802.11ac – the one they called Wi-Fi 5

IEEE Std 802.11ac-2013, Amendment 4 to the 2012 revision, was the one that made **Gigabit Wi-Fi** real. no official "Task Group ac" is named, but whoever drove this forward basically gave the world what we now know as **Wi-Fi 5** – fast, efficient, and finally ready to kill off Ethernet for good (for most people anyway).

802.11ac focused entirely on the **5 GHz band**, where there was more room to breathe than the overcrowded 2.4 GHz space. it brought with it a whole list of serious upgrades, starting with **bigger channel bandwidths** – 80 MHz as standard, and optional 160 MHz for even more speed (if the air was clear enough).

then came **256-QAM modulation**, which packed more bits into each signal – giving better throughput if your signal was strong and clean. add to that **Multi-User MIMO (MU-MIMO)**, which allowed routers to talk to multiple devices at once (instead of one at a time), and support for up to **8 spatial streams**, and you had serious performance gains across the board.

it also introduced the **Very High Throughput (VHT)** PHY and MAC layer – bringing in new capabilities like **VHT Capabilities**, better frame aggregation, more efficient signaling, and smarter resource management for high-density environments.

802.11ac got rolled into the **802.11-2016** standard and still stands strong in the 2020 revision. it’s been the **dominant Wi-Fi standard for years**, powering homes, offices, airports, and just about anything with a fast internet connection. this was the true successor to 802.11n, and it set the stage for the next-gen stuff like Wi-Fi 6 and 6E.

802.11ac was where Wi-Fi got serious about speed. if your router says "AC1900" or "Wi-Fi 5" – this is what’s under the hood. fast, stable, and finally good enough for streaming, gaming, and heavy-duty wireless.