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: "qpsk waveform for mimo radar with spectrum sharing constraints"
  Abstract: Multiple-input multiple-output (MIMO) radar is a relatively new concept in the field of radar signal processing. Many novel MIMO radar waveforms have been developed by considering various performance metrics and constraints. In this paper, we show that finite alphabet constant-envelope (FACE) quadrature-pulse shift keying (QPSK) waveforms can be designed to realize a given covariance matrix by transforming a constrained nonlinear optimization problem into an unconstrained nonlinear optimization problem. In addition, we design QPSK waveforms in a way that they do not cause interference to cellular system, by steering nulls towards a selected base station (BS). The BS is selected according to our algorithm which guarantees minimum degradation in radar performance due to null space projection (NSP) of radar waveforms. We design QPSK waveforms with spectrum sharing constraints for stationary and moving radar platform. We show that the waveform designed for stationary MIMO radar matches the desired beampattern closely, when the number of BS antennas N BS is considerably less than the number of radar antennas M , due to quasi-static interference channel. However, for moving radar the difference between designed and desired waveforms is larger than stationary radar, due to rapidly changing wireless channel.

Connected through hyperedge HE-1 (induced by source paper "coexistence analysis between radar and cellular system in los channel"):
  with members:
    - "separation of signals consisting of amplitude and instantaneous frequency rrc pulses using snr uniform training"
    - "target detection performance of spectrum sharing mimo radars"
    - "overlapped mimo radar waveform design for coexistence with communication systems"
    - "radar precoder design for spectral coexistence with coordinated multi point comp system"
    - "a utility proportional fairness resource allocation in spectrally radar coexistent cellular networks"
    - "on the impact of time varying interference channel on the spatial approach of spectrum sharing between s band radar and communication system"

Connected through hyperedge HE-2 (induced by source paper "network mimo with partial cooperation between radar and cellular systems"):
  with members:
    - "target detection performance of spectrum sharing mimo radars"
    - "on the impact of time varying interference channel on the spatial approach of spectrum sharing between s band radar and communication system"
    - "linear precoding and equalization for network mimo with partial cooperation"
    - "networked mimo with clustered linear precoding"

Connected through hyperedge HE-3 (induced by source paper "3d channel modeling between seaborne mimo radar and mimo cellular system"):
  with members:
    - "coexistence analysis between radar and cellular system in los channel"
    - "target detection performance of spectrum sharing mimo radars"
    - "overlapped mimo radar waveform design for coexistence with communication systems"
    - "a utility proportional fairness resource allocation in spectrally radar coexistent cellular networks"
    - "on the impact of time varying interference channel on the spatial approach of spectrum sharing between s band radar and communication system"
    - "preliminary results on 3d channel modeling from theory to standardization"

Connected through hyperedge HE-4 (induced by source paper "target detection performance of spectrum sharing mimo radars"):
  with members:
    - "coexistence analysis between radar and cellular system in los channel"
    - "3d channel modeling between seaborne mimo radar and mimo cellular system"
    - "overlapped mimo radar waveform design for coexistence with communication systems"
    - "radar precoder design for spectral coexistence with coordinated multi point comp system"
    - "a utility proportional fairness resource allocation in spectrally radar coexistent cellular networks"
    - "on the impact of time varying interference channel on the spatial approach of spectrum sharing between s band radar and communication system"

Connected through hyperedge HE-5 (induced by source paper "three dimensional 3d channel modeling between seaborne mimo radar and mimo cellular system"):
  with members:
    - "target detection performance of spectrum sharing mimo radars"
    - "overlapped mimo radar waveform design for coexistence with communication systems"
    - "a utility proportional fairness resource allocation in spectrally radar coexistent cellular networks"
    - "on the impact of time varying interference channel on the spatial approach of spectrum sharing between s band radar and communication system"
    - "preliminary results on 3d channel modeling from theory to standardization"

Connected through hyperedge HE-6 (induced by source paper "radar precoder design for spectral coexistence with coordinated multi point comp system"):
  with members:
    - "target detection performance of spectrum sharing mimo radars"
    - "a utility proportional fairness resource allocation in spectrally radar coexistent cellular networks"
    - "on the impact of time varying interference channel on the spatial approach of spectrum sharing between s band radar and communication system"

Connected through hyperedge HE-7 (induced by source paper "on the impact of time varying interference channel on the spatial approach of spectrum sharing between s band radar and communication system"):
  with members:
    - "optimal downlink power allocation in cellular networks"
    - "3d channel modeling between seaborne mimo radar and mimo cellular system"
    - "target detection performance of spectrum sharing mimo radars"
    - "a utility proportional fairness resource allocation in spectrally radar coexistent cellular 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)