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: "opportunistic relay selection with limited feedback"
  Abstract: It has been shown that a decentralized relay selection protocol based on opportunistic feedback from the relays yields good throughput performance in dense wireless networks. This selection strategy supports a hybrid-ARQ transmission approach where relays forward parity information to the destination in the event of a decoding error. Such an approach, however, suffers a loss compared to centralized strategies that select relays with the best channel gain to the destination. This paper closes the performance gap by adding another level of channel feedback to the decentralized relay selection problem. It is demonstrated that only one additional bit of feedback is necessary for good throughput performance. The performance impact of varying key parameters such as the number of relays and the channel feedback threshold is discussed. An accompanying bit error rate analysis demonstrates the importance of relay selection

Connected through hyperedge HE-1 (induced by source paper "the impact of channel feedback on opportunistic relay selection for hybrid arq in wireless networks"):
  with members:
    - "hybrid arq in multihop networks with opportunistic relay selection"
    - "parity forwarding for multiple relay networks"
    - "a simple cooperative diversity method based on network path selection"

Connected through hyperedge HE-2 (induced by source paper "an efficient adaptive distributed space time coding scheme for cooperative relaying"):
  with members:
    - "a simple cooperative diversity method based on network path selection"

Connected through hyperedge HE-3 (induced by source paper "analysis of uncoordinated opportunistic two hop wireless ad hoc systems"):
  with members:
    - "opportunistic relaying in wireless networks"

Connected through hyperedge HE-4 (induced by source paper "power bandwidth tradeoff in multiuser relay channels with opportunistic scheduling"):
  with members:
    - "multihop diversity in wideband ofdm systems the impact of spatial reuse and frequency selectivity"
    - "power bandwidth tradeoff in dense multi antenna relay networks"
    - "opportunism in multiuser relay channels scheduling routing and spectrum reuse"
    - "cooperative relay broadcast channels"
    - "high snr analysis of mimo broadcast channels"

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)