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: "jamming detection in massive mimo systems"
  Abstract: This paper considers the physical layer security of a pilot-based massive multiple-input multiple-output (MaMIMO) system in presence of a multi-antenna jammer. To improve security of the network, we propose a new jamming detection method that makes use of a generalized likelihood ratio test over some coherence blocks. Our proposed method utilizes intentionally unused pilots in the network. The performance of the proposed detector improves by increasing the number of antennas at the base station, the number of unused pilots and also by the number of the coherence blocks that are utilized. Simulation results confirm our analyses and show that in the MaMIMO regime, perfect detection (i.e., correct detection probability is one) is achievable even with a small number of unused pilots.

Connected through hyperedge HE-1 (induced by source paper "jamming robust uplink transmission for spatially correlated massive mimo systems"):
  with members:
    - "jamming suppression in massive mimo systems"
    - "hardware distortion correlation has negligible impact on ul massive mimo spectral efficiency"
    - "cell free massive mimo networks optimal power control against active eavesdropping"
    - "multiple antennas secure transmission under pilot spoofing and jamming attack"
    - "subverting massive mimo by smart jamming"
    - "secure massive mimo transmission with an active eavesdropper"
    - "physical layer security for massive mimo an overview on passive eavesdropping and active attacks"
    - "securing massive mimo at the physical layer"

Connected through hyperedge HE-2 (induced by source paper "jamming suppression in massive mimo systems"):
  with members:
    - "efficient dsp and circuit architectures for massive mimo state of the art and future directions"
    - "multiple antennas secure transmission under pilot spoofing and jamming attack"
    - "securing massive mimo at the physical layer"
    - "energy and spectral efficiency of very large multiuser mimo systems"

Connected through hyperedge HE-3 (induced by source paper "security vulnerability of fdd massive mimo systems in downlink training phase"):
  with members:
    - "a survey of physical layer security techniques for 5g wireless networks and challenges ahead"
    - "jamming resistant receivers for the massive mimo uplink"
    - "joint channel training and feedback for fdd massive mimo systems"
    - "structured compressive sensing based spatio temporal joint channel estimation for fdd massive mimo"
    - "low rank covariance assisted downlink training and channel estimation for fdd massive mimo systems"
    - "subverting massive mimo by smart jamming"
    - "secure massive mimo transmission with an active eavesdropper"
    - "physical layer security for massive mimo an overview on passive eavesdropping and active attacks"

Connected through hyperedge HE-4 (induced by source paper "multiple antennas secure transmission under pilot spoofing and jamming attack"):
  with members:
    - "secure transmission with large numbers of antennas and finite alphabet inputs"
    - "linear precoding of data and artificial noise in secure massive mimo systems"
    - "physical layer security in heterogeneous cellular networks"
    - "massive mimo pilot retransmission strategies for robustification against jamming"
    - "subverting massive mimo by smart jamming"
    - "secure massive mimo transmission with an active eavesdropper"
    - "pilot reuse for massive mimo transmission over spatially correlated rayleigh fading channels"
    - "securing massive mimo at the physical layer"

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.IT(Information Theory)