Tyler Shield
Tyler Shield is currently a Vice President at Cayman Wireless.
How can commercial wireless do more than 400-600 ft like residential wireless does?
The primary reason for range limitations in traditional wifi is the hidden node issue. Because of this issue a saturated node can’t have many long range clients before the network gets brought down. Commercial wifi ignores this issue using a proprietary protocol that varies by brand that allows the AP to function as a traffic cop. http://en.wikipedia.org/wiki/Hidden_node_problem
Can I have a home network break those rules using commercial equipment?
Yes, however every single radio in the home would need to be commercial grade. Meaning every IPod, laptop… etc. So at this time this is really not possible. You also will have line of sight issue with any transmission over 1000 ft.
What is the different between 900mhz/2.4ghz/5.8ghz?
These are all unlicensed frequencies. As frequency increases so does data, but as it decreases so does object permeability. Example 5.8 can carry the most data but you lose double the gain going through a simple wooden door. 900 MHz data rate is much lower and is only desirable when 2.4 won’t work due to obstruction.
What is channel width and how does it relate to wireless N?
In the 2.4 available spectrum you have 11 channels for use. Wireless G only uses 20 MHz channel at a data rate of 54mbps. If channel 6 is selected a 20 MHz channel take channels 4 to 8. So any new AP would need to be on 1 or 11 to ensure no interference is created. N however with 1 antenna does 65mbps on a 20mhz channel with the option of using a 40mhz channel which would eat up 60+% of the usable spectrum. This brings a data rate of 144mbps on a 40 MHz channel. If your neighbors are using wifi you probably can’t successfully use a 40 MHz channel due to interference. If you are getting random drops in signal this is most likely the cause. Switch back to 20mhz. (These are of course maximum link speeds not actual speeds)
what is MIMO?
This is only available on wireless N technology. This allows multi antennas to transmit and receive allowing for even high rata rates. With a 2×2 antenna chain (Both AP and Client must have this to get the speed but is disparity exists the link will still initialize at the slower speed) on a 20 MHz channel link speed is 150mbps. On a 40 MHz channel it would be 300mbps. (These are of course maximum link speeds not actual speeds)
What is maximum range?
Commercial wifi can go as far as the curvature of the earth will allow. About 23.5 miles near the ground and if you are using an antenna at a height of 1 million ft you could cover the entire hemisphere but no farther regardless of height.
I have a barn on my property about a quarter mile away. Can I get internet access to that location?
As long as line of sight is clear, yes, two commercial radios can easily do this.
Hidden node problem – Wikipedia, the free encyclopedia
en.wikipedia.org
In wireless networking, the hidden node problem or hidden terminal problem occurs when a node is visible from a wireless access point (AP), but not from other nodes communicating with said AP. This leads to difficulties in media access control.