The net80211 stack and iwm(4) driver now support MIMO in -current. In my own testing, things work just fine. But I have gotten used to breaking other people's wifi without being aware of it. So please test -current and let me know about any regressions.
Because iwm(4) devices have 2 antennas MCS 15 is the maximum Tx rate the hardware will support. Support for 40MHz channels and Tx aggregation are left for future work. I owe several people attribution: This work would have been impossible without the help from Theo Buehler (tb@). He made significant contributions to the implementation of a new rate scaling algorithm which supports MIMO. Thanks to the researchers who released the MiRA paper to the internet. I have studied a dozen papers or so, and eventually decided to implement this one because it was the only paper which documented enough details and which didn't impose impractical requirements. Genua GmbH has funded most of the time I spent working on this project. Without this kind of support I would not have attempted this project.
