Performance Analysis and Compensation of Joint TX/RX I/Q Imbalance in Differential STBC-OFDM

Differential space time block coding (STBC) achieves full spatial diversity and avoids channel estimation overhead. Over highly frequency-selective channels, STBC is integrated with orthogonal frequency division multiplexing (OFDM) to efficiently mitigate intersymbol interference effects. However, low-cost implementation of STBC-OFDM with direct-conversion transceivers is sensitive to In-phase/Quadrature-phase imbalance (IQI). In this paper, the authors quantify the performance impact of IQI at both the transmitter and receiver radio-frequency (RF) front-ends on differential STBC-OFDM systems, which has not been investigated before in the literature. In addition, the authors propose a widely-linear compensation algorithm at the receiver to mitigate the performance degradation caused by the IQI at the transmitter and receiver ends. Moreover, a parameter-based generalized algorithm is proposed to extract the IQI parameters and improve the performance under high mobility. The adaptive compensation algorithms are blind and work in a decision-directed manner without using known pilots or training sequences. Numerical results show that the authors' proposed compensation algorithms can effectively mitigate IQI in differential STBC-OFDM.


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  • Accession Number: 01646275
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Sep 22 2017 4:45PM