Improve Wireless Networks with MIMO
Theres a new wireless router technology called MIMO - Multiple Input Multiple Output - that promises 8x faster wireless connection for your wireless computer. Your existing wireless connection is slow or sporadic so you've been considering an upgrade. Do the new generation of MIMO routers really work as claimed?
Most wireless connetion problems stem from interference of some kind. You've done everything you could to reduce it - see Peters Top 10 Wireless Network Tips - but nothing has helped.
Wireless Standards
The existing standards to date for wireless networking are A, B and G. The upcoming N standard is expected in late 2006 or early 2007, but nothing is certain except that vendors will introduce the newest technologies before the N standard is officially published.
The IEEE takes years to get a true standard ratified, but vendors will often jump the gun and release products with new technologies to get a head start on their competitors. The same process is being seen now with MIMO. Belkin, for instance, calls their MIMO routers "Pre-N" routers, to signify that they are available before the N standard has been released. Netgear, Linksys, D-Link and Belkin are some vendors that have MIMO routers available today, and more are expected to follow.
The MIMO Difference
It appears that vendors are hawking MIMO as being 8x faster and 3x longer range than Wireless G. But upon closer inspection, the fine print shows that this is only the case under certain circumstances.
MIMO uses multiple antennas and overlays the signals so they don't get mixed up. It then combines these two signals and can get an effective speed of 108 Mbps. But 108 certainly isn't 8x faster than Wireless G's 54 Mbps! What's going on here?
MIMO uses a second technology to improve things. Before, signals would bounce around and Wireless G would only be able to maintain one connection between the router and a wireless device. But the MIMO routers can actually use multiple distinct radio streams over the same signal at the same time. (This is known as "spatial multiplexing".)
What this all means is that the farther away a router is from the wireless computer, the more paths the reflected signals will take, and for longer distances this means an increased speed. So for a MIMO wireless router and PC in the same room, the speed will be 2x a normal wireless G. If you placed the computer 3 rooms away, it would be 4x faster than a G at that range - not 4x faster than G! And for example out in the back yard, it would be 8x faster than a Wireless G router at that range. So in the last example, you might get 5 Mbps with Wireless G, but with MIMO you'd get 40 Mbps.
Sharing the Sandbox
One question that requires an answer is, "does MIMO work with my non-MIMO computer or notebook?" Fortunately the answer is yes. Using a MIMO router with a standard Wireless G or even a Wireless B network card will show improvements in range. This is because MIMO conforms to the WiFi standard, which simply means that signals in the same frequency range will work together, no matter what vendor's equipment is. So a Belkin router using MIMO will work with your regular old Wireless B or G notebook.
Recommendation
As a bridging technology to the upcoming Wireless N standard, I highly recommend routers with MIMO technology now. They work with your existing equipment and will help to maintain a higher speed connection at a longer range.
Most wireless connetion problems stem from interference of some kind. You've done everything you could to reduce it - see Peters Top 10 Wireless Network Tips - but nothing has helped.
Wireless Standards
The existing standards to date for wireless networking are A, B and G. The upcoming N standard is expected in late 2006 or early 2007, but nothing is certain except that vendors will introduce the newest technologies before the N standard is officially published.
| Standard Name | Common Name | Speed (Mbps) | Range | Available |
|---|---|---|---|---|
| 802.11a | Wireless A | 54 | short | now |
| 802.11b | Wireless B | 11 | medium | now |
| 802.11g | Wireless G | 54 | medium | now |
| not a standard | Super-G | 100 - 108 | medium | now |
| not a standard | Wireless G + MIMO | 100 - 108 | long | now |
| 802.11n | Wireless N | 108 | long | 2006/2007 |
The IEEE takes years to get a true standard ratified, but vendors will often jump the gun and release products with new technologies to get a head start on their competitors. The same process is being seen now with MIMO. Belkin, for instance, calls their MIMO routers "Pre-N" routers, to signify that they are available before the N standard has been released. Netgear, Linksys, D-Link and Belkin are some vendors that have MIMO routers available today, and more are expected to follow.
The MIMO Difference
It appears that vendors are hawking MIMO as being 8x faster and 3x longer range than Wireless G. But upon closer inspection, the fine print shows that this is only the case under certain circumstances.
MIMO uses multiple antennas and overlays the signals so they don't get mixed up. It then combines these two signals and can get an effective speed of 108 Mbps. But 108 certainly isn't 8x faster than Wireless G's 54 Mbps! What's going on here?
MIMO uses a second technology to improve things. Before, signals would bounce around and Wireless G would only be able to maintain one connection between the router and a wireless device. But the MIMO routers can actually use multiple distinct radio streams over the same signal at the same time. (This is known as "spatial multiplexing".)
What this all means is that the farther away a router is from the wireless computer, the more paths the reflected signals will take, and for longer distances this means an increased speed. So for a MIMO wireless router and PC in the same room, the speed will be 2x a normal wireless G. If you placed the computer 3 rooms away, it would be 4x faster than a G at that range - not 4x faster than G! And for example out in the back yard, it would be 8x faster than a Wireless G router at that range. So in the last example, you might get 5 Mbps with Wireless G, but with MIMO you'd get 40 Mbps.
Sharing the Sandbox
One question that requires an answer is, "does MIMO work with my non-MIMO computer or notebook?" Fortunately the answer is yes. Using a MIMO router with a standard Wireless G or even a Wireless B network card will show improvements in range. This is because MIMO conforms to the WiFi standard, which simply means that signals in the same frequency range will work together, no matter what vendor's equipment is. So a Belkin router using MIMO will work with your regular old Wireless B or G notebook.
Recommendation
As a bridging technology to the upcoming Wireless N standard, I highly recommend routers with MIMO technology now. They work with your existing equipment and will help to maintain a higher speed connection at a longer range.
posted by Peter at
8:24 AM
