Wireless Phy in ns-3: Difference between revisions
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characteristics: | characteristics: | ||
* carrier frequency: b/g: 2.4GHz, a: 5GHz | * carrier frequency: b/g: 2.4GHz, a: 5GHz | ||
* signal spread: | * signal spread: 22MHz for 802.11b (DSSS) | ||
* 802.11b transmission modes: | * 802.11b transmission modes: | ||
** 1Mb/s: DBPSK + barker PN sequence | ** 1Mb/s: DBPSK + barker PN sequence | ||
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** 54Mb/s: QAM64 + FEC 3/4 | ** 54Mb/s: QAM64 + FEC 3/4 | ||
The MAC layer needs | The MAC layer needs realistic models for the following features: | ||
* interference among multiple stations transmitting at the same time | * interference among multiple stations transmitting at the same time | ||
* resistance of different transmission modes to interference: the 54Mbs mode should resits less than the 6Mbs mode | * resistance of different transmission modes to interference: the 54Mbs mode should resits less than the 6Mbs mode | ||
| Line 35: | Line 35: | ||
* 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 | * 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 | ||
So, a typical PHY would be | So, a typical PHY would be characterized by one of 5 states: | ||
* TX: transmitting some bits | * TX: transmitting some bits | ||
* SYNC: receiving some bits | * SYNC: receiving some bits | ||
| Line 42: | Line 42: | ||
* SLEEP: sleeping, not listening to the medium for status | * SLEEP: sleeping, not listening to the medium for status | ||
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 | 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. | ||
Notes: | Notes: | ||
* some people might need multiple SLEEP states: some SLEEP states are deeper than others, take longer to recover from, etc. | * some people might need multiple SLEEP states: some SLEEP states are deeper than others, take longer to recover from, etc. | ||
* some people want to | * some people want to model antenna directionality. I have zero idea on how to model this. | ||
Models which fulfill these needs: | Models which fulfill these needs: | ||
* [http://cutebugs.net/files/wns2-yans.pdf yans] | * [http://cutebugs.net/files/wns2-yans.pdf yans] | ||
* others ? | * others ? | ||
Revision as of 17:49, 24 October 2006
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:
- 802.11a/b/g
- wimax
- satellite
- ...
The following sections try to define:
- the characteristics of each wireless transmission system we want to capture
- various models to capture these characteristics
802.11a/b/g
characteristics:
- carrier frequency: b/g: 2.4GHz, a: 5GHz
- signal spread: 22MHz for 802.11b (DSSS)
- 802.11b transmission modes:
- 1Mb/s: DBPSK + barker PN sequence
- 2Mb/s: DQPSK + barker PN sequence
- 5.5Mb/s: CCK + code spread
- 11Mb/s: CCK + code spread
- 802.11a transmission modes:
- 6Mb/s: BPSK + FEC 1/2
- 9Mb/s: BPSK + FEC 3/4
- 12Mb/s: DBPSK + FEC 1/2
- 18Mb/s: DBPSK + FEC 3/4
- 24Mb/s: QAM16 + FEC 1/2
- 36Mb/s: QAM16 + FEC 3/4
- 48Mb/s: QAM64 + FEC 2/3
- 54Mb/s: QAM64 + FEC 3/4
The MAC layer needs realistic models for the following features:
- interference among multiple stations transmitting at the same time
- resistance of different transmission modes to interference: the 54Mbs mode should resits less than the 6Mbs mode
- signal propagation: attenuation and delay
- 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
So, a typical PHY would be characterized by one of 5 states:
- TX: transmitting some bits
- SYNC: receiving some bits
- IDLE: not doing anything, medium is not busy
- BUSY: not doing anything, medium is busy
- SLEEP: sleeping, not listening to the medium for status
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.
Notes:
- some people might need multiple SLEEP states: some SLEEP states are deeper than others, take longer to recover from, etc.
- some people want to model antenna directionality. I have zero idea on how to model this.
Models which fulfill these needs:
- yans
- others ?