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: "physical layer security in downlink multi antenna cellular networks"
  Abstract: In this paper, we study physical layer security for the downlink of cellular networks, where the confidential messages transmitted to each mobile user can be eavesdropped by both; 1) the other users in the same cell and 2) the users in the other cells. The locations of base stations and mobile users are modeled as two independent two-dimensional Poisson point processes. Using the proposed model, we analyze the secrecy rates achievable by regularized channel inversion (RCI) precoding by performing a large-system analysis that combines tools from stochastic geometry and random matrix theory. We obtain approximations for the probability of secrecy outage and the mean secrecy rate, and characterize regimes where RCI precoding achieves a non-zero secrecy rate. We find that unlike isolated cells, if one treats interference as noise, the secrecy rate in a cellular network does not grow monotonically with the transmit power, and the network tends to be in secrecy outage if the transmit power grows unbounded. Furthermore, we show that there is an optimal value for the base station deployment density that maximizes the secrecy rate, and this value is a decreasing function of the transmit power.

Connected through hyperedge HE-1 (induced by source paper "secure massive mimo communication with low resolution dacs"):
  with members:
    - "optimal multiuser loading in quantized massive mimo under spatially correlated channels"
    - "mimo channel information feedback using deep recurrent network"
    - "quantized constant envelope precoding with psk and qam signaling"
    - "on performance of quantized transceiver in multiuser massive mimo downlinks"
    - "spectral and energy efficiency of multi pair massive mimo relay network with hybrid processing"
    - "power efficient and secure wpcns with hardware impairments and non linear eh circuit"
    - "a tractable framework for performance analysis of dense multi antenna networks"
    - "analysis of one bit quantized precoding for the multiuser massive mimo downlink"

Connected through hyperedge HE-2 (induced by source paper "threats protection and attribution of cyber attacks on critical infrastructures"):
  with members:
    - "developing cyber peacekeeping observation monitoring and reporting"

Connected through hyperedge HE-3 (induced by source paper "toward a realistic assessment of multiple antenna hcns residual additive transceiver hardware impairments and channel aging"):
  with members:
    - "impact of general channel aging conditions on the downlink performance of massive mimo"
    - "performance of massive mimo uplink with zero forcing receivers under delayed channels"
    - "cell edge aware precoding for downlink massive mimo cellular networks"
    - "mitigation of phase noise in massive mimo systems a rate splitting approach"
    - "rate splitting to mitigate residual transceiver hardware impairments in massive mimo systems"
    - "analysis and design of secure massive mimo systems in the presence of hardware impairments"
    - "downlink mimo hcns with residual transceiver hardware impairments"
    - "sum rate and power scaling of massive mimo systems with channel aging"

Connected through hyperedge HE-4 (induced by source paper "cell edge aware precoding for downlink massive mimo cellular networks"):
  with members:
    - "distributed optimization of hierarchical small cell networks a gnep framework"
    - "massive mimo ten myths and one critical question"
    - "operating massive mimo in unlicensed bands for enhanced coexistence and spatial reuse"
    - "energy efficient design of mimo heterogeneous networks with wireless backhaul"
    - "a stochastic geometry framework for analyzing pairwise cooperative cellular networks"
    - "three practical aspects of massive mimo intermittent user activity pilot synchronism and asymmetric deployment"
    - "fractional pilot reuse in massive mimo systems"
    - "a tractable model for noncoherent joint transmission base station cooperation"

Connected through hyperedge HE-5 (induced by source paper "coexistence of rf powered iot and a primary wireless network with secrecy guard zones"):
  with members:
    - "power allocation for secure swipt systems with wireless powered cooperative jamming"
    - "secrecy outage analysis for downlink transmissions in the presence of randomly located eavesdroppers"
    - "modeling and analysis of cellular networks using stochastic geometry a tutorial"
    - "tight lower bounds on the contact distance distribution in poisson hole process"
    - "stochastic geometry based comparison of secrecy enhancement techniques in d2d networks"
    - "a primer on cellular network analysis using stochastic geometry"
    - "spatio temporal interference correlation and joint coverage in cellular networks"
    - "mimo wiretap channel under receiver side power constraints with applications to wireless power transfer and cognitive radio"

Connected through hyperedge HE-6 (induced by source paper "physical layer security in heterogeneous networks with jammer selection and full duplex users"):
  with members:
    - "exploiting full duplex receivers for achieving secret communications in multiuser miso networks"
    - "power allocation for secure swipt systems with wireless powered cooperative jamming"
    - "hybrid duplex switching in heterogeneous networks"
    - "opportunistic jamming for enhancing security stochastic geometry modeling and analysis"
    - "physical layer security in millimeter wave cellular networks"
    - "a survey on wireless security technical challenges recent advances and future trends"
    - "physical layer security in heterogeneous cellular networks"
    - "secure communication in uplink transmissions user selection and multiuser secrecy gain"

Connected through hyperedge HE-7 (induced by source paper "stochastic geometry based comparison of secrecy enhancement techniques in d2d networks"):
  with members:
    - "modeling and performance analysis of clustered device to device networks"
    - "d2d enhanced heterogeneous cellular networks with dynamic tdd"
    - "cognitive and energy harvesting based d2d communication in cellular networks stochastic geometry modeling and analysis"
    - "rethinking the secrecy outage formulation a secure transmission design perspective"
    - "on the throughput cost of physical layer security in decentralized wireless networks"
    - "secure transmission with artificial noise over fading channels achievable rate and optimal power allocation"
    - "on the throughput of secure hybrid arq protocols for gaussian block fading channels"

Connected through hyperedge HE-8 (induced by source paper "secure communications in millimeter wave ad hoc networks"):
  with members:
    - "secrecy and energy efficiency in massive mimo aided heterogeneous c ran a new look at interference"
    - "artificial noise aided secure transmission in large scale spectrum sharing networks"
    - "performance analysis of outdoor mmwave ad hoc networks"
    - "physical layer security in millimeter wave cellular networks"
    - "physical layer security in heterogeneous cellular networks"
    - "tractable resource management with uplink decoupled millimeter wave overlay in ultra dense cellular networks"
    - "physical layer security in three tier wireless sensor networks a stochastic geometry approach"
    - "secrecy transmit beamforming for heterogeneous 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)