MD simulations of poly(ethylene oxide) (PEO) doped with lithium-bis(trifluoro-methane)sulfonimide (LiTFSI) are analyzed with respect to the cation dynamics, the PEO dynamics as well as their coupling. Different cation transport mechanisms call be identified. These observations call be interpreted in terms of a recently proposed model of cation transport in polymer electrolytes. The model was capable of reproducing the lithium mean square displacement and self-diffusion coefficient. Because of the importance of interchain ion transfers for long-range ion transport, additional focus lies on the analysis of cations coordinated by two PEO chains, which is a common motif in this system.