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: "random access in uplink massive mimo systems how to exploit asynchronicity and excess antennas"
  Abstract: Massive MIMO systems, where the base stations are equipped with hundreds of antennas, are an attractive way to handle the rapid growth of data traffic. As the number of users increases, the initial access and handover in contemporary networks will be flooded by user collisions. In this work, we propose a random access procedure that resolves collisions and also performs timing, channel, and power estimation by simply utilizing the large number of antennas envisioned in massive MIMO systems and the inherent timing misalignments of uplink signals during network access and handover. Numerical results are used to validate the performance of the proposed solution under different settings. It turns out that the proposed solution can detect all collisions with a probability higher than 90%, at the same time providing reliable timing and channel estimates. Moreover, numerical results demonstrate that it is robust to overloaded situations.

Connected through hyperedge HE-1 (induced by source paper "timing advance estimation and beamforming of random access response in crowded tdd massive mimo systems"):
  with members:
    - "a random access protocol for pilot allocation in crowded massive mimo systems"
    - "random access protocol for massive mimo strongest user collision resolution sucr"
    - "what will 5g be"
    - "five disruptive technology directions for 5g"
    - "scaling up mimo opportunities and challenges with very large arrays"
    - "energy and spectral efficiency of very large multiuser mimo systems"

Connected through hyperedge HE-2 (induced by source paper "a random access protocol for pilot allocation in crowded massive mimo systems"):
  with members:
    - "massive mimo ten myths and one critical question"
    - "random access for massive mimo systems with intra cell pilot contamination"
    - "random access protocol for massive mimo strongest user collision resolution sucr"
    - "massive mimo for crowd scenarios a solution based on random access"
    - "three practical aspects of massive mimo intermittent user activity pilot synchronism and asymmetric deployment"
    - "coded random access applying codes on graphs to design random access protocols"
    - "massive mimo systems with non ideal hardware energy efficiency estimation and capacity limits"
    - "coded random access how coding theory helps to build random access protocols"

Connected through hyperedge HE-3 (induced by source paper "random pilot and data access in massive mimo for machine type communications"):
  with members:
    - "a random access protocol for pilot allocation in crowded massive mimo systems"
    - "coded pilot access a random access solution for massive mimo systems"
    - "massive mimo ten myths and one critical question"
    - "random access for massive mimo systems with intra cell pilot contamination"
    - "towards very large aperture massive mimo a measurement based study"
    - "random access protocol for massive mimo strongest user collision resolution sucr"
    - "massive mimo for crowd scenarios a solution based on random access"
    - "three practical aspects of massive mimo intermittent user activity pilot synchronism and asymmetric deployment"

Connected through hyperedge HE-4 (induced by source paper "random access protocols for massive mimo"):
  with members:
    - "a random access protocol for pilot allocation in crowded massive mimo systems"
    - "rrh based massive mimo with on the fly pilot contamination control"
    - "coded pilot access a random access solution for massive mimo systems"
    - "random access for massive mimo systems with intra cell pilot contamination"
    - "random access protocol for massive mimo strongest user collision resolution sucr"
    - "coded random access applying codes on graphs to design random access protocols"
    - "coded random access how coding theory helps to build random access protocols"
    - "massive mimo for next generation wireless 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)