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: "backhaul aware user association and resource allocation for energy constrained hetnets"
  Abstract: Growing attention has been paid to renewable- or hybrid-energy-powered heterogeneous networks (HetNets). In this paper, focusing on backhaul-aware joint user association and resource allocation for this type of HetNets, we formulate an online optimization problem to maximize the network utility reflecting proportional fairness. Since user association and resource allocation are tightly coupled not only on resource consumption of the base stations (BSs) but in the constraints of their available energy and backhaul as well, the closed-form solution is quite difficult to obtain. Thus, we solve the problem distributively by employing certain decomposition methods. Specifically, at first, by adopting the primal decomposition method, we decompose the original problem into a lower level resource-allocation problem for each BS and a higher level user-association problem. For the optimal resource allocation, we prove that a BS either assigns equal normalized resources or provides an equal long-term service rate to its served users. Then, the user-association problem is solved by the Lagrange dual decomposition method, and a completely distributed algorithm is developed. Moreover, applying results of the subgradient method, we demonstrate the convergence of the proposed distributed algorithm. Furthermore, to efficiently and reliably apply the proposed algorithm to the future wireless networks with an extremely dense BS deployment, we design a virtual user association and resource allocation scheme based on the software-defined networking architecture. Finally, numerical results validate the convergence of the proposed algorithm and the significant improvement on network utility, load balancing, and user fairness.

Connected through hyperedge HE-1 (induced by source paper "resource allocation and power control in cooperative small cell networks in frequency selective channels with backhaul constraint"):
  with members:
    - "tier aware resource allocation in ofdma macrocell small cell networks"
    - "sinr and throughput scaling in ultradense urban cellular networks"
    - "distributed pricing based user association for downlink heterogeneous cellular networks"
    - "optimal user cell association for massive mimo wireless networks"
    - "user association for load balancing in heterogeneous cellular networks"
    - "resource allocation for downlink cellular ofdma systems part ii practical algorithms and optimal reuse factor"
    - "resource allocation for downlink cellular ofdma systems part i optimal allocation"

Connected through hyperedge HE-2 (induced by source paper "learning oriented cross entropy approach to user association in load balanced hetnet"):
  with members:
    - "utility energy efficiency oriented user association with power control in heterogeneous networks"
    - "user association in 5g networks a survey and an outlook"
    - "distributed pricing based user association for downlink heterogeneous cellular networks"
    - "user association for load balancing in heterogeneous cellular networks"

Connected through hyperedge HE-3 (induced by source paper "energy efficient user association and power allocation in millimeter wave based ultra dense networks with energy harvesting base stations"):
  with members:
    - "distributed association and relaying with fairness in millimeter wave networks"
    - "energy efficient cell activation user association and spectrum allocation in heterogeneous networks"
    - "user association and interference management in massive mimo hetnets"
    - "efficient scheduling and power allocation for d2d assisted wireless caching networks"
    - "mmwave massive mimo based wireless backhaul for the 5g ultra dense network"
    - "matching theory for backhaul management in small cell networks with mmwave capabilities"
    - "downlink performance of cellular systems with base station sleeping user association and scheduling"
    - "an overview of load balancing in hetnets old myths and open problems"

Connected through hyperedge HE-4 (induced by source paper "joint spectrum allocation and structure optimization in green powered heterogeneous cognitive radio networks"):
  with members:
    - "toward hierarchical mobile edge computing an auction based profit maximization approach"
    - "wireless networks with energy harvesting and power transfer joint power and time allocation"
    - "optimal cooperative power allocation for energy harvesting enabled relay networks"
    - "joint spectrum and power allocation for multi node cooperative wireless systems"
    - "on green energy powered cognitive radio networks"
    - "qos aware base station selections for distributed mimo links in broadband wireless networks"
    - "maximizing system throughput by cooperative sensing in cognitive radio 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)