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: "solutions for the mimo gaussian wiretap channel with a cooperative jammer"
  Abstract: We study the Gaussian MIMO wiretap channel with a transmitter, a legitimate receiver, an eavesdropper and an external helper, each equipped with multiple antennas. The transmitter sends confidential messages to its intended receiver, while the helper transmits jamming signals independent of the source message to confuse the eavesdropper. The jamming signal is assumed to be treated as noise at both the intended receiver and the eavesdropper. We obtain a closed-form expression for the structure of the artificial noise covariance matrix that guarantees a secrecy rate larger or at least equal to the secrecy capacity of the wiretap channel with no jamming signal. We also describe how to find specific realizations of this covariance matrix expression that provide good secrecy rate performance, even when there is no nontrivial null space between the helper and the intended receiver. Unlike prior work, our approach considers the general MIMO case, and is not restricted to SISO or MISO scenarios.

Connected through hyperedge HE-1 (induced by source paper "multi antenna jamming in covert communication"):
  with members:
    - "achieving covert wireless communications using a full duplex receiver"
    - "fundamental limits of covert communication over mimo awgn channel"
    - "fundamental limits of communication with low probability of detection"
    - "covert communication in the presence of an uninformed jammer"
    - "covert communication over noisy channels a resolvability perspective"
    - "reliable deniable communication hiding messages in noise"
    - "limits of reliable communication with low probability of detection on awgn channels"
    - "cooperative jamming for secure communications in mimo relay networks"

Connected through hyperedge HE-2 (induced by source paper "a survey of physical layer security techniques for 5g wireless networks and challenges ahead"):
  with members:
    - "secure massive mimo systems with limited rf chains"
    - "secure transmission with large numbers of antennas and finite alphabet inputs"
    - "probabilistically robust swipt for secrecy misome systems"
    - "exploiting full duplex receivers for achieving secret communications in multiuser miso networks"
    - "full duplex bidirectional secure communications under perfect and distributionally ambiguous eavesdropper s csi"
    - "safeguarding decentralized wireless networks using full duplex jamming receivers"
    - "physical layer security aware routing and performance tradeoffs in ad hoc networks"
    - "hybrid procoder and combiner design for secure transmission in mmwave mimo systems"

Connected through hyperedge HE-3 (induced by source paper "mimo secret communications against an active eavesdropper"):
  with members:
    - "secure degrees of freedom regions of multiple access and interference channels the polytope structure"
    - "linear precoding of data and artificial noise in secure massive mimo systems"
    - "improving wireless physical layer security via exploiting co channel interference"
    - "secure massive mimo transmission with an active eavesdropper"
    - "physical layer security for massive mimo an overview on passive eavesdropping and active attacks"
    - "secure massive mimo transmission in the presence of an active eavesdropper"
    - "secure degrees of freedom of one hop wireless networks"
    - "improving physical layer secrecy using full duplex jamming receivers"

Connected through hyperedge HE-4 (induced by source paper "improving wireless physical layer security via exploiting co channel interference"):
  with members:
    - "joint power control in wiretap interference channels"
    - "secrecy transmit beamforming for heterogeneous networks"
    - "improving physical layer secrecy using full duplex jamming receivers"
    - "mobile jammers for secrecy rate maximization in cooperative networks"
    - "secure degrees of freedom of k user gaussian interference channels a unified view"
    - "multiuser diversity for secrecy communications using opportunistic jammer selection secure dof and jammer scaling law"
    - "mimo interference alignment over correlated channels with imperfect csi"
    - "interference alignment for secrecy"

Connected through hyperedge HE-5 (induced by source paper "secure communication through wireless powered friendly jamming jointly online optimization over geography energy and time"):
  with members:
    - "secrecy wireless information and power transfer in fading wiretap channel"
    - "wireless powered communication opportunities and challenges"
    - "wireless powered relays in cooperative communications time switching relaying protocols and throughput analysis"
    - "robust beamforming for secure communication in systems with wireless information and power transfer"
    - "secrecy wireless information and power transfer with miso beamforming"
    - "principles of physical layer security in multiuser wireless networks a survey"
    - "secure communication with a wireless powered friendly jammer"
    - "throughput maximization in wireless powered communication networks"

Connected through hyperedge HE-6 (induced by source paper "robust artificial noise aided transmit design for multi user miso systems with integrated services"):
  with members:
    - "safeguarding decentralized wireless networks using full duplex jamming receivers"
    - "principles of physical layer security in multiuser wireless networks a survey"
    - "physical layer multicasting by stochastic transmit beamforming and alamouti space time coding"
    - "wireless physical layer security with imperfect channel state information a survey"
    - "outage constrained robust secure transmission for miso wiretap channels"
    - "new results on multiple input multiple output broadcast channels with confidential messages"
    - "precoder design for physical layer multicasting"
    - "robust secure transmission in miso channels based on worst case optimization"

Connected through hyperedge HE-7 (induced by source paper "linear precoder design for a mimo gaussian wiretap channel with full duplex source and destination nodes"):
  with members:
    - "improving wireless physical layer security via exploiting co channel interference"
    - "joint power control in wiretap interference channels"
    - "secrecy transmit beamforming for heterogeneous networks"
    - "resource allocation in full duplex communications for future wireless networks"
    - "improving physical layer secrecy using full duplex jamming receivers"
    - "in band full duplex wireless challenges and opportunities"
    - "mimo interference alignment over correlated channels with imperfect csi"
    - "interference alignment for secrecy"

Connected through hyperedge HE-8 (induced by source paper "apply artificial noise to secure fading relay networks a ser based approach"):
  with members:
    - "secure communication via an untrusted non regenerative relay in fading channels"
    - "imbalanced beamforming by a multi antenna source for secure utilization of an untrusted relay"
    - "jamming games in the mimo wiretap channel with an active eavesdropper"
    - "new results on multiple input multiple output broadcast channels with confidential messages"
    - "secrecy sum rates for multi user mimo regularized channel inversion precoding"
    - "a tutorial on the optimization of amplify and forward mimo relay systems"
    - "physical layer network coding tutorial survey and beyond"
    - "secure transmission with artificial noise over fading channels achievable rate and optimal power allocation"

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)