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: "capacity characterization for intelligent reflecting surface aided mimo communication"
  Abstract: Intelligent reflecting surface (IRS) is a promising solution to enhance the wireless communication capacity both cost-effectively and energy-efficiently, by properly altering the signal propagation via tuning a large number of passive reflecting units. In this paper, we aim to characterize the fundamental capacity limit of IRS-aided point-to-point multiple-input multiple-output (MIMO) communication systems with multi-antenna transmitter and receiver in general, by jointly optimizing the IRS reflection coefficients and the MIMO transmit covariance matrix. First, we consider narrowband transmission under frequency-flat fading channels, and develop an efficient alternating optimization algorithm to find a locally optimal solution by iteratively optimizing the transmit covariance matrix or one of the reflection coefficients with the others being fixed. Next, we consider capacity maximization for broadband transmission in a general MIMO orthogonal frequency division multiplexing (OFDM) system under frequency-selective fading channels, where transmit covariance matrices can be optimized for different subcarriers while only one common set of IRS reflection coefficients can be designed to cater to all subcarriers. To tackle this more challenging problem, we propose a new alternating optimization algorithm based on convex relaxation to find a high-quality suboptimal solution. Numerical results show that our proposed algorithms achieve substantially increased capacity compared to traditional MIMO channels without the IRS, and also outperform various benchmark schemes. In particular, it is shown that with the proposed algorithms, various key parameters of the IRS-aided MIMO channel such as channel total power, rank, and condition number can be significantly improved for capacity enhancement.

Connected through hyperedge HE-1 (induced by source paper "mimo noma networks relying on reconfigurable intelligent surface a signal cancellation based design"):
  with members:
    - "intelligent reflecting surface assisted multiple access with user pairing noma or oma"
    - "enabling panoramic full angle reflection via aerial intelligent reflecting surface"
    - "performance analysis of intelligent reflecting surface assisted noma networks"
    - "miso wireless communication systems via intelligent reflecting surfaces"
    - "large intelligent surface antennas lisa making reflective radios smart"
    - "reflection probability in wireless networks with metasurface coated environmental objects an approach based on random spatial processes"
    - "channel capacity optimization using reconfigurable intelligent surfaces in indoor mmwave environments"
    - "beamforming optimization for wireless network aided by intelligent reflecting surface with discrete phase shifts"

Connected through hyperedge HE-2 (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"
    - "power efficient irs assisted noma"
    - "intelligent reflecting surface meets ofdm protocol design and rate maximization"
    - "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-3 (induced by source paper "intelligent reflecting surface assisted secure wireless communications with multiple transmit and multiple receive antennas"):
  with members:
    - "secure wireless communication via intelligent reflecting surface"
    - "a survey of optimization approaches for wireless physical layer security"
    - "resource allocation for secure irs assisted multiuser miso systems"
    - "secure transmission strategy for intelligent reflecting surface enhanced wireless system"
    - "enabling secure wireless communications via intelligent reflecting surfaces"
    - "indoor signal focusing with deep learning designed reconfigurable intelligent surfaces"
    - "intelligent reflecting surface assisted non orthogonal multiple access"
    - "weighted sum power maximization for intelligent reflecting surface aided swipt"

Connected through hyperedge HE-4 (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"
    - "progressive channel estimation and passive beamforming for intelligent reflecting surface with discrete phase shifts"
    - "intelligent reflecting surface meets ofdm protocol design and rate maximization"

Connected through hyperedge HE-5 (induced by source paper "capacity and optimal resource allocation for irs assisted multi user communication systems"):
  with members:
    - "large intelligent surface antennas lisa making reflective radios smart"
    - "robust and secure wireless communications via intelligent reflecting surfaces"
    - "power efficient irs assisted noma"
    - "intelligent reflecting surface assisted non orthogonal multiple access"
    - "a vision of 6g wireless systems applications trends technologies and open research problems"
    - "a simple design of irs noma transmission"
    - "irs enhanced ofdma joint resource allocation and passive beamforming optimization"
    - "mimo assisted networks relying on large intelligent surfaces a stochastic geometry model"

Connected through hyperedge HE-6 (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"
    - "intelligent reflecting surface meets ofdm protocol design and rate maximization"
    - "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-7 (induced by source paper "resource allocation for irs assisted full duplex cognitive radio systems"):
  with members:
    - "resource allocation for intelligent reflecting surface assisted cognitive radio networks"
    - "miso wireless communication systems via intelligent reflecting surfaces"
    - "resource allocation for secure irs assisted multiuser miso systems"
    - "enabling secure wireless communications via intelligent reflecting surfaces"
    - "channel estimation for intelligent reflecting surface assisted multiuser communications"
    - "multiple antenna technologies for beyond 5g"
    - "towards smart and reconfigurable environment intelligent reflecting surface aided wireless network"
    - "intelligent reflecting surface enhanced wireless network via joint active and passive beamforming"

Connected through hyperedge HE-8 (induced by source paper "optimal beamforming for miso communications via intelligent reflecting surfaces"):
  with members:
    - "miso wireless communication systems via intelligent reflecting surfaces"
    - "robust and secure wireless communications via intelligent reflecting surfaces"
    - "resource allocation for secure irs assisted multiuser miso systems"
    - "enabling secure wireless communications via intelligent reflecting surfaces"
    - "channel estimation for intelligent reflecting surface assisted multiuser communications"
    - "multiple antenna technologies for beyond 5g"
    - "towards smart and reconfigurable environment intelligent reflecting surface aided wireless network"
    - "intelligent reflecting surface enhanced wireless network via joint active and passive beamforming"

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)