Ask HN: Reosurces to learn about 802.11 in depth?

As the title says I'm looking for resources to get an in-depth understanding of 802.11 in depth, ideally newer versions (at least 802.11n). The standards themselves are more than I'd like to pay, with the latest being over $1000 and majority of other resources I find seem to be either casual explanations of what it is for non-technical people, or resources for designing wireless networks. I did find this book https://www.wiley.com/en-us/IEEE+802+11+Handbook%3A+A+Designer%27s+Companion%2C+2nd+Edition-p-9780738144498, but it's pretty old and there doesn't seem to be a newer edition.