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Clear Channel Assessment (CCA) - RF Cafe Forums
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| jkhoo2989
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Post subject: Clear Channel Assessment (CCA)-
Posted: Thu Mar 24, 2005 9:50 pm
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Joined: Tue Mar 22, 2005
5:29 pm
Posts: 5 |
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I found this in IEEE 802.11A Spec -
The start
of a valid OFDM transmission at a receive level
equal to or greater than the minimum 6 Mbit/s sensitivity
(-82 dBm) shall cause CCA to indicate busy with
a probability >90% within 4 µs. If the preamble
portion was missed, the receiver shall hold the
carrier sense (CS) signal busy for any signal 20
dB above the minimum 6 Mbit/s sensitivity (-62 dBm).
How do i intepreated "6 Mbit/s sensitivity (-82
dBm)". Does 6 Mbit/s means the data-rate? and what
is this -82dBm.
How do i intepreted "any
signal 20 dB above the minimum 6 Mbit/s sensitivity
(-62 dBm)"?
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Guest |
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Post subject: Re: Clear Channel Assessment (CCA)-
Posted: Mon Oct 24, 2005 11:29 am
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6 Mbit/s means the phy layer transmission data rate...
and -82 dBm means the recieved power level in dBm...so
the receiver will be busy for a valid OFDM transmission
at a receive level equal to or greater than -82
dBm. If the preamble part of the packet has
not been received due to some reason , say collision,
in that case the sensitivity level is increased
to -62 dBm...so the receiver will be busy for a
valid OFDM transmission at a receive level equal
to or greater than -62 dBm. -- MohaMMad
MuTTakin SiDDique, MSc. Engr Communication Networks
University of Bremen, FB1 Otto-Hahn-Allee NW1
28359 Bremen, Germany EMail:
mms@comnets.uni-bremen.de
Tel : +49 421 218 3339 Fax : +49 421 218 3601
www.comnets.uni-bremen.de/~mms~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
jkhoo2989 wrote:
I found this in IEEE 802.11A Spec -
The start
of a valid OFDM transmission at a receive level
equal to or greater than the minimum 6 Mbit/s
sensitivity (-82 dBm) shall cause CCA to indicate
busy with a probability >90% within 4 µs.
If the preamble portion was missed, the receiver
shall hold the carrier sense (CS) signal busy
for any signal 20 dB above the minimum 6 Mbit/s
sensitivity (-62 dBm).
How do i intepreated
"6 Mbit/s sensitivity (-82 dBm)". Does 6 Mbit/s
means the data-rate? and what is this -82dBm.
How do i intepreted "any signal 20 dB above
the minimum 6 Mbit/s sensitivity (-62 dBm)"?
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Posted 11/12/2012
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