Frequency offset estimation algorithm for /spl pi//4-DQPSK TDMA mobile radio

This paper presents a new frequency offset estimation algorithm that uses an indicator of the channel status called the uncertainty factor (UF). The UF is calculated for the burst of interest and used to determine if the frequency offset estimate should be updated. If so, then a number of temporary frequency offset estimates are averaged together to obtain an updated frequency offset estimate. Computer simulations show that the UF is inversely related to carrier-to-interference ratio, and directly related to the frequency selectivity and Doppler frequency of the channel. The new frequency offset estimation algorithm is shown to significantly outperform conventional methods.