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 powered relays in cooperative communications time switching relaying protocols and throughput analysis"
  Abstract: We consider wireless-powered amplify-and-forward and decode-and-forward relaying in cooperative communications, where an energy constrained relay node first harvests energy through the received radio-frequency signal from the source and then uses the harvested energy to forward the source information to the destination node. We propose time-switching based energy harvesting (EH) and information transmission (IT) protocols with two modes of EH at the relay. For continuous time EH, the EH time can be any percentage of the total transmission block time. For discrete time EH, the whole transmission block is either used for EH or IT. The proposed protocols are attractive because they do not require channel state information at the transmitter side and enable relay transmission with preset fixed transmission power. We derive analytical expressions of the achievable throughput for the proposed protocols. The derived expressions are verified by comparison with simulations and allow the system performance to be determined as a function of the system parameters. Finally, we show that the proposed protocols outperform the existing fixed time duration EH protocols in the literature, since they intelligently track the level of the harvested energy to switch between EH and IT in an online fashion, allowing efficient use of resources.

Connected through hyperedge HE-1 (induced by source paper "on maximizing information reliability in wireless powered cooperative networks"):
  with members:
    - "sensitive and nonlinear far field rf energy harvesting in wireless communications"
    - "ergodic capacity analysis of wireless powered af relaying systems over alpha µ fading channels"
    - "joint relay selection and power allocation in large scale mimo systems with untrusted relays and passive eavesdroppers"
    - "error performance of wireless powered cognitive relay networks with interference alignment"
    - "minimizing outage probability by exploiting csi in wireless powered cooperative networks"
    - "practical non linear energy harvesting model and resource allocation for swipt systems"
    - "wireless information and power transfer in relay systems with multiple antennas and interference"
    - "power allocation strategies in energy harvesting wireless cooperative networks"

Connected through hyperedge HE-2 (induced by source paper "energy efficiency fairness for multi pair wireless powered relaying systems"):
  with members:
    - "joint power allocation and beamforming for energy efficient two way multi relay communications"
    - "energy efficiency maximization of full duplex two way relay with non ideal power amplifiers and non negligible circuit power"
    - "energy efficient beam coordination strategies with rate dependent processing power"
    - "relaying strategies for wireless powered mimo relay networks"
    - "practical non linear energy harvesting model and resource allocation for swipt systems"
    - "wireless networks with rf energy harvesting a contemporary survey"
    - "energy efficiency optimization in relay assisted mimo systems with perfect and statistical csi"
    - "power allocation strategies in energy harvesting wireless cooperative networks"

Connected through hyperedge HE-3 (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"
    - "harvest then cooperate wireless powered cooperative communications"
    - "wireless powered cooperative communications via a hybrid relay"

Connected through hyperedge HE-4 (induced by source paper "swipt using hybrid arq over time varying channels"):
  with members:
    - "channel sensing and communication over a time correlated channel with an energy harvesting transmitter"
    - "energy management for energy harvesting wireless sensors with adaptive retransmission"
    - "on distributed power control for uncoordinated dual energy harvesting links performance bounds and near optimal policies"
    - "on optimal policies in full duplex wireless powered communication networks"
    - "arq with adaptive feedback for energy harvesting receivers"
    - "communications and signals design for wireless power transmission"
    - "optimal policies for wireless networks with energy harvesting transmitters and receivers effects of decoding costs"
    - "powering the next billion devices with wi fi"

Connected through hyperedge HE-5 (induced by source paper "ultra reliable cooperative short packet communications with wireless energy transfer"):
  with members:
    - "ultra reliable short message cooperative relaying protocols under nakagami m fading"
    - "wireless powered communications with finite battery and finite blocklength"
    - "wireless powered relaying with finite block length codes"
    - "analysis of wireless communications with finite blocklength and imperfect channel knowledge"
    - "on wirelessly powered communications with short packets"
    - "harvest then cooperate wireless powered cooperative communications"
    - "wireless networks with rf energy harvesting a contemporary survey"
    - "finite block length analysis of the incremental redundancy harq"

Connected through hyperedge HE-6 (induced by source paper "optimization of a power splitting protocol for two way multiple energy harvesting relay system"):
  with members:
    - "rf based energy harvesting in decode and forward relaying systems ergodic and outage capacities"
    - "throughput maximization for two way relay channels with energy harvesting nodes the impact of relaying strategies"
    - "energy harvesting wireless communications a review of recent advances"
    - "secure communication via a wireless energy harvesting untrusted relay"
    - "outage analysis of cooperative transmission with energy harvesting relay time switching vs power splitting"
    - "joint resource optimization for multicell networks with wireless energy harvesting relays"
    - "wireless networks with rf energy harvesting a contemporary survey"
    - "relaying protocols for wireless energy harvesting and information processing"

Connected through hyperedge HE-7 (induced by source paper "interference aided energy harvesting cognitive relaying with multiple primary transceivers"):
  with members:
    - "rf based energy harvesting in decode and forward relaying systems ergodic and outage capacities"
    - "wireless energy harvesting in a cognitive relay network"
    - "optimal time sharing in underlay cognitive radio systems with rf energy harvesting"
    - "distributed power splitting for swipt in relay interference channels using game theory"
    - "wireless powered communications performance analysis and optimization"
    - "interference assisted wireless energy harvesting in cognitive relay network with multiple primary transceivers"
    - "outage analysis of spectrum sharing energy harvesting cognitive relays in nakagami m channels"
    - "harvest then cooperate wireless powered cooperative communications"

Connected through hyperedge HE-8 (induced by source paper "energy harvesting based secure two way communication using an untrusted relay"):
  with members:
    - "joint relay selection and power allocation in large scale mimo systems with untrusted relays and passive eavesdroppers"
    - "optimal power allocation and secrecy sum rate in two way untrusted relaying"
    - "joint relay and jammer selection improves the physical layer security in the face of csi feedback delays"
    - "secure communication via a wireless energy harvesting untrusted relay"
    - "security versus reliability analysis of opportunistic relaying"
    - "secure communication with a wireless powered friendly jammer"
    - "secure beamforming for mimo two way communications with an untrusted relay"

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)