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: "joint interference and user association optimization in cellular wireless networks"
  Abstract: In cellular wireless networks, user association refers to the problem of assigning mobile users to base station cells -- a critical, but challenging, problem in many emerging small cell and heterogeneous networks. This paper considers a general class of utility maximization problems for joint optimization of mobile user associations and bandwidth and power allocations. The formulation can incorporate a large class of network topologies, interference models, SNR-to-rate mappings and network constraints. In addition, the model can applied in carrier aggregation scenarios where mobiles can be served by multiple cells simultaneously. While the problem is non-convex, our main contribution shows that the optimization admits a separable dual decomposition. This property enables fast computation of upper bounds on the utility as well as an efficient, distributed implementation for approximate local optimization via augmented Lagrangian techniques. Simulations are presented in heterogeneous networks with mixtures of macro and picocells. We demonstrate significant value of the proposed methods in scenarios with variable backhaul capacity in the femtocell links and in cases where the user density is sufficiently low that lightly-used cells can reduce power.

Connected through hyperedge HE-1 (induced by source paper "hybrid spectrum sharing in mmwave cellular networks"):
  with members:
    - "stochastic geometric coverage analysis in mmwave cellular networks with a realistic channel model"
    - "resource sharing in 5g mmwave cellular networks"
    - "downlink and uplink cell association with traditional macrocells and millimeter wave small cells"
    - "spectrum and infrastructure sharing in millimeter wave cellular networks an economic perspective"
    - "understanding noise and interference regimes in 5g millimeter wave cellular networks"
    - "spectrum sharing in mmwave cellular networks via cell association coordination and beamforming"
    - "hybrid spectrum access for mmwave networks"
    - "gains of restricted secondary licensing in millimeter wave cellular systems"

Connected through hyperedge HE-2 (induced by source paper "backhaul aware user association and resource allocation for energy constrained hetnets"):
  with members:
    - "joint downlink cell association and bandwidth allocation for wireless backhauling in two tier hetnets with large scale antenna arrays"
    - "energy harvesting wireless communications a review of recent advances"
    - "5g wireless backhaul networks challenges and research advances"
    - "a traffic load balancing framework for software defined radio access networks powered by hybrid energy sources"
    - "an overview of load balancing in hetnets old myths and open problems"
    - "distributed pricing based user association for downlink heterogeneous cellular networks"
    - "unified and distributed qos driven cell association algorithms in heterogeneous networks"
    - "distributed resource allocation for relay aided device to device communication a message passing approach"

Connected through hyperedge HE-3 (induced by source paper "joint user association power control and scheduling in multi cell 5g networks"):
  with members:
    - "distributed pricing based user association for downlink heterogeneous cellular networks"

Connected through hyperedge HE-4 (induced by source paper "distributed pricing based user association for downlink heterogeneous cellular networks"):
  with members:
    - "user association for load balancing in heterogeneous cellular networks"
    - "mechanism design for base station association and resource allocation in downlink ofdma network"

Connected through hyperedge HE-5 (induced by source paper "opportunistic third party backhaul for cellular wireless networks"):
  with members:
    - "user association for load balancing in heterogeneous cellular networks"
    - "femtocell networks a survey"

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)