "millimeter wave mimo with lens antenna array a new path division multiplexing paradigm"
    - "how many small cells can be turned off via vertical offloading under a separation architecture"
    - "simultaneous wireless information and power transfer in modern communication systems"
    - "wireless networks with rf energy harvesting a contemporary survey"
    - "what will 5g be"

Connected through hyperedge HE-6 (induced by source paper "energy group buying with loading sharing for green cellular networks"):
  with members:
    - "comp meets smart grid a new communication and energy cooperation paradigm"
    - "bargaining based mobile data offloading"
    - "what will 5g be"
    - "joint energy and spectrum cooperation for cellular communication systems"
    - "cost aware green cellular networks with energy and communication cooperation"
    - "cooperative energy trading in comp systems powered by smart grids"
    - "energy cooperation in cellular networks with renewable powered base stations"
    - "green cellular networks a survey some research issues and challenges"

Connected through hyperedge HE-7 (induced by source paper "green networking in cellular hetnets a unified radio resource management framework with base station on off switching"):
  with members:
    - "self optimized coverage coordination in femtocell networks"
    - "power control in two tier femtocell networks"
    - "femtocell networks a survey"

Connected through hyperedge HE-8 (induced by source paper "dynamic base station operation in large scale green cellular networks"):
  with members:
    - "energy group buying with loading sharing for green cellular networks"
    - "energy harvesting wireless communications a review of recent advances"
    - "comp meets smart grid a new communication and energy cooperation paradigm"
    - "a general utility optimization framework for energy harvesting based wireless communications"
    - "spatial throughput maximization of wireless powered communication networks"
    - "a lyapunov optimization approach for green cellular networks with hybrid energy supplies"
    - "quantifying potential energy efficiency gain in green cellular wireless networks"
    - "base station sleeping and resource allocation in renewable energy powered cellular networks"

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)