| 摘要 |
A mobile device in an OFDM system receives an OFDM signal comprising RS tones and data OFDM symbols. The received RS tones are extracted and utilized to perform channel estimation. The resulting raw channel estimates are time filtered by matching channel time variance measured in frequency domain and in time domain, respectively. The measured channel time variance comprises inter-carrier interference measurement and Doppler spread measurement. Mean of differences between neighbor adjacent subcarriers of the extracted RS tones is used for inter-carrier interference measurement. Autocorrelation functions of the raw channel estimates are evaluated for the Doppler spread measurement using, for example, level crossing and/or axis crossing based methods. The raw channel estimates are filtered through averaging and/or recursively filtering using time filter parameters determined based on the inter-carrier interference measurement and the Doppler spread measurement. The time filtered channel estimates are utilized for data demodulation. |
