Fundamentals of Wi-Fi 6: Capacity Is the New Metric

[Music] every new wife I release brings all new performance as well as new acronyms like this one 802 dot 11 ax or as we call it now Wi-Fi six it's faster than as you would expect but not in the same way you see rather than bragging rights at the drag strip think great trunk space that are handling in the rain you see Wi-Fi has become a victim of its own success we are surrounded by access points all straining to serve more data hungry devices in fact this has become our high density reality so density refers to the concentration of something like multiple users with wireless devices and as we gather latency gets worse things take more time but look at what happens as density increases on Wi-Fi 6 latency levels off throughput is consistent something is obviously different here we see the 802 11 family dates back to 1997 and every update has made performance improvements mostly from the same three areas the modulation scheme the spatial streams or the channel bonding modulation is the process of shaping an analogue wave to send data and that wave is defined by a frequency where the amplitude and the phase are altered to indicate unique bits of information well Wi-Fi uses quadrature amplitude modulation in 16 qualm means 16 possible areas that can indicate specific symbols higher kwame's higher modulation more bits per symbol like 64 qualm first introduced with 11 in which crude a 256 with 11 AC and now 11a X can modulate as high as 1,024 now that's a lot of data what's not to love don't forget Wireless is an unbounded a shared medium everything affects it every signal must be demodulated and interpreted by the receiving radio so now it may help to look at these squares as targets that get smaller and smaller with each improvement a higher modulation can increase the data rate but these tighter constellations only work in the most pristine low noise situations well let's consider increasing the number of spatial streams MIMO is where a single access point can use multiple radio chains to send and receive more data but very few clients have more than one maybe two antennas so the real bonus comes from mu-mimo where multiple streams connect with multiple users simultaneously but this only works if there's enough spatial diversity physical distance between individual clients which is of course a little more difficult to achieve in high density situations so let's consider our third common improvement channel bonding the five gigahertz band provides 25 non-overlapping channels channels are simply 20 megahertz subdivisions you could double the channel to get to 40 megahertz channels but then you'll only have 12 to choose from 80 megahertz channels exist that I'll drop you to 6 or only 2 if you want to max out at 160 megahertz C channel bonding reduces the number of available channels and since enterprise deployments are using multiple ApS to get the right coverage you need as many chances you can get in fact you may even have to avoid certain channels thanks to your neighbor well when interference is up capacity is down wireless spectrum is a very finite resource so each time you increase the modulation you boost those spatial streams or glue more channels together you're gonna run into these environmental realities as you would expect Wi-Fi 6 has great drag strip numbers in all three areas but for the first time ever there's a fourth airtime efficiency think of airtime is a single Lane 20 megahertz wide there can only be one transmission in one direction at a time will each transmission opportunity is limited to one frame no bigger than 2300 bytes now if you look at your own network you'll see that the average frame is at most 350 bytes which leaves a lot of wasted space wasted space equals wasted airtime in other words it's not efficient well Wi-Fi 6 is addressing this with a big new acronym OFDM a each transmission will now be optimized and combined using smaller reefs source units these are user assigned by the AP to match application requirements which allows multiple clients to transmit in parallel both uplink and downlink so instead of sending one lightly loaded frame for every tiny payload now there could be as many as nine IOT or say real-time video streams each getting a dedicated two megahertz channel with data rates approaching fourteen megabits now that's a huge improvement for each transmission but what about the time wasted just waiting for the the chance to transmit eight or 2.11 devices follow a set of access rules listen before talking if you hear anything wait then try again high-density environments will have more access points carefully tuned to create smaller cells but clients are selfishly shouting at full power and make the channel look busy so others will wait even if they could actually be transmitting Wi-Fi six now offers BSS coloring so that each of these smaller cells or BSS can identify as being on the same team an AP will then offer an incentive for their team members or clients to reduce their power they say you don't have to talk so loud turn your power down I'll give you the preferential channel access net result the entire noise floor goes down each client gets the best quality connection possible well these efficiency gains are also breathing new life into mu-mimo and regardless Wi-Fi six makes it mandatory both down and now upstream this allows acknowledgment frames to respond in a more parallel efficient way than they ever could have before the whole thing can operate more like a system matter recap the efficiency of OFDM a fully optimizing every transmission BSS coloring getting rid of unnecessary wait time all with more capacity than ever before thanks to mu-mimo I just remembered device support is key we need critical Wi-Fi six masts before we will see any of these rewards oh just in case there's any confusion Wi-Fi six is complimentary but not the same thing as 5g it's too big Wireless developments each serving unique parts of the market Wi-Fi six is the most important technology under your control how devices actively transition between both Wi-Fi and the service providers is already getting a lot of focus I wish we had time to cover the other improvements right target wake time better battery management the return of 2.4 gigahertz Wi-Fi 6 is all about the efficiency this better efficiency means better more predictable mileage you

Channel: Cisco

Views: 46,673

Keywords: Cisco, TechWiseTV, Wi-Fi 6, 802.11ax, wireless, IEEE, WFA, WiFi 6, 11ax, High Efficiency, wifi 6 cisco, cisco wifi 6, techwisetv, cisco techwisetv, techwisetv cisco

Id: V5qLv0BtBcM

Length: 7min 22sec (442 seconds)

Published: Fri Apr 12 2019