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: "fundamentals of the downlink green coverage and energy efficiency in heterogeneous networks"
  Abstract: This paper studies the proposed green (energy-efficient) coverage probability, link and network energy efficiencies in the downlink of a heterogeneous cellular network (HetNet) consisting of $K$ independent Poisson point processes (PPPs) of base stations (BSs). The important statistical properties of the universal (general) cell association functions are first studied and the cell load statistics for power-law cell association functions, which can characterize the accurate void cell probability of a BS in every tier, is also derived. A simple and feasible green channel-aware cell association (GCA) scheme is proposed and the green coverage probability is also proposed for any particular cell association scheme, such as the maximum received power association (MRPA) and nearest base station association (NBA) schemes. Then the link and network energy efficiencies are proposed to characterize the mean spectrum efficiency per unit power consumption for a BS and the mean area spectrum efficiency for a HetNet, respectively. All the tight bounds on the green coverage probability, link and network energy efficiencies for the GCA, MRPA and NBA schemes are found. They are theoretically shown to pose the fundamental maximum limits on the link and network energy efficiencies achieved by any other cell association schemes and such a fact is validated by numerical results as well.

Connected through hyperedge HE-1 (induced by source paper "modeling and performance analysis in cache enabled millimeter wave hetnets with access and backhaul integration"):
  with members:
    - "modeling and analysis of d2d millimeter wave networks with poisson cluster processes"
    - "a unified asymptotic analysis of area spectral efficiency in ultradense cellular networks"
    - "downlink cellular network analysis with los nlos propagation and elevated base stations"
    - "modeling analysis and optimization of coded caching in small cell networks"
    - "dense small cell networks from noise limited to dense interference limited"
    - "coverage in downlink heterogeneous mmwave cellular networks with user centric small cell deployment"
    - "caching at the wireless edge design aspects challenges and future directions"
    - "energy efficiency of downlink networks with caching at base stations"

Connected through hyperedge HE-2 (induced by source paper "ultra reliable and low latency communications using proactive multi cell association"):
  with members:
    - "wireless channel dynamics and robustness for ultra reliable low latency communications"
    - "resource allocation and harq optimization for urllc traffic in 5g wireless networks"
    - "reliable transmission of short packets through queues and noisy channels under latency and peak age violation guarantees"
    - "energy latency tradeoff in ultra reliable low latency communication with retransmissions"
    - "joint uplink and downlink resource configuration for ultra reliable and low latency communications"
    - "a statistical learning approach to ultra reliable low latency communication"
    - "heterogeneous networks with power domain noma coverage throughput and power allocation analysis"
    - "cross layer optimization for ultra reliable and low latency radio access networks"

Connected through hyperedge HE-3 (induced by source paper "coverage and handoff analysis of 5g fractal small cell networks"):
  with members:
    - "modeling and analyzing millimeter wave cellular systems"
    - "a novel millimeter wave channel simulator and applications for 5g wireless communications"
    - "vehicular communications for 5g cooperative small cell networks"
    - "analysis of human body blockage in urban millimeter wave cellular communications"
    - "a dual directional path loss model in 5g wireless fractal small cell networks"
    - "energy efficiency optimization of 5g radio frequency chain systems"
    - "wireless fractal cellular networks"
    - "joint millimeter wave and microwave resources allocation in cellular networks with dual mode base stations"

Connected through hyperedge HE-4 (induced by source paper "fundamentals of simultaneous wireless information and power transmission in heterogeneous networks a cell load perspective"):
  with members:
    - "modeling and analysis of cellular networks using stochastic geometry a tutorial"
    - "wireless power transfer in massive mimo aided hetnets with user association"
    - "traffic management for heterogeneous networks with opportunistic unlicensed spectrum sharing"
    - "on the limits of coexisting coverage and capacity in multi rat heterogeneous networks"
    - "random cell association and void probability in poisson distributed cellular networks"
    - "optimal cell load and throughput in green small cell networks with generalized cell association"
    - "wireless networks with rf energy harvesting a contemporary survey"
    - "simultaneous information and energy transfer in large scale networks with without relaying"

Connected through hyperedge HE-5 (induced by source paper "on the effective energy efficiency of ultra reliable networks in the finite blocklength regime"):
  with members:
    - "on the effective capacity of mtc networks in the finite blocklength regime"
    - "ultra reliable communication via optimum power allocation for type i arq in finite block length"
    - "power minimization under statistical delay constraints for multi hop wireless industrial networks"
    - "blocklength limited performance of relaying under quasi static rayleigh channels"
    - "ultra reliable communication in 5g wireless systems"

Connected through hyperedge HE-6 (induced by source paper "full duplex heterogeneous networks with decoupled user association rate analysis and traffic scheduling"):
  with members:
    - "user selection and power allocation in full duplex multicell networks"
    - "downlink and uplink decoupling in two tier heterogeneous networks with multi antenna base stations"
    - "optimal joint power and subcarrier allocation for full duplex multicarrier non orthogonal multiple access systems"
    - "traffic management for heterogeneous networks with opportunistic unlicensed spectrum sharing"
    - "full duplex mimo small cell networks with interference cancellation"
    - "on the limits of coexisting coverage and capacity in multi rat heterogeneous networks"
    - "random cell association and void probability in poisson distributed cellular networks"
    - "why to decouple the uplink and downlink in cellular networks and how to do it"

Connected through hyperedge HE-7 (induced by source paper "coverage rate tradeoff analysis in mmwave heterogeneous cellular networks"):
  with members:
    - "downlink and uplink cell association with traditional macrocells and millimeter wave small cells"
    - "user association in 5g networks a survey and an outlook"
    - "physical layer security in millimeter wave cellular networks"
    - "gains of restricted secondary licensing in millimeter wave cellular systems"
    - "stochastic geometry modeling and performance evaluation of mmwave cellular communications"
    - "optimal cell load and throughput in green small cell networks with generalized cell association"
    - "on the feasibility of sharing spectrum licenses in mmwave cellular systems"
    - "tractable model for rate in self backhauled millimeter wave cellular networks"

Connected through hyperedge HE-8 (induced by source paper "heterogeneous networks with power domain noma coverage throughput and power allocation analysis"):
  with members:
    - "power domain non orthogonal multiple access noma in 5g systems potentials and challenges"
    - "non orthogonal multiple access in large scale heterogeneous networks"
    - "a survey on non orthogonal multiple access for 5g networks research challenges and future trends"
    - "nonorthogonal multiple access in large scale underlay cognitive radio networks"
    - "on the spectral efficiency and security enhancements of noma assisted multicast unicast streaming"
    - "energy efficient transmission design in non orthogonal multiple access"
    - "cooperative non orthogonal multiple access with simultaneous wireless information and power transfer"
    - "random cell association and void probability in poisson distributed 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)