# LDM-Ex-FDM: A Novel Multi-Service Transmission Scheme for the ATSC 3.0 System
## 4 Simulation Results and Analysis
### LDM-Ex-FDM Performance with Equal Interval Symbol Puncturing (EISP)
Figure 13: BER performance of fixed service in ATSC 3.0 system with and without LDM-Ex-FDM scheme with perfect channel impulse response (CIR) over the AWGN channel, where the parameters of the ATSC 3.0 system were set to \(\Delta=10\) and 12 dB, the \(CL\) constellation was set to QPSK, the \(EL\) constellation was set to NU\(-64\text{QAM}\), and the puncturing rate of the LDM-Ex-FDM scheme were set to \(1/6\) and \(1/12\). As shown in Figures 16 and 17, the BER performance of each service in the LDM-Ex-FDM scheme and the traditional _LDM_ scheme can be compared when the channel impulse response is estimated from the received data. Here, the pilot-assisted least square (LS) channel estimation algorithm is used. A conclusion similar to that shown in Figures 14 and 15 can be drawn from this. Figure 14: BER performance of mobile service in ATSC 3.0 system with and without LDM-Ex-FDM scheme with perfect channel impulse response (CIR) under the multipath channel, where the parameters of the ATSC 3.0 system were set to \(\Delta=10\) and \(12\) dB, the _CL_ constellation was set to QPSK, the _EL_ constellation was set to NU\(-64\)QAM, and the puncturing rate of the LDM-Ex-FDM scheme was set to \(1/12\). Figure 15: BER performance of fixed service in ATSC 3.0 system with and without LDM-Ex-FDM scheme with perfect channel impulse response (CIR) under the multipath channel, where the parameters of the ATSC 3.0 system were set to \(\Delta=10\) and \(12\) dB, the _CL_ constellation was set to QPSK, the _EL_ constellation was set to NU\(-64\)QAM, and the puncturing rate of the LDM-Ex-FDM scheme were set to \(1/6\) and \(1/12\). Figure 16: BER performance of mobile service in ATSC 3.0 system with and without LDM-Ex-Figure 3.0 system were set to \(\Delta=10\) and \(12\) dB, the _CL_ constellation was set to QPSK, the _EL_ constellation was set to NU\(-\)64 QAM, and the puncturing rate of the LDM-Ex-FDM scheme was set to \(1/12\). of QPSK 5/15, as shown in Table 3, in the AWGN channel, by sacrificing 0.27 Mbps of the transmission rate for the _CL_ mobile service, the BER performance gain for the _EL_ service can be up to 0.45 dB. Furthermore, it is possible to increase the BER performance for fixed services by 0.9 dB at maximum if the mobile service can accept a 0.54 Mbps transmission rate loss. In this case, the mobile service can still reach a transmission rate of 2.67 Mbps, which is sufficient for the transmission of 720p mobile service in the typical scenario with _LDM_ in the ATSC 3.0 system [16]. In the more practical multipath channel, the improvement of the received SNR threshold of _EL_ service can be up to 1.8 dB at the sacrifice of 0.27 Mbps of transmission rate loss for _CL_ mobile service. This indicates that the proposed LDM-Ex-FDM transmission scheme will have better performance in a practical system. Therefore, the proposed scheme can achieve a compromise between the demodulation performance of the fixed service and the data rate of the mobile service transmission.