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: "grassmannian beamforming for mimo amplify and forward relaying"
  Abstract: We consider the problem of beamforming codebook design for limited feedback half-duplex multiple-input multiple output (MIMO) amplify-and-forward (AF) relay system. In the first part of the paper, the direct link between the source and the destination is ignored. Assuming perfect channel state information (CSI), we show that the source and the relay should map their signals to the dominant right singular vectors of the source-relay and relay-destination channels. For the limited feedback scenario, we prove the appropriateness of Grassmannian codebooks as the source and relay beamforming codebooks based on the distributions of the optimal source and relay beamforming vectors. In the second part of the paper, the direct link is considered in the problem model. Assuming perfect CSI, we derive the optimization problem that identifies the optimal source beamforming vector and show that the solution to this problem is uniformly distributed on the unit sphere for independent and identically distributed (i.i.d) Rayleigh channels. For the limited feedback scenario, we justify the appropriateness of Grassmannian codebooks for quantizing the optimal source beamforming vector based on its distribution. Finally, a modified quantization scheme is presented, which introduces a negligible penalty in the system performance but significantly reduces the required number of feedback bits.

Connected through hyperedge HE-1 (induced by source paper "wireless powered dual hop multi antenna relaying systems impact of csi and antenna correlation"):
  with members:
    - "on the performance of multi antenna wireless powered communications with energy beamforming"
    - "an overview of sustainable green 5g networks"
    - "training based swipt optimal power splitting at the receiver"
    - "joint wireless information and power transfer for an autonomous multiple antenna relay system"
    - "wireless powered communications performance analysis and optimization"
    - "energy efficient resource allocation for wireless powered communication networks"
    - "wireless information and power transfer in relay systems with multiple antennas and interference"
    - "harvest then cooperate wireless powered cooperative communications"

Connected through hyperedge HE-2 (induced by source paper "joint wireless information and power transfer for an autonomous multiple antenna relay system"):
  with members:
    - "joint resource optimization for multicell networks with wireless energy harvesting relays"
    - "user cooperation in wireless powered communication networks"
    - "power allocation strategies in energy harvesting wireless cooperative networks"
    - "relaying protocols for wireless energy harvesting and information processing"
    - "mimo broadcasting for simultaneous wireless information and power transfer"

Connected through hyperedge HE-3 (induced by source paper "joint source and relay precoding designs for mimo two way relaying based on mse criterion"):
  with members:
    - "on design of collaborative beamforming for two way relay networks"
    - "optimal beamforming for two way multi antenna relay channel with analogue network coding"
    - "on the capacity and diversity multiplexing tradeoff of the two way relay channel"
    - "physical layer network coding"

Connected through hyperedge HE-4 (induced by source paper "precoder design for multi antenna partial decode and forward pdf cooperative systems with statistical csit and mmse sic receivers"):
  with members:
    - "distributed power allocation strategies for parallel relay networks"

Connected through hyperedge HE-5 (induced by source paper "stochastic control of event driven feedback in multiantenna interference channels"):
  with members:
    - "multi antenna communication in ad hoc networks achieving mimo gains with simo transmission"
    - "adaptive bit partitioning for multicell intercell interference nulling with delayed limited feedback"
    - "event driven optimal feedback control for multiantenna beamforming"
    - "cooperative feedback for multi antenna cognitive radio networks"
    - "interference alignment with limited feedback"
    - "space division multiple access with a sum feedback rate constraint"
    - "interference alignment and the degrees of freedom for the k user interference channel"
    - "mimo broadcast channels with finite rate feedback"

Connected through hyperedge HE-6 (induced by source paper "on design of collaborative beamforming for two way relay networks"):
  with members:
    - "network beamforming using relays with perfect channel information"
    - "optimal beamforming for two way multi antenna relay channel with analogue network coding"
    - "performance bounds for bi directional coded cooperation protocols"

Connected through hyperedge HE-7 (induced by source paper "distributed beamforming in wireless multiuser relay interference networks with quantized feedback"):
  with members:
    - "distributed scalar quantization for computing high resolution analysis and extensions"
    - "relay selection and performance analysis in multiple user networks"
    - "interference alignment with limited feedback"
    - "combining beamforming and space time coding using noisy quantized feedback"
    - "network beamforming using relays with perfect channel information"
    - "power bandwidth tradeoff in dense multi antenna relay networks"
    - "a simple cooperative diversity method based on network path selection"
    - "mimo broadcast channels with finite rate feedback"

Connected through hyperedge HE-8 (induced by source paper "on design of distributed beamforming for two way relay networks"):
  with members:
    - "broadcast capacity region of two phase bidirectional relaying"
    - "network beamforming using relays with perfect channel information"
    - "optimal beamforming for two way multi antenna relay channel with analogue network coding"

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)