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: "phase noise influence in coherent optical ofdm systems with rf pilot tone digital ifft multiplexing and fft demodulation"
  Abstract: We present a comparative study of the influence of dispersion induced phase noise for CO-OFDM systems using Tx channel multiplexing and Rx matched filter (analogue hardware based); and FFT multiplexing/IFFT demultiplexing techniques (software based). An RF carrier pilot tone is used to mitigate the phase noise influence. From the analysis, it appears that the phase noise influence for the two OFDM implementations is very similar. The software based system provides a method for a rigorous evaluation of the phase noise variance caused by Common Phase Error (CPE) and Inter-Carrier Interference (ICI) and this, in turns, leads to a BER specification. Numerical results focus on a CO-OFDM system with 1GS/s QPSK channel modulation. Worst case BER results are evaluated and compared to the BER of a QPSK system with the same capacity as the OFDM implementation. Results are evaluated as a function of transmission distance, and for the QPSK system the influence of equalization enhanced phase noise (EEPN) is included. For both types of systems, the phase noise variance increases significantly with increasing transmission distance. An important and novel observation is that the two types of systems have very closely the same BER as a function of transmission distance for the same capacity. For the high capacity QPSK implementation, the increase in BER is due to EEPN, whereas for the OFDM approach it is due to the dispersion caused walk-off of the RF pilot tone relative to the OFDM signal channels. For a total capacity of 400 Gb/s, the transmission distance to have the BER < 10-4 is less than 277 km.

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"
    - "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:
    - "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"
    - "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"
    - "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"
    - "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"
    - "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"
    - "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"

Connected through hyperedge HE-5 (induced by source paper "comprehensive study of cd compensation and carrier phase estimation in optical communication systems 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"
    - "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-6 (induced by source paper "digital feed back carrier phase recovery in n psk coherent optical fiber systems"):
  with members:
    - "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 optical ofdm systems employing rf pilot tone for phase noise cancellation"

Connected through hyperedge HE-7 (induced by source paper "dynamic electronic dispersion equalization in coherent optical networks using variable step size least mean square algorithm"):
  with members:
    - "phase noise influence in long range coherent optical ofdm systems with delay detection ifft multiplexing and fft demodulation"
    - "analytical estimation in differential optical transmission systems influenced by equalization enhanced phase noise"
    - "phase noise influence in optical ofdm systems employing rf pilot tone for phase noise cancellation"

Connected through hyperedge HE-8 (induced by source paper "digital adaptive carrier phase estimation in multi level phase shift keying coherent optical communication systems"):
  with members:
    - "phase noise influence in long range coherent optical ofdm systems with delay detection ifft multiplexing and fft demodulation"
    - "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)