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: "decentralized baseband processing for massive mu mimo systems"
  Abstract: Achieving high spectral efficiency in realistic massive multi-user (MU) multiple-input multiple-output (MIMO) wireless systems requires computationally-complex algorithms for data detection in the uplink (users transmit to base-station) and beamforming in the downlink (base-station transmits to users). Most existing algorithms are designed to be executed on centralized computing hardware at the base-station (BS), which results in prohibitive complexity for systems with hundreds or thousands of antennas and generates raw baseband data rates that exceed the limits of current interconnect technology and chip I/O interfaces. This paper proposes a novel decentralized baseband processing architecture that alleviates these bottlenecks by partitioning the BS antenna array into clusters, each associated with independent radio-frequency chains, analog and digital modulation circuitry, and computing hardware. For this architecture, we develop novel decentralized data detection and beamforming algorithms that only access local channel-state information and require low communication bandwidth among the clusters. We study the associated trade-offs between error-rate performance, computational complexity, and interconnect bandwidth, and we demonstrate the scalability of our solutions for massive MU-MIMO systems with thousands of BS antennas using reference implementations on a graphic processing unit (GPU) cluster.

Connected through hyperedge HE-1 (induced by source paper "cell free massive mimo with radio stripes and sequential uplink processing"):
  with members:
    - "decentralized equalization with feedforward architectures for massive mu mimo"
    - "ubiquitous cell free massive mimo communications"
    - "design trade offs for decentralized baseband processing in massive mu mimo systems"
    - "making cell free massive mimo competitive with mmse processing and centralized implementation"
    - "cell free massive mimo versus small cells"

Connected through hyperedge HE-2 (induced by source paper "decentralized equalization with feedforward architectures for massive mu mimo"):
  with members:
    - "gaussian message passing for overloaded massive mimo noma"
    - "feedforward architectures for decentralized precoding in massive mu mimo systems"
    - "efficient dsp and circuit architectures for massive mimo state of the art and future directions"
    - "optimally tuned nonparametric linear equalization for massive mu mimo systems"
    - "on the achievable rates of decentralized equalization in massive mu mimo systems"
    - "on the performance of mismatched data detection in large mimo systems"
    - "performance trade offs in multi processor approximate message passing"
    - "the world s first real time testbed for massive mimo design implementation and validation"

Connected through hyperedge HE-3 (induced by source paper "design trade offs for decentralized baseband processing in massive mu mimo systems"):
  with members:
    - "decentralized coordinate descent data detection and precoding for massive mu mimo"
    - "decentralized equalization with feedforward architectures for massive mu mimo"
    - "feedforward architectures for decentralized precoding in massive mu mimo systems"
    - "on the achievable rates of decentralized equalization in massive mu mimo systems"
    - "quantized precoding for massive mu mimo"
    - "what will 5g be"

Connected through hyperedge HE-4 (induced by source paper "decentralized coordinate descent data detection and precoding for massive mu mimo"):
  with members:
    - "decentralized equalization with feedforward architectures for massive mu mimo"
    - "feedforward architectures for decentralized precoding in massive mu mimo systems"
    - "on the achievable rates of decentralized equalization in massive mu mimo systems"
    - "massive mimo for next generation wireless systems"
    - "what will 5g be"

Connected through hyperedge HE-5 (induced by source paper "efficient dsp and circuit architectures for massive mimo state of the art and future directions"):
  with members:
    - "beyond massive mimo the potential of data transmission with large intelligent surfaces"
    - "out of band radiation from antenna arrays clarified"
    - "spatial characteristics of distortion radiated from antenna arrays with transceiver nonlinearities"
    - "performance characterization of a real time massive mimo system with los mobile channels"
    - "channel estimation and performance analysis of one bit massive mimo systems"
    - "on out of band emissions of quantized precoding in massive mu mimo ofdm"
    - "achievable uplink rates for massive mimo with coarse quantization"
    - "impact of spatial filtering on distortion from low noise amplifiers in massive mimo base stations"

Connected through hyperedge HE-6 (induced by source paper "feedforward architectures for decentralized precoding in massive mu mimo systems"):
  with members:
    - "on the achievable rates of decentralized equalization in massive mu mimo systems"
    - "cell free massive mimo versus small cells"
    - "quantized precoding for massive mu mimo"
    - "what will 5g be"

Connected through hyperedge HE-7 (induced by source paper "1 bit massive mu mimo precoding in vlsi"):
  with members:
    - "channel estimation and performance analysis of one bit massive mimo systems"
    - "uplink performance of wideband massive mimo with one bit adcs"
    - "massive mu mimo ofdm downlink with one bit dacs and linear precoding"
    - "nonlinear 1 bit precoding for massive mu mimo with higher order modulation"
    - "minimum ber precoding in 1 bit massive mimo systems"
    - "data detection in large multi antenna wireless systems via approximate semidefinite relaxation"
    - "performance of the wideband massive uplink mimo with one bit adcs"
    - "high throughput data detection for massive mu mimo ofdm using coordinate descent"

Connected through hyperedge HE-8 (induced by source paper "nonlinear precoding for phase quantized constant envelope massive mu mimo ofdm"):
  with members:
    - "1 bit massive mu mimo precoding in vlsi"
    - "branch and bound precoding for multiuser mimo systems with 1 bit quantization"
    - "linear precoding with low resolution dacs for massive mu mimo ofdm downlink"
    - "minimum ber precoding in 1 bit massive mimo systems"
    - "quantized precoding for massive mu mimo"
    - "massive mimo for next generation wireless systems"
    - "five disruptive technology directions for 5g"
    - "constant envelope multi user precoding for frequency selective massive mimo systems"

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)