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: "intelligent reflecting surface meets ofdm protocol design and rate maximization"
  Abstract: Intelligent reflecting surface (IRS) is a promising new technology for achieving both spectrum and energy efficient wireless communication systems in the future. However, existing works on IRS mainly consider frequency-flat channels and assume perfect knowledge of channel state information (CSI) at the transmitter. Motivated by this, in this paper we study an IRS-enhanced orthogonal frequency division multiplexing (OFDM) system under frequency-selective channels and propose a practical transmission protocol with channel estimation. First, to reduce the overhead in channel training and estimation and to exploit the channel spatial correlation, we propose a novel IRS elements grouping method, where each group consists of a set of adjacent IRS elements that share a common reflection coefficient. Based on this grouping method, we propose a practical transmission protocol where only the combined channel of each group needs to be estimated, thus substantially reducing the training overhead. Next, with any given grouping and estimated CSI, we formulate the problem to maximize the achievable rate by jointly optimizing the transmit power allocation and the IRS passive array reflection coefficients. Although the formulated problem is non-convex and thus difficult to solve, we propose an efficient algorithm to obtain a high-quality suboptimal solution for it, by alternately optimizing the power allocation and the passive array coefficients in an iterative manner, along with a customized method for the initialization. Simulation results show that the proposed design significantly improves the OFDM link rate performance as compared to the case without using IRS. Moreover, it is shown that there exists an optimal size for IRS elements grouping which achieves the maximum achievable rate due to the trade-off between the training overhead and IRS passive beamforming flexibility.

Connected through hyperedge HE-1 (induced by source paper "resource allocation in intelligent reflecting surface assisted noma systems"):
  with members:
    - "joint active and passive beamforming optimization for intelligent reflecting surface assisted swipt under qos constraints"
    - "capacity characterization for intelligent reflecting surface aided mimo communication"
    - "power efficient irs assisted noma"
    - "intelligent reflecting surface assisted non orthogonal multiple access"
    - "intelligent reflecting surface design for mimo system by maximizing sum path gains"
    - "a simple design of irs noma transmission"
    - "towards smart radio environment for wireless communications via intelligent reflecting surfaces a comprehensive survey"
    - "joint beamforming design in multi cluster miso noma intelligent reflecting surface aided downlink communication networks"

Connected through hyperedge HE-2 (induced by source paper "intelligent reflecting surface assisted multi user ofdma channel estimation and training design"):
  with members:
    - "intelligent reflecting surface assisted multiple access with user pairing noma or oma"
    - "parallel factor decomposition channel estimation in ris assisted multi user miso communication"
    - "intelligent reflecting surface with discrete phase shifts channel estimation and passive beamforming"
    - "secure wireless communication via intelligent reflecting surface"
    - "cascaded channel estimation for large intelligent metasurface assisted massive mimo"
    - "channel estimation for intelligent reflecting surface assisted multiuser communications framework algorithms and analysis"
    - "capacity characterization for intelligent reflecting surface aided mimo communication"
    - "progressive channel estimation and passive beamforming for intelligent reflecting surface with discrete phase shifts"

Connected through hyperedge HE-3 (induced by source paper "joint power control and passive beamforming in irs assisted spectrum sharing"):
  with members:
    - "intelligent reflecting surface assisted multiple access with user pairing noma or oma"
    - "joint active and passive beamforming optimization for intelligent reflecting surface assisted swipt under qos constraints"
    - "holographic mimo surfaces for 6g wireless networks opportunities challenges and trends"
    - "secure wireless communication via intelligent reflecting surface"
    - "capacity characterization for intelligent reflecting surface aided mimo communication"
    - "enabling secure wireless communications via intelligent reflecting surfaces"
    - "intelligent reflecting surface assisted secrecy communication is artificial noise helpful or not"
    - "beamforming optimization for wireless network aided by intelligent reflecting surface with discrete phase shifts"

Connected through hyperedge HE-4 (induced by source paper "millimeter wave communications with an intelligent reflector performance optimization and distributional reinforcement learning"):
  with members:
    - "reflections in the sky millimeter wave communication with uav carried intelligent reflectors"
    - "reflect and transmit array antennas for scalable and energy efficient mmwave massive mimo"
    - "intelligent reflecting and transmitting surface aided millimeter wave massive mimo"
    - "a vision of 6g wireless systems applications trends technologies and open research problems"
    - "enabling large intelligent surfaces with compressive sensing and deep learning"
    - "performance analysis of large intelligent surfaces liss uplink spectral efficiency and pilot training"
    - "intelligent reflecting surface enhanced wireless network via joint active and passive beamforming"
    - "fractional programming for communication systems part i power control and beamforming"

Connected through hyperedge HE-5 (induced by source paper "intelligent reflecting surface assisted multiple access with user pairing noma or oma"):
  with members:
    - "beamforming optimization for wireless network aided by intelligent reflecting surface with discrete phase shifts"
    - "intelligent reflecting surface assisted non orthogonal multiple access"
    - "a simple design of irs noma transmission"
    - "towards smart and reconfigurable environment intelligent reflecting surface aided wireless network"
    - "joint beamforming design in multi cluster miso noma intelligent reflecting surface aided downlink communication networks"
    - "intelligent reflecting surface enhanced ofdm channel estimation and reflection optimization"
    - "intelligent reflecting surface enhanced wireless network via joint active and passive beamforming"

Connected through hyperedge HE-6 (induced by source paper "intelligent reflecting surface aided multiple access capacity region and deployment strategy"):
  with members:
    - "intelligent reflecting surface versus decode and forward how large surfaces are needed to beat relaying"
    - "capacity characterization for intelligent reflecting surface aided mimo communication"
    - "towards smart and reconfigurable environment intelligent reflecting surface aided wireless network"
    - "intelligent reflecting surface enhanced ofdm channel estimation and reflection optimization"
    - "achievable rate maximization by passive intelligent mirrors"
    - "intelligent reflecting surface enhanced wireless network via joint active and passive beamforming"
    - "cooperative interference management with miso beamforming"

Connected through hyperedge HE-7 (induced by source paper "enabling panoramic full angle reflection via aerial intelligent reflecting surface"):
  with members:
    - "intelligent reflecting surface versus decode and forward how large surfaces are needed to beat relaying"
    - "achievable rate maximization by passive intelligent mirrors"
    - "intelligent reflecting surface enhanced wireless network via joint active and passive beamforming"
    - "large intelligent surface assisted wireless communication exploiting statistical csi"
    - "increasing indoor spectrum sharing capacity using smart reflect array"

Connected through hyperedge HE-8 (induced by source paper "channel estimation and hybrid beamforming for reconfigurable intelligent surfaces assisted thz communications"):
  with members:
    - "secure wireless communication via intelligent reflecting surface"
    - "capacity characterization for intelligent reflecting surface aided mimo communication"
    - "intelligent reflecting surface design for mimo system by maximizing sum path gains"
    - "channel estimation and transmission for intelligent reflecting surface assisted thz communications"
    - "energy efficient multi user miso communication using low resolution large intelligent surfaces"
    - "achievable rate maximization by passive intelligent mirrors"
    - "intelligent reflecting surface enhanced wireless network via joint active and passive beamforming"
    - "beyond massive mimo the potential of data transmission with large intelligent surfaces"

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)