CTS-toSelf vs. DSSS-OFDM
Last Post: October 20, 2011:
I can only tell you what is reported. No inside info here.
That said, it appears that the major chip manufacturers are breaking off from the IEEE to create something comparable to 802.11n. That is speculation, of course.
What is not speculation is the fact that the IEEE has had a hard time getting 802.11n ratified because of Airgo. Airgo released these "Pre-N" and "RangeMax" type products that are basically 802.11g (2.4 GHz) products with a Multiple Input Multiple Output (MIMO) antenna. They are part of a proposal to make 802.11n have maximum speeds of 108 Mbps, 20 MHz wide bandwidth per channel and reside in the 2.4 GHz band. Some of the major chip manufacturers are in that group as well.
Another proposal wants to use the 5 GHz UNII bands, with 40 MHz of bandwidth per channel and top speeds well above 108 Mbps. More importantly, using the higher frequency would allow for more APs to be co-located (same advantage 802.11a has over 802.11g).
The problem is that the non-Airgo proposal has a majority of votes, but not a "super majority" (75+%) needed to get ratified.
All of that stuff is known. What is thought to also be true by many (including myself) is that Airgo is responsible for the holdup. They are the only chip maker to have products on the market that use MIMO antennas. Therefore, if their proposal is ratified, consumers who bought those products can get a software upgrade to 802.11n. If the alternate proposal gets ratified, Airgo's "Pre-N" equipment becomes obsolete, the consumers who bought it have to buy new equipment if they want to use what enterprises will use and Airgo becomes just another small time chip manufacturer.
If the reports of major chip manufacturers (Intel, Broadcom, Atheros and one other) breaking off from the 802.11n task group are true, that likely means that we are finally going to get a major upgrade in performance across enterprise equipment, whether it is released as "802.11n" or not.
I'm begging you to stop reading Network World.
i have an doubt , how an client or Ap (g)will come to k now that a 802.11b device has come .
suppose we are having all g devices working fine and all of sudden a b device comes in , how will other 802.11g devices will know bout that.
info is in PLCP header or what?
I m not pretty sure bout this ..
You got it.
I have a doubt like ,if DSSS-OFDM is used in physical layer of 802..11g ,how come the 802.11b knows how long 802.11g uses the channel.In preamble it only tells how long it takes to pass tha particular PSDU.
In case of CTS-self it specifies how long 802.11g will occupy the channel.So,even if DSSS-OFDM is implemented should the CTS-self also be used ?.
The simple answer (probably is) - Don't worry about it. You'll never see it, as no one uses it.
If you have a device that does, please identify it.
However, if something did use it, I don't believe RTS/CTS would be needed.