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: "transmission schemes based on sum rate analysis in distributed antenna systems"
  Abstract: In this paper, we study single cell multi-user downlink distributed antenna systems (DAS) where antenna ports are geographically separated in a cell. First, we derive an expression of the ergodic sum rate for the DAS in the presence of pathloss. Then, we propose a transmission selection scheme based on the derived expressions which does not require channel state information at the transmitter. Utilizing the knowledge of distance information from a user to each distributed antenna (DA) port, we consider the optimization of pairings of DA ports and users to maximize the system performance. Based on the ergodic sum rate expressions, the proposed scheme chooses the best mode maximizing the ergodic sum rate among mode candidates. In our proposed scheme, the number of mode candidates are greatly reduced compared to that of ideal mode selection. In addition, we analyze the signal to noise ratio cross-over point for different modes using the sum rate expressions. Through Monte Carlo simulations, we show the accuracy of our derivations for the ergodic sum rate. Moreover, simulation results with the pathloss modeling confirm that the proposed scheme produces the average sum rate identical to the ideal mode selection with significantly reduced candidates.

Connected through hyperedge HE-1 (induced by source paper "robust designs of beamforming and power splitting for distributed antenna systems with wireless energy harvesting"):
  with members:
    - "beamforming and power splitting designs for an aided secure multi user mimo swipt systems"
    - "some new research trends in wirelessly powered communications"
    - "robust beamforming for secure communication in systems with wireless information and power transfer"
    - "secure and green swipt in distributed antenna networks with limited backhaul capacity"
    - "joint transmit beamforming and receive power splitting for miso swipt systems"
    - "application of smart antenna technologies in simultaneous wireless information and power transfer"
    - "mimo broadcasting for simultaneous wireless information and power transfer"
    - "outage constrained robust transmit optimization for multiuser miso downlinks tractable approximations by conic optimization"

Connected through hyperedge HE-2 (induced by source paper "energy efficient swipt in iot distributed antenna systems"):
  with members:
    - "simultaneous wireless information and power transfer in cooperative relay networks with rateless codes"
    - "artificial noise aided secrecy information and power transfer in ofdma systems"
    - "training based swipt optimal power splitting at the receiver"
    - "energy efficient resource assignment and power allocation in heterogeneous cloud radio access networks"
    - "information and energy cooperation in ofdm relaying protocols and optimization"
    - "energy harvesting for physical layer security in ofdma networks"
    - "wireless information and energy transfer for two hop non regenerative mimo ofdm relay networks"
    - "secure and green swipt in distributed antenna networks with limited backhaul capacity"

Connected through hyperedge HE-3 (induced by source paper "noma in distributed antenna system for max min fairness and max sum rate"):
  with members:
    - "what will 5g be"
    - "on the performance of non orthogonal multiple access in 5g systems with randomly deployed users"

Connected through hyperedge HE-4 (induced by source paper "tradeoff caching strategy of outage probability and fronthaul usage in cloud ran"):
  with members:
    - "joint precoding and rrh selection for user centric green mimo c ran"
    - "cache enabled heterogeneous cellular networks optimal tier level content placement"
    - "content centric sparse multicast beamforming for cache enabled cloud ran"
    - "distributed edge caching scheme considering the tradeoff between the diversity and redundancy of cached content"
    - "redesigning fronthaul for next generation networks beyond baseband samples and point to point links"
    - "backhaul aware caching placement for wireless networks"
    - "content centric multicast beamforming in cache enabled cloud radio access networks"
    - "base station assisted device to device communications for high throughput wireless video networks"

Connected through hyperedge HE-5 (induced by source paper "energy efficiency optimization for mimo distributed antenna systems"):
  with members:
    - "totally distributed energy efficient transmission in mimo interference channels"
    - "energy efficiency optimization in relay assisted mimo systems with perfect and statistical csi"
    - "what will 5g be"
    - "energy efficiency optimization for mimo ofdm mobile multimedia communication systems with qos constraints"
    - "energy efficiency optimization for mimo broadcast channels"
    - "framework for link level energy efficiency optimization with informed transmitter"
    - "miso capacity with per antenna power constraint"
    - "cooperative interference management with miso beamforming"

Connected through hyperedge HE-6 (induced by source paper "energy efficient large scale distributed antenna system l das for multiple users"):
  with members:
    - "massive mimo systems with non ideal hardware energy efficiency estimation and capacity limits"
    - "spectral efficiency and energy efficiency of ofdm systems impact of power amplifiers and countermeasures"
    - "designing multi user mimo for energy efficiency when is massive mimo the answer"
    - "scaling up mimo opportunities and challenges with very large arrays"
    - "energy efficiency optimization for mimo broadcast channels"
    - "framework for link level energy efficiency optimization with informed transmitter"

Connected through hyperedge HE-7 (induced by source paper "asymptotic rate analysis of downlink multi user systems with co located and distributed antennas"):
  with members:
    - "scaling up mimo opportunities and challenges with very large arrays"
    - "on capacity of large scale mimo multiple access channels with distributed sets of correlated antennas"
    - "message passing algorithm for distributed downlink regularized zero forcing beamforming with cooperative base stations"

Connected through hyperedge HE-8 (induced by source paper "on the coexistence of macrocell spatial multiplexing and cognitive femtocells"):
  with members:
    - "modeling and analysis of k tier downlink heterogeneous cellular networks"
    - "open vs closed access femtocells in the uplink"
    - "femto macro cellular interference control with subband scheduling and interference cancelation"
    - "femtocell networks a survey"
    - "multiuser mimo achievable rates with downlink training and channel state feedback"

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)