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: "on the capacity achieving covariance matrix for frequency selective mimo channels using the asymptotic approach"
  Abstract: In this contribution, an algorithm for evaluating the capacity-achieving input covariance matrices for frequency selective Rayleigh MIMO channels is proposed. In contrast with the flat fading Rayleigh cases, no closed-form expressions for the eigenvectors of the optimum input covariance matrix are available. Classically, both the eigenvectors and eigenvalues are computed numerically and the corresponding optimization algorithms remain computationally very demanding. In this paper, it is proposed to optimize (w.r.t. the input covariance matrix) a large system approximation of the average mutual information derived by Moustakas and Simon. An algorithm based on an iterative water filling scheme is proposed, and its convergence is studied. Numerical simulation results show that, even for a moderate number of transmit and receive antennas, the new approach provides the same results as direct maximization approaches of the average mutual information.

Connected through hyperedge HE-1 (induced by source paper "energy efficiency optimization for downlink massive mimo with statistical csit"):
  with members:
    - "beam domain secure transmission for massive mimo communications"
    - "fractional programming for communication systems part i power control and beamforming"
    - "energy efficient multicell multigroup multicasting with joint beamforming and antenna selection"
    - "fdd massive mimo via ul dl channel covariance extrapolation and active channel sparsification"
    - "network deployment for maximal energy efficiency in uplink with multislope path loss"
    - "energy efficient beam coordination strategies with rate dependent processing power"
    - "bdma for millimeter wave terahertz massive mimo transmission with per beam synchronization"
    - "free deterministic equivalents for the analysis of mimo multiple access channel"

Connected through hyperedge HE-2 (induced by source paper "beam domain secure transmission for massive mimo communications"):
  with members:
    - "free deterministic equivalents for the analysis of mimo multiple access channel"
    - "linear precoding of data and artificial noise in secure massive mimo systems"
    - "massive mimo ten myths and one critical question"
    - "secure communications in millimeter wave ad hoc networks"
    - "pilot reuse for massive mimo transmission over spatially correlated rayleigh fading channels"
    - "massive mimo for next generation wireless systems"
    - "downlink training techniques for fdd massive mimo systems open loop and closed loop training with memory"
    - "principles of physical layer security in multiuser wireless networks a survey"

Connected through hyperedge HE-3 (induced by source paper "free deterministic equivalents for the analysis of mimo multiple access channel"):
  with members:
    - "channel acquisition for massive mimo ofdm with adjustable phase shift pilots"
    - "an overview of transmission theory and techniques of large scale antenna systems for 5g wireless communications"
    - "secure massive mimo transmission with an active eavesdropper"
    - "pilot reuse for massive mimo transmission over spatially correlated rayleigh fading channels"
    - "joint power and antenna selection optimization in large cloud radio access networks"
    - "pilot beam pattern design for channel estimation in massive mimo systems"
    - "massive mimo for next generation wireless systems"
    - "on capacity of large scale mimo multiple access channels with distributed sets of correlated antennas"

Connected through hyperedge HE-4 (induced by source paper "backing off from infinity performance bounds via concentration of spectral measure for random mimo channels"):
  with members:
    - "massive mimo for next generation wireless systems"
    - "bounds on the second order coding rate of the mimo rayleigh block fading channel"
    - "shannon meets nyquist capacity of sampled gaussian channels"
    - "scaling up mimo opportunities and challenges with very large arrays"
    - "on the distribution of mimo mutual information an in depth painleve based characterization"
    - "outage capacity for the optical mimo channel"
    - "network mimo with linear zero forcing beamforming large system analysis impact of channel estimation and reduced complexity scheduling"
    - "achieving massive mimo spectral efficiency with a not so large number of antennas"

Connected through hyperedge HE-5 (induced by source paper "on capacity of large scale mimo multiple access channels with distributed sets of correlated antennas"):
  with members:
    - "scaling up mimo opportunities and challenges with very large arrays"
    - "network mimo with linear zero forcing beamforming large system analysis impact of channel estimation and reduced complexity scheduling"
    - "large system analysis of linear precoding in correlated miso broadcast channels under limited feedback"
    - "a deterministic equivalent for the analysis of non gaussian correlated mimo multiple access channels"
    - "multi cell mimo downlink with cell cooperation and fair scheduling a large system limit analysis"
    - "massive mimo how many antennas do we need"
    - "a deterministic equivalent for the analysis of correlated mimo multiple access channels"
    - "optimal channel training in uplink network mimo systems"

Connected through hyperedge HE-6 (induced by source paper "sinr statistics of correlated mimo linear receivers"):
  with members:
    - "large system analysis of linear precoding in correlated miso broadcast channels under limited feedback"
    - "on the precoder design of flat fading mimo systems equipped with mmse receivers a large system approach"
    - "tails of random matrix diagonal elements the case of the wishart inverse"
    - "a deterministic equivalent for the analysis of correlated mimo multiple access channels"
    - "asymptotic performance of linear receivers in mimo fading channels"
    - "performance of mmse mimo receivers a large n analysis for correlated channels"
    - "ber and outage probability approximations for lmmse detectors on correlated mimo channels"
    - "a central limit theorem for the sinr at the lmmse estimator output for large dimensional signals"

Connected through hyperedge HE-7 (induced by source paper "a deterministic equivalent for the analysis of non gaussian correlated mimo multiple access channels"):
  with members:
    - "large system analysis of linear precoding in correlated miso broadcast channels under limited feedback"
    - "on the precoder design of flat fading mimo systems equipped with mmse receivers a large system approach"
    - "multi cell mimo downlink with cell cooperation and fair scheduling a large system limit analysis"
    - "asymptotic moments for interference mitigation in correlated fading channels"
    - "a deterministic equivalent for the analysis of correlated mimo multiple access channels"
    - "optimal channel training in uplink network mimo systems"
    - "random matrix model for nakagami hoyt fading"
    - "statistical mechanical analysis of the kronecker channel model for multiple input multiple output wireless communication"

Connected through hyperedge HE-8 (induced by source paper "iterative deterministic equivalents for the performance analysis of communication systems"):
  with members:
    - "random beamforming over quasi static and fading channels a deterministic equivalent approach"
    - "asymptotic capacity and optimal precoding in mimo multi hop relay networks"
    - "a deterministic equivalent for the analysis of correlated mimo multiple access channels"
    - "optimal channel training in uplink network mimo systems"
    - "ergodic capacity analysis of amplify and forward mimo dual hop systems"
    - "multi cell mimo downlink with fairness criteria the large system limit"
    - "a new approach for capacity analysis of large dimensional multi antenna channels"
    - "large n analysis of amplify and forward mimo relay channels with correlated rayleigh fading"

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)