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: "optimal beamforming for two way multi antenna relay channel with analogue network coding"
  Abstract: This paper studies the wireless two-way relay channel (TWRC), where two source nodes, S1 and S2, exchange information through an assisting relay node, R. It is assumed that R receives the sum signal from S1 and S2 in one time-slot, and then amplifies and forwards the received signal to both S1 and S2 in the next time-slot. By applying the principle of analogue network (ANC), each of S1 and S2 cancels the so-called "self-interference" in the received signal from R and then decodes the desired message. Assuming that S1 and S2 are each equipped with a single antenna and R with multi-antennas, this paper analyzes the capacity region of an ANC-based TWRC with linear processing (beamforming) at R. The capacity region contains all the achievable bidirectional rate-pairs of S1 and S2 under the given transmit power constraints at S1, S2, and R. We present the optimal relay beamforming structure as well as an efficient algorithm to compute the optimal beamforming matrix based on convex optimization techniques. Low-complexity suboptimal relay beamforming schemes are also presented, and their achievable rates are compared against the capacity with the optimal scheme.

Connected through hyperedge HE-1 (induced by source paper "optimization of a power splitting protocol for two way multiple energy harvesting relay system"):
  with members:
    - "rf based energy harvesting in decode and forward relaying systems ergodic and outage capacities"
    - "throughput maximization for two way relay channels with energy harvesting nodes the impact of relaying strategies"
    - "wireless powered relays in cooperative communications time switching relaying protocols and throughput analysis"
    - "energy harvesting wireless communications a review of recent advances"
    - "secure communication via a wireless energy harvesting untrusted relay"
    - "outage analysis of cooperative transmission with energy harvesting relay time switching vs power splitting"
    - "joint resource optimization for multicell networks with wireless energy harvesting relays"
    - "wireless networks with rf energy harvesting a contemporary survey"

Connected through hyperedge HE-2 (induced by source paper "low latency multiuser two way wireless relaying for spectral and energy efficiencies"):
  with members:
    - "joint power allocation and beamforming for energy efficient two way multi relay communications"
    - "overview of full dimension mimo in lte advanced pro"
    - "energy efficient power control a look at 5g wireless technologies"
    - "a survey of energy efficient techniques for 5g networks and challenges ahead"
    - "passive self interference suppression for full duplex infrastructure nodes"
    - "analysis of oscillator phase noise effects on self interference cancellation in full duplex ofdm radio transceivers"
    - "on design of collaborative beamforming for two way relay networks"

Connected through hyperedge HE-3 (induced by source paper "joint power allocation and beamforming for energy efficient two way multi relay communications"):
  with members:
    - "energy efficient power control a look at 5g wireless technologies"
    - "a survey of energy efficient techniques for 5g networks and challenges ahead"
    - "a survey on device to device communication in cellular networks"
    - "multiobjective signal processing optimization the way to balance conflicting metrics in 5g systems"
    - "linear precoding designs for amplify and forward multiuser two way relay systems"
    - "sum rate maximization in two way af mimo relaying polynomial time solutions to a class of dc programming problems"
    - "on design of collaborative beamforming for two way relay networks"

Connected through hyperedge HE-4 (induced by source paper "sum secrecy rate maximization for full duplex two way relay networks using alamouti based rank two beamforming"):
  with members:
    - "multi objective optimization for robust power efficient and secure full duplex wireless communication systems"
    - "joint beamforming optimization and power control for full duplex mimo two way relay channel"
    - "optimal resource allocation in full duplex wireless powered communication network"
    - "simultaneous wireless information and power transfer in modern communication systems"
    - "full duplex wireless powered relay with self energy recycling"
    - "full duplex wireless powered communication network with energy causality"
    - "wireless information and power transfer with full duplex relaying"
    - "physical layer multicasting by stochastic transmit beamforming and alamouti space time coding"

Connected through hyperedge HE-5 (induced by source paper "multipair two way half duplex relaying with massive arrays and imperfect csi"):
  with members:
    - "performance analysis and scaling law of mrc mrt relaying with csi error in massive mimo systems"
    - "multipair full duplex relaying with massive arrays and linear processing"
    - "massive mimo with optimal power and training duration allocation"
    - "massive mimo for next generation wireless systems"
    - "multi pair amplify and forward relaying with very large antenna arrays"
    - "scaling up mimo opportunities and challenges with very large arrays"
    - "relay selection and resource allocation for two way df af cognitive radio networks"
    - "energy and spectral efficiency of very large multiuser mimo systems"

Connected through hyperedge HE-6 (induced by source paper "to harvest and jam a paradigm of self sustaining friendly jammers for secure af relaying"):
  with members:
    - "secrecy wireless information and power transfer in fading wiretap channel"
    - "multipair full duplex relaying with massive arrays and linear processing"
    - "robust beamforming for secure communication in systems with wireless information and power transfer"
    - "secrecy wireless information and power transfer with miso beamforming"
    - "multiuser miso beamforming for simultaneous wireless information and power transfer"
    - "secure communication with a wireless powered friendly jammer"
    - "throughput maximization in wireless powered communication networks"
    - "wireless physical layer security with imperfect channel state information a survey"

Connected through hyperedge HE-7 (induced by source paper "robust mimo harvest and jam helpers and relaying for secret communications"):
  with members:
    - "secrecy wireless information and power transfer in fading wiretap channel"
    - "multipair full duplex relaying with massive arrays and linear processing"
    - "robust beamforming for secure communication in systems with wireless information and power transfer"
    - "secrecy wireless information and power transfer with miso beamforming"
    - "multiuser miso beamforming for simultaneous wireless information and power transfer"
    - "throughput maximization in wireless powered communication networks"
    - "wireless physical layer security with imperfect channel state information a survey"
    - "wireless information transfer with opportunistic energy harvesting"

Connected through hyperedge HE-8 (induced by source paper "joint beamforming optimization and power control for full duplex mimo two way relay channel"):
  with members:
    - "passive self interference suppression for full duplex infrastructure nodes"
    - "low complexity end to end performance optimization in mimo full duplex relay systems"
    - "practical full duplex physical layer network coding"
    - "in band full duplex wireless challenges and opportunities"
    - "experiment driven characterization of full duplex wireless systems"
    - "on cooperative relaying schemes for wireless physical layer security"

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)