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: "spectrum allocation in two tier networks"
  Abstract: Two-tier networks, comprising a conventional cellular network overlaid with shorter range hotspots (e.g. femtocells, distributed antennas, or wired relays), offer an economically viable way to improve cellular system capacity. The capacity-limiting factor in such networks is interference. The cross-tier interference between macrocells and femtocells can suffocate the capacity due to the near-far problem, so in practice hotspots should use a different frequency channel than the potentially nearby high-power macrocell users. Centralized or coordinated frequency planning, which is difficult and inefficient even in conventional cellular networks, is all but impossible in a two-tier network. This paper proposes and analyzes an optimum decentralized spectrum allocation policy for two-tier networks that employ frequency division multiple access (including OFDMA). The proposed allocation is optimal in terms of Area Spectral Efficiency (ASE), and is subjected to a sensible Quality of Service (QoS) requirement, which guarantees that both macrocell and femtocell users attain at least a prescribed data rate. Results show the dependence of this allocation on the QoS requirement, hotspot density and the co-channel interference from the macrocell and surrounding femtocells. Design interpretations of this result are provided.

Connected through hyperedge HE-1 (induced by source paper "partially distributed resource allocation in small cell networks"):
  with members:
    - "heterogeneous cellular networks with flexible cell association a comprehensive downlink sinr analysis"
    - "modeling and analysis of k tier downlink heterogeneous cellular networks"
    - "a tractable approach to coverage and rate in cellular networks"
    - "power control in two tier femtocell networks"
    - "femtocell networks a survey"

Connected through hyperedge HE-2 (induced by source paper "open closed and shared access femtocells in the downlink"):
  with members:
    - "heterogeneous cellular networks with flexible cell association a comprehensive downlink sinr analysis"
    - "fundamentals of inter cell overhead signaling in heterogeneous cellular networks"
    - "modeling and analysis of k tier downlink heterogeneous cellular networks"
    - "open vs closed access femtocells in the uplink"
    - "self optimized coverage coordination in femtocell networks"
    - "power control in two tier femtocell networks"
    - "coverage in multi antenna two tier networks"
    - "interference mitigation using uplink power control for two tier femtocell networks"

Connected through hyperedge HE-3 (induced by source paper "heterogeneous cellular networks with flexible cell association a comprehensive downlink sinr analysis"):
  with members:
    - "modeling and analysis of k tier downlink heterogeneous cellular networks"
    - "a tractable approach to coverage and rate in cellular networks"
    - "self optimized coverage coordination in femtocell networks"
    - "coverage in multi antenna two tier networks"
    - "interference mitigation using uplink power control for two tier femtocell networks"
    - "femtocell networks a survey"
    - "uplink capacity and interference avoidance for two tier femtocell networks"

Connected through hyperedge HE-4 (induced by source paper "an overview of the transmission capacity of wireless networks"):
  with members:
    - "spatial multiplexing with mmse receivers single stream optimality in ad hoc networks"
    - "random access transport capacity"
    - "performance of optimum combining in a poisson field of interferers and rayleigh fading channels"
    - "transmission capacities for overlaid wireless ad hoc networks with outage constraints"
    - "transmission capacity of ad hoc networks with multiple antennas using transmit stream adaptation and interference cancelation"
    - "outage local throughput and capacity of random wireless networks"
    - "interference and outage in clustered wireless ad hoc networks"
    - "spatial interference cancellation for multi antenna mobile ad hoc networks"

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.NI(Networking and Internet Architecture)