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: "exploiting network cooperation in green wireless communication"
  Abstract: There is a growing interest in energy efficient or so-called "green" wireless communication to reduce the energy consumption in cellular networks. Since today's wireless terminals are typically equipped with multiple network access interfaces such as Bluetooth, Wi-Fi, and cellular networks, this paper investigates user terminals cooperating with each other in transmitting their data packets to the base station (BS), by exploiting the multiple network access interfaces, called inter-network cooperation. We also examine the conventional schemes without user cooperation and with intra-network cooperation for comparison. Given target outage probability and data rate requirements, we analyze the energy consumption of conventional schemes as compared to the proposed inter-network cooperation by taking into account both physical-layer channel impairments (including path loss, fading, and thermal noise) and upper-layer protocol overheads. It is shown that distances between different network entities (i.e., user terminals and BS) have a significant influence on the energy efficiency of proposed inter-network cooperation scheme. Specifically, when the cooperating users are close to BS or the users are far away from each other, the inter-network cooperation may consume more energy than conventional schemes without user cooperation or with intra-network cooperation. However, as the cooperating users move away from BS and the inter-user distance is not too large, the inter-network cooperation significantly reduces the energy consumption over conventional schemes.

Connected through hyperedge HE-1 (induced by source paper "joint power splitting and relay selection in energy harvesting communications for iot networks"):
  with members:
    - "when internet of things meets blockchain challenges in distributed consensus"
    - "cooperative ambient backscatter communications for green internet of things"
    - "optimization of a power splitting protocol for two way multiple energy harvesting relay system"
    - "incentive mechanism design for wireless energy harvesting based internet of things"
    - "practical non linear energy harvesting model and resource allocation for swipt systems"
    - "optimal cooperative power allocation for energy harvesting enabled relay networks"
    - "outage probability of energy harvesting relay aided cooperative networks over rayleigh fading channel"
    - "power allocation strategies in energy harvesting wireless cooperative networks"

Connected through hyperedge HE-2 (induced by source paper "energy efficient mechanism for smart communication in cellular networks"):
  with members:
    - "downlink performance of cellular systems with base station sleeping user association and scheduling"
    - "massive mimo for next generation wireless systems"
    - "what will 5g be"
    - "five disruptive technology directions for 5g"
    - "transmission capacity of wireless networks"
    - "energy and spectral efficiency of very large multiuser mimo systems"
    - "a survey of green networking research"

Connected through hyperedge HE-3 (induced by source paper "on secrecy performance of antenna selection aided mimo systems against eavesdropping"):
  with members:
    - "improving physical layer security in wireless communications using diversity techniques"
    - "secrecy outage and diversity analysis of cognitive radio systems"
    - "optimal relay selection for physical layer security in cooperative wireless networks"
    - "physical layer security with multiuser scheduling in cognitive radio networks"
    - "the secrecy capacity of the mimo wiretap channel"

Connected through hyperedge HE-4 (induced by source paper "cognitive network cooperation for green cellular networks"):
  with members:
    - "cellular base station assisted device to device communications in tv white space"
    - "securing physical layer communications for cognitive radio networks"

Connected through hyperedge HE-5 (induced by source paper "5g green cellular networks considering power allocation schemes"):
  with members:
    - "quantifying potential energy efficiency gain in green cellular wireless networks"
    - "throughput and energy efficiency analysis of small cell networks with multi antenna base stations"
    - "energy efficiency evaluation of cellular networks based on spatial distributions of traffic load and power consumption"
    - "energy efficiency optimization for mimo broadcast channels"
    - "capacity analysis of a multi cell multi antenna cooperative cellular network with co channel interference"
    - "green cellular networks a survey some research issues and challenges"

Connected through hyperedge HE-6 (induced by source paper "quantifying potential energy efficiency gain in green cellular wireless networks"):
  with members:
    - "predictive green wireless access exploiting mobility and application information"
    - "green cellular networks a survey some research issues and challenges"
    - "beamsteering on mobile devices network capacity and client efficiency"
    - "a survey of green networking research"
    - "femtocell networks a survey"

Connected through hyperedge HE-7 (induced by source paper "optimal pricing and load sharing for energy saving in communications cooperation"):
  with members:
    - "joint transmitter and receiver energy minimization in multiuser ofdm 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)