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: "energy efficiency and sum rate when massive mimo meets device to device communication"
  Abstract: This paper considers a scenario of short-range communication, known as device-to-device (D2D) communication, where D2D users reuse the downlink resources of a cellular network to transmit directly to their corresponding receivers. In addition, multiple antennas at the base station (BS) are used in order to simultaneously support multiple cellular users using multiuser or massive MIMO. The network model considers a fixed number of cellular users and that D2D users are distributed according to a homogeneous Poisson point process (PPP). Two metrics are studied, namely, average sum rate (ASR) and energy efficiency (EE). We derive tractable expressions and study the tradeoffs between the ASR and EE as functions of the number of BS antennas and density of D2D users for a given coverage area.

Connected through hyperedge HE-1 (induced by source paper "joint power and resource allocation of d2d communication with low resolution adc"):
  with members:
    - "throughput analysis of massive mimo uplink with low resolution adcs"
    - "pilot reuse among d2d users in d2d underlaid massive mimo systems"
    - "uplink achievable rate for massive mimo systems with low resolution adc"
    - "d2d based v2v communications with latency and reliability constraints"
    - "the interplay between massive mimo and underlaid d2d networking"

Connected through hyperedge HE-2 (induced by source paper "energy efficiency in mimo underlay and overlay device to device communications and cognitive radio systems"):
  with members:
    - "energy efficient power control a look at 5g wireless technologies"
    - "energy efficient resource allocation for device to device underlay communication"
    - "dynamic power control for delay aware device to device communications"
    - "resource allocation under channel uncertainties for relay aided device to device communication underlaying lte a cellular networks"
    - "energy efficiency and spectral efficiency tradeoff in device to device d2d communications"
    - "designing multi user mimo for energy efficiency when is massive mimo the answer"
    - "cognitive beamforming for multiple secondary data streams with individual snr constraints"
    - "efficiency resource allocation for device to device underlay communication systems a reverse iterative combinatorial auction based approach"

Connected through hyperedge HE-3 (induced by source paper "energy efficiency and sum rate tradeoffs for massive mimo systems with underlaid device to device communications"):
  with members:
    - "massive mimo ten myths and one critical question"
    - "an analytical framework for device to device communication in cellular networks"
    - "energy efficient resource allocation for device to device underlay communication"
    - "design aspects of short range millimeter wave networks a mac layer perspective"
    - "the interplay between massive mimo and underlaid d2d networking"
    - "optimal multiuser transmit beamforming a difficult problem with a simple solution structure"
    - "spectrum sharing for device to device communication in cellular networks"
    - "multiobjective signal processing optimization the way to balance conflicting metrics in 5g systems"

Connected through hyperedge HE-4 (induced by source paper "impact of underlaid multi antenna d2d on cellular downlink in massive mimo systems"):
  with members:
    - "the interplay between massive mimo and underlaid d2d networking"
    - "what will 5g be"
    - "scaling up mimo opportunities and challenges with very large arrays"
    - "power control for d2d underlaid cellular networks modeling algorithms and analysis"
    - "modeling heterogeneous network interference using poisson point processes"
    - "energy and spectral efficiency of very large multiuser mimo systems"
    - "a tractable approach to coverage and rate in cellular networks"

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)