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: "a general robust linear transceiver design for multi hop amplify and forward mimo relaying systems"
  Abstract: In this paper, linear transceiver design for multi-hop amplify-and-forward (AF) multi-input multi-output (MIMO) relaying systems with Gaussian distributed channel estimation errors is investigated. Commonly used transceiver design criteria including weighted mean-square-error (MSE) minimization, capacity maximization, worst-MSE/MAX-MSE minimization and weighted sum-rate maximization, are considered and unified into a single matrix-variate optimization problem. A general robust design algorithm is proposed to solve the unified problem. Specifically, by exploiting majorization theory and properties of matrix-variate functions, the optimal structure of the robust transceiver is derived when either the covariance matrix of channel estimation errors seen from the transmitter side or the corresponding covariance matrix seen from the receiver side is proportional to an identity matrix. Based on the optimal structure, the original transceiver design problems are reduced to much simpler problems with only scalar variables whose solutions are readily obtained by an iterative water-filling algorithm. A number of existing transceiver design algorithms are found to be special cases of the proposed solution. The differences between our work and the existing related work are also discussed in detail. The performance advantages of the proposed robust designs are demonstrated by simulation results.

Connected through hyperedge HE-1 (induced by source paper "hybrid transceiver optimization for multi hop communications"):
  with members:
    - "hybrid beamforming for millimeter wave systems using the mmse criterion"
    - "majorization minimization aided hybrid transceivers for mimo interference channels"
    - "hybrid precoding architecture for massive multiuser mimo with dissipation sub connected or fully connected structures"
    - "hybrid beamforming with selection for multiuser massive mimo systems"
    - "spectral efficiency optimization for millimeter wave multiuser mimo systems"
    - "spectral and energy efficiency of multi pair massive mimo relay network with hybrid processing"
    - "multi user precoding and channel estimation for hybrid millimeter wave systems"
    - "alternating minimization algorithms for hybrid precoding in millimeter wave mimo systems"

Connected through hyperedge HE-2 (induced by source paper "a survey on mimo transmission with discrete input signals technical challenges advances and future trends"):
  with members:
    - "asymptotic performance analysis of a k hop amplify and forward relay mimo channel"
    - "iterative distributed minimum total mse approach for secure communications in mimo interference channels"
    - "asymptotic analysis of su mimo channels with transmitter noise and mismatched joint decoding"
    - "secure massive mimo transmission with an active eavesdropper"
    - "interference aligned space time transmission with diversity for the 2 times 2 x network"
    - "space time encoded miso broadcast channel with outdated csit an error rate and diversity performance analysis"
    - "high snr asymptotics of mutual information for discrete constellations with applications to bicm"
    - "differential distributed space time coding with imperfect synchronization in frequency selective channels"

Connected through hyperedge HE-3 (induced by source paper "on weighted mse model for mimo transceiver optimization"):
  with members:
    - "a framework for transceiver designs for multi hop communications with covariance shaping constraints"
    - "matrix monotonic optimization for mimo systems"
    - "transceiver design for dual hop nonregenerative mimo ofdm relay systems under channel uncertainties"

Connected through hyperedge HE-4 (induced by source paper "energy harvesting noncoherent cooperative communications"):
  with members:
    - "wireless networks with rf energy harvesting a contemporary survey"
    - "power allocation strategies in energy harvesting wireless cooperative networks"
    - "simultaneous information and energy transfer in large scale networks with without relaying"
    - "throughput maximization in wireless powered communication networks"
    - "cooperative energy harvesting networks with spatially random users"
    - "matrix monotonic optimization for mimo systems"
    - "simultaneous information and power transfer for broadband wireless systems"
    - "relaying protocols for wireless energy harvesting and information processing"

Connected through hyperedge HE-5 (induced by source paper "a framework for transceiver designs for multi hop communications with covariance shaping constraints"):
  with members:
    - "evolution toward 5g multi tier cellular wireless networks an interference management perspective"
    - "beamforming for miso interference channels with qos and rf energy transfer"
    - "matrix monotonic optimization for mimo systems"
    - "robust transceiver with tomlinson harashima precoding for amplify and forward mimo relaying systems"
    - "a tutorial on the optimization of amplify and forward mimo relay systems"
    - "transceiver design for dual hop nonregenerative mimo ofdm relay systems under channel uncertainties"
    - "ergodic capacity analysis of amplify and forward mimo dual hop systems"

Connected through hyperedge HE-6 (induced by source paper "robust mmse precoding for multiuser mimo relay systems using switched relaying and side information"):
  with members:
    - "multi branch tomlinson harashima precoding design for mu mimo systems theory and algorithms"
    - "adaptive distributed space time coding based on adjustable code matrices for cooperative mimo relaying systems"
    - "mimo relaying broadcast channels with linear precoding and quantized channel state information feedback"

Connected through hyperedge HE-7 (induced by source paper "transceiver designs with matrix version water filling architecture under mixed power constraints"):
  with members:
    - "miso capacity with per antenna power constraint"

Connected through hyperedge HE-8 (induced by source paper "quality of service improvement for high speed railway communications"):
  with members:
    - "robust transceiver with tomlinson harashima precoding for amplify and forward mimo relaying 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)