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: "on the capacity of free space optical intensity channels"
  Abstract: New upper and lower bounds are presented on the capacity of the free-space optical intensity channel. This channel is characterized by inputs that are nonnegative (representing the transmitted optical intensity) and by outputs that are corrupted by additive white Gaussian noise (because in free space the disturbances arise from many independent sources). Due to battery and safety reasons the inputs are simultaneously constrained in both their average and peak power. For a fixed ratio of the average power to the peak power the difference between the upper and the lower bounds tends to zero as the average power tends to infinity, and the ratio of the upper and lower bounds tends to one as the average power tends to zero. The case where only an average-power constraint is imposed on the input is treated separately. In this case, the difference of the upper and lower bound tends to 0 as the average power tends to infinity, and their ratio tends to a constant as the power tends to zero.

Connected through hyperedge HE-1 (induced by source paper "throughput maximization of mixed fso rf uav aided mobile relaying with a buffer"):
  with members:
    - "a qos oriented trajectory optimization in swarming unmanned aerial vehicles communications"
    - "a uav mounted free space optical communication trajectory optimization for flight time"
    - "energy minimization for wireless communication with rotary wing uav"
    - "a tutorial on uavs for wireless networks applications challenges and open problems"
    - "survey of important issues in uav communication networks"
    - "energy efficient uav communication with trajectory optimization"
    - "fso based vertical backhaul fronthaul framework for 5g wireless networks"
    - "wireless communications with unmanned aerial vehicles opportunities and challenges"

Connected through hyperedge HE-2 (induced by source paper "ultra small cell networks with collaborative rf and lightwave power transfer"):
  with members:
    - "robust design of ac computing enabled receiver architecture for swipt networks"
    - "fundamentals of wireless information and power transfer from rf energy harvester models to signal and system designs"
    - "green cell less design for rf wireless power transfer networks"
    - "rf wireless power transfer regreening future networks"
    - "coverage and rate analysis for co existing rf vlc downlink cellular networks"
    - "robust resource allocation for mimo wireless powered communication networks based on a non linear eh model"
    - "waveform design for wireless power transfer"
    - "practical non linear energy harvesting model and resource allocation for swipt systems"

Connected through hyperedge HE-3 (induced by source paper "a uav mounted free space optical communication trajectory optimization for flight time"):
  with members:
    - "uav aided offloading for cellular hotspot"
    - "an edge computing empowered radio access network with uav mounted fso fronthaul and backhaul key challenges and approaches"
    - "optimizing communication and computation for multi uav information gathering applications"
    - "wireless communication using unmanned aerial vehicles uavs optimal transport theory for hover time optimization"
    - "joint trajectory and communication design for multi uav enabled wireless networks"
    - "mobile unmanned aerial vehicles uavs for energy efficient internet of things communications"
    - "energy efficient uav communication with trajectory optimization"
    - "designing and implementing future aerial communication networks"

Connected through hyperedge HE-4 (induced by source paper "on the performance of splitting receiver with joint coherent and non coherent processing"):
  with members:
    - "signal processing for high throughput satellites challenges in new interference limited scenarios"
    - "fundamentals of wireless information and power transfer from rf energy harvester models to signal and system designs"
    - "a novel receiver design with joint coherent and non coherent processing"
    - "channel estimation and performance analysis of one bit massive mimo systems"
    - "next generation backscatter communication systems techniques and applications"
    - "dense small cell networks from noise limited to dense interference limited"
    - "design and performance analysis of noncoherent detection systems with massive receiver arrays"
    - "capacity analysis of one bit quantized mimo systems with transmitter channel state information"

Connected through hyperedge HE-5 (induced by source paper "noma for vlc downlink transmission with random receiver orientation"):
  with members:
    - "angle feedback for noma transmission in mmwave drone networks"
    - "modeling the random orientation of mobile devices measurement analysis and lifi use case"
    - "a software defined multi element vlc architecture"
    - "multi element vlc networks led assignment power control and optimum combining"
    - "power domain non orthogonal multiple access noma in 5g systems potentials and challenges"
    - "impact of random receiver orientation on visible light communications channel"
    - "non orthogonal multiple access for visible light communications"
    - "non orthogonal multiple access in multi cell networks theory performance and practical challenges"

Connected through hyperedge HE-6 (induced by source paper "shadowed fso mmwave systems with interference"):
  with members:
    - "performance of a free space optical relay assisted hybrid rf fso system in generalized m distributed channels"
    - "mimo channel modeling and capacity analysis for 5g millimeter wave wireless systems"
    - "5g ultra dense cellular networks"
    - "on the ergodic capacity of underlay cognitive dual hop af relayed systems under non identical generalized k fading channels"
    - "unified performance analysis of mixed radio frequency free space optical dual hop transmission systems"
    - "coverage and rate analysis for millimeter wave cellular networks"
    - "millimeter wave channel modeling and cellular capacity evaluation"

Connected through hyperedge HE-7 (induced by source paper "on the secrecy rate of spatial modulation based indoor visible light communications"):
  with members:
    - "adaptive spatial modulation for visible light communications with an arbitrary number of transmitters"
    - "adaptive spatial modulation based visible light communications ser analysis and optimization"
    - "physical layer security for indoor visible light communications secrecy capacity analysis"
    - "what will 5g be"
    - "generalised sphere decoding for spatial modulation"

Connected through hyperedge HE-8 (induced by source paper "on the capacity of mimo optical wireless channels"):
  with members:
    - "capacity results on multiple input single output wireless optical channels"
    - "upper and lower bounds on the capacity of amplitude constrained mimo channels"
    - "capacity bounds for discrete time amplitude constrained additive white gaussian noise channels"

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)