### Related Works  
Orthogonal frequency division multiplexing (OFDM) systems are very sensitive to the IQM because of the close proximity and spectral overlap of the subcarriers. Due to this reason, subcarrier orthogonality is lost, which in turn produces inter-carrier interference (ICI) and performance deterioration [25]. Consequently, employing advanced equalization methods is necessary to lessen the impact of ICI [26; 27]. There is no denying that this dramatically raises the bar for computing complexity. Considering the vast body of literature covering this topic (for examples, see [28; 29; 30; 22] and the citations therein), it is evident that the IQM is a pressing concern. A number of IQM estimate and compensation schemes have been developed, each of which takes into account the IQM at either the recipient or the broadcaster [31; 32]. Combined broadcaster and recipient IQM compensating techniques have been developed [33; 34]. Integrated structures are presented in [35; 36; 37] to assess and adjust for channel and IQM at both the broadcaster and the recipient. To evaluate the IQM, dc offset, carrier frequency offset, and channel coefficients simultaneously in frequency selective channels, a maximum likelihood data-aided approach is presented in [38]. The channel assessment is conducted after the computation of IQM as reported in [39]. Recently, the issue of IQM has been debated for multiple input multiple output (MIMO) OFDM systems, see, e.g., [40; 41]. A capacity analysis of MIMO OFDM systems with IQM and carrier frequency offset is the focus of [42].  
For upstream OFDMA and SC-FDMA systems, the authors of [43] suggest zero forcing and minimal mean square error equalizers, but they assume complete knowledge of the channel impulse response and broadcast IQM. In [43; 44], the researchers created a data-aided technique to predict the channel impulse response and broadcast IQM for OFDMA upstream networks using a two-dimensional least square assessment criteria, and they used a zero forcing equalizer to retrieve the information signal. Nevertheless, a practical system model takes into account both the broadcast and receive IQM, which have been ignored in the earlier research [43; 44]. The authors of [45] investigated the IQM that occurred at the broadcaster and recipient for bit-interleaved coded modulation transmissions in upstream OFDMA systems.  
Symbol error probability over frequency flat channels was calculated analytically in [46; 47] by considering AF dual-hop with IQM at the receiving end. The research that examined the effects of IQI in AF two-way [48] provides lower and upper bounds on the average symbol error probability. Mathematical models for the outage probability and ergodic capacity in m-Nakagami fading channels are discussed in the presence IQI at the relay node [49]. Outage performance in the presence of IQM has been studied for a variety of dual-hop OFDM transmissions [50]. Full-duplex OFDM dual-hop systems have inspired research on least-square channel estimators with IQM [51]. It was proposed in [52] that a pilot-based IQM correcting approach would be useful for AF dual-hop OFDM systems. The efficacy of two-way relaying was studied when the IQM is present at the relay terminal [53]. IQM correction and channel assessment methods have been developed for DF two-path consecutive dual-hop OFDM systems [54; 55]. The authors of [56] used an expectation maximization technique as a low complexity solution to predict the IQM for AF-OFDM systems with the assistance of a minimal number of pilots.