Nuts and Volts - July/August 2018

• Using maximum features, peak ideal data rate is 6. 93

Gbps.

• Typical configuration can produce data rates of over 1

Gbps.

The 802.11ac routers are already becoming the mainstream. While these routers will serve most consumers adequately for years to come, new standards are in the works. Figure 1 shows D-Links’ latest 802.11ac compatible router. The four MIMO antennas boost speed while improving link reliability.

WiGig

WiGig is the trade name given to routers implemented with the 802.11ad standard. WiGig operates in the 60 GHz unlicensed band. Using 2 GHz wide channels and OFDM with 64QAM modulation, it can deliver 7 Gbps of data speed up to about 10 meters max.

Range is really limited by the high millimeter wave signal, but by using agile beamforming and phased array antennas, the range is useable. The 11ad standard and products have actually been around for several years now, but have not gained traction in the marketplace. With limited range and few access points to connect to, the standard has an uncertain future.

One potential use is as wireless connections to virtual reality/augmented reality headsets. Competition from another Wi-Fi standard may commit the 11ad standard to oblivion. We shall see.

The Newest Standard: 11ax

The latest standard is 802.11ax. Chips are now available from vendors like Broadcom and Quantenna that will power the forthcoming new routers. This new standard offers further improvements in speed and coverage. It operates in both the 2. 4 and 5 GHz bands and features the same bandwidths to 160 MHz and 8x8 MIMO. It also adds two key upgrades that will further improve performance.

Post comments on this article and find any associated files and/or downloads at

www.nutsvolts.com/magazine/issue/2018/07.

THE LATEST IN NETWORKING AND WIRELESS TECHNOLOGIES

What Limits Your Data Rate?

We all want downloads to be faster. Unfortunately, there appears to be a diminishing return. Beyond a certain point, humans cannot tell the difference between 10 Mb/s downloads or 50 Mb/s downloads for common uses like email or Internet surfing. It is streaming video that demands the high rates. If the streaming video is not delayed, we usually don’t care what the actual speed is.

Another key factor is the download speed capability of your Internet service provider (ISP) and what speed your account permits. Home cable TV and DSL lines have definite upper limits, and lower than you realize. DSL lines rarely go much beyond about 10 Mb/s. Cable connections can sometimes go up to 50 to 100 Mb/s, but that depends upon what you want to pay for. That said, you should also realize that your actual potential rate is very dependent upon your specific connection and could be lower than the peak promised.

For company APs and public hot spots, the connection is usually a 1 Gb/s Ethernet line. Some office APs may also be on a 10 Gb/s Ethernet switch. A good rate is the usual result but heavy usage can overwhelm any AP.

The point is, you can buy a 1 Gb/s + capable Wi-Fi router but you are never going to see that rate if your ISP can’t deliver it that fast. The weakest link in the data stream chain is the bottleneck. That means, getting a new 802.11ac or 802.11ax router will not in and of itself give you that rate if the ISP cannot match it.

Don’t let that stop you from upgrading as all the newer routers are backward-compatible with the previous 11n standard. And, don’t forget that you need the latest standard like 11ac on both your Wi-Fi device as well as in the router to get the full benefits of the latest standard.

Another good rationale for getting the newer and faster router is link reliability. Since the newer standards and router products use lots of MIMO, the overall link is better, range is extended, and greater whole house coverage is usually better. More users can get faster links and the overall connection is more reliable.