Amplify-and-Forward Relaying for Hierarchical Over-the-Air Computation
نویسندگان
چکیده
Over-the-air computation (AirComp) has emerged as a promising technique in future intelligent wireless networks, which enables swift functional among distributed devices (WDs) by exploiting the superposition property of channels. This paper studies new hierarchical AirComp network over large area, set intermediate relays are exploited to facilitate massive data aggregation from number WDs. Under this setup, we present two-phase amplify-and-forward (AF) relaying protocol. In first phase, WDs simultaneously send their relays, while second amplify respectively received signals and concurrently forward them fusion center (FC) for aggregation. Our objective is minimize computational mean squared error (MSE) at FC, jointly optimizing transmit coefficients WDs, AF de-noising factor subject individual power constraints. First, consider centralized design with global channel state information (CSI), inter-relay can be beneficially case, develop an alternating-optimization-based algorithm obtain high-quality solution MSE minimization problem. The obtained shows that phase coefficient each WD opposite WD-relay-FC ensure signal alignment WD/relay follows regularized composite-channel-inversion structure strike balance between minimizing signal-magnitude-misalignment-induced noise-induced error. Next, reduce signaling overhead caused design, alternative decentralized partial CSI, FC make own decisions only requiring gain across different relays. need treat harmful interference or noise. Accordingly, optimize associated relay, relay (together factor) iterative manner, implemented efficiently way. Finally, numerical results show fast convergence proposed designs. It also shown both designs achieve significant performance gains benchmark schemes without joint optimization.
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ژورنال
عنوان ژورنال: IEEE Transactions on Wireless Communications
سال: 2022
ISSN: ['1536-1276', '1558-2248']
DOI: https://doi.org/10.1109/twc.2022.3185074