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: "per antenna constant envelope precoding for secure transmission in large scale miso systems"
  Abstract: Secure transmission in large-scale MISO systems employing artificial noise (AN) is studied under the per-antenna constant envelope (CE) constraint. Achievable secrecy rate of the per-antenna CE precoding scheme for large-scale MISO is analyzed and compared with that of the matched filter linear precoding. A two-stage per-antenna CE precoding scheme for joint signal-plus-AN transmission is proposed. The first stage determines the per-antenna CE precoding for the information-bearing signal. A properly generated AN using an iteration algorithm is incorporated into the transmit signal in the second stage such that the combined signal-plus-AN satisfies the per-antenna CE constraint and the AN is orthogonal to the user channel. It is shown that compared to conventional per-antenna CE transmission, this joint signal-plus-AN secure transmission scheme does not require additional transmit power. An alternative low-complexity AN generation scheme which uses a separate antenna to cancel the AN leakage to the intended user introduced by randomly generated AN is also proposed.

Connected through hyperedge HE-1 (induced by source paper "analysis and design of secure massive mimo systems in the presence of hardware impairments"):
  with members:
    - "secure massive mimo systems with limited rf chains"
    - "physical layer security for massive mimo systems impaired by phase noise"
    - "linear precoding of data and artificial noise in secure massive mimo systems"
    - "energy efficient power control a look at 5g wireless technologies"
    - "hardware impairments aware transceiver for full duplex massive mimo relaying"
    - "secure massive mimo transmission with an active eavesdropper"
    - "large scale mimo relaying techniques for physical layer security af or df"
    - "secret key agreement with large antenna arrays under the pilot contamination attack"

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)