Hi Mika,
Hopefully we'll get a number of blended xOFDM / IEEE8xxx.xx
standards, and avoided the fractured mess that we have
here in North America.
A good number of companies (for the most part from the
old countries) are attempting that in the OFDM-Forum,
as you probably know .
For starters, see
ofdm-forum.com
ofdm-forum.com
ofdm-forum.com
ofdm-forum.com
ofdm-forum.com
ofdm-forum.com
ofdm-forum.com
ofdm-forum.com
ofdm-forum.com
As for Adaptive TDD, Wi-Lan (there I go again with the
"W Word" ) also is another one of the many who attempt to
tailor the time slots to the needs of each base station.
And I believe they are also one of a few who use a
Polling scheme, to eliminate the "Hidden Station Problem"
which plagues the Carrier Sensing, Collision Avoidance
scheme.
As I see it, and remembering that this approach dates back
to the pre-transistor, Electro-mechanical Teletype Machine
era .....
Time slots should be tailored to packet length, message priority, and the traffic load of each station.
IMO a Poll & Request scheme is best, dates back to the 1970's IBM Computer days BTW.
Carrier Sensing & Collision Avoidance , with ACK , Non ACK
may work all right .... most of the time, providing ALL
STATIONS CAN HEAR ALL OTHER STATIONS.
But it's kinda slow and a bit dumb IMO.
Since a single antenna DOES NOT allow you to monitor your
own transmissions for data collisions,
you must wait for the ACK or NACK response to see if your transmission was successful.
Better IMO that a number of designated controller stations
do the monitoring and detection of data collisions, set priorities, grant permission to
send , and prescribe TDD slot length for each patient (er station that is).
Perhaps the participants in the collision, could be forced to cease their transmission , immediately, via a service channel of some sort.
Think there's also one newby company (just mentioned a few posts ago) that has totally solved the line of sight problem by mounting a lil ole plastic CPE unit right next to your PC.
Now, it seems that this solves the problem, because
you cannot possibly see the base station through the
walls of your home.
If you mount the little box on a window sill, where
you can see the base station, you are cheating - and
thus violating the non-line of sight criteria.
Well, back to my Lurkin' Mode ..... waiting for the
other shoe to drop .... so to speak.
Cheers, and have a "cool" pint for me..
Old (cantankerous) Mardy. |
