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: "semi coherent detection and performance analysis for ambient backscatter system"
  Abstract: We study a novel communication mechanism, ambient backscatter, that utilizes radio frequency (RF) signals transmitted from an ambient source as both energy supply and information carrier to enable communications between low-power devices. Different from existing non-coherent schemes, we here design the semi-coherent detection, where channel parameters can be obtained from unknown data symbols and a few pilot symbols. We first derive the optimal detector for the complex Gaussian ambient RF signal from likelihood ratio test and compute the corresponding closed-form bit error rate (BER). To release the requirement for prior knowledge of the ambient RF signal, we next design a suboptimal energy detector with ambient RF signals being either the complex Gaussian or the phase shift keying (PSK). The corresponding detection thresholds, the analytical BER, and the outage probability are also obtained in closed-form. Interestingly, the complex Gaussian source would cause an error floor while the PSK source does not, which brings nontrivial indication of constellation design as opposed to the popular Gaussian-embedded literatures. Simulations are provided to corroborate the theoretical studies.

Connected through hyperedge HE-1 (induced by source paper "non coherent detection and bit error rate for an ambient backscatter link in time selective fading"):
  with members:
    - "ambient backscatter systems exact average bit error rate under fading channels"
    - "modulation in the air backscatter communication over ambient ofdm carrier"
    - "wide area wireless communication challenges for the internet of things"
    - "wireless backhaul networks capacity bound scalability analysis and design guidelines"
    - "massive mimo meets hetnet interference coordination through spatial blanking"
    - "joint spatial division and multiplexing for mm wave channels"

Connected through hyperedge HE-2 (induced by source paper "performance characterisation of relaying using backscatter devices"):
  with members:
    - "ambient backscatter systems exact average bit error rate under fading channels"
    - "fm backscatter enabling connected cities and smart fabrics"
    - "modulation in the air backscatter communication over ambient ofdm carrier"
    - "backscatter communications for the internet of things a stochastic geometry approach"
    - "wirelessly powered backscatter communication networks modeling coverage and capacity"

Connected through hyperedge HE-3 (induced by source paper "optimal channel estimation for reciprocity based backscattering with a full duplex mimo reader"):
  with members:
    - "lora backscatter enabling the vision of ubiquitous connectivity"
    - "modulation in the air backscatter communication over ambient ofdm carrier"
    - "communications and signals design for wireless power transmission"
    - "multi antenna wireless energy transfer for backscatter communication systems"

Connected through hyperedge HE-4 (induced by source paper "matched filter based backscatter communication for iot devices over ambient ofdm carrier"):
  with members:
    - "cooperative ambient backscatter communications for green internet of things"
    - "optimal resource allocation in full duplex ambient backscatter communication networks for wireless powered iot"
    - "modulation in the air backscatter communication over ambient ofdm carrier"

Connected through hyperedge HE-5 (induced by source paper "optimal non coherent detector for ambient backscatter communication system"):
  with members:
    - "next generation backscatter communication systems techniques and applications"
    - "ambient backscatter communications a contemporary survey"
    - "modulation in the air backscatter communication over ambient ofdm carrier"

Connected through hyperedge HE-6 (induced by source paper "ambient backscatter systems exact average bit error rate under fading channels"):
  with members:
    - "lora backscatter enabling the vision of ubiquitous connectivity"
    - "modulation in the air backscatter communication over ambient ofdm carrier"
    - "inter technology backscatter towards internet connectivity for implanted devices"
    - "wirelessly powered backscatter communication networks modeling coverage and capacity"

Connected through hyperedge HE-7 (induced by source paper "ambient backscatter communications a contemporary survey"):
  with members:
    - "cooperative ambient backscatter communications for green internet of things"
    - "pixelated vlc backscattering for self charging indoor iot devices"
    - "wirelessly powered backscatter communications waveform design and snr energy tradeoff"
    - "lora backscatter enabling the vision of ubiquitous connectivity"
    - "backscatter communications for internet of things theory and applications"
    - "ambient backscatter networking a novel paradigm to assist wireless powered communications"
    - "backscatter multiplicative multiple access systems fundamental limits and practical design"
    - "scatter radio receivers for extended range environmental sensing wsns"

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)