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: "massive mimo for maximal spectral efficiency how many users and pilots should be allocated"
  Abstract: Massive MIMO is a promising technique to increase the spectral efficiency (SE) of cellular networks, by deploying antenna arrays with hundreds or thousands of active elements at the base stations and performing coherent transceiver processing. A common rule-of-thumb is that these systems should have an order of magnitude more antennas, $M$, than scheduled users, $K$, because the users' channels are likely to be near-orthogonal when $M/K > 10$. However, it has not been proved that this rule-of-thumb actually maximizes the SE. In this paper, we analyze how the optimal number of scheduled users, $K^\star$, depends on $M$ and other system parameters. To this end, new SE expressions are derived to enable efficient system-level analysis with power control, arbitrary pilot reuse, and random user locations. The value of $K^\star$ in the large-$M$ regime is derived in closed form, while simulations are used to show what happens at finite $M$, in different interference scenarios, with different pilot reuse factors, and for different processing schemes. Up to half the coherence block should be dedicated to pilots and the optimal $M/K$ is less than 10 in many cases of practical relevance. Interestingly, $K^\star$ depends strongly on the processing scheme and hence it is unfair to compare different schemes using the same $K$.

Connected through hyperedge HE-1 (induced by source paper "massive mimo for internet of things iot connectivity"):
  with members:
    - "massive mimo unsourced random access"
    - "ultrareliable and low latency communication techniques for tactile internet services"
    - "non stationarities in extra large scale massive mimo"
    - "ubiquitous cell free massive mimo communications"
    - "sparcs for unsourced random access"
    - "management of network slicing in 5g radio access networks functional framework and information models"
    - "grant free massive mtc enabled massive mimo a compressive sensing approach"
    - "massive mimo for ultra reliable communications with constellations for dual coherent noncoherent detection"

Connected through hyperedge HE-2 (induced by source paper "spectral efficiency of one bit sigma delta massive mimo"):
  with members:
    - "one bit sigma delta mimo precoding"
    - "a framework for one bit and constant envelope precoding over multiuser massive miso channels"
    - "quantized constant envelope precoding with psk and qam signaling"
    - "one bit precoding and constellation range design for massive mimo with qam signaling"
    - "one bit sphere decoding for uplink massive mimo systems with one bit adcs"
    - "1 bit massive mu mimo precoding in vlsi"
    - "throughput analysis of massive mimo uplink with low resolution adcs"
    - "channel estimation and performance analysis of one bit massive mimo systems"

Connected through hyperedge HE-3 (induced by source paper "scalable cell free massive mimo systems"):
  with members:
    - "a new look at cell free massive mimo making it practical with dynamic cooperation"
    - "scalability aspects of cell free massive mimo"
    - "making cell free massive mimo competitive with mmse processing and centralized implementation"
    - "covariance matrix estimation for massive mimo"
    - "massive mimo in sub 6 ghz and mmwave physical practical and use case differences"
    - "on the performance of backhaul constrained cell free massive mimo with linear receivers"
    - "fog massive mimo a user centric seamless hot spot architecture"
    - "covariance matrix estimation in massive mimo"

Connected through hyperedge HE-4 (induced by source paper "performance analysis of large intelligent surfaces liss uplink spectral efficiency and pilot training"):
  with members:
    - "a vision of 6g wireless systems applications trends technologies and open research problems"
    - "reliability analysis of large intelligent surfaces liss rate distribution and outage probability"
    - "towards smart and reconfigurable environment intelligent reflecting surface aided wireless network"
    - "beyond 5g with uavs foundations of a 3d wireless cellular network"
    - "energy efficient multi user miso communication using low resolution large intelligent surfaces"
    - "joint communication and control for wireless autonomous vehicular platoon systems"
    - "beyond massive mimo the potential of positioning with large intelligent surfaces"
    - "capacity degradation with modeling hardware impairment in large intelligent surface"

Connected through hyperedge HE-5 (induced by source paper "making cell free massive mimo competitive with mmse processing and centralized implementation"):
  with members:
    - "ubiquitous cell free massive mimo communications"
    - "large scale fading decoding in cellular massive mimo systems with spatially correlated channels"
    - "few bit csi acquisition for centralized cell free massive mimo with spatial correlation"
    - "can massive mimo support uplink intensive applications"
    - "on the performance of backhaul constrained cell free massive mimo with linear receivers"
    - "massive mimo has unlimited capacity"
    - "performance of cell free massive mimo systems with mmse and lsfd receivers"
    - "on the total energy efficiency of cell free massive mimo"

Connected through hyperedge HE-6 (induced by source paper "hardware distortion correlation has negligible impact on ul massive mimo spectral efficiency"):
  with members:
    - "massive mimo has unlimited capacity"
    - "can hardware distortion correlation be neglected when analyzing uplink se in massive mimo"
    - "out of band radiation from antenna arrays clarified"
    - "spatial characteristics of distortion radiated from antenna arrays with transceiver nonlinearities"
    - "performance characterization of a real time massive mimo system with los mobile channels"
    - "throughput analysis of massive mimo uplink with low resolution adcs"
    - "achievable uplink rates for massive mimo with coarse quantization"
    - "impact of spatial filtering on distortion from low noise amplifiers in massive mimo base stations"

Connected through hyperedge HE-7 (induced by source paper "on the spectral efficiency for massive mimo systems with imperfect spacial covariance information"):
  with members:
    - "covariance matrix estimation for massive mimo"
    - "covariance matrix estimation in massive mimo"
    - "massive mimo has unlimited capacity"
    - "superimposed pilots are superior for mitigating pilot contamination in massive mimo"
    - "massive mimo pilot decontamination and channel interpolation via wideband sparse channel estimation"
    - "massive mimo with imperfect channel covariance information"
    - "path loss shadow fading and line of sight probability models for 5g urban macro cellular scenarios"
    - "massive mimo for next generation wireless systems"

Connected through hyperedge HE-8 (induced by source paper "massive mimo forward link analysis for cellular networks"):
  with members:
    - "massive mimo has unlimited capacity"
    - "modeling and analysis of cellular networks using stochastic geometry a tutorial"
    - "the meta distribution of the sir for cellular networks with power control"
    - "ergodic spectral efficiency in mimo cellular networks"
    - "downlink performance of superimposed pilots in massive mimo systems"
    - "wireless network signals with moderately correlated shadowing still appear poisson"
    - "no downlink pilots are needed in tdd massive mimo"
    - "analyzing uplink sinr and rate in massive mimo systems using stochastic geometry"

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)