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: "on the performance of backhaul constrained cell free massive mimo with linear receivers"
  Abstract: Limited-backhaul cell-free Massive multiple-input multiple-output (MIMO), in which the fog radio access network (F-RAN) is implemented to exchange the information between access points (APs) and the central processing unit (CPU), is investigated. We introduce a novel approach where the APs estimate the channel and send back the quantized version of the estimated channel and the quantized version of the received signal to the central processing unit. The Max algorithm and the Bussgang theorem are exploited to model the optimum uniform quantization. The ergodic achievable rates are derived. We show that exploiting microwave wireless backhaul links and using a small number of bits to quantize the estimated channel and the received signal, the performance of limited-backhaul cell-free Massive MIMO closely approaches the performance of cell-free Massive MIMO with perfect backhaul links.

Connected through hyperedge HE-1 (induced by source paper "multiple antenna technologies for beyond 5g"):
  with members:
    - "intelligent reflecting surface versus decode and forward how large surfaces are needed to beat relaying"
    - "robust trajectory and resource allocation design for secure uav aided communications"
    - "a new look at cell free massive mimo making it practical with dynamic cooperation"
    - "scalability aspects of cell free massive mimo"
    - "cascaded channel estimation for large intelligent metasurface assisted massive mimo"
    - "robust and secure wireless communications via intelligent reflecting surfaces"
    - "channel estimation for intelligent reflecting surface assisted multiuser communications framework algorithms and analysis"
    - "resource allocation for secure irs assisted multiuser miso systems"

Connected through hyperedge HE-2 (induced by source paper "scalable cell free massive mimo systems"):
  with members:
    - "a new look at cell free massive mimo making it practical with dynamic cooperation"
    - "scalability aspects of cell free massive mimo"
    - "making cell free massive mimo competitive with mmse processing and centralized implementation"
    - "covariance matrix estimation for massive mimo"
    - "massive mimo in sub 6 ghz and mmwave physical practical and use case differences"
    - "fog massive mimo a user centric seamless hot spot architecture"
    - "covariance matrix estimation in massive mimo"
    - "massive mimo has unlimited capacity"

Connected through hyperedge HE-3 (induced by source paper "making cell free massive mimo competitive with mmse processing and centralized implementation"):
  with members:
    - "ubiquitous cell free massive mimo communications"
    - "large scale fading decoding in cellular massive mimo systems with spatially correlated channels"
    - "few bit csi acquisition for centralized cell free massive mimo with spatial correlation"
    - "can massive mimo support uplink intensive applications"
    - "massive mimo has unlimited capacity"
    - "performance of cell free massive mimo systems with mmse and lsfd receivers"
    - "on the total energy efficiency of cell free massive mimo"
    - "uplink interference reduction in large scale antenna systems"

Connected through hyperedge HE-4 (induced by source paper "max min rate of cell free massive mimo uplink with optimal uniform quantization"):
  with members:
    - "on the uplink throughput of zero forcing in cell free massive mimo with coarse quantization"
    - "ubiquitous cell free massive mimo communications"
    - "on the energy efficiency of limited backhaul cell free massive mimo"
    - "cell free massive mimo with limited backhaul"
    - "cooperative access networks optimum fronthaul quantization in distributed massive mimo and cloud ran"
    - "network deployment for maximal energy efficiency in uplink with multislope path loss"
    - "enhanced max min sinr for uplink cell free massive mimo systems"
    - "performance of cell free massive mimo systems with mmse and lsfd receivers"

Connected through hyperedge HE-5 (induced by source paper "on the energy efficiency of limited backhaul cell free massive mimo"):
  with members:
    - "on the uplink throughput of zero forcing in cell free massive mimo with coarse quantization"
    - "cooperative access networks optimum fronthaul quantization in distributed massive mimo and cloud ran"
    - "enhanced max min sinr for uplink cell free massive mimo systems"
    - "on the total energy efficiency of cell free massive mimo"
    - "robust geometry based user scheduling for large mimo systems under realistic channel conditions"
    - "cell free massive mimo versus small cells"
    - "optimal design of energy efficient multi user mimo systems is massive mimo the answer"

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)