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: "application of smart antenna technologies in simultaneous wireless information and power transfer"
  Abstract: Simultaneous wireless information and power transfer (SWIPT) is a promising solution to increase the lifetime of wireless nodes and hence alleviate the energy bottleneck of energy constrained wireless networks. As an alternative to conventional energy harvesting techniques, SWIPT relies on the use of radio frequency signals, and is expected to bring some fundamental changes to the design of wireless communication networks. This article focuses on the application of advanced smart antenna technologies, including multiple-input multiple-output and relaying techniques, to SWIPT. These smart antenna technologies have the potential to significantly improve the energy efficiency and also the spectral efficiency of SWIPT. Different network topologies with single and multiple users are investigated, along with some promising solutions to achieve a favorable trade-off between system performance and complexity. A detailed discussion of future research challenges for the design of SWIPT systems is also provided.

Connected through hyperedge HE-1 (induced by source paper "simultaneous wireless information and power transfer for decode and forward multihop relay systems in energy constrained iot networks"):
  with members:
    - "end to end throughput maximization for underlay multi hop cognitive radio networks with rf energy harvesting"
    - "retrodirective multi user wireless power transfer with massive mimo"
    - "simultaneous information and energy flow for iot relay systems with crowd harvesting"
    - "wireless powered communication opportunities and challenges"
    - "resource allocation techniques for wireless powered communication networks with energy storage constraint"
    - "energy harvesting wireless communications a review of recent advances"
    - "wireless networks with rf energy harvesting a contemporary survey"
    - "wireless information and power transfer a dynamic power splitting approach"

Connected through hyperedge HE-2 (induced by source paper "conditional capacity and transmit signal design for swipt systems with multiple nonlinear energy harvesting receivers"):
  with members:
    - "fundamentals of wireless information and power transfer from rf energy harvester models to signal and system designs"
    - "on the capacity of swipt systems with a nonlinear energy harvesting circuit"
    - "on capacity achieving distributions over complex awgn channels under nonlinear power constraints and their applications to swipt"
    - "wireless information and power transfer over an awgn channel nonlinearity and asymmetric gaussian signaling"
    - "waveform optimization for radio frequency wireless power transfer"
    - "waveform design for wireless power transfer"
    - "wireless information and power transfer nonlinearity waveform design and rate energy tradeoff"
    - "practical non linear energy harvesting model and resource allocation for swipt systems"

Connected through hyperedge HE-3 (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"
    - "some new research trends in wirelessly powered communications"
    - "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"
    - "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-4 (induced by source paper "mimo underlay cognitive radio optimized power allocation effective number of transmit antennas and harvest transmit tradeoff"):
  with members:
    - "rf based energy harvesting in decode and forward relaying systems ergodic and outage capacities"
    - "jointly optimal spatial channel assignment and power allocation for mimo swipt systems"
    - "optimal power allocation and active interference mitigation for spatial multiplexed mimo cognitive systems"
    - "simultaneous spectrum sensing and data reception for cognitive spatial multiplexing distributed systems"
    - "full duplex mimo small cell networks with interference cancellation"
    - "practical non linear energy harvesting model and resource allocation for swipt systems"
    - "energy efficiency in massive mimo based 5g networks opportunities and challenges"
    - "full duplex wireless powered relay with self energy recycling"

Connected through hyperedge HE-5 (induced by source paper "hybrid precoding based millimeter wave massive mimo noma with simultaneous wireless information and power transfer"):
  with members:
    - "machine learning inspired energy efficient hybrid precoding for mmwave massive mimo systems"
    - "secure swipt networks based on a non linear energy harvesting model"
    - "energy efficient power allocation in millimeter wave massive mimo with non orthogonal multiple access"
    - "joint beamforming and power splitting control in downlink cooperative swipt noma systems"
    - "an overview of signal processing techniques for millimeter wave mimo systems"
    - "limited feedback hybrid precoding for multi user millimeter wave systems"
    - "a general mimo framework for noma downlink and uplink transmission based on signal alignment"
    - "simultaneous wireless information and power transfer in modern communication systems"

Connected through hyperedge HE-6 (induced by source paper "optimization vs reinforcement learning for wirelessly powered sensor networks"):
  with members:
    - "waveform design for wireless power transfer with limited feedback"
    - "wireless power transfer for distributed estimation in sensor networks"
    - "robust resource allocation for mimo wireless powered communication networks based on a non linear eh model"
    - "waveform design for wireless power transfer"
    - "wireless information and power transfer nonlinearity waveform design and rate energy tradeoff"
    - "benchmarking deep reinforcement learning for continuous control"
    - "practical non linear energy harvesting model and resource allocation for swipt systems"
    - "trust region policy optimization"

Connected through hyperedge HE-7 (induced by source paper "wireless powered dual hop multi antenna relaying systems impact of csi and antenna correlation"):
  with members:
    - "on the performance of multi antenna wireless powered communications with energy beamforming"
    - "an overview of sustainable green 5g networks"
    - "training based swipt optimal power splitting at the receiver"
    - "joint wireless information and power transfer for an autonomous multiple antenna relay system"
    - "wireless powered communications performance analysis and optimization"
    - "energy efficient resource allocation for wireless powered communication networks"
    - "wireless information and power transfer in relay systems with multiple antennas and interference"
    - "harvest then cooperate wireless powered cooperative communications"

Connected through hyperedge HE-8 (induced by source paper "optimization and analysis of wireless powered multi antenna cooperative systems"):
  with members:
    - "on the performance of multi antenna wireless powered communications with energy beamforming"
    - "relaying strategies for wireless powered mimo relay networks"
    - "wireless powered communication opportunities and challenges"
    - "on the efficiency of far field wireless power transfer"
    - "wireless powered communications performance analysis and optimization"
    - "energy efficient resource allocation for wireless powered communication networks"
    - "optimum wirelessly powered relaying"
    - "spatial throughput maximization of wireless powered communication networks"

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)