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: "imbalanced beamforming by a multi antenna source for secure utilization of an untrusted relay"
  Abstract: We investigate a relay network where a multi-antenna source can potentially utilize an unauthenticated (untrusted) relay to augment its direct transmission of a confidential message to the destination. Since the relay is untrusted, it is desirable to protect the confidential data from it while simultaneously making use of it to increase the reliability of the transmission. We present a low-complexity scheme denoted as imbalanced beamforming based on linear beamforming and constellation mapping that ensures perfect physical-layer security even while utilizing the untrusted relay. Furthermore, the security of the scheme holds even if the relay adopts the conventional decode-and-forward protocol, unlike prior work. Simulation results show that the proposed imbalanced signaling maintains a constant BER of 0.5 at the eavesdropper at any SNR and number of source antennas, while maintaining or improving the detection performance of the destination compared to not utilizing the relay or existing security methods.

Connected through hyperedge HE-1 (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"
    - "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"
    - "solutions for the mimo gaussian wiretap channel with a cooperative jammer"
    - "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)