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: "energy efficient resource allocation in multiuser mimo systems a game theoretic framework"
  Abstract: This paper focuses on the cross-layer issue of resource allocation for energy efficiency in the uplink of a multiuser MIMO wireless communication system. Assuming that all of the transmitters and the uplink receiver are equipped with multiple antennas, the situation considered is that in which each terminal is allowed to vary its transmit power, beamforming vector, and uplink receiver in order to maximize its own utility, which is defined as the ratio of data throughput to transmit power; the case in which non-linear interference cancellation is used at the receiver is also investigated. Applying a game-theoretic formulation, several non-cooperative games for utility maximization are thus formulated, and their performance is compared in terms of achieved average utility, achieved average SINR and average transmit power at the Nash equilibrium. Numerical results show that the use of the proposed cross-layer resource allocation policies brings remarkable advantages to the network performance.

Connected through hyperedge HE-1 (induced by source paper "totally distributed energy efficient transmission in mimo interference channels"):
  with members:
    - "energy efficiency optimization in relay assisted mimo systems with perfect and statistical csi"
    - "what will 5g be"
    - "distributed optimal beamformers for cognitive radios robust to channel uncertainties"
    - "the mimo iterative waterfilling algorithm"
    - "competitive design of multiuser mimo systems based on game theory a unified view"
    - "cognitive beamforming made practical effective interference channel and learning throughput tradeoff"
    - "energy efficient communications in cdma networks a game theoretic analysis considering operating costs"
    - "energy efficient resource allocation in wireless networks"

Connected through hyperedge HE-2 (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"
    - "on the capacity and diversity multiplexing tradeoff of the two way relay channel"
    - "energy efficient communications in cdma networks a game theoretic analysis considering operating costs"

Connected through hyperedge HE-3 (induced by source paper "an energy efficient framework for the analysis of mimo slow fading channels"):
  with members:
    - "energy efficient precoding for multiple antenna terminals"
    - "asynchronous capacity per unit cost"
    - "methodologies for analyzing equilibria in wireless games"
    - "multiuser mimo achievable rates with downlink training and channel state feedback"

Connected through hyperedge HE-4 (induced by source paper "energy efficient precoding for multiple antenna terminals"):
  with members:
    - "introducing hierarchy in energy games"

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)