Index coding with outerplanar side information

We study the Index Coding problem with side information graphs which are outerplanar. For general side information graphs, linearly solving the Index Coding problem implies a linear solution to the general (non-multicast) Network Coding problem - a central open problem in the field of network communication. For outerplanar side information graphs, we show that the Index Coding problem can be solved efficiently, and characterize its solution in terms of the clique cover size of the information graph at hand.