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: "joint subcarrier pairing and power allocation for ofdm transmission with decode and forward relaying"
  Abstract: In this paper, a point-to-point orthogonal-frequency- division multiplexing (OFDM) system with a decode-and- forward (DF) relay is considered. The transmission consists of two hops. The source transmits in the first hop, and the relay transmits in the second hop. Each hop occupies one time slot. The relay is half-duplex, and capable of decoding the message on a particular subcarrier in one time slot, and re-encoding and forwarding it on a different subcarrier in the next time slot. Thus, each message is transmitted on a pair of subcarriers in two hops. It is assumed that the destination is capable of combining the signals from the source and the relay pertaining to the same message. The goal is to maximize the weighted sum rate of the system by jointly optimizing subcarrier pairing and power allocation on each subcarrier in each hop. The weighting of the rates is to take into account the fact that different subcarriers may carry signals for different services. Both total and individual power constraints for the source and the relay are investigated. For the situations where the relay does not transmit on some subcarriers because doing so does not improve the weighted sum rate, we further allow the source to transmit new messages on these idle subcarriers. To the best of our knowledge, such a joint optimization inclusive of the destination combining has not been discussed in the literature. The problem is first formulated as a mixed integer programming problem. It is then transformed to a convex optimization problem by continuous relaxation, and solved in the dual domain. Based on the optimization results, algorithms to achieve feasible solutions are also proposed. Simulation results show that the proposed algorithms almost achieve the optimal weighted sum rate and outperform the existing methods in various channel conditions.

Connected through hyperedge HE-1 (induced by source paper "subcarrier pairing as channel gain tailoring joint resource allocation for relay assisted secure ofdma with untrusted users"):
  with members:
    - "jammer assisted resource allocation in secure ofdma with untrusted users"
    - "utility regions for df relay in ofdma based secure communication with untrusted users"
    - "ofdma based df secure cooperative communication with untrusted users"
    - "secure communications in noma system subcarrier assignment and power allocation"
    - "principles of physical layer security in multiuser wireless networks a survey"
    - "on the complexity of joint subcarrier and power allocation for multi user ofdma systems"
    - "power and subcarrier allocation for physical layer security in ofdma based broadband wireless networks"

Connected through hyperedge HE-2 (induced by source paper "a multiband ofdma heterogeneous network for millimeter wave 5g wireless applications"):
  with members:
    - "hybrid millimeter wave systems a novel paradigm for hetnets"
    - "coverage and rate analysis for millimeter wave cellular networks"
    - "what will 5g be"

Connected through hyperedge HE-3 (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-4 (induced by source paper "weighted sum rate maximization for downlink ofdma with subcarrier pair based opportunistic df relaying"):
  with members:
    - "power minimization for ofdm transmission with subcarrier pair based opportunistic df relaying"
    - "on the scale algorithm for multiuser multicarrier power spectrum management"
    - "wsr maximized resource allocation in multiple df relays aided ofdma downlink transmission"
    - "sum rate maximized resource allocation in multiple df relays aided ofdm transmission"
    - "optimization framework and graph based approach for relay assisted bidirectional ofdma cellular networks"

Connected through hyperedge HE-5 (induced by source paper "novel subcarrier pair based opportunistic df protocol for cooperative downlink ofdma"):
  with members:
    - "weighted sum rate maximization for downlink ofdma with subcarrier pair based opportunistic df relaying"
    - "power minimization for ofdm transmission with subcarrier pair based opportunistic df relaying"
    - "wsr maximized resource allocation in multiple df relays aided ofdma downlink transmission"
    - "sum rate maximized resource allocation in multiple df relays aided ofdm transmission"

Connected through hyperedge HE-6 (induced by source paper "jointly optimal channel and power assignment for dual hop multi channel multi user relaying"):
  with members:
    - "jointly optimal channel pairing and power allocation for multichannel multihop relaying"
    - "optimization framework and graph based approach for relay assisted bidirectional ofdma cellular networks"
    - "distributive subband allocation power and rate control for relay assisted ofdma cellular system with imperfect system state knowledge"

Connected through hyperedge HE-7 (induced by source paper "optimal power allocation for two way decode and forward ofdm relay networks"):
  with members:
    - "optimal real time spectrum sharing between cooperative relay and ad hoc networks"
    - "resource allocation for wireless fading relay channels max min solution"

Connected through hyperedge HE-8 (induced by source paper "resource allocation with subcarrier pairing in ofdma two way relay networks"):
  with members:
    - "optimization framework and graph based approach for relay assisted bidirectional ofdma cellular 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)