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: "out of band radiation measure for mimo arrays with beamformed transmission"
  Abstract: The spatial characteristics of the out-of-band radiation that a multiuser MIMO system emits, due to its power amplifiers (modeled by a polynomial model) being nonlinear, are studied by deriving an analytical expression for the continuous-time cross-correlation of the transmit signals. It is shown that, at any spatial point and on any frequency, the received power averaged over many channel realizations from a MIMO base station is the same as from a SISO base station when the two radiate the same amount of power. For a specific channel realization however, the received power can deviate from this average. We show that the deviations from the average are small in a MIMO system with multiple users and that the deviations can be significant with only one user. Using an ergodicity argument, we conclude that out-of-band radiation is less of a problem in massive MIMO, where precoding and array gain let us reduce the total radiated power compared to SISO systems. The requirements on spectral regrowth can therefore be relaxed in MIMO systems without causing more total out-of-band radiation.

Connected through hyperedge HE-1 (induced by source paper "out of band radiation from antenna arrays clarified"):
  with members:
    - "impact of major rf impairments on mm wave communications using ofdm waveforms"
    - "analysis and design of secure massive mimo systems in the presence of hardware impairments"
    - "downlink mimo hcns with residual transceiver hardware impairments"
    - "impact of residual transmit rf impairments on training based mimo systems"
    - "massive mimo systems with non ideal hardware energy efficiency estimation and capacity limits"
    - "on the impact of hardware impairments on massive mimo"

Connected through hyperedge HE-2 (induced by source paper "on out of band emissions of quantized precoding in massive mu mimo ofdm"):
  with members:
    - "1 bit massive mu mimo precoding in vlsi"
    - "linear precoding with low resolution dacs for massive mu mimo ofdm downlink"
    - "massive mu mimo ofdm downlink with one bit dacs and linear precoding"
    - "analysis of one bit quantized precoding for the multiuser massive mimo downlink"
    - "downlink achievable rate analysis in massive mimo systems with one bit dacs"
    - "minimum ber precoding in 1 bit massive mimo systems"
    - "waveforms for the massive mimo downlink amplifier efficiency distortion and performance"
    - "quantized precoding for massive mu mimo"

Connected through hyperedge HE-3 (induced by source paper "spatial characteristics of distortion radiated from antenna arrays with transceiver nonlinearities"):
  with members:
    - "out of band radiation from large antenna arrays"
    - "reciprocity calibration for massive mimo proposal modeling and validation"
    - "massive mimo for next generation wireless systems"
    - "on the impact of hardware impairments on massive mimo"

Connected through hyperedge HE-4 (induced by source paper "impact of major rf impairments on mm wave communications using ofdm waveforms"):
  with members:
    - "on the impact of hardware impairments on massive mimo"
    - "five disruptive technology directions for 5g"

Connected through hyperedge HE-5 (induced by source paper "out of band radiation from large antenna arrays"):
  with members:
    - "massive mimo with non ideal arbitrary arrays hardware scaling laws and circuit aware design"
    - "on the impact of hardware impairments on massive mimo"
    - "five disruptive technology directions for 5g"
    - "constant envelope multi user precoding for frequency selective massive mimo 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)