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: "precoding by pairing subchannels to increase mimo capacity with discrete input alphabets"
  Abstract: We consider Gaussian multiple-input multiple-output (MIMO) channels with discrete input alphabets. We propose a non diagonal precoder based on the X-Codes in to increase the mutual information. The MIMO channel is transformed into a set of parallel subchannels using singular value decomposition (SVD) and X-Codes are then used to pair the subchannels. X-Codes are fully characterized by the pairings and a 2 × 2 real rotation matrix for each pair (parameterized with a single angle). This precoding structure enables us to express the total mutual information as a sum of the mutual information of all the pairs. The problem of finding the optimal precoder with the above structure, which maximizes the total mutual information, is solved by: i) optimizing the rotation angle and the power allocation within each pair and ii) finding the optimal pairing and power allocation among the pairs. It is shown that the mutual information achieved with the proposed pairing scheme is very close to that achieved with the optimal pre coder by Cruz et al., and is significantly better than Mercury/waterfllling strategy by Lozano et al. Our approach greatly simplifies both the precoder optimization and the detection complexity, making it suitable for practical applications.

Connected through hyperedge HE-1 (induced by source paper "a survey on mimo transmission with discrete input signals technical challenges advances and future trends"):
  with members:
    - "asymptotic performance analysis of a k hop amplify and forward relay mimo channel"
    - "iterative distributed minimum total mse approach for secure communications in mimo interference channels"
    - "asymptotic analysis of su mimo channels with transmitter noise and mismatched joint decoding"
    - "secure massive mimo transmission with an active eavesdropper"
    - "interference aligned space time transmission with diversity for the 2 times 2 x network"
    - "space time encoded miso broadcast channel with outdated csit an error rate and diversity performance analysis"
    - "high snr asymptotics of mutual information for discrete constellations with applications to bicm"
    - "differential distributed space time coding with imperfect synchronization in frequency selective channels"

Connected through hyperedge HE-2 (induced by source paper "secure transmission with large numbers of antennas and finite alphabet inputs"):
  with members:
    - "physical layer security for spectrum sharing systems"
    - "linear precoding of data and artificial noise in secure massive mimo systems"
    - "a survey on wireless security technical challenges recent advances and future trends"
    - "secure massive mimo transmission with an active eavesdropper"
    - "large scale mimo relaying techniques for physical layer security af or df"
    - "multi antenna relay aided wireless physical layer security"
    - "low complexity mimo precoding with discrete signals and statistical csi"
    - "linear precoding for the mimo multiple access channel with finite alphabet inputs and statistical csi"

Connected through hyperedge HE-3 (induced by source paper "low complexity mimo precoding for finite alphabet signals"):
  with members:
    - "linear precoding for mimo channels with qam constellations and reduced complexity"
    - "secure massive mimo transmission with an active eavesdropper"
    - "transmit designs for the mimo broadcast channel with statistical csi"
    - "five disruptive technology directions for 5g"
    - "scaling up mimo opportunities and challenges with very large arrays"
    - "on capacity of large scale mimo multiple access channels with distributed sets of correlated antennas"
    - "statistical eigenmode transmission over jointly correlated mimo channels"
    - "on optimal precoding in linear vector gaussian channels with arbitrary input distribution"

Connected through hyperedge HE-4 (induced by source paper "large scale mimo secure transmission with finite alphabet inputs"):
  with members:
    - "secure massive mimo transmission with an active eavesdropper"
    - "linear precoding for the mimo multiple access channel with finite alphabet inputs and statistical csi"
    - "massive mimo for next generation wireless systems"
    - "linear precoder design for mimo interference channels with finite alphabet signaling"
    - "on secrecy rate analysis of mimo wiretap channels driven by finite alphabet input"
    - "secure communication in the low snr regime"

Connected through hyperedge HE-5 (induced by source paper "low complexity mimo precoding with discrete signals and statistical csi"):
  with members:
    - "linear precoding for mimo channels with qam constellations and reduced complexity"
    - "secure massive mimo transmission with an active eavesdropper"
    - "linear precoding for the mimo multiple access channel with finite alphabet inputs and statistical csi"
    - "secure massive mimo transmission in the presence of an active eavesdropper"
    - "transmit designs for the mimo broadcast channel with statistical csi"
    - "linear precoder design for mimo interference channels with finite alphabet signaling"
    - "on capacity of large scale mimo multiple access channels with distributed sets of correlated antennas"
    - "statistical eigenmode transmission over jointly correlated mimo channels"

Connected through hyperedge HE-6 (induced by source paper "oblivious transfer over wireless channels"):
  with members:
    - "the oblivious transfer capacity of the wiretapped binary erasure channel"
    - "information spectrum approach to strong converse theorems for degraded wiretap channels"
    - "semantically secure lattice codes for the gaussian wiretap channel"
    - "achieving the secrecy capacity of wiretap channels using polar codes"
    - "mimo precoding with x and y codes"
    - "the secrecy capacity of the mimo wiretap channel"
    - "commitment capacity of discrete memoryless channels"

Connected through hyperedge HE-7 (induced by source paper "linear precoder design for mimo interference channels with finite alphabet signaling"):
  with members:
    - "mimo interference alignment over correlated channels with imperfect csi"
    - "user partitioning for less overhead in mimo interference channels"
    - "on beamformer design for multiuser mimo interference channels"
    - "statistical eigenmode transmission over jointly correlated mimo channels"
    - "degrees of freedom of the k user m times n mimo interference channel"
    - "gaussian interference channel capacity to within one bit"

Connected through hyperedge HE-8 (induced by source paper "bit interleaved coded multiple beamforming with perfect coding"):
  with members:
    - "reduced complexity decoding for bit interleaved coded multiple beamforming with constellation precoding"
    - "golden coded multiple beamforming"
    - "constellation precoded beamforming"
    - "constellation precoded multiple beamforming"
    - "mimo precoding with x and y codes"
    - "reduced complexity sphere decoding"
    - "bit interleaved coded multiple beamforming with constellation precoding"
    - "diversity analysis of bit interleaved coded multiple beamforming"

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)