Talk:IEEE 802.11n-2009

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Rubbish[edit]

अरे ये तो बताओ कि ये काम कैसे करती है।

""MIMO technology relies on multipath signals. Multipath signals are the reflected signals arriving at the receiver some time after the line of sight (LOS) signal transmission has been received. In a non-MIMO based 802.11a/b/g network, multipath signals were perceived as interference degrading a receiver's ability to recover the message information in the signal. MIMO uses the multipath signal's diversity to increase a receiver's ability to recover the message information from the signal.""

The diversity that MIMO uses to increase a receiver's ability to recover the message information from the signal, originate from the fact that we have multiple antennas. Even when we are talking about 1 antenna at the receiver/transmitter we still have reflections and YES we take them into consideration (even in the case of SISO) or else we wouldnt be able to decode the symbols due to Intersymbol Interference (ISI). The fact that MIMO offers better BER for a given SNR is because of the multiple antennas(multiple transmition channels) not just multipath. The person who wrote that paragraph is probably a computer scientist that has read about wireless communications in a computer magazine... 147.27.200.12 (talk) 14:28, 21 August 2009 (UTC)

Agreed it was wrong (and unsourced), feel free to write something better with WP:SOURCES. -- KelleyCook (talk) 16:02, 21 August 2009 (UTC)

Okay, so MIMO isn't JUST about multipath, but it does more good than harm in MIMO-OFDM, right? Seems like its worth mentioning.

Multipath remains an advantage for a MIMO-OFDM system since frequency selectivity caused by multipath improves the rank distribution of the channel matrices across frequency tones, thereby increasing capacity.

from http://www.wirelessnetdesignline.com/199601155?pgno=2.

Scottr9 (talk) 16:48, 21 August 2009 (UTC)

Speed[edit]

The speed is listed at a maximum of 248Mbit/s, this is simply incorrect. 270Mbit/s is the actual speed, it is listed earlier in the article as a theoretical speed. I have a wireless N internal card in my HP laptop. I have got it to go 270Mbit/s every single time I have connected to a Wireless-N router. Even more importantly Dual bands aren't even necessary, for this speed. I own 3 WRT310Ns and all work at 270Mbit/s and none are dual bands. The WRT610N also works at 270Mbit/s.

NOTE: Both have to have a simple setting change that makes it go from 20Mhz (130Mbit/s) to 40Mhz (270Mbit/s). This makes it go at full speed.

Need proof?

  • [1] An article somewhat mentioning the 270 speed.
  • [2] The Linksys page for the WRT310N.
  • [3] The Linksys page for the WRT610N.
  • [4] The 'Data Sheet' for the WRT610N that specifically states the 270Mbit/s speed at 40Mhz. Both at 5 & 2.4Ghz. —Preceding unsigned comment added by 76.117.214.244 (talk) 02:37, 13 October 2008 (UTC)


I agree. With 3x3 MIMO (three antennas) you can get 270Mbits/s and 144 with 2x2. You just need to use 20MHz and 40Mhz at the same time at 2.4GHz or 5GHz.

With 3x3 MIMO and operating at 2.4MHz and 5GHz dual-band mode one can get 540Mbit/s. Only legal in the USA because of the 5GHz licence. Zakzor (talk) 16:49, 30 November 2009 (UTC)

"Only legal in the USA..."? Always good to keep in mind the possibility/probability that local 56K dialup ISP competition was driven obsolete because 56K was the legal limit. ...Claimed the twisted-pair system couldn't handle faster. (see anti-competition (anti-American?) regulatory capture).
--108.252.225.238 (talk)Doug Bashford

Comparison chart[edit]

802.11n how can be released in 2009 ? 2007 might be the right number.


I don't think so.

2007 was the date when the first draft came out. And more five of them were released until the 2.0 one. The IEEE standard was only approved in 2009. Zakzor (talk) 16:49, 30 November 2009 (UTC)

axb:c moniker[edit]

Although clearly useful, we need some reliable source for this notation. Otherwise Wikipedia could be seen as promoting it. -- KelleyCook (talk) 20:17, 20 March 2008 (UTC)

I hardly know what you're talking about. What notation? 75.75.72.98 (talk) 20:13, 4 April 2008 (UTC)
Sorry, I had an edit changed the name of the header; its under the Number of antennas section. -- KelleyCook (talk) 20:54, 4 April 2008 (UTC)


Also agree - the discussion of a x b : c under the Number of antennas section is confusing. The number of antennas represented by a and b are both capable of transmitting and receiving.
Kukabura (talk) 17:59, 5 May 2008 (UTC)

Status[edit]

Under April 2008, regarding Draft 4: the external reference link makes no mention of Draft 4 - a corrected link is required.

