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: "coding the beams improving beamforming training in mmwave communication system"
  Abstract: The mmWave communication system is operating at a regime with high number of antennas and very limited number of RF analog chains. Large number of antennas are used to extend the communication range for recovering the high path loss while fewer RF analog chains are designed to reduce transmit and processing power and hardware complexity. In this regime, typical MIMO algorithms are not applicable. #R##N#Before any communication starts, devices are needed to align their beam pointing angles towards each other. An efficient searching protocol to obtain the best beam angle pair is therefore needed. It is called BeamForming (BF) training protocol. #R##N#This paper presents a new BF training technique called beam coding. Each beam angle is assigned unique signature code. By coding multiple beam angles and steering at their angles simultaneously in a training packet, the best beam angle pair can be obtained in a few packets. The proposed BF training technique not only shows the robustness in non-line-of-sight environment, but also provides very flat power variations within a packet in contrast to the IEEE 802.11ad standard whose scheme may lead to large dynamic range of signals due to beam angles varying across a training packet.

Connected through hyperedge HE-1 (induced by source paper "sub channel allocation for device to device underlaying full duplex mmwave small cells using coalition formation games"):
  with members:
    - "on low resolution adcs in practical 5g millimeter wave massive mimo systems"
    - "full duplex amplify and forward relaying power and location optimization"
    - "joint power allocation and beamforming for non orthogonal multiple access noma in 5g millimeter wave communications"
    - "full duplex millimeter wave communication"
    - "game theoretic dynamic channel allocation for frequency selective interference channels"
    - "leveraging social communities for optimizing cellular device to device communications"
    - "on the spectral efficiency of massive mimo systems with low resolution adcs"
    - "exploiting device to device communications in joint scheduling of access and backhaul for mmwave small cells"

Connected through hyperedge HE-2 (induced by source paper "energy efficient power control of train ground mmwave communication for high speed trains"):
  with members:
    - "device to device communications enabled energy efficient multicast scheduling in mmwave small cells"
    - "ultra reliable communication in 5g mmwave networks a risk sensitive approach"
    - "positioning of high speed trains using 5g new radio synchronization signals"
    - "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"
    - "boosting spatial reuse via multiple path multihop scheduling for directional mmwave wpans"
    - "millimeter wave cellular wireless networks potentials and challenges"

Connected through hyperedge HE-3 (induced by source paper "performance analysis of directional modulation with finite quantized rf phase shifters in analog beamforming structure"):
  with members:
    - "robust secure transmission of using main lobe integration based leakage beamforming in directional modulation mu mimo systems"
    - "artificial noise aided secure multicast precoding for directional modulation systems"
    - "channel estimation and hybrid precoding for millimeter wave cellular systems"
    - "spatially sparse precoding in millimeter wave mimo systems"
    - "improving physical layer secrecy using full duplex jamming receivers"
    - "millimeter wave beamforming for wireless backhaul and access in small cell networks"

Connected through hyperedge HE-4 (induced by source paper "tracking position and orientation through millimeter wave lens mimo in 5g systems"):
  with members:
    - "optimal precoders for tracking the aod and aoa of a mmwave path"
    - "direct localization for massive mimo"
    - "error bounds for uplink and downlink 3d localization in 5g mmwave systems"
    - "multi user millimeter wave mimo with full dimensional lens antenna array"
    - "compressive channel estimation and tracking for large arrays in mm wave picocells"
    - "joint device positioning and clock synchronization in 5g ultra dense networks"
    - "frequency selective hybrid precoding for limited feedback millimeter wave systems"
    - "tracking angles of departure and arrival in a mobile millimeter wave channel"

Connected through hyperedge HE-5 (induced by source paper "efficient beam training and channel estimation for millimeter wave communications under mobility"):
  with members:
    - "compressive channel estimation and tracking for large arrays in mm wave picocells"
    - "an overview of signal processing techniques for millimeter wave mimo systems"
    - "tracking mm wave channel dynamics fast beam training strategies under mobility"
    - "compressed sensing for wireless communications useful tips and tricks"
    - "tracking angles of departure and arrival in a mobile millimeter wave channel"
    - "a survey of millimeter wave mmwave communications for 5g opportunities and challenges"
    - "training beam sequence design for millimeter wave mimo systems a pomdp framework"
    - "channel estimation and hybrid precoding for millimeter wave cellular systems"

Connected through hyperedge HE-6 (induced by source paper "ieee 802 11ay based mmwave wlans design challenges and solutions"):
  with members:
    - "performance analysis of integrated sub 6 ghz millimeter wave wireless local area networks"
    - "beamspace su mimo for future millimeter wave wireless communications"
    - "ieee 802 11ax high efficiency wlans"
    - "initial access in 5g mmwave cellular networks"
    - "flexible dual connectivity spectrum aggregation for decoupled uplink and downlink access in 5g heterogeneous systems"
    - "joint millimeter wave and microwave resources allocation in cellular networks with dual mode base stations"
    - "reciprocity calibration for massive mimo proposal modeling and validation"
    - "beam searching and transmission scheduling in millimeter wave communications"

Connected through hyperedge HE-7 (induced by source paper "qos aware full duplex concurrent scheduling for millimeter wave wireless backhaul networks"):
  with members:
    - "full duplex amplify and forward relaying power and location optimization"
    - "full duplex millimeter wave communication"
    - "hierarchical codebook design for beamforming training in millimeter wave communication"
    - "exploiting device to device communications in joint scheduling of access and backhaul for mmwave small cells"
    - "a survey of millimeter wave mmwave communications for 5g opportunities and challenges"
    - "wireless backhaul node placement for small cell networks"
    - "in band full duplex wireless challenges and opportunities"

Connected through hyperedge HE-8 (induced by source paper "statistical location and rotation aware beam search for millimeter wave networks"):
  with members:
    - "improved handover through dual connectivity in 5g mmwave mobile networks"
    - "context information based initial cell search for millimeter wave 5g cellular networks"
    - "comparative analysis of initial access techniques in 5g mmwave cellular networks"
    - "context information for fast cell discovery in mm wave 5g networks"
    - "channel estimation and hybrid precoding for millimeter wave cellular systems"

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)