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: "unified and distributed qos driven cell association algorithms in heterogeneous networks"
  Abstract: This paper addresses the cell association problem in the downlink of a multi-tier heterogeneous network (HetNet), where base stations (BSs) have finite number of resource blocks (RBs) available to distribute among their associated users. Two problems are defined and treated in this paper: sum utility of long term rate maximization with long term rate quality of service (QoS) constraints, and global outage probability minimization with outage QoS constraints. The first problem is well-suited for low mobility environments, while the second problem provides a framework to deal with environments with fast fading. The defined optimization problems in this paper are solved in two phases: cell association phase followed by the optional RB distribution phase. We show that the cell association phase of both problems have the same structure. Based on this similarity, we propose a unified distributed algorithm with low levels of message passing to for the cell association phase. This distributed algorithm is derived by relaxing the association constraints and using Lagrange dual decomposition method. In the RB distribution phase, the remaining RBs after the cell association phase are distributed among the users. Simulation results show the superiority of our distributed cell association scheme compared to schemes that are based on maximum signal to interference plus noise ratio (SINR).

Connected through hyperedge HE-1 (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"
    - "distributed resource allocation for relay aided device to device communication a message passing approach"
    - "what will 5g be"

Connected through hyperedge HE-2 (induced by source paper "association and load optimization with user priorities in load coupled heterogeneous networks"):
  with members:
    - "load optimization with user association in cooperative and load coupled lte networks"
    - "power and load coupling in cellular networks for energy optimization"
    - "distributed pricing based user association for downlink heterogeneous cellular networks"
    - "what will 5g be"
    - "analysis of cell load coupling for lte network planning and optimization"
    - "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 "distributed association and relaying with fairness in millimeter wave networks"):
  with members:
    - "beam searching and transmission scheduling in millimeter wave communications"
    - "millimeter wave cellular networks a mac layer perspective"
    - "the transitional behavior of interference in millimeter wave networks and its impact on medium access control"
    - "an overview of load balancing in hetnets old myths and open problems"
    - "distributed pricing based user association for downlink heterogeneous cellular networks"
    - "what will 5g be"
    - "millimeter wave cellular wireless networks potentials and challenges"
    - "spatially sparse precoding in millimeter wave mimo systems"

Connected through hyperedge HE-4 (induced by source paper "joint downlink cell association and bandwidth allocation for wireless backhauling in two tier hetnets with large scale antenna arrays"):
  with members:
    - "optimizing user association and spectrum allocation in hetnets a utility perspective"
    - "interference management in 5g reverse tdd hetnets with wireless backhaul a large system analysis"
    - "an overview of load balancing in hetnets old myths and open problems"
    - "wireless backhaul networks capacity bound scalability analysis and design guidelines"
    - "what will 5g be"
    - "massive mimo meets hetnet interference coordination through spatial blanking"
    - "evolution toward 5g multi tier cellular wireless networks an interference management perspective"
    - "five disruptive technology directions for 5g"

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)