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: "wireless information and power transfer energy efficiency optimization in ofdma systems"
  Abstract: This paper considers orthogonal frequency division multiple access (OFDMA) systems with simultaneous wireless information and power transfer. We study the resource allocation algorithm design for maximization of the energy efficiency of data transmission (bits/Joule delivered to the receivers). In particular, we focus on power splitting hybrid receivers which are able to split the received signals into two power streams for concurrent information decoding and energy harvesting. Two scenarios are investigated considering different power splitting abilities of the receivers. In the first scenario, we assume receivers which can split the received power into a continuous set of power streams with arbitrary power splitting ratios. In the second scenario, we examine receivers which can split the received power only into a discrete set of power streams with fixed power splitting ratios. For both scenarios, we formulate the corresponding algorithm design as a non-convex optimization problem which takes into account the circuit power consumption, the minimum data rate requirements of delay constrained services, the minimum required system data rate, and the minimum amount of power that has to be delivered to the receivers. By exploiting fractional programming and dual decomposition, suboptimal iterative resource allocation algorithms are developed to solve the non-convex problems. Simulation results illustrate that the proposed iterative resource allocation algorithms approach the optimal solution within a small number of iterations and unveil the trade-off between energy efficiency, system capacity, and wireless power transfer: (1) wireless power transfer enhances the system energy efficiency by harvesting energy in the radio frequency, especially in the interference limited regime; (2) the presence of multiple receivers is beneficial for the system capacity, but not necessarily for the system energy efficiency.

Connected through hyperedge HE-1 (induced by source paper "on the performance gain of noma over oma in uplink communication systems"):
  with members:
    - "a two stage beam alignment framework for hybrid mmwave distributed antenna systems"
    - "on the performance gain of noma over oma in uplink single cell systems"
    - "a distributed multi rf chain hybrid mmwave scheme for small cell systems"
    - "multi beam noma for hybrid mmwave systems"
    - "joint pilot and payload power control for uplink mimo noma with mrc sic receivers"
    - "multi cell hybrid millimeter wave systems pilot contamination and interference mitigation"
    - "noma aided narrowband iot for machine type communications with user clustering"
    - "non orthogonal multiple access common myths and critical questions"

Connected through hyperedge HE-2 (induced by source paper "energy efficiency of distributed antenna systems with wireless power transfer"):
  with members:
    - "energy efficient swipt in iot distributed antenna systems"
    - "wirelessly powered backscatter communications waveform design and snr energy tradeoff"
    - "fundamental green tradeoffs progresses challenges and impacts on 5g networks"
    - "power allocation for secure swipt systems with wireless powered cooperative jamming"
    - "wireless information and power transfer nonlinearity waveform design and rate energy tradeoff"
    - "artificial noise aided secrecy information and power transfer in ofdma systems"
    - "information and energy cooperation in ofdm relaying protocols and optimization"
    - "secure and green swipt in distributed antenna networks with limited backhaul capacity"

Connected through hyperedge HE-3 (induced by source paper "energy efficiency maximization via joint sub carrier assignment and power control for ofdma full duplex networks"):
  with members:
    - "energy efficient power control a look at 5g wireless technologies"
    - "optimal joint power and subcarrier allocation for full duplex multicarrier non orthogonal multiple access systems"
    - "energy efficient heterogeneous cellular networks with spectrum underlay and overlay access"
    - "power efficient resource allocation for full duplex radio distributed antenna networks"
    - "throughput analysis for full duplex wireless networks with imperfect self interference cancellation"
    - "power efficient and secure full duplex wireless communication systems"
    - "energy efficient scheduling and power allocation in downlink ofdma networks with base station coordination"
    - "full duplex mobile device pushing the limits"

Connected through hyperedge HE-4 (induced by source paper "energy efficient resource allocation for wirelessly powered backscatter communications"):
  with members:
    - "multiuser wirelessly powered backscatter communications nonlinearity waveform design and sinr energy tradeoff"
    - "riding on the primary a new spectrum sharing paradigm for wireless powered iot devices"
    - "wirelessly powered backscatter communications waveform design and snr energy tradeoff"
    - "wireless powered device to device communications with ambient backscattering performance modeling and analysis"
    - "ambient backscatter communications a contemporary survey"
    - "waveform design for wireless power transfer"
    - "wirelessly powered backscatter communication networks modeling coverage and capacity"
    - "communications and signals design for wireless power transmission"

Connected through hyperedge HE-5 (induced by source paper "full duplex mimo ofdm communication with self energy recycling"):
  with members:
    - "non orthogonal multiple access in large scale heterogeneous networks"
    - "ambient rf energy harvesting in ultra dense small cell networks performance and trade offs"
    - "wireless information and energy transfer for two hop non regenerative mimo ofdm relay networks"
    - "wireless networks with rf energy harvesting a contemporary survey"
    - "wireless information and power transfer in multiuser ofdm systems"
    - "relaying protocols for wireless energy harvesting and information processing"

Connected through hyperedge HE-6 (induced by source paper "charge then forward wireless powered communication for multiuser relay networks"):
  with members:
    - "joint power allocation and beamforming for energy efficient two way multi relay communications"
    - "power allocation for secure swipt systems with wireless powered cooperative jamming"
    - "capacity of the two hop relay channel with wireless energy transfer from relay to source and energy transmission cost"
    - "multipair two way relay network with harvest then transmit users resolving pairwise uplink downlink coupling"
    - "artificial noise aided secrecy information and power transfer in ofdma systems"
    - "wireless powered communication opportunities and challenges"
    - "wireless powered relays in cooperative communications time switching relaying protocols and throughput analysis"
    - "harvest then cooperate wireless powered cooperative communications"

Connected through hyperedge HE-7 (induced by source paper "energy efficient resource allocation in machine to machine communications with multiple access and energy harvesting for iot"):
  with members:
    - "on user pairing in noma uplink"
    - "distributed user association in energy harvesting small cell networks an exchange economy with uncertainty"
    - "wireless energy harvesting in a cognitive relay network"
    - "power allocation and scheduling for swipt systems with non linear energy harvesting model"
    - "wireless powered communication opportunities and challenges"
    - "downlink power control in two tier cellular networks with energy harvesting small cells as stochastic games"
    - "power and load coupling in cellular networks for energy optimization"
    - "practical non linear energy harvesting model and resource allocation for swipt systems"

Connected through hyperedge HE-8 (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"

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)