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: "cooperative multi cell block diagonalization with per base station power constraints"
  Abstract: Block diagonalization (BD) is a practical linear precoding technique that eliminates the inter-user interference in downlink multiuser multiple-input multiple-output (MIMO) systems. In this paper, we apply BD to the downlink transmission in a cooperative multi-cell MIMO system, where the signals from different base stations (BSs) to all the mobile stations (MSs) are jointly designed with the perfect knowledge of the downlink channels and transmit messages. Specifically, we study the optimal BD precoder design to maximize the weighted sum-rate of all the MSs subject to a set of per-BS power constraints. This design problem is formulated in an auxiliary MIMO broadcast channel (BC) with a set of transmit power constraints corresponding to those for individual BSs in the multi-cell system. By applying convex optimization techniques, this paper develops an efficient algorithm to solve this problem, and derives the closed-form expression for the optimal BD precoding matrix. It is revealed that the optimal BD precoding vectors for each MS in the per-BS power constraint case are in general non-orthogonal, which differs from the conventional orthogonal BD precoder design for the MIMO-BC under one single sum-power constraint. Moreover, for the special case of single-antenna BSs and MSs, the proposed solution reduces to the optimal zero-forcing beamforming (ZF-BF) precoder design for the weighted sum-rate maximization in the multiple-input single-output (MISO) BC with per-antenna power constraints. Suboptimal and low-complexity BD/ZF-BF precoding schemes are also presented, and their achievable rates are compared against those with the optimal schemes.

Connected through hyperedge HE-1 (induced by source paper "cooperative downlink interference transmission and cancellation for cellular connected uav a divide and conquer approach"):
  with members:
    - "uav communications for 5g and beyond recent advances and future trends"
    - "cognitive uav communication via joint maneuver and power control"
    - "understanding uav cellular communications from existing networks to massive mimo"
    - "beyond 5g with uavs foundations of a 3d wireless cellular network"
    - "cellular connected uav uplink association power control and interference coordination"
    - "multi beam uav communication in cellular uplink cooperative interference cancellation and sum rate maximization"
    - "the sky is not the limit lte for unmanned aerial vehicles"
    - "interference mitigation methods for unmanned aerial vehicles served by cellular networks"

Connected through hyperedge HE-2 (induced by source paper "group sparse precoding for cloud ran with multiple user antennas"):
  with members:
    - "joint precoding and rrh selection for user centric green mimo c ran"
    - "energy efficiency of downlink transmission strategies for cloud radio access networks"
    - "a survey of sparse representation algorithms and applications"
    - "robust group sparse beamforming for multicast green cloud ran with imperfect csi"
    - "large scale convex optimization for ultra dense cloud ran"
    - "a comparative study of downlink mimo cellular networks with co located and distributed base station antennas"
    - "sparse beamforming and user centric clustering for downlink cloud radio access network"
    - "group sparse beamforming for green cloud ran"

Connected through hyperedge HE-3 (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"
    - "exploiting multi antennas for opportunistic spectrum sharing in cognitive radio networks"
    - "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-4 (induced by source paper "optimizing df cognitive radio networks with full duplex enabled energy access points"):
  with members:
    - "robust resource allocation for mimo wireless powered communication networks based on a non linear eh model"
    - "wireless powered communication networks an overview"
    - "practical non linear energy harvesting model and resource allocation for swipt systems"
    - "cognitive wireless powered network spectrum sharing models and throughput maximization"
    - "wireless powered cooperative jamming for secrecy multi af relaying networks"
    - "comp meets smart grid a new communication and energy cooperation paradigm"
    - "energy efficient resource allocation for wireless powered communication networks"
    - "joint resource optimization for multicell networks with wireless energy harvesting relays"

Connected through hyperedge HE-5 (induced by source paper "a stochastic analysis of network mimo systems"):
  with members:
    - "large scale mimo versus network mimo for multicell interference mitigation"
    - "adaptive multicell 3d beamforming in multi antenna cellular networks"
    - "a tractable model for noncoherent joint transmission base station cooperation"
    - "optimizing multi cell massive mimo for spectral efficiency how many users should be scheduled"
    - "analysis of joint transmit receive diversity in downlink mimo heterogeneous cellular networks"
    - "a stochastic geometry analysis of inter cell interference coordination and intra cell diversity"
    - "downlink mimo hetnets modeling ordering results and performance analysis"
    - "downlink multi antenna heterogeneous cellular network with load balancing"

Connected through hyperedge HE-6 (induced by source paper "joint optimization of power and data transfer in multiuser mimo systems"):
  with members:
    - "wireless powered communication opportunities and challenges"
    - "practical non linear energy harvesting model and resource allocation for swipt systems"
    - "wireless networks with rf energy harvesting a contemporary survey"
    - "secure beamforming for mimo broadcasting with wireless information and power transfer"
    - "decomposition by partial linearization parallel optimization of multi agent systems"
    - "multiuser miso beamforming for simultaneous wireless information and power transfer"
    - "joint transmit beamforming and receive power splitting for miso swipt systems"
    - "application of smart antenna technologies in simultaneous wireless information and power transfer"

Connected through hyperedge HE-7 (induced by source paper "constant envelope precoding for mimo systems"):
  with members:
    - "constant envelope precoding with adaptive receiver constellation in miso fading channel"
    - "constant envelope precoding with time variation constraint on the transmitted phase angles"
    - "designing unimodular codes via quadratic optimization"
    - "constant envelope multi user precoding for frequency selective massive mimo systems"
    - "per antenna constant envelope precoding for large multi user mimo systems"
    - "single user beamforming in large scale miso systems with per antenna constant envelope constraints the doughnut channel"
    - "on gaussian mimo bc mac duality with multiple transmit covariance constraints"

Connected through hyperedge HE-8 (induced by source paper "mse based precoding for mimo downlinks in heterogeneous networks"):
  with members:
    - "what will 5g be"
    - "joint source and relay precoding designs for mimo two way relaying based on mse criterion"
    - "linear precoding designs for amplify and forward multiuser two way relay systems"
    - "decomposition by successive convex approximation a unifying approach for linear transceiver design in heterogeneous networks"
    - "pilot contamination and precoding in multi cell tdd systems"

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)