I'm happy to respond more fully to this:
A) off-list, and
B) when I'm back at my desk
The short answer is, "I don't know" because I don't have your data,
but what assumptions did your modeling make about adjacent channel
rejection figures and CCA thresholds on the clients?
By staying co-channel, you increase the likelyhood of coherent
recovery of the preamble, which greatly aids CCA.
Most 11g/11a chipsets aren't selective enough for three (or even two)
channel operation.
While you could obtain the requisite selectivity, via (say) filtering
or a better receiver front end, you are unlikely to change the client
receivers.
Even weak adjacent channel transmitters will cause enough in-band
signal to de-sense a receiver, which the receiver "sees" as "noise",
directly decreasing SNR, and in-turn impacting both range and recovery
of higher order modulations.
APs, by definion, are strong emitters.
Jim
On Jul 17, 2008, at 12:28 PM, RB <[EMAIL PROTECTED]> wrote:
On Thu, Jul 17, 2008 at 4:01 PM, Jim Thompson <[EMAIL PROTECTED]> wrote:
Assuming you want continiois coverage, same channel is actually
best, unless
you can go cross-band, which impacts roaming.
The number of people who don't understand this, and instead want to
talk
about "3 non-overlapping channels" and other cr*p is amazing.
Jim, I respect the fact that you've been in the industry considerably
longer than me and have likely forgotten more than I know, but what
technical knowledge can you share with us to back a statement like
that? I'm by no means an expert, but the knowledge I'm going on is
pulled from having managed ~500k devices and their networks across ~8k
sites. Are you saying that the extensive RF propagation calculus we
did and compared with hundreds of hours of real-world testing were
completely wrong? I'm open to that, but I'd really be interested in
the why.
RB
