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: "coordinated beamforming with relaxed zero forcing the sequential orthogonal projection combining method and rate control"
  Abstract: In this paper, coordinated beamforming based on relaxed zero forcing (RZF) for transmitter-receiver pair multiple-input single-output (MISO) and multiple-input multiple-output (MIMO) interference channels is considered. In the RZF coordinated beamforming, conventional zero-forcing interference leakage constraints are relaxed so that some predetermined interference leakage to undesired receivers is allowed in order to increase the beam design space for larger rates than those of the zero-forcing (ZF) scheme or to make beam design feasible when ZF is impossible. In the MISO case, it is shown that the rate-maximizing beam vector under the RZF framework for a given set of interference leakage levels can be obtained by sequential orthogonal projection combining (SOPC). Based on this, exact and approximate closed-form solutions are provided in two-user and three-user cases, respectively, and an efficient beam design algorithm for RZF coordinated beamforming is provided in general cases. Furthermore, the rate control problem under the RZF framework is considered. A centralized approach and a distributed heuristic approach are proposed to control the position of the designed rate-tuple in the achievable rate region. Finally, the RZF framework is extended to MIMO interference channels by deriving a new lower bound on the rate of each user.

Connected through hyperedge HE-1 (induced by source paper "two stage beamformer design for massive mimo downlink by trace quotient formulation"):
  with members:
    - "pilot signal design for massive mimo systems a received signal to noise ratio based approach"
    - "pilot beam pattern design for channel estimation in massive mimo systems"
    - "a new approach to user scheduling in massive multi user mimo broadcast channels"
    - "training sequence design for feedback assisted hybrid beamforming in massive mimo systems"
    - "two tier precoding for fdd multi cell massive mimo time varying interference networks"
    - "downlink training techniques for fdd massive mimo systems open loop and closed loop training with memory"
    - "scaling up mimo opportunities and challenges with very large arrays"

Connected through hyperedge HE-2 (induced by source paper "cb refim a practical coordinated beamforming in multicell networks"):
  with members:
    - "refim a practical interference management in heterogeneous wireless access networks"
    - "optimality properties distributed strategies and measurement based evaluation of coordinated multicell ofdma transmission"
    - "optimal beamforming in interference networks with perfect local channel information"
    - "optimal distributed beamforming for miso interference channels"

Connected through hyperedge HE-3 (induced by source paper "on the pareto optimal beam structure and design for multi user mimo interference channels"):
  with members:
    - "alternating rate profile optimization in single stream mimo interference channels"
    - "scaling up mimo opportunities and challenges with very large arrays"
    - "pareto boundary of the rate region for single stream mimo interference channels linear transceiver design"
    - "pareto characterization of the multicell mimo performance region with simple receivers"
    - "optimal beamforming in interference networks with perfect local channel information"
    - "cooperative interference management with miso beamforming"

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)