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: "downlink multi antenna heterogeneous cellular network with load balancing"
  Abstract: We model and analyze heterogeneous cellular networks with multiple antenna BSs (multi-antenna HetNets) with K classes or tiers of base stations (BSs), which may differ in terms of transmit power, deployment density, number of transmit antennas, number of users served, transmission scheme, and path loss exponent. We show that the cell selection rules in multi-antenna HetNets may differ significantly from the single-antenna HetNets due to the possible differences in multi-antenna transmission schemes across tiers. While it is challenging to derive exact cell selection rules even for maximizing signal-to-interferenceplus-noise-ratio (SINR) at the receiver, we show that adding an appropriately chosen tier-dependent cell selection bias in the received power yields a close approximation. Assuming arbitrary selection bias for each tier, simple expressions for downlink coverage and rate are derived. For coverage maximization, the required selection bias for each tier is given in closed form. Due to this connection with biasing, multi-antenna HetNets may balance load more naturally across tiers in certain regimes compared to single-antenna HetNets, where a large cell selection bias is often needed to offload traffic to small cells.

Connected through hyperedge HE-1 (induced by source paper "sdn enabled mimo heterogeneous cooperative networks with flexible cell association"):
  with members:
    - "toward a realistic assessment of multiple antenna hcns residual additive transceiver hardware impairments and channel aging"
    - "downlink mimo hcns with residual transceiver hardware impairments"
    - "user association in 5g networks a survey and an outlook"
    - "an overview of load balancing in hetnets old myths and open problems"
    - "a tractable model for noncoherent joint transmission base station cooperation"
    - "what will 5g be"
    - "downlink mimo hetnets modeling ordering results and performance analysis"
    - "heterogeneous cellular networks with flexible cell association a comprehensive downlink sinr analysis"

Connected through hyperedge HE-2 (induced by source paper "hetnets coverage modeling and analysis over fox s mathcal h fading channels"):
  with members:
    - "unified analysis and optimization of d2d communications in cellular networks over fading channels"
    - "effect of densification on cellular network performance with bounded pathloss model"
    - "a stochastic geometric analysis of device to device communications operating over generalized fading channels"
    - "unified stochastic geometry modeling and analysis of cellular networks in los nlos and shadowed fading"
    - "success probability and area spectral efficiency in multiuser mimo hetnets"
    - "modeling and analysis of k tier downlink heterogeneous cellular networks"
    - "a novel unified expression for the capacity and bit error probability of wireless communication systems over generalized fading channels"
    - "a tractable approach to coverage and rate in cellular networks"

Connected through hyperedge HE-3 (induced by source paper "a unified framework for the tractable analysis of multi antenna wireless networks"):
  with members:
    - "3gpp inspired hetnet model using poisson cluster process sum product functionals and downlink coverage"
    - "coverage analysis for millimeter wave networks the impact of directional antenna arrays"
    - "a tractable framework for performance analysis of dense multi antenna networks"
    - "ergodic spectral efficiency in mimo cellular networks"
    - "asymptotics and approximation of the sir distribution in general cellular networks"
    - "success probability and area spectral efficiency in multiuser mimo hetnets"
    - "downlink cellular network analysis with multi slope path loss models"
    - "user centric intercell interference nulling for downlink small cell networks"

Connected through hyperedge HE-4 (induced by source paper "the stochastic geometry analyses of cellular networks with alpha stable self similarity"):
  with members:
    - "system level modeling and optimization of the energy efficiency in cellular networks a stochastic geometry framework"
    - "delivery secrecy tradeoff for cache enabled stochastic networks content placement optimization"
    - "self interference in full duplex multi user mimo channels"
    - "secrecy outage analysis for downlink transmissions in the presence of randomly located eavesdroppers"
    - "modeling and analysis of cellular networks using stochastic geometry a tutorial"
    - "analytical modeling of interference aware power control for the uplink of heterogeneous cellular networks"
    - "analysis of massive mimo enabled downlink wireless backhauling for full duplex small cells"
    - "the learning and prediction of application level traffic data in cellular networks"

Connected through hyperedge HE-5 (induced by source paper "ergodic spectral efficiency in mimo cellular networks"):
  with members:
    - "modeling and analysis of cellular networks using stochastic geometry a tutorial"
    - "enriched k tier hetnet model to enable the analysis of user centric small cell deployments"
    - "scaling laws for ergodic spectral efficiency in mimo poisson networks"
    - "wireless network signals with moderately correlated shadowing still appear poisson"
    - "gaussian approximation for the downlink interference in heterogeneous cellular networks"
    - "analytical tractability of hexagonal network model with random user location"
    - "asymptotics and approximation of the sir distribution in general cellular networks"
    - "an analytical framework for device to device communication in cellular networks"

Connected through hyperedge HE-6 (induced by source paper "heterogeneous cellular networks with los and nlos transmissions the role of massive mimo and small cells"):
  with members:
    - "modeling and analyzing millimeter wave cellular systems"
    - "downlink cellular network analysis with los nlos propagation and elevated base stations"
    - "performance impact of los and nlos transmissions in dense cellular networks"
    - "power allocation schemes for multicell massive mimo systems"
    - "massive mimo versus small cell systems spectral and energy efficiency comparison"
    - "energy efficient design of mimo heterogeneous networks with wireless backhaul"
    - "analyzing uplink sinr and rate in massive mimo systems using stochastic geometry"
    - "power scaling of uplink massive mimo systems with arbitrary rank channel means"

Connected through hyperedge HE-7 (induced by source paper "non orthogonal multiple access in large scale heterogeneous networks"):
  with members:
    - "massive non orthogonal multiple access for cellular iot potentials and limitations"
    - "modulation and multiple access for 5g networks"
    - "nonorthogonal multiple access in large scale underlay cognitive radio networks"
    - "enhancing the physical layer security of non orthogonal multiple access in large scale networks"
    - "cooperative non orthogonal multiple access with simultaneous wireless information and power transfer"
    - "the application of mimo to non orthogonal multiple access"
    - "user association and interference management in massive mimo hetnets"
    - "fairness for non orthogonal multiple access in 5g systems"

Connected through hyperedge HE-8 (induced by source paper "downlink and uplink decoupling in two tier heterogeneous networks with multi antenna base stations"):
  with members:
    - "a comparison study of coupled and decoupled uplink heterogeneous cellular networks"
    - "why to decouple the uplink and downlink in cellular networks and how to do it"
    - "analysis of the decoupled access for downlink and uplink in wireless heterogeneous networks"
    - "on stochastic geometry modeling of cellular uplink transmission with truncated channel inversion power control"
    - "joint rate and sinr coverage analysis for decoupled uplink downlink biased cell associations in hetnets"
    - "analysis and optimization of inter tier interference coordination in downlink multi antenna hetnets with offloading"
    - "capacity analysis of decoupled downlink and uplink access in 5g heterogeneous systems"
    - "downlink and uplink decoupling a disruptive architectural design for 5g networks"

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)