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: "coded pilot access a random access solution for massive mimo systems"
  Abstract: We present a novel access protocol for crowd scenarios in massive MIMO (Multiple-input multiple-output) systems. Crowd scenarios are characterized by a large number of users with intermittent access behavior, whereby orthogonal scheduling is infeasible. In such scenarios, random access is a natural choice. The proposed access protocol relies on two essential properties of a massive MIMO system, namely asymptotic orthogonality between user channels and asymptotic invariance of channel powers. Signal processing techniques that take advantage of these properties allow us to view a set of contaminated pilot signals as a graph code on which iterative belief propagation can be performed. This makes it possible to decontaminate pilot signals and increase the throughput of the system. Numerical evaluations show that the proposed access protocol increases the throughput with 36%, when having 400 antennas at the base station, compared to the conventional method of slotted ALOHA. With 1024 antennas, the throughput is increased by 85%.

Connected through hyperedge HE-1 (induced by source paper "towards massive connectivity support for scalable mmtc communications in 5g networks"):
  with members:
    - "a random access protocol for pilot allocation in crowded massive mimo systems"
    - "compressive coded random access for massive mtc traffic in 5g systems"
    - "reliable and efficient access for alarm initiated and regular m2m traffic in ieee 802 11ah systems"
    - "massive machine type communication mmtc access with integrated authentication"
    - "reliable recovery of hierarchically sparse signals and application in machine type communications"
    - "pulse shaped ofdm for 5g systems"
    - "random access for massive mimo systems with intra cell pilot contamination"
    - "compressive random access using a common overloaded control channel"

Connected through hyperedge HE-2 (induced by source paper "virtual carrier sensing based random access in massive mimo systems"):
  with members:
    - "massive multiple access based on superposition raptor codes for cellular m2m communications"
    - "random access protocol for massive mimo strongest user collision resolution sucr"
    - "massive mimo for next generation wireless systems"
    - "what will 5g be"
    - "emerging technologies and research challenges for 5g wireless networks"
    - "five disruptive technology directions for 5g"

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"
    - "random access in uplink massive mimo systems how to exploit asynchronicity and excess antennas"
    - "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"
    - "random access in uplink massive mimo systems how to exploit asynchronicity and excess antennas"
    - "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)