Posted by Eric Huang on December 10th, 2012
You’ve read the first criticisms of the first WiFi-AC routers that have only USB 2.0 and not USB 3.0. USB 2.0 just isn’t fast enough.
You can read our article here at ChipDesign on how Wireless demands Wired USB 3.0 including all the neat data that shows that:
- Draft WiFi-AC is 0.450-0.900 Gbps and faster
- WiFi-N products promise speeds of around 0.300 Gbps (a little less)
- USB 2.0 is only (effectively) 0.320-0.350 Gbps and
- USB 3.0 is 3.850-4.100 Gbps
If you are an early adopter, you already have a WiFi-N setup capable of a theoretical throughput of 0.300 Gbps. If USB 3.0 limits your speeds to ony 0.320-0.350 Gbps, your Draft WiFi AC product will only give you a 10-20% speed boost.
So you really, really, really need USB 3.0 to get the extra 50% to 100% more speed than you got with WiFi-AC.
The real question is:
Why did these first products, these first WiFi-AC chips intentionally NOT include WiFi-AC?
Well, posed this question on a forum I frequent, and here are the responses:
- WiFi-AC doesn’t exist. It isn’t a standard. (And what are you doing in this forum?)
- WiFi-N devices existed at least 2 years before the WiFi-N was finalized (so this must be a draft WiFi-AC product)
- ” There is a very simple reason: Higher phy rate will enable higher cell capacity. For this you do not need very high throughput on a single device but rather you need it to avoid keeping the “air” occupied. Hint: Many CPE 802.11N – the concept is the same”I didn’t understand the last comment because I didn’t understand the last comment.
I suspect 2 other reasons
- As an adapter, there may not have been enough power coming through a USB 2.0 port to power a WiFi-AC radio, and the USB 3.0 controller, and the USB 3.0 PHY.�Again, this is odd because the Power User that buys the Draft WiFi-AC Adapter will be the same Power User that bought the PC with USB 3.0. (And USB 3.0 is mainstream now). So is this poor marketing? I don’t know because I don’t know the guys that specified the WiFi-AC product.
I have no informati0n to back this up except to say that a USB 3.0 PHY will consumer 50% more power than a USB 2.0 PHY in active mode. Since a USB 2.0 port is the most common port, they needed to design for most ports only providing only 2.5 Watts of power. USB 3.0 could provide 4.5 Watts, which seems to me like it would be enough power to power both a WiFi radio and a USB 3.0 which leads me to the next conclusion
- The makers of the Draft WiFi-AC chip did not have either the USB 3.0 controller or USB 3.0 PHY ready at the time they built the Draft WiFi-AC chip when they started designing it in mid-2011.�OR
- They built the USB 3.0 core and PHY and one of those 2 pieces didn’t work, and they fell back on the USB 2.0 functionality which did work.All this leads to is: if those Draft WiFi-AC chipmakers had bought our IP, our USB 3.0 Device and PHY from Synopsys, they would have a product that could sell more units, and for a longer time because it actually delivers the 50-100% speed boost the early adopters needed and are willing toi speend another $300 to upgrade their network for.
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Something slightly Funny
I need subscribers, so I’m going to have to pull out my best stuff now.
Sadly, you get this.
1) When you have friends like I have at work, you never have to worry about my ego getting to big.
2) I reviewed some videos today that will be posted soon. In one of the interviews, I the person I’m interviewing stands pretty far away. So far away, I wonder if I forgot to brush my teeth that morning, or I am just smell bad. When you see the video you will know. Something for you to look forward to.
3) I only ate 1/2 of the top of my chocolate donut Friday. I’m cutting back.
Tomorrow, I will annouce the first (and probably only) USB Christmas Song contest. Rules and Regulations, and maybe even a prize.