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: "structured spectrum allocation and user association in heterogeneous cellular networks"
  Abstract: We study joint spectrum allocation and user association in heterogeneous cellular networks with multiple tiers of base stations. A stochastic geometric approach is applied as the basis to derive the average downlink user data rate in a closed-form expression. Then, the expression is employed as the objective function in jointly optimizing spectrum allocation and user association, which is of non-convex programming in nature. A computationally efficient Structured Spectrum Allocation and User Association (SSAUA) approach is proposed, solving the optimization problem optimally when the density of users is low, and near-optimally with a guaranteed performance bound when the density of users is high. A Surcharge Pricing Scheme (SPS) is also presented, such that the designed association bias values can be achieved in Nash equilibrium. Simulations and numerical studies are conducted to validate the accuracy and efficiency of the proposed SSAUA approach and SPS.

Connected through hyperedge HE-1 (induced by source paper "on the energy efficient deployment for ultra dense heterogeneous networks with nlos and los transmissions"):
  with members:
    - "sinr and throughput of dense cellular networks with stretched exponential path loss"
    - "effect of densification on cellular network performance with bounded pathloss model"
    - "modeling and analysis of cellular networks using stochastic geometry a tutorial"
    - "user association in 5g networks a survey and an outlook"
    - "coverage analysis of heterogeneous cellular networks in urban areas"
    - "stochastic geometric analysis of energy efficient dense cellular networks"
    - "joint downlink cell association and bandwidth allocation for wireless backhauling in two tier hetnets with large scale antenna arrays"
    - "physical layer security in heterogeneous cellular networks"

Connected through hyperedge HE-2 (induced by source paper "analysis of lte a heterogeneous networks with sir based cell association and stochastic geometry"):
  with members:
    - "modeling and analysis of cellular networks using stochastic geometry a tutorial"
    - "optimizing user association and spectrum allocation in hetnets a utility perspective"
    - "an overview of load balancing in hetnets old myths and open problems"
    - "joint resource partitioning and offloading in heterogeneous cellular networks"
    - "offloading in heterogeneous networks modeling analysis and design insights"
    - "heterogeneous cellular networks with flexible cell association a comprehensive downlink sinr analysis"
    - "user association for load balancing in heterogeneous cellular networks"
    - "modeling and analysis of k tier downlink heterogeneous cellular networks"

Connected through hyperedge HE-3 (induced by source paper "effects of base station spatial interdependence on interference correlation and network performance"):
  with members:
    - "temporal correlation of interference and outage in mobile networks over one dimensional finite regions"
    - "spatio temporal interference correlation and joint coverage in cellular networks"
    - "network densification in 5g from the short range communications perspective"
    - "heterogeneous cellular networks with spatio temporal traffic delay analysis and scheduling"
    - "the intensity matching approach a tractable stochastic geometry approximation to system level analysis of cellular networks"
    - "cache enabled heterogeneous cellular networks optimal tier level content placement"
    - "analysis of interference correlation in non poisson networks"
    - "optimizing user association and spectrum allocation in hetnets a utility perspective"

Connected through hyperedge HE-4 (induced by source paper "coverage analysis of two tier hetnets for co channel orthogonal and partial spectrum sharing under fractional load conditions"):
  with members:
    - "fundamentals of cluster centric content placement in cache enabled device to device networks"
    - "modeling and performance analysis of clustered device to device networks"
    - "tier association probability and spectrum partitioning for maximum rate coverage in multi tier heterogeneous networks"
    - "fundamentals of throughput maximization with random arrivals for m2m communications"
    - "multi channel hybrid access femtocells a stochastic geometric analysis"
    - "average rate of downlink heterogeneous cellular networks over generalized fading channels a stochastic geometry approach"
    - "downlink rate distribution in heterogeneous cellular networks under generalized cell selection"
    - "offloading in heterogeneous networks modeling analysis and design insights"

Connected through hyperedge HE-5 (induced by source paper "analytical coverage probability of a typical user in heterogeneous cellular networks"):
  with members:
    - "sinr based k coverage probability in cellular networks with arbitrary shadowing"
    - "heterogeneous cellular networks with flexible cell association a comprehensive downlink sinr analysis"
    - "modeling and analysis of k tier downlink heterogeneous cellular networks"
    - "analytical evaluation of fractional frequency reuse for ofdma cellular networks"

Connected through hyperedge HE-6 (induced by source paper "optimizing user association and spectrum allocation in hetnets a utility perspective"):
  with members:
    - "on stochastic geometry modeling of cellular uplink transmission with truncated channel inversion power control"
    - "distributed pricing based user association for downlink heterogeneous cellular networks"
    - "tier association probability and spectrum partitioning for maximum rate coverage in multi tier heterogeneous networks"
    - "downlink and uplink decoupling a disruptive architectural design for 5g networks"
    - "modeling analysis and design for carrier aggregation in heterogeneous cellular networks"
    - "analysis of a proportionally fair and locally adaptive spatial aloha in poisson networks"
    - "joint access point selection and power allocation for uplink wireless networks"
    - "downlink mimo hetnets modeling ordering results and performance analysis"

Connected through hyperedge HE-7 (induced by source paper "handoff rate and coverage analysis in multi tier heterogeneous networks"):
  with members:
    - "tier association probability and spectrum partitioning for maximum rate coverage in multi tier heterogeneous networks"
    - "joint resource partitioning and offloading in heterogeneous cellular networks"
    - "downlink rate distribution in heterogeneous cellular networks under generalized cell selection"
    - "offloading in heterogeneous networks modeling analysis and design insights"
    - "towards understanding the fundamentals of mobility in cellular networks"
    - "heterogeneous cellular networks with flexible cell association a comprehensive downlink sinr analysis"
    - "modeling heterogeneous network interference using poisson point processes"
    - "modeling and analysis of k tier downlink heterogeneous cellular networks"

Connected through hyperedge HE-8 (induced by source paper "correlations of interference and link successes in heterogeneous cellular networks"):
  with members:
    - "managing interference correlation through random medium access"
    - "effect of spatial interference correlation on the performance of maximum ratio combining"
    - "diversity polynomials for the analysis of temporal correlations in wireless networks"
    - "offloading in heterogeneous networks modeling analysis and design insights"
    - "load aware modeling and analysis of heterogeneous cellular networks"
    - "heterogeneous cellular networks with flexible cell association a comprehensive downlink sinr analysis"
    - "diversity loss due to interference correlation"
    - "spatial and temporal correlation of the interference in aloha ad hoc 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.NI(Networking and Internet Architecture)