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 aware wireless relay selection in load coupled ofdma cellular networks"
  Abstract: We investigate transmission energy minimization via optimizing wireless relay selection in orthogonal-frequency-division multiple access (OFDMA) networks. We take into account the impact of the load of cells on transmission energy. We prove the NP-hardness of the energy-aware wireless relay selection problem. To tackle the computational complexity, a partial optimality condition is derived for providing insights in respect of designing an effective and efficient algorithm. Numerical results show that the resulting algorithm achieves high energy performance.

Connected through hyperedge HE-1 (induced by source paper "a note on decoding order in optimizing multi cell noma"):
  with members:
    - "a robust machine learning method for cell load approximation in wireless networks"
    - "a framework for optimizing multi cell noma delivering demand with less resource"
    - "resource optimization with load coupling in multi cell noma"
    - "on optimal power allocation for downlink non orthogonal multiple access systems"
    - "load optimization with user association in cooperative and load coupled lte networks"
    - "dynamic user clustering and power allocation for uplink and downlink non orthogonal multiple access noma systems"
    - "elementary properties of positive concave mappings with applications to network planning and optimization"
    - "power and channel allocation for non orthogonal multiple access in 5g systems tractability and computation"

Connected through hyperedge HE-2 (induced by source paper "resource optimization with load coupling in multi cell noma"):
  with members:
    - "a robust machine learning method for cell load approximation in wireless networks"
    - "a framework for optimizing multi cell noma delivering demand with less resource"
    - "on optimal power allocation for downlink non orthogonal multiple access systems"
    - "sub channel assignment power allocation and user scheduling for non orthogonal multiple access networks"
    - "load optimization with user association in cooperative and load coupled lte networks"
    - "elementary properties of positive concave mappings with applications to network planning and optimization"
    - "power and channel allocation for non orthogonal multiple access in 5g systems tractability and computation"
    - "energy efficiency of distributed signal processing in wireless networks a cross layer analysis"

Connected through hyperedge HE-3 (induced by source paper "wireless network level partial relay cooperation a stable throughput analysis"):
  with members:
    - "relay selection in cooperative power line communication a multi armed bandit approach"
    - "wireless energy harvesting in a cognitive relay network"
    - "probabilistic cooperation of a full duplex relay in random access networks"
    - "on the stability of random multiple access with stochastic energy harvesting"
    - "effect of energy harvesting on stable throughput in cooperative relay systems"
    - "relay assisted multiple access with full duplex multi packet reception"
    - "5g cellular key enabling technologies and research challenges"
    - "a buffer aided successive opportunistic relay selection scheme with power adaptation and inter relay interference cancellation for cooperative diversity systems"

Connected through hyperedge HE-4 (induced by source paper "resource optimization in multi cell noma"):
  with members:
    - "a framework for optimizing multi cell noma delivering demand with less resource"
    - "on optimal power allocation for downlink non orthogonal multiple access systems"
    - "load optimization with user association in cooperative and load coupled lte networks"
    - "elementary properties of positive concave mappings with applications to network planning and optimization"
    - "energy efficiency of distributed signal processing in wireless networks a cross layer analysis"
    - "non orthogonal multiple access in multi cell networks theory performance and practical challenges"
    - "power and load coupling in cellular networks for energy optimization"
    - "optimal cell clustering and activation for energy saving in load coupled wireless networks"

Connected through hyperedge HE-5 (induced by source paper "a framework for optimizing multi cell noma delivering demand with less resource"):
  with members:
    - "load optimization with user association in cooperative and load coupled lte networks"
    - "energy efficiency of distributed signal processing in wireless networks a cross layer analysis"
    - "non orthogonal multiple access in multi cell networks theory performance and practical challenges"
    - "optimal cell clustering and activation for energy saving in load coupled wireless networks"
    - "analysis of cell load coupling for lte network planning and optimization"

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)