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: "exploiting device to device communications to enhance spatial reuse for popular content downloading in directional mmwave small cells"
  Abstract: With the explosive growth of mobile demand, small cells in millimeter-wave (mmWave) bands underlying macrocell networks have attracted intense interest from both academia and industry. MmWave communications in the 60-GHz band are able to utilize the huge unlicensed bandwidth to provide multiple Gb/s transmission rates. In this case, device-to-device (D2D) communications in mmWave bands should be fully exploited because there is no interference with the macrocell networks and higher achievable transmission rates. In addition, because there is less interference by directional transmission, multiple links including D2D links can be scheduled for concurrent transmissions (spatial reuse). With the popularity of content-based mobile applications, popular content downloading in the small cells needs to be optimized to improve network performance and enhance user experience. In this paper, we develop an efficient scheduling scheme for popular content downloading in mmWave small cells called popular content downloading scheduling (PCDS), where both D2D communications in close proximity and concurrent transmissions are exploited to improve transmission efficiency. In PCDS, a transmission path selection algorithm is designed to establish multihop transmission paths for users, aiming at better utilization of D2D communications and concurrent transmissions. After transmission path selection, a concurrent transmission scheduling algorithm is designed to maximize the spatial reuse gain. Through extensive simulations under various traffic patterns, we demonstrate that PCDS achieves near-optimal performance in terms of delay and throughput, as well as superior performance, compared with other existing protocols, particularly under heavy load. The impact of the maximum number of hops of transmission paths on its performance is also analyzed for a better understanding of the role of D2D communications.

Connected through hyperedge HE-1 (induced by source paper "device to device communications enabled multicast scheduling with the multi level codebook in mmwave small cells"):
  with members:
    - "energy efficient user association and power allocation in millimeter wave based ultra dense networks with energy harvesting base stations"
    - "joint power allocation and beamforming for non orthogonal multiple access noma in 5g millimeter wave communications"
    - "hierarchical codebook design for beamforming training in millimeter wave communication"
    - "millimeter wave vehicular communication to support massive automotive sensing"
    - "enabling uav cellular with millimeter wave communication potentials and approaches"
    - "exploiting device to device communications in joint scheduling of access and backhaul for mmwave small cells"
    - "femtocell networks a survey"

Connected through hyperedge HE-2 (induced by source paper "device to device communication in cellular networks"):
  with members:
    - "energy efficient joint resource allocation and power control for d2d communications"
    - "a survey on device to device communication in cellular networks"
    - "cognitive and energy harvesting based d2d communication in cellular networks stochastic geometry modeling and analysis"
    - "low rate machine type communication via wireless device to device d2d links"
    - "base station assisted device to device communications for high throughput wireless video networks"
    - "power control for d2d underlaid cellular networks modeling algorithms and analysis"

Connected through hyperedge HE-3 (induced by source paper "optimal relay probing in millimeter wave cellular systems with device to device relaying"):
  with members:
    - "spectrum sharing for device to device communication in cellular networks"
    - "connectivity of millimeter wave networks with multi hop relaying"
    - "an overview of load balancing in hetnets old myths and open problems"
    - "tractable model for rate in self backhauled millimeter wave cellular networks"
    - "coverage and rate analysis for millimeter wave cellular networks"
    - "what will 5g be"
    - "millimeter wave cellular wireless networks potentials and challenges"
    - "millimeter wave beamforming for wireless backhaul and access in small cell 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)