The Vengeance 2000’s Wireless Tech., Part One: Adaptive Channel Hopping Explained
The Vengeance 2000 7.1 Wireless Gaming Headset receives and transmits digital audio over what is referred to as the 2.4 GHz band. More specifically, the band extends from 2.404 GHz to 2.478 GHz and is one of the so-called ISM (industrial, scientific, and medical) band. It was originally allocated for (as you can imagine) industrial, scientific, and medical purposes other than communication.
These devices are in the 2.4 GHz range to prevent them from interfering with radio communications.
With only so much frequency spectrum available, this band was later made available for use by low-power communications equipment that was capable of dealing with interference from ISM devices. In short, digital transmission protocols with the necessary error-correction capabilities keep functioning, even when the band is very crowded.
Some cordless phones, mobile phones with walkie-talkie features, and Bluetooth devices as well as 802.11b and 802.11g routers use this band. In addition to ubiquitous Bluetooth earpieces, Bluetooth wireless speakers and other gadgets operate at this frequency as well.
At first glance, this might sound scary; when you're using a 2.4GHz device, not only do you need to worry about electromagnetic interference from ISM devices, but there's also the danger of collision with other digital wireless communication devices.
Adaptive Channel Hopping
Since Bluetooth device, wireless networking equipment, and wireless gaming headset vendors want their products to work well, many smart engineers have devoted a lot of time to helping to ensure that all of these unlicensed devices work well with each other. Vengeance 2000 uses a technique called adaptive channel hopping, also known as adaptive frequency hopping, to improve communications.
Like so many other technologies commonly used, adaptive channel hopping was developed for military purposes, such as secure communications over the U.S. Signal Corps Sigsaly system and the remote control of torpedoes. It was independently invented and patented by several people, including one Hedy Kiesler Markey, also known as Hedy Lamarr (her patent is available).
First-generation consumer 2.4 GHz communication devices (think first-generation Bluetooth earpieces) used basic channel hopping. The method was remarkably simple and served as a brute-force solution; they would randomly jump between the approximately 80 available channels in the 2.4 GHz ISM band. No checking was performed to determine if a channel was clear before the device jumped to it. Since the jumps were performed 1,600 times per second, the theory was that if there was a random collision, data would be lost for just one 1600th of a second before the earpiece jumped to the next channel, and you could continue with your conversation without interruption. Collision could occur either with another device using random channel hopping, or with a device (such as a wireless router) using a dedicated channel.
But as more devices began using this band, there was an ever increasing risk of noticeable channel collision, which would happen enough times in a row to result in a period of signal loss that was long enough to notice. But without interference from other ISM band devices, the Vengeance 2000 has unrestricted use of the band with the use of adaptive channel hopping.
Adaptive channel hopping solves the problem by using a number of algorithms to determine if a channel is already in use or otherwise shouldn't be used, and then simply stays away from those channels.
In other words, when you turn on your Vengeance 2000, it has figured out within milliseconds where your wireless router is operating and it makes sure that there is never any frequency interference.
If your neighbor turns on his wireless router halfway through your gaming session, the Vengeance 2000 knows that before it can noticeably interfere with your audio connection.
If it detects the presence of another device using part of the band (in this example, an 802.11g router using channel five), it marks that portion of the band as off limits and constrains its frequency hopping to viable channels.
Channel collision is still possible; for instance, the Vengeance 2000 wireless headset and another channel-hopping device might try to jump on the same channel at the same time. However, this will happen only very rarely and the collision will last for only milliseconds. A lot of engineering hours have been spent to ensure that you simply won't notice when it happens, so you'll enjoy uninterrupted gaming audio.