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: "spectral efficiency of multipair massive mimo two way relaying with hardware impairments"
  Abstract: We consider a multipair massive multiple-input multiple-output (MIMO) two-way relaying system, where multiple pairs of single-antenna devices exchange data with the help of a relay employing a large number of antennas $N$. The relay consists of low-cost components that suffer from hardware impairments. A large-scale approximation of the spectral efficiency (SE) with maximum ratio (MR) processing is derived in closed form, and the approximation is tight as $N \to \infty$. It is revealed that for a fixed hardware quality, the impact of the hardware impairments vanishes asymptotically when $N$ grows large. Moreover, the impact of the impairments may even vanish when the hardware quality is gradually decreased with $N$, if a scaling law is satisfied. Finally, numerical results validate that multipair massive MIMO two-way relaying systems are robust to hardware impairments at the relay.

Connected through hyperedge HE-1 (induced by source paper "design of an miso swipt aided code index modulated multi carrier m dcsk system for e health iot"):
  with members:
    - "fundamentals of wireless information and power transfer from rf energy harvester models to signal and system designs"
    - "modulation design for wireless information and power transfer with nonlinear energy harvester modeling"
    - "rate energy region in wireless information and power transfer new receiver architecture and practical modulation"
    - "performance analysis of mixed adc massive mimo systems over rician fading channels"
    - "on the feasibility of wireless energy transfer using massive antenna arrays"
    - "achievable rate of rician large scale mimo channels with transceiver hardware impairments"
    - "iterative dynamic water filling for fading multiple access channels with energy harvesting"
    - "multiuser miso beamforming for simultaneous wireless information and power transfer"

Connected through hyperedge HE-2 (induced by source paper "transmission strategies for cell free massive mimo with limited capacity fronthaul links"):
  with members:
    - "cell free massive mimo with limited backhaul"
    - "spectral and energy efficiency of cell free massive mimo systems with hardware impairments"
    - "on the total energy efficiency of cell free massive mimo"
    - "channel hardening and favorable propagation in cell free massive mimo with stochastic geometry"
    - "energy efficiency in cell free massive mimo with zero forcing precoding design"
    - "analysis and design of secure massive mimo systems in the presence of hardware impairments"
    - "cell free massive mimo versus small cells"
    - "compute and forward in cell free massive mimo great performance with low backhaul load"

Connected through hyperedge HE-3 (induced by source paper "mixed adc dac multipair massive mimo relaying systems performance analysis and power optimization"):
  with members:
    - "all technologies work together for good a glance to future mobile networks"
    - "on low resolution adcs in practical 5g millimeter wave massive mimo systems"
    - "spectral efficiency of mixed adc massive mimo"
    - "multipair massive mimo relaying systems with one bit adc s and dac s"
    - "on performance of quantized transceiver in multiuser massive mimo downlinks"
    - "the distributed mimo scenario can ideal adcs be replaced by low resolution adcs"
    - "channel estimation and performance analysis of one bit massive mimo systems"
    - "on the total energy efficiency of cell free massive mimo"

Connected through hyperedge HE-4 (induced by source paper "power efficient and secure wpcns with hardware impairments and non linear eh circuit"):
  with members:
    - "fundamental green tradeoffs progresses challenges and impacts on 5g networks"
    - "max min fair beamforming for swipt systems with non linear eh model"
    - "power allocation for secure swipt systems with wireless powered cooperative jamming"
    - "robust resource allocation for mimo wireless powered communication networks based on a non linear eh model"
    - "analysis and design of secure massive mimo systems in the presence of hardware impairments"
    - "on the spectral efficiency of massive mimo systems with low resolution adcs"
    - "wireless powered communication networks an overview"
    - "secrecy wireless information and power transfer challenges and opportunities"

Connected through hyperedge HE-5 (induced by source paper "impact of spatial filtering on distortion from low noise amplifiers in massive mimo base stations"):
  with members:
    - "spatial characteristics of distortion radiated from antenna arrays with transceiver nonlinearities"
    - "throughput analysis of massive mimo uplink with low resolution adcs"
    - "achievable uplink rates for massive mimo with coarse quantization"
    - "on energy efficient uplink multi user mimo with shared lna control"
    - "uplink performance of wideband massive mimo with one bit adcs"
    - "out of band radiation from large antenna arrays"
    - "a survey of energy efficient techniques for 5g networks and challenges ahead"
    - "massive mimo with non ideal arbitrary arrays hardware scaling laws and circuit aware design"

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)