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: "low rf complexity technologies to enable millimeter wave mimo with large antenna array for 5g wireless communications"
  Abstract: Millimeter-wave (mmWave) MIMO with large antenna array has attracted considerable interests from academic and industry communities, as it can provide larger bandwidth and higher spectrum efficiency. However, with hundreds of antennas, the number of radio frequency (RF) chains required by mmWave MIMO is also huge, leading to unaffordable hardware cost and power consumption in practice. In this paper, we investigate low RF-complexity technologies to solve this bottleneck. We first review the evolution of low RF-complexity technologies from microwave frequencies to mmWave frequencies. Then, we discuss two promising low RF-complexity technologies for mmWave MIMO systems in detail, i.e., phased array based hybrid precoding (PAHP) and lens array based hybrid precoding (LAHP), including their principles, advantages, challenges, and recent results. We compare the performance of these two technologies to draw some insights about how they can be deployed in practice. Finally, we conclude this paper and point out some future research directions in this area.

Connected through hyperedge HE-1 (induced by source paper "artificial intelligence enabled wireless networking for 5g and beyond recent advances and future challenges"):
  with members:
    - "deep learning based channel estimation for beamspace mmwave massive mimo systems"
    - "wireless communications in the era of big data"

Connected through hyperedge HE-2 (induced by source paper "a tutorial on beam management for 3gpp nr at mmwave frequencies"):
  with members:
    - "statistical blockage modeling and robustness of beamforming in millimeter wave systems"
    - "adaptive beamwidth selection for contention based access periods in millimeter wave wlans"
    - "standalone and non standalone beam management for 3gpp nr at mmwaves"
    - "study of realistic antenna patterns in 5g mmwave cellular scenarios"
    - "initial access frameworks for 3gpp nr at mmwave frequencies"
    - "on the beamformed broadcast signaling for millimeter wave cell discovery performance analysis and design insight"
    - "caching meets millimeter wave communications for enhanced mobility management in 5g networks"
    - "improved handover through dual connectivity in 5g mmwave mobile networks"

Connected through hyperedge HE-3 (induced by source paper "fully partially connected hybrid beamforming architectures for mmwave mu mimo"):
  with members:
    - "hybrid precoding architecture for massive multiuser mimo with dissipation sub connected or fully connected structures"
    - "on the energy efficiency of mimo hybrid beamforming for millimeter wave systems with nonlinear power amplifiers"
    - "hybrid beamforming based on implicit channel state information for millimeter wave links"
    - "fully connected vs sub connected hybrid precoding architectures for mmwave mu mimo"
    - "millimeter wave mimo prototype measurements and experimental results"
    - "hybrid analog digital beamforming for massive mimo systems"
    - "frequency domain compressive channel estimation for frequency selective hybrid mmwave mimo systems"
    - "a robust time domain beam alignment scheme for multi user wideband mmwave systems"

Connected through hyperedge HE-4 (induced by source paper "intelligent reflecting and transmitting surface aided millimeter wave massive mimo"):
  with members:
    - "a novel communication paradigm for high capacity and security via programmable indoor wireless environments in next generation wireless systems"
    - "intelligent reflecting surfaces for free space optical communications"
    - "feedback aware precoding for millimeter wave massive mimo systems"
    - "energy efficiency of mmwave massive mimo precoding with low resolution dacs"
    - "intelligent reflecting surface enhanced wireless network via joint active and passive beamforming"
    - "scalable and energy efficient millimeter massive mimo architectures reflect array and transmit array antennas"
    - "intelligent reflecting surface enhanced wireless network joint active and passive beamforming design"
    - "c ran with hybrid rf fso fronthaul links joint optimization of rf time allocation and fronthaul compression"

Connected through hyperedge HE-5 (induced by source paper "millimeter wave massive mimo systems relying on generalized sub array connected hybrid precoding"):
  with members:
    - "spatial lobes division based low complexity hybrid precoding and diversity combining for mmwave iot systems"
    - "non uniform quantization codebook based hybrid precoding to reduce feedback overhead in millimeter wave mimo systems"
    - "on the energy efficiency of mimo hybrid beamforming for millimeter wave systems with nonlinear power amplifiers"
    - "stepwise transmit antenna selection in downlink massive multiuser mimo"
    - "downlink precoding with mixed statistical and imperfect instantaneous csi for massive mimo systems"
    - "pilot power allocation through user grouping in multi cell massive mimo systems"
    - "codebook based hybrid precoding for millimeter wave multiuser systems"
    - "alternating minimization algorithms for hybrid precoding in millimeter wave mimo systems"

Connected through hyperedge HE-6 (induced by source paper "unequally sub connected architecture for hybrid beamforming in massive mimo systems"):
  with members:
    - "energy efficient transceiver design for hybrid sub array architecture mimo systems"
    - "cell coverage extension with orthogonal random precoding for massive mimo systems"
    - "hybrid beamforming for large antenna arrays with phase shifter selection"
    - "an overview of signal processing techniques for millimeter wave mimo systems"
    - "on the number of rf chains and phase shifters and scheduling design with hybrid analog digital beamforming"
    - "dynamic subarrays for hybrid precoding in wideband mmwave mimo systems"
    - "massive mimo combining with switches"
    - "limited feedback hybrid precoding for multi user millimeter wave systems"

Connected through hyperedge HE-7 (induced by source paper "codebook based max min energy efficient resource allocation for uplink mmwave mimo noma systems"):
  with members:
    - "capacity achieving mimo noma iterative lmmse detection"
    - "energy efficient power allocation in uplink mmwave massive mimo with noma"
    - "rate splitting multiple access for downlink communication systems bridging generalizing and outperforming sdma and noma"
    - "power domain non orthogonal multiple access noma in 5g systems potentials and challenges"
    - "non orthogonal multiple access in large scale heterogeneous networks"
    - "energy efficient power allocation in millimeter wave massive mimo with non orthogonal multiple access"
    - "resource allocation for downlink noma systems key techniques and open issues"
    - "capacity comparison between mimo noma and mimo oma with multiple users in a cluster"

Connected through hyperedge HE-8 (induced by source paper "mmwave amplify and forward mimo relay networks with hybrid precoding combining design"):
  with members:
    - "hybrid block diagonalization for massive multiuser mimo systems"
    - "spatially sparse precoding in millimeter wave mimo systems"
    - "transceiver design for dual hop nonregenerative mimo ofdm relay systems under channel uncertainties"
    - "distributed beamforming in wireless multiuser relay interference networks with quantized feedback"
    - "network beamforming using relays with perfect channel information"

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)