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: "information theoretic analysis of mimo channel sounding"
  Abstract: The large majority of commercially available multiple-input multiple-output (MIMO) radio channel measurement devices (sounders) is based on time-division multiplexed switching (TDMS) of a single transmit/receive radio-frequency chain into the elements of a transmit/receive antenna array. While being cost-effective, such a solution can cause significant measurement errors due to phase noise and frequency offset in the local oscillators. In this paper, we systematically analyze the resulting errors and show that, in practice, overestimation of channel capacity by several hundred percent can occur. Overestimation is caused by phase noise (and to a lesser extent frequency offset) leading to an increase of the MIMO channel rank. Our analysis furthermore reveals that the impact of phase errors is, in general, most pronounced if the physical channel has low rank (typical for line-of-sight or poor scattering scenarios). The extreme case of a rank-1 physical channel is analyzed in detail. Finally, we present measurement results obtained from a commercially employed TDMS-based MIMO channel sounder. In the light of the findings of this paper, the results obtained through MIMO channel measurement campaigns using TDMS-based channel sounders should be interpreted with great care.

Connected through hyperedge HE-1 (induced by source paper "timing and carrier synchronization in wireless communication systems a survey and classification of research in the last 5 years"):
  with members:
    - "performance analysis of arbitrarily shaped underlay cognitive networks effects of secondary user activity protocols"
    - "directional cell discovery in millimeter wave cellular networks"
    - "training based synchronization and channel estimation in af two way relaying networks"
    - "improving bandwidth efficiency in e band communication systems"
    - "wireless networks with rf energy harvesting a contemporary survey"
    - "what will 5g be"
    - "channel phase noise and frequency offset in ofdm systems joint estimation data detection and hybrid cramer rao lower bound"
    - "time and frequency synchronization for multicarrier transmission on hexagonal time frequency lattice"

Connected through hyperedge HE-2 (induced by source paper "subspace estimation and decomposition for large millimeter wave mimo systems"):
  with members:
    - "subspace estimation and decomposition for hybrid analog digital millimetre wave mimo systems"
    - "channel estimation and hybrid precoding for millimeter wave cellular systems"
    - "spatially sparse precoding in millimeter wave mimo systems"
    - "millimeter wave beamforming for wireless backhaul and access in small cell networks"
    - "coding the beams improving beamforming training in mmwave communication system"

Connected through hyperedge HE-3 (induced by source paper "subspace estimation and decomposition for hybrid analog digital millimetre wave mimo systems"):
  with members:
    - "subspace estimation and decomposition for large millimeter wave mimo systems"
    - "channel estimation and hybrid precoding for millimeter wave cellular systems"
    - "spatially sparse precoding in millimeter wave mimo systems"

Connected through hyperedge HE-4 (induced by source paper "capacity bounds for mimo microwave backhaul links affected by phase noise"):
  with members:
    - "massive mimo systems with non ideal hardware energy efficiency estimation and capacity limits"
    - "multi sample receivers increase information rates for wiener phase noise channels"
    - "tight upper and lower bounds to the information rate of the phase noise channel"
    - "the papr problem in ofdm transmission new directions for a long lasting problem"
    - "on wiener phase noise channels at high signal to noise ratio"
    - "the capacity loss of dense constellations"

Connected through hyperedge HE-5 (induced by source paper "algorithms for joint phase estimation and decoding for mimo systems in the presence of phase noise"):
  with members:
    - "estimation of phase noise in oscillators with colored noise sources"
    - "soft metrics and their performance analysis for optimal data detection in the presence of strong oscillator phase noise"
    - "expectation propagation for approximate bayesian inference"

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)