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: "some new research trends in wirelessly powered communications"
  Abstract: The vision of seamlessly integrating information transfer (IT) and microwave-based power transfer (PT) in the same system has led to the emergence of a new research area, called wirelessly powered communications (WPC). Extensive research has been conducted on developing WPC theory and techniques, building on the extremely rich wireless communications literature covering diversified topics such as transmission, resource allocation, medium access control, and network protocols and architectures. Despite these research efforts, transforming WPC from theory to practice still faces many unsolved problems concerning issues such as mobile complexity, power transfer efficiency, and safety. Furthermore, the fundamental limits of WPC remain largely unknown. Recent attempts to address these open issues have resulted in the emergence of numerous new research trends in the WPC area. A few promising trends are introduced in this article. From the practical perspective, the use of backscatter antennas can support WPC for low-complexity passive devices, the design of spiky waveforms can improve the PT efficiency, and analog spatial decoupling is proposed for solving the PT-IT near-far problem in WPC. From the theoretic perspective, the fundamental limit of WPC can be quantified by leveraging recent results on super-directivity, and the limit can be improved by the deployment of large-scale distributed antenna arrays. Specific research problems along these trends are discussed, the solutions of which can lead to significant advancements in WPC.

Connected through hyperedge HE-1 (induced by source paper "transmission delay minimization in wireless powered communication systems"):
  with members:
    - "power allocation and effective capacity of af successive relays"
    - "optimization and analysis of wireless powered multi antenna cooperative systems"
    - "cross layer optimization for ultra reliable and low latency radio access networks"
    - "wireless powered dual hop multi antenna relaying systems impact of csi and antenna correlation"
    - "effective capacity of receive antenna selection mimo ostbc systems in co channel interference"
    - "wireless charging technologies fundamentals standards and network applications"
    - "wireless powered communication networks an overview"
    - "wireless powered communication opportunities and challenges"

Connected through hyperedge HE-2 (induced by source paper "robust designs of beamforming and power splitting for distributed antenna systems with wireless energy harvesting"):
  with members:
    - "beamforming and power splitting designs for an aided secure multi user mimo swipt systems"
    - "robust beamforming for secure communication in systems with wireless information and power transfer"
    - "secure and green swipt in distributed antenna networks with limited backhaul capacity"
    - "joint transmit beamforming and receive power splitting for miso swipt systems"
    - "application of smart antenna technologies in simultaneous wireless information and power transfer"
    - "transmission schemes based on sum rate analysis in distributed antenna systems"
    - "mimo broadcasting for simultaneous wireless information and power transfer"
    - "outage constrained robust transmit optimization for multiuser miso downlinks tractable approximations by conic optimization"

Connected through hyperedge HE-3 (induced by source paper "wireless powered asynchronous backscatter networks with sporadic short packets performance analysis and optimization"):
  with members:
    - "modeling and analysis of cellular networks using stochastic geometry a tutorial"
    - "backscatter communications for the internet of things a stochastic geometry approach"
    - "physical layer security in mimo backscatter wireless systems"
    - "full duplex backscatter interference networks based on time hopping spread spectrum"
    - "massive machine type communications in 5g physical and mac layer solutions"
    - "wirelessly powered backscatter communication networks modeling coverage and capacity"
    - "wireless powered communication opportunities and challenges"
    - "a stochastic geometry framework for asynchronous full duplex networks"

Connected through hyperedge HE-4 (induced by source paper "retrodirective large antenna energy beamforming in backscatter multi user networks"):
  with members:
    - "retrodirective multi user wireless power transfer with massive mimo"
    - "communications and signals design for wireless power transmission"
    - "performance analysis of massive mimo for cell boundary users"
    - "on the efficiency of far field wireless power transfer"
    - "multi antenna wireless energy transfer for backscatter communication systems"
    - "energy beamforming with one bit feedback"
    - "optimized training design for wireless energy transfer"
    - "mimo broadcasting for simultaneous wireless information and power transfer"

Connected through hyperedge HE-5 (induced by source paper "distributed wireless power transfer with energy feedback"):
  with members:
    - "a general design framework for mimo wireless energy transfer with limited feedback"
    - "wireless powered communication networks an overview"
    - "wireless powered communication opportunities and challenges"
    - "distributed energy beamforming with one bit feedback"
    - "collaborative wireless energy and information transfer in interference channel"
    - "optimized training for net energy maximization in multi antenna wireless energy transfer over frequency selective channel"
    - "simultaneous wireless information and power transfer in modern communication systems"
    - "energy beamforming with one bit feedback"

Connected through hyperedge HE-6 (induced by source paper "throughput maximization for wireless powered communications harvesting from non dedicated sources"):
  with members:
    - "spatial throughput maximization of wireless powered communication networks"
    - "energy harvesting two hop communication networks"
    - "outage probability of energy harvesting relay aided cooperative networks over rayleigh fading channel"
    - "throughput maximization in wireless powered communication networks"
    - "a general framework for the optimization of energy harvesting communication systems with battery imperfections"

Connected through hyperedge HE-7 (induced by source paper "wireless information and power transfer nonlinearity waveform design and rate energy tradeoff"):
  with members:
    - "waveform design for wireless power transfer with limited feedback"
    - "wirelessly powered backscatter communications waveform design and snr energy tradeoff"
    - "large scale multiantenna multisine wireless power transfer"
    - "wireless information and power transfer over an awgn channel nonlinearity and asymmetric gaussian signaling"
    - "prototyping and experimentation of a closed loop wireless power transmission with channel acquisition and waveform optimization"
    - "low complexity adaptive multisine waveform design for wireless power transfer"
    - "waveform optimization for radio frequency wireless power transfer"
    - "waveform design for wireless power transfer"

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)