Bug 1924 – sensing radius and CCA

Bug 1924 - sensing radius and CCA


Summary:	sensing radius and CCA

Status:	NEEDINFO

Product:	ns-3
Classification:	Unclassified
Component:	lr-wpan
Version:	pre-release
Hardware:	PC Linux

Importance:	P5 enhancement
Assigned To:	Sascha Jopen

URL:
Keywords:

Depends on:
Blocks:
	Show dependency tree / graph

Reported:	2014-06-10 21:56 EDT by Tom Henderson
Modified:	2014-06-12 15:48 EDT (History)
CC List:	2 users (show)

See Also:

Attachments
Fix bug with watts not being converted to dB in CCA. Added CCA test. (14.15 KB, patch) 2014-06-12 03:03 EDT, Sascha Jopen	Details \| Diff
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Description Tom Henderson 2014-06-10 21:56:05 EDT

Described here:
https://groups.google.com/forum/#!searchin/ns-3-users/sensing$20radius/ns-3-users/C75VZTPbSkg/h0KiQIdo-asJ

1) m_ccaPeakPower should be initialized to a nonzero value.

2) calculating the CCA energy detection threshold
in dB from values given in watts

Comment 1 Sascha Jopen 2014-06-12 03:03:11 EDT

Created attachment 1846 [details]
Fix bug with watts not being converted to dB in CCA. Added CCA test.

1)
Initializing m_ccaPeakPower to zero is not a problem. It will be overwritten with the actually measured power in any case. The question is, should we add the noise power to the measured signal powers? In the end we compare the ccaPeakPower to the receiver sensitiviy, which also implicitly depends on noise. The same has to be considered for energy detection, not only CCA. For now i will leave it as is.

2)
I fixed the bug with the missing conversion from watts to dB.

Additionally i provided a new test case for CCA with a very simple scenario. For this scenario, CCA seems to work as expected. See the attached patch.

Comment 2 Tom Henderson 2014-06-12 15:48:26 EDT

the db to watts bug was fixed in 10811:31dbab5c8a28

Need more info as to whether/how to address the 1) issue in Sascha's comment.