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: "energy efficient joint unicast and multicast beamforming with multi antenna user terminals"
  Abstract: This paper studies energy-efficient joint transmit and receive beamforming in multi-cell multi-user multiple-input multiple-output systems. We consider conventional network energy efficiency metric where the users can receive unicasting streams in addition to the group-specific common multicasting streams which have certain rate constraints. The goal is to use the transmission resources more efficiently to improve the energy efficiency, when the users are equipped with multiple antennas. Numerical results show the achieved energy efficiency gains by using the additional degrees of freedom of the multicasting transmission to private message unicasting.

Connected through hyperedge HE-1 (induced by source paper "rate splitting for multi antenna non orthogonal unicast and multicast transmission spectral and energy efficiency analysis"):
  with members:
    - "energy efficiency of rate splitting multiple access and performance benefits over sdma and noma"
    - "rate splitting multiple access for coordinated multi point joint transmission"
    - "rate splitting for multi antenna non orthogonal unicast and multicast transmission"
    - "gaussian message passing for overloaded massive mimo noma"
    - "rate splitting multiple access for downlink communication systems bridging generalizing and outperforming sdma and noma"
    - "rate splitting for max min fair multigroup multicast beamforming in overloaded systems"
    - "optimal dof region of the k user miso bc with partial csit"
    - "generalized multicast multibeam precoding for satellite communications"

Connected through hyperedge HE-2 (induced by source paper "energy efficient multicell multigroup multicasting with joint beamforming and antenna selection"):
  with members:
    - "distributed optimization for coordinated beamforming in multicell multigroup multicast systems power minimization and sinr balancing"
    - "energy efficient beam coordination strategies with rate dependent processing power"
    - "conic quadratic formulations for wireless communications design"
    - "content centric sparse multicast beamforming for cache enabled cloud ran"
    - "multicast multigroup precoding and user scheduling for frame based satellite communications"
    - "weighted fair multicast multigroup beamforming under per antenna power constraints"
    - "optimal design of energy efficient multi user mimo systems is massive mimo the answer"
    - "coordinated multicast beamforming in multicell networks"

Connected through hyperedge HE-3 (induced by source paper "two layered superposition of broadcast multicast and unicast signals in multiuser ofdma systems"):
  with members:
    - "rate splitting for multi antenna non orthogonal unicast and multicast transmission"
    - "rate splitting for multi antenna non orthogonal unicast and multicast transmission spectral and energy efficiency analysis"
    - "a survey on non orthogonal multiple access for 5g networks research challenges and future trends"
    - "joint base station clustering and beamforming for non orthogonal multicast and unicast transmission with backhaul constraints"
    - "joint beamforming and broadcasting in massive mimo"
    - "on the spectral efficiency and security enhancements of noma assisted multicast unicast streaming"
    - "rate splitting for mimo wireless networks a promising phy layer strategy for lte evolution"
    - "on the performance of non orthogonal multiple access in 5g systems with randomly deployed users"

Connected through hyperedge HE-4 (induced by source paper "rate splitting for multi antenna non orthogonal unicast and multicast transmission"):
  with members:
    - "rate splitting multiple access for downlink communication systems bridging generalizing and outperforming sdma and noma"
    - "joint base station clustering and beamforming for non orthogonal multicast and unicast transmission with backhaul constraints"
    - "sum rate maximization for linearly precoded downlink multiuser miso systems with partial csit a rate splitting approach"
    - "rate splitting for mimo wireless networks a promising phy layer strategy for lte evolution"
    - "sum rate maximization for mu miso with partial csit using joint multicasting and broadcasting"

Connected through hyperedge HE-5 (induced by source paper "joint base station clustering and beamforming for non orthogonal multicast and unicast transmission with backhaul constraints"):
  with members:
    - "an efficient global algorithm for single group multicast beamforming"
    - "joint beamforming and broadcasting in massive mimo"
    - "robust transmission in downlink multiuser miso systems a rate splitting approach"
    - "rate splitting for mimo wireless networks a promising phy layer strategy for lte evolution"
    - "content centric sparse multicast beamforming for cache enabled cloud ran"
    - "sum rate maximization for mu miso with partial csit using joint multicasting and broadcasting"
    - "sparse beamforming and user centric clustering for downlink cloud radio access network"

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)