human: Given a hyperedge-centered hypergraph: <hypergraph>, where the center hyperedge is induced by one source paper and its member nodes are the cited papers.

Details of the hypergraph:
Center hyperedge (induced by source paper "digital feed back carrier phase recovery in n psk coherent optical fiber systems"):
  Abstract: The analysis of feed-back carrier phase recovery is investigated in long-haul high speed n-level phase shift keying (n-PSK) optical fiber communication systems based on the one-tap normalized least-mean-square algorithm. The close-form expressions for the estimated carrier phase and the bit-error-rate floor have been derived in the n-level phase shift keying coherent optical transmission systems. The results show that the one-tap normalized least-mean-square algorithm works well in the carrier phase recovery, but will be less effective with the increment of modulation level, in the compensation of both intrinsic laser phase noise and equalization enhanced phase noise.

Includes members:
  Member "analysis of chromatic dispersion compensation and carrier phase recovery in long haul optical transmission system influenced by equalization enhanced phase noise":
    also connected through other hyperedges:
      - Hyperedge HE-1 (induced by source paper "digital signal processing for optical communications and networks i linear compensation")
  Member "phase noise influence in long range coherent optical ofdm systems with delay detection ifft multiplexing and fft demodulation":
    also connected through other hyperedges:
      - Hyperedge HE-2 (induced by source paper "digital signal processing for optical communications and networks i linear compensation")
  Member "phase noise influence in coherent optical ofdm systems with rf pilot tone digital ifft multiplexing and fft demodulation":
    also connected through other hyperedges:
      - Hyperedge HE-3 (induced by source paper "digital signal processing for optical communications and networks i linear compensation")
  Member "phase noise influence in optical ofdm systems employing rf pilot tone for phase noise cancellation":
    also connected through other hyperedges:
      - Hyperedge HE-4 (induced by source paper "digital signal processing for optical communications and networks i linear compensation")

Question: Please tell me which class the source paper 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)