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: "space division multiple access with a sum feedback rate constraint"
  Abstract: On a multiantenna broadcast channel, simultaneous transmission to multiple users by joint beamforming and scheduling is capable of achieving high throughput, which grows double logarithmically with the number of users. The sum rate for channel state information (CSI) feedback, however, increases linearly with the number of users, reducing the effective uplink capacity. To address this problem, a novel space division multiple access (SDMA) design is proposed, where the sum feedback rate is upper bounded by a constant. This design consists of algorithms for CSI quantization, threshold-based CSI feedback, and joint beamforming and scheduling. The key feature of the proposed approach is the use of feedback thresholds to select feedback users with large channel gains and small CSI quantization errors such that the sum feedback rate constraint is satisfied. Despite this constraint, the proposed SDMA design is shown to achieve a sum capacity growth rate close to the optimal one. Moreover, the feedback overflow probability for this design is found to decrease exponentially with the difference between the allowable and the average sum feedback rates. Numerical results show that the proposed SDMA design is capable of attaining higher sum capacities than existing ones, even though the sum feedback rate is bounded.

Connected through hyperedge HE-1 (induced by source paper "modeling analysis and optimization of caching in multi antenna small cell networks"):
  with members:
    - "treating content delivery in multi antenna coded caching as general message sets transmission a dof region perspective"
    - "analysis and optimization of probabilistic caching in multi antenna small cell networks"
    - "caching policy toward maximal success probability and area spectral efficiency of cache enabled hetnets"
    - "modeling analysis and optimization of coded caching in small cell networks"
    - "wireless caching technical misconceptions and business barriers"
    - "a learning based approach to caching in heterogenous small cell networks"
    - "fundamental storage latency tradeoff in cache aided mimo interference networks"
    - "caching in wireless small cell networks a storage bandwidth tradeoff"

Connected through hyperedge HE-2 (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-3 (induced by source paper "analysis and optimization of probabilistic caching in multi antenna small cell networks"):
  with members:
    - "caching policy toward maximal success probability and area spectral efficiency of cache enabled hetnets"
    - "optimization and analysis of probabilistic caching in n tier heterogeneous networks"
    - "caching placement in stochastic wireless caching helper networks channel selection diversity via caching"
    - "cooperative caching and transmission design in cluster centric small cell networks"
    - "analysis on cache enabled wireless heterogeneous networks"
    - "optimal geographic caching in cellular networks"
    - "spectral efficiency of dynamic coordinated beamforming a stochastic geometry approach"
    - "user centric intercell interference nulling for downlink small cell networks"

Connected through hyperedge HE-4 (induced by source paper "spectral efficiency of dynamic coordinated beamforming a stochastic geometry approach"):
  with members:
    - "a stochastic geometry framework for analyzing pairwise cooperative cellular networks"
    - "asymptotic deployment gain a simple approach to characterize the sinr distribution in general cellular networks"
    - "a practical cooperative multicell mimo ofdma network based on rank coordination"
    - "coordinated multicast beamforming in multicell networks"
    - "network mimo with linear zero forcing beamforming large system analysis impact of channel estimation and reduced complexity scheduling"
    - "fundamental limits of cooperation"
    - "multi antenna communication in ad hoc networks achieving mimo gains with simo transmission"
    - "a tractable approach to coverage and rate in cellular networks"

Connected through hyperedge HE-5 (induced by source paper "mode selection in mu mimo downlink networks a physical layer security perspective"):
  with members:
    - "energy efficient power allocation for secure communications in large scale mimo relaying systems"
    - "principles of physical layer security in multiuser wireless networks a survey"
    - "performance analysis for physical layer security in multi antenna downlink networks with limited csi feedback"
    - "energy efficient optimization for physical layer security in multi antenna downlink networks with qos guarantee"
    - "multi mode transmission for the mimo broadcast channel with imperfect channel state information"
    - "robust beamforming for security in mimo wiretap channels with imperfect csi"
    - "secure transmission with multiple antennas ii the mimome wiretap channel"
    - "the secrecy capacity region of the gaussian mimo multi receiver wiretap channel"

Connected through hyperedge HE-6 (induced by source paper "optimal feedback rate sharing strategy in zero forcing mimo broadcast channels"):
  with members:
    - "an analytical framework for heterogeneous partial feedback design in heterogeneous multicell ofdma networks"
    - "random beamforming with heterogeneous users and selective feedback individual sum rate and individual scaling laws"
    - "multi user diversity vs accurate channel state information in mimo downlink channels"
    - "stochastic control of event driven feedback in multiantenna interference channels"
    - "a scalable limited feedback design for network mimo using per cell product codebook"
    - "mode switching for the multi antenna broadcast channel based on delay and channel quantization"
    - "adaptive limited feedback for sum rate maximizing beamforming in cooperative multicell systems"
    - "limited feedback based block diagonalization for the mimo broadcast channel"

Connected through hyperedge HE-7 (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"
    - "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"
    - "on the user selection for mimo broadcast channels"

Connected through hyperedge HE-8 (induced by source paper "mimo z channel interference management"):
  with members:
    - "parallel routing in mobile ad hoc networks"
    - "the diversity multiplexing tradeoff of the mimo z interference channel"
    - "mimo networks the effects of interference"
    - "on the degrees of freedom regions of two user mimo z and full interference channels with reconfigurable antennas"
    - "mimo z interference channels capacity under strong and noisy interference"

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)