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: "directional modulation via symbol level precoding a way to enhance security"
  Abstract: Wireless communication provides a wide coverage at the cost of exposing information to unintended users. As an information-theoretic paradigm, secrecy rate derives bounds for secure transmission when the channel to the eavesdropper is known. However, such bounds are shown to be restrictive in practice and may require exploitation of specialized coding schemes. In this paper, we employ the concept of directional modulation and follow a signal processing approach to enhance the security of multiuser multi-input multioutput (MIMO) communication systems when a multiantenna eavesdropper is present. Security enhancement is accomplished by increasing the symbol error rate at the eavesdropper. Unlike the information-theoretic secrecy rate paradigm, we assume that the legitimate transmitter is not aware of its channel to the eavesdropper, which is a more realistic assumption. We examine the applicability of MIMO receiving algorithms at the eavesdropper. Using the channel knowledge and the intended symbols for the users, we design security enhancing symbol-level precoders for different transmitter and eavesdropper antenna configurations. We transform each design problem to a linearly constrained quadratic program and propose two solutions, namely the iterative algorithm and one based on nonnegative least squares, at each scenario for a computationally efficient modulation. Simulation results verify the analysis and show that the designed precoders outperform the benchmark scheme in terms of both power efficiency and security enhancement.

Connected through hyperedge HE-1 (induced by source paper "rethinking secure precoding via interference exploitation a smart eavesdropper perspective"):
  with members:
    - "quantized constant envelope precoding with psk and qam signaling"
    - "linear precoding of data and artificial noise in secure massive mimo systems"
    - "constructive interference based secure precoding a new dimension in physical layer security"
    - "power efficient resource allocation for full duplex radio distributed antenna networks"
    - "exploiting known interference as green signal power for downlink beamforming optimization"
    - "on secrecy rate analysis of mimo wiretap channels driven by finite alphabet input"
    - "outage constrained robust transmit optimization for multiuser miso downlinks tractable approximations by conic optimization"
    - "secure transmission with artificial noise over fading channels achievable rate and optimal power allocation"

Connected through hyperedge HE-2 (induced by source paper "an overview of physical layer security with finite alphabet signaling"):
  with members:
    - "a survey of physical layer security techniques for 5g wireless networks and challenges ahead"
    - "physical layer cryptography through massive mimo"
    - "linear precoding of data and artificial noise in secure massive mimo systems"
    - "sum secrecy rate maximization for full duplex two way relay networks using alamouti based rank two beamforming"
    - "performance of lattice coset codes on universal software radio peripherals"
    - "secure m psk communication via directional modulation"
    - "finite blocklength bounds for wiretap channels"
    - "physical layer security in millimeter wave cellular networks"

Connected through hyperedge HE-3 (induced by source paper "power allocation strategy of maximizing secrecy rate for secure directional modulation"):
  with members:
    - "robust secure transmission of using main lobe integration based leakage beamforming in directional modulation mu mimo systems"
    - "artificial noise aided secure transmission in wiretap channels with transmitter side correlation"
    - "relay selection improves the security reliability trade off in cognitive radio systems"
    - "secure massive mimo transmission in the presence of an active eavesdropper"

Connected through hyperedge HE-4 (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"
    - "artificial noise aided secure transmission with directional modulation based on random frequency diverse arrays"
    - "spectral efficiency of mixed adc receivers for massive mimo systems"
    - "channel estimation and hybrid precoding for millimeter wave cellular systems"
    - "spatially sparse precoding in millimeter wave mimo systems"

Connected through hyperedge HE-5 (induced by source paper "secure precise wireless transmission with random subcarrier selection based directional modulation transmit antenna array"):
  with members:
    - "covert communication in wireless relay networks"
    - "symbol level and multicast precoding for multiuser multiantenna downlink a survey classification and challenges"
    - "the random frequency diverse array a new antenna structure for uncoupled direction range indication in active sensing"
    - "artificial noise aided secure transmission in wiretap channels with transmitter side correlation"
    - "location based beamforming for enhancing secrecy in rician wiretap channels"
    - "improving physical layer security in wireless communications using diversity techniques"
    - "relay selection improves the security reliability trade off in cognitive radio systems"
    - "optimization of code rates in sisome wiretap channels"

Connected through hyperedge HE-6 (induced by source paper "transmit precoding for interference exploitation in the underlay cognitive radio z channel"):
  with members:
    - "energy efficient symbol level precoding in multiuser miso based on relaxed detection region"
    - "secure m psk communication via directional modulation"
    - "constructive interference through symbol level precoding for multi level modulation"
    - "constructive multiuser interference in symbol level precoding for the miso downlink channel"
    - "exploiting known interference as green signal power for downlink beamforming optimization"
    - "rethinking the role of interference in wireless networks"
    - "dynamic resource allocation in cognitive radio networks"
    - "training and feedback optimization for multiuser mimo downlink"

Connected through hyperedge HE-7 (induced by source paper "gpi based secrecy rate maximization beamforming scheme for wireless transmission with an aided directional modulation"):
  with members:
    - "robust secure transmission of using main lobe integration based leakage beamforming in directional modulation mu mimo systems"
    - "symbol level and multicast precoding for multiuser multiantenna downlink a survey classification and challenges"
    - "secure precise wireless transmission with random subcarrier selection based directional modulation transmit antenna array"
    - "artificial noise aided secure transmission in wiretap channels with transmitter side correlation"
    - "secrecy transmit beamforming for heterogeneous networks"
    - "relay selection improves the security reliability trade off in cognitive radio systems"

Connected through hyperedge HE-8 (induced by source paper "m qam precoder design for mimo directional modulation transceivers"):
  with members:
    - "energy efficient symbol level precoding in multiuser miso based on relaxed detection region"
    - "constructive interference through symbol level precoding for multi level modulation"
    - "constructive multiuser interference in symbol level precoding for the miso downlink channel"
    - "exploiting known interference as green signal power for downlink beamforming optimization"
    - "single user beamforming in large scale miso systems with per antenna constant envelope constraints the doughnut channel"

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)