Design and Implementation of Robust Time/Frequency Offset Tracking Algorithm for MIMO-OFDM Receivers

In this paper, the robust time and frequency offset tracking algorithms and architecture for high throughput wireless local area network (WLAN) systems are presented. The designed architecture has feedback and feed forward compensation loop with well defined loop filter coefficients obtained by various experiments for practical implementation. Considered functional blocks include residual CFO estimator, carrier phase estimator, and timing error estimator. In addition to the algorithm descriptions of these blocks, the implementation method is presented, as they are modeled in the floating/cycle and bit true fixed point C model. These C models have been used as a reference for RTL coding and its verification. The design has been implemented successfully on an FPGA device. The proposed tracking method produces results very close to that of the offset-free system.