Kukabura (talk) 17:59, 5 May 2008 (UTC)

I think it is expected that the project status page will be updated shortly with the most timely information. If you like, we can link to http://grouper.ieee.org/groups/802/11/LetterBallots.html which shows the ballot for Draft 4.0 (LB#124) being approved by 88% of respondents. It's not really the nicest page to link to, but we certainly could until the project status page is updated, if that's your preference.
JoelHowe (talk) 11:04, 8 May 2008 (UTC)

Criticism section?[edit]

Every single review of 802.11n equipment (whatever the draft) states that 802.11n falls far short of its nominal specifications. In fact, most reviews have found that 802.11n lags even behind the standard it was supposed to replace, 802.11g, in range as well as speed. So, in the end, what is the point in having this standard? And why has it gone so wrong? 84.254.34.131 (talk) 23:20, 19 May 2008 (UTC)

It's probably best to hold off on a criticism section until the standard is complete. The 802.11n equipment has been out for a while and the latest Draft version just got approved this month, so any equipment that has been tested is out-dated. In reality, those companies that make the Draft-compatible equipment are jumping the gun. There's no guarantee that they will even be compatible with the full standard once it is released. If it doesn't meet its objectives upon full release then we've got something to talk about. But pointing out that there are flaws in draft equipment is like pointing out that there are bugs in beta software. It's to be expected.
JoelHowe (talk) 04:15, 20 May 2008 (UTC)
Moreover, our anonymous reader needs to consult with WP:CRITICISM. -- KelleyCook (talk) 19:03, 20 May 2008 (UTC)

I cannot agree.

There are softwares in use that call themselves "beta" -- but they are major products used by millions, with no sign of the "beta" tag going away. It is appropriate to seriously review such products.

In the case of 802.11n, it is fine to have a theoretical discussion of how it might work someday. But right now, the marketplace is flooded with various "pre-n" products, and most of the people reading this article are interested in these real commercial products. Calling them "draft" does not excuse them from serious consideration. Make separate sections or separate articles if you have to. -69.87.204.105 (talk) 12:36, 2 September 2008 (UTC)

Compatibility with a/b/g[edit]

It's clear from the article that 802.11n devices can coexist with a/b/g devices, but can they communicate with each other? Is it enough to have an "n" AP to allow "a" clients communicating with "b" or "g" clients? With an "n" client, can I connect to "a", "b" or "g" only APs? At what speed? —Preceding unsigned comment added by 195.38.110.188 (talk) 12:35, 25 December 2008 (UTC)


You can communicate with a 801.11b at a rate of 11Mbits/s and a "g" at 54Mbits/s. If the "n" router supports the 5Ghz band you can also communicate with a 802.11a router/receiver at the rate of 54Mbits.

With an "n" client you can connect with any router using their maximum speed except some 802.11a ones. In this case the client must support the 5Ghz mode. Zakzor (talk) 02:14, 4 December 2009 (UTC)

My notebook with 802.11b will get the Blue screen of Death everytime connecting with my n AP. What seem to be the problem? Work fine with g notebook 180.72.27.13 (talk) 09:02, 23 December 2009 (UTC)

Difference between finalization and release dates[edit]

Although maybe technically correct, the article states (at the top) November 2009 as the expected finalization date of 802.11n and (in the comparison table) January 2010 as the release date. According to http://grouper.ieee.org/groups/802/11/Reports/802.11_Timelines.htm (already in the citations), November 2009 is the expected date for "Final 802.11 WG Approval" and "Final or (Conditional) 802 EC Approval" (EC = Executive Committee), while January 2010 is listed for "RevCom & Standards Board Final or Continuous Process Approval".

Wouldn't it be better to have the article mention one date or explain the difference between them? 83.134.79.213 (talk) 09:59, 5 February 2009 (UTC)

Update - CSIRO Patent Dispute[edit]

Ive flagged this as needing updating relating to the CSIRO patent dispute, further new infomation can be found here: http://www.theage.com.au/news/technology/biztech/bonanza-for-csiro-after-landmark-patent-win/2009/04/22/1240079730838.html (23/4/09) —Preceding unsigned comment added by 220.253.4.10 (talk) 16:25, 22 April 2009 (UTC)

WP:BEBOLD -- KelleyCook (talk) 17:22, 22 April 2009 (UTC)
WP:BEBOLD doesn't mean wholesale deletion of pertinant information just because you feel like it. Never slowed the process down? Where have you been? [5] I humbly request someone take a look at this diff and consider if it should be reverted or not. I vote revision, not deletion. For what that's worth. draeath 23:46, 11 September 2009 (UTC) —Preceding unsigned comment added by Draeath (talkcontribs)
Yes, go read the records at https://mentor.ieee.org/802.11/documents?is_group=000n 802.11n was not ever delayed because of the patent dispute ... which was never resolved by the way. It was delayed for many other reasons. Furthermore, this dispute is not 802.11n specific. It applied to all the 802.11 protocols. -- KelleyCook (talk) 09:57, 13 September 2009 (UTC)

Ad-hoc networks ?[edit]

I can't find this info anywhere. Are ad-hoc networks supported in 802.11n ? That is at higher speed than 802.11a/g. Can anyone with 802.11n (draft) equipment try this? That would be great! --Xerces8 (talk) 14:18, 16 July 2009 (UTC)

That would be original research and not citable. It might be better to find a citation...

