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: "tracking angles of departure and arrival in a mobile millimeter wave channel"
  Abstract: Millimeter wave provides a very promising approach for meeting the ever-growing traffic demand in next generation wireless networks. To utilize this band, it is crucial to obtain the channel state information in order to perform beamforming and combining to compensate for severe path loss. In contrast to lower frequencies, a typical millimeter wave channel consists of a few dominant paths. Thus it is generally sufficient to estimate the path gains, angles of departure (AoDs), and angles of arrival (AoAs) of those paths. Proposed in this paper is a dual timescale model to characterize abrupt channel changes (e.g., blockage) and slow variations of AoDs and AoAs. This work focuses on tracking the slow variations and detecting abrupt changes. A Kalman filter based tracking algorithm and an abrupt change detection method are proposed. The tracking algorithm is compared with the adaptive algorithm due to Alkhateeb, Ayach, Leus and Heath (2014) in the case with single radio frequency chain. Simulation results show that to achieve the same tracking performance, the proposed algorithm requires much lower signal-to-noise-ratio (SNR) and much fewer pilots than the other algorithm. Moreover, the change detection method can always detect abrupt changes with moderate number of pilots and SNR.

Connected through hyperedge HE-1 (induced by source paper "tracking position and orientation through millimeter wave lens mimo in 5g systems"):
  with members:
    - "optimal precoders for tracking the aod and aoa of a mmwave path"
    - "direct localization for massive mimo"
    - "error bounds for uplink and downlink 3d localization in 5g mmwave systems"
    - "multi user millimeter wave mimo with full dimensional lens antenna array"
    - "compressive channel estimation and tracking for large arrays in mm wave picocells"
    - "joint device positioning and clock synchronization in 5g ultra dense networks"
    - "frequency selective hybrid precoding for limited feedback millimeter wave systems"
    - "fingerprinting based positioning in distributed massive mimo systems"

Connected through hyperedge HE-2 (induced by source paper "wireless terahertz system architectures for networks beyond 5g"):
  with members:
    - "low cost cognitive radios against spectrum scarcity"
    - "terahertz technologies to deliver optical network quality of experience in wireless systems beyond 5g"
    - "hybrid beamforming for massive mimo a survey"
    - "millimeter wave cellular networks a mac layer perspective"
    - "spatially common sparsity based adaptive channel estimation and feedback for fdd massive mimo"
    - "efficient scheduling and power allocation for d2d assisted wireless caching networks"
    - "an overview of load balancing in hetnets old myths and open problems"
    - "channel estimation and hybrid precoding for millimeter wave cellular systems"

Connected through hyperedge HE-3 (induced by source paper "efficient beam training and channel estimation for millimeter wave communications under mobility"):
  with members:
    - "compressive channel estimation and tracking for large arrays in mm wave picocells"
    - "an overview of signal processing techniques for millimeter wave mimo systems"
    - "tracking mm wave channel dynamics fast beam training strategies under mobility"
    - "compressed sensing for wireless communications useful tips and tricks"
    - "a survey of millimeter wave mmwave communications for 5g opportunities and challenges"
    - "training beam sequence design for millimeter wave mimo systems a pomdp framework"
    - "channel estimation and hybrid precoding for millimeter wave cellular systems"
    - "spatially sparse precoding in millimeter wave mimo systems"

Connected through hyperedge HE-4 (induced by source paper "low complexity adaptive beam and channel tracking for mobile mmwave communications"):
  with members:
    - "millimeter wave channel estimation via exploiting joint sparse and low rank structures"
    - "hybrid beamforming for massive mimo a survey"
    - "channel estimation and hybrid precoding for millimeter wave cellular systems"
    - "five disruptive technology directions for 5g"

Connected through hyperedge HE-5 (induced by source paper "fast analog beam tracking in phased antenna arrays theory and performance"):
  with members:
    - "how to mobilize mmwave a joint beam and channel tracking approach"
    - "communication computing and caching for mobile vr delivery modeling and trade off"
    - "new beam tracking technique for millimeter wave band communications"
    - "an overview of signal processing techniques for millimeter wave mimo systems"
    - "enabling uav cellular with millimeter wave communication potentials and approaches"
    - "tracking mm wave channel dynamics fast beam training strategies under mobility"
    - "hybrid beamforming for massive mimo a survey"
    - "limited feedback hybrid precoding for multi user millimeter wave systems"

Connected through hyperedge HE-6 (induced by source paper "crlb calculations for joint aoa aod and multipath gain estimation in millimeter wave wireless networks"):
  with members:
    - "new beam tracking technique for millimeter wave band communications"
    - "channel estimation and hybrid precoding for millimeter wave cellular systems"

Connected through hyperedge HE-7 (induced by source paper "mobile millimeter wave channel acquisition tracking and abrupt change detection"):
  with members:
    - "28 ghz millimeter wave ultrawideband small scale fading models in wireless channels"
    - "mimo channel modeling and capacity analysis for 5g millimeter wave wireless systems"
    - "channel estimation and hybrid precoding for millimeter wave cellular systems"
    - "what will 5g be"
    - "spatially sparse precoding in millimeter wave mimo systems"
    - "millimeter wave channel modeling and cellular capacity evaluation"
    - "five disruptive technology directions for 5g"
    - "millimeter wave beamforming for wireless backhaul and access in small cell networks"

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)