OFDM transmitter comprises a frequency de-interleaver and interleaver for the manipulation of pilot symbols.

摘要

An OFDM transmitter preferably for use with a Next Generation Handheld (NGH) standard comprises: a first input from a first data pipe according to a national broadcast channel; a second input from a local service insertion data pipe according to a local service channel; and a modulator 182 which modulates the sub-carrier signals of OFDM symbols with either the data symbols from the first data pipe, using a first lower order modulation scheme, or the data symbols form the first data pipe and the local service insertion data pipe, using a second higher order modulation scheme. A MIMO encoder 189 receives OFDM symbols and forms at least first and second versions of the OFDM symbols which modulate a radio frequency carrier for transmission via first and second antennas respectively. First and second pilot signals are inserted at the pilot sub-carrier of the first and second version of the OFDM symbols respectively. Local pilot symbols are generated at predetermined locations within the first and second OFDM symbols and then de-interleaved the de-interleaver 192 providing the reverse mapping of the interleaver 54.