human: Given a hyperedge-centered hypergraph: <hypergraph>, where the center hyperedge is induced by one source paper and its member nodes are the cited papers.

Details of the hypergraph:
Center hyperedge (induced by source paper "location aided pilot decontamination for massive mimo systems"):
  Abstract: One of the key limitation of massive MIMO systems is pilot contamination, which is defined as the interference during uplink channel estimation due to re-use of the same pilots in surrounding cells. In this paper, we propose a location-based approach to the pilot contamination problem for uplink MIMO systems. Our approach makes use of the approximate locations of mobile devices to provide good estimates of the channel statistics between the mobile devices and their corresponding base stations (BSs). We aim at minimizing the pilot contamination even when the number of BS antennas is not very large, and when multiple users from different cells, or even the same cell, are assigned the same pilot sequence. First, we characterize a desired angular region of the target user at the target BS in which interference is very low or zero, based on the number of BS antennas and the location of the target user. Second, based on this observation, we propose various pilot coordination methods for multi-user multi-cell scenarios to eliminate pilot contamination.

Includes members:
  Member "massive mimo has unlimited capacity":
    also connected through other hyperedges:
      - Hyperedge HE-1 (induced by source paper "joint power control and lsfd for wireless powered cell free massive mimo")
  Member "adaptive pilot clustering in heterogeneous massive mimo networks":
    also connected through other hyperedges:
      - Hyperedge HE-2 (induced by source paper "symbol level and multicast precoding for multiuser multiantenna downlink a survey classification and challenges")
  Member "low rank covariance assisted downlink training and channel estimation for fdd massive mimo systems":
    also connected through other hyperedges:
      - Hyperedge HE-3 (induced by source paper "fdd massive mimo via ul dl channel covariance extrapolation and active channel sparsification")
  Member "mitigating pilot contamination through location aware pilot assignment in massive mimo networks":
    also connected through other hyperedges:
      - Hyperedge HE-4 (induced by source paper "location aided pilot contamination avoidance for massive mimo systems")
  Member "performance analysis of massive mimo for cell boundary users":
    also connected through other hyperedges:
      - Hyperedge HE-5 (induced by source paper "a retrodirective wireless power transfer scheme for ambient backscatter systems")
  Member "spatially common sparsity based adaptive channel estimation and feedback for fdd massive mimo":
    also connected through other hyperedges:
      - Hyperedge HE-6 (induced by source paper "deep learning based fdd non stationary massive mimo downlink channel reconstruction")
  Member "pilot reuse for massive mimo transmission over spatially correlated rayleigh fading channels":
    also connected through other hyperedges:
      - Hyperedge HE-7 (induced by source paper "energy efficiency optimization for downlink massive mimo with statistical csit")
  Member "smart pilot assignment for massive mimo":
    also connected through other hyperedges:
      - Hyperedge HE-8 (induced by source paper "on the pilot contamination attack in multi cell multiuser massive mimo networks")

Question: Please tell me which class the source paper 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)