Bug 1888

Summary: COST231 - corrections
Product: ns-3 Reporter: Biljana Bojović <bbojovic>
Component: propagationAssignee: Kirill Andreev <andreev>
Status: RESOLVED FIXED    
Severity: enhancement CC: ns-bugs, tommaso.pecorella
Priority: P5    
Version: ns-3-dev   
Hardware: PC   
OS: Linux   
Attachments: Patch that addresses bug issues.

Description Biljana Bojović 2014-03-21 13:45:49 UTC 
Created attachment 1806 [details]
Patch that addresses bug issues.

The formula that calculates COST231 path loss that is implemented in GetLoss() function of src/propagation/model/cost231-propagation-loss-model.cc is not fully in accordance with corresponding COST231 algorithm (
http://en.wikipedia.org/wiki/COST_Hata_model)

Following points have mismatch:

- units of distance should be in km and not in meters
- units of frequency should be in MHz instead of GHz
- it is used log with some corretcting multiplier instead of using just log10 that is according to COST231 algorithm, this produces some errors.

In attachmente is patch that adresses mentioned issues.
Comment 1 Tommaso Pecorella 2014-03-23 03:37:13 UTC 
+1
Comment 2 Tommaso Pecorella 2014-03-23 03:38:43 UTC 
In the docs, please refer to:
http://www.lx.it.pt/cost231/final_report.htm
Ch. 4, eq. 4.4.3 ì, pg. 135 

instead of using wikipedia.

Thanks
Comment 3 Biljana Bojović 2014-03-23 17:55:21 UTC 
Hi Tommaso,

thanks for reply. I refered to wiki because that was the reference in original ns3 code. 

I took a look into the reference for COST231 that you gave, and my conclusion is that there are still those issues in the ns3 code:

- frequency used in COST231 calculation should be in MHz, not in GHz as it is in current ns3 code
- distance used in COST231 should be in km, not in m
- and on page 134, footnote, of the document that you gave it is said that "1) "log" means "log10"".

Should I add the reference to the code and generate a new patch?

Thanks

Biljana
Comment 4 Tommaso Pecorella 2014-03-23 18:05:47 UTC 
Hi,

the Wiki page reports exactly the same formula as the COST chapter 4.

I like more the original source purely because the wiki page can be changed, the final COST report can't :)

Feel free to link both. Probably it's easier for most people to go to the wiki page.

There's no need to re-generate the patch. I trust you and, after all, it's just a comment.

T.
Comment 5 Tommaso Pecorella 2014-03-26 18:48:44 UTC 
changeset:   10684:156ee4e1f4aa