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: "optimal power allocation for artificial noise under imperfect csi against spatially random eavesdroppers"
  Abstract: In this paper, we study the secure multiantenna transmission with artificial noise (AN) under imperfect channel state information (CSI) in the presence of spatially randomly distributed eavesdroppers. We derive the optimal solutions of the power allocation between the information signal and the AN for minimizing the secrecy outage probability (SOP) under a target secrecy rate and for maximizing the secrecy rate under an SOP constraint, respectively. Moreover, we provide an interesting insight that channel estimation error affects the optimal power allocation strategy in opposite ways for the two given objectives. When the estimation error increases, more power should be allocated to the information signal if we aim to decrease the rate-constrained SOP, whereas more power should be allocated to the AN if we aim to increase the SOP-constrained secrecy rate.

Connected through hyperedge HE-1 (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"
    - "artificial noise aided secure transmission with directional modulation based on random frequency diverse arrays"
    - "an overview of sustainable green 5g networks"
    - "secure massive mimo transmission in the presence of an active eavesdropper"

Connected through hyperedge HE-2 (induced by source paper "safeguarding decentralized wireless networks using full duplex jamming receivers"):
  with members:
    - "physical layer security in heterogeneous cellular networks"
    - "throughput analysis for full duplex wireless networks with imperfect self interference cancellation"
    - "principles of physical layer security in multiuser wireless networks a survey"
    - "improving physical layer secrecy using full duplex jamming receivers"
    - "enhancing secrecy with multi antenna transmission in wireless ad hoc networks"
    - "in band full duplex wireless challenges and opportunities"
    - "experiment driven characterization of full duplex wireless systems"
    - "on the throughput cost of physical layer security in decentralized wireless networks"

Connected through hyperedge HE-3 (induced by source paper "physical layer security in wireless ad hoc networks under a hybrid full half duplex receiver deployment strategy"):
  with members:
    - "safeguarding decentralized wireless networks using full duplex jamming receivers"
    - "physical layer security in millimeter wave cellular networks"
    - "physical layer security in heterogeneous cellular networks"
    - "hybrid full half duplex system analysis in heterogeneous wireless networks"
    - "improving physical layer secrecy using full duplex jamming receivers"
    - "enhancing secrecy with multi antenna transmission in wireless ad hoc networks"
    - "energy efficient optimization for physical layer security in multi antenna downlink networks with qos guarantee"
    - "on the throughput cost of physical layer security in decentralized wireless networks"

Connected through hyperedge HE-4 (induced by source paper "physical layer security in heterogeneous cellular networks"):
  with members:
    - "secrecy transmit beamforming for heterogeneous networks"
    - "physical layer security in downlink multi antenna cellular networks"
    - "principles of physical layer security in multiuser wireless networks a survey"
    - "throughput and energy efficiency analysis of small cell networks with multi antenna base stations"
    - "enhancing secrecy with multi antenna transmission in wireless ad hoc networks"
    - "physical layer security in cellular networks a stochastic geometry approach"
    - "on the design of artificial noise aided secure multi antenna transmission in slow fading channels"
    - "heterogeneous cellular networks with flexible cell association a comprehensive downlink sinr analysis"

Connected through hyperedge HE-5 (induced by source paper "impact of artificial noise on cellular networks a stochastic geometry approach"):
  with members:
    - "d2d enhanced heterogeneous cellular networks with dynamic tdd"
    - "what will 5g be"
    - "physical layer security in downlink multi antenna cellular networks"
    - "throughput and energy efficiency analysis of small cell networks with multi antenna base stations"
    - "enhancing secrecy with multi antenna transmission in wireless ad hoc networks"
    - "coordinated beamforming for multiuser miso interference channel under rate outage constraints"
    - "physical layer security in cellular networks a stochastic geometry approach"
    - "on the design of artificial noise aided secure multi antenna transmission in slow fading channels"

Connected through hyperedge HE-6 (induced by source paper "multi antenna transmission in downlink heterogeneous cellular networks under a threshold based mobile association policy"):
  with members:
    - "success probability and area spectral efficiency in multiuser mimo hetnets"
    - "optimal cell load and throughput in green small cell networks with generalized cell association"
    - "what will 5g be"
    - "massive mimo meets hetnet interference coordination through spatial blanking"
    - "throughput and energy efficiency analysis of small cell networks with multi antenna base stations"
    - "downlink mimo hetnets modeling ordering results and performance analysis"
    - "offloading in heterogeneous networks modeling analysis and design insights"
    - "load aware modeling and analysis of heterogeneous cellular networks"

Connected through hyperedge HE-7 (induced by source paper "physical layer security in millimeter wave cellular networks"):
  with members:
    - "performance analysis of outdoor mmwave ad hoc networks"
    - "physical layer security in heterogeneous cellular networks"
    - "stochastic geometry modeling and analysis of multi tier millimeter wave cellular networks"
    - "tractable model for rate in self backhauled millimeter wave cellular networks"
    - "coverage and rate analysis for millimeter wave cellular networks"
    - "millimeter wave cellular wireless networks potentials and challenges"
    - "physical layer security in downlink multi antenna cellular networks"
    - "principles of physical layer security in multiuser wireless networks a survey"

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)