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: "cooperation in 5g hetnets advanced spectrum access and d2d assisted communications"
  Abstract: The evolution of conventional wireless communication networks to the fifth generation (5G) is driven by an explosive increase in the number of wireless mobile devices and services, as well as their demand for all-time and everywhere connectivity, high data rates, low latency, high energy-efficiency and improved quality of service. To address these challenges, 5G relies on key technologies, such as full duplex (FD), device-to-device (D2D) communications, and network densification. In this article, a heterogeneous networking architecture is envisioned, where cells of different sizes and radio access technologies coexist. Specifically, collaboration for spectrum access is explored for both FD- and cognitive-based approaches, and cooperation among devices is discussed in the context of the state-of-the-art D2D assisted communication paradigm. The presented cooperative framework is expected to advance the understandings of the critical technical issues towards dynamic spectrum management for 5G heterogeneous networks.

Connected through hyperedge HE-1 (induced by source paper "non orthogonal multiple access noma how it meets 5g and beyond"):
  with members:
    - "securing downlink massive mimo noma networks with artificial noise"
    - "energy efficient joint user rb association and power allocation for uplink hybrid noma oma"
    - "capacity and outage analysis of a dual hop decode and forward relay aided noma scheme"
    - "energy efficient power allocation in uplink mmwave massive mimo with noma"
    - "optimal joint subcarrier and power allocation in noma is strongly np hard"
    - "power domain non orthogonal multiple access noma in 5g systems potentials and challenges"
    - "non orthogonal multiple access in large scale heterogeneous networks"
    - "a two phase power allocation scheme for crns employing noma"

Connected through hyperedge HE-2 (induced by source paper "joint caching and resource allocation in d2d assisted wireless hetnet"):
  with members:
    - "cache placement in two tier hetnets with limited storage capacity cache or buffer"
    - "inter cluster cooperation for wireless d2d caching networks"
    - "optimal caching and scheduling for cache enabled d2d communications"
    - "a delay aware caching algorithm for wireless d2d caching networks"
    - "wireless device to device caching networks basic principles and system performance"
    - "optimization and analysis of probabilistic caching in n tier heterogeneous networks"
    - "mode selection resource allocation and power control for d2d enabled two tier cellular network"
    - "analysis on cache enabled wireless heterogeneous networks"

Connected through hyperedge HE-3 (induced by source paper "generalized optimal two way relays subsets pairings in cloud based region cognitive networks"):
  with members:
    - "non orthogonal multiple access for cooperative communications challenges opportunities and trends"
    - "cognitive non orthogonal multiple access with cooperative relaying a new wireless frontier for 5g spectrum sharing"
    - "resource allocation and outage analysis for an adaptive cognitive two way relay network"
    - "performance of adaptive link selection with buffer aided relays in underlay cognitive networks"
    - "optimal relay selection for the parallel hybrid rf fso relay channel non buffer aided and buffer aided designs"
    - "separation framework an enabler for cooperative and d2d communication for future 5g networks"
    - "relay subset selection in wireless networks using partial decode and forward transmission"

Connected through hyperedge HE-4 (induced by source paper "all technologies work together for good a glance to future mobile networks"):
  with members:
    - "when mmwave communications meet network densification a scalable interference coordination perspective"
    - "power domain non orthogonal multiple access noma in 5g systems potentials and challenges"
    - "capacity comparison between mimo noma and mimo oma with multiple users in a cluster"
    - "optimal joint power and subcarrier allocation for full duplex multicarrier non orthogonal multiple access systems"
    - "massive mimo enabled full duplex cellular networks"
    - "non orthogonal multiple access in multi cell networks theory performance and practical challenges"
    - "hybrid beamforming for massive mimo a survey"
    - "scaling up mimo opportunities and challenges with very large arrays"

Connected through hyperedge HE-5 (induced by source paper "a two phase power allocation scheme for crns employing noma"):
  with members:
    - "noma in 5g systems exciting possibilities for enhancing spectral efficiency"
    - "capacity comparison between mimo noma and mimo oma with multiple users in a cluster"
    - "fairness for non orthogonal multiple access in 5g systems"
    - "a general mimo framework for noma downlink and uplink transmission based on signal alignment"

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)