| 摘要 |
A receiver comprises a radio frequency demodulation circuit configured to detect and to recover a received signal. The received signal has been formed and transmitted by a transmitter to carry the payload data as Orthogonal Frequency Division Multiplexed (OFDM) symbols in one or more of a plurality of time divided frames, each frame including a preamble including a plurality of bootstrap OFDM symbols, one or more of the bootstrap OFDM symbols of the preamble carrying signalling data represented as a relative cyclic shift of a signature sequence which has been combined with the one or more of the bootstrap OFDM symbols. The receiver comprises a detector circuit configured to detect and to convert a useful part of the bootstrap OFDM symbols into the frequency domain, a bootstrap processor configured to detect the signalling data from the bootstrap OFDM symbols in the frequency domain, using an estimate of the channel transfer function determined from one or more of the bootstrap OFDM symbols, and a demodulator circuit configured to recover the payload data from the payload OFDM symbols using the signalling data. The bootstrap processor comprises an equaliser configured to reduce an effect of the channel transfer function in the frequency domain from the bootstrap OFDM symbols carrying the signalling data, a signature sequence remover configured to remove an effect of the signature sequence in the frequency domain from the bootstrap OFDM symbols carrying the signalling data, and a slope estimator configured to detect an average change in phase between adjacent sub-carriers of the bootstrap OFDM symbols after the effects of the channel transfer function and the signature sequence have been removed from the bootstrap OFDM symbols carrying the signalling data. A signalling data detector is configured to identify the signalling data based on the detected average change in phase, which is representative of the cyclic shift applied to the signature sequence. Accordingly, embodiments of the present technique can provide an arrangement for detecting the signalling data from the bootstrap OFDM symbols in the frequency domain. |
