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: "multiple input multiple output gaussian broadcast channels with common and confidential messages"
  Abstract: This paper considers the problem of the multiple-input multiple-output (MIMO) Gaussian broadcast channel with two receivers (receivers 1 and 2) and two messages: a common message intended for both receivers and a confidential message intended only for receiver 1 but needing to be kept asymptotically perfectly secure from receiver 2. A matrix characterization of the secrecy capacity region is established via a channel enhancement argument. The enhanced channel is constructed by first splitting receiver 1 into two virtual receivers and then enhancing only the virtual receiver that decodes the confidential message. The secrecy capacity region of the enhanced channel is characterized using an extremal entropy inequality previously established for characterizing the capacity region of a degraded compound MIMO Gaussian broadcast channel.

Connected through hyperedge HE-1 (induced by source paper "vector gaussian successive refinement with degraded side information"):
  with members:
    - "the sum rate of vector gaussian multiple description coding with tree structured covariance distortion constraints"
    - "vector gaussian rate distortion with variable side information"
    - "broadcasting correlated vector gaussians"
    - "new results on multiple input multiple output broadcast channels with confidential messages"
    - "private broadcasting over independent parallel channels"
    - "information theoretic proofs of entropy power inequalities"
    - "secure lossy transmission of vector gaussian sources"
    - "capacity equivocation region of the gaussian mimo wiretap channel"

Connected through hyperedge HE-2 (induced by source paper "physical layer service integration in 5g potentials and challenges"):
  with members:
    - "fundamental green tradeoffs progresses challenges and impacts on 5g networks"
    - "an overview of sustainable green 5g networks"
    - "gsvd based precoding in mimo systems with integrated services"
    - "robust artificial noise aided transmit design for multi user miso systems with integrated services"
    - "wireless powered communication opportunities and challenges"
    - "multi antenna relay aided wireless physical layer security"
    - "enhancing wireless information and power transfer by exploiting multi antenna techniques"
    - "simultaneous wireless information and power transfer in modern communication systems"

Connected through hyperedge HE-3 (induced by source paper "artificial noise aided biobjective transmitter optimization for service integration in multi user mimo broadcast channel"):
  with members:
    - "gsvd based precoding in mimo systems with integrated services"
    - "robust artificial noise aided transmit design for multi user miso systems with integrated services"
    - "what will 5g be"
    - "principles of physical layer security in multiuser wireless networks a survey"
    - "physical layer multicasting by stochastic transmit beamforming and alamouti space time coding"
    - "spatially selective artificial noise aided transmit optimization for miso multi eves secrecy rate maximization"
    - "wireless physical layer security with imperfect channel state information a survey"
    - "new results on multiple input multiple output broadcast channels with confidential messages"

Connected through hyperedge HE-4 (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-5 (induced by source paper "mimo gaussian broadcast channels with common private and confidential messages"):
  with members:
    - "broadcast channels with privacy leakage constraints"
    - "the capacity region of the two receiver vector gaussian broadcast channel with private and common messages"
    - "multi receiver wiretap channel with public and confidential messages"
    - "capacity region of gaussian mimo broadcast channels with common and confidential messages"
    - "the secrecy capacity region of the gaussian mimo multi receiver wiretap channel"
    - "towards the secrecy capacity of the gaussian mimo wire tap channel the 2 2 1 channel"
    - "the secrecy capacity of the mimo wiretap channel"

Connected through hyperedge HE-6 (induced by source paper "gsvd based precoding in mimo systems with integrated services"):
  with members:
    - "capacity region of gaussian mimo broadcast channels with common and confidential messages"
    - "secure transmission with multiple antennas ii the mimome wiretap channel"

Connected through hyperedge HE-7 (induced by source paper "transmitter optimization in miso broadcast channel with common and secret messages"):
  with members:
    - "spatially selective artificial noise aided transmit optimization for miso multi eves secrecy rate maximization"
    - "new results on multiple input multiple output broadcast channels with confidential messages"
    - "robust secure transmission in miso channels based on worst case optimization"
    - "capacity region of gaussian mimo broadcast channels with common and confidential messages"
    - "on ergodic secrecy capacity for gaussian miso wiretap channels"
    - "secure transmission with multiple antennas ii the mimome wiretap channel"
    - "the secrecy capacity of the mimo wiretap channel"
    - "on the secrecy capacity of fading channels"

Connected through hyperedge HE-8 (induced by source paper "on the secrecy capacity region of parallel broadcast channel with common and confidential messages"):
  with members:
    - "principles of physical layer security in multiuser wireless networks a survey"
    - "new results on multiple input multiple output broadcast channels with confidential messages"
    - "capacity region of gaussian mimo broadcast channels with common and confidential messages"
    - "the secrecy capacity region of the gaussian mimo multi receiver wiretap channel"
    - "capacity bounds for broadcast channels with confidential messages"
    - "the secrecy capacity of the mimo wiretap channel"

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)