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: "how many small cells can be turned off via vertical offloading under a separation architecture"
  Abstract: To further improve the energy efficiency of heterogeneous networks, a separation architecture called hyper-cellular network (HCN) has been proposed, which decouples the control signaling and data transmission functions. Specifically, the control coverage is guaranteed by macro base stations (MBSs), whereas small cells (SCs) are only utilized for data transmission. Under HCN, SCs can be dynamically turned off when traffic load decreases for energy saving. A fundamental problem then arises: how many SCs can be turned off as traffic varies? In this paper, we address this problem in a theoretical way, where two sleeping schemes (i.e., random and repulsive schemes) with vertical inter-layer offloading are considered. Analytical results indicate the following facts: 1) under the random scheme where SCs are turned off with certain probability, the expected ratio of sleeping SCs is inversely proportional to the traffic load of SC-layer and decreases linearly with the traffic load of MBS-layer; 2) the repulsive scheme, which only turns off the SCs close to MBSs, is less sensitive to the traffic variations; and 3) deploying denser MBSs enables turning off more SCs, which may help to improve network energy-efficiency. Numerical results show that about 50% SCs can be turned off on average under the predefined daily traffic profiles, and 10% more SCs can be further turned off with inter-layer channel borrowing.

Connected through hyperedge HE-1 (induced by source paper "base station switch off with mutual repulsion in fifth generation massive multi input multi output networks"):
  with members:
    - "toward a tractable delay analysis in ultra dense networks"
    - "spatial spectrum and energy efficiency of random cellular networks"
    - "5g ultra dense cellular networks"
    - "downlink performance of cellular systems with base station sleeping user association and scheduling"

Connected through hyperedge HE-2 (induced by source paper "cost effective cache deployment in mobile heterogeneous networks"):
  with members:
    - "on optimal geographical caching in heterogeneous cellular networks"
    - "cache size allocation in backhaul limited wireless networks"
    - "a learning based approach to caching in heterogenous small cell networks"
    - "optimal caching and user association in cache enabled heterogeneous wireless networks"
    - "on the delay of geographical caching methods in two tiered heterogeneous networks"
    - "mobility aware caching for content centric wireless networks modeling and methodology"
    - "wireless content caching for small cell and d2d networks"
    - "energy efficiency of downlink networks with caching at base stations"

Connected through hyperedge HE-3 (induced by source paper "emm energy aware mobility management for mobile edge computing in ultra dense networks"):
  with members:
    - "a survey on mobile edge computing the communication perspective"
    - "a non stochastic learning approach to energy efficient mobility management"
    - "delay optimal computation task scheduling for mobile edge computing systems"
    - "energy efficient resource allocation for mobile edge computation offloading"
    - "user centric mobility management in ultra dense cellular networks under spatio temporal dynamics"
    - "efficient multi user computation offloading for mobile edge cloud computing"
    - "mobility induced service migration in mobile micro clouds"
    - "five disruptive technology directions for 5g"

Connected through hyperedge HE-4 (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"
    - "green 5g heterogeneous networks through dynamic small cell operation"
    - "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-5 (induced by source paper "self sustaining caching stations toward cost effective 5g enabled vehicular networks"):
  with members:
    - "mobility aware caching for content centric wireless networks modeling and methodology"
    - "the price of fog a data driven study on caching architectures in vehicular networks"
    - "what will 5g be"

Connected through hyperedge HE-6 (induced by source paper "mobility aware modeling and analysis of dense cellular networks with c plane u plane split architecture"):
  with members:
    - "user mobility evaluation for 5g small cell networks based on individual mobility model"
    - "handoff rate and coverage analysis in multi tier heterogeneous networks"
    - "on stochastic geometry modeling of cellular uplink transmission with truncated channel inversion power control"
    - "what will 5g be"
    - "emerging technologies and research challenges for 5g wireless networks"
    - "downlink mimo hetnets modeling ordering results and performance analysis"
    - "joint resource partitioning and offloading in heterogeneous cellular networks"
    - "towards understanding the fundamentals of mobility in cellular networks"

Connected through hyperedge HE-7 (induced by source paper "an overview of sustainable green 5g networks"):
  with members:
    - "ultra dense small cell networks turning density into energy efficiency"
    - "green 5g heterogeneous networks through dynamic small cell operation"
    - "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"
    - "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-8 (induced by source paper "energy aware traffic offloading for green heterogeneous networks"):
  with members:
    - "what will 5g be"
    - "base station sleeping and resource allocation in renewable energy powered cellular networks"
    - "energy efficient resource allocation in ofdma systems with hybrid energy harvesting base station"
    - "fundamentals of heterogeneous cellular networks with energy harvesting"
    - "user association for load balancing in heterogeneous cellular networks"
    - "optimal packet scheduling on an energy harvesting broadcast link"
    - "optimal packet scheduling in an energy harvesting communication system"

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.NI(Networking and Internet Architecture)