Performance analysis of otfs under in-phase and quadrature imbalance at transmitter

Armed Tusha*, Seda Dogan-Tusha, Ferkan Yilmaz, Saud Althunibat, Khalid Qaraqe, Hüseyin Arslan

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

15 Citations (Scopus)


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 maximumlikelihood (ML) detection principle. Importantly, our findings prove thatIQimbalanced 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.

Original languageEnglish
Pages (from-to)11761-11771
Number of pages11
JournalIEEE Transactions on Vehicular Technology
Issue number11
Publication statusPublished - 1 Nov 2021
Externally publishedYes

Bibliographical note

Publisher Copyright:
© 2021 Institute of Electrical and Electronics Engineers Inc.. All rights reserved.


  • CSI
  • Doubly dispersive channel
  • Inter-doppler interference
  • IQ imbalance
  • ML
  • OFDM
  • OTFS transmission


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