Performance Analysis of Single Carrier Coherent and Noncoherent Modulation under I/Q Imbalance

Abstract

In-phase/quadrature-phase Imbalance (IQI) is considered a major performance-limiting impairment in direct-conversion transceivers. Its effects become even more pronounced at higher carrier frequencies such as the millimeter-wave frequency bands being considered for 5G systems. In this paper, we quantify the effects of IQI on the performance of different modulation schemes under multipath fading channels. This is realized by developing a general framework for the symbol error rate (SER) analysis of coherent phase shift keying, noncoherent differential phase shift keying and noncoherent frequency shift keying under IQI effects. In this context, the moment generating function of the signal-to-interference-plusnoise-ratio is first derived for both single-carrier and multi-carrier systems suffering from transmitter (TX) IQI only, receiver (RX) IQI only and joint TX/RX IQI. Capitalizing on this, we derive analytic expressions for the SER of the different modulation schemes. These expressions are corroborated by B. Selim, B. Sharif and T. Stouraitis are with the ). 2 comparisons with corresponding results from computer simulations and they provide insights into the dependence of IQI on the system parameters. We demonstrate that the effects of IQI differ considerably depending on the considered system as some cases of single-carrier transmission appear robust to IQI, whereas multi-carrier systems experiencing IQI at the RX require compensation in order to achieve a reliable communication link.

Performance Analysis of Coherent and Noncoherent Modulation Under I/Q Imbalance Effects

“…Assuming differential quadrature phase shift keying (DQPSK) and Rayleigh fading, the bit error rate (BER) under IQI was derived for single-carrier systems in [10] and multi-carrier systems in [11]. Moreover, in [12], assuming single-carrier modulation, the effects of IQI on the SER of different coherent and noncoherent modulations was investigated. Under the assumption of Weibull fading channels and IQI at the receiver only, the average symbol error rate (SER) of M -ary quadrature amplitude modulation (M −QAM) was derived in [13].…”

“…To the best of our knowledge, apart from some sporadic results [12], [40], the effects of IQI on noncoherent modulation have been overlooked by the scientific community. Addi-tionally, the existing results on coherent detection consider case-specific scenarios.…”

“…Thus, they do not provide a holistic treatment of IQI in single and multi-carrier coherent systems. Motivated by this fact, in this article, we extend our work in [12] and investigate the performance of single-carrier and multi-carrier based coherent and noncoherent systems under IQI.…”

On the impact of IQI on cooperative NOMA with direct links in the presence of imperfect CSI

“…In practical implementations, IQI exists in the direct-conversion transceiver due to the inadequate analog components employed in the transceiver. In [22], the authors analyze the impact of IQI on the performance of different modulations under multipath fading channels. The effects of IQI on the OP of both single-carrier and multi-carrier systems cascaded Nakagami-m fading channels were evaluated [23].…”

Performance Analysis of I/Q Imbalance with Hardware Impairments over Fox's H-Fading Channels

“…To this end, there have been several works modeling IQI, studying its impact on system performance, and tackling the problem. For instance, in [5]- [7] and the citations referred therein, the IQI influence on the system performance has been extensively assessed. Moreover, in [8]- [9] and [10]- [12], as well as the references therein, various algorithms for IQI parameters' estimation and calibration have been proposed, respectively.…”