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: "low complexity maximum likelihood detection in spatial modulation systems"
  Abstract: Spatial Modulation (SM) is a recently developed low-complexity Multiple-Input Multiple-Output scheme that uses antenna indices and a conventional signal set to convey information. It has been shown that the Maximum-Likelihood (ML) detection in an SM system involves joint detection of the transmit antenna index and the transmitted symbol, and hence, the ML search complexity grows linearly with the number of transmit antennas and the size of the signal set. In this paper, we show that the ML search complexity in an SM system becomes independent of the constellation size when the signal set employed is a square- or a rectangular-QAM. Further, we show that Sphere Decoding (SD) algorithms become essential in SM systems only when the number of transmit antennas is large and not necessarily when the employed signal set is large. We propose a novel {\em hard-limiting} enabled sphere decoding detector whose complexity is lesser than that of the existing detector and a generalized detection scheme for SM systems with {\em arbitrary} number of transmit antennas. We support our claims with simulation results that the proposed detectors are ML-optimal and offer a significantly reduced complexity.

Connected through hyperedge HE-1 (induced by source paper "generalised sphere decoding for spatial modulation"):
  with members:
    - "performance of spatial modulation using measured real world channels"
    - "practical implementation of spatial modulation"
    - "sphere decoding for spatial modulation systems with arbitrary nt"
    - "space shift keying ssk mimo with practical channel estimates"
    - "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-2 (induced by source paper "spatial modulation in zero padded single carrier communication"):
  with members:
    - "on full diversity space time block codes with partial interference cancellation group decoding"

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)