# Indoor Wavelet OFDM VLC-MIMO System: Performance Evaluation
## 3 Simulation Results and Discussion  
### Simulation Parameters  
Here, we display the wavelet-OFDM geometric setup of the VLC-MIMO indoor system executed in a perfect 5 m \(\times\) 5 m \(\times\) 3 m room, clarified in Figure 6[22]. The LED modules and the receiver are arranged and form a 4 \(\times\) 4 VLC-MIMO technique [22]. Their locations in the ceiling are illustrated in Table 1. We suppose a receiver distribution scenario, with locations mentioned in Section 3.2. We consider various values for N = 1, 2, 3, and 4. The key parameter values in simulations are listed in Table 2.  
0.85) at the receiver side. For N = 1, with the increasing of the frequency, the SNR decreases whenever Pre-FDE is not employed for ImR as well as ImADR. The SNR is about 20 dB when Pre-FDE individually or with Pre-SDE is performed as shown in Figure 7a. For N = 2, as the chart illustrates in Figure 7b, the SNR is displayed for the two uneven channels with two different locations of the LED transmitters. When the Pre-FDE is not performed, the SNR is decreased with the increase in frequency. The SNR is higher in the case of ImADR than ImR. After performing the Pre-FDE and Pre-SDE, we found that the SNR of channel 1 is almost the same as channel 2. The Pre-SDE performance after Pre-FDE prevents the system from a large lack in the BER performances. The SNR decreases when a Pre-FDE is performed and Pre-SDE is not performed in two cases, ImR and ImADR, it is almost close to 20 dB of channel 1 and close to the 11 dB of channel 2. Both channels are different. This has a negative effect on the comprehensive BER performance of the system. While the SNR is about 18 dB whenever Pre-FDE is employed before Pre-SDE for the two channels. This near similarity drives the channel to BER improvement. Accordingly, for N = 3 and N = 4, as displayed in Figure 7c,d, respectively, the SNR performance for different channels is very different when Pre-SDE is not performed. This difference negatively affects BER performances. The channels have almost the same SNR output when Pre-SDE is performed after Pre-FDE. In short, the SNR performance can be achieved when the Pre-FDE and Pre-SDE are employed. Figure 7: Signal to Noise Ratio (SNR) performance using Imaging Receiver (ImR) without using Pre- Frequency Domain Equalization (Pre-FDE) and without using Pre-Space Domain Equalization (Pre-SDE), Imaging Angle Diversity Receiver (ImADR) without using Pre-FDE and without using Pre-SDE, ImADR with using only Pre-FDE and ImADR with using Pre-FDE and Pre-SDE, at corner scenario (0, 0, 0.85) of the receiving plane for (**a**) N = 1, (**b**) N = 2, (**c**) N = 3, and (**d**) N = 4. For N = 1, SNR decreases whenever Pre-FDE is not employed for ImR as well as ImADR (pink and green marks). When Pre-FDE individually or with Pre-SDE is performed (red and blue marks), SNR is around 20 dB as shown in Figure 6(a). The Pre-SDE flattened over 50 MHz bandwidth. For N = 2, SNR is displayed for the two uneven channels with two geometric setups of the LED transmitters. SNR decreases in channels 1 and 2 whenever Pre-FDE is not employed for ImR as well as ImADR (pink and green marks). When Pre-FDE individually is performed (blue marks), SNR of channel 1 is greater than that in channel 2. This is because channel 1 is closer to the detector which is located at the corner. When Pre-FDE is performed with Pre-SDE (red marks), SNR is around 17 dB as shown in Figure 6(b). SNR is flattened over the 50 MHz bandwidth due to the Pre-SDE performing. For N = 3, SNR is displayed for the three channels with three geometric setups of the LED transmitters. SNR decreases in channels 1, 2, and 3 whenever Pre-FDE is not employed for ImR as well as ImADR (pink and green marks). When Pre-FDE individually is performed (blue marks), SNR of channel 1 is greater than that in channel 2, and channel 2 is greater than channel 3. That is because channel 1 is the closest one to the detector. When Pre-FDE is performed with Pre-SDE (red marks), the SNR is \(\sim\)19 dB as shown in Figure 6(c).