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: "mu mimo mac protocols for wireless local area networks a survey"
  Abstract: As wireless devices boom and bandwidth-hungry applications (e.g., video and cloud uploading) get popular, today's wireless local area networks (WLANs) become not only crowded but also stressed at throughput. Multiuser multiple-input–multiple-output (MU-MIMO), an advanced form of MIMO, has gained attention due to its huge potential in improving the performance of WLANs. This paper surveys random access-based medium access control (MAC) protocols for MU-MIMO-enabled WLANs. It first provides background information about the evolution and the fundamental MAC schemes of IEEE 802.11 Standards and Amendments, and then identifies the key requirements of designing MU-MIMO MAC protocols for WLANs. After this, the most representative MU-MIMO MAC proposals in the literature are overviewed by benchmarking their MAC procedures and examining the key components, such as the channel state information acquisition, decoding/precoding, and scheduling schemes. Classifications and discussions on important findings of the surveyed MAC protocols are provided, based on which, the research challenges for designing effective MU-MIMO MAC protocols, as well as the envisaged MAC's role in the future heterogeneous networks, are highlighted.

Connected through hyperedge HE-1 (induced by source paper "spatial reuse in ieee 802 11ax wlans"):
  with members:
    - "potential and pitfalls of multi armed bandits for decentralized spatial reuse in wlans"
    - "to overlap or not to overlap enabling channel bonding in high density wlans"
    - "komondor a wireless network simulator for next generation high density wlans"
    - "dynamic channel bonding in spatially distributed high density wlans"
    - "survey and performance evaluation of the upcoming next generation wlan standard ieee 802 11ax"
    - "optimal resource allocation in ieee 802 11ax uplink ofdma with scheduled access"
    - "collaborative spatial reuse in wireless networks via selfish multi armed bandits"
    - "effective static and adaptive carrier sensing for dense wireless csma networks"

Connected through hyperedge HE-2 (induced by source paper "gaussian message passing for overloaded massive mimo noma"):
  with members:
    - "convergence analysis and assurance for gaussian message passing iterative detector in massive mu mimo systems"
    - "capacity achieving iterative lmmse detection for mimo noma systems"
    - "gaussian message passing iterative detection for mimo noma systems with massive access"
    - "adaptive damping and mean removal for the generalized approximate message passing algorithm"
    - "a general mimo framework for noma downlink and uplink transmission based on signal alignment"
    - "s amp for non linear observation models"
    - "scaling up mimo opportunities and challenges with very large arrays"
    - "energy efficient sensing and communication of parallel gaussian sources"

Connected through hyperedge HE-3 (induced by source paper "survey and performance evaluation of the upcoming next generation wlan standard ieee 802 11ax"):
  with members:
    - "ieee 802 11ax high efficiency wlans"
    - "leader contention based user matching for 802 11 multiuser mimo networks"
    - "uplink contention based scma for 5g radio access"
    - "multi round contention in wireless lans with multipacket reception"

Connected through hyperedge HE-4 (induced by source paper "improving dl mu mimo performance in ieee 802 11ac networks through decoupled scheduling"):
  with members:
    - "proportional fair mu mimo in 802 11 wlans"
    - "exploiting hybrid channel information for downlink multi user mimo scheduling"
    - "on the performance of packet aggregation in ieee 802 11ac mu mimo wlans"

Connected through hyperedge HE-5 (induced by source paper "an overview on resource allocation techniques for multi user mimo systems"):
  with members:
    - "low complexity downlink user selection for massive mimo systems"
    - "alternating minimization algorithms for hybrid precoding in millimeter wave mimo systems"
    - "an overview of signal processing techniques for millimeter wave mimo systems"
    - "user association in 5g networks a survey and an outlook"
    - "cell free massive mimo versus small cells"
    - "on the number of rf chains and phase shifters and scheduling design with hybrid analog digital beamforming"
    - "hybrid digital and analog beamforming design for large scale antenna arrays"
    - "massive mimo ten myths and one critical question"

Connected through hyperedge HE-6 (induced by source paper "interference aware opportunistic random access in dense iot networks"):
  with members:
    - "opportunistic downlink interference alignment for multi cell mimo networks"
    - "massive machine type communications in 5g physical and mac layer solutions"
    - "opportunistic interference alignment for random access networks"
    - "maximum sum rate of slotted aloha with capture"
    - "coded slotted aloha a graph based method for uncoordinated multiple access"
    - "cooperative slotted aloha for multi base station systems"
    - "scalable synchronization and reciprocity calibration for distributed multiuser mimo"
    - "can one achieve multiuser diversity in uplink multi cell networks"

Connected through hyperedge HE-7 (induced by source paper "survey of spectrum sharing for inter technology coexistence"):
  with members:
    - "network slicing based 5g and future mobile networks mobility resource management and challenges"
    - "grant free radio access iot networks scalability analysis in coexistence scenarios"
    - "inter technology coexistence in a spectrum commons a case study of wi fi and lte in the 5 ghz unlicensed band"
    - "fair coexistence of scheduled and random access wireless networks unlicensed lte wifi"
    - "ieee 802 11ax high efficiency wlans"
    - "embedding lte u within wi fi bands for spectrum efficiency improvement"
    - "modeling and analyzing the coexistence of wi fi and lte in unlicensed spectrum"
    - "performance analysis of license assisted access lte with asymmetric hidden terminals"

Connected through hyperedge HE-8 (induced by source paper "ap initiated multi user transmissions in ieee 802 11ax wlans"):
  with members:
    - "performance analysis of dynamic channel bonding in spatially distributed high density wlans"
    - "a high efficiency mac protocol for wlans providing fairness in dense scenarios"
    - "ieee 802 11ax high efficiency wlans"
    - "collision free operation in high density wlan deployments"
    - "on the interactions between multiple overlapping wlans using channel bonding"
    - "resource management for ofdma based next generation 802 11 wlans"
    - "analysis of dynamic channel bonding in dense networks of wlans"

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)