SOURCEFORGE » RALF » 2015 Quantitative analysis of RF signals

h3. 2. Estimation of the BER

The BER at the receiving side can be approximated using the signal-to-noise ratio which is provided by the SDR signal analyser. As the type of modulation, the symbol rate, and the type of encoding (given by the standard of the physical layer that is used) are known for each carrier thanks to "Lyngsat Website":http://www.lyngsat.com/Eutelsat-21B.html, a direct relationship between the SNR and the bit error rate can be derived using the following tools:

    +1. Tool 1:+

p=. !Relationship_1.png!

Where:

* E_s = the energy of one received symbol

* N_0 = the power density of the noise

* C = the power of the useful signal

* N = the power of the noise

* B = the bandwidth of the channel

* R_s = the symbol rate

    +2. Tool 2:+

p=. !Relationship_2.png!

Where:

* E_b = the energy of an information bit

* Γ_tot = the spectral efficiency taking into account the spectral efficiency of the modulation and the code rate. A table is given as an example below.

p=. !Total_Spectral_Efficiency.png!

+Table 7: Total Spectral Efficiency according to the modulation and the code rate+

    +3. Tool 3:+ graphs that give the BER regarding Eb/N0, the type of modulation and the encoding  which is used.

p=. !BER_graphs.png!

+Figure 25: Example of graphs+("Reference here":http://www.gaussianwaves.com/2010/04/performance-comparison-of-digital-modulation-techniques-2/)