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: "artificial noise aided secure transmission with directional modulation based on random frequency diverse arrays"
  Abstract: In this paper, we propose a novel directional modulation (DM) scheme based on random frequency diverse arrays with artificial noise (RFDA-DM-AN) to enhance physical layer security of wireless communications. Specifically, we first design the RFDA-DM-AN scheme by randomly allocating frequencies to transmit antennas, thereby achieving two-dimensionally (i.e., angle and range) secure transmissions, and outperforming the state-of-the-art one-dimensional (i.e., angle) phase array (PA) based DM scheme. Then we develop the closed-form expression of a lower bound on the ergodic secrecy capacity (ESC) of our RFDA-DM-AN scheme. Based on the theoretical lower bound derived, we further optimize the transmission power allocation between the useful signal and artificial noise (AN) in order to enhance the ESC. Simulation results show that 1) our RFDA-DM-AN scheme achieves a higher secrecy capacity than that of the PA based DM scheme, 2) the lower bound derived is shown to approach the ESC as the number of transmit antennas N increases and precisely matches the ESC when N is sufficiently large, and 3) the proposed optimum power allocation achieves the highest ESC compared with other power allocations in the RFDA-DM-AN.

Connected through hyperedge HE-1 (induced by source paper "covert transmission with a self sustained relay"):
  with members:
    - "achieving covert wireless communications using a full duplex receiver"
    - "multi hop routing in covert wireless networks"
    - "covert communication achieved by a greedy relay in wireless networks"
    - "wireless powered dense cellular networks how many small cells do we need"
    - "covert communication in fading channels under channel uncertainty"
    - "covert communications with a full duplex receiver over wireless fading channels"
    - "covert communication with finite blocklength in awgn channels"
    - "on covert communication with noise uncertainty"

Connected through hyperedge HE-2 (induced by source paper "energy efficient alternating iterative secure structure of maximizing secrecy rate for directional modulation networks"):
  with members:
    - "alternating iterative secure structure between beamforming and power allocation for uav aided directional modulation networks"
    - "robust secure transmission of using main lobe integration based leakage beamforming in directional modulation mu mimo systems"
    - "secure transmission with large numbers of antennas and finite alphabet inputs"
    - "artificial noise aided secure multicast precoding for directional modulation systems"
    - "low complexity and high resolution doa estimation for hybrid analog and digital massive mimo receive array"
    - "optimal power allocation for artificial noise under imperfect csi against spatially random eavesdroppers"
    - "an overview of sustainable green 5g networks"
    - "secure massive mimo transmission in the presence of an active eavesdropper"

Connected through hyperedge HE-3 (induced by source paper "two high performance amplitude beamforming schemes for secure precise communication and jamming with phase alignment"):
  with members:
    - "two high performance schemes of transmit antenna selection for secure spatial modulation"
    - "secure transmission with large numbers of antennas and finite alphabet inputs"
    - "artificial noise aided secure multicast precoding for directional modulation systems"
    - "interference alignment and soft space reuse based cooperative transmission for multi cell massive mimo networks"

Connected through hyperedge HE-4 (induced by source paper "covert wireless communications with channel inversion power control in rayleigh fading"):
  with members:
    - "gaussian signalling for covert communications"
    - "achieving covert wireless communications using a full duplex receiver"
    - "adaptive full duplex jamming receiver for secure d2d links in random networks"
    - "covert communication in wireless relay networks"
    - "covert communication achieved by a greedy relay in wireless networks"
    - "covert wireless communication with a poisson field of interferers"
    - "covert communication in fading channels under channel uncertainty"
    - "covert communications with a full duplex receiver over wireless fading channels"

Connected through hyperedge HE-5 (induced by source paper "alternating iterative secure structure between beamforming and power allocation for uav aided directional modulation networks"):
  with members:
    - "robust secure transmission of using main lobe integration based leakage beamforming in directional modulation mu mimo systems"
    - "secure transmission with large numbers of antennas and finite alphabet inputs"
    - "joint trajectory and communication design for multi uav enabled wireless networks"
    - "artificial noise aided secure multicast precoding for directional modulation systems"
    - "interference alignment and soft space reuse based cooperative transmission for multi cell massive mimo networks"
    - "low complexity and high resolution doa estimation for hybrid analog and digital massive mimo receive array"
    - "overcoming endurance issue uav enabled communications with proactive caching"
    - "energy efficient uav communication with trajectory optimization"

Connected through hyperedge HE-6 (induced by source paper "covert communication achieved by a greedy relay in wireless networks"):
  with members:
    - "covert communication in wireless relay networks"
    - "fundamental limits of covert communication over mimo awgn channel"
    - "covert communication in fading channels under channel uncertainty"
    - "covert communication with finite blocklength in awgn channels"
    - "on covert communication with noise uncertainty"
    - "fundamental limits of communication with low probability of detection"
    - "artificial noise aided secure transmission in large scale spectrum sharing networks"
    - "covert communication in the presence of an uninformed jammer"

Connected through hyperedge HE-7 (induced by source paper "covert communication in wireless relay networks"):
  with members:
    - "covert communication in fading channels under channel uncertainty"
    - "covert communication with finite blocklength in awgn channels"
    - "on covert communication with noise uncertainty"
    - "fundamental limits of communication with low probability of detection"
    - "covert communication over noisy channels a resolvability perspective"
    - "artificial noise aided secure transmission in wiretap channels with transmitter side correlation"
    - "lpd communication when the warden does not know when"
    - "reliable deniable communication hiding messages in noise"

Connected through hyperedge HE-8 (induced by source paper "low complexity and high resolution doa estimation for hybrid analog and digital massive mimo receive array"):
  with members:
    - "robust secure transmission of using main lobe integration based leakage beamforming in directional modulation mu mimo systems"
    - "a survey of multi objective optimization in wireless sensor networks metrics algorithms and open problems"
    - "alternating minimization algorithms for hybrid precoding in millimeter wave mimo systems"
    - "energy efficient uav communication with trajectory optimization"
    - "spectral efficiency of mixed adc receivers for massive mimo systems"
    - "directional modulation via symbol level precoding a way to enhance security"
    - "channel estimation and hybrid precoding for millimeter wave cellular systems"
    - "spatially sparse precoding in millimeter wave mimo systems"

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)