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: "the impact of qos constraints on the energy efficiency of fixed rate wireless transmissions"
  Abstract: Transmission over wireless fading channels under quality of service (QoS) constraints is studied when only the receiver has channel side information. Being unaware of the channel conditions, transmitter is assumed to send the information at a fixed rate. Under these assumptions, a two-state (ON-OFF) transmission model is adopted, where information is transmitted reliably at a fixed rate in the ON state while no reliable transmission occurs in the OFF state. QoS limitations are imposed as constraints on buffer violation probabilities, and effective capacity formulation is used to identify the maximum throughput that a wireless channel can sustain while satisfying statistical QoS constraints. Energy efficiency is investigated by obtaining the bit energy required at zero spectral efficiency and the wideband slope in both wideband and low-power regimes assuming that the receiver has perfect channel side information (CSI). In both wideband and low-power regimes, the increased energy requirements due to the presence of QoS constraints are quantified. Comparisons with variable-rate/fixed-power and variable-rate/variable-power cases are given. Energy efficiency is further analyzed in the presence of channel uncertainties. The optimal fraction of power allocated to training is identified under QoS constraints. It is proven that the minimum bit energy in the low-power regime is attained at a certain nonzero power level below which bit energy increases without bound with vanishing power.

Connected through hyperedge HE-1 (induced by source paper "joint queue aware and channel aware delay optimal scheduling of arbitrarily bursty traffic over multi state time varying channels"):
  with members:
    - "on optimizing power allocation for reliable communication over fading channels with uninformed transmitter"
    - "optimum transmission rate in fading channels with markovian sources and qos constraints"
    - "delay optimal scheduling of arbitrarily bursty traffic over multi state time varying channels"
    - "what will 5g be"
    - "framework for link level energy efficiency optimization with informed transmitter"

Connected through hyperedge HE-2 (induced by source paper "optimum transmission rate in fading channels with markovian sources and qos constraints"):
  with members:
    - "on the effective energy efficiency of ultra reliable networks in the finite blocklength regime"
    - "ultra reliable communication in 5g wireless systems"

Connected through hyperedge HE-3 (induced by source paper "energy efficient ofdma networks maintaining statistical qos guarantees for delay sensitive traffic"):
  with members:
    - "distributed energy spectral efficiency optimization for partial full interference alignment in multi user multi relay multi cell mimo systems"
    - "large scale mimo is capable of eliminating power thirsty channel coding for wireless transmission of hevc h 265 video"
    - "spectral and energy spectral efficiency optimization of joint transmit and receive beamforming based multi relay mimo ofdma cellular networks"
    - "maximizing energy efficiency in multi relay ofdma cellular networks"
    - "achieving maximum energy efficiency in multi relay ofdma cellular networks a fractional programming approach"
    - "qos aware base station selections for distributed mimo links in broadband wireless networks"
    - "statistical delay control and qos driven power allocation over two hop wireless relay links"

Connected through hyperedge HE-4 (induced by source paper "delay optimal scheduling of arbitrarily bursty traffic over multi state time varying channels"):
  with members:
    - "what will 5g be"

Connected through hyperedge HE-5 (induced by source paper "on the throughput of multi source multi destination relay networks with queueing constraints"):
  with members:
    - "effective capacity of two hop wireless communication systems"
    - "on the achievable throughput region of multiple access fading channels with qos constraints"

Connected through hyperedge HE-6 (induced by source paper "secure wireless communication and optimal power control under statistical queueing constraints"):
  with members:
    - "secure broadcasting over fading channels with statistical qos constraints"
    - "secure communication over fading channels with statistical qos constraints"
    - "on the delay limited secrecy capacity of fading channels"
    - "discrete memoryless interference and broadcast channels with confidential messages secrecy rate regions"
    - "secrecy capacity of a class of broadcast channels with an eavesdropper"
    - "analysis of energy efficiency in fading channels under qos constraints"

Connected through hyperedge HE-7 (induced by source paper "channel coding over multiple coherence blocks with queueing constraints"):
  with members:
    - "throughput analysis of buffer constrained wireless systems in the finite blocklength regime"
    - "coding versus arq in fading channels how reliable should the phy be"
    - "analysis of energy efficiency in fading channels under qos constraints"

Connected through hyperedge HE-8 (induced by source paper "throughput analysis of buffer constrained wireless systems in the finite blocklength regime"):
  with members:
    - "coding versus arq in fading channels how reliable should the phy be"
    - "energy efficiency of fixed rate wireless transmissions under queueing constraints and channel uncertainty"
    - "analysis of energy efficiency in fading channels under qos constraints"

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)