MIMO stands for Multiple In Multiple Out, it's the latest antenna technology that wireless internet routers will be using. MIMO uses a multiplexed transmission pattern, so that it sends multiple signals out and is able to receive multiple signals. In simpler terms you can think of it analogous to shooting a billiard ball against the bank to reflect it into your intended target. By bouncing the ball against the bank, you can get to your target if there are other balls in the way.
High frequency RF signals are called Line of Signt (LOS) transmission. Due to the nature of high frequency RF waves (802.11b, g, n all operate at 2.4GHz) do not travel well through obstacles (i.e. walls in you house) so it limits the effective range of Wi-Fi routers. If you've noticed, your router may have a spec range of 300 feet, but you might lose the signal when you're less than 100 feet away from router. That's because the RF energy doesn't travel well through the walls in your house. The nails in the walls tend reflect the energy and scatter it in multiple directions (e.g. think of the cue ball hitting one or more other balls, the cue ball energy is transferred to the other balls and they shoot off in multiple directions). The Wi-Fi range measurement is based on placing a wireless router in an open area and then measuring how far away from the router that the signal can be detected.
MIMO technology uses advanced antenna technology to pick up the low power RF signals that get scattered and reflected around your house. A MIMO router has multiple antennas to transmit and receive multiple RF signals. This technology enables the receiver in the router to composite the multiple, lower power signals, into a usable digital data stream.
For transmission purposes, the MIMO router transmits multiple signals in varying directions to increase the amount of overall RF signal bouncing around in your house. A MIMO enabled wireless adapter can will be able to detect these signals and composite them into a usable digital data stream.
MIMO technology is available in a number of 802.11 pre-N routers. In theory, only a MIMO enabled wireless adapter will be able to take advantaged of the improved signal technology. There is anecdotal evidence that even the current 802.11b/g wireless adapters will experience improved range when connected to a MIMO enabled router.
I just purchased a MIMO router, but haven't hooked it up yet. I'll update this guide after I've set up my new router and let you know if my wireless network's range is improved over my current standard 802.11g router.
Please VOTE on this guide. I spend a lot of time and effort researching and writing my guides. The only compensation I get for my work is your vote; look at it like applauding your favorite group after a concert. I appreciate every vote I get: positive or negative. There all good!
If you have any comments, questions, corrections or suggestions, regarding this guide, feel free to send me an e-mail. I'm always looking to improve my ebay guides.