| 摘要 |
A receiver to detect and recover payload data received as Orthogonal Frequency Division Multiplexed (OFDM) symbols, each frame including a preamble including multiple bootstrap symbols, one or more of the bootstrap symbols 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 symbols. A bootstrap processor detects the signalling data from the bootstrap symbols using an estimate of the channel transfer function determined from one or more of the bootstrap symbols, and a demodulator circuit recovers the payload data from the payload symbols using the signalling data. The bootstrap processor comprises a channel shaper, which convolves a time domain copy of the signature sequence with the estimate of the channel impulse response to generate a channel shaped signature sequence 1538, a cross-correlator and a cyclic shift detector 1524. The convolving step may be performed by an equivalent step in the frequency domain of multiplying 1530 the estimated channel transfer function and the signature sequence 1536. A cross-correlator is configured to cross-correlate the useful part of each of the one or more bootstrap symbols with the channel shaped signature sequence, and the cyclic shift detector is configured to estimate the signalling data conveyed by each of the one or more bootstrap symbols by detecting a cyclic shift of the signature sequence present in each of the one or more bootstrap symbols from cross-correlation peaks. |
