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: "analytical investigations on carrier phase recovery in dispersion unmanaged n psk coherent optical communication systems"
  Abstract: Using coherent optical detection and digital signal processing, laser phase noise and equalization enhanced phase noise can be effectively mitigated using the feed-forward and feed-back carrier phase recovery approaches. In this paper, theoretical analyses of feed-back and feed-forward carrier phase recovery methods have been carried out in the long-haul high-speed n-level phase shift keying (n-PSK) optical fiber communication systems, involving a one-tap normalized least-mean-square (LMS) algorithm, a block-wise average algorithm, and a Viterbi-Viterbi algorithm. The analytical expressions for evaluating the estimated carrier phase and for predicting the bit-error-rate (BER) performance (such as the BER floors) have been presented and discussed in the n-PSK coherent optical transmission systems by considering both the laser phase noise and the equalization enhanced phase noise. The results indicate that the Viterbi-Viterbi carrier phase recovery algorithm outperforms the one-tap normalized LMS and the block-wise average algorithms for small phase noise variance (or effective phase noise variance), while the one-tap normalized LMS algorithm shows a better performance than the other two algorithms for large phase noise variance (or effective phase noise variance). In addition, the one-tap normalized LMS algorithm is more sensitive to the level of modulation formats.

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"
    - "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"
    - "comparative study on carrier phase estimation methods in dispersion unmanaged optical transmission systems"

Connected through hyperedge HE-2 (induced by source paper "analysis of chromatic dispersion compensation and carrier phase recovery in long haul optical transmission system influenced by equalization enhanced phase noise"):
  with members:
    - "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"

Connected through hyperedge HE-3 (induced by source paper "comparative study on carrier phase estimation methods in dispersion unmanaged optical transmission systems"):
  with members:
    - "achievable information rates estimates in optically amplified transmission systems using nonlinearity compensation and probabilistic shaping"
    - "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"
    - "channel coding the road to channel capacity"

Connected through hyperedge HE-4 (induced by source paper "carrier phase estimation in dispersion unmanaged optical transmission systems"):
  with members:
    - "achievable information rates estimates in optically amplified transmission systems using nonlinearity compensation and probabilistic shaping"
    - "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"

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)