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: "message passing algorithm for distributed downlink regularized zero forcing beamforming with cooperative base stations"
  Abstract: Base station (BS) cooperation can turn unwanted interference to useful signal energy for enhancing system performance. In the cooperative downlink, zero-forcing beamforming (ZFBF) with a simple scheduler is well known to obtain nearly the performance of the capacity-achieving dirty-paper coding. However, the centralized ZFBF approach is prohibitively complex as the network size grows. In this paper, we devise message passing algorithms for realizing the regularized ZFBF (RZFBF) in a distributed manner using belief propagation. In the proposed methods, the overall computational cost is decomposed into many smaller computation tasks carried out by groups of neighboring BSs and communications is only required between neighboring BSs. More importantly, some exchanged messages can be computed based on channel statistics rather than instantaneous channel state information, leading to significant reduction in computational complexity. Simulation results demonstrate that the proposed algorithms converge quickly to the exact RZFBF and much faster compared to conventional methods.

Connected through hyperedge HE-1 (induced by source paper "an overview of transmission theory and techniques of large scale antenna systems for 5g wireless communications"):
  with members:
    - "channel acquisition for massive mimo ofdm with adjustable phase shift pilots"
    - "mixed adc massive mimo detectors performance analysis and design optimization"
    - "performance analysis and location optimization for massive mimo systems with circularly distributed antennas"
    - "uplink achievable rate for massive mimo systems with low resolution adc"
    - "spatially common sparsity based adaptive channel estimation and feedback for fdd massive mimo"
    - "a stochastic geometry framework for analyzing pairwise cooperative cellular networks"
    - "structured compressive sensing based superimposed pilot design in downlink large scale mimo systems"
    - "fractional pilot reuse in massive mimo systems"

Connected through hyperedge HE-2 (induced by source paper "large system analysis of cognitive radio network via partially projected regularized zero forcing precoding"):
  with members:
    - "super resolution sparse mimo ofdm channel estimation based on spatial and temporal correlations"
    - "joint beamforming and power control in coordinated multicell max min duality effective network and large system transition"
    - "multi pair amplify and forward relaying with very large antenna arrays"
    - "large system analysis of cooperative multi cell downlink transmission via regularized channel inversion with imperfect csit"
    - "optimal power allocation and user loading for multiuser miso channels with regularized channel inversion"
    - "on capacity of large scale mimo multiple access channels with distributed sets of correlated antennas"
    - "large system analysis of linear precoding in miso broadcast channels with confidential messages"
    - "random beamforming over quasi static and fading channels a deterministic equivalent approach"

Connected through hyperedge HE-3 (induced by source paper "ber analysis of the box relaxation for bpsk signal recovery"):
  with members:
    - "precise error analysis of regularized m estimators in high dimensions"
    - "optimality of large mimo detection via approximate message passing"
    - "the generalized lasso with non linear observations"
    - "a framework to characterize performance of lasso algorithms"
    - "channel hardening exploiting message passing chemp receiver in large scale mimo systems"
    - "the squared error of generalized lasso a precise analysis"
    - "energy and spectral efficiency of very large multiuser mimo systems"

Connected through hyperedge HE-4 (induced by source paper "asymptotic rate analysis of downlink multi user systems with co located and distributed antennas"):
  with members:
    - "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"
    - "transmission schemes based on sum rate analysis in distributed antenna 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)