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: "sparse beamforming and user centric clustering for downlink cloud radio access network"
  Abstract: This paper considers a downlink cloud radio access network (C-RAN) in which all the base-stations (BSs) are connected to a central computing cloud via digital backhaul links with finite capacities. Each user is associated with a user-centric cluster of BSs; the central processor shares the user's data with the BSs in the cluster, which then cooperatively serve the user through joint beamforming. Under this setup, this paper investigates the user scheduling, BS clustering and beamforming design problem from a network utility maximization perspective. Differing from previous works, this paper explicitly considers the per-BS backhaul capacity constraints. We formulate the network utility maximization problem for the downlink C-RAN under two different models depending on whether the BS clustering for each user is dynamic or static over different user scheduling time slots. In the former case, the user-centric BS cluster is dynamically optimized for each scheduled user along with the beamforming vector in each time-frequency slot, while in the latter case the user-centric BS cluster is fixed for each user and we jointly optimize the user scheduling and the beamforming vector to account for the backhaul constraints. In both cases, the nonconvex per-BS backhaul constraints are approximated using the reweighted l1-norm technique. This approximation allows us to reformulate the per-BS backhaul constraints into weighted per-BS power constraints and solve the weighted sum rate maximization problem through a generalized weighted minimum mean square error approach. This paper shows that the proposed dynamic clustering algorithm can achieve significant performance gain over existing naive clustering schemes. This paper also proposes two heuristic static clustering schemes that can already achieve a substantial portion of the gain.

Connected through hyperedge HE-1 (induced by source paper "secure millimeter wave cloud radio access networks relying on microwave multicast fronthaul"):
  with members:
    - "hybrid precoding based millimeter wave massive mimo noma with simultaneous wireless information and power transfer"
    - "optimized base station cache allocation for cloud radio access network with multicast backhaul"
    - "safeguarding millimeter wave communications against randomly located eavesdroppers"
    - "energy efficient power allocation in millimeter wave massive mimo with non orthogonal multiple access"
    - "adaptive coding and modulation for large scale antenna array based aeronautical communications in the presence of co channel interference"
    - "robust an aided beamforming and power splitting design for secure miso cognitive radio with swipt"
    - "energy efficient joint congestion control and resource optimization in heterogeneous cloud radio access networks"
    - "content centric sparse multicast beamforming for cache enabled cloud ran"

Connected through hyperedge HE-2 (induced by source paper "caching at base stations with multi cluster multicast wireless backhaul via accelerated first order algorithm"):
  with members:
    - "caching at base stations with heterogeneous user demands and spatial locality"
    - "optimized base station cache allocation for cloud radio access network with multicast backhaul"
    - "modeling analysis and optimization of coded caching in small cell networks"
    - "noisy broadcast networks with receiver caching"
    - "caching at the wireless edge design aspects challenges and future directions"
    - "content centric sparse multicast beamforming for cache enabled cloud ran"
    - "cloud radio access network virtualizing wireless access for dense heterogeneous systems"
    - "cloud radio access networks with coded caching"

Connected through hyperedge HE-3 (induced by source paper "interference mitigation via rate splitting and common message decoding in cloud radio access networks"):
  with members:
    - "energy efficiency of rate splitting multiple access and performance benefits over sdma and noma"
    - "rate splitting for multi antenna non orthogonal unicast and multicast transmission"
    - "cross layer design for downlink multihop cloud radio access networks with network coding"
    - "content centric sparse multicast beamforming for cache enabled cloud ran"
    - "optimality of treating interference as noise a combinatorial perspective"
    - "fronthaul constrained cloud radio access networks insights and challenges"
    - "cloud radio access network virtualizing wireless access for dense heterogeneous systems"
    - "cloud radio access networks with coded caching"

Connected through hyperedge HE-4 (induced by source paper "joint uplink and downlink transmissions in user centric ofdma cloud ran"):
  with members:
    - "joint precoding and rrh selection for user centric green mimo c ran"
    - "fronthaul limited uplink ofdma in ultra dense cran with hybrid decoding"
    - "joint millimeter wave fronthaul and ofdma resource allocation in ultra dense cran"
    - "green ofdma resource allocation in cache enabled cran"
    - "why to decouple the uplink and downlink in cellular networks and how to do it"
    - "fronthaul constrained cloud radio access networks insights and challenges"
    - "coordinated scheduling for the downlink of cloud radio access networks"
    - "what will 5g be"

Connected through hyperedge HE-5 (induced by source paper "joint sparse beamforming and power control for large scale das with network assistant full duplex"):
  with members:
    - "performance of network assisted full duplex for cell free massive mimo"
    - "fractional programming for communication systems part ii uplink scheduling via matching"
    - "cross layer design for downlink multihop cloud radio access networks with network coding"
    - "analysis of massive mimo enabled downlink wireless backhauling for full duplex small cells"
    - "energy efficiency of downlink transmission strategies for cloud radio access networks"
    - "d2d enhanced heterogeneous cellular networks with dynamic tdd"
    - "compflex comp for in band wireless full duplex"
    - "on the spectral efficiency of full duplex small cell wireless systems"

Connected through hyperedge HE-6 (induced by source paper "coherent communications in self organizing networks with distributed beamforming"):
  with members:
    - "channel estimation and hybrid precoding for millimeter wave cellular systems"
    - "distributed stochastic power control in ad hoc networks a nonconvex optimization case"
    - "distributed transmit beamforming using feedback control"
    - "collaborative beamforming for distributed wireless ad hoc sensor networks"

Connected through hyperedge HE-7 (induced by source paper "deep reinforcement learning based mode selection and resource management for green fog radio access networks"):
  with members:
    - "learning to optimize training deep neural networks for interference management"
    - "on reducing iot service delay via fog offloading"
    - "layered group sparse beamforming for cache enabled green wireless networks"
    - "an evolutionary game for user access mode selection in fog radio access networks"
    - "deep reinforcement learning an overview"
    - "a deep reinforcement learning based framework for content caching"
    - "energy efficient resource allocation optimization for multimedia heterogeneous cloud radio access networks"
    - "fog computing based radio access networks issues and challenges"

Connected through hyperedge HE-8 (induced by source paper "robust beamforming with pilot reuse scheduling in a heterogeneous cloud radio access network"):
  with members:
    - "joint precoding and rrh selection for user centric green mimo c ran"
    - "joint user selection and energy minimization for ultra dense multi channel c ran with incomplete csi"
    - "energy efficient resource allocation optimization for multimedia heterogeneous cloud radio access networks"
    - "robust pilot decontamination based on joint angle and power domain discrimination"
    - "energy efficient joint congestion control and resource optimization in heterogeneous cloud radio access networks"
    - "energy efficiency of downlink transmission strategies for cloud radio access networks"
    - "contract based interference coordination in heterogeneous cloud radio access networks"
    - "coordinated shared spectrum precoding with distributed csit"

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)