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: "qos aware transmission policies for ofdm bidirectional decode and forward relaying"
  Abstract: Two-way relaying can considerably improve spectral efficiency in relay-assisted bidirectional communications. However, the benefits and flexible structure of orthogonal frequency division multiplexing (OFDM)-based two-way decode-and-forward (DF) relay systems is much less exploited. Moreover, most of existing works have not considered quality-of-service (QoS) provisioning for two-way relaying. In this paper, we consider the OFDM-based bidirectional transmission where a pair of users exchange information with or without the assistance of a single DF relay. Each user can communicate with the other via three transmission modes: direct transmission, one-way relaying, and two-way relaying. We jointly optimize the transmission policies, including power allocation, transmission mode selection, and subcarrier assignment for maximizing the weighted sum rates of the two users with diverse quality-of-service (QoS) guarantees. We formulate the joint optimization problem as a mixed integer programming problem. By using the dual method, we efficiently solve the problem in an asymptotically optimal manner. Moreover, we derive the capacity region of two-way DF relaying in parallel channels. Simulation results show that the proposed resource-allocation scheme can substantially improve system performance compared with the conventional schemes. A number of interesting insights are also provided via comprehensive simulations.

Connected through hyperedge HE-1 (induced by source paper "joint uplink and downlink transmissions in user centric ofdma cloud ran"):
  with members:
    - "joint precoding and rrh selection for user centric green mimo c ran"
    - "fronthaul limited uplink ofdma in ultra dense cran with hybrid decoding"
    - "joint millimeter wave fronthaul and ofdma resource allocation in ultra dense cran"
    - "green ofdma resource allocation in cache enabled cran"
    - "why to decouple the uplink and downlink in cellular networks and how to do it"
    - "fronthaul constrained cloud radio access networks insights and challenges"
    - "coordinated scheduling for the downlink of cloud radio access networks"
    - "what will 5g be"

Connected through hyperedge HE-2 (induced by source paper "charge then forward wireless powered communication for multiuser relay networks"):
  with members:
    - "joint power allocation and beamforming for energy efficient two way multi relay communications"
    - "power allocation for secure swipt systems with wireless powered cooperative jamming"
    - "capacity of the two hop relay channel with wireless energy transfer from relay to source and energy transmission cost"
    - "multipair two way relay network with harvest then transmit users resolving pairwise uplink downlink coupling"
    - "artificial noise aided secrecy information and power transfer in ofdma systems"
    - "wireless powered communication opportunities and challenges"
    - "wireless powered relays in cooperative communications time switching relaying protocols and throughput analysis"
    - "harvest then cooperate wireless powered cooperative communications"

Connected through hyperedge HE-3 (induced by source paper "joint resource allocation in swipt based multi antenna decode and forward relay networks"):
  with members:
    - "power allocation for secure swipt systems with wireless powered cooperative jamming"
    - "relaying strategies for wireless powered mimo relay networks"
    - "distributed power splitting for swipt in relay interference channels using game theory"
    - "joint wireless information and power transfer for an autonomous multiple antenna relay system"
    - "information and energy cooperation in ofdm relaying protocols and optimization"
    - "joint power splitting and antenna selection in energy harvesting relay channels"
    - "energy harvesting for physical layer security in ofdma networks"
    - "enhancing wireless information and power transfer by exploiting multi antenna techniques"

Connected through hyperedge HE-4 (induced by source paper "information and energy cooperation in ofdm relaying protocols and optimization"):
  with members:
    - "secrecy wireless information and power transfer in ofdma systems"
    - "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"
    - "power allocation strategies in energy harvesting wireless cooperative networks"
    - "wireless information and power transfer with full duplex relaying"
    - "energy cooperation in energy harvesting communications"
    - "simultaneous information and power transfer for broadband wireless systems"
    - "wireless information and power transfer in multiuser ofdm systems"

Connected through hyperedge HE-5 (induced by source paper "energy harvesting for physical layer security in ofdma networks"):
  with members:
    - "secrecy wireless information and power transfer in fading wiretap channel"
    - "information and energy cooperation in ofdm relaying protocols and optimization"
    - "robust beamforming for secure communication in systems with wireless information and power transfer"
    - "secrecy wireless information and power transfer with miso beamforming"
    - "spatially selective artificial noise aided transmit optimization for miso multi eves secrecy rate maximization"
    - "simultaneous information and power transfer for broadband wireless systems"
    - "wireless information and power transfer in multiuser ofdm systems"
    - "wireless information and power transfer a dynamic power splitting approach"

Connected through hyperedge HE-6 (induced by source paper "energy harvesting for secure ofdma systems"):
  with members:
    - "simultaneous information and power transfer for broadband wireless systems"
    - "wireless information and power transfer in multiuser ofdm systems"
    - "wireless information and power transfer energy efficiency optimization in ofdma systems"
    - "wireless information and power transfer a dynamic power splitting approach"
    - "wireless information transfer with opportunistic energy harvesting"
    - "on the transfer of information and energy in multi user systems"
    - "resource allocation with subcarrier pairing in ofdma two way relay networks"
    - "power and subcarrier allocation for physical layer security in ofdma based broadband wireless networks"

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)