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: "implementation of physical layer network coding"
  Abstract: This paper presents the first implementation of a two-way relay network based on the principle of physical-layer network coding. To date, only a simplified version of physical-layer network coding (PNC) method, called analog network coding (ANC), has been successfully implemented. The advantage of ANC is that it is simple to implement; the disadvantage, on the other hand, is that the relay amplifies the noise along with the signal before forwarding the signal. PNC systems in which the relay performs XOR or other denoising PNC mappings of the received signal have the potential for significantly better performance. However, the implementation of such PNC systems poses many challenges. For example, the relay must be able to deal with symbol and carrier-phase asynchronies of the simultaneous signals received from the two end nodes, and the relay must perform channel estimation before detecting the signals. We investigate a PNC implementation in the frequency domain, referred to as FPNC, to tackle these challenges. FPNC is based on OFDM. In FPNC, XOR mapping is performed on the OFDM samples in each subcarrier rather than on the samples in the time domain. We implement FPNC on the universal soft radio peripheral (USRP) platform. Our implementation requires only moderate modifications of the packet preamble design of 802.11a/g OFDM PHY. With the help of the cyclic prefix (CP) in OFDM, symbol asynchrony and the multi-path fading effects can be dealt with in a similar fashion. Our experimental results show that symbol-synchronous and symbol-asynchronous FPNC have essentially the same BER performance, for both channel-coded and unchannel-coded FPNC.

Connected through hyperedge HE-1 (induced by source paper "coherent detection for short packet physical layer network coding with fsk modulation"):
  with members:
    - "noncoherent detection for physical layer network coding"
    - "practical power balanced non orthogonal multiple access"
    - "ultra reliable short packet communications half duplex or full duplex relaying"
    - "complex linear physical layer network coding"
    - "mobile lattice coded physical layer network coding with practical channel alignment"
    - "on the subtleties of q pam linear physical layer network coding"
    - "reliable physical layer network coding supporting real applications"
    - "ultra reliable communication in 5g wireless systems"

Connected through hyperedge HE-2 (induced by source paper "implementation of uplink network coded modulation for two hop networks"):
  with members:
    - "complex linear physical layer network coding"
    - "asynchronous convolutional coded physical layer network coding"
    - "network coded multiple access"
    - "wireless network coding via modified 802 11 mac phy design and implementation on sdr"
    - "asynchronous physical layer network coding"
    - "physical layer network coding"

Connected through hyperedge HE-3 (induced by source paper "mobile lattice coded physical layer network coding with practical channel alignment"):
  with members:
    - "reliable physical layer network coding supporting real applications"
    - "phase precoded compute and forward with partial feedback"
    - "asynchronous convolutional coded physical layer network coding"
    - "multilevel coding schemes for compute and forward with flexible decoding"
    - "scalable synchronization and reciprocity calibration for distributed multiuser mimo"
    - "network coded multiple access"
    - "airsync enabling distributed multiuser mimo with full spatial multiplexing"
    - "the degrees of freedom of compute and forward"

Connected through hyperedge HE-4 (induced by source paper "on the subtleties of q pam linear physical layer network coding"):
  with members:
    - "multilevel coding schemes for compute and forward with flexible decoding"
    - "symbol and bit mapping optimization for physical layer network coding with pulse amplitude modulation"
    - "an algebraic approach to physical layer network coding"
    - "asynchronous physical layer network coding"
    - "multiple input multiple output two way relaying a space division approach"
    - "reliable physical layer network coding"
    - "physical layer network coding tutorial survey and beyond"
    - "channel coding and decoding in a relay system operated with physical layer network coding"

Connected through hyperedge HE-5 (induced by source paper "reliable physical layer network coding supporting real applications"):
  with members:
    - "on the subtleties of q pam linear physical layer network coding"
    - "arq for physical layer network coding"
    - "building blocks of physical layer network coding"
    - "network coded multiple access"
    - "distributed mac protocol supporting physical layer network coding"
    - "reliable physical layer network coding"
    - "physical layer network coding tutorial survey and beyond"

Connected through hyperedge HE-6 (induced by source paper "physical layer network coding in two way heterogeneous cellular networks with power imbalance"):
  with members:
    - "what will 5g be"
    - "network coded multiple access"
    - "asynchronous physical layer network coding"
    - "physical layer network coding tutorial survey and beyond"

Connected through hyperedge HE-7 (induced by source paper "source and physical layer network coding for correlated two way relaying"):
  with members:
    - "compressed relaying for two way relay networks with correlated sources"
    - "a distributed differential space time coding scheme with analog network coding in two way relay networks"
    - "physical layer network coding tutorial survey and beyond"
    - "network information flow with correlated sources"

Connected through hyperedge HE-8 (induced by source paper "network coded multiple access with high order modulations"):
  with members:
    - "on the subtleties of q pam linear physical layer network coding"
    - "coded random access applying codes on graphs to design random access protocols"
    - "uplink non orthogonal multiple access for 5g wireless networks"
    - "network coded multiple access"
    - "constellation mapping for physical layer network coding with m qam modulation"
    - "asynchronous physical layer network coding"
    - "random access with physical layer network coding"
    - "airsync enabling distributed multiuser mimo with full spatial multiplexing"

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)