https://www.nsnam.org/mediawiki/api.php?action=feedcontributions&feedformat=atom&user=TurlettiNsnam - User contributions [en]2026-04-06T07:14:25ZUser contributionsMediaWiki 1.39.8https://www.nsnam.org/mediawiki/index.php?title=Wireless_Phy_in_ns-3&diff=1302Wireless Phy in ns-32006-10-24T17:49:47Z<p>Turletti: small fixes</p>
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<div>The goal of this project is to define a common interface to a set of PHY-level models for wireless transmission mediums spanning a large range of wireless transmission systems:<br />
* 802.11a/b/g<br />
* wimax<br />
* satellite<br />
* ...<br />
<br />
The following sections try to define:<br />
* the characteristics of each wireless transmission system we want to capture<br />
* various models to capture these characteristics<br />
<br />
== 802.11a/b/g ==<br />
<br />
characteristics:<br />
* carrier frequency: b/g: 2.4GHz, a: 5GHz<br />
* signal spread: 22MHz for 802.11b (DSSS)<br />
* 802.11b transmission modes:<br />
** 1Mb/s: DBPSK + barker PN sequence<br />
** 2Mb/s: DQPSK + barker PN sequence<br />
** 5.5Mb/s: CCK + code spread<br />
** 11Mb/s: CCK + code spread<br />
* 802.11a transmission modes:<br />
** 6Mb/s: BPSK + FEC 1/2<br />
** 9Mb/s: BPSK + FEC 3/4<br />
** 12Mb/s: DBPSK + FEC 1/2<br />
** 18Mb/s: DBPSK + FEC 3/4<br />
** 24Mb/s: QAM16 + FEC 1/2<br />
** 36Mb/s: QAM16 + FEC 3/4<br />
** 48Mb/s: QAM64 + FEC 2/3<br />
** 54Mb/s: QAM64 + FEC 3/4<br />
<br />
The MAC layer needs realistic models for the following features:<br />
* interference among multiple stations transmitting at the same time<br />
* resistance of different transmission modes to interference: the 54Mbs mode should resits less than the 6Mbs mode<br />
* signal propagation: attenuation and delay<br />
* so-called "capturing": if a high-energy signal is received during the preamble/header reception of another signal, the high-energy signal crushes the low-energy signal<br />
<br />
So, a typical PHY would be characterized by one of 5 states:<br />
* TX: transmitting some bits<br />
* SYNC: receiving some bits<br />
* IDLE: not doing anything, medium is not busy<br />
* BUSY: not doing anything, medium is busy<br />
* SLEEP: sleeping, not listening to the medium for status<br />
<br />
The condition for BUSY state is precisely defined for 802.11: it is called CCA state detection. There are multiple CCA modes but mode 1 is based on the total energy measured at the antenna. Support for Mode 2 might be needed.<br />
<br />
Notes:<br />
* some people might need multiple SLEEP states: some SLEEP states are deeper than others, take longer to recover from, etc.<br />
* some people want to model antenna directionality. I have zero idea on how to model this.<br />
<br />
Models which fulfill these needs:<br />
* [http://cutebugs.net/files/wns2-yans.pdf yans]<br />
* others ?</div>Turletti