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: "uplink performance of time reversal mrc in massive mimo systems subject to phase noise"
  Abstract: Multiuser multiple-input–multiple-output (MIMO) cellular systems with an excess of base station (BS) antennas (Massive MIMO) offer unprecedented multiplexing gains and radiated energy efficiency. Oscillator phase noise is introduced in the transmitter and receiver radio frequency chains and severely degrades the performance of communication systems. We study the effect of oscillator phase noise in frequency-selective Massive MIMO systems with imperfect channel state information. In particular, we consider two distinct operation modes, namely, when the phase noise processes at the    $M$   BS antennas are identical (synchronous operation) and when they are independent (nonsynchronous operation) . We analyze a linear and low-complexity time-reversal maximum-ratio combining reception strategy. For both operation modes, we derive a lower bound on the sum-capacity, and we compare their performance. Based on the derived achievable sum-rates, we show that with the proposed receive processing, an    $O(\sqrt{M} ) $   array gain is achievable. Due to the phase noise drift, the estimated effective channel becomes progressively outdated. Therefore, phase noise effectively limits the length of the interval used for data transmission and the number of scheduled users. The derived achievable rates provide insights into the optimum choice of the data interval length and the number of scheduled users.

Connected through hyperedge HE-1 (induced by source paper "achieving phase coherency and gain stability in active antenna arrays for sub 6 ghz fdd and tdd fd mimo challenges and solutions"):
  with members:
    - "channel reciprocity calibration in tdd hybrid beamforming massive mimo systems"
    - "a framework for over the air reciprocity calibration for tdd massive mimo systems"
    - "toward a realistic assessment of multiple antenna hcns residual additive transceiver hardware impairments and channel aging"
    - "overview of full dimension mimo in lte advanced pro"
    - "massive mimo performance with imperfect channel reciprocity and channel estimation error"
    - "reciprocity calibration for massive mimo proposal modeling and validation"
    - "massive mimo with non ideal arbitrary arrays hardware scaling laws and circuit aware design"

Connected through hyperedge HE-2 (induced by source paper "massive mu mimo ofdm uplink with hardware impairments modeling and analysis"):
  with members:
    - "can hardware distortion correlation be neglected when analyzing uplink se in massive mimo"
    - "out of band radiation from antenna arrays clarified"
    - "throughput analysis of massive mimo uplink with low resolution adcs"
    - "channel estimation and performance analysis of one bit massive mimo systems"
    - "on out of band emissions of quantized precoding in massive mu mimo ofdm"
    - "impact of spatial filtering on distortion from low noise amplifiers in massive mimo base stations"
    - "linear precoding with low resolution dacs for massive mu mimo ofdm downlink"
    - "uplink performance of wideband massive mimo with one bit adcs"

Connected through hyperedge HE-3 (induced by source paper "rate splitting to mitigate residual transceiver hardware impairments in massive mimo systems"):
  with members:
    - "impact of general channel aging conditions on the downlink performance of massive mimo"
    - "energy efficiency in mimo underlay and overlay device to device communications and cognitive radio systems"
    - "sum rate maximization for linearly precoded downlink multiuser miso systems with partial csit a rate splitting approach"
    - "miso networks with imperfect csit a topological rate splitting approach"
    - "downlink mimo hcns with residual transceiver hardware impairments"
    - "robust transmission in downlink multiuser miso systems a rate splitting approach"
    - "a rate splitting strategy for max min fair multigroup multicasting"
    - "rate splitting for mimo wireless networks a promising phy layer strategy for lte evolution"

Connected through hyperedge HE-4 (induced by source paper "impact of general channel aging conditions on the downlink performance of massive mimo"):
  with members:
    - "massive mimo ten myths and one critical question"
    - "massive mimo 10 myths and one grand question"
    - "sum rate and power scaling of massive mimo systems with channel aging"
    - "impact of user mobility on optimal linear receivers in cellular networks"
    - "downlink performance of massive mimo under general channel aging conditions"
    - "uplink performance of conventional and massive mimo cellular systems with delayed csit"
    - "massive mimo with non ideal arbitrary arrays hardware scaling laws and circuit aware design"
    - "on the impact of oscillator phase noise on the uplink performance in a massive mimo ofdm system"

Connected through hyperedge HE-5 (induced by source paper "spatio temporal waveform design for multiuser massive mimo downlink with 1 bit receivers"):
  with members:
    - "capacity analysis of one bit quantized mimo systems with transmitter channel state information"
    - "massive mimo with non ideal arbitrary arrays hardware scaling laws and circuit aware design"
    - "linear precoding based on polynomial expansion large scale multi cell mimo systems"
    - "on the impact of hardware impairments on massive mimo"
    - "five disruptive technology directions for 5g"
    - "massive mu mimo downlink tdd systems with linear precoding and downlink pilots"
    - "scaling up mimo opportunities and challenges with very large arrays"
    - "constant envelope multi user precoding for frequency selective massive mimo systems"

Connected through hyperedge HE-6 (induced by source paper "mitigation of phase noise in massive mimo systems a rate splitting approach"):
  with members:
    - "impact of general channel aging conditions on the downlink performance of massive mimo"
    - "rate splitting to mitigate residual transceiver hardware impairments in massive mimo systems"
    - "rate splitting for mimo wireless networks a promising phy layer strategy for lte evolution"
    - "a rate splitting strategy for massive mimo with imperfect csit"
    - "rate analysis of two receiver miso broadcast channel with finite rate feedback a rate splitting approach"
    - "massive mimo with non ideal arbitrary arrays hardware scaling laws and circuit aware design"
    - "massive mimo multicasting in noncooperative cellular networks"
    - "scaling up mimo opportunities and challenges with very large arrays"

Connected through hyperedge HE-7 (induced by source paper "massive mimo performance with imperfect channel reciprocity and channel estimation error"):
  with members:
    - "performance analysis of massive mimo for cell boundary users"
    - "a novel antenna selection scheme for spatially correlated massive mimo uplinks with imperfect channel estimation"
    - "mmwave massive mimo based wireless backhaul for the 5g ultra dense network"
    - "massive mimo systems with non ideal hardware energy efficiency estimation and capacity limits"
    - "massive mimo for next generation wireless systems"
    - "downlink training techniques for fdd massive mimo systems open loop and closed loop training with memory"
    - "scalable synchronization and reciprocity calibration for distributed multiuser mimo"
    - "five disruptive technology directions for 5g"

Connected through hyperedge HE-8 (induced by source paper "how much bandpass filtering is required in massive mimo base stations"):
  with members:
    - "massive mimo ten myths and one critical question"
    - "massive mimo with non ideal arbitrary arrays hardware scaling laws and circuit aware design"
    - "what will 5g be"
    - "five disruptive technology directions for 5g"
    - "scaling up mimo opportunities and challenges with very large arrays"
    - "energy and spectral efficiency of very large multiuser mimo systems"
    - "mimo networks the effects of interference"

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)