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: "unitary query for the m times l times n mimo backscatter rfid channel"
  Abstract: A MIMO backscatter RFID system consists of three operational ends: the query end (with $M$ reader transmitting antennas), the tag end (with $L$ tag antennas) and the receiving end (with $N$ reader receiving antennas). Such an $M \times L \times N$ setting in RFID can bring spatial diversity and has been studied for STC at the tag end. Current understanding of the query end is that it is only an energy provider for the tag and query signal designs cannot improve the performance. However, we propose a novel \textit{unitary query} scheme, which creates time diversity \emph{within channel coherent time} and can yield \emph{significant} performance improvements. To overcome the difficulty of evaluating the performance when the unitary query is employed at the query end and STC is employed at the tag end, we derive a new measure based on the ranks of certain carefully constructed matrices. The measure implies that the unitary query has superior performance. Simulations show that the unitary query can bring $5-10$ dB gain in mid SNR regimes. In addition, the unitary query can also improve the performance of single-antenna tags significantly, allowing employing low complex and small-size single-antenna tags for high performance. This improvement is unachievable for single-antenna tags when the conventional uniform query is employed.

Connected through hyperedge HE-1 (induced by source paper "wireless powered asynchronous backscatter networks with sporadic short packets performance analysis and optimization"):
  with members:
    - "modeling and analysis of cellular networks using stochastic geometry a tutorial"
    - "backscatter communications for the internet of things a stochastic geometry approach"
    - "physical layer security in mimo backscatter wireless systems"
    - "full duplex backscatter interference networks based on time hopping spread spectrum"
    - "some new research trends in wirelessly powered communications"
    - "massive machine type communications in 5g physical and mac layer solutions"
    - "wirelessly powered backscatter communication networks modeling coverage and capacity"
    - "wireless powered communication opportunities and challenges"

Connected through hyperedge HE-2 (induced by source paper "physical layer security in mimo backscatter wireless systems"):
  with members:
    - "joint beamforming optimization and power control for full duplex mimo two way relay channel"
    - "principles of physical layer security in multiuser wireless networks a survey"
    - "spatially selective artificial noise aided transmit optimization for miso multi eves secrecy rate maximization"
    - "on cooperative relaying schemes for wireless physical layer security"
    - "the secrecy capacity of the mimo wiretap channel"

Connected through hyperedge HE-3 (induced by source paper "multi antenna wireless energy transfer for backscatter communication systems"):
  with members:
    - "throughput optimization for massive mimo systems powered by wireless energy transfer"
    - "energy beamforming with one bit feedback"
    - "optimized training design for wireless energy transfer"
    - "dynamic resource allocation for multiple antenna wireless power transfer"
    - "mimo broadcasting for simultaneous wireless information and power transfer"

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)