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: "scma codebook design"
  Abstract: Multicarrier CDMA is a multiple access scheme in which modulated QAM symbols are spread over OFDMA tones by using a generally complex spreading sequence. Effectively, a QAM symbol is repeated over multiple tones. Low density signature (LDS) is a version of CDMA with low density spreading sequences allowing us to take advantage of a near optimal message passing algorithm (MPA) receiver with practically feasible complexity. Sparse code multiple access (SCMA) is a multi-dimensional codebook-based non-orthogonal spreading technique. In SCMA, the procedure of bit to QAM symbol mapping and spreading are combined together and incoming bits are directly mapped to multi-dimensional codewords of SCMA codebook sets. Each layer has its dedicated codebook. Shaping gain of a multi-dimensional constellation is one of the main sources of the performance improvement in comparison to the simple repetition of QAM symbols in LDS. Meanwhile, like LDS, SCMA enjoys the low complexity reception techniques due to the sparsity of SCMA codewords. In this paper a systematic approach is proposed to design SCMA codebooks mainly based on the design principles of lattice constellations. Simulation results are presented to show the performance gain of SCMA compared to LDS and OFDMA.

Connected through hyperedge HE-1 (induced by source paper "design of scma codebooks using differential evolution"):
  with members:
    - "multidimensional constellations for uplink scma systems a comparative study"

Connected through hyperedge HE-2 (induced by source paper "tcm noma joint multi user codeword design and detection in trellis coded modulation based noma for beyond 5g"):
  with members:
    - "a survey on non orthogonal multiple access for 5g networks research challenges and future trends"
    - "sub channel assignment power allocation and user scheduling for non orthogonal multiple access networks"
    - "dense point sets have sparse delaunay triangulations"

Connected through hyperedge HE-3 (induced by source paper "non orthogonal multiple access for 5g and beyond"):
  with members:
    - "downlink non orthogonal multiple access with limited feedback"
    - "optimal user scheduling and power allocation for millimeter wave noma systems"
    - "coordinated multi point comp transmission in downlink multi cell noma systems models and spectral efficiency performance"
    - "low complexity receiver for multi level polar coded modulation in non orthogonal multiple access"
    - "massive non orthogonal multiple access for cellular iot potentials and limitations"
    - "power domain non orthogonal multiple access noma in 5g systems potentials and challenges"
    - "modulation and multiple access for 5g networks"
    - "robust beamforming techniques for non orthogonal multiple access systems with bounded channel uncertainties"

Connected through hyperedge HE-4 (induced by source paper "multidimensional constellations for uplink scma systems a comparative study"):
  with members:
    - "survey on multi access edge computing for internet of things realization"
    - "low complexity receiver for uplink scma system via expectation propagation"
    - "a survey on non orthogonal multiple access for 5g networks research challenges and future trends"
    - "modulation and multiple access for 5g networks"
    - "an optimization perspective of the superiority of noma compared to conventional oma"
    - "polar codes for scma systems"
    - "a survey on low latency towards 5g ran core network and caching solutions"
    - "design of non orthogonal multiple access enhanced backscatter communication"

Connected through hyperedge HE-5 (induced by source paper "fairness and sum rate maximization via joint channel and power allocation in uplink scma networks"):
  with members:
    - "single or multiple frames content delivery for next generation networks"
    - "a survey on non orthogonal multiple access for 5g networks research challenges and future trends"
    - "fundamental limits of low density spreading noma with fading"
    - "modeling and analysis of scma enhanced d2d and cellular hybrid network"
    - "joint downlink base station association and power control for max min fairness computation and complexity"
    - "distributed pricing based user association for downlink heterogeneous cellular networks"
    - "scma for downlink multiple access of 5g wireless networks"
    - "uplink contention based scma for 5g radio access"

Connected through hyperedge HE-6 (induced by source paper "a survey on non orthogonal multiple access for 5g networks research challenges and future trends"):
  with members:
    - "exploiting multiple antenna techniques for non orthogonal multiple access"
    - "achievable rate region of non orthogonal multiple access systems with wireless powered decoder"
    - "a new view of multi user hybrid massive mimo non orthogonal angle division multiple access"
    - "on non orthogonal multiple access with finite alphabet inputs in z channels"
    - "spectrum and energy efficient beamspace mimo noma for millimeter wave communications using lens antenna array"
    - "practical power balanced non orthogonal multiple access"
    - "noma based random access with multichannel aloha"
    - "optimal power allocation scheme for non orthogonal multiple access with alpha fairness"

Connected through hyperedge HE-7 (induced by source paper "modulation and multiple access for 5g networks"):
  with members:
    - "power domain non orthogonal multiple access noma in 5g systems potentials and challenges"
    - "non orthogonal multiple access in large scale heterogeneous networks"
    - "capacity comparison between mimo noma and mimo oma with multiple users in a cluster"
    - "wireless powered communications with non orthogonal multiple access"
    - "nonorthogonal multiple access in large scale underlay cognitive radio networks"
    - "design of massive mimo noma with limited feedback"
    - "optimal joint power and subcarrier allocation for mc noma systems"
    - "relay selection for cooperative noma"

Connected through hyperedge HE-8 (induced by source paper "iterative receivers for downlink mimo scma message passing and distributed cooperative detection"):
  with members:
    - "wireless powered communications with non orthogonal multiple access"
    - "nonorthogonal multiple access in large scale underlay cognitive radio networks"
    - "a survey of downlink non orthogonal multiple access for 5g wireless communication networks"
    - "gaussian message passing iterative detection for mimo noma systems with massive access"
    - "fast admm algorithm for distributed optimization with adaptive penalty"
    - "what will 5g be"
    - "on the performance of non orthogonal multiple access in 5g systems with randomly deployed users"
    - "expectation propagation for approximate bayesian inference"

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)