Bug 1504 – Possible wrong calculations in the received Power

Bug 1504 - Possible wrong calculations in the received Power


Summary:	Possible wrong calculations in the received Power

Status:	RESOLVED INVALID

Product:	ns-3
Classification:	Unclassified
Component:	wifi
Version:	ns-3.13
Hardware:	All All

Importance:	P5 major
Assigned To:	Nicola Baldo

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Depends on:
Blocks:
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Reported:	2012-09-15 22:30 UTC by abdo4444
Modified:	2012-09-16 05:20 UTC (History)
CC List:	2 users (show)

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Description abdo4444 2012-09-15 22:30:07 UTC

In the method: YansWifiPhy::StartReceivePacket {....
  rxPowerDbm += m_rxGainDb;
....
}

rxPowerDbm is calculated in terms of (Dbm) while the rxGainDb is by default initialized in terms of (Db). To the best of my knowledge a signal power represented in terms of (Dbm) does not equal the same value represented in terms of (Dbm).

I believe we need to convert them into single unit before the addition, since a value of x in (dbm) = value of x in (db) + 30

Since db is calculated with One Watt as a reference while dbm is calculated with One MilliWatt as a reference value ( in the denominator).

Comment 1 Nicola Baldo 2012-09-16 05:20:15 UTC

It's correct to have gain in units of dB and powers in dBm, because in linear scale powers are in W, but gains are just scalars with no unit.
You're confusing dB with dBW, in fact the formula you gave is for conversion from dBW to dBm.  
Hence I am closing this bug as invalid.