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: "comparative study on carrier phase estimation methods in dispersion unmanaged optical transmission systems"
  Abstract: The comparative study on three carrier phase estimation (CPE) methods, involving a one-tap normalized least-mean-square algorithm, a block-wise average algorithm, and a Viterbi-Viterbi algorithm has been carried out in the long-haul high-speed dispersion-unmanaged coherent optical transmission systems. The close-form predictions for bit-error-rate behaviors in these CPE methods have been analyzed by considering both the laser phase noise and the equalization enhanced phase noise.

Connected through hyperedge HE-1 (induced by source paper "digital signal processing for optical communications and networks i linear compensation"):
  with members:
    - "achievable information rates estimates in optically amplified transmission systems using nonlinearity compensation and probabilistic shaping"
    - "analysis of chromatic dispersion compensation and carrier phase recovery in long haul optical transmission system influenced by equalization enhanced phase noise"
    - "analytical investigations on carrier phase recovery in dispersion unmanaged n psk coherent optical communication systems"
    - "phase noise influence in long range coherent optical ofdm systems with delay detection ifft multiplexing and fft demodulation"
    - "phase noise influence in coherent optical ofdm systems with rf pilot tone digital ifft multiplexing and fft demodulation"
    - "analytical estimation in differential optical transmission systems influenced by equalization enhanced phase noise"
    - "digital adaptive carrier phase estimation in multi level phase shift keying coherent optical communication systems"
    - "phase noise influence in optical ofdm systems employing rf pilot tone for phase noise cancellation"

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)