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: "massive mimo with spatially correlated rician fading channels"
  Abstract: This paper considers multi-cell massive multiple-input multiple-output systems, where the channels are spatially correlated Rician fading. The channel model is composed of a deterministic line-of-sight path and a stochastic non-line-of-sight component describing a practical spatially correlated multipath environment. We derive the statistical properties of the minimum mean squared error (MMSE), element-wise MMSE, and least-square channel estimates for this model. Using these estimates for maximum ratio combining and precoding, rigorous closed-form uplink (UL) and downlink (DL) achievable spectral efficiency (SE) expressions are derived and analyzed. The asymptotic SE behavior, when using the different channel estimators, are also analyzed. The numerical results show that the SE is higher when using the MMSE estimator than that of the other estimators, and the performance gap increases with the number of antennas.

Connected through hyperedge HE-1 (induced by source paper "joint power control and lsfd for wireless powered cell free massive mimo"):
  with members:
    - "max min fair wireless powered cell free massive mimo for uncorrelated rician fading channels"
    - "optimal downlink transmission for cell free swipt massive mimo systems with active eavesdropping"
    - "scalability aspects of cell free massive mimo"
    - "scalable cell free massive mimo systems"
    - "performance of cell free massive mimo with rician fading and phase shifts"
    - "multiple antenna technologies for beyond 5g"
    - "making cell free massive mimo competitive with mmse processing and centralized implementation"
    - "massive mimo has unlimited capacity"

Connected through hyperedge HE-2 (induced by source paper "max min fair wireless powered cell free massive mimo for uncorrelated rician fading channels"):
  with members:
    - "optimal downlink transmission for cell free swipt massive mimo systems with active eavesdropping"
    - "scalability aspects of cell free massive mimo"
    - "performance of cell free massive mimo with rician fading and phase shifts"
    - "multiple antenna technologies for beyond 5g"
    - "making cell free massive mimo competitive with mmse processing and centralized implementation"
    - "optimization of power transfer efficiency and energy efficiency for wireless powered systems with massive mimo"
    - "green cell less design for rf wireless power transfer networks"
    - "performance of cell free massive mimo systems with mmse and lsfd receivers"

Connected through hyperedge HE-3 (induced by source paper "large scale fading precoding for maximizing the product of sinrs"):
  with members:
    - "joint user selection power allocation and precoding design with imperfect csit for multi cell mu mimo downlink systems"
    - "scalability aspects of cell free massive mimo"
    - "optimized power control for massive mimo with underlaid d2d communications"
    - "large scale fading decoding in cellular massive mimo systems with spatially correlated channels"
    - "performance of cell free massive mimo with rician fading and phase shifts"
    - "uplink massive mimo for channels with spatial correlation"
    - "a bilinear equalizer for massive mimo systems"
    - "massive mimo has unlimited capacity"

Connected through hyperedge HE-4 (induced by source paper "massive mimo with multi antenna users under jointly correlated ricean fading"):
  with members:
    - "massive mimo with multi antenna users when are additional user antennas beneficial"
    - "energy and spectral efficiency of very large multiuser mimo systems"

Connected through hyperedge HE-5 (induced by source paper "theoretical performance limits of massive mimo with uncorrelated rician fading channels"):
  with members:
    - "massive mimo has unlimited capacity"
    - "performance analysis of mixed adc massive mimo systems over rician fading channels"
    - "on the spectral efficiency of massive mimo systems with low resolution adcs"
    - "pilot contamination is not a fundamental asymptotic limitation in massive mimo"
    - "asymptotic analysis of multicell massive mimo over rician fading channels"
    - "achievable rate of rician large scale mimo channels with transceiver hardware impairments"
    - "massive mimo ten myths and one critical question"
    - "massive mimo with multi cell mmse processing exploiting all pilots for interference suppression"

Connected through hyperedge HE-6 (induced by source paper "spectral efficiency analysis of multi cell massive mimo systems with ricean fading"):
  with members:
    - "spectral efficiency analysis of cell free massive mimo systems with zero forcing detector"
    - "uplink spectral efficiency of massive mimo with spatially correlated rician fading"
    - "massive mimo has unlimited capacity"
    - "pilot power allocation through user grouping in multi cell massive mimo systems"
    - "asymptotic analysis of multicell massive mimo over rician fading channels"
    - "multipair full duplex relaying with massive arrays and linear processing"
    - "power scaling of uplink massive mimo systems with arbitrary rank channel means"
    - "massive mimo for maximal spectral efficiency how many users and pilots should be allocated"

Connected through hyperedge HE-7 (induced by source paper "lmmse receivers in uplink massive mimo systems with correlated rician fading"):
  with members:
    - "line of sight and pilot contamination effects on correlated multi cell massive mimo systems"
    - "impact of line of sight and unequal spatial correlation on uplink mu 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"

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)