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: "user assignment with distributed large intelligent surface lis systems"
  Abstract: In this paper, we consider a wireless communication system where a large intelligent surface (LIS) is deployed comprising a number of small and distributed LIS-Units. Each LIS-Unit has a separate signal process unit (SPU) and is connected to a central process unit (CPU) that coordinates the behaviors of all the LIS-Units. With such a LIS system, we consider the user assignments both for sum-rate and minimal user-rate maximizations. That is, assuming $M$ LIS-Units deployed in the LIS system, the objective is to select $K$ ($K\!\leq\!M$) best LIS-Units to serve $K$ autonomous users simultaneously. Based on the nice property of effective inter-user interference suppression of the LIS-Units, the optimal user assignments can be effectively found through classical linear assignment problems (LAPs) defined on a bipartite graph. To be specific, the optimal user assignment for sum-rate and user-rate maximizations can be solved by linear sum assignment problem (LSAP) and linear bottleneck assignment problem (LBAP), respectively. The elements of the cost matrix are constructed based on the received signal strength (RSS) measured at each of the $M$ LIS-Units for all the $K$ users. Numerical results show that, the proposed user assignments are close to optimal user assignments both under line-of-sight (LoS) and scattering environments.

Connected through hyperedge HE-1 (induced by source paper "real time implementation aspects of large intelligent surfaces"):
  with members:
    - "energy efficient multi user miso communication using low resolution large intelligent surfaces"
    - "intelligent reflecting surface enhanced wireless network via joint active and passive beamforming"
    - "massive mimo in sub 6 ghz and mmwave physical practical and use case differences"
    - "capacity degradation with modeling hardware impairment in large intelligent surface"
    - "beyond massive mimo the potential of data transmission with large intelligent surfaces"
    - "beamforming optimization for intelligent reflecting surface with discrete phase shifts"
    - "reconfigurable intelligent surfaces for energy efficiency in wireless communication"
    - "intelligent reflecting surface enhanced wireless network joint active and passive beamforming design"

Connected through hyperedge HE-2 (induced by source paper "reconfigurable intelligent surface empowered 6g wireless communications challenges and opportunities"):
  with members:
    - "cascaded channel estimation for large intelligent metasurface assisted massive mimo"
    - "channel estimation for intelligent reflecting surface assisted multiuser communications"
    - "enabling large intelligent surfaces with compressive sensing and deep learning"
    - "the roadmap to 6g ai empowered wireless networks"
    - "intelligent reflecting surface enhanced wireless network via joint active and passive beamforming"
    - "reconfigurable intelligent surfaces for energy efficiency in wireless communication"
    - "large intelligent surface assisted wireless communication exploiting statistical csi"

Connected through hyperedge HE-3 (induced by source paper "asymptotic max min sinr analysis of reconfigurable intelligent surface assisted miso systems"):
  with members:
    - "intelligent reflecting surface versus decode and forward how large surfaces are needed to beat relaying"
    - "large intelligent surface antennas lisa making reflective radios smart"
    - "asymptotic analysis of rzf over double scattering channels with mmse estimation"
    - "rfocus practical beamforming for small devices"
    - "resource allocation for secure irs assisted multiuser miso systems"
    - "enabling secure wireless communications via intelligent reflecting surfaces"
    - "enabling large intelligent surfaces with compressive sensing and deep learning"
    - "mimo assisted networks relying on large intelligent surfaces a stochastic geometry model"

Connected through hyperedge HE-4 (induced by source paper "performance analysis of large intelligent surfaces liss uplink spectral efficiency and pilot training"):
  with members:
    - "a vision of 6g wireless systems applications trends technologies and open research problems"
    - "reliability analysis of large intelligent surfaces liss rate distribution and outage probability"
    - "towards smart and reconfigurable environment intelligent reflecting surface aided wireless network"
    - "beyond 5g with uavs foundations of a 3d wireless cellular network"
    - "energy efficient multi user miso communication using low resolution large intelligent surfaces"
    - "joint communication and control for wireless autonomous vehicular platoon systems"
    - "beyond massive mimo the potential of positioning with large intelligent surfaces"
    - "capacity degradation with modeling hardware impairment in large intelligent surface"

Connected through hyperedge HE-5 (induced by source paper "reconfigurable intelligent surfaces for energy efficiency in wireless communication"):
  with members:
    - "energy efficient multi user miso communication using low resolution large intelligent surfaces"
    - "achievable rate maximization by passive intelligent mirrors"
    - "using any surface to realize a new paradigm for wireless communications"
    - "energy efficiency of mmwave massive mimo precoding with low resolution dacs"
    - "intelligent reflecting surface enhanced wireless network via joint active and passive beamforming"
    - "deep learning coordinated beamforming for highly mobile millimeter wave systems"
    - "capacity degradation with modeling hardware impairment in large intelligent surface"
    - "asymptotically optimal estimation algorithm for the sparse signal with arbitrary distributions"

Connected through hyperedge HE-6 (induced by source paper "performance analysis of large intelligence surfaces liss asymptotic data rate and channel hardening effects"):
  with members:
    - "a vision of 6g wireless systems applications trends technologies and open research problems"
    - "energy efficient multi user miso communication using low resolution large intelligent surfaces"
    - "joint communication and control for wireless autonomous vehicular platoon systems"
    - "beyond massive mimo the potential of positioning with large intelligent surfaces"
    - "capacity degradation with modeling hardware impairment in large intelligent surface"
    - "beyond massive mimo the potential of data transmission with large intelligent surfaces"
    - "reconfigurable intelligent surfaces for energy efficiency in wireless communication"
    - "common codebook millimeter wave beam design designing beams for both sounding and communication with uniform planar arrays"

Connected through hyperedge HE-7 (induced by source paper "capacity degradation with modeling hardware impairment in large intelligent surface"):
  with members:
    - "beyond massive mimo the potential of positioning with large intelligent surfaces"
    - "beyond massive mimo the potential of data transmission with large intelligent surfaces"
    - "reciprocity calibration for massive mimo proposal modeling and validation"
    - "massive mimo systems with non ideal hardware energy efficiency estimation and capacity limits"
    - "massive mimo for next generation wireless systems"
    - "what will 5g be"
    - "scaling up mimo opportunities and challenges with very large arrays"
    - "mimo transmission with residual transmit rf impairments"

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)