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 tradeoffs for massive mimo systems with underlaid device to device communications"
  Abstract: In this paper, we investigate the coexistence of two technologies that have been put forward for the fifth generation (5G) of cellular networks, namely, network-assisted device-to-device (D2D) communications and massive MIMO (multiple-input multiple-output). Potential benefits of both technologies are known individually, but the tradeoffs resulting from their coexistence have not been adequately addressed. To this end, we assume that D2D users reuse the downlink resources of cellular networks in an underlay fashion. In addition, multiple antennas at the BS are used in order to obtain precoding gains and simultaneously support multiple cellular users using multiuser or massive MIMO technique. Two metrics are considered, namely the average sum rate (ASR) and energy efficiency (EE). We derive tractable and directly computable expressions and study the tradeoffs between the ASR and EE as functions of the number of BS antennas, the number of cellular users and the density of D2D users within a given coverage area. Our results show that both the ASR and EE behave differently in scenarios with low and high density of D2D users, and that coexistence of underlay D2D communications and massive MIMO is mainly beneficial in low densities of D2D users.

Connected through hyperedge HE-1 (induced by source paper "optimized power control for massive mimo with underlaid d2d communications"):
  with members:
    - "power control for d2d underlay in multi cell massive mimo networks"
    - "spectral and energy efficiency of uplink d2d underlaid massive mimo cellular networks"
    - "joint pilot design and uplink power allocation in multi cell massive mimo systems"
    - "pilot reuse among d2d users in d2d underlaid massive mimo systems"
    - "the interplay between massive mimo and underlaid d2d networking"
    - "a survey on device to device communication in cellular networks"
    - "massive mimo for next generation wireless systems"
    - "what will 5g be"

Connected through hyperedge HE-2 (induced by source paper "tutorial on uav a blue sky view on wireless communication"):
  with members:
    - "cellular connectivity for uavs network modeling performance analysis and design guidelines"
    - "energy constrained uav trajectory design for ground node localization"
    - "comp in the sky uav placement and movement optimization for multi user communications"
    - "key technologies and system trade offs for detection and localization of amateur drones"
    - "the sky is not the limit lte for unmanned aerial vehicles"
    - "aerial anchors positioning for reliable rss based outdoor localization in urban environments"
    - "an overview of 3gpp release 15 study on enhanced lte support for connected drones"
    - "ultra reliable uav communication using altitude and cooperation diversity"

Connected through hyperedge HE-3 (induced by source paper "spectral and energy efficiency of uplink d2d underlaid massive mimo cellular networks"):
  with members:
    - "performance analysis of mixed adc massive mimo systems over rician fading channels"
    - "on the spectral efficiency of massive mimo systems with low resolution adcs"
    - "user association in 5g networks a survey and an outlook"
    - "mode selection resource allocation and power control for d2d enabled two tier cellular network"
    - "secure communications in millimeter wave ad hoc networks"
    - "deploying dense networks for maximal energy efficiency small cells meet massive mimo"
    - "the interplay between massive mimo and underlaid d2d networking"
    - "large scale mimo versus network mimo for multicell interference mitigation"

Connected through hyperedge HE-4 (induced by source paper "uplink performance analysis of a drone cell in a random field of ground interferers"):
  with members:
    - "reshaping cellular networks for the sky the major factors and feasibility"
    - "modeling and analysis of cellular networks using stochastic geometry a tutorial"
    - "coexistence of terrestrial and aerial users in cellular networks"
    - "coverage maximization for a poisson field of drone cells"
    - "wireless communications with unmanned aerial vehicles opportunities and challenges"
    - "drone small cells in the clouds design deployment and performance analysis"

Connected through hyperedge HE-5 (induced by source paper "unmanned aerial vehicle with underlaid device to device communications performance and tradeoffs"):
  with members:
    - "optimal transport theory for power efficient deployment of unmanned aerial vehicles"
    - "modeling and performance analysis of clustered device to device networks"
    - "drone small cells in the clouds design deployment and performance analysis"
    - "wide area wireless communication challenges for the internet of things"
    - "the interplay between massive mimo and underlaid d2d networking"
    - "power control for d2d underlaid cellular networks modeling algorithms and analysis"

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)