## 3 Experimental Work  
In this part, the expanded multi-carrier OGFDM system is experimentally demonstrated to evaluate the performance in terms of the channel capacity and BER. Therefore, a numerical simulation (MATLAB code) is achieved for the developed design of the OGFDM including five levels of processing (acceleration, filtration, oversampling, allocation, and modulation). Furthermore, to highlight the key advantages of the upgraded OGFDM, the performance is compared with 5G waveform (GFDM). Moreover, the enhanced PHY of the OGFDM is investigated in an electrical back-to-back wireless transmission system. Prior to generating the extended design of the OGFDM, two different design trials are introduced and compared with the initial design case [18]. The main reason behind these tests is to select the optimal PHY that can be favorable to the predicated requirements of future mobile networks. The introduced attempts show that neither an increasing number of subscribers nor supplying higher channel capacity alone can be suitable for the upcoming generations of mobile. Hence, the hybrid solution that combines both the scalability and high transmission rate should be adopted. To clarify more about the OGFDM expansion and how the developed scenario is nominated, the following experimental cases discuss, from a spectrum perspective, the assigned BW for one selected _fc_ in the examined multi-carrier OGFDM system. In case 1 (initial state), as is seen in Figure 3, with 16 frequency subcarriers and \(F_{\text{DAC}}\) corresponds to 4 GHz, the specified sampling frequency (\(F_{\text{DATA}}\)) for one _fc_ is equivalent to 250 MHz. As a result, the achieved bit-rate of each frequency subcarrier equals to 875 Mb/s with aggregated channel capacity equals to 14 Gb/s. In case 2 (subcarriers number increment), the test proposes to increase the number of frequency subcarriers yet leaving the sampling frequency without a change in comparison with case 1. As is clear in Figure 4, with a steady level of sampling frequency (F\({}_{\text{DAC}}\) = 4 GHz) and a dual number of subcarriers (\(K\) = 32), the assigned sampling frequency for one _fc_ is affected badly (F\({}_{\text{DATA}}\) = 125 MHz). Thus, the subcarrier BW is reduced to half of its initial case because of doubling the applied subcarriers without expanding the speed of F\({}_{\text{DAC}}\). Despite the overall channel capacity is still compatible with case1, the bit-rate of each applied subcarrier is descended to 437.5 Mb/s (50% decrement). In case 3 (sampling frequency and number of subcarriers increment), in comparison with case 1, the test introduces a suitable enhancement for both the sampling frequency and the number of frequency subcarriers. As is obvious in Figure 5, an advanced case of transmission is gotten herein by expanding the utilized sampling frequency from 4 to 6 GHz and updating the applied number of subcarriers into 32 (double). Worth noting that, the F\({}_{\text{DAC}}\) of this case can be further enlarged, but since the multi-carrier OGFDM system tends currently to work at the 6 GHz band radio frequency, the employed F\({}_{\text{DAC}}\) is upgraded by only 50% of the initial case. In comparison to the second case, a better sampling frequency (187.5 MHz) is obtained herein which in turn can increase the bit rate of transmission for each utilized subcarrier to 656.25 Mb/s side by side with escalating the overall channel capacity to 21 Gb/s. Since the future applications of mobile tend to increase the number of subscribers yet keeping the bit-rate of each one at a high level, this case that combines both the improved bit-rate and the enlarged number of subcarriers is highly recommended for the expanded design of the multi-carrier OGFDM waveform. Figure 4: Case 2: F\({}_{\text{DAC}}\) = 4 GHz, \(K\) = 32. Figure 3: Case 1 (initial): F\({}_{\text{DAC}}\) = 4 GHz, \(K\) = 16. The following Table 1 can summarize the introduced cases for the OGFDM expansion including the initial case.