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: "optimal transmit power allocation for mimo two way cognitive relay networks with multiple relays"
  Abstract: In this letter, we consider a multiple-input multiple-output two-way cognitive radio system under a spectrum sharing scenario, where primary and secondary users operate on the same frequency band. The secondary terminals aims to exchange different messages with each other using multiple relays where each relay employs an amplify-and-forward strategy. The main objective of our work is to maximize the secondary sum rate allowed to share the spectrum with the primary users by respecting a primary user tolerated interference threshold. In this context, we derive a closed-form expression of the optimal power allocated to each antenna of the terminals. We then discuss the impact of some system parameters on the performance in the numerical result section.

Connected through hyperedge HE-1 (induced by source paper "cyclic communication and the inseparability of mimo multi way relay channels"):
  with members:
    - "spectral and energy efficiency in 3 way relay channels with circular message exchanges"
    - "simultaneous diagonalization on the dof region of the k user mimo multi way relay channel"
    - "beyond one way communication degrees of freedom of multi way relay mimo interference networks"
    - "approximate sum capacity of the y channel"
    - "degrees of freedom for the mimo multi way relay channel"
    - "the deterministic multicast capacity of 4 node relay networks"
    - "the degrees of freedom of the mimo y channel"
    - "divide and conquer approaching the capacity of the two pair bidirectional gaussian relay network"

Connected through hyperedge HE-2 (induced by source paper "simultaneous diagonalization on the dof region of the k user mimo multi way relay channel"):
  with members:
    - "beyond one way communication degrees of freedom of multi way relay mimo interference networks"
    - "approximate sum capacity of the y channel"
    - "degrees of freedom for the mimo multi way relay channel"
    - "the deterministic multicast capacity of 4 node relay networks"
    - "the degrees of freedom of the mimo y channel"
    - "divide and conquer approaching the capacity of the two pair bidirectional gaussian relay network"
    - "on the equal rate capacity of the awgn multiway relay channel"
    - "signal space alignment for the gaussian y channel"

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)