Confusion regarding Complimentry Error Function "erfc"

[Third Person]

Hi,

If the Prob. of error for a modulation technique is

Pe1 = ½ erfc(Eb/No)

and another modulation technique has,

Pe2 = ½ erfc(2*Eb/No)


can I say that the modulation technique has 3dB power better performance than modulation technique 1?

My reason is that the second can give the same BER at half the Eb/No.

i.e. 20*log10(1/2) ≈ 3 dB

 

[Bhanumurthy]

Hi,
Complementary error function is outdated.All Pe calculations are now done using Q function.As the argument in Q function increases, the Pe decreases.Correspondingly u can relate to Eb/No.

 

[Third Person]

Dear friend, math is never "outdated".

I know that Q function is commonly used, but that doesn't mean erf is outdated.