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: "distributed optimal beamformers for cognitive radios robust to channel uncertainties"
  Abstract: Through spatial multiplexing and diversity, multi-input multi-output (MIMO) cognitive radio (CR) networks can markedly increase transmission rates and reliability, while controlling the interference inflicted to peer nodes and primary users (PUs) via beamforming. The present paper optimizes the design of transmit- and receive-beamformers for ad hoc CR networks when CR-to-CR channels are known, but CR-to-PU channels cannot be estimated accurately. Capitalizing on a norm-bounded channel uncertainty model, the optimal beamforming design is formulated to minimize the overall mean-square error (MSE) from all data streams, while enforcing protection of the PU system when the CR-to-PU channels are uncertain. Even though the resultant optimization problem is non-convex, algorithms with provable convergence to stationary points are developed by resorting to block coordinate ascent iterations, along with suitable convex approximation techniques. Enticingly, the novel schemes also lend themselves naturally to distributed implementations. Numerical tests are reported to corroborate the analytical findings.

Connected through hyperedge HE-1 (induced by source paper "context aware decentralized invariant signaling for opportunistic communications"):
  with members:
    - "state of the art taxonomy and open issues on cognitive radio networks with noma"
    - "resource allocation and fairness in wireless powered cooperative cognitive radio networks"
    - "covariance based ofdm spectrum sensing with sub nyquist samples"
    - "vandermonde subspace frequency division multiplexing for two tiered cognitive radio networks"
    - "enhanced intercell interference coordination challenges in heterogeneous networks"
    - "exploiting multi antennas for opportunistic spectrum sharing in cognitive radio networks"

Connected through hyperedge HE-2 (induced by source paper "parallel and distributed methods for nonconvex optimization part ii applications"):
  with members:
    - "parallel selective algorithms for big data optimization"
    - "parallel and distributed methods for nonconvex optimization part i theory"
    - "decomposition by partial linearization parallel optimization of multi agent systems"
    - "weighted fair multicast multigroup beamforming under per antenna power constraints"
    - "alternating rate profile optimization in single stream mimo interference channels"
    - "coordinated multicast beamforming in multicell networks"
    - "sum rate maximization in two way af mimo relaying polynomial time solutions to a class of dc programming problems"
    - "achieving global optimality for weighted sum rate maximization in the k user gaussian interference channel with multiple antennas"

Connected through hyperedge HE-3 (induced by source paper "learning to be green robust energy efficiency maximization in dynamic mimo ofdm systems"):
  with members:
    - "learning in an uncertain world mimo covariance matrix optimization with imperfect feedback"
    - "adaptive power allocation and control in time varying multi carrier mimo networks"
    - "energy efficient precoder design for mimo ofdm with rate dependent circuit power"
    - "energy aware competitive power allocation for heterogeneous networks under qos constraints"
    - "joint channel selection and power control in infrastructureless wireless networks a multiplayer multiarmed bandit framework"
    - "massive mimo for next generation wireless systems"
    - "what will 5g be"
    - "transmit without regrets online optimization in mimo ofdm cognitive radio systems"

Connected through hyperedge HE-4 (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"
    - "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 resource allocation in multiuser mimo systems a game theoretic framework"
    - "energy efficient communications in cdma networks a game theoretic analysis considering operating costs"
    - "energy efficient resource allocation in wireless networks"

Connected through hyperedge HE-5 (induced by source paper "joint sensing and reception design of simo hybrid cognitive radio systems"):
  with members:
    - "coordinated shared spectrum precoding with distributed csit"

Connected through hyperedge HE-6 (induced by source paper "parallel and distributed methods for nonconvex optimization part i theory"):
  with members:
    - "signal processing and optimal resource allocation for the interference channel"
    - "decomposition by partial linearization parallel optimization of multi agent systems"
    - "decomposition by successive convex approximation a unifying approach for linear transceiver design in heterogeneous networks"
    - "linear transceiver design for a mimo interfering broadcast channel achieving max min fairness"
    - "optimal distributed beamforming for miso interference channels"

Connected through hyperedge HE-7 (induced by source paper "a new distributed dc programming method and its applications"):
  with members:
    - "signal processing and optimal resource allocation for the interference channel"
    - "decomposition by partial linearization parallel optimization of multi agent systems"
    - "joint sensing and power allocation in nonconvex cognitive radio games quasi nash equilibria"
    - "joint sensing and power allocation in nonconvex cognitive radio games nash equilibria and distributed algorithms"
    - "on cooperative relaying schemes for wireless physical layer security"
    - "dynamic resource allocation in cognitive radio networks"
    - "cooperative jamming for wireless physical layer security"

Connected through hyperedge HE-8 (induced by source paper "two design issues in cognitive sub small cell for sojourners"):
  with members:
    - "random subcarrier allocation in ofdm based cognitive radio networks"
    - "green cellular networks a survey some research issues and challenges"

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)