TrustedReviews posted today a review on the Belkin Wireless Pre-N Router

Whereas conventional access points use single antennae for sending and receiving wireless signals, MIMO uses multiple aerials - hence the triplet of antennae on the Pre-N. It increases performance by using the same wireless channels as conventional products but transmitting more streams of data down them. Hence a single 54Mbit/sec channel can have two streams running at this speed, but combined to produce 108Mbit/sec. MIMO also has to overcome the fact that multiple signals will get mixed up during transmission so it has the ability to recover them correctly at the receiving end.

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