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: "quasi cyclic ldpc codes based on pre lifted protographs"
  Abstract: Quasi-cyclic low-density parity-check (QC-LDPC) codes based on protographs are of great interest to code designers because analysis and implementation are facilitated by the protograph structure and the use of circulant permutation matrices for protograph lifting. However, these restrictions impose undesirable fixed upper limits on important code parameters, such as minimum distance and girth. In this paper, we consider an approach to constructing QC-LDPC codes that uses a two-step lifting procedure based on a protograph, and, by following this method instead of the usual one-step procedure, we obtain improved minimum distance and girth properties. We also present two new design rules for constructing good QC-LDPC codes using this two-step lifting procedure, and in each case we obtain a significant increase in minimum distance and achieve a certain guaranteed girth compared to one-step circulant-based liftings. The expected performance improvement is verified by simulation results.

Connected through hyperedge HE-1 (induced by source paper "outage limit approaching protograph ldpc codes for slow fading wireless communications"):
  with members:
    - "improving the decoding threshold of tailbiting spatially coupled ldpc codes by energy shaping"
    - "on the tanner graph cycle distribution of random ldpc random protograph based ldpc and random quasi cyclic ldpc code ensembles"
    - "construction of near capacity protograph ldpc code sequences with block error thresholds"
    - "low density graph codes for coded cooperation on slow fading relay channels"

Connected through hyperedge HE-2 (induced by source paper "a new multi edge metric constrained peg algorithm for designing binary ldpc code with improved cycle structure"):
  with members:
    - "design of multiple edge protographs for qc ldpc codes avoiding short inevitable cycles"
    - "searching for voltage graph based ldpc tailbiting codes with large girth"
    - "design of finite length irregular protograph codes with low error floors over the binary input awgn channel using cyclic liftings"

Connected through hyperedge HE-3 (induced by source paper "hierarchical and high girth qc ldpc codes"):
  with members:
    - "quasi cyclic ldpc codes influence of proto and tanner graph structure on minimum hamming distance upper bounds"
    - "searching for voltage graph based ldpc tailbiting codes with large girth"
    - "threshold saturation via spatial coupling why convolutional ldpc ensembles perform so well over the bec"
    - "lowering the error floor of ldpc codes using cyclic liftings"
    - "shortened array codes of large girth"

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)