BlueLeather (talk) —Preceding undated comment added 11:11, 12 September 2009 (UTC).

Just for info, I tried an ad-hoc net with a netbook (Asus EEE 1005HA, Atheros AR9285, Win7 Starter) and a laptop (Toshiba L500-13T, Intel 5100 AGN, Vista). Both unencrypted and with WPA2-PSK. They connected in 54Mbps mode and achieved transfer rates about 20 Mbps (measured with iperf v 1.7). --93.103.185.8 (talk) 18:25, 31 October 2010 (UTC)

Range[edit]

I see there is virtually no mention of the increased range attainable when you use a N router with b/g clients. Could a knowledgeable person write a section on this important aspect of the N class? --Quatermass (talk) 08:39, 6 October 2009 (UTC)

Well find a source and go for it. But my thoughts are the increased range you obtain from using the 11n protocol is almost entirely from the benefits that MIMO has added. But MIMO use requires a client device capable of using MIMO (which if it is strictly G, it can't -- yes I know there many companies put their own proprietary MIMO variations on 11g). On the other hand, due to the years of refining, I imagine that a lot of APs have more efficient designs in general (regardless of which protocol you are connecting with), which means that they have better range for everything connecting to that newer AP, but that has nothing to do with 802.11n itself. -- KelleyCook (talk) 17:46, 8 October 2009 (UTC)

My experience is that the range is not really increased with 802.11n. What 802.11n brings is a bigger throughput at the same distance compared to 802.11g. You won't really reach farther locations but the ones in between will have a better connection. The throughput falls farther with 802.11n. Also the MiMo will make a difference in particular in term of dead spots. But that's the MiMo, not the 802.11n stricto-sensu. —Preceding unsigned comment added by 212.99.48.166 (talk) 11:03, 9 December 2009 (UTC)

Speed limit for WPA-TKIP ?[edit]

I read in an article (Heise c't magazine, issue 7/2010, page 86) that the 802.11n standard mandates a bandwidth limit of max 54 Mbps for stations using WPA-TKIP encryption. Sounds surprising. Can anyone confirm? --Xerces8 (talk) 21:24, 24 April 2010 (UTC)

I think it's due to the fact you are not alloed to use TKIP with 802.11n, so it should then degrade to underlying 802.11a/g AzaToth 22:30, 24 April 2010 (UTC)

802.11N versus 802.11Nlite[edit]

I think we should add this to the article

"... it uses the "nLite" technology also found in TP-Link's TL-WR741ND wireless router. This means that although the router is compatible with 802.11n-enabled adapters and notebooks, it will only deliver a maximum throughput of 150 megabits per second (Mbps). That's half of what 802.11n routers can theoretically achieve, but significantly faster than the 108Mbps limit of enhanced 802.11g routers."

LINK

Also we should see if the range is the same —Preceding unsigned comment added by Vmaldia (talkcontribs) 04:34, 20 September 2010 (UTC)

802.11ac speeds[edit]

The table lists what I think are wrong speeds for the 802.11ac standard. The column under which the speeds are entered is listed as a per-stream speed, and that is what is used for 802.11n, which can hit 2x150=300 with 2 ki7tnbkuytlniyhlinhu byyl ijyglnku streams [Netgear WNDR3800], and 3x150=450 with 3 streams [Netgear WNDR4500]), and presumably hardware capable of 4x150=600 with 4 streams will also eventually pop up.

I believe that for 802.11ac the values are:

433 Mbps is the 80MHz single stream max

867 Mbps is the 160MHz single stream max

with 1/2/4/8 streams, you then get:

433 Mbps, 867 Mbps, 1.73 Gbps, 3.47 Gbps [for 80 MHz]

867 Mbps, 1.73 Gbps, 3.47 Gbps, 6.93 Gbps [for 160 MHz]

However, I haven't read the standard. MaZe Pallas (talk) 06:02, 15 April 2012 (UTC)

Fixed at Template:802.11 network standards. I haven't read the standard either, but found a good whitepaper about it. --cesarb (talk) 23:44, 16 May 2012 (UTC)

Which channels to use?[edit]

On a typical 802.11n router, there are a choice of channels. One might expect that selecting channel 3 would mean "centered on 3, actually spreads over 1-5". But does that mean that if the user chooses channel 1, then half of the benefit of using N mode is wasted (because centered on 1 would also use 2 and 3, but can't use the non-existent 0 and -1?)

Also, if deploying several APs, does that mean that one should use only channels 3 and 9 ? — Preceding unsigned comment added by 78.32.19.201 (talk) 23:58, 22 February 2013 (UTC)


MIMO best antenna orientation?[edit]

With a 3-antenna access point, what's the best way to orient the antennas? Should they be like an inverted tripod, or all parallel? It's not clear whether the 3 antennas should work as a parallel phased array, or as 3 independent axes? 78.32.19.201 (talk) 00:02, 23 February 2013 (UTC)

Out-broadcasting[edit]

Is this still an issue? Is there anything in Out-broadcasting worth merging into this article? ~KvnG 14:08, 27 February 2014 (UTC)