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: "cooperative access networks optimum fronthaul quantization in distributed massive mimo and cloud ran"
  Abstract: We consider cooperative radio access network architectures, especially distributed massive MIMO and Cloud RAN, considering their similarities and differences. We address in particular the major challenge posed to both by the implementation of a high capacity fronthaul network to link the distributed access points to the central processing unit, and consider the effect on uplink performance of quantization of received signals in order to limit fronthaul load. We use the Bussgang decomposition along with a new approach to MMSE estimation of both channel and data to provide the basis of our analysis.

Connected through hyperedge HE-1 (induced by source paper "max min rate of cell free massive mimo uplink with optimal uniform quantization"):
  with members:
    - "on the uplink throughput of zero forcing in cell free massive mimo with coarse quantization"
    - "ubiquitous cell free massive mimo communications"
    - "on the energy efficiency of limited backhaul cell free massive mimo"
    - "cell free massive mimo with limited backhaul"
    - "on the performance of backhaul constrained cell free massive mimo with linear receivers"
    - "network deployment for maximal energy efficiency in uplink with multislope path loss"
    - "enhanced max min sinr for uplink cell free massive mimo systems"
    - "performance of cell free massive mimo systems with mmse and lsfd receivers"

Connected through hyperedge HE-2 (induced by source paper "on the energy efficiency of limited backhaul cell free massive mimo"):
  with members:
    - "on the uplink throughput of zero forcing in cell free massive mimo with coarse quantization"
    - "on the performance of backhaul constrained cell free massive mimo with linear receivers"
    - "enhanced max min sinr for uplink cell free massive mimo systems"
    - "on the total energy efficiency of cell free massive mimo"
    - "robust geometry based user scheduling for large mimo systems under realistic channel conditions"
    - "cell free massive mimo versus small cells"
    - "optimal design of energy efficient multi user mimo systems is massive mimo the answer"

Connected through hyperedge HE-3 (induced by source paper "on the uplink throughput of zero forcing in cell free massive mimo with coarse quantization"):
  with members:
    - "cell free massive mimo versus small cells"

Connected through hyperedge HE-4 (induced by source paper "enhanced max min sinr for uplink cell free massive mimo systems"):
  with members:
    - "cell free massive mimo with limited backhaul"
    - "max min sinr in large scale single cell mu mimo asymptotic analysis and low complexity transceivers"
    - "energy efficient power control a look at 5g wireless technologies"
    - "cell free massive mimo versus small cells"
    - "multiobjective signal processing optimization the way to balance conflicting metrics in 5g systems"

Connected through hyperedge HE-5 (induced by source paper "cell free massive mimo with limited backhaul"):
  with members:
    - "enhanced max min sinr for uplink cell free massive mimo systems"
    - "energy efficient power control a look at 5g wireless technologies"
    - "cell free massive mimo versus small cells"
    - "multiobjective signal processing optimization the way to balance conflicting metrics in 5g systems"

Connected through hyperedge HE-6 (induced by source paper "on the performance of backhaul constrained cell free massive mimo with linear receivers"):
  with members:
    - "enhanced max min sinr for uplink cell free massive mimo systems"
    - "cell free massive mimo versus small cells"

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)