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: "d mg tradeoff and optimal codes for a class of af and df cooperative communication protocols"
  Abstract: We consider cooperative relay communication in a fading channel environment under the Orthogonal Amplify and Forward (OAF) and Orthogonal and Non-Orthogonal Selection Decode and Forward (OSDF and NSDF) protocols. For all these protocols, we compute the Diversity-Multiplexing Gain Tradeoff (DMT). We construct DMT optimal codes for the protocols which are sphere decodable and, in certain cases, incur minimum possible delay. Our results establish that the DMT of the OAF protocol is identical to the DMT of the Non-Orthogonal Amplify and Forward (NAF) protocol. Two variants of the NSDF protocol are considered: fixed-NSDF and variable-NSDF protocol. In the variable-NSDF protocol, the fraction of time duration for which the source alone transmits is allowed to vary with the rate of communication. Among the class of static amplify-and-forward and decode-and-forward protocols, the variable-NSDF protocol is shown to have the best known DMT for any number of relays apart from the two-relay case. When there are two relays, the variable-NSDF protocol is shown to improve on the DMT of the best previously-known protocol for higher values of the multiplexing gain. Our results also establish that the fixed-NSDF protocol has a better DMT than the NAF protocol for any number of relays. Finally, we present a DMT optimal code construction for the NAF protocol.

Connected through hyperedge HE-1 (induced by source paper "a trellis coded modulation scheme for the fading relay channel"):
  with members:
    - "bounds on the achievable rate for the fading relay channel with finite input constellations"

Connected through hyperedge HE-2 (induced by source paper "fundamental rate reliability complexity limits in outage limited mimo communications"):
  with members:
    - "dmt optimality of lr aided linear decoders for a general class of channels lattice designs and system models"
    - "lr aided mmse lattice decoding is dmt optimal for all approximately universal codes"
    - "space time codes from structured lattices"
    - "on fast decodable space time block codes"
    - "optimal space time codes for the mimo amplify and forward cooperative channel"

Connected through hyperedge HE-3 (induced by source paper "d mg tradeoff of df and af relaying protocols over asynchronous pam cooperative networks"):
  with members:
    - "ofdm based distributed space time coding for asynchronous relay networks"
    - "diversity multiplexing tradeoff of asynchronous cooperative diversity in wireless networks"
    - "approximately universal codes over slow fading channels"
    - "perfect space time codes with minimum and non minimum delay for any number of antennas"

Connected through hyperedge HE-4 (induced by source paper "multi hop cooperative wireless networks diversity multiplexing tradeoff and optimal code design"):
  with members:
    - "diversity and degrees of freedom of cooperative wireless networks"
    - "a deterministic approach to wireless relay networks"
    - "diversity of mimo multihop relay channels"
    - "optimum diversity multiplexing tradeoff in the multiple relays network"
    - "diversity multiplexing tradeoff of asynchronous cooperative diversity in wireless networks"
    - "towards the optimal amplify and forward cooperative diversity scheme"
    - "optimal space time codes for the mimo amplify and forward cooperative channel"
    - "approximately universal codes over slow fading channels"

Connected through hyperedge HE-5 (induced by source paper "diversity multiplexing tradeoffs in mimo relay channels"):
  with members:
    - "on the diversity multiplexing tradeoff in multiple relay network"
    - "diversity of mimo multihop relay channels"
    - "on the achievable diversity multiplexing tradeoffs in half duplex cooperative channels"

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)