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: "compute and forward in cell free massive mimo great performance with low backhaul load"
  Abstract: In this paper, we consider the uplink of cell-free massive MIMO systems, where a large number of distributed single antenna access points (APs) serve a much smaller number of users simultaneously via limited backhaul. For the first time, we investigate the performance of compute-and-forward (C&F) in such an ultra dense network with a realistic channel model (including fading, pathloss and shadowing). By utilising the characteristic of pathloss, a low complexity coefficient selection algorithm for C\&F is proposed. We also give a greedy AP selection method for message recovery. Additionally, we compare the performance of C&F to some other promising linear strategies for distributed massive MIMO, such as small cells (SC) and maximum ratio combining (MRC). Numerical results reveal that C&F not only reduces the backhaul load, but also significantly increases the system throughput for the symmetric scenario.

Connected through hyperedge HE-1 (induced by source paper "transmission strategies for cell free massive mimo with limited capacity fronthaul links"):
  with members:
    - "cell free massive mimo with limited backhaul"
    - "spectral and energy efficiency of cell free massive mimo systems with hardware impairments"
    - "spectral efficiency of multipair massive mimo two way relaying with hardware impairments"
    - "on the total energy efficiency of cell free massive mimo"
    - "channel hardening and favorable propagation in cell free massive mimo with stochastic geometry"
    - "energy efficiency in cell free massive mimo with zero forcing precoding design"
    - "analysis and design of secure massive mimo systems in the presence of hardware impairments"
    - "cell free massive mimo versus small cells"

Connected through hyperedge HE-2 (induced by source paper "user centric 5g cellular networks resource allocation and comparison with the cell free massive mimo approach"):
  with members:
    - "cell free massive mimo with limited backhaul"
    - "cell free and user centric massive mimo at millimeter wave frequencies"
    - "downlink power control in user centric and cell free massive mimo wireless networks"
    - "cell free massive mimo versus small cells"
    - "how much do downlink pilots improve cell free massive mimo"
    - "cell free massive mimo uniformly great service for everyone"
    - "what will 5g be"

Connected through hyperedge HE-3 (induced by source paper "low complexity coefficient selection algorithms for compute and forward"):
  with members:
    - "polynomially solvable instances of the shortest and closest vector problems with applications to compute and forward"
    - "efficient integer coefficient search for compute and forward"
    - "cell free massive mimo versus small cells"
    - "a linearithmic time algorithm for a shortest vector problem in compute and forward design"
    - "cell free massive mimo uniformly great service for everyone"
    - "adaptive compute and forward with lattice codes over algebraic integers"
    - "a multilevel framework for lattice network coding"
    - "compute and forward finding the best equation"

Connected through hyperedge HE-4 (induced by source paper "on the total energy efficiency of cell free massive mimo"):
  with members:
    - "energy efficient downlink transmission for multicell massive das with pilot contamination"
    - "cell free massive mimo versus small cells"
    - "energy efficiency of downlink transmission strategies for cloud radio access networks"
    - "networked mimo with fractional joint transmission in energy harvesting systems"
    - "how much do downlink pilots improve cell free massive mimo"
    - "deploying dense networks for maximal energy efficiency small cells meet massive mimo"
    - "energy efficiency optimization for mimo distributed antenna systems"
    - "optimal design of energy efficient multi user mimo systems is massive mimo the answer"

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)