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: "interference alignment and soft space reuse based cooperative transmission for multi cell massive mimo networks"
  Abstract: As a revolutionary wireless transmission strategy, interference alignment (IA) can improve the capacity of the cell-edge users. However, the acquisition of the global channel state information (CSI) for IA leads to unacceptable overhead in the massive MIMO systems. To tackle this problem, in this paper, we propose an IA and soft-space-reuse (IA-SSR) based cooperative transmission scheme under the two-stage precoding framework. Specifically, the cell-center and the cell-edge users are separately treated to fully exploit the spatial degrees of freedoms (DoF). Then, the optimal power allocation policy is developed to maximize the sum-capacity of the network. Next, a low-cost channel estimator is designed for the proposed IA-SSR framework. Some practical issues in IA-SSR implementation are also discussed. Finally, plenty of numerical results are presented to show the efficiency of the proposed algorithm.

Connected through hyperedge HE-1 (induced by source paper "downlink secrecy rate of one bit massive mimo system with active eavesdropping"):
  with members:
    - "robust designs of beamforming and power splitting for distributed antenna systems with wireless energy harvesting"
    - "secure massive mimo communication with low resolution dacs"
    - "on the uplink achievable rate for massive mimo with 1 bit adc and superimposed pilots"
    - "data aided secure massive mimo transmission with active eavesdropping"
    - "secure massive mimo systems with limited rf chains"
    - "secure transmission with large numbers of antennas and finite alphabet inputs"
    - "jamming resistant receivers for the massive mimo uplink"
    - "beamforming and power splitting designs for an aided secure multi user mimo swipt systems"

Connected through hyperedge HE-2 (induced by source paper "time varying downlink channel tracking for quantized massive mimo networks"):
  with members:
    - "beamspace aware adaptive channel estimation for single carrier time varying massive mimo channels"
    - "bayesian optimal data detector for mmwave ofdm system with low resolution adc"
    - "a gamp based low complexity sparse bayesian learning algorithm"
    - "mixed adc massive mimo detectors performance analysis and design optimization"
    - "uplink achievable rate for massive mimo systems with low resolution adc"
    - "spatially common sparsity based adaptive channel estimation and feedback for fdd massive mimo"
    - "training sequence design for feedback assisted hybrid beamforming in massive mimo systems"
    - "two tier precoding for fdd multi cell massive mimo time varying interference networks"

Connected through hyperedge HE-3 (induced by source paper "time varying massive mimo channel estimation capturing reconstruction and restoration"):
  with members:
    - "efficient downlink channel reconstruction for fdd multi antenna systems"
    - "channel estimation for tdd fdd massive mimo systems with channel covariance computing"
    - "channel acquisition for massive mimo ofdm with adjustable phase shift pilots"
    - "design and implementation of a tdd based 128 antenna massive mimo prototyping system"
    - "uplink achievable rate for massive mimo systems with low resolution adc"
    - "spatially common sparsity based adaptive channel estimation and feedback for fdd massive mimo"
    - "millimeter wave mimo with lens antenna array a new path division multiplexing paradigm"
    - "training sequence design for feedback assisted hybrid beamforming in massive mimo systems"

Connected through hyperedge HE-4 (induced by source paper "joint precoding and power control in small cell networks with proportional rate miso bc backhaul"):
  with members:
    - "secure distributed on device learning networks with byzantine adversaries"
    - "robust energy efficient beamforming in misome swipt systems with proportional secrecy rate"
    - "cache enabled physical layer security for video streaming in backhaul limited cellular networks"
    - "fronthaul aware group sparse precoding and signal splitting in swipt c ran"
    - "downlink energy efficiency of power allocation and wireless backhaul bandwidth allocation in heterogeneous small cell networks"
    - "fronthauling for 5g lte u ultra dense cloud small cell networks"
    - "heterogeneous cellular networks using wireless backhaul fast admission control and large system analysis"

Connected through hyperedge HE-5 (induced by source paper "two high performance amplitude beamforming schemes for secure precise communication and jamming with phase alignment"):
  with members:
    - "two high performance schemes of transmit antenna selection for secure spatial modulation"
    - "secure transmission with large numbers of antennas and finite alphabet inputs"
    - "artificial noise aided secure multicast precoding for directional modulation systems"
    - "artificial noise aided secure transmission with directional modulation based on random frequency diverse arrays"

Connected through hyperedge HE-6 (induced by source paper "time varying channel tracking for multi uav wideband communications with beam squint"):
  with members:
    - "energy efficient uav communication with trajectory optimization"
    - "wireless communications with unmanned aerial vehicles opportunities and challenges"
    - "millimeter wave cellular wireless networks potentials and challenges"

Connected through hyperedge HE-7 (induced by source paper "performance analysis of multi cell millimeter wave massive mimo networks with low precision adcs"):
  with members:
    - "on low resolution adcs in practical 5g millimeter wave massive mimo systems"
    - "a hardware efficient analog network structure for hybrid precoding in millimeter wave systems"
    - "a comparison of hybrid beamforming and digital beamforming with low resolution adcs for multiple users and imperfect csi"
    - "secure massive mimo systems with limited rf chains"
    - "on performance of quantized transceiver in multiuser massive mimo downlinks"
    - "spectral and energy efficiency of multi pair massive mimo relay network with hybrid processing"
    - "throughput analysis of massive mimo uplink with low resolution adcs"
    - "base station selection for massive mimo networks with two stage precoding"

Connected through hyperedge HE-8 (induced by source paper "alternating iterative secure structure between beamforming and power allocation for uav aided directional modulation networks"):
  with members:
    - "robust secure transmission of using main lobe integration based leakage beamforming in directional modulation mu mimo systems"
    - "secure transmission with large numbers of antennas and finite alphabet inputs"
    - "joint trajectory and communication design for multi uav enabled wireless networks"
    - "artificial noise aided secure multicast precoding for directional modulation systems"
    - "low complexity and high resolution doa estimation for hybrid analog and digital massive mimo receive array"
    - "overcoming endurance issue uav enabled communications with proactive caching"
    - "energy efficient uav communication with trajectory optimization"
    - "artificial noise aided secure transmission with directional modulation based on random frequency diverse arrays"

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)