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 "cfo estimation for massive mu mimo systems"):
  Abstract: Low-complexity carrier frequency offset (CFO) estimation/compensation in massive multi-user (MU) multiple-input multiple-output (MIMO) systems is a challenging problem. The existing CFO estimation/compensation strategies for conventional small MIMO systems experience tremendous increase in complexity with increasing number of the user terminals (UTs), $K$ and the number of base station (BS) antennas, $M$ (i.e. in massive MIMO regime). In this paper, we devise a \textit{low-complexity} algorithm for CFO estimation using the pilots received at the BS during a special uplink slot. The total per-channel use complexity of the proposed algorithm increases only linearly with increasing $M$ and is independent of $K$. Analytical expression is derived for the mean square error (MSE) of the proposed CFO estimator. Further analysis reveals that the MSE of the proposed estimator decreases with increasing $M$ (fixed $K$) and increasing $K$ (fixed $M$ and CFO pilot sequence length $\gg K$). We also derive an achievable information sum-rate expression of the time-reversal maximal-ratio-combining (TR-MRC) detector in the presence of residual CFO errors, resulting from the proposed CFO estimation/compensation algorithm. Analysis of this information rate expression reveals that an $\mathcal{O}(\sqrt{M})$ array gain is achievable. This new result is interesting since the best possible array gain under an ideal no CFO condition is also known to be $\mathcal{O}(\sqrt{M})$.

Includes members:
  Member "uplink performance of time reversal mrc in massive mimo systems subject to phase noise":
    also connected through other hyperedges:
      - Hyperedge HE-1 (induced by source paper "achieving phase coherency and gain stability in active antenna arrays for sub 6 ghz fdd and tdd fd mimo challenges and solutions")
  Member "massive mimo for next generation wireless systems":
    also connected through other hyperedges:
      - Hyperedge HE-2 (induced by source paper "joint power control and lsfd for wireless powered cell free massive mimo")
  Member "five disruptive technology directions for 5g":
    also connected through other hyperedges:
      - Hyperedge HE-3 (induced by source paper "deep learning enabled optimization of downlink beamforming under per antenna power constraints algorithms and experimental demonstration")
  Member "scaling up mimo opportunities and challenges with very large arrays":
    also connected through other hyperedges:
      - Hyperedge HE-4 (induced by source paper "downlink secrecy rate of one bit massive mimo system with active eavesdropping")
  Member "energy and spectral efficiency of very large multiuser mimo systems":
    also connected through other hyperedges:
      - Hyperedge HE-5 (induced by source paper "downlink secrecy rate of one bit massive mimo system with active eavesdropping")
  Member "blind estimation of multiple carrier frequency offsets":
    also connected through other hyperedges:
      - Hyperedge HE-6 (induced by source paper "impact of cfo estimation on the performance of zf receiver in massive mu mimo systems")

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)