Patent attributes
A radio receiver tunes a radio channel by generating a periodic signal, mixing the periodic signal with received radio signals and passing the mixed signal through a channel filter that has a passband that corresponds to the bandwidth of the tuned channel. The receiver receives allocation information identifying a set of subcarriers in the tuned channel on which to receive an OFDM data signal. It uses this information to receive the OFDM data, modulated on the allocated subcarriers. When the allocated subcarriers span an allocated frequency range that is less than the width of the tuned channel and that is offset from the centre of the tuned channel in an offset direction, the receiver offsets the channel filter from the centre of the tuned channel in the offset direction such that the channel filter passes i) said OFDM data signal, ii) an in-allocation reference signal, and iii) an out-of-channel reference signal. The receiver uses both reference signals to calculate a channel estimate for a subcarrier within the tuned channel.
