# A Comprehensive Experimental Emulation For OTFS Waveform RF-Impairments
### Related Work  
Even though the OTFS works well in demanding channel circumstances, RF-impairments must be investigated, validated, and compared to traditional waveform schemes. The PAPR of the OTFS has been analyzed in [20] and its performance has been compared to OFDM waveform. The results show that OTFS has a better PAPR performance compared to OFDM and also show that OTFS has a linear relationship with the number of Doppler bins. The degradation of OTFS BER caused by the power amplifier nonlinearity and I/Q imbalance for the 60 GHz band millimeter-wave testbed is investigated in [21]. To minimize the PAPR in a pilot embedded OTFS, a modified iterative clipping, and filtering (ICF) was proposed in [22]. Furthermore, in [23; 24] the authors minimized PAPR by employing companding approaches; they showed that the \(\mu\) law companding transform provides better performance than the A-law companding transform. The authors of [25] improve the PAPR by presenting an improved SeLective Mapping (SLM) method to provide secure transmission.  
The I/Q imbalance impairments were discussed in [26; 27]; it was demonstrated that the BER performance of the OTFS systems is worsened by I/Q imbalance impairments and has to be compensated. The authors in [28] use a deep neural network (DNN)-based technique to deal with I/Q imbalance. In [29], the authors provide a mathematical study of the I/Q imbalance as well as the direct current (DC) offset. They demonstrated that the image Doppler interference causes a reduction in the performance of the cyclic prefix OTFS (CP-OTFS) system. An innovative approach for compensating the impact of I/Q and DC offset on zero-padding OTFS was developed by the authors of [30]. Furthermore, the authors of [31] effectively compensate the I/Q imbalance for OTFS by using the index modulation (IM) approach. In [32], the authors investigated the effect that phase noise has on the performance of BER when OTFS modulation is present in 28 GHz mm-Wave communications. In addition, they demonstrated that the OTFS is more robust to phase noise compared to OFDM.  
In order to implement the OTFS and study the receiver impairments' effects, software-defined radio (SDR) is used. SDR is a radio communication system where all or most of the physical layer functions have been implemented in software. As discussed in [33], the authors implement an SDR design for the OTFS modem, and investigate the CFO and DC-offset impairments for the real indoor wireless channel. However, in this work, no mobility was considered in the experiment.  
In comparison with the literature, there are only two related experimental papers. In [33], the authors only focus on the CFO and DC-offset. However, Doppler paths are randomly generated in the transmitter from a uniform distribution of random values with the specified maximum number of Doppler paths. Furthermore, the authors did not provide any results that present the effect of the DC-offset on the system's performance. Furthermore, in [21] the authors investigate IQ imbalance and nonlinearity using a 60 GHz Testbed. The authors studied the combined effect of the impairments. Unlike [21], we provide a separate experimental investigation of the IQ imbalance and nonlinearity of the OTFS system and compare it with OFDM for the different number of delay and Doppler bins.