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 user selection for mimo broadcast channels"
  Abstract: In this paper, a downlink communication system, in which a Base Station (BS) equipped with $M$ antennas communicates with $N$ users each equipped with $K$ receive antennas, is considered. An efficient suboptimum algorithm is proposed for selecting a set of users in order to maximize the sum-rate throughput of the system. For the asymptotic case when $N$ tends to infinity, the necessary and sufficient conditions in order to achieve the maximum sum-rate throughput, such that the difference between the achievable sum-rate and the maximum value approaches zero, is derived. The complexity of our algorithm is investigated in terms of the required amount of feedback from the users to the base station, as well as the number of searches required for selecting the users. It is shown that the proposed method is capable of achieving a large portion of the sum-rate capacity, with a very low complexity.

Connected through hyperedge HE-1 (induced by source paper "an overview on resource allocation techniques for multi user mimo systems"):
  with members:
    - "low complexity downlink user selection for massive mimo systems"
    - "alternating minimization algorithms for hybrid precoding in millimeter wave mimo systems"
    - "an overview of signal processing techniques for millimeter wave mimo systems"
    - "user association in 5g networks a survey and an outlook"
    - "cell free massive mimo versus small cells"
    - "mu mimo mac protocols for wireless local area networks a survey"
    - "on the number of rf chains and phase shifters and scheduling design with hybrid analog digital beamforming"
    - "hybrid digital and analog beamforming design for large scale antenna arrays"

Connected through hyperedge HE-2 (induced by source paper "symbol level and multicast precoding for multiuser multiantenna downlink a survey classification and challenges"):
  with members:
    - "channel estimation and performance analysis of one bit massive mimo systems"
    - "an overview on resource allocation techniques for multi user mimo systems"
    - "spatio temporal waveform design for multiuser massive mimo downlink with 1 bit receivers"
    - "joint beamforming and broadcasting in massive mimo"
    - "coordinate update algorithms for robust power loading for the mu miso downlink with outage constraints"
    - "energy efficient symbol level precoding in multiuser miso based on relaxed detection region"
    - "robust transmission in downlink multiuser miso systems a rate splitting approach"
    - "adaptive pilot clustering in heterogeneous massive mimo networks"

Connected through hyperedge HE-3 (induced by source paper "coordinated regularized zero forcing precoding for multicell miso systems with limited feedback"):
  with members:
    - "linear precoding based on polynomial expansion large scale multi cell mimo systems"
    - "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"
    - "large system analysis of linear precoding in correlated miso broadcast channels under limited feedback"
    - "base station cooperation with feedback optimization a large system analysis"
    - "adaptive limited feedback for sum rate maximizing beamforming in cooperative multicell systems"
    - "adaptive spatial intercell interference cancellation in multicell wireless networks"
    - "mimo broadcast channels with finite rate feedback"

Connected through hyperedge HE-4 (induced by source paper "opportunistic scheduling for full duplex uplink downlink networks"):
  with members:
    - "distributed full duplex via wireless side channels bounds and protocols"

Connected through hyperedge HE-5 (induced by source paper "receive combining vs multi stream multiplexing in downlink systems with multi antenna users"):
  with members:
    - "scaling up mimo opportunities and challenges with very large arrays"
    - "limited feedback based block diagonalization for the mimo broadcast channel"
    - "antenna combining for the mimo downlink channel"
    - "multi user diversity vs accurate channel feedback for mimo broadcast channels"
    - "multiuser mimo achievable rates with downlink training and channel state feedback"
    - "mimo broadcast channels with finite rate feedback"
    - "quantization bounds on grassmann manifolds and applications to mimo communications"

Connected through hyperedge HE-6 (induced by source paper "large deviation delay analysis of queue aware multi user mimo systems with two timescale mobile driven feedback"):
  with members:
    - "queue aware dynamic clustering and power allocation for network mimo systems via distributed stochastic learning"
    - "stability and delay of zero forcing sdma with limited feedback"
    - "delay sensitive distributed power and transmission threshold control for s aloha network with finite state markov fading channels"

Connected through hyperedge HE-7 (induced by source paper "the ergodic capacity of the multiple access channel under distributed scheduling order optimality of linear receivers"):
  with members:
    - "opportunistic scheduling in heterogeneous networks distributed algorithms and system capacity"
    - "opportunistic scheduling and beamforming for mimo sdma downlink systems with linear combining"

Connected through hyperedge HE-8 (induced by source paper "multi user diversity vs accurate channel state information in mimo downlink channels"):
  with members:
    - "capacity of a multiple antenna fading channel with a quantized precoding matrix"
    - "antenna combining for the mimo downlink channel"
    - "space division multiple access with a sum feedback rate constraint"
    - "multiuser mimo achievable rates with downlink training and channel state feedback"
    - "mimo broadcast channels with finite rate feedback"
    - "on the capacity of fading mimo broadcast channels with imperfect transmitter side information"
    - "performance of orthogonal beamforming for sdma with limited feedback"

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)