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: "differential modulation for bi directional relaying with analog network coding"
  Abstract: In this paper, we propose an analog network coding scheme with differential modulation (ANC-DM) using amplify-and-forward protocol for bidirectional relay networks when neither the source nodes nor the relay knows the channel state information (CSI). The performance of the proposed ANC-DM scheme is analyzed and a simple asymptotic bit error rate (BER) expression is derived. The analytical results are verified through simulations. It is shown that the BER performance of the proposed differential scheme is about 3 dB away from that of the coherent detection scheme. To improve the system performance, the optimum power allocation between the sources and the relay is determined based on the simplified BER. Simulation results indicate that the proposed differential scheme with optimum power allocation yields 1-2 dB performance improvement over an equal power allocation scheme.

Connected through hyperedge HE-1 (induced by source paper "performance analysis of adaptive physical layer network coding for wireless two way relaying"):
  with members:
    - "wireless bidirectional relaying and latin squares"
    - "channel quantization for physical layer network coded two way relaying"
    - "multilevel coding schemes for compute and forward"
    - "power allocation strategies and lattice based coding schemes for bi directional relaying"
    - "physical network coding in two way wireless relay channels"

Connected through hyperedge HE-2 (induced by source paper "joint relay and jammer selection for secure two way relay networks"):
  with members:
    - "cooperative secret communication with artificial noise in symmetric interference channel"
    - "the role of feedback in two way secure communications"
    - "secrecy in cooperative relay broadcast channels"
    - "achievable rates for two way wire tap channels"
    - "achievable rates for the general gaussian multiple access wire tap channel with collective secrecy"
    - "the relay eavesdropper channel cooperation for secrecy"

Connected through hyperedge HE-3 (induced by source paper "on two way communications for cooperative multiple source pairs through a multi antenna relay"):
  with members:
    - "optimal beamforming for two way multi antenna relay channel with analogue network coding"
    - "capacity of gaussian mimo bidirectional broadcast channels"
    - "physical layer 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)