Abstract: A receiver apparatus (1) for receiving a signal over a fading channel comprises a frequency domain interpolation unit (16) with a filter unit (10), a power comparison unit (20), and a processing unit (21). The filter unit (10) comprises a first filter element (11), which is a reference filter, and a second filter element (12). The first filter element (11) is arranged as large-band filter. The power comparison unit (20) compares the power of the signal filtered with said second filter element (12) with the power of the signal filtered with said first filter element (11). The processing unit (21) determines an appropriate filter length for a third filter element (13) of the filter unit (10) on the basis of this comparison. Thereby, a trade-off is made between an additional power received due to a long echo and an additional Gaussian noise power.

Abstract: A method of estimating the transmission channel of a received multi-carrier signal in a mobile environment, by identifying pilots present on carriers of the received multi-carrier signal, which pilots comprise continual pilots, performing channel estimation on the received multi-carrier signal using a time-domain interpolator to give a first interpolator output, and performing channel estimation on the received multi-carrier signal using a frequency-domain interpolator to give a second interpolator output. A frequency offset in a continual pilot is detected, and either the first or second interpolator output is selected based on the detected frequency offset. The invention also relates to a system for estimating the transmission channel of a received multi-carrier signal in a mobile environment.

Abstract: A receiver apparatus (1) for receiving a signal over a fading channel comprises a frequency domain interpolation unit (16) with a filter unit (10), a power comparison unit (20), and a processing unit (21). The filter unit (10) comprises a first filter element (11), which is a reference filter, and a second filter element (12). The first filter element (11) is arranged as large-band filter. The power comparison unit (20) compares the power of the signal filtered with said second filter element (12) with the power of the signal filtered with said first filter element (11). The processing unit (21) determines an appropriate filter length for a third filter element (13) of the filter unit (10) on the basis of this comparison. Thereby, a trade-off is made between an additional power received due to a long echo and an additional Gaussian noise power.

Abstract: The invention relates to a method of estimating the transmission channel of a received multi-carrier signal (y) in a mobile environment, which method comprises identifying pilots (P1, P2, . . . , Pk) present on carriers of the received multi-carrier signal (y), which pilots (P1, P2, . . . , Pk) comprise continual pilots (P1, P2, . . . , Pk), performing channel estimation on the received multi-carrier signal (y) using a time-domain interpolator (3, 3?) to give a first interpolator output (30), and performing channel estimation on the received multi-carrier signal (y) using a frequency-domain interpolator (4, 4?) to give a second interpolator output (40). A frequency offset in a continual pilot (P1, P2, . . . , Pk) is detected, and either the first interpolator output (30) or the second interpolator output (40) is selected on the basis of the detected frequency offset.

Abstract: In an OFDM mobile communications system, an algorithm for forming a preliminary estimate of the channel on pilot subcarriers is carried out. Based on this preliminary estimate, a channel property is estimated. This channel property is then used to decide whether to enter a mobile receiver mode or a stationary receiver mode. For example, in the mobile mode channel estimation is performed using only pilot symbols from the current symbol period, while in the static mode channel estimation is performed using pilot symbols from the current symbol period and pilot symbols from other symbol periods.