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: "ambient backscatter communications a contemporary survey"
  Abstract: Recently, ambient backscatter communications has been introduced as a cutting-edge technology which enables smart devices to communicate by utilizing ambient radio frequency (RF) signals without requiring active RF transmission. This technology is especially effective in addressing communication and energy efficiency problems for low-power communications systems such as sensor networks. It is expected to realize numerous Internet-of-Things (IoT) applications. Therefore, this paper aims to provide a contemporary and comprehensive literature review on fundamentals, applications, challenges, and research efforts/progress of ambient backscatter communications. In particular, we first present fundamentals of backscatter communications and briefly review bistatic backscatter communications systems. Then, the general architecture, advantages, and solutions to address existing issues and limitations of ambient backscatter communications systems are discussed. Additionally, emerging applications of ambient backscatter communications are highlighted. Finally, we outline some open issues and future research directions.

Connected through hyperedge HE-1 (induced by source paper "irs based wireless jamming attacks when jammers can attack without power"):
  with members:
    - "secure wireless communication via intelligent reflecting surface"
    - "enabling secure wireless communications via intelligent reflecting surfaces"
    - "towards smart radio environment for wireless communications via intelligent reflecting surfaces a comprehensive survey"
    - "intelligent reflecting surface enhanced wireless network via joint active and passive beamforming"
    - "reconfigurable intelligent surfaces for energy efficiency in wireless communication"

Connected through hyperedge HE-2 (induced by source paper "capitalizing backscatter aided hybrid relay communications with wireless energy harvesting"):
  with members:
    - "cooperative ambient backscatter communications for green internet of things"
    - "optimal time scheduling for wireless powered backscatter communication networks"
    - "practical non linear energy harvesting model and resource allocation for swipt systems"
    - "relaying protocols for wireless energy harvesting and information processing"
    - "network beamforming using relays with perfect channel information"

Connected through hyperedge HE-3 (induced by source paper "mobility assisted over the air computation for backscatter sensor networks"):
  with members:
    - "uav data collection over noma backscatter networks uav altitude and trajectory optimization"
    - "joint altitude beamwidth location and bandwidth optimization for uav enabled communications"
    - "reduced dimension design of mimo over the air computing for data aggregation in clustered iot networks"

Connected through hyperedge HE-4 (induced by source paper "from a human centric perspective what might 6g be"):
  with members:
    - "towards 6g networks use cases and technologies"
    - "capacity and coverage enhancement using long endurance tethered airborne base stations"
    - "enabling smart buildings by indoor visible light communications and machine learning"
    - "a key 6g challenge and opportunity connecting the remaining 4 billions a survey on rural connectivity"
    - "6g the next frontier"
    - "evolution of physical layer communications research in the post 5g era"
    - "ultrareliable and low latency communication techniques for tactile internet services"
    - "a vision of 6g wireless systems applications trends technologies and open research problems"

Connected through hyperedge HE-5 (induced by source paper "design of ambient backscatter training for retrodirective wireless power transfer"):
  with members:
    - "retrodirective large antenna energy beamforming in backscatter multi user networks"
    - "retrodirective multi user wireless power transfer with massive mimo"
    - "next generation backscatter communication systems techniques and applications"
    - "modulation in the air backscatter communication over ambient ofdm carrier"
    - "inter technology backscatter towards internet connectivity for implanted devices"
    - "communications and signals design for wireless power transmission"
    - "wireless powered communication opportunities and challenges"
    - "performance analysis of massive mimo for cell boundary users"

Connected through hyperedge HE-6 (induced by source paper "uav data collection over noma backscatter networks uav altitude and trajectory optimization"):
  with members:
    - "3 d placement of an unmanned aerial vehicle base station for maximum coverage of users with different qos requirements"
    - "ultra reliable uav communication using altitude and cooperation diversity"
    - "efficient 3d placement of a uav using particle swarm optimization"
    - "lora backscatter enabling the vision of ubiquitous connectivity"
    - "backscatter communications for internet of things theory and applications"
    - "joint trajectory and communication design for multi uav enabled wireless networks"
    - "power domain non orthogonal multiple access noma in 5g systems potentials and challenges"
    - "a survey on non orthogonal multiple access for 5g networks research challenges and future trends"

Connected through hyperedge HE-7 (induced by source paper "reusing wireless power transfer for backscatter assisted relaying in wpcns"):
  with members:
    - "backscatter assisted relaying in wireless powered communications network"
    - "deep reinforcement learning for online computation offloading in wireless powered mobile edge computing networks"
    - "joint tx power allocation and rx power splitting for swipt system with multiple nonlinear energy harvesting circuits"
    - "multi antenna enabled cluster based cooperation in wireless powered communication networks"
    - "distributed scheduling in wireless powered communication network protocol design and performance analysis"
    - "user cooperation for enhanced throughput fairness in wireless powered communication networks"
    - "distributed charging control in broadband wireless power transfer networks"
    - "wirelessly powered backscatter communication networks modeling coverage and capacity"

Connected through hyperedge HE-8 (induced by source paper "large intelligent surface antennas lisa making reflective radios smart"):
  with members:
    - "miso wireless communication systems via intelligent reflecting surfaces"
    - "enabling large intelligent surfaces with compressive sensing and deep learning"
    - "cooperative ambient backscatter communications for green internet of things"
    - "achievable rate maximization by passive intelligent mirrors"
    - "intelligent reflecting surface enhanced wireless network via joint active and passive beamforming"
    - "symbiotic radio a new communication paradigm for passive internet of things"
    - "riding on the primary a new spectrum sharing paradigm for wireless powered iot devices"
    - "beamforming optimization for intelligent reflecting surface with discrete phase shifts"

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.NI(Networking and Internet Architecture)