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 multiuser zero forcing with per antenna power constraints for network mimo coordination"
  Abstract: We consider a multicell multiple-input multiple-output (MIMO) coordinated downlink transmission, also known as network MIMO, under per-antenna power constraints. We investigate a simple multiuser zero-forcing (ZF) linear precoding technique known as block diagonalization (BD) for network MIMO. The optimal form of BD with per-antenna power constraints is proposed. It involves a novel approach of optimizing the precoding matrices over the entire null space of other users' transmissions. An iterative gradient descent method is derived by solving the dual of the throughput maximization problem, which finds the optimal precoding matrices globally and efficiently. The comprehensive simulations illustrate several network MIMO coordination advantages when the optimal BD scheme is used. Its achievable throughput is compared with the capacity region obtained through the recently established duality concept under per-antenna power constraints.

Connected through hyperedge HE-1 (induced by source paper "networked mimo with fractional joint transmission in energy harvesting systems"):
  with members:
    - "comp meets smart grid a new communication and energy cooperation paradigm"
    - "energy cooperation in energy harvesting communications"
    - "energy cooperation in cellular networks with renewable powered base stations"
    - "optimal power allocation for energy harvesting and power grid coexisting wireless communication systems"
    - "broadcasting with an energy harvesting rechargeable transmitter"
    - "sum rate optimal power policies for energy harvesting transmitters in an interference channel"
    - "transmission with energy harvesting nodes in fading wireless channels optimal policies"
    - "networked mimo with clustered linear precoding"

Connected through hyperedge HE-2 (induced by source paper "linear precoding and equalization for network mimo with partial cooperation"):
  with members:
    - "multi cell mimo downlink with cell cooperation and fair scheduling a large system limit analysis"
    - "rank constrained schur convex optimization with multiple trace log det constraints"
    - "mimo b mac interference network optimization under rate constraints by polite water filling and duality"
    - "adaptive beamforming in interference networks via bi directional training"
    - "duality polite water filling and optimization for mimo b mac interference networks and itree networks"
    - "multiuser miso transmitter optimization for intercell interference mitigation"
    - "linear precoding in cooperative mimo cellular networks with limited coordination clusters"
    - "cooperative algorithms for mimo interference channels"

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)