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: "product superposition for mimo broadcast channels"
  Abstract: This paper considers the multiantenna broadcast channel without transmit-side channel state information (CSIT). For this channel, it has been known that when all receivers have channel state information (CSIR), the degrees of freedom (DoF) cannot be improved beyond what is available via TDMA. The same is true if none of the receivers possess CSIR. This paper shows that an entirely new scenario emerges when receivers have unequal CSIR. In particular, orthogonal transmission is no longer DoF-optimal when one receiver has CSIR and the other does not. A multiplicative superposition is proposed for this scenario and shown to attain the optimal degrees of freedom under a wide set of antenna configurations and coherence lengths. Two signaling schemes are constructed based on the multiplicative superposition. In the first method, the messages of the two receivers are carried in the row and column spaces of a matrix, respectively. This method works better than orthogonal transmission while reception at each receiver is still interference free. The second method uses coherent signaling for the receiver with CSIR, and Grassmannian signaling for the receiver without CSIR. This second method requires interference cancellation at the receiver with CSIR, but achieves higher DoF than the first method.

Connected through hyperedge HE-1 (induced by source paper "degrees of freedom of the broadcast channel with hybrid csi at transmitter and receivers"):
  with members:
    - "coherence disparity in broadcast and multiple access channels"
    - "coherent product superposition for downlink multiuser mimo"
    - "secure degrees of freedom region of the two user miso broadcast channel with alternating csit"
    - "aligned image sets under channel uncertainty settling a conjecture by lapidoth shamai and wigger on the collapse of degrees of freedom under finite precision csit"
    - "on the degrees of freedom of the 3 user miso broadcast channel with hybrid csit"
    - "the degrees of freedom region of temporally correlated mimo networks with delayed csit"
    - "degrees of freedom of time correlated miso broadcast channel with delayed csit"
    - "optimal use of current and outdated channel state information degrees of freedom of the miso bc with mixed csit"

Connected through hyperedge HE-2 (induced by source paper "coherence disparity in broadcast and multiple access channels"):
  with members:
    - "coherent product superposition for downlink multiuser mimo"
    - "aligned image sets under channel uncertainty settling a conjecture by lapidoth shamai and wigger on the collapse of degrees of freedom under finite precision csit"
    - "on the degrees of freedom of the 3 user miso broadcast channel with hybrid csit"
    - "the degrees of freedom region of temporally correlated mimo networks with delayed csit"
    - "on the degrees of freedom of the k user time correlated broadcast channel with delayed csit"
    - "on the dof region of the k user miso broadcast channel with hybrid csit"
    - "degrees of freedom region of the miso broadcast channel with general mixed csit"
    - "optimal use of current and outdated channel state information degrees of freedom of the miso bc with mixed csit"

Connected through hyperedge HE-3 (induced by source paper "coherent product superposition for downlink multiuser mimo"):
  with members:
    - "mimo broadcast channels with finite rate 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)