What is ethnography of communication?

Ethnography is the study of people and cultures. It is closely related to anthropology.
thesuperorganic.blogspot.com/2014/08/what-is-difference-between-ethnography.html

More info: www.google.com/#q=define+ethnography+vs+anthropology

So you are asking "What is the study of people and cultures of communication?" If someone thinks those words belong together, it is up to them to explain their thinking.