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: "a feedback reduction technique for mimo broadcast channels"
  Abstract: A multiple antenna broadcast channel with perfect channel state information at the receivers is considered. If each receiver quantizes its channel knowledge to a finite number of bits which are fed back to the transmitter, the large capacity benefits of the downlink channel can be realized. However, the required number of feedback bits per mobile must be scaled with both the number of transmit antennas and the system SNR, and thus can be quite large in even moderately sized systems. It is shown that a small number of antennas can be used at each receiver to improve the quality of the channel estimate provided to the transmitter. As a result, the required feedback rate per mobile can be significantly decreased.

Connected through hyperedge HE-1 (induced by source paper "volume of metric balls in high dimensional complex grassmann manifolds"):
  with members:
    - "from random matrix theory to coding theory volume of a metric ball in unitary group"
    - "normalized volume of hyperball in complex grassmann manifold and its application in large scale mu mimo communication systems"
    - "multiuser diversity for secrecy communications using opportunistic jammer selection secure dof and jammer scaling law"
    - "quantization bounds on grassmann manifolds and applications to mimo communications"

Connected through hyperedge HE-2 (induced by source paper "tranceiver design using linear precoding in a multiuser mimo system with limited feedback"):
  with members:
    - "minimizing sum mse implies identical downlink and dual uplink power allocations"
    - "limited feedback based block diagonalization for the mimo broadcast channel"
    - "antenna combining for the mimo downlink channel"
    - "mimo broadcast channels with block diagonalization and finite rate feedback"
    - "mimo broadcast channels with finite rate feedback"

Connected through hyperedge HE-3 (induced by source paper "limited feedback based block diagonalization for the mimo broadcast channel"):
  with members:
    - "antenna combining for the mimo downlink channel"
    - "mimo broadcast channels with block diagonalization and finite rate feedback"
    - "mimo broadcast channels with finite rate feedback"
    - "quantization bounds on grassmann manifolds and applications to mimo communications"

Connected through hyperedge HE-4 (induced by source paper "antenna combining for the mimo downlink channel"):
  with members:
    - "limited feedback based block diagonalization for the mimo broadcast channel"
    - "quantized vs analog feedback for the mimo downlink a comparison between zero forcing based achievable rates"
    - "mimo broadcast channels with block diagonalization and finite rate feedback"
    - "mimo broadcast channels with finite rate feedback"

Connected through hyperedge HE-5 (induced by source paper "how much feedback is required in mimo broadcast channels"):
  with members:
    - "mimo broadcast channels with finite rate feedback"
    - "on the user selection for mimo broadcast channels"

Connected through hyperedge HE-6 (induced by source paper "unequal dimensional small balls and quantization on grassmann manifolds"):
  with members:
    - "quantization bounds on grassmann manifolds of arbitrary dimensions and mimo communications with feedback"
    - "on the information rate of mimo systems with finite rate channel state feedback using beamforming and power on off strategy"

Connected through hyperedge HE-7 (induced by source paper "mimo broadcast channels with finite rate feedback"):
  with members:
    - "high snr analysis of mimo broadcast channels"

Connected through hyperedge HE-8 (induced by source paper "quantization bounds on grassmann manifolds and applications to mimo communications"):
  with members:
    - "quantization bounds on grassmann manifolds of arbitrary dimensions and mimo communications with feedback"

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)