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: "adaptive pilot clustering in heterogeneous massive mimo networks"
  Abstract: We consider the uplink of a cellular massive multiple-input multiple-output network. Acquiring channel state information at the base stations (BSs) requires uplink pilot signaling. Since the number of orthogonal pilot sequences is limited by the channel coherence, pilot reuse across cells is necessary to achieve high spectral efficiency. However, finding efficient pilot reuse patterns is non-trivial, especially in practical asymmetric BS deployments. We approach this problem using the coalitional game theory. Each BS has a few unique pilots and can form coalitions with other BSs to gain access to more pilots. The BSs in a coalition, thus, benefit from serving more users in their cells at the expense of higher pilot contamination and interference. Given that a cell’s average spectral efficiency depends on the overall pilot reuse pattern, the suitable coalitional game model is in the partition form. We develop a low-complexity distributed coalition formation based on individual stability. By incorporating a BS intercommunication budget constraint, we are able to control the overhead in message exchange between the BSs and ensure the algorithm’s convergence to a solution of the game called individually stable coalition structure. Simulation results reveal fast algorithmic convergence and substantial performance gains over the baseline schemes with no pilot reuse, full pilot reuse, or random pilot reuse pattern.

Connected through hyperedge HE-1 (induced by source paper "symbol level and multicast precoding for multiuser multiantenna downlink a survey classification and challenges"):
  with members:
    - "channel estimation and performance analysis of one bit massive mimo systems"
    - "an overview on resource allocation techniques for multi user mimo systems"
    - "spatio temporal waveform design for multiuser massive mimo downlink with 1 bit receivers"
    - "joint beamforming and broadcasting in massive mimo"
    - "coordinate update algorithms for robust power loading for the mu miso downlink with outage constraints"
    - "energy efficient symbol level precoding in multiuser miso based on relaxed detection region"
    - "robust transmission in downlink multiuser miso systems a rate splitting approach"
    - "a rate splitting strategy for max min fair multigroup multicasting"

Connected through hyperedge HE-2 (induced by source paper "distributed long term base station clustering in cellular networks using coalition formation"):
  with members:
    - "globally optimal base station clustering in interference alignment based multicell networks"
    - "cooperative base station coloring for pair wise multi cell coordination"
    - "overhead aware distributed csi selection in the mimo interference channel"
    - "interference alignment aided base station clustering using coalition formation"
    - "what will 5g be"
    - "on the feasibility of linear interference alignment for mimo interference broadcast channels with constant coefficients"
    - "coalitional games in partition form for joint spectrum sensing and access in cognitive radio networks"
    - "fundamental limits of cooperation"

Connected through hyperedge HE-3 (induced by source paper "location aided pilot decontamination for massive mimo systems"):
  with members:
    - "massive mimo has unlimited capacity"
    - "low rank covariance assisted downlink training and channel estimation for fdd massive mimo systems"
    - "mitigating pilot contamination through location aware pilot assignment in massive mimo networks"
    - "performance analysis of massive mimo for cell boundary users"
    - "spatially common sparsity based adaptive channel estimation and feedback for fdd massive mimo"
    - "pilot reuse for massive mimo transmission over spatially correlated rayleigh fading channels"
    - "smart pilot assignment for massive mimo"
    - "massive mimo for next generation wireless systems"

Connected through hyperedge HE-4 (induced by source paper "globally optimal base station clustering in interference alignment based multicell networks"):
  with members:
    - "distributed long term base station clustering in cellular networks using coalition formation"
    - "on the feasibility of linear interference alignment for mimo interference broadcast channels with constant coefficients"
    - "user partitioning for less overhead in mimo interference channels"
    - "interference alignment with analog channel state feedback"
    - "interference alignment with limited feedback"
    - "pilot contamination and precoding in multi cell tdd systems"

Connected through hyperedge HE-5 (induced by source paper "graph coloring based pilot allocation to mitigate pilot contamination for multi cell massive mimo systems"):
  with members:
    - "pilot clustering in asymmetric massive mimo networks"
    - "blind pilot decontamination"
    - "a coordinated approach to channel estimation in large scale multiple antenna 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)