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: "exploiting multi antennas for opportunistic spectrum sharing in cognitive radio networks"
  Abstract: In cognitive radio (CR) networks, there are scenarios where the secondary (lower priority) users intend to communicate with each other by opportunistically utilizing the transmit spectrum originally allocated to the existing primary (higher priority) users. For such a scenario, a secondary user usually has to tradeoff between two conflicting goals at the same time: one is to maximize its own transmit throughput; and the other is to minimize the amount of interference it produces at each primary receiver. In this paper, we study this fundamental tradeoff from an information-theoretic perspective by characterizing the secondary user's channel capacity under both its own transmit-power constraint as well as a set of interference-power constraints each imposed at one of the primary receivers. In particular, this paper exploits multi-antennas at the secondary transmitter to effectively balance between spatial multiplexing for the secondary transmission and interference avoidance at the primary receivers. Convex optimization techniques are used to design algorithms for the optimal secondary transmit spatial spectrum that achieves the capacity of the secondary transmission. Suboptimal solutions for ease of implementation are also presented and their performances are compared with the optimal solution. Furthermore, algorithms developed for the single-channel transmission are also extended to the case of multichannel transmission whereby the secondary user is able to achieve opportunistic spectrum sharing via transmit adaptations not only in space, but in time and frequency domains as well. Simulation results show that even under stringent interference-power constraints, substantial capacity gains are achievable for the secondary transmission by employing multi-antennas at the secondary transmitter. This is true even when the number of primary receivers exceeds that of secondary transmit antennas in a CR network, where an interesting "interference diversity" effect can be exploited.

Connected through hyperedge HE-1 (induced by source paper "optimal precoder designs for sum utility maximization in swipt enabled multi user mimo cognitive radio networks"):
  with members:
    - "joint optimization of power and data transfer in multiuser mimo systems"
    - "wireless powered communication opportunities and challenges"
    - "practical non linear energy harvesting model and resource allocation for swipt systems"
    - "throughput optimization for massive mimo systems powered by wireless energy transfer"
    - "mimo broadcasting for simultaneous wireless information and power transfer weighted mmse approaches"
    - "wireless networks with rf energy harvesting a contemporary survey"
    - "multiuser miso beamforming for simultaneous wireless information and power transfer"
    - "mimo broadcasting for simultaneous wireless information and power transfer"

Connected through hyperedge HE-2 (induced by source paper "context aware decentralized invariant signaling for opportunistic communications"):
  with members:
    - "state of the art taxonomy and open issues on cognitive radio networks with noma"
    - "resource allocation and fairness in wireless powered cooperative cognitive radio networks"
    - "covariance based ofdm spectrum sensing with sub nyquist samples"
    - "vandermonde subspace frequency division multiplexing for two tiered cognitive radio networks"
    - "distributed optimal beamformers for cognitive radios robust to channel uncertainties"
    - "enhanced intercell interference coordination challenges in heterogeneous networks"

Connected through hyperedge HE-3 (induced by source paper "multi beam uav communication in cellular uplink cooperative interference cancellation and sum rate maximization"):
  with members:
    - "mobile networks connected drones field trials simulations and design insights"
    - "the sky is not the limit lte for unmanned aerial vehicles"
    - "cellular enabled uav communication a connectivity constrained trajectory optimization perspective"
    - "massive mimo for communications with drone swarms"
    - "massive mimo for drone communications applications case studies and future directions"
    - "a survey on non orthogonal multiple access for 5g networks research challenges and future trends"
    - "coexistence of terrestrial and aerial users in cellular networks"
    - "cloud radio access network virtualizing wireless access for dense heterogeneous systems"

Connected through hyperedge HE-4 (induced by source paper "energy efficiency in mimo underlay and overlay device to device communications and cognitive radio systems"):
  with members:
    - "energy efficient power control a look at 5g wireless technologies"
    - "energy efficiency and sum rate when massive mimo meets device to device communication"
    - "energy efficient resource allocation for device to device underlay communication"
    - "dynamic power control for delay aware device to device communications"
    - "resource allocation under channel uncertainties for relay aided device to device communication underlaying lte a cellular networks"
    - "energy efficiency and spectral efficiency tradeoff in device to device d2d communications"
    - "designing multi user mimo for energy efficiency when is massive mimo the answer"
    - "cognitive beamforming for multiple secondary data streams with individual snr constraints"

Connected through hyperedge HE-5 (induced by source paper "opportunistic network decoupling with virtual full duplex operation in multi source interfering relay networks"):
  with members:
    - "on the degrees of freedom of the large scale interfering two way relay network"
    - "codebook based opportunistic interference alignment"
    - "real interference alignment exploiting the potential of single antenna systems"
    - "opportunistic downlink interference alignment"
    - "parallel opportunistic routing in wireless networks"
    - "opportunistic interference alignment for mimo interfering multiple access channels"
    - "degrees of freedom of two hop wireless networks everyone gets the entire cake"
    - "opportunistic interference mitigation achieves optimal degrees of freedom in wireless multi cell uplink networks"

Connected through hyperedge HE-6 (induced by source paper "cooperative prediction and sensing based spectrum sharing in cognitive radio networks"):
  with members:
    - "an efficient precoder design for multiuser mimo cognitive radio networks with interference constraints"
    - "joint beamforming and antenna selection for sum rate maximization in cognitive radio networks"
    - "on the limits of predictability in real world radio spectrum state dynamics from entropy theory to 5g spectrum sharing"
    - "robust cooperative spectrum sensing scheduling optimization in multi channel dynamic spectrum access networks"
    - "primary user traffic classification in dynamic spectrum access networks"
    - "joint transmit beamforming and receive power splitting for miso swipt systems"
    - "robust secure transmission in miso channels based on worst case optimization"
    - "weighted sum rate optimization for cognitive radio mimo broadcast channels"

Connected through hyperedge HE-7 (induced by source paper "an efficient precoder design for multiuser mimo cognitive radio networks with interference constraints"):
  with members:
    - "collaborative relay beamforming for secrecy"
    - "beamforming and rate allocation in miso cognitive radio networks"
    - "cooperative multi cell block diagonalization with per base station power constraints"
    - "on peak versus average interference power constraints for protecting primary users in cognitive radio networks"
    - "weighted sum rate optimization for cognitive radio mimo broadcast channels"
    - "capacity limits of cognitive radio with distributed and dynamic spectral activity"

Connected through hyperedge HE-8 (induced by source paper "distributed energy efficient cross layer optimization for multihop mimo cognitive radio networks with primary user rate protection"):
  with members:
    - "database assisted distributed spectrum sharing"
    - "outage constrained robust transmit optimization for multiuser miso downlinks tractable approximations by conic optimization"
    - "dynamic resource allocation in cognitive radio networks"
    - "optimal spectrum sharing in mimo cognitive radio networks via semidefinite programming"
    - "cognitive mimo radio"

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)