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: "performance of spatial modulation using measured real world channels"
  Abstract: In this paper, for the first time real--world channel measurements are used to analyse the performance of spatial modulation (SM), where a full analysis of the average bit error rate performance (ABER) of SM using measured urban correlated and uncorrelated Rayleigh fading channels is provided. The channel measurements are taken from an outdoor urban multiple input multiple output (MIMO) measurement campaign. Moreover, ABER performance results using simulated Rayleigh fading channels are provided and compared with a derived analytical bound for the ABER of SM, and the ABER results for SM using the measured urban channels. The ABER results using the measured urban channels validate the derived analytical bound and the ABER results using the simulated channels. Finally, the ABER of SM is compared with the performance of spatial multiplexing (SMX) using the measured urban channels for small and large scale MIMO. It is shown that SM offers nearly the same or a slightly better performance than SMX for small scale MIMO. However, SM offers large reduction in ABER for large scale MIMO.

Connected through hyperedge HE-1 (induced by source paper "a survey on spatial modulation in emerging wireless systems research progresses and applications"):
  with members:
    - "spatial modulation assisted multi antenna non orthogonal multiple access"
    - "adaptive spatial modulation based visible light communications ser analysis and optimization"
    - "two high performance schemes of transmit antenna selection for secure spatial modulation"
    - "receive spatial modulation for massive mimo systems"
    - "polarization shift keying polarsk system scheme and performance analysis"
    - "space time channel modulation"
    - "on the achievable spectral efficiency of spatial modulation aided downlink non orthogonal multiple access"
    - "spectral efficient analog precoding for generalized spatial modulation aided mmwave mimo"

Connected through hyperedge HE-2 (induced by source paper "space time block coded spatial modulation aided mmwave mimo with hybrid precoding"):
  with members:
    - "millimeter wave cellular wireless networks potentials and challenges"
    - "spatially sparse precoding in millimeter wave mimo systems"
    - "millimeter wave beamforming for wireless backhaul and access in small cell networks"

Connected through hyperedge HE-3 (induced by source paper "polarization shift keying polarsk system scheme and performance analysis"):
  with members:
    - "practical implementation of spatial modulation"
    - "space shift keying ssk mimo with practical channel estimates"

Connected through hyperedge HE-4 (induced by source paper "generalized spatial modulation in large scale multiuser mimo systems"):
  with members:
    - "massive mimo for next generation wireless systems"
    - "channel hardening exploiting message passing chemp receiver in large scale mimo systems"
    - "massive mimo systems signal processing challenges and research trends"
    - "scaling up mimo opportunities and challenges with very large arrays"
    - "practical implementation of spatial modulation"
    - "generalised sphere decoding for spatial modulation"

Connected through hyperedge HE-5 (induced by source paper "generalised sphere decoding for spatial modulation"):
  with members:
    - "practical implementation of spatial modulation"
    - "sphere decoding for spatial modulation systems with arbitrary nt"
    - "space shift keying ssk mimo with practical channel estimates"
    - "low complexity maximum likelihood detection in spatial modulation systems"
    - "massive mimo how many antennas do we need"
    - "high rate space time coded large mimo systems low complexity detection and channel estimation"

Connected through hyperedge HE-6 (induced by source paper "practical implementation of spatial modulation"):
  with members:
    - "generalised sphere decoding for spatial modulation"
    - "space shift keying ssk mimo with practical channel estimates"

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)