Measurement based throughput evaluation of residual frequency offset compensation in WiMAX

WiMAX utilizes a physical-layer based on OFDM that is very sensitive to carrier frequency offset. Even though most of this offset can be compensated using the initial training sequence, there still remains a residual frequency offset due to estimation errors. The methods proposed to correct for this remaining offset are mostly tested by means of pure simulation. In this work, we present outdoor-to-indoor WiMAX measurements in an alpine scenario in which four residual frequency offset compensation schemes are investigated. We evaluate the performance of these schemes in terms of measured throughput rather than only frequency offset estimation error. If a-priori knowledge of the previous receive frame is exploited in a symbol-wise frequency offset estimator, the measurement results show worse performance than simulations predict. Consistent with simulations, the data-aided method effectively compensates the throughput loss due to the residual frequency offset.