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: "vandermonde frequency division multiplexing for cognitive radio"
  Abstract: We consider a cognitive radio scenario where a primary and a secondary user wish to communicate with their corresponding receivers simultaneously over frequency selective channels. Under realistic assumptions that the secondary transmitter has no side information about the primary's message and each transmitter knows only its local channels, we propose a Vandermonde precoder that cancels the interference from the secondary user by exploiting the redundancy of a cyclic prefix. Our numerical examples show that VFDM, with an appropriate design of the input covariance, enables the secondary user to achieve a considerable rate while generating zero interference to the primary user.

Connected through hyperedge HE-1 (induced by source paper "cognitive orthogonal precoder for two tiered networks deployment"):
  with members:
    - "exploiting interference alignment in multi cell cooperative ofdma resource allocation"
    - "optimal channel training in uplink network mimo systems"
    - "interference alignment for the k user mimo interference channel"
    - "from spectrum pooling to space pooling opportunistic interference alignment in mimo cognitive networks"
    - "adaptive limited feedback for sum rate maximizing beamforming in cooperative multicell systems"
    - "exploiting multi antennas for opportunistic spectrum sharing in cognitive radio networks"
    - "femtocell networks a survey"

Connected through hyperedge HE-2 (induced by source paper "vandermonde subspace frequency division multiplexing for two tiered cognitive radio networks"):
  with members:
    - "from spectrum pooling to space pooling opportunistic interference alignment in mimo cognitive networks"
    - "power control in two tier femtocell networks"
    - "secured communication over frequency selective fading channels a practical vandermonde precoding"
    - "mimo broadcast channel optimization under general linear constraints"
    - "femtocell networks a survey"

Connected through hyperedge HE-3 (induced by source paper "convolution operations arising from vandermonde matrices"):
  with members:
    - "eigen inference for energy estimation of multiple sources"
    - "finite dimensional statistical inference"
    - "field reconstruction in sensor networks with coverage holes and packet losses"
    - "channel capacity estimation using free probability theory"
    - "performance of linear field reconstruction techniques with noise and uncertain sensor locations"
    - "reconstruction of multidimensional signals from irregular noisy samples"
    - "free deconvolution for signal processing applications"

Connected through hyperedge HE-4 (induced by source paper "secured communication over frequency selective fading channels a practical vandermonde precoding"):
  with members:
    - "interference alignment for secrecy"
    - "secure transmission with multiple antennas ii the mimome wiretap channel"
    - "the secrecy capacity region of the gaussian mimo multi receiver wiretap channel"
    - "on the 3 receiver broadcast channel with degraded message sets and confidential messages"
    - "the secrecy capacity region of the gaussian mimo broadcast channel"
    - "the k receiver broadcast channel with confidential messages"
    - "discrete memoryless interference and broadcast channels with confidential messages secrecy rate regions"
    - "secrecy capacity of a class of broadcast channels with an eavesdropper"

Connected through hyperedge HE-5 (induced by source paper "opportunistic interference alignment in mimo interference channels"):
  with members:
    - "degrees of freedom region for the mimo x channel"

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)