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: "energy efficient transmission design in non orthogonal multiple access"
  Abstract: Non-orthogonal multiple access (NOMA) is considered as a promising technology for improving the spectral efficiency (SE) in 5G. In this correspondence, we study the benefit of NOMA in enhancing energy efficiency (EE) for a multi-user downlink transmission, where the EE is defined as the ratio of the achievable sum rate of the users to the total power consumption. Our goal is to maximize the EE subject to a minimum required data rate for each user, which leads to a non-convex fractional programming problem. To solve it, we first establish the feasible range of the transmitting power that is able to support each user's data rate requirement. Then, we propose an EE-optimal power allocation strategy that maximizes the EE. Our numerical results show that NOMA has superior EE performance in comparison with conventional orthogonal multiple access (OMA).

Connected through hyperedge HE-1 (induced by source paper "a survey of rate optimal power domain noma schemes for enabling technologies of future wireless networks"):
  with members:
    - "generalized coordinated multipoint gcomp enabled noma outage capacity and power allocation"
    - "what role can noma play in massive mimo"
    - "uav data collection over noma backscatter networks uav altitude and trajectory optimization"
    - "uav communications for 5g and beyond recent advances and future trends"
    - "when full duplex wireless meets non orthogonal multiple access opportunities and challenges"
    - "on optimizing vlc networks for downlink multi user transmission a survey"
    - "beam design and user scheduling for nonorthogonal multiple access with multiple antennas based on pareto optimality"
    - "spatial modulation assisted multi antenna non orthogonal multiple access"

Connected through hyperedge HE-2 (induced by source paper "downlink analysis of noma enabled cellular networks with 3gpp inspired user ranking"):
  with members:
    - "downlink analysis for the typical cell in poisson cellular networks"
    - "noma in the uplink delay analysis with imperfect csi and finite length coding"
    - "meta distribution of downlink non orthogonal multiple access noma in poisson networks"
    - "downlink non orthogonal multiple access noma in poisson networks"
    - "stochastic geometry based uplink analysis of massive mimo systems with fractional pilot reuse"
    - "accuracy of distance based ranking of users in the analysis of noma systems"
    - "non orthogonal multiple access in large scale heterogeneous networks"
    - "a survey on non orthogonal multiple access for 5g networks research challenges and future trends"

Connected through hyperedge HE-3 (induced by source paper "energy efficient joint user rb association and power allocation for uplink hybrid noma oma"):
  with members:
    - "energy efficient power allocation in uplink mmwave massive mimo with noma"
    - "energy efficient noma enabled heterogeneous cloud radio access networks"
    - "power domain non orthogonal multiple access noma in 5g systems potentials and challenges"
    - "energy efficient power allocation in millimeter wave massive mimo with non orthogonal multiple access"
    - "resource allocation for downlink noma systems key techniques and open issues"
    - "joint power control and beamforming for uplink non orthogonal multiple access in 5g millimeter wave communications"
    - "noma in 5g systems exciting possibilities for enhancing spectral efficiency"
    - "a fair individual rate comparison between mimo noma and mimo oma"

Connected through hyperedge HE-4 (induced by source paper "secure users oriented downlink miso noma"):
  with members:
    - "exploiting inter user interference for secure massive non orthogonal multiple access"
    - "secure communications in noma system subcarrier assignment and power allocation"
    - "secrecy sum rate maximization in non orthogonal multiple access"
    - "relay selection for cooperative noma"
    - "on the spectral efficiency and security enhancements of noma assisted multicast unicast streaming"
    - "optimal joint power and subcarrier allocation for full duplex multicarrier non orthogonal multiple access systems"
    - "on the design of secure non orthogonal multiple access systems"
    - "physical layer security in millimeter wave cellular networks"

Connected through hyperedge HE-5 (induced by source paper "online power allocation at energy harvesting transmitter for multiple receivers with and without individual rate constraints for oma and noma transmissions"):
  with members:
    - "stochastic control of computation offloading to a helper with a dynamically loaded cpu"
    - "dynamic computation offloading for mobile edge computing with energy harvesting devices"
    - "online power control optimization for wireless transmission with energy harvesting and storage"
    - "energy efficient resource allocation in ofdma systems with hybrid energy harvesting base station"
    - "throughput optimal policies for energy harvesting wireless transmitters with non ideal circuit power"
    - "optimal energy allocation for wireless communications with energy harvesting constraints"

Connected through hyperedge HE-6 (induced by source paper "reconsidering design of multi antenna noma systems with limited feedback"):
  with members:
    - "exploiting multiple antenna techniques for non orthogonal multiple access"
    - "design of massive mimo noma with limited feedback"
    - "fairness for non orthogonal multiple access in 5g systems"
    - "on the performance of non orthogonal multiple access in 5g systems with randomly deployed users"
    - "mimo broadcast channels with finite rate feedback"

Connected through hyperedge HE-7 (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-8 (induced by source paper "multi beam noma for hybrid mmwave systems"):
  with members:
    - "on low resolution adcs in practical 5g millimeter wave massive mimo systems"
    - "a multi beam noma framework for hybrid mmwave systems"
    - "rate splitting multiple access for downlink communication systems bridging generalizing and outperforming sdma and noma"
    - "optimal resource allocation for power efficient mc noma with imperfect channel state information"
    - "optimal user scheduling and power allocation for millimeter wave noma systems"
    - "millimeter wave communication with non orthogonal multiple access for 5g"
    - "spectrum and energy efficient beamspace mimo noma for millimeter wave communications using lens antenna array"
    - "multi user precoding and channel estimation for hybrid millimeter wave systems"

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)