# Indoor Wavelet OFDM VLC-MIMO System: Performance Evaluation
## 3 Simulation Results and Discussion
### Simulation Parameters
\begin{table}
\begin{tabular}{c c c c} \hline \hline  & **Parameters** & **FFT-OFDM [22]** & \begin{tabular}{c} **Present Work** \\ **DWT-OFDM** \\ \end{tabular} \\ \hline \multirow{3}{*}{**Common requirements**} & Number of subcarriers & 64 & 64 \\ \cline{2-4}  & Total number OFDM & 1000 & 1000 \\ \cline{2-4}  & symbols & 1 \(\times\) 64,000 & 1 \(\times\) 64,000 \\ \cline{2-4}  & \begin{tabular}{c} QAM data \\ \end{tabular} & 1 \(\times\) 64,000 & 1 \(\times\) 64,000 \\ \cline{2-4}  & \begin{tabular}{c} Parallel data transmitted \\ \end{tabular} & 1000 \(\times\) 64 & 1000 \(\times\) 64 \\ \cline{2-4}  & \begin{tabular}{c} Parallel to serial data \\ transmitted \\ \end{tabular} & 1 \(\times\) 64,000 & 1 \(\times\) 64,000 \\ \cline{2-4}  & \begin{tabular}{c} Normalized transmitted \\ data \\ \end{tabular} & 1 \(\times\) 64,000 & 1 \(\times\) 64,000 \\ \hline \multirow{3}{*}{**Receiver**} & Normalized received data & 1 \(\times\) 64,000 & 1 \(\times\) 64,000 \\ \cline{2-4}  & \begin{tabular}{c} Serial data received \\ \end{tabular} & 1 \(\times\) 64,000 & 1 \(\times\) 64,000 \\ \cline{2-4}  & \begin{tabular}{c} Serial to parallel data \\ received \\ \end{tabular} & 64 \(\times\) 1000 & 64 \(\times\) 1000 \\ \cline{2-4}  & \
\begin{tabular}{c} De-QAM data \\ \end{tabular} & 1 \(\times\) 64,000 & 1 \(\times\) 64,000 \\ \cline{2-4}  &
\begin{tabular}{c} Output binary data \\ recovery \\ \end{tabular} & 1 \(\times\) 64,000 & 1 \(\times\) 64,000 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Simulation parameters comparison between FFT-OFDM [22] as well as DWT-OFDM, and their corresponding matrix values. is equal to (200 \(\times\) 10\({}^{6}\) samples/sec) \(\times\) (log\({}_{2}\) 62) = 1.2 Gbps, where the QAM constellation order is 64. In the case where the number of channels equals 4, the data rate for all the systems is divided into 4 sections according to 4 LED modules. So, the data rate for every channel is equal to the data rate for the overall system divided by 4. For this reason, the expected data rate capacity is the capacity of all the system itself = 1.2 Gbps. Similarly, in the practical FFT-OFDM system proposed in [22], the data rate for the overall system is equal to (4 \(\times\) 300 \(\times\) 10\({}^{6}\) samples/sec) \(\times\) (1-6.25/100) \(\times\) (1-6/100) \(\times\) (1-7/100) \(\times\) log\({}_{2}\)64 = 983.6 Mbps, where (6.25/100) is the CP percentage, (6/100) is the training sequence percentage (TS), and (7/100) is the forward error correction/channel coding (FEC) percentage as mentioned in [31], where all are added to data transmission. According to our proposed practical DWT-OFDM system, the data rate capacity for all the system is equal to (4 \(\times\) 300 \(\times\) 10\({}^{6}\) samples/sec) \(\times\) (1-0) \(\times\) (1-6/100) \(\times\) (1-7/100) \(\times\) log\({}_{2}\)64 = 1049 Gbps, where 0 is related to no CP percentage added, (6/100) is the TS percentage, and (7/100) is the FEC percentage as mentioned in [31], where all are added to data transmission. The data rate of the DWT-OFDM is higher than that of the traditional-OFDM. The favor of increment is back to removing the CP from our suggested system after transposing DWT-OFDM instead of FFT-OFDM. Table 4 summarizes a comparison between the traditional FFT-OFDM as well as our suggested technique (DWT-OFDM) in terms of coverage contour, bit rate, and BER. In a future work, the proposed system can be implemented in hardware with characteristics mentioned in Table 2, with room dimensions 5 \(\times\) 5 \(\times\) 3 m\({}^{3}\). When the room dimensions are increased, only the numbers of transmitters and receivers will increase. For example, if we choose a standard room with dimensions 9 \(\times\) 9 \(\times\) 3 m\({}^{3}\), the number of LED modules will be 6 modules. So, one needs 6 transmitters and 6 receivers, not 3 as in room dimensions with 5 \(\times\) 5 \(\times\) 3 m\({}^{3}\). These numbers depend on the proper distribution for proper lighting distribution.