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: "distributed massive mimo in cellular networks impact of imperfect hardware and number of oscillators"
  Abstract: Distributed massive multiple-input multiple-output (MIMO) combines the array gain of coherent MIMO processing with the proximity gains of distributed antenna setups. In this paper, we analyze how transceiver hardware impairments affect the downlink with maximum ratio transmission. We derive closed-form spectral efficiencies expressions and study their asymptotic behavior as the number of the antennas increases. We prove a scaling law on the hardware quality, which reveals that massive MIMO is resilient to additive distortions, while multiplicative phase noise is a limiting factor. It is also better to have separate oscillators at each antenna than one per BS.

Connected through hyperedge HE-1 (induced by source paper "power control for massive mimo systems with nonorthogonal pilots"):
  with members:
    - "large scale fading decoding in cellular massive mimo systems with spatially correlated channels"
    - "pilot contamination mitigation with reduced rf chains"
    - "massive mimo has unlimited capacity"
    - "joint pilot design and uplink power allocation in multi cell massive mimo systems"
    - "optimal pilot and payload power control in single cell massive mimo systems"
    - "a parallel decomposition method for nonconvex stochastic multi agent optimization problems"

Connected through hyperedge HE-2 (induced by source paper "uplink performance of multi antenna cellular networks with co operative base stations and user centric clustering"):
  with members:
    - "ergodic spectral efficiency in mimo cellular networks"
    - "on a user centric base station cooperation scheme for reliable communications"
    - "full duplex cloud ran with uplink downlink remote radio head association"
    - "heterogeneous cellular networks with spatio temporal traffic delay analysis and scheduling"
    - "cooperative base station coloring for pair wise multi cell coordination"
    - "the world s first real time testbed for massive mimo design implementation and validation"
    - "uplink and downlink rate analysis of a full duplex c ran with radio remote head association"
    - "massive mimo with non ideal arbitrary arrays hardware scaling laws and circuit aware design"

Connected through hyperedge HE-3 (induced by source paper "ml detection in phase noise impaired simo channels with uplink training"):
  with members:
    - "optimal detection in training assisted simo systems with phase noise impairments"
    - "capacity of simo and miso phase noise channels with common separate oscillators"
    - "uplink performance of time reversal mrc in massive mimo systems subject to phase noise"
    - "massive mimo with non ideal arbitrary arrays hardware scaling laws and circuit aware design"
    - "massive mimo systems with non ideal hardware energy efficiency estimation and capacity limits"
    - "calculation of the performance of communication systems from measured oscillator phase noise"
    - "massive mimo for next generation wireless systems"
    - "capacity bounds for mimo microwave backhaul links affected by phase noise"

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)