human: Given a hyperedge-centered hypergraph: <hypergraph>, where the center hyperedge is induced by one source paper and its member nodes are the cited papers.

Details of the hypergraph:
Center hyperedge (induced by source paper "design of ambient backscatter training for retrodirective wireless power transfer"):
  Abstract: Wireless power transfer (WPT) using energy beamforming is a promising solution for low power devices in the future Internet of Things (IoT). In this work, we propose a WPT scenario with a retrodirective antenna at the energy transmitter (ET) and ambient backscatter at the energy receiver (ER). The retrodirective WPT at the ET eliminates the requirement of knowing the channel from the ET to ER, and the use of ambient backscattering (as opposed to active transmission) minimizes the energy consumption at the ER. We propose a training sequence design, i.e., the pattern of varying the reflection coefficient at the ER, to eliminate the direct-link interference from the ambient source. We show that when the ambient symbol duration is known, the ambient interference is fully cancelled by using the proposed design. We analytically model the system and derive a closed-form expression for the average harvested power at the ER, assuming that the retrodirective array size is large. Our results show that with practical parameter values, the proposed solution is robust to a small timing offset mismatch at the correlator and allows the ER to successfully harvest tens of $\mu$W of power, which is an important improvement for low-power IoT devices.

Includes members:
  Member "retrodirective large antenna energy beamforming in backscatter multi user networks":
    also connected through other hyperedges:
      - Hyperedge HE-1 (induced by source paper "a retrodirective wireless power transfer scheme for ambient backscatter systems")
  Member "retrodirective multi user wireless power transfer with massive mimo":
    also connected through other hyperedges:
      - Hyperedge HE-2 (induced by source paper "a retrodirective wireless power transfer scheme for ambient backscatter systems")
  Member "next generation backscatter communication systems techniques and applications":
    also connected through other hyperedges:
      - Hyperedge HE-3 (induced by source paper "on the performance of splitting receiver with joint coherent and non coherent processing")
  Member "ambient backscatter communications a contemporary survey":
    also connected through other hyperedges:
      - Hyperedge HE-4 (induced by source paper "irs based wireless jamming attacks when jammers can attack without power")
  Member "modulation in the air backscatter communication over ambient ofdm carrier":
    also connected through other hyperedges:
      - Hyperedge HE-5 (induced by source paper "a retrodirective wireless power transfer scheme for ambient backscatter systems")
  Member "inter technology backscatter towards internet connectivity for implanted devices":
    also connected through other hyperedges:
      - Hyperedge HE-6 (induced by source paper "tunnelscatter low power communication for sensor tags using tunnel diodes")
  Member "communications and signals design for wireless power transmission":
    also connected through other hyperedges:
      - Hyperedge HE-7 (induced by source paper "wirelessly powered sensor networks power allocation for channel estimation and energy beamforming")
  Member "wireless powered communication opportunities and challenges":
    also connected through other hyperedges:
      - Hyperedge HE-8 (induced by source paper "wirelessly powered sensor networks power allocation for channel estimation and energy beamforming")

Question: Please tell me which class the source paper 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)