Results » History » Version 6
PASCHOS, Alexandros, 12/15/2015 01:57 AM
| 1 | 1 | PASCHOS, Alexandros | h1. Results |
|---|---|---|---|
| 2 | 1 | PASCHOS, Alexandros | |
| 3 | 1 | PASCHOS, Alexandros | When the communication between the USRPs was established, the transmitted constellation below was obtained. |
| 4 | 1 | PASCHOS, Alexandros | |
| 5 | 3 | PASCHOS, Alexandros | p=. !{width: 30%}https://sourceforge.isae.fr/attachments/download/1513/Tx_Constellation.png(Transmitted Constellation)! |
| 6 | 1 | PASCHOS, Alexandros | _Figure 2.2 Transmitted Constellation_ |
| 7 | 1 | PASCHOS, Alexandros | |
| 8 | 6 | PASCHOS, Alexandros | Using an IQ sampling of 500k, obtaining a symbol rate of 62500 symbols/sec, without any noise, the received constellation is shown below. The $BER$ in this case is, evidently, 0. |
| 9 | 1 | PASCHOS, Alexandros | |
| 10 | 3 | PASCHOS, Alexandros | p=. !{width: 30%}https://sourceforge.isae.fr/attachments/download/1511/Rx_Constellation_no_noise.png(Received Constellation)! |
| 11 | 1 | PASCHOS, Alexandros | _Figure 2.2 Received Constellation without AWGN_ |
| 12 | 1 | PASCHOS, Alexandros | |
| 13 | 1 | PASCHOS, Alexandros | The constellation on figure 11 was obtained when adding AWGN, for a target $E_b/N_0$ (received $E_b/N_0$) of 5.The constellation will vary as the values of $E_b/N_0$ vary, making it either noisier, or making it resemble a noiseless channel. |
| 14 | 1 | PASCHOS, Alexandros | |
| 15 | 3 | PASCHOS, Alexandros | p=. !{width: 30%}https://sourceforge.isae.fr/attachments/download/1512/Rx%20_Constellation_AWGN.png(Noisy Constellation)! |
| 16 | 1 | PASCHOS, Alexandros | _Figure 2.3 Noisy Constellation_ |
| 17 | 1 | PASCHOS, Alexandros | |
| 18 | 4 | PASCHOS, Alexandros | With AWGN, the $BER$ is calculated, then compared to the theoretical one, obtaining a $BER$ vs $E_b/N_0$ graph like the one depicted below in Figure 2.4. It can be seen that the simulated $BER$ follows, as expected, the same behavior as the theoretical $BER$. |
| 19 | 1 | PASCHOS, Alexandros | |
| 20 | 5 | PASCHOS, Alexandros | p=. !{width: 30%}https://sourceforge.isae.fr/attachments/download/1514/BERtheory.jpg(Theroretical an Simulated)! |
| 21 | 1 | PASCHOS, Alexandros | _Figure 2.4 BER vs Eb/No without coding_ |
| 22 | 5 | PASCHOS, Alexandros | |
| 23 | 5 | PASCHOS, Alexandros | The $BER$ is also calculated for a the BCH code or a rate of (roughly) 1/2, and compared to the simulated BER without coding. It can be observed from the graph below, that BCH greatly improves the $BER$. In this case, there is a gain of $3dB$ for a $BER=10^-5$ |