[Bloat] sigcomm wifi

[Steinar H. Gunderson]

On Sun, Aug 24, 2014 at 02:29:50AM +0300, Jonathan Morton wrote:
> Multi-target MIMO allows an AP to transmit to several clients
> simultaneously, without requiring the client to support MIMO themselves.
> This requires the AP's antennas and radios to be dynamically reconfigured
> for beamforming - giving each client a clear version of its own signal and
> a null for the other signals - which is a tricky procedure.  APs that do
> implement this well are highly valuable in congested situations.

FWIW; I don't think you're right about the nulls. Beamforming has some gain,
and there are some “darker spots”, but they're not what the algorithm is
aiming for (it aims to maximize the signal at the client, not to minimize it
at all other clients), and it's not -inf dB, more like -10 dB.

See in particular http://apenwarr.ca/log/?m=201408#01 and play around with
the applet.

/* Steinar */
-- 
Homepage: http://www.sesse.net/