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: "impact of line of sight and unequal spatial correlation on uplink mu mimo systems"
  Abstract: Closed-form approximations of the expected per-terminal signal-to-interference-plus-noise-ratio (SINR) and ergodic sum spectral efficiency of a multiuser multiple-input multiple-output system are presented. Our analysis assumes spatially correlated Ricean fading channels with maximum-ratio combining on the uplink. Unlike previous studies, our model accounts for the presence of unequal correlation matrices, unequal Rice factors, as well as unequal link gains to each terminal. The derived approximations lend themselves to useful insights, special cases and show the combined impact of line-of-sight (LoS) and correlated components. Numerical results show that while unequal correlation matrices enhance the system performance, the presence of strong LoS has an opposite effect. The approximations are general and remain insensitive to changes in the system dimensions, signal-to-noise-ratios, LoS levels, and correlation levels.

Connected through hyperedge HE-1 (induced by source paper "amplitude and phase estimation for absolute calibration of massive mimo front ends"):
  with members:
    - "a framework for over the air reciprocity calibration for tdd massive mimo systems"
    - "reciprocity calibration for massive mimo proposal modeling and validation"
    - "hybrid beamforming for massive mimo a survey"
    - "massive mimo in real propagation environments do all antennas contribute equally"
    - "massive mimo for next generation wireless systems"
    - "scalable synchronization and reciprocity calibration for distributed multiuser mimo"

Connected through hyperedge HE-2 (induced by source paper "massive mimo with spatially correlated rician fading channels"):
  with members:
    - "covariance matrix estimation for massive mimo"
    - "uplink spectral efficiency of massive mimo with spatially correlated rician fading"
    - "covariance matrix estimation in massive mimo"
    - "massive mimo pilot decontamination and channel interpolation via wideband sparse channel estimation"
    - "massive mimo with imperfect channel covariance information"
    - "asymptotic analysis of multicell massive mimo over rician fading channels"
    - "power scaling of uplink massive mimo systems with arbitrary rank channel means"
    - "massive mimo for next generation wireless systems"

Connected through hyperedge HE-3 (induced by source paper "lmmse receivers in uplink massive mimo systems with correlated rician fading"):
  with members:
    - "massive mimo with spatially correlated rician fading channels"
    - "line of sight and pilot contamination effects on correlated multi cell massive mimo systems"
    - "asymptotic analysis of multicell massive mimo over rician fading channels"
    - "achievable rate of rician large scale mimo channels with transceiver hardware impairments"
    - "power scaling of uplink massive mimo systems with arbitrary rank channel means"
    - "what will 5g be"
    - "large system analysis of linear precoding in correlated miso broadcast channels under limited feedback"
    - "optimal channel training in uplink network mimo systems"

Connected through hyperedge HE-4 (induced by source paper "regularized zero forcing precoding aided adaptive coding and modulation for large scale antenna array based air to air communications"):
  with members:
    - "adaptive coding and modulation for large scale antenna array based aeronautical communications in the presence of co channel interference"
    - "asymptotic analysis of multicell massive mimo over rician fading channels"
    - "antenna grouping based feedback compression for fdd based massive mimo systems"
    - "massive mimo for next generation wireless systems"
    - "large system analysis of cooperative multi cell downlink transmission via regularized channel inversion with imperfect csit"

Connected through hyperedge HE-5 (induced by source paper "uplink spectral efficiency of massive mimo with spatially correlated rician fading"):
  with members:
    - "asymptotic analysis of multicell massive mimo over rician fading channels"
    - "power scaling of uplink massive mimo systems with arbitrary rank channel means"
    - "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-6 (induced by source paper "rician k factor based analysis of xlos service probability in 5g outdoor ultra dense networks"):
  with members:
    - "direct localization for massive mimo"
    - "a novel unified expression for the capacity and bit error probability of wireless communication systems over generalized fading channels"
    - "downlink performance analysis for a generalized shotgun cellular system"

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)