Ahhh...the never ending "wifi and WAN integration" saga. Made sense to me in 1999 and still makes sense. Not with hot spots, but with IP PBXs and enterprise wide wifi networks.
Look, the attenuation of a wood-frame construction home is around 12-15 dB. While users don't know what a decibell is, they know that in some places they need to walk outside to make a call. Put another way, 12 dB doubles the range from a base station (cell site) in a land mobile enviornment (10**(12/40))=2.0. So, if the range of the cell site was 4 miles, walking inside a house 2 miles from the base station is the same as traveling an extra 2 miles to the cell "edge" of coverage. In the equation above, the number 40 is the loss of signal in a cellular system in a "decade" (10x....or...going from 1 mile to 10 miles). got it? good. now...
a typical office building is more like 25 dB of attenuation - double that of a house - an that's just to walk inside the front door. The combination of metal frame construction and metalized glass windows really blocks signals. That's your US style 40,000 square foot office building too. If you go to NYC, DC, Hong Kong, etc., those metal/concrete/mirrored glass edifices can be up to 35 dB of attenuation just to walk into the lobby! Interior rooms are much worse (hint: if you are waiting for a call and need to go to one of those interior bathrooms and are worried about the extra 10 dB of attenuation, simply take the elevator up 5+ stories...you get back 2 dB/floor). Using our formula, that is 10**(35/40)=7.5, which means that if your building is 1 mile from the cell tower going inside the building is the same as hopping in a taxi and going 6.5 more miles away (and no doubt passing a few more cell sites).
It's terrible - but everybody knows that. If you looked at the slashdot thread on Nextel PTT vs. Verizon PTT you would notice a common theme: what people really want is their phone to work everywhere...then bring me features. what good are network-based features if you cannot access the network? No good. which (at last) brings me to my point: if you are going to put a wifi network in your office that provides coverage everywhere, why not link that to your cellular service? You would never miss a call. that beats putting wide-band repeaters in the office everywhere. The article below is discussing this topic (again).
IWS: No epiphanies on mobile, Wi-Fi integration
Look, the attenuation of a wood-frame construction home is around 12-15 dB. While users don't know what a decibell is, they know that in some places they need to walk outside to make a call. Put another way, 12 dB doubles the range from a base station (cell site) in a land mobile enviornment (10**(12/40))=2.0. So, if the range of the cell site was 4 miles, walking inside a house 2 miles from the base station is the same as traveling an extra 2 miles to the cell "edge" of coverage. In the equation above, the number 40 is the loss of signal in a cellular system in a "decade" (10x....or...going from 1 mile to 10 miles). got it? good. now...
a typical office building is more like 25 dB of attenuation - double that of a house - an that's just to walk inside the front door. The combination of metal frame construction and metalized glass windows really blocks signals. That's your US style 40,000 square foot office building too. If you go to NYC, DC, Hong Kong, etc., those metal/concrete/mirrored glass edifices can be up to 35 dB of attenuation just to walk into the lobby! Interior rooms are much worse (hint: if you are waiting for a call and need to go to one of those interior bathrooms and are worried about the extra 10 dB of attenuation, simply take the elevator up 5+ stories...you get back 2 dB/floor). Using our formula, that is 10**(35/40)=7.5, which means that if your building is 1 mile from the cell tower going inside the building is the same as hopping in a taxi and going 6.5 more miles away (and no doubt passing a few more cell sites).
It's terrible - but everybody knows that. If you looked at the slashdot thread on Nextel PTT vs. Verizon PTT you would notice a common theme: what people really want is their phone to work everywhere...then bring me features. what good are network-based features if you cannot access the network? No good. which (at last) brings me to my point: if you are going to put a wifi network in your office that provides coverage everywhere, why not link that to your cellular service? You would never miss a call. that beats putting wide-band repeaters in the office everywhere. The article below is discussing this topic (again).
IWS: No epiphanies on mobile, Wi-Fi integration
posted by Spasssmeister at 7:25 PM
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