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: "on the performance of packet aggregation in ieee 802 11ac mu mimo wlans"
  Abstract: Multi-user spatial multiplexing combined with packet aggregation can significantly increase the performance of Wireless Local Area Networks (WLANs). In this letter, we present and evaluate a simple technique to perform packet aggregation in IEEE 802.11ac MU-MIMO (Multi-user Multiple Input Multiple Output) WLANs. Results show that in non-saturation conditions both the number of active stations (STAs) and the queue size have a significant impact on the system performance. If the number of stations is excessively high, the heterogeneity of destinations in the packets contained in the queue makes it difficult to take full advantage of packet aggregation. This effect can be alleviated by increasing the queue size, which increases the chances to schedule a large number of packets at each transmission, hence improving the system throughput at the cost of a higher delay.

Connected through hyperedge HE-1 (induced by source paper "improving dl mu mimo performance in ieee 802 11ac networks through decoupled scheduling"):
  with members:
    - "mu mimo mac protocols for wireless local area networks a survey"
    - "proportional fair mu mimo in 802 11 wlans"
    - "exploiting hybrid channel information for downlink multi user mimo scheduling"

Connected through hyperedge HE-2 (induced by source paper "coupled ieee 802 11ac and tcp goodput improvement using aggregation and reverse direction"):
  with members:
    - "a new aggregation based scheduling method for rapidly changing ieee 802 11ac wireless channels"

Connected through hyperedge HE-3 (induced by source paper "mu mimo mac protocols for wireless local area networks a survey"):
  with members:
    - "uni mumac a unified down up link mu mimo mac protocol for ieee 802 11ac wlans"
    - "leader contention based user matching for 802 11 multiuser mimo networks"
    - "proportional fair mu mimo in 802 11 wlans"
    - "massive mimo for next generation wireless systems"
    - "evolution toward 5g multi tier cellular wireless networks an interference management perspective"
    - "design and characterization of a full duplex multiantenna system for wifi networks"
    - "managing heterogeneous wsns in smart cities challenges and requirements"
    - "pushing the limits of full duplex design and real time implementation"

Connected through hyperedge HE-4 (induced by source paper "uni mumac a unified down up link mu mimo mac protocol for ieee 802 11ac wlans"):
  with members:
    - "on the distributed construction of a collision free schedule in multi hop packet radio networks"
    - "multi round contention in wireless lans with multipacket reception"

Connected through hyperedge HE-5 (induced by source paper "proportional fair mu mimo in 802 11 wlans"):
  with members:
    - "convexity conditions for 802 11 wlans"
    - "max min fairness in 802 11 mesh networks"

Connected through hyperedge HE-6 (induced by source paper "performance analysis of a multiuser multi packet transmission system for wlans in non saturation conditions"):
  with members:
    - "performance analysis of csma ca protocols with multi packet transmission"

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)