WISPr ("Wireless internet service provider roaming") is a type of hotspot setup that is cheap to deploy because all the centralized tracking of usage, as well as command and control of infrastructure, can happen in one centralized system running in a private data center. The rXg can imiplement that centralized system.
One of the fun things I've gotten the chance to work on are WISPr sites. These are sites where a local device, usually an AP in my experience, but potentially a router or other captive portal system, puts network-joiners into a walled garden in which they can only access an External Portal Server. This server then works with the local infrastructure through some kind of controller intermediary to grant access based on purchases or any other factor it chooses.
The MCS Index is a way of comparing and ranking modulation and coding schemes within, and to some degree between, PHY(s).
MCS is an interesting thing to track because it correlates with signal quality. The higher an MCS Index that is used in a transmission, the more susceptible to interference it is going to be.
Some systems do not report MCS directly as an index however. When working with such systems, one can still compute an MCS estimate directly. Here's how.