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: "on the capacity and diversity multiplexing tradeoff of the two way relay channel"
  Abstract: This paper considers a multiple input multiple output (MIMO) two-way relay channel, where two nodes want to exchange data with each other using multiple relays. An iterative algorithm is proposed to achieve the optimal achievable rate region, when each relay employs an amplify and forward (AF) strategy. #R##N#The iterative algorithm solves a power minimization problem at every step, subject to minimum signal-to-interference-and-noise ratio constraints, which is non-convex, however, for which the Karush Kuhn Tuker conditions are sufficient for optimality. The optimal AF strategy assumes global channel state information (CSI) at each relay. To simplify the CSI requirements, a simple amplify and forward strategy, called dual channel matching, is also proposed, that requires only local channel state information, and whose achievable rate region is close to that of the optimal AF strategy. In the asymptotic regime of large number of relays, we show that the achievable rate region of the dual channel matching and an upper bound differ by only a constant term and establish the capacity scaling law of the two-way relay channel. Relay strategies achieving optimal diversity-multiplexing tradeoff are also considered with a single relay node. A compress and forward strategy is shown to be optimal for achieving diversity multiplexing tradeoff for the full-duplex case, in general, and for the half-duplex case in some cases.

Connected through hyperedge HE-1 (induced by source paper "degrees of freedom of the mimo three way channel with node intermittency"):
  with members:
    - "on the degrees of freedom of the mimo three way channel with intermittent connectivity"
    - "adaptation is useless for two discrete additive noise two way channels"
    - "degrees of freedom of the bursty mimo x channel without feedback"
    - "three way channels with multiple unicast sessions capacity approximation via network transformation"
    - "resource allocation for energy efficient 3 way relay channels"
    - "gaussian interference channel with intermittent feedback"
    - "a survey on device to device communication in cellular networks"
    - "beyond one way communication degrees of freedom of multi way relay mimo interference networks"

Connected through hyperedge HE-2 (induced by source paper "multipair two way half duplex relaying with massive arrays and imperfect csi"):
  with members:
    - "performance analysis and scaling law of mrc mrt relaying with csi error in massive mimo systems"
    - "multipair full duplex relaying with massive arrays and linear processing"
    - "massive mimo with optimal power and training duration allocation"
    - "massive mimo for next generation wireless systems"
    - "multi pair amplify and forward relaying with very large antenna arrays"
    - "scaling up mimo opportunities and challenges with very large arrays"
    - "relay selection and resource allocation for two way df af cognitive radio networks"
    - "energy and spectral efficiency of very large multiuser mimo systems"

Connected through hyperedge HE-3 (induced by source paper "on the capacity regions of two way diamond channels"):
  with members:
    - "on the symmetric k user interference channels with limited feedback"
    - "on the capacity and degrees of freedom regions of two user mimo interference channels with limited receiver cooperation"
    - "design and characterization of a full duplex multiantenna system for wifi networks"
    - "nested lattice codes for gaussian two way relay channels"
    - "lattice coding for the two way two relay channel"
    - "the gaussian two way diamond channel"
    - "on the capacity region and the generalized degrees of freedom region for the mimo interference channel with feedback"
    - "divide and conquer approaching the capacity of the two pair bidirectional gaussian relay network"

Connected through hyperedge HE-4 (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"
    - "optimal transmit power allocation for mimo two way cognitive relay networks with multiple relays"

Connected through hyperedge HE-5 (induced by source paper "energy efficiency optimization in relay assisted mimo systems with perfect and statistical csi"):
  with members:
    - "cooperative algorithms for mimo amplify and forward relay networks"
    - "energy efficiency optimization for mimo broadcast channels"
    - "joint source and relay precoding designs for mimo two way relaying based on mse criterion"
    - "power allocation in two hop amplify and forward mimo relay systems with qos requirements"
    - "framework for link level energy efficiency optimization with informed transmitter"
    - "energy efficient precoding for multiple antenna terminals"
    - "energy efficient resource allocation in multiuser mimo systems a game theoretic framework"
    - "energy efficient communications in cdma networks a game theoretic analysis considering operating costs"

Connected through hyperedge HE-6 (induced by source paper "capacity region bounds and resource allocation for two way ofdm relay channels"):
  with members:
    - "outer bounds for the capacity region of a gaussian two way relay channel"
    - "optimal power allocation for two way decode and forward ofdm relay networks"
    - "a tutorial on the optimization of amplify and forward mimo relay systems"
    - "optimal real time spectrum sharing between cooperative relay and ad hoc networks"
    - "optimization framework and graph based approach for relay assisted bidirectional ofdma cellular networks"
    - "broadcast capacity region of two phase bidirectional relaying"
    - "mimo two way relay channel diversity multiplexing tradeoff analysis"

Connected through hyperedge HE-7 (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"
    - "grassmannian beamforming for mimo amplify and forward relaying"
    - "optimal beamforming for two way multi antenna relay channel with analogue network coding"
    - "physical layer network coding"

Connected through hyperedge HE-8 (induced by source paper "reliable physical layer network coding"):
  with members:
    - "an algebraic approach to physical layer network coding"
    - "divide and conquer approaching the capacity of the two pair bidirectional gaussian relay network"
    - "wireless network information flow a deterministic approach"
    - "nested lattice codes for gaussian relay networks with interference"
    - "on achieving local view capacity via maximal independent graph scheduling"
    - "list decoding for nested lattices and applications to relay channels"
    - "the approximate capacity of the many to one and one to many gaussian interference channels"
    - "capacity theorems for the awgn multi way relay 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)