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: "on the ergodic rate lower bounds with applications to massive mimo"
  Abstract: A well-known lower bound widely used in the massive MIMO literature hinges on channel hardening, i.e., the phenomenon for which, thanks to the large number of antennas, the effective channel coefficients resulting from beamforming tend to deterministic quantities. If the channel hardening effect does not hold sufficiently well, this bound may be quite far from the actual achievable rate. In recent developments of massive MIMO, several scenarios where channel hardening is not sufficiently pronounced have emerged. These settings include, for example, the case of small scattering angular spread, yielding highly correlated channel vectors, and the case of cell-free massive MIMO. In this short contribution, we present two new bounds on the achievable ergodic rate that offer a complementary behavior with respect to the classical bound: while the former performs well in the case of channel hardening and/or when the system is interference-limited (notably, in the case of finite number of antennas and conjugate beamforming transmission), the new bounds perform well when the useful signal coefficient does not harden but the channel coherence block length is large with respect to the number of users, and in the case where interference is nearly entirely eliminated by zero-forcing beamforming. Overall, using the most appropriate bound depending on the system operating conditions yields a better understanding of the actual performance of systems where channel hardening may not occur, even in the presence of a very large number of antennas.

Connected through hyperedge HE-1 (induced by source paper "analysis of uav communications in cell free massive mimo systems"):
  with members:
    - "scalability aspects of cell free massive mimo"
    - "max min rate of cell free massive mimo uplink with optimal uniform quantization"
    - "ubiquitous cell free massive mimo communications"
    - "cellular uav to uav communications"
    - "making cell free massive mimo competitive with mmse processing and centralized implementation"
    - "understanding uav cellular communications from existing networks to massive mimo"
    - "tutorial on uav a blue sky view on wireless communication"
    - "cellular connected uav uplink association power control and interference coordination"

Connected through hyperedge HE-2 (induced by source paper "joint user selection power allocation and precoding design with imperfect csit for multi cell mu mimo downlink systems"):
  with members:
    - "optimal pilot and payload power control in single cell massive mimo systems"
    - "on the capacity of cloud radio access networks with oblivious relaying"
    - "massive mimo with imperfect channel covariance information"
    - "sum rate maximization for linearly precoded downlink multiuser miso systems with partial csit a rate splitting approach"
    - "robust transmission in downlink multiuser miso systems a rate splitting approach"
    - "cell free massive mimo versus small cells"
    - "a rate splitting strategy for massive mimo with imperfect csit"
    - "limited feedback hybrid precoding for multi user millimeter wave systems"

Connected through hyperedge HE-3 (induced by source paper "enabling uav communications with cell free massive mimo"):
  with members:
    - "ubiquitous cell free massive mimo communications"
    - "making cell free massive mimo competitive with mmse processing and centralized implementation"
    - "understanding uav cellular communications from existing networks to massive mimo"
    - "supporting uav cellular communications through massive mimo"
    - "the essential guide to realizing 5g connected uavs with massive mimo"
    - "the sky is not the limit lte for unmanned aerial vehicles"
    - "downlink performance of uplink fractional power control in 5g massive mimo systems"
    - "a tutorial on uavs for wireless networks applications challenges and open problems"

Connected through hyperedge HE-4 (induced by source paper "balance queueing and retransmission latency optimal massive mimo design"):
  with members:
    - "delay performance of the multiuser miso downlink under imperfect csi and finite length coding"
    - "outage of periodic downlink wireless networks with hard deadlines"
    - "massive mimo has unlimited capacity"
    - "delay performance of miso wireless communications"
    - "massive mimo ten myths and one critical question"
    - "massive mimo performance evaluation based on measured propagation data"
    - "on noisy arq in block fading channels"
    - "massive mimo for next generation wireless systems"

Connected through hyperedge HE-5 (induced by source paper "joint transmit and circuit power minimization in massive mimo with downlink sinr constraints when to turn on massive mimo"):
  with members:
    - "employing antenna selection to improve energy efficiency in massive mimo systems"
    - "massive mimo ten myths and one critical question"
    - "energy efficiency in massive mimo based 5g networks opportunities and challenges"
    - "energy efficiency of massive mimo coping with daily load variation"
    - "massive mimo performance evaluation based on measured propagation data"
    - "impact of transceiver power consumption on the energy efficiency of zero forcing detector in massive mimo systems"
    - "what will 5g be"
    - "optimal design of energy efficient multi user mimo systems is massive mimo the answer"

Connected through hyperedge HE-6 (induced by source paper "downlink training in cell free massive mimo a blessing in disguise"):
  with members:
    - "ubiquitous cell free massive mimo communications"
    - "on the total energy efficiency of cell free massive mimo"
    - "channel hardening and favorable propagation in cell free massive mimo with stochastic geometry"
    - "cell free massive mimo versus small cells"
    - "how much do downlink pilots improve cell free massive mimo"
    - "no downlink pilots are needed in tdd massive mimo"
    - "massive mimo ten myths and one critical question"
    - "power scaling of uplink massive mimo systems with arbitrary rank channel means"

Connected through hyperedge HE-7 (induced by source paper "what role can noma play in massive mimo"):
  with members:
    - "exploiting multiple antenna techniques for non orthogonal multiple access"
    - "performance analysis of noma in training based multiuser mimo systems"
    - "joint power allocation and beamforming for non orthogonal multiple access noma in 5g millimeter wave communications"
    - "a survey on non orthogonal multiple access for 5g networks research challenges and future trends"
    - "design of massive mimo noma with limited feedback"
    - "no downlink pilots are needed in tdd massive mimo"
    - "aspects of favorable propagation in massive mimo"
    - "massive mimo for next generation wireless systems"

Connected through hyperedge HE-8 (induced by source paper "mixed timescale beamforming and power splitting for massive mimo aided swipt iot network"):
  with members:
    - "two timescale hybrid compression and forward for massive mimo aided c ran"
    - "fractional programming for communication systems part ii uplink scheduling via matching"
    - "practical non linear energy harvesting model and resource allocation for swipt systems"
    - "joint transmit beamforming and receive power splitting for miso swipt systems"
    - "mimo broadcasting for simultaneous wireless information and power transfer"

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)