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| What is the differnt between 802.11/b/g/a?? |
| Author |
Hung |
Posted time |
2005-07-27 16:42:58 |
| Contents |
Asthe subject, what is the differnt between 802.11/b/g/a?? |
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| Reply |
Tommy |
Reply Time |
2005-07-28 15:22:20 |
| Contents |
Also this is more information about IEEE 802.11/b/g/a
IEEE 802.11B
Ratitied by the IEE in July 1999, 802.11b extends the original IEE 802.11 direct sequence spread spectrum (DSSS)standard to operate up to 11Mbps in the 2.4Ghz unlicense spectrum using compiementary code keying (CCK) modulation. the fore data rates od 1,2,5.5 and 11Mbps are specified on up to three nonoverlapping channels, and the lowest two rates are also allowed on up to 13 overiapping channels
IEEE802.11G
In July 1999, the 802.11G subcimmittee was tasked to extend the 2.4Ghx unlicensed spectrum to data rates faster than 20Mbps. The resulting 802.11g standard was ratified in June 2003. The 802.11G stabdard provides optional data rates of up to 54 Mbps, and requires backward compatibility with 802.11B devices to protect the subdtantial investments in todays WLAN installations.
The 802.11G standard includes mandatory and optional componets. It specifies OFDM (the same technology used in 802.11a) and CCK as the mandatory modulation schemes with 24 Mbps as the maxi,um ,amdatory date rate, but is also provides for optional higher data rates of 36, 48 and 54 Mbps,
IEEE 802.11A
Ratitied by the IEE at the same time as 802.11B, the IEE 802.11A (802.11A) standard operates in the 5Ghz spectrum. The 802.11a standards was designed for higher bandwidth applications than 802.11B, and includes data rates of 6,9,12,18,24,36,48,54 Mbps using orthogonal frequency division multiplesing (OFDM) modulation on up to 12 discrete channels. |
| Reply |
Big Bear.. |
Reply Time |
2005-07-27 17:15:47 |
| Contents |
This is the information please take look,
802.11b is for 2.4~2.497Ghz,
802.11a is for 5.15~5.35 Ghz or 5.425~5.675Ghz or 5.725~5.875Ghz
802.11g is for 2.4~2.497Ghz,
Also three of them have different data rate,
802.11b is for 1,2,5.5,11 Mbps
802.11a is for 6,9,12,24,36,48,54Mbps,
802.11g will be more rate,
CCK: 1,2,5.5,11 Mbps
OFDM: 6,9,12,18,24,36,48,54 Mbps
At the moment the AP or other system for wireless will be 802.11b/g togehter, and 802.11a is different.
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