The evaluation of pilot symbol pattern in OFDM system from practical perspective

Pilot subcarriers are very useful in the measurement of channel indicator such as CINR, frequency offset estimation and channel estimation. They are applied widely in many existing standards such as IEEE 802.11, IEEE 802.16 and IEEE 802.22. In this paper, a set of pilot patten is proposed for a network operating in VHF/UHF band based on 802.16 WiMax design pattern. Rationales behind the choice of the pattern will be explained. Evaluation of the performance for the proposed pilot pattern and the WiMax pilot pattern is carried out with different decoding method under AWGN and under different channel models in the VHF/UHF band. The effects of different pilot symbol insertion schemes on the error performance of OFDM-QPSK are evaluated and a mathematical relationship for calculating the gain shift caused by different pilot symbols occupation rate is derived and discussed.