Coordinated Rate Splitting Multiple Access for Multi-Cell Downlink Networks

This paper considers a two-cell downlink cellular network with two cell-center users and a cell-edge user. By jointly splitting messages of multiple users into a set of common and private parts, we design a new multi-cell transmission scheme, called the coordinated rate-splitting multiple access (C-RSMA), to effectively manage the inter-cell interference as well as the inter-user interference. Under symmetric channel strength and transmit power, the optimal power split ratios among common and private messages are efficiently obtained with respect to maximizing the weighted sum-rate. Finally, it is shown that the achievable rate region of the proposed C-RSMA is larger than that of existing multi-cell transmission schemes relied on orthogonal multiple access and non-orthogonal multiple access.