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: "securing massive mimo at the physical layer"
  Abstract: We consider a single-cell downlink massive MIMO system in the presence of attackers capable of jamming and eavesdropping. We show that, classical attacks of data jamming and eavesdropping can be simultaneously rendered useless. Specifically, we show that, without the need to use wiretap encoding, users achieve secure and reliable communication rate of which increases at the same speed as the rate achieved under no attack as the number of antennas grow. However, we introduce a new attack strategy that involves jamming pilot signals and eavesdropping in succession and show significant reductions in the achievable secrecy rate, even in the asymptotic regime in number of antennas. We develop counter strategies for this new attack in which we use secret key to encrypt the pilot sequence, rather than the data. We show that hiding the training signal assignments from the attacker enables the mobiles to achieve a secure degrees of freedom, identical to the one achieved under no attack.

Connected through hyperedge HE-1 (induced by source paper "downlink secrecy rate of one bit massive mimo system with active eavesdropping"):
  with members:
    - "robust designs of beamforming and power splitting for distributed antenna systems with wireless energy harvesting"
    - "secure massive mimo communication with low resolution dacs"
    - "on the uplink achievable rate for massive mimo with 1 bit adc and superimposed pilots"
    - "data aided secure massive mimo transmission with active eavesdropping"
    - "secure massive mimo systems with limited rf chains"
    - "secure transmission with large numbers of antennas and finite alphabet inputs"
    - "jamming resistant receivers for the massive mimo uplink"
    - "beamforming and power splitting designs for an aided secure multi user mimo swipt systems"

Connected through hyperedge HE-2 (induced by source paper "jamming robust uplink transmission for spatially correlated massive mimo systems"):
  with members:
    - "jamming suppression in massive mimo systems"
    - "hardware distortion correlation has negligible impact on ul massive mimo spectral efficiency"
    - "cell free massive mimo networks optimal power control against active eavesdropping"
    - "multiple antennas secure transmission under pilot spoofing and jamming attack"
    - "jamming detection in massive mimo systems"
    - "subverting massive mimo by smart jamming"
    - "secure massive mimo transmission with an active eavesdropper"
    - "physical layer security for massive mimo an overview on passive eavesdropping and active attacks"

Connected through hyperedge HE-3 (induced by source paper "data aided secure massive mimo transmission under the pilot contamination attack"):
  with members:
    - "a survey of physical layer security techniques for 5g wireless networks and challenges ahead"
    - "pilot spoofing attack by multiple eavesdroppers"
    - "multiple antennas secure transmission under pilot spoofing and jamming attack"
    - "secure transmission with large numbers of antennas and finite alphabet inputs"
    - "massive mimo pilot decontamination and channel interpolation via wideband sparse channel estimation"
    - "analysis and design of secure massive mimo systems in the presence of hardware impairments"
    - "performance limits of massive mimo systems based on bayes optimal inference"
    - "secure massive mimo transmission with an active eavesdropper"

Connected through hyperedge HE-4 (induced by source paper "jamming suppression in massive mimo systems"):
  with members:
    - "efficient dsp and circuit architectures for massive mimo state of the art and future directions"
    - "multiple antennas secure transmission under pilot spoofing and jamming attack"
    - "jamming detection in massive mimo systems"
    - "energy and spectral efficiency of very large multiuser mimo systems"

Connected through hyperedge HE-5 (induced by source paper "data aided secure massive mimo transmission with active eavesdropping"):
  with members:
    - "secure transmission with large numbers of antennas and finite alphabet inputs"
    - "analysis and design of secure massive mimo systems in the presence of hardware impairments"
    - "performance limits of massive mimo systems based on bayes optimal inference"
    - "secure massive mimo transmission with an active eavesdropper"
    - "large scale mimo relaying techniques for physical layer security af or df"
    - "secret key agreement with large antenna arrays under the pilot contamination attack"
    - "what will 5g be"
    - "blind pilot decontamination"

Connected through hyperedge HE-6 (induced by source paper "pilot spoofing attack by multiple eavesdroppers"):
  with members:
    - "admm based fast algorithm for multi group multicast beamforming in large scale wireless systems"
    - "impact of artificial noise on cellular networks a stochastic geometry approach"
    - "an algorithm for global maximization of secrecy rates in gaussian mimo wiretap channels"
    - "secure massive mimo transmission with an active eavesdropper"
    - "physical layer security in massive mimo"
    - "secret key agreement with large antenna arrays under the pilot contamination attack"
    - "secure communication over parallel relay channel"
    - "robust secure transmission in miso channels based on worst case optimization"

Connected through hyperedge HE-7 (induced by source paper "multiple antennas secure transmission under pilot spoofing and jamming attack"):
  with members:
    - "secure transmission with large numbers of antennas and finite alphabet inputs"
    - "jamming detection in massive mimo systems"
    - "linear precoding of data and artificial noise in secure massive mimo systems"
    - "physical layer security in heterogeneous cellular networks"
    - "massive mimo pilot retransmission strategies for robustification against jamming"
    - "subverting massive mimo by smart jamming"
    - "secure massive mimo transmission with an active eavesdropper"
    - "pilot reuse for massive mimo transmission over spatially correlated rayleigh fading channels"

Connected through hyperedge HE-8 (induced by source paper "jamming resistant receivers for the massive mimo uplink"):
  with members:
    - "jamming resistant receivers for massive mimo"
    - "pilot contamination is not a fundamental asymptotic limitation in massive mimo"
    - "subverting massive mimo by smart jamming"
    - "secure massive mimo transmission with an active eavesdropper"
    - "jamming aided secure communication in massive mimo rician channels"
    - "physical layer security for massive mimo an overview on passive eavesdropping and active attacks"
    - "worst case jamming on mimo gaussian channels"
    - "interference reduction in multi cell massive mimo systems i large scale fading precoding and decoding"

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)