USB Wi-Fi Adapter 101

References
By Jonas DeMuro
published

Wi-Fi 802.11ac

802.11ac introduces other innovations and advancements to Wi-Fi. These include:

  • Dedicated 5GHz bandwidth. While the range of 5GHz is typically less than 2.4GHz, the 5GHz band is significantly less congested and faster - two advantages that make it worth using.
  • While 802.11n channel bonding maxed out at 40MHz, 802.11ac offers this at 80 and even 160MHz. Recall that bonding is the method by which a single 20MHz channel can be combined with other channels to create a multilane highway to enhance data transmission speeds.
  • 802.11n used 64 QAM (quadrature amplitude modulation); 802.11ac increases this to 256 QAM, which is 33% more efficient.
  • 802.11n MIMO (multiple in/multiple out) maxed out at four spatial streams, while 802.11ac doubles this to eight, doubling data throughput.
Jonas DeMuro
Jonas DeMuro
Freelance Reviewer

Jonas P. DeMuro is a freelance reviewer covering wireless networking hardware.

7 Comments Comment from the forums
  • unityole
    hey, in the picture of the disassembled cisco USB wifi module, which model is that?
    Reply
  • Achoo22
    a computer needs to be connected to its network, and in turn the Internet, to be truly useful
    I got this far, then tuned out.
    Reply
  • SuperVeloce
    a computer needs to be connected to its network, and in turn the Internet, to be truly useful
    I got this far, then tuned out.
    okay, I see you don't get what the intended audience in this article is. i'll re-word that for you: "a multimedia family / office work computer needs to be connected to its network..."
    Reply
  • SamSerious
    USB extension cables are often causing problems. I'd never extend a cable by more than one meter and make sure it is a very high quality cable or the voltage will lower dramatically causing the device not to work properly anymore. Or you have to get yourself an active USB expander which is usually quite a bit more expensiv.

    On the other hand, antenna cables are even worse to extend...
    Reply
  • jacobian
    You think you need USB3 to drive a 802.11ac network adapter at full speed? Please. You couldn't have been more confused. Let's say we're talking about a two stream AC device, so theoretically it's capable of 867mbps throughput in 5GHz band. However, much of that number pertains to the "physical layer" information transfer, the chatter that ensures that your data is transferred accurately, under optimal condition (e.g. 6 ft from the router). At TCP/IP level, the throughput will be much lower, even if the distance is short, somewhere in the neighborhood of 100-300mbps, depending on your luck. In other words, a lot less than USB2 can handle.

    You see, the wireless data transfer rates are basically a big marketing scam because half of more of that data transfer rate will disappear due to weakening signal with distance or on the physical layer chatter. Wireless is not like wired Ethernet, where saying 100Mbps really means that you will actually see TCP/IP data transferred nearly at that rate. In the wi-fi world, the marketing can say they sell you a "gigabit ac1750 router (or adapter)", and in real life you may well end up with just 100Mbps or slower data throughput. If you get 200mbps or more, you should be jumping from joy.
    Reply
  • ZeusGamer
    I'm using a dual band PCI Express wi-fi module. For some reason, it's much better than my ethernet connection. Could be because my killer port is only single band rather than dual. I've not lagged one bit with this accessory and I've been using it for at least 8 - 9 months now.
    Reply
  • user_friendly
    Id like to point out that having an external usb wifi can get really hot and malfunction. Its not inside of an air circulated case, so mine tends to get blazingly hot. i have the n600 which i can game on and have no problems. Moslty
    Reply