Channel usage

Tony Langdon tlangdon at
Thu Dec 6 14:21:40 EST 2001

> Okay, I am going to take a long walk down a short jetty here, 
> but doesn't
> the use of DSSS within the wireless lan cards mean that this 
> isn't a major
> issue. The other base stations will raise the noise floor of 
> the receiver
> but given the low powers and high rate chipping rates I 
> suspect that the
> effects would be minimal. 

To some extent, this is true.  However, there is a point where the extra
noise floor caused by the interfering station exceeds that of the desired
signal (i.e. the capture ratio may be -x dB, but it's not -infinite).

> I would guess that when the IEEE designed the channels for 
> 802.11 they did
> the calculations to make sure that a 1 channel separation 
> provided enough
> attenuation on the base receiving frequency to remove any interference
> problems.

I dunno if they expected multiple APs to be co located.  IOW, the frequency
separation may be OK for multiple networks sharing the same physical space,
but not if two transmitters are co-located.

On the positive side, it's likely you'll be OK, because you will be running
gain antennas and you won't have APs in each others beam (the power off the
side or back should be less than the normal omni case).

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