On the Communication Latency of Wireless Decentralized Learning
We consider a wireless network comprising n nodes located within a circular area of radius R, which are participating in a decentralized learning algorithm to optimize a global objective function using their local datasets. To enable gradient exchanges across the network, we assume each node communicates only with a set of neighboring nodes, which are within a distance R n^-β of itself, where β∈(0,1/2). We use tools from network information theory and random geometric graph theory to show that the communication delay for a single round of exchanging gradients on all the links throughout the network scales as O(n^2-3β/βlog n), increasing (at different rates) with both the number of nodes and the gradient exchange threshold distance.
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