human: Given a hyperedge-centered hypergraph: <hypergraph>, where the center hyperedge is induced by one source paper and its member nodes are the cited papers.

Details of the hypergraph:
Center hyperedge (induced by source paper "joint power allocation and beamforming for energy efficient two way multi relay communications"):
  Abstract: This paper considers the joint design of user power allocation and relay beamforming in relaying communications, in which multiple pairs of single-antenna users exchange information with each other via multiple-antenna relays in two time slots. All users transmit their signals to the relays in the first time slot while the relays broadcast the beamformed signals to all users in the second time slot. The aim is to maximize the system's energy efficiency (EE) subject to quality-of-service (QoS) constraints in terms of exchange throughput requirements. The QoS constraints are nonconvex with many nonlinear cross-terms, so finding a feasible point is already computationally challenging. The sum throughput appears in the numerator while the total consumption power appears in the denominator of the EE objective function. The former is a nonconcave function and the latter is a nonconvex function, making fractional programming useless for EE optimization. Nevertheless, efficient iterations of low complexity to obtain its optimized solutions are developed. The performances of the multiple-user and multiple-relay networks under various scenarios are evaluated to show the merit of the paper development.

Includes members:
  Member "energy efficient power control a look at 5g wireless technologies":
    also connected through other hyperedges:
      - Hyperedge HE-1 (induced by source paper "energy efficiency optimization for downlink massive mimo with statistical csit")
  Member "a survey of energy efficient techniques for 5g networks and challenges ahead":
    also connected through other hyperedges:
      - Hyperedge HE-2 (induced by source paper "5g network slicing using sdn and nfv a survey of taxonomy architectures and future challenges")
  Member "a survey on device to device communication in cellular networks":
    also connected through other hyperedges:
      - Hyperedge HE-3 (induced by source paper "simultaneous energy harvesting and information transmission in a mimo full duplex system a machine learning based design")
  Member "multiobjective signal processing optimization the way to balance conflicting metrics in 5g systems":
    also connected through other hyperedges:
      - Hyperedge HE-4 (induced by source paper "joint dynamic pricing and radio resource allocation framework for iot services")
  Member "linear precoding designs for amplify and forward multiuser two way relay systems":
    also connected through other hyperedges:
      - Hyperedge HE-5 (induced by source paper "a survey on mimo transmission with discrete input signals technical challenges advances and future trends")
  Member "sum rate maximization in two way af mimo relaying polynomial time solutions to a class of dc programming problems":
    also connected through other hyperedges:
      - Hyperedge HE-6 (induced by source paper "joint beamforming and power allocation in downlink noma multiuser mimo networks")
  Member "on design of collaborative beamforming for two way relay networks":
    also connected through other hyperedges:
      - Hyperedge HE-7 (induced by source paper "low latency multiuser two way wireless relaying for spectral and energy efficiencies")
  Member "optimal beamforming for two way multi antenna relay channel with analogue network coding":
    also connected through other hyperedges:
      - Hyperedge HE-8 (induced by source paper "optimization of a power splitting protocol for two way multiple energy harvesting relay system")

Question: Please tell me which class the source paper 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)