Retransmission scheduling in 802.15.4e LLDN - a reinforcement learning approach with relayers

We consider the scheduling of retransmissions in the low-latency deterministic network (LLDN) extension to the IEEE 802.15.4 standard. We propose a number of retransmission schemes with varying degree of required changes to the LLDN specification. In particular, we propose a retransmission scheme which uses cooperative relayers and where the best relayer for a source node is learned using reinforcement-learning method. The method allows to adapt relayer selections in face of time-varying channels. Our results show that the relayer-based methods achieve a much better reliability over the other methods, both over static (but unknown) and over time-varying channels.