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: "multi cell mimo downlink with cell cooperation and fair scheduling a large system limit analysis"
  Abstract: We consider the downlink of a cellular network with multiple cells and multi-antenna base stations. Our model includes distance-dependent pathloss, arbitrary clusters of cooperating cells, and general “fairness” requirements. Beyond Monte Carlo simulation, no efficient computation method to evaluate the ergodic throughput of such systems has been presented, yet. Furthermore, for systems of practical size with tens of cells and hundreds of users per cell, even simulation becomes challenging. We develop an analytic framework based on the combination of results from large random matrix theory and convex optimization. This allows computationally efficient calculation of the system performance in the so-called “large system limit”, i.e., in the limit of a large number of antennas per base station and a large number of users per cell, while the ratio of antennas per user is kept constant. In particular, the system ergodic throughput, subject to per-base station power constraints and to general fairness criteria, is obtained via the iterative solution of a system of fixed-point equations. Comparisons with finite-dimensional simulation results show that the large-system analysis provides remarkably accurate approximations for the actual finite-dimensional systems, even for a small number of users and base station antennas.

Connected through hyperedge HE-1 (induced by source paper "joint user selection power allocation and precoding design with imperfect csit for multi cell mu mimo downlink systems"):
  with members:
    - "optimal pilot and payload power control in single cell massive mimo systems"
    - "on the capacity of cloud radio access networks with oblivious relaying"
    - "on the ergodic rate lower bounds with applications to massive mimo"
    - "massive mimo with imperfect channel covariance information"
    - "sum rate maximization for linearly precoded downlink multiuser miso systems with partial csit a rate splitting approach"
    - "robust transmission in downlink multiuser miso systems a rate splitting approach"
    - "cell free massive mimo versus small cells"
    - "a rate splitting strategy for massive mimo with imperfect csit"

Connected through hyperedge HE-2 (induced by source paper "on the throughput of large but finite mimo networks using schedulers"):
  with members:
    - "tomlinson harashima precoding for multiuser mimo systems with quantized csi feedback and user scheduling"
    - "network mimo with linear zero forcing beamforming large system analysis impact of channel estimation and reduced complexity scheduling"
    - "multi user mimo scheduling in the fourth generation cellular uplink"
    - "user scheduling for heterogeneous multiuser mimo systems a subspace viewpoint"
    - "sum rates rate allocation and user scheduling for multi user mimo vector perturbation precoding"
    - "maximum sum rate of mimo multiuser scheduling with linear receivers"

Connected through hyperedge HE-3 (induced by source paper "pilot contamination mitigation with reduced rf chains"):
  with members:
    - "hybrid analog digital beamforming for massive mimo systems"
    - "partially connected hybrid precoding in mm wave systems with dynamic phase shifter networks"
    - "alternating minimization algorithms for hybrid precoding in millimeter wave mimo systems"
    - "hybrid mimo architectures for millimeter wave communications phase shifters or switches"
    - "smart pilot assignment for massive mimo"
    - "channel estimation and hybrid precoding for millimeter wave cellular systems"
    - "pilot beam pattern design for channel estimation in massive mimo systems"
    - "what will 5g be"

Connected through hyperedge HE-4 (induced by source paper "interference aware flexible tdd design for massive mimo 5g systems"):
  with members:
    - "what will 5g be"
    - "scaling up mimo opportunities and challenges with very large arrays"
    - "pilot contamination and precoding in multi cell tdd systems"

Connected through hyperedge HE-5 (induced by source paper "secure massive mimo transmission with an active eavesdropper"):
  with members:
    - "channel acquisition for massive mimo ofdm with adjustable phase shift pilots"
    - "linear precoding of data and artificial noise in secure massive mimo systems"
    - "physical layer security in heterogeneous cellular networks"
    - "an overview of transmission theory and techniques of large scale antenna systems for 5g wireless communications"
    - "joint csit acquisition based on low rank matrix completion for fdd massive mimo systems"
    - "physical layer security in massive mimo"
    - "large scale mimo relaying techniques for physical layer security af or df"
    - "multi antenna relay aided wireless physical layer security"

Connected through hyperedge HE-6 (induced by source paper "a new energy efficient beamforming strategy for miso interfering broadcast channels based on large systems analysis"):
  with members:
    - "optimal design of energy efficient multi user mimo systems is massive mimo the answer"
    - "massive mimo and small cells improving energy efficiency by optimal soft cell coordination"
    - "large system analysis of linear precoding in correlated miso broadcast channels under limited feedback"
    - "energy and spectral efficiency of very large multiuser mimo systems"
    - "framework for link level energy efficiency optimization with informed transmitter"

Connected through hyperedge HE-7 (induced by source paper "simple energy efficiency maximization methods for mu miso systems based on saturation power"):
  with members:
    - "optimal design of energy efficient multi user mimo systems is massive mimo the answer"
    - "massive mimo and small cells improving energy efficiency by optimal soft cell coordination"
    - "large system analysis of linear precoding in correlated miso broadcast channels under limited feedback"
    - "energy and spectral efficiency of very large multiuser mimo systems"
    - "framework for link level energy efficiency optimization with informed transmitter"

Connected through hyperedge HE-8 (induced by source paper "soft pilot reuse and multi cell block diagonalization precoding for massive mimo systems"):
  with members:
    - "blind pilot decontamination"
    - "noncoherent trellis coded quantization a practical limited feedback technique for massive mimo systems"
    - "scaling up mimo opportunities and challenges with very large arrays"
    - "energy and spectral efficiency of very large multiuser mimo systems"

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)