The project stakeholders, their roles and responsibilities, locations, and communication requirements. For ideas, you can refer to projects that are similar to the one you have chosen to work with.
External reporting requirements, if any (news media, government, and so on).
The communication methods (including but not limited to technologies) that would best facilitate the collection and distribution of information without wasting human or other types of resources.
The communication methods currently used by the parent organization, and how those compare to the methods that are best suited to this project.
The information collection and distribution processes within the project. Include the frequencies for collecting and distributing information, controlling the updates, and how handoffs occur.
Descriptions or templates of the formats for different project communications.