In the January 2017 edition of QST, on Page 72, there is an article entitled: TEXTING OFF THE GRID.

Proposed as another communications tool for remote areas without Cell Service.
Like the Mesh Networking we have available to us in Amateur Radio, with several of these, you can create an instant local wireless network (line of sight).

Equipment required: Android or iOS Smartphone

A technology ripe for hacking for Amateur Radio use.
Open Development at:
www.gotenna/pages/sdk