Performance Analysis of OTFS Under In-Phase and Quadrature Imbalance at Transmitter

Tusha A., Dogan-Tusha S., Yilmaz F., Althunibat S., Qaraqe K., Arslan H.

IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY, vol.70, no.11, pp.11761-11771, 2021 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 70 Issue: 11
  • Publication Date: 2021
  • Doi Number: 10.1109/tvt.2021.3114000
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, PASCAL, Aerospace Database, Applied Science & Technology Source, Business Source Elite, Business Source Premier, Communication Abstracts, Compendex, Computer & Applied Sciences, Environment Index, INSPEC, Metadex, Civil Engineering Abstracts
  • Page Numbers: pp.11761-11771
  • Keywords: Wireless communication, Time-frequency analysis, OFDM, Interference, Transmitters, Wireless sensor networks, Dispersion, OTFS transmission, IQ imbalance, doubly dispersive channel, OFDM, inter-doppler interference, CSI, ML, AVERAGE POWER RATIO, MODULATION, 5G
  • Yıldız Technical University Affiliated: Yes


The influence of in-phase and quadrature (IQ) imbalance on the performance of orthogonal time frequency space (OTFS) transmission is investigated in this work. OTFS is a recent two-dimensional transmission scheme with promising robustness against the time and frequency selectivity of the time-varying wireless channel, and IQ impairment arises from inevitable imperfections between in-phase and quadrature branches in the transceiver design. In this paper, the mathematical model is presented to illustrate the physical effect of the IQ mismatched transmitter in OTFS, which results in a new type of interference named mirror-Doppler interference (MDI), occurring only along the Doppler axis. Moreover, a closed-form expression for the average bit error rate (BER) of OTFS with IQ imbalanced transmitter is derived taking into account M-ary symbol with a constant envelope and maximum likelihood (ML) detection principle. Importantly, our findings prove that IQ imbalanced transmitter causes a significant reduction in the diversity gain of OTFS transmission, but does not lead to an error floor in the BER performance as in one-dimensional current communication systems. Monte-Carlo simulations are provided to validate the derived mathematical formulas for OTFS transmission with constant envelope M-ary symbols under different system configurations.