Gigabit Wi-Fi 802.11ac In Depth
Presented by Peter Thornycroft
I re-watched Peter's presentation from Aruba's Airheads conference and was impressed all over again. The quality of the slide content was outstanding, the graphics were simple and conveyed a wealth of information without the need for fancy slide transitions. He presented a nice chart of video requirements for different video types (uncompressed/compressed) which can stand on its own as a reference diagram.
I especially liked his slide on 802.11n techniques which cleverly illustrates the advancements that have taken place in the wireless PHY since its inception. Some of the other slides that stood out to me were the sub-carriers for wider channels, the current channels for 5GHz Wi-Fi, MIMO techniques and 802.11ac compared with 802.11n.
Often we hear the term 256 QAM, but understanding how this advancements in PHY modulation achieves higher throughput is often not clarified. Peter explained that 256 QAM is a way of encoding the OFDM symbols to get higher speeds, and by using constellation diagrams to display this visually it is easier to understand how the encoding achieves this.
He also explained explicit feedback beam forming as where the recipient sends the transmitter a packet/information segment that says "this is how you can talk to me to achieve maximum effectiveness."
Peter did an excellent job of presenting this new technology through clear, concise explanations and simple, easy to read slides. If you haven't watched the presentation, or downloaded the slide content, you're really missing out. Do yourself a favor, you need this information.
