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: "power allocation schemes for multicell massive mimo systems"
  Abstract: This paper investigates the sum-rate gains brought by power allocation strategies in multicell massive multipleinput multiple-output systems, assuming time-division duplex transmission. For both uplink and downlink, we derive tractable expressions for the achievable rate with zero-forcing receivers and precoders respectively. To avoid high complexity joint optimization across the network, we propose a scheduling mechanism for power allocation, where in a single time slot, only cells that do not interfere with each other adjust their transmit powers. Based on this, corresponding transmit power allocation strategies are derived, aimed at maximizing the sum rate per-cell. These schemes are shown to bring considerable gains over equal power allocation for practical antenna configurations (e.g., up to a few hundred). However, with fixed number of users (N), these gains diminish as M turns to infinity, and equal power allocation becomes optimal. A different conclusion is drawn for the case where both M and N grow large together, in which case: (i) improved rates are achieved as M grows with fixed M/N ratio, and (ii) the relative gains over the equal power allocation diminish as M/N grows. Moreover, we also provide applicable values of M/N under an acceptable power allocation gain threshold, which can be used as to determine when the proposed power allocation schemes yield appreciable gains, and when they do not. From the network point of view, the proposed scheduling approach can achieve almost the same performance as the joint power allocation after one scheduling round, with much reduced complexity.

Connected through hyperedge HE-1 (induced by source paper "on the pilot contamination attack in multi cell multiuser massive mimo networks"):
  with members:
    - "pilot spoofing attack by multiple eavesdroppers"
    - "multiple antennas secure transmission under pilot spoofing and jamming attack"
    - "active attack on user load achieving pilot design in massive mimo networks"
    - "user load analysis and pilot sequence design for multi cell massive mimo networks"
    - "the world s first real time testbed for massive mimo design implementation and validation"
    - "multi cell multiuser massive mimo networks user capacity analysis and pilot design"
    - "massive mimo pilot retransmission strategies for robustification against jamming"
    - "subverting massive mimo by smart jamming"

Connected through hyperedge HE-2 (induced by source paper "spectral efficiency analysis of cell free massive mimo systems with zero forcing detector"):
  with members:
    - "downlink precoding with mixed statistical and imperfect instantaneous csi for massive mimo systems"
    - "enhanced max min sinr for uplink cell free massive mimo systems"
    - "on the total energy efficiency of cell free massive mimo"
    - "performance analysis for massive mimo downlink with low complexity approximate zero forcing precoding"
    - "pilot power allocation through user grouping in multi cell massive mimo systems"
    - "energy efficient downlink transmission for multicell massive das with pilot contamination"
    - "energy efficiency in cell free massive mimo with zero forcing precoding design"
    - "cell free massive mimo versus small cells"

Connected through hyperedge HE-3 (induced by source paper "downlink pilot precoding and compressed channel feedback for fdd based cell free systems"):
  with members:
    - "channel feedback based on aod adaptive subspace codebook in fdd massive mimo systems"
    - "on the total energy efficiency of cell free massive mimo"
    - "joint channel training and feedback for fdd massive mimo systems"
    - "cell free massive mimo versus small cells"
    - "antenna grouping based feedback compression for fdd based massive mimo systems"
    - "downlink training techniques for fdd massive mimo systems open loop and closed loop training with memory"
    - "pilot contamination and precoding in multi cell tdd systems"
    - "mimo broadcast channels with finite rate feedback"

Connected through hyperedge HE-4 (induced by source paper "joint unicast and multi group multicast transmission in massive mimo systems"):
  with members:
    - "large system analysis of power normalization techniques in massive mimo"
    - "hybrid precoding for multi group physical layer multicasting"
    - "max min fair transmit precoding for multi group multicasting in massive mimo"
    - "multigroup multicast precoding in massive mimo"
    - "reducing the computational complexity of multicasting in large scale antenna systems"
    - "joint beamforming and broadcasting in massive mimo"
    - "hybrid precoding for physical layer multicasting"
    - "on the spectral efficiency and security enhancements of noma assisted multicast unicast streaming"

Connected through hyperedge HE-5 (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"
    - "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"
    - "downlink cellular network analysis with multi slope path loss models"

Connected through hyperedge HE-6 (induced by source paper "large system analysis of power normalization techniques in massive mimo"):
  with members:
    - "massive mimo has unlimited capacity"
    - "reducing the computational complexity of multicasting in large scale antenna systems"
    - "energy efficient downlink transmission for multicell massive das with pilot contamination"
    - "joint power allocation and user association optimization for massive mimo systems"
    - "convergence analysis and assurance for gaussian message passing iterative detector in massive mu mimo systems"
    - "pilot contamination is not a fundamental asymptotic limitation in massive mimo"
    - "massive mimo ten myths and one critical question"
    - "performance analysis of massive mimo for cell boundary users"

Connected through hyperedge HE-7 (induced by source paper "pilot power allocation through user grouping in multi cell massive mimo systems"):
  with members:
    - "channel estimation in massive mimo systems"
    - "uplink pilot and data power control for single cell massive mimo systems with mrc"
    - "massive mimo with non ideal arbitrary arrays hardware scaling laws and circuit aware design"
    - "multipair full duplex relaying with massive arrays and linear processing"
    - "power scaling of uplink massive mimo systems with arbitrary rank channel means"
    - "dealing with interference in distributed large scale mimo systems a statistical approach"
    - "massive mimo multicasting in noncooperative cellular networks"
    - "massive mimo systems with non ideal hardware energy efficiency estimation and capacity limits"

Connected through hyperedge HE-8 (induced by source paper "max min multicell aware precoding and power allocation for downlink massive mimo systems"):
  with members:
    - "large system analysis of base station cooperation for power minimization"
    - "optimal multiuser transmit beamforming a difficult problem with a simple solution structure"
    - "massive mimo for maximal spectral efficiency how many users and pilots should be allocated"
    - "joint beamforming and power control in coordinated multicell max min duality effective network and large system transition"
    - "large system analysis of linear precoding in correlated miso broadcast channels under limited feedback"
    - "base station cooperation on the downlink large system analysis"
    - "pilot contamination and precoding in multi cell tdd systems"

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)