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: "principles of physical layer security in multiuser wireless networks a survey"
  Abstract: This paper provides a comprehensive review of the domain of physical layer security in multiuser wireless networks. The essential premise of physical layer security is to enable the exchange of confidential messages over a wireless medium in the presence of unauthorized eavesdroppers, without relying on higher-layer encryption. This can be achieved primarily in two ways: without the need for a secret key by intelligently designing transmit coding strategies, or by exploiting the wireless communication medium to develop secret keys over public channels. The survey begins with an overview of the foundations dating back to the pioneering work of Shannon and Wyner on information-theoretic security. We then describe the evolution of secure transmission strategies from point-to-point channels to multiple-antenna systems, followed by generalizations to multiuser broadcast, multiple-access, interference, and relay networks. Secret-key generation and establishment protocols based on physical layer mechanisms are subsequently covered. Approaches for secrecy based on channel coding design are then examined, along with a description of inter-disciplinary approaches based on game theory and stochastic geometry. The associated problem of physical layer message authentication is also briefly introduced. The survey concludes with observations on potential research directions in this area.

Connected through hyperedge HE-1 (induced by source paper "angle aware user cooperation for secure massive mimo in rician fading channel"):
  with members:
    - "machine intelligence at the edge with learning centric power allocation"
    - "robust and secure wireless communications via intelligent reflecting surfaces"
    - "vulnerabilities of massive mimo systems to pilot contamination attacks"
    - "resource allocation for secure irs assisted multiuser miso systems"
    - "physical layer security in uav systems challenges and opportunities"
    - "intelligent reflecting surface enhanced wireless network via joint active and passive beamforming"
    - "on low resolution adcs in practical 5g millimeter wave massive mimo systems"
    - "a survey of physical layer security techniques for 5g wireless networks and challenges ahead"

Connected through hyperedge HE-2 (induced by source paper "physical layer security in the finite blocklength regime over fading channels"):
  with members:
    - "secure and energy efficient transmissions in cache enabled heterogeneous cellular networks performance analysis and optimization"
    - "a survey of physical layer security techniques for 5g wireless networks and challenges ahead"
    - "safeguarding decentralized wireless networks using full duplex jamming receivers"
    - "artificial noise aided secure transmission in large scale spectrum sharing networks"
    - "on the spectral efficiency and security enhancements of noma assisted multicast unicast streaming"
    - "finite blocklength bounds for wiretap channels"
    - "a survey on wireless security technical challenges recent advances and future trends"
    - "enhancing the physical layer security of non orthogonal multiple access in large scale networks"

Connected through hyperedge HE-3 (induced by source paper "secure status updates under eavesdropping age of information based physical layer security metrics"):
  with members:
    - "age of information dependent random access for massive iot networks"
    - "a dynamic jamming game for real time status updates"

Connected through hyperedge HE-4 (induced by source paper "receive antenna selection for secure pre coding aided spatial modulation"):
  with members:
    - "two high performance schemes of transmit antenna selection for secure spatial modulation"

Connected through hyperedge HE-5 (induced by source paper "interplay between noma and other emerging technologies a survey"):
  with members:
    - "secure relaying in non orthogonal multiple access trusted and untrusted scenarios"
    - "securing downlink massive mimo noma networks with artificial noise"
    - "lens based millimeter wave reconfigurable antenna noma"
    - "what role can noma play in massive mimo"
    - "noma an information theoretic perspective"
    - "joint power and time allocation for noma mec offloading"
    - "multi beam noma for hybrid mmwave systems"
    - "exploiting full half duplex user relaying in noma systems"

Connected through hyperedge HE-6 (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-7 (induced by source paper "secure communications in a unified non orthogonal multiple access framework"):
  with members:
    - "exploiting full half duplex user relaying in noma systems"
    - "user association and resource allocation in unified noma enabled heterogeneous ultra dense networks"
    - "securing downlink non orthogonal multiple access systems by trusted relays"
    - "a unified framework for non orthogonal multiple access"
    - "edge computing aware noma for 5g networks"
    - "impact of non orthogonal multiple access on the offloading of mobile edge computing"
    - "secure communications in noma system subcarrier assignment and power allocation"
    - "performance analysis of noma with fixed gain relaying over nakagami m fading channels"

Connected through hyperedge HE-8 (induced by source paper "optimal downlink transmission for cell free swipt massive mimo systems with active eavesdropping"):
  with members:
    - "ubiquitous cell free massive mimo communications"
    - "cell free massive mimo networks optimal power control against active eavesdropping"
    - "spectral and energy efficiency of cell free massive mimo systems with hardware impairments"
    - "on the total energy efficiency of cell free massive mimo"
    - "energy efficiency in cell free massive mimo with zero forcing precoding design"
    - "secrecy and energy efficiency in massive mimo aided heterogeneous c ran a new look at interference"
    - "cell free massive mimo versus small cells"
    - "wireless power transfer in massive mimo aided hetnets with user association"

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)