ximum output power. While there is a trade-off between an integrated on-chip PA and an external PA, one can analyze the effect of PA nonlinearity on error vector magnitude (EVM), and thus on the NB-IoT uplink coverage, using an RF and baseband cross-domain simulation technique. In that case, the baseband LTE signal is generated, which supports both single- tone and multi-tone transmission. The baseband signal is filtered by two digital filters and fed into the modulator to generate a spectrum centered at the carrier frequency. The signal is then amplified using an amplifier with certain characteristics. The linearity of the PA can be modeled by setting the 1 dB compression point to an appropriate value. After the signal is amplified by the PA, it is demodulated by the receiver to determine the EVM. For single-tone transmission, the EVM values are very small, less than 0.08% for a 3.75 kHz subcarrier spacing and less than 0.9% for 15 kHz subcarrier spacing [16,17]. Therefore, we can conclude that the nonlinearity of PA has slight effect on the EVM for single-tone trans- mission mode. The studies suggest that PAPR is 4.8, 5.7, and 5.6 dB for a signal with 3, 6, and 12 tones, respectively; thus we can conclude that the nonlinearity of PA has unfavor- able effects on EVM for multi-tone transmissions. From this study one can conclude that, in case of single-tone transmission, some of the PAPR reduction circuit inside the chip can be removed which significantly reduces chip design complexity. Considering the key aspects of NB-IoT applications, devices that only support single-tone transmission combined with an on-chip nonlinear PA are much more advantageous in ultra-low-power and low-cost applications. The NPUSCH provides two subcarrier spacing options: 15 and 3.75 kHz. The additional option of using 3.75 kHz provides deeper coverage to reach challenging locations such as inside buildings, where there is limited signal strength. The data subcarriers are modulated using BPSK and QPSK with a phase rotation of /2 and /4